Recent Submissions

  • Desempenho de três linhagens de Tilápia do Nilo (Oreochromis niloticus) em diferentes fases, densidades e níveis de proteína.

    Fulber, V. M. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2007)
    The present work objective to evaluate the productive performance of three Nile Tilapia (O. niloticus) lines during the initial and growing phase in different stocking densities also during the final phase with different crude protein levels (25 and 30%). The evaluated lines were: Bouaké, Chitralada and GIFT (Geneticaly Improved Farmed Tilapia). The experiment was carried out in three phases from February to November of 2006. in the first two phases it was used a kind of greenhouse installation, with a total of 500L water box were it was tested three Nile Tilapia lines and three stocking densities (15, 20 and 25 fish per box). In the initial phase, with a lasting of 28 days from February to March of 2006 and (06, 10 and 14 fish per box) during the growing phase with 53 days of lasting from March to April of 2006. Each phase characterized by nine treatments with three replications. The final phase had 204 days and was from April to November of 2006. For so, the fish were individually marked with an electronic Passive Integrated Transponder (PIT) tags implanted in the abdomen, guarantying the secure and permanent identification of fish using a code formed by letters and numbers that allowed the lecture by using an electronic lecture scanner. The final phase last 204 days and was carried out from April to November of 2006. There were used three fish lines totalizing 230 fish that were proportionally divided and allocated in two land tanks of 140m2 each one. Each tank received commercial rations with different crude protein (CP) levels being 25% of CP for one tank and other one with 30% of CP. The water quality parameters kept adequate for the different densities during the first two phases not affecting lines performance. In the initial phase comparing the densities inside the same line, Chitralada and GIFT did not show difference. However, Bouaké line showed sensibility to the stocking density increase with total final length average, final weight and gain weight significantly lower to the higher evaluated density while the surviving rate kept normal levels to this specie phase. The growing phase results to the average final performance showed differences (P< 0.05) among evaluated densities inside the same lines, being the lower density the most efficient. But comparing the same density among the different lines it was not observed significant differences. The different densities showed a straight relation between the increased density and performance reduction. In the final phase the average temperature during the winter contributed to the feed ingestion restriction by fish during the coldest days what could have influenced the lines performance. However, when evaluating the water quality parameters it was observed that the averages for these factors kept satisfactory to the adequate specie growing. The average performance of fish fed with ratio containing 25% of CP were higher in 46.0%, 35.0% and 51.0% for Bouaké, Chitralada and GIFT, respectively, when compared to the fish of the same line that received ration with 30% of CP, showing an inverse relation between CP levels increase and productivity, suggesting a lower CP levels necessity to Nile tilapias diet during the final phase, decreasing the ambient impact with lower nitrogen amounts being lost and also decreasing the cost production since protein is the most expensive ingredient of rations and does not necessary affect the biological value. Comparing the three tilapia lines performance, the GIFT showed to be the most efficient for all evaluates parameters independent of the crude protein level supplied, followed by Chitralada and Bouaké. The most efficient average of GIFT in relation to the others lines reported its potential genetic improvement in relation to the no improved lines.
  • Crioconservação de embriões de tambaqui (Colossoma macropomum).

    Fornari, D. C. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2012)
    Cryopreservation of genetic material of fish has become a tool essential for preservation of biological materials and production. However, stocking of fish embryos in liquid nitrogen (-196°C) and maintain indefinitely is not yet possible. Recently, developments in research on cryopreservation allowed storing embryos at -8°C for 24 hours. This indicates the possibilityof fish embryo cryopreserving, moreover, the biotechnical cooling for a short time already has practical applications. The present study aimed to evaluate the efficiency of different cryoprotectants to the processes of cryopreservation (freezing, vitrification and cooling) of tambaqui embryos (Colossoma macropomum). Despite not having succeeded in tambaqui embryos cryopreservation important points has been clarified as related to damage to the embryos. Injuries and morphological changes in embryos were identified at all stages of the freezing process, being higher with stabilization at -35°C after being submerged in liquid nitrogen and thawed. At the moment of the seeding besides a lower incidence of injuries, higher percentage of embryos with chorion were observed. The freezing curve protocolstested have not prevented the formation of ice crystals, thus turning unfeasible the embryonic embryos C. macropomum freezing. In the experiment of vitrification the methanol 20% with two-minutes of pre-immersion in exposure to liquid nitrogen, preserved the chorion and some cellular structures. Although it avoided further damage was not sufficient to prevent mortality of embryos, these results open perspectives for continued studies on cryopreservation of fish embryos. Ethylene glycol, glycerol and DMSO were toxic at higher concentrations (20 and30%) not being interesting for the vitrification of embryos C. macropomum. In tests of cooling to at -8°C treatments with ethylene glycol, glycerol and DMSO associated withsucrose did not result in satisfactory answers. To store embryos of C. macropomum at -8°Cfor a period of six hours is suggested cryoprotectant solutions with 17% sucrose combinedwith 10% methanol.
  • Desenvolvimento de misturas liofilizadas para croquete de tilápia do Nilo.

    Fuchs, R. H. B. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2013)
    The Nile tilapia (Oreochromis niloticus) is a fish whose production is growing worldwide. It has mild flavor, low fat and high acceptability, being consumed mainly in the form of fillets. However, this cut represents only 30-35% of the live weight of the fish. The meat which is adhered to fish carcass after filleting process may be removed and used in the development of new food products. This meat is called mechanically separated meat (MSM) or tilapia mince. The objective of this study was to use the MSM of Nile tilapia in developing freeze-dried mixtures of fish croquette, enrich it with flaxseed flour to increase your omega-3 content and evaluate the chemical, microbiological and sensory stability for 240 days. Cost, fiber content and sensory analysis of flavor, texture and overall acceptance of seven formulations of tilapia croquette were evaluated, varying levels of wheat, oats and rye used in its production. A genetic algorithm (GA) with desirability functions was combined with a multiobjective optimization of the response surface models. The optimized mixture, called basic formulation was freeze-dried until a constant value for water activity (aw) was obtained. Through a preference ranking test (p <0.05), it was determined the higher content of flaxseed flour can be added to the basic formulation, with no changes to the basic formulations and the enriched one. The two formulations, raw and deep fried in soybean oil had their proximal composition and fatty acid composition determined. Indices of nutritional quality of lipids from the basic and enriched formulations (raw and deep fried) were also evaluated. The parameters evaluated were index of atherogenicity (AI), index of thrombogenicity (IT) and ratio HH (hypocholesterolemic fatty acids/ hypercholesterolemic fatty acids). The freeze-dried samples of mixtures of tilapia croquete were vacuum packed in transparent plastic bags with a thickness of 180? and stored in dark plastic boxes at room temperature (24oC ± 3oC). The stability of both formulations were evaluated through analysis of TBARS and aw (on days 0, 30, 60, 90, 120, 150, 180, 210 and 240), total and fecal coliforms, Staphylococcus coagulase positive, molds and yeasts, Bacillus cereus and Salmonella sp (on days 0, 120 and 240) and sensory acceptance of the attributes appearance, texture, odor, flavor and overall acceptance (on days 0, 210 and 240), using 9-point hedonic scale. The combination of flours was chosen to minimize the cost and maximize the overall acceptance and fiber content. The overall acceptance showed a statistically significant correlation (p?0.05) with flavor (r=0.67) and texture (r=0.61). The GA-based approach indicated that the highest overall acceptability is obtained when using wheat and rye flours in equal parts. This formulation had an overall acceptance of 7.52, fiber content of 11.50 g kg-1 and cost of $ 2.21/ kg. After 24 hours of freeze-drying the water activity of the mixture was 0.11. The ranking preference test indicated that the limit of addition of flaxseed flour is 12.5 g 100 g-1. In addition to the enhanced content of omega-3, the enriched formulation showed a lower loss of this substance during frying and better indices of nutritional quality of lipid than the basic product. The water activity of mixtures increased significantly (p <0.05) ranging between 0.1666 and 0.5392 (control mixture) and between 0.0554 and 0.5415 (enriched misture). TBARS values were increased significantly (p<0.05), from 0.08 to 0.38 mg MDA kg-1 (control mixture) and 0.11 to 0.40 mg MDA kg-1 (enriched mixture). The attributes appearance, texture and overall acceptance of the control mixture remained constant and flavor was improved during storage. During the evaluation period, the enriched mixture did not change the acceptance of its sensory attributes (p<0.05). After 120 days of storage, the control mixture showed significantly higher overall acceptance than the averages of the enriched mixture. At the end of the evaluation, the overall acceptance was approximately 8 for control mixture and 6 for the enriched mixture. Microbiological parameters did not exceed the limits allowed for consumption. The use of genetic algorithm was a suitable tool in the optimization process of the basic formulation of tilapia croquette and freeze-drying contributed to the development of a product with high added value, high quality and stability. The enrichment of the basic formulation with flaxseed flour increased its nutritional value, with a high content of omega-3 fatty acids and improved IA, IT and HH ratio, even when this product is subjected to deep fat frying. Control and enriched freeze-dried mixtures of tilapia croquette remained suitable for consumption during 240 days of storage.
  • Desempenho produtivo e econômico da Tilápia do nilo (O. niloticus) cultivada em tanques-rede nos períodos de inverno e verão, no rio do Corvo-Paraná

    Filho, L. A. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2008)
    This project aimed to evaluate the performance and economic viability of fish creation in net cages as an alternative to improve life quality of the producers from Corvo River (Parana, Brazil) with minimum environmental impact and great sustainability. The research involved water quality monitoring considering the physic-chemical parameters and evaluation of zootechnical and economical indexes to three storage density in net cages with 100, 150 and 200 fish m-3 in summer and winter cultivation. The species used was Oreochromis niloticus of Thailandese strain, submitted to the sex reversal process. There were used 14,850 juvenile fish in the summer and 8,910 in the winter with 57 and 99 g of weight respectively, and distributed in 6.0 m³ useful cages, being 15 in summer and 09 in winter. The trial period of the summer was 84 days and 140 in winter; however, to final biomass calculation in the summer the weights from 130 days were used. The diet was composed by extruded commercial food, one with 32% PB for the first 30 days and another with 28% PB until the slaughter. The collects of limnological variables were done each thirty days in sub-surface layers, in a longitudinal transect inside the cage. Data of electrical conductivity and pH (digital potentiometers), water temperature daily monitored with maximum and minimum thermometer, dissolved oxygen, and transparency were obtained. The data from the limnological evaluation were submitted to an exploratory analysis through the descriptive statistics, and for the zootechnical and economic evaluation the variance analysis by GLM process were applied, followed by multiple comparison of average using the Tukey test (p<0.05). The physical chemical indicators for both periods were adequate to the limits of the studied specie, except in winter when the average temperature of 20.99°C influenced the results. The production cost structure used in the study was followed by the methodology of Production Operational Cost and as profitability indicators the Gross Revenue and Operating Profit. Analyzing the final zoothecnical performance of two seasons, it was observed that there was no difference (p<0.05) among the three densities in the two periods for final and daily average weight when analyzed separately. Survival rates during the summer showed differences (p<0.05) among treatments, and the lowest rate was for treatment with the highest density (79.99%), while treatments with lower density had the highest rate survivors (94.57%). Comparing the summer and winter period, it was found that there is a difference (p<0.05) for the obtained average weights in the same space-time cultivation. Fish reared in the summer showed a better performance than in the winter (460.40 grams and 367.76 grams respectively) with daily average weight gain of 5.60 g day-1 during the summer, and 3.58 g day-1 in winter. Differences were found (p<0.05) when it was examined the final biomass and feed intake, and the increases were rising as density was increased. The increase in consumption in summer has a direct influence on reducing the apparent food conversion, so that there was difference (p<0.05) for the three densities between the two periods. When it was analyzed the economic indicators in both periods, there was a difference (p<0.05) for all studied variables. The total operational cost (per kg of fish) in the summer period was R$ 2.19 and R$ 1.55 in the winter and the Operating Profit per kg of fish produced was higher in winter (R$ 0.95) than in the summer (R$ 0.31). It was concluded that increased density did not influenced the performance of the fish, therefore, it can establish that a density of 150 fish m-3 for the summer period and 200 fish m-3 for the winter can be used and that the production of the tilapia Nile in cage is economically viable for both periods.
  • Influência da baixa temperatura e diferentes crioprotetores em oócitos e embriões de Colossoma macropomum e Piaractus brachypomus.

    Digmayer, M. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2013)
    The aim of this work was to develop methods for cryopreservation of Colossoma macropomum oocytes and oocytes and embryos of Piaractus brachypomus, as well as to analyze the damages in oocytes and embryos after exposure to cryoprotectant solutions and cryopreservation. Oocytes of C. macropomum were distributed in six cryoprotectant solutions: T1 -methanol 1.6 M + sucrose 0.25 M, T2 - methanol 1.6 M + sucrose 0.5 M, T3 - methanol 1.6 M + trehalose 0.25 M, T4 - methanol 1.6 M + trehalose 0.5 M, T5 - methanol 1.6 M + fructose 0.25 M, T6 - methanol 1.6 M + fructose 0.5 M and T7 - outbreak control. Oocytes were kept in cryoprotectant solutions for 20 minutes at room temperature, fertilized and taken to incubators. A second portion of the oocytes were underwent to slow freezing, stored in liquid nitrogen, thawed, and a part was fixed while the other was fertilized and kept in incubators. The survival probability of oocytes subjected to T1 at room temperature was higher (15.8%). As for survival after hatched larvae, there was no difference between treatments. In the fertilization of oocytes that passed by slow freezing there was not hatching. Morphological preservation was observed in T1 and T2 with cryoprotectant solution containing methanol 1.6 M and sucrose 0.25 and 0.50 M, respectively. The oocytes of Piaractus brachypomus were distributed in eight cryoprotectant solutions: T1 - methanol 1.6 M + sucrose 0.25 M + 50 % L15, T2 -methanol 3.1 M + sucrose 0.25 M + 50 % L15, T3 - DMSO 0.7M + sucrose 0.25 M + 50% L15, T4 - DMSO 1.3 M + sucrose 0.25 M + 50% L15, T5 -methanol 1.6 M + sucrose 0.25 M + Hank, T6 - methanol 3.1 M + sucrose 0,25M + Hank, T7 -DMSO 0.7 M + sucrose 0.25 M + Hank, T8 - DMSO 1.3 M + sucrose 0.25 M + Hank. The embryos frozen at -13ºC were distributed in eight cryoprotectant solutions: T1 - methanol 3.1M + 0.15M PVP + Hank, xvi T2 - methanol 3.1 M + PVP 0.3 M + Hank, T3 - methanol 3.1 M + PVP 0,45M + Hank, T4 - methanol 3.1 M + PVP 0.6 M + Hank, T5 -methanol 3.1 M + sucrose 0.45 M + Hank, T6 - methanol 3.1 M + sucrose 0.63 M + Hank, T7 - methanol 3.1 M + sucrose 0.81 M + Hank, T8 - methanol 3.1 M + sucrose 1.0 M + Hank. Embryos frozen in liquid nitrogen were distributed in four cryoprotectant solutions: T1 - methanol 3.1 M + sucrose 0.45 M + Hank, T2 - methanol 3.1 M + sucrose 0.63 M + Hank, T3 - methanol 3.1 M + sucrose 0.81M + Hank, T4 - methanol 3.1 M + sucrose 1.0 M + Hank. For morphological analysis oocytes and embryos were processed in historesin and oocytes for scanning electron microscopy technique. For oocytes of P. brachypomus kept at room temperature and fertilized treatments that showed embryo development were T5 (methanol 1.5 M, sucrose 0.25 M solution and Hank), 17.3% and T7 (DMSO 0.7 M, sucrose 0.25 M and Hank) 1.8%. In fertilization of oocytes subjected to slow freezing curve there was not embryo development after fertilization. In the morphological analysis it was found that the oocytes of P. brachypomus when subjected to slow freezing in extender solution with methanol 1.6 M + sucrose 0.25 M + solution hank (T5) showed a full zona radiata with regular contour. From embryos that were underwent freezing at -13ºC in T5, 15.3% developed and was significantly higher than in T6 (4.6%), T3 (1.5%), T7 (1.8%) and T8 (1.9%) and there was also embryo development. In other treatments, all embryos subjected to cryoprotectant solutions at a temperature of -13ºC and embryos subjected to treatments in liquid nitrogen resulted in dead embryos. No treatment with oocysts of C. macropomum and oocytes and embryos of P. brachypomus provided maintenance of fertilizing capacity after freezing.
  • Contribuição genética e reprodutiva de piracanjuba (Brycon orbignyanus) submetidos aos sistemas de reprodução seminatural e extrusão.

    Castro, P. L. (Universidade Estadual de Maringá . Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2015)
    Building hydroelectric dams in the course of Brazilian rivers is constantly associated with the large reduction in native fish populations. This action in addition to changing the entire water dynamics, is also a physical barrier that hinders the reproduction of migratory fish, such as piracanjuba (Brycon orbignyanus), strongly impacted species which is currently on the list of fish that are in danger of extinction. To mitigate the damages, a series of public policies were implemented, requiring biological compensation for the use of inland waters for electricity production and restocking, restoring natural populations from the release of alevins, is the most commonly adopted practice. However, if not carefully performed, this practice represents genetic and reproductive risk to populations still present in rivers, given the common loss of genetic variability in the production of alevins in the fish farms. The purpose of this study was to evaluate the influence of extrusion or semi-natural reproductive systems in different breeding (a female to three males and two females to six males), on the genetic and reproductive variability of the obtained progeny. 360 larvae samples were taken (90 larvae for each treatment) as well as a fin fragment from the 24 breeders used, and the genetic variability analyzes performed by PCR (Polymerase Chain Reaction) with amplification of eight microsatellite heterologous primers. 30 alleles were identified ranging from three to four per locus, so that 75% of higher frequency in the parental alleles were also in the offspring, demonstrating the maintenance of allelic frequencies in all treatments. The rates of expected heterozygosity and Shannon found the maintenance of genetic variability, observing the increase of its values in all progenies in relation to their parents. On the other hand, the parental contribution analyzes showed better results for treatments of the reproductive system by extrusion, since apparent relations of reproductive dominance were observed among the males in the semi-natural system, thus the increased number of breeders in the system was responsible for the intensification of this behavior. Moreover, better fertilization, hatching and mortality rates of breeders were observed in the semi-natural system, result associated to injuries caused by abdominal massage in extrusion. Thus, a reduction in the male x female ratio is indicated in the production of piracanjuba alevins in semi-natural system in fish farms aimed at restocking, while in extrusion systems increasing this ratio favors a more homogeneous parental contribution, but it is conditioned to effective participation of all males which can be guaranteed by semen quality analysis.
  • Polimorfismo no íntron 1-PstI do gene do hormônio do crescimento em linhagens de tilápia do Nilo (Oreochromis niloticus).

    Blanck, D. V. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2008)
    Molecular genetics studies are becoming more common in tilapicultura, because the Nile tilapia shows great potential in genetic engineering dedicated to the improvement stocks. With the development of different Nile tilapia (Oreochromis niloticus) strains have been increased the need to identify them, aimed the maintenance and the certification of genetic material quality of improved strains acquired by the producers. Improvement of fish natural growth rates in aquaculture has been widely explored, with gains resulting from improvements in livestock production, nutrition and genetic selection. Due to the high impact of GH in growth regulation and by being involved in several other metabolic functions, the GH gene is a potential target for genetic variation studies and its association with characteristics of fish growth. Thus, this study aimed to: describe the gene intron 1 variability of the growth hormone (GH1) of strains Chitralada and GIFT (Genetically Improvement Farmed Tilapia) from the Nile tilapia through molecular marker PCR-RFLP; study the association of this gene polymorphisms with strains performance characteristics; and seek a molecular marker that could be used in the strains identification and as a selection tool for growth characteristics in genetic improvement programs for the Nile tilapia. 200 animals were used of each strain from witch it was collected fragments of tail fin and the following measurements: total length (CT), standard length (CP), height (AL), width (LA), head length (CC), slaughter weight (PA), fillet weight (PF), fillet yield (RF) and the carcass weight (PC). From collected fin, it was done the genomic material extraction using saturated NaCl (5M). For PCR-RFLP analysis, it was necessary a specific pair of primer design based on the available sequence-reference in the GenBank (access M97766). The generated PCR products were digested with enzyme PstI, with restriction locus located in the intron of the gene GH1. Allelic frequencies, genotypic, rates of heterozygosity, test of the Hardy-Weinberg equilibrium and estatistic F were determined with Popgen 1.31 program. The analysis of the association between the polymorphisms and the performance characteristics were evaluated by the SAS GLM procedure. Duncan test (p <0.05) was used for the variables that showed effect of interaction between genotype and lineage. The three pairs of primers designed amplified satisfactorily in the two strains, producing fragments of 652, 441 and 396 bp. For 652 bp fragment, it was observed the three digestion standard possible for both strains, Chitralada and GIFT, corresponding to the genotypes PstI+/+, PstI+/- and PstI-/-. The genotypic frequencies found for the Chitralada strain were 0.707, 0.282 and 0.011 respectively for the genotypes PstI+/+, PstI+/- and PstI-/- and the GIFT strain, 0.930, 0.075 and 0.005 for the same genotypes. The allelic frequencies obtained in this study (GH1-PstI) show that the PstI+ is dominant in the Nile tilapia. The Chitralada strain (Ho = 0.282) showed greatest heterozygosity to GIFT strain (Ho = 0.065), having therefore a higher variability to the locus in question. The index of differentiation (FST) of the strains was 0.038. The allelic frequencies in the two strains were in Hardy-Weinberg equilibrium. About the association analysis of polymorphisms for production characteristics, there was no correlation only for CC and RF. So the major averages were recorded for animals that carriers the heterozygous genotype. Only to the RF characteristic there was an interaction effect between genotype and strain, to the point that the GIFT strain with homozygous genotype PstI+/+ was 2.72 percent higher than the genotype heterozygous PstI+/-. Within each genotype, the Chitralada strain was higher. With the results obtained here, it is suggested that the combination of performance characteristic of the Nile tilapia strains to the genetic polymorphisms of GH may be due to the effect of the gene regulation of growth hormone. Later detailed identifications of polymorphisms GH1-PstI structure may prove link between RFLPs described and the characteristics controlled by GH, which can contribute to the implementation of MAS in the tilapia genetic programs improvement.
  • Impacto da seleção genética na morfometria e desempenho de tilápias do nilo.

    Zardin, A. M. S. O. (Universidade Estadual de Maringá . Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2015)
    This study aimed to estimate the variance and covariance components, genetic parameters and genetic associations of body traits and performance of Nile tilapia, Tilamax variety, grown in cages, and evaluate responses to selection and genetic evolution between generations, as well as verify the impact of selection on traits, when selecting fish based on daily weight gain. The data set used in the first study contained information of male and female tilapia grown in cages in 2011-12, 2013 and 2014. Estimates were made of variances and covariances components, genetic trends for height and tail width, trunk length, body area, harvest weight, daily weight gain and fillet volume by Bayesian Inference. An animal model considering random effects additive, residual and common family was used in additional to the fixed effects of sex and cages, in single-trait and bi-characteristics analysis. Genetic correlations between traits were positive and higher than 0.82, showing increase in traits, mainly body area and fillet volume. The heritabilities of body traits and performance were of moderate magnitude. Genetic gains were increasing to all traits, specially for daily weight gain, harvest weight, body area and fillet volume with values of 4.15, 4.59, 2.30 and 3.65% per generation, respectively. The selection based on daily weight gain resulted in indirect genetic gains in trait over the generations, changing body shape, increasing body weight with trends changing the fillet weight, as well as in the taking advantage of different cuts to the consumer market. The data set used in the second study contained information of male and female tilapia of Tilamax variety, produced in cages from 2008 to 2015. Estimates were made of variances components for total, standard and trunk length; height and width of the body, body area, harvest weight, daily weight gain and fillet volume by Bayesian inference, using single-trait analysis, in additional to genetic trends and rate of inbreeding. The heritabilities were of moderate magnitude with values between 0.14 to 0.28. The genetic trends showed increases of genetic values over the generations, with annual rates gains of 1.440 cm2 in body area, 12.90 g in harvest weight, 0.04 g day-1 in daily weight gain and 3.317 cm3 in fillet volume, representing 1.27, 2.35, 2.29 and 1.90% per generation, respectively. The rate of inbreeding showed small increment, with value of 0.36% for generation eight. The heritabilities values and genetic variances over the generations showed the genetic progress and response to selection, with the main gains in traits body area, harvest weight, daily weight gain and fillet volumes without reducing the genetic variability and with small increment of inbreeding, which enables genetic gains on future generations.
  • Avaliação do citrato de tamoxifeno e temperatura na inversão sexual da tilápia do Nilo (Oreochromis niloticus).

    Zanoni, M. A. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2011)
    Aquaculture in Brazil has been improving and finding new techniques to improve the quality of fish produced, one of the main problems is the use of steroids in sex inversion of tilapia, despite being a widespread technique and practiced in various regions of the world is increasing concern to environmental liabilities generated by the use of 17 α-methyltestosterone. In this context, this study aims to evaluate the overall use of non steroids in sex inversion of Nile tilapia. The first experiment was conducted to evaluate the influence of citrate tamoxifen on sex inversion of Nile tilapia larvae from two days of life, they were divided into an experimental design of five treatments and three replicates, and fed diets with different amounts of citrate tamoxifen: 0, 25, 50, 75 and 100 mg kg-1 of feed. After 28 days of treatment, the larvae remaining in each treatment were counted and transferred to water tanks of 500 liters which were fed a diet containing 28% crude protein for 60 days. After this period the fry were sexed by the "squash" method. The survival 75.5 ± 5.74, 73 ± 4.76, 66 ± 11.19, 76.5 ± 4.12, 75 ± 3.46 and average percentage of male individuals 62.5 ± 5, 70 ± 8.1, 60 ± 8.2, 70 ± 0.0, 62.5 ± 9.5 for treatments 0, 25, 50, 75 and 100 mg of citrate tamoxifen kg-1 diet, respectively, showed no statistically significant differences. The number of gonads in each subject experienced a significant reduction in the treatments with 75 and 100 mg of citrate tamoxifen (89.3 and 79.3 ± 0.527 ± 0.378) when compared with treatments 0, 25 and 50 mg of citrate tamoxifen (98, 9 ± 1.0, 97.6 ± 1.0 and 94.5 ± 1.0, respectively), the histological structure of female gonads did not differ and ovaries in all treatments showed well-defined and oocytes at various stages of maturation. The second experiment evaluated the effects of temperature 28, 30, 32 and 34°C and control (28ºC + ration plus 60 mg of 17 α-methyltestosterone) in sexual inversion, survival and presence of deformities in Nile tilapia. The results showed a statistical difference between the proportion of males, with a temperature of 32 and 34°C and control (91 ± 0.71; 96 ± 0.59 and 98.33 ± 1.0%, respectively) showed better results than those obtained for 28 and 30 degrees treatments (71 and 82 ± 0.29 ± 0.33%). Survival: 90.49 ± 2.32, 88.20 ± 2.04, 85.43 ± 1.58, 82.16 ± 1.63 and 90.74 ± 2.28% for temperatures 28, 30, 32 and 34°C, respectively, showed no statistical differences, but there were differences in survival between the control and treatments 32 and 34°C. In the analysis of radiographs was not possible to observe the presence of morphological changes in fish subjected to different treatments. With this experiment it was concluded that temperatures of 32 and 34°C larvae were able to genetically masculinizing females, and that there was no increase in mortality and in deformities presence that can be attributed to treatment. This technique is an alternative to the use of steroid hormones. The third experiment was conducted in order to describe gonads of Nile tilapia fingerlings (Supreme) with 75 days of age, using as a tool cytological techniques, structural and ultrastructural. Cytological technique gonads were stained with carmine acetate pressed between slide and coverslip and observed under light microscopy. To structural prepare gonads, after processing, were cut in microtome at thickness of 5 mm, stained with hematoxylin-eosin and observed under light microscopy. At the ultrastructural method, gonads were photo documented in a scanning electron microscope FEI QUANTA 200. The structural and cytological preparations allowed the visualization of the ovaries of oocytes, cell boundaries, nuclei and nucleoli associated. In males the cytologic preparations did not allow a clear identification of the structures, but in preparing structural testicular sperm was possible to visualize cysts, Sertoli cells and the beginning of the formation of seminiferous tubules. The scanning electron microscopy, used to visualize surface allowed, after the fracture of the gonads, to observe internal structure, such as spermatogonia, oocytes and collagen fibers. The results showed that all three techniques were efficient in distinguishing the sex of the individual, allowing observation and comparison of the structures present in the gonads.
  • Avaliação de Homeopatila RS, em tilápias do Nilo, Oreochromis niloticus (Linnaeus, 1758), fase de larvicultura, no desenvolvimento, proporção sexual e histologia de brânquias e fígado.

    Zabott, M. V. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2006)
    The Nile tilapias, Oreochromis niloticus, natives from Africa, are fishes worldly cultivated and they are characterized by great rusticity and adaptability to the most several cultivation systems. Considering the reproductive aspect they are precocious and males are larger than females. Exclusive populations of males are desired in this species due to the fact of having better performance and uniformity. In Brazil, the majority of the market demands for male fingerlings and they are obtained by sexual reversion using steroids hormones. The objective of this paper was to evaluate the effects of the homeopathic nucleus Homeopatila RS. This compound has as base the iodine, male gonads and Pituitary gland extract dinamization, so, an experiment were accomplished, with Nile tilapias during the period of gonadal differentiation for: a) evaluate the development and sexual proportion; b) investigate gills and liver fingerlings histological alterations. There were three distinct treatments: a) control, alcohol 30ºGL (C); b) hormonal, 17 a-metiltestosterone (H); c) homeopathic, Homeopatila RS, in hidroalcoholic solution (HH). The experiment was realized at the aquaculture center of Universidade Paranaense-UNIPAR, Umuarama-PR, from February to April 2006, for 45 days. It was used 4.800 post-larvae, distributed in 12 water boxes (500L). Each treatment had 4 replications totalizing twelve units. The results showed that there is not an effect (p>0.05) correlation between sexual proportion and use of Homeopatila RS, when observing the male and female gonads frequencies in relation to the control group. The hormonal treatment, showed a higher significantly frequency male gonads and intersex in relation to the other treatments, being absent the females frequency in this treatment. The animals? performance data analysis revealed significant differences 13 among the treatments (p < 0.05). The homeopathy treated group had a higher survival rate and a lower liver-somatic index, when compared with other groups. The histological analysis showed a significant difference (p<0.05), for the medium values of hepatic alterations, to lipidic inclusion, being lower than other treatments. There were not differences (p>0.05), for gills histological alterations. As conclusion, the homeopathic nucleus Homeopatila RS, added in Nile tilapias ration, during the gonadal phase differentiation, did not induce a sexual proportion alteration, in terms of masculinization, but showed a positive effect in the survival. The animals treated with homeopathy had smaller hepatic lipidic inclusion compared with other treated groups
  • Avaliação genética e de efeitos ambientais em características reprodutivas de tilápia do Nilo.

    Yoshida, G. M. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2014)
    The aim of this work was to investigate the effect of three different age classes and different reproductive environments in Nile tilapia female performance, as well as, to estimate the genetic parameters for reproductive traits using the Bayesian inference methodology. The data set contained information from 451 female Nile tilapia evaluated in two different environments in Maringá, Paraná State and in an environment in Alfenas, Minas Gerais State. The spawning observation was carried once a week from October 2012 to March 2013, corresponding to 23 weeks of evaluation. For statistical analysis it was used the procedure Proc Genmod for the SAS statistical program and for the estimation of genetic parameters the computer program MTGSAM Threshold. The traits studied were spawning success, number of spawning, spawning frequency and volume of eggs/female. In statistical analyzes, Local 2 was inferior to the other Locals for the most of traits when using female of age 2. Statistical differences were not observed between Age 1 and 2 for the same Local of evaluation. The Age 3 present at Local 3 showed superior results when compared with female of age 2 for all traits. The heritability estimates were 0.14, 0.16, 0.53 and 0.02 for spawning success, multiple spawning, spawning frequencies and volume of eggs respectively and repeatability obtained for egg volume was 0.28. The results indicate that older females have higher reproductive performance than female of age 1 and 2 and should avoid the use of animals in individual hapas. Heritability estimates show genetic gain if used reproductive traits as selection criteria.
  • Manejo alimentar e retorno econômico de tilápia do Nilo (Oreochromisniloticus) cultivada em tanques-rede, no período de inverno.

    Tardivo, T. F. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2011)
    This study aimed to evaluate the performance and economic viability of farming Nile tilapia (Oreochromis niloticus) in cages in the winter in the Corvo River, Paraná - Brazil. The research involved the evaluation of biological indices, economic return and investment analysis of three feeding strategies in the winter season of animals. The species used was the Nile tilapia, Oreochromis niloticus GIFT strain, sexually reversed. 12,600 juveniles were used with average weight of 45 grams, divided into cages of useful 6.0 m³ . The experimental period was 180 days. Extruded feed was used with 35% CP (4mm) and / or 30% CP (4mm and 6mm), used according to the weights and the management adopted. In the first food management (FM1) was feed 30% CP (4 and 6mm). In the second feed management (FM2) was used a diet with 35% CP (4 mm) to 150 to 200 grams and a diet with 30% CP (6mm) to the end of fattening. In the third feed management (FM3) with 35% CP diet (4mm) to 350 to 400 grams and diet with 30% CP (6mm) to the end of fattening. Samples were collected monthly to monitor consumption. For performance evaluation data were applied analysis of variance by GLM procedure, followed by multiple comparison of mean adopting the Tukey test (p <0.05). The average water temperature of the experimental period was 22.0 ° C below the comfort zone of the species. The cost structure of production used was developed considering the methodology of Production and Operating Cost and profitability indicators of Gross Revenue, Operating Income, and Gross Point Leveling. From the preparation of cash flow for 60 months were obtained the following indicators: Internal Rate of Return, Net Present Value, Benefit-Cost and Capital Recovery Period. The discount rate used was 0.07% per month. Analyzing the production performance of the period, there was no difference (p <0.05) between feeding strategies for the final weight, weight gain, daily weight gain, feed conversion and productivity. Survival rates were different (p <0.05) between feeding strategies, with the best results for FM1 (88.90%). The total consumption of food also differed (p <0.05) between the managements. The high feed conversion influenced by treatments influenced the Operating Costs Effective leading to a higher total production costs. The lowest total operating cost was found in the FM1 (R$2,66). Operating income per pound of fish produced was similar to the FM1 and FM2 (R$0,07 / kg fish). The loss FM3 obtained at the end of the cycle (R$ 0,05). The internal rates of return obtained by feeding strategies 1 and 2 (1.051 and 1.044%) were above the pay rates of savings. The FM1 proved to be the best option in the winter.
  • Suplementação de semente de Perila (Perilla frutescens) como fonte de ácido graxo ômega-3 em dieta para tilápia do Nilo.

    Santos, H. M. C. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2011)
    The Nile tilapia (Oreochromis niloticus) is a fish of great current interest in fish farming, and the second group of freshwater fish cultivated over the world, behind only the carp. Freshwater fish such as Nile tilapia normally present low concentrations of n-3 VLC-PUFA content, including compared with sea fish. This aspect is related mainly the different food between the species and physiological changes. In freshwater fish, linoleic acid (LA, 18:2n-6) and alpha-linolenic acid (LNA, 18:3n-3) are metabolized by the same sequential desaturation and elongation enzyme systems, which results in the production of long-chain PUFA n-3 and n-6 series. Perilla frutescens is a plant that belongs to the Lamiaceae family native to Asia, whose seeds are a traditional source of oils produced in Korea, India, China, and other Asian countries. Its oil has the highest proportion of alpha-linolenic acid (LNA) among the vegetable, representing approximately 60% of its total fatty acid content. Thus, supplementation of perilla seed in the diet of tilapia becomes an alternative to improve the concentration of n-3 PUFA in muscle tissue. This study evaluated the effect of dietary supplementation of perilla Nile tilapia on the fatty acid composition of muscle tissue as a function of feeding time length. Were used 400 Nile tilapia (Oreochromis niloticus) with initial live weight 245 ± 10.96 g, distributed in eight net cages. The tilapia received for 60 days a diet with perilla seed ground (5%) and one control, with soybean oil. At the beginning of the experiment and every 15 days were analyzed the composition of proximal muscle tissues of tilapia and quantification of fatty acids (mg / g total lipids) by gas chromatography. Among the experimental diets and during the feeding period, the values of total lipids in muscle tissue of tilapia did not differ (p> 0.05). The fatty acid composition of muscle tissue of tilapia was affected by diet. According to the quantitative analysis of fatty acids, were observed an increase in n-3 PUFA, especially the LNA during feeding with the diet supplemented with perilla, proving the influence of diet on the lipid composition of fish. The n-6/n-3 ratio during the period of feeding the diet with perilla has from 11.57 (0 days) to 3.04 within 60 days of experiment. Through the inclusion of perilla seed in the diet of Nile tilapia, verified the incorporation of n-3 fatty acids and an improvement in n-3/n-6 ratio. Therefore, supplementation of perilla contributed to raising the nutritional quality of the total lipids of muscle tissue of Nile tilapia.
  • Polimorfismos no gene do hormônio do crescimento associado a características de crescimento de Tilápia do Nilo.

    Rodriguez, M. P. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2014)
    The growth hormone gene (GH) has been a point of study for many researchers because it has been shown that it acts in various physiological processes. Molecular techniques such as sequencing have enabled access to the genomic structure information of GH gene and its polymorphisms, some of these correlated with improved performance and/or production. Tilapia have two GH called GH1 and GH2 their genomic sequences are in the GENBANK database with access numbers of M97766.1 and M97765, respectively, when done the alignment of these sequences we found a high homology. However, there is the repetition of a microsatellite (CTGT) located at two base pairs of the exon 2, the GH1 has seven replications and GH2 has six replications. A pair of specific primers for the GH1 and GH2 genes that amplify a commum region, where the only expected difference are the four base pairs relating to repetition (CTGT) at least, previously described in GH2, shows a difference of approximately 50bp tilapia in some individuals of tilapia, thus defining two types of individuals when using the primer pair, those with a single fragment of 650bp called GHbs (GH single band) and those with two fragments 650pb and 700pb GHbd (GH band double). Given this observation the research objective was to characterize polymorphisms not yet reported GHbs and GHbd by sequencing technique for varieties of GIFT tilapia, Thai, Bouaké and some of its crossings and calculate the frequencies of these polymorphisms . From the results of sequencing GHbs came to be called GH/Ho individuals who are homozygous with the same number of repetitions (CTGT) in GH1 and GH2 and GHbd as GH/He individuals who are heterozygous with different number of repetitions (CTGT) in GH1 and GH2. Thus, the other objectives were to evaluate the relationship between the polymorphisms GH/HO and GH/He with the performance characteristics polymorphisms, assessing the growth of tilapia GIFT x Thai in a period of 150 days and analyze the hyperplastic and hypertrophic growth of white muscle at 30-60-90 and 120 days of age tilapia, being collected right lateral muscle which was insert paraffin for semi-serial cuts and hematoxylin-eosin staining. The results of sequencing revealed that, when made the sequences aliggnments of genotypes GHbs and GHbd these have mutations as transversions, transitions and deletions when compared to the sequences of the GH1 and GH2 genes. It was also described that individuals can be either homozygous (GH/Ho) or heterozygous (GH/He) with respect to the number of the microsatellite repeats (CTGT) in GH1 and GH2. The genotype frequencies in Thai variety and crossing Thai Thai x GIFT showed 50% of GH/HE and GH/Ho, GIFT of fifth generation from a breeding program showed 90% of GH/Ho and crossing GIFT x Bouake (GXB) found up 100% of individuals GH/He. The results of the morphometric and performance was a significant effect of amplification pattern GH/He for final weight (FW), weight gain (WG), total length (TL), head length (CCAB), head weight was observed (PCAB), weight of gutted fish (PPevis) and weight of skinless fillet (pFILE). Histological evaluations of white muscle fibers of the genotypes showed no significant difference in the frequencies for most ages considered. We can conclude that both GH1 and GH2 may have 6 or 7 repeats of microsatellite CTGT, other low-frequency polymorphisms can be found in the studied region of the GH gene in variety GIFT and frequencies of GH/HO or GH/He may be associated with variety. Evaluations of performance the GH/He individuals showed significant differences for some features, however, it takes a study to examine whether there is change in the amino acid or regulatory regions of the GH gene, yet in the growth of white muscle there are no differences between the polymorphisms.
  • Análise de parâmetros físico-químicos e biológicos no sistema intensivo de produção de tilápia do Nilo.

    Pires, T. B. (Universidade Estadual de Maringá . Centro de Ciências Agrárias . Programa de Pós-Graduação em Zootecnia, 2014)
    This work was performed at the Crow River, a tributary of Rosana reservoir (RP/SP) located in the area between the towns of North Diamond (PR) and Terra Rica. 18,000 juveniles post-reversed for male of Nile tilapia (O. niloticus), from the variety GIFT were used. From these animals the biomass data at intervals of approximately thirty days were collected in the summer period, to determine the feeding management. The evaluation of limnology, temperature, dissolved oxygen, oxygen saturation, electric conductivity and transparency were determined in situ. For these were used a sampling interval of about fifteen days and were evaluated at three levels of the water column; while the evaluation of the levels of total nitrogen, orthophosphate and nitrate occurred at intervals of thirty days and in two levels of the water column. Limnological data were collected at an interval of four hours between each repetition in the day. The collection of aquatic macroinvertebrates occurred through a method of natural colonization, called bio collector, made from a plastic net with a capacity of five kilos and using as substrate 15g of Cattail (Typha sp.), 10 cm of plant bush and about 450g of crushed stone and gravel, with six replicates for each point. One triplicate of bio collectorswas exposed for about 15 days and the other three for about 30 days from the date of its implementation. The data of the limnological variables were subjected to descriptive analysis and variance (Anova) and means were compared by the Scott-Knott test at 5% probability. A statistical analysis using the Poisson distribution with log link function to the data obtained by counting identifiedaquatic macroinvertebrates was applied. The number of individuals and the richness were used to evaluate: collection points established; transects formed with the deployment of cages; the effect of stocking densities of fish in cages and the exposure time of bio collectors. The system of cultivation in cages caused a significant variation (P<0.05) in oxygen content and pH. On average in the transect without cages the saturation by oxygen, and the oxygen dissolved in water is 2.9% and 0.24 mg/L to higher than the available transects in cages, with significant difference (P <0.05) between these transects. But even with the effect of fish farming indexes of water quality evaluated have not breached the levels imposed by Resolution No. 357/2005 of Conama, indicating that the environment has the capacity to assimilate mitigating the impact of fish farming organic load imposed by the activity in function of waste from feed and fish excreta. The sampling method of benthic macroinvertebrate communities was more efficient in the environmental monitoring than thelimnological variables, confirming that the increase of organic matter increases the density of these organisms, especially the group of Oligochaeta, Hirudinea and Gastropoda. These results demonstrate the importance of studies in this area to define more precisely the methodological procedure and studies aboutthe responses of groups of benthic macroinvertebratesin function of aquaculture production activities.
  • Avaliação da diversidade genética e do manejo reprodutivo em pacu, Piaractus mesopotamicus.

    Povh, J. A. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2007)
    In many Brazilian Rivers it has been observed a decrease and even a disappearance of many fish species caused by factors as pollution, building dams and over fishing. Among these species, the pacu (Piaractus mesopotamicus) nowadays is barely found in some rivers, for example, in the Paranapanema River. As a fonn to outline the impacts on fish's populations, the restocking technique has been very used in Brazil. However, this practice has been realized, in general, without any scientific support. Facing this scenery, any action that seeks the environment recovery should look for the monitoring by scientific ways not basing in suppositions. Among methodologies for this aim, the molecular markers are tools that can be used to recognition and genetic characterization of stocks (native and broodstocks) and fish that will be get free in the environment. So, the works presented here evaluated the genetic diversity of Piaractus mesopotamicus collected in the middle of Paranapanema River, of fish farming broodstocks with restocking purpose, and also offspring's obtained by extrusion and semi-natural reproductive systems. For these evaluations the molecular markers RAPD (Random Amplified Polymorphic DNA) and microsatellite were using, both based on PCR (Polymerase Chain Reaction). The results showed a lower genetic variability of stock in relation to population, promoted by founder effect of this stock and/or due to different origin of fish that formed the stock. However, the moderate genetic differentiation and high Nm obtained indicate that populations and stock presented a similar genetic pool. As for the reproductive systems, a great genetic variability reduction was observed in the offspring from extrusion reproduction system in relation to the semi-natural system. Although this last system has presented dominance of some reproducers, due multiple patemities existence, there was a genetic Variability maintenance of offspring in relation to reproducers.
  • Diversidade genética de Brycon orbignyanus em sistema reprodutivo seminatural.

    Barrero, N. M. L. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2007)
    Several ecological and climatic factors and especially those related to man's actions have led to the disappearance of piracanjuba (Brycon orbignyanus) natural populations. For the importance of the ecosystems in which it is located and by its qualities of fast growth and good adaptation to controlled environments, in the last years the producer's interest in the use of such migratory species has increased, aiming the production and the participation in conservation and stock enhancement programs. In the implementation of management and stock enhancement programs as conservation strategies, the genetic monitoring, the evaluation of reproductive procedures and the scientific support of different areas are necessary to obtain a correct maintenance and a greater objectivity of such programs. The purpose of this study was to evaluate the influence of the reproductive and semi-natural systems in the genetic diversity and the parental contribution of B. orbignyanus offspring's destined to stock enhancement programs of the Paranapanema River with the RAPD (Random Amplified Polymorphic DNA) and microsatellites molecular markers. The results showed an increase of the genetic variability when an equal proportion of sex was used, possibly due to the effective broodstock number used in the mating and the semi-natural reproductive system. The semi-natural system allowed the preservation of the reproducers in the reproductive process. The occurrence of multiple paternities and the reproductive dominance was verified. These results provide information's that will contribute to the development of management models in B. orbignyanus, ensuring a correct genetic and a reproductive monitoring that are important for a safe conservation of the specie.
  • Parâmetros genéticos para características de desempenho e morfométricas em tilápias do Nilo (Oreochromis niloticus).

    Oliveira, S. N. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2011)
    The aim of this study was to estimate the (co) variance and genetic parameters for performance traits (weight and average daily weight gain) for two generations of Nile tilapia (Oreochromis niloticus), GIFT strain belonging to Breeding Program State University of Maringá. We used 3,918 animals, the univariate and bivariate were taken from the animal model using Bayesian inference by the application program MTGSAM (Multiple Trait Gibbs Sampler using in Animal Model). The proposed model includes the effects cages, generation and gender, common hatchery environments (random) and nursery environment (nalev) in addition to additive genetic effects. For analysis, we used the scheme of the long chain of 500,000 cycles, discard sample of 50,000 cycles and sampling intervals of ten cycles. For the purposes of cages, year of birth and sex, it was considered as having flat distribution for the additive genetic and common environment hatchery and nursery, we have assumed the distribution of inverted chi-square for univariate and range reversed to the bivariate analysis. Estimates of heritability coefficient in univariate for weight, weight gain, total length, standard length, height, width and head were 0.15, 0.19, 0.23, 0.19, 0.17, 0 , 15, and 0.17, respectively. The genetic and phenotypic correlations were found in medium to high magnitude ranging from 0.68 to 0.95. The values of Spearman and Pearson correlations for the ratings of the breeding value of morphometric features in the speed of weight gain ranged from 0.58 to 0.98 to 0.63 to 0.99, respectively. The values of genetic gain, the effective population size and inbreeding coefficient for the second generation (G2) were 2.6%, 94 and 0.005, repectively, and the third generation (G3) were 8.1%, 124 and 0.004, repectively.
  • Interação genótipo X ambiente para peso vivo e modelagem estatística para seleção genética em tilápias do nilo (Oreochromis niloticus).

    Oliveira, S. N. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2013)
    This study evaluated the existence of genotype x environment interaction for bodyweight in Nile tilapia (Oreochromis niloticus), GIFT range between three cities indifferent regions in the Paraná state. The data set consisted of 1,132 animals, males and females, born between November 2011 and February 2012. Analyses were performed using Bayesian inference, considering an animal model that included fixed effects of sex, linear and quadratic covariate of fish age (in days), in addition to the effects considered random, and the additive genetic and common environment hatchery (c) and nursery (w) , where the weight was treated as a different trait in each of the regions. The results of heritability were high for univariate models, being 0.71 , 0.72 and 0.67 for the cities of Palotina (PL) , Floriano (FL) and Diamante do Norte (DN) , respectively , the results of heritability for the two-trait analyzes showed similar values. Genetic correlations estimated in vicariate analyzes were weak with values between 0.12 PL-FL,0.06 for PL- DN and 0.23 for FL-DM. The Spearman correlation values were low, indicating change in ranking in the animals selection in different environments understudy. There was heterogeneity of phenotypic variance between the three regions and heterogeneity of residual variance between PL and DN. The direct genetic gain was greater for DN region with the value of 281.35 g of weight gain per generation, followed by FL with 198.24 g per generation and finally PL with 98.73 g per generation. The indirect genetic gains ranged from 7.77 g per generation between DNand PL to 74.66 g per generation between FL and DN. Eight statistical models were used to check what best describes the average daily weight gain (ADG), in order to make the best selection in animals subjected to genetic breeding program of tilapia(Oreochromis niloticus), variety GIFT, and the data set consisted of information from2,615 animals, from the fourth generation of selection (G4) . The analyzes considered the animal model that included fixed effects of sex, linear and quadratic covariate offish age, in days, in addition to additive genetic effects. The models were modified to include or not maternal genetic effect (m) and common hatchery environments (c) and nursery (w) . The results of heritability were considered the average for most models,M2 = 0.24, M4 = 0.23, M5 = 0.28, = 0.30 M6, M7 and M8 = 0.33 = 0.36 and high for models M1 = M3 = 0.83 and 0.79 . The Bayesian deviance information criterion (DIC)was lower for M1 (DIC = -282.59) and higher for M4 (DIC = 1754.57) . The criterion of log marginal density for Bayes factor agreed with the DIC to the lowest value at which M1 = 585.29 and the highest value presented for this criterion was for M5 =1837.37.
  • Utilização de crioprotetores intra e extracelulares em embriões de pacu (Piaractus mesopotamicus).

    Neves, P. R. (Universidade Estadual de Maringá. Centro de Ciências Agrárias. Programa de Pós-Graduação em Zootecnia, 2008)
    This study aimed to develop a methodology of pacu (Piaractus mesopotamicus) embryos cryopreservation and to analyze the injury cells caused in these embryos after the cryoprotectants intracellulares, methanol and ethylene glycol applications, in concentrations of 7%, 10% and 13% with the addition of an extracellular cryoprotector, the sucrose 0,1 M. After the exposure 10 embryos were processed in historesin and the morphologic preservation was evaluated in agreement with three categories considering the characteristics: chorion, yolk, yolk syncytial layer and germ layers. The used cryoprotectors did not alter the chorion preservation. The sucrose had significant effect on yolk preservation when compared to the intracellulares cryoprotectors. A higher acidophilia of the yolk granules indicated a positive effect only when the sucrose was used and with the interaction of cryoprotector intracellular and sucrose. There was positive effect with the use of the sucrose for the number and size characteristics of nuclei present in the yolk syncytial layer with significant effect of the interaction between intracellular cryoprotector and sucrose on the nuclei size. The intracellular cryoprotector ethylene glycol allowed a higher differentiation of the germ layers when compared to the methanol, but there was not any significant difference in using sucrose. The association of the ethylene glycol in the concentration of 7% with sucrose showed to be the best cryoprotectors combination to the preservation of the yolk and germ layers of Piaractus mesopotamicus. To analyzed embryonic morphology a total of 20 embryos/treatment were fill and frozen and after thawing three embryos, on average, resultants of that process were included in historesin, stained with hematoxilin-eosin and analyzed under optical microscope (OM). A straw/treatment containing embryos was thawed and maintained in incubator with the objective in order to accompany the development, not resulting in embryos outbreak. Samples of two embryos submitted to the treatments with methanol and ethylene glycol in the concentration of 10% associated or not with sucrose and the treatments water and water with sucrose frozen and not frozen were processed and analyzed through scanning electron microscopic (SEM). In spite of the embryos presenting the typical structures of the phase such as chorion, yolk, yolk syncytial layer and germ layers they were altered in 100% when the embryos were analyzed under OM and SEM. The chorion became irregular and broken; absence of individualization of the yolk granules; yolk syncytial layer presented shape thickness and irregular size and the blastoderm presented altered nuclei in the shape and sometimes lacking, located in atypical areas or absent in some embryos. No treatment was effective for embryo preservation and consequent appearance. The used protocols did not avoid the intracellular ice formation resulting in serious morphologic alterations during the freezing and thawing processes, making unfeasible the embryos of P. mesopotamicus.

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