Determination of the best feeding ratio in Huso huso meat production cultured in fiber glass tanks

Abstract

A two-phase random growth test was conducted to evaluate the effects of feeding rate on growth performance, food conversion ratio (FCR), specific growth rate (SGR), feeding efficiency and price index of reared Huso huso fingerlings in fiberglass tanks (2x2x0.53 cm). Rearing conditions such as diet, dissolved oxygen, light, water flow, fish density and feeding frequency were kept similar for the tanks. In the first phase, 180 fingerlings with a mean weight 867.86±17.42g were fed for 100 days in four treatments and three replications at feeding rates 1, 2, 3 and 4 percent of their biomass. In the second phase, also four treatments and three replications were applied to 84 Huso huso with a mean weight 2096.1±35.6g. In this phase, the fish were fed for 125 days with 0.75, I .5, 2.5 and 3 percent of their biomass. During rearing period, water temperature was 25.52±1.78 and 14.82±0.48 degrees centigrade and dissolved oxygen was 7.6±0.3 and 7.89±0.18 mg/lit, for the two phases respectively. The fishes were fed four times daily with a diet containing 40% protein, 13% fat and 9.9% ash. All treatments induced fast growth in the fish, but feeding ratios were different in their effects on the growth (P<0.05). Weight gain percentage, specific growth rate (SGR), food conversion ratio (FCR), feeding efficiency and price index indicated that lower feeding ratios were more effective in causing fish growth (P<0.05). So, increase in feeding ratio directly increased daily food consumption (D.F.C) and negatively affected the feeding efficiency, food conversion ratio, specific growth rate and price index (P<0.05). The results showed that in phase one, when the fish were given food as much as two percent of their body weight, one unit of meat was produced by consuming 1.92 units of food. In the second phase, feeding fish with 0.75 percent of their body weight resulted in producing one unit of fish meat per 1.82 units of food consumed. Also, in the two phases, application of higher than 50% feeding ratio increased costs while no significant trend in fish growth was detected. It can be concluded that regarding the water temperature, the optimal feeding rate for fishes weighing 850 to 1900 grams and those weighing 2050 to 3300 grams are 2 % and 1 % of body weight, respectively.