Comparative survey on effect of Artemia urmiana enriched with vitamin C and HUFA, daphnia and formulated feed as food on growth, survival and resistance of sturgeon larvae ( Acipenser persicus and Huso huso)

Abstract

High mortality frequently occurs in larval mass production of Persian sturgeon fish, Acipenser persicus. Nutritional deficiencies in live food, Artemia urmiana nauplii, fed to larvae could be a reason. A series of experiments was carried out to evaluate the effects of nutritional enrichment of Artemia by oils in different concentrations with or without different levels of vitamin C during two enrichment periods (12 and 24h) on survival, growth rate and salinity tolerance in Persian sturgeon larvae reared in tanks after 20 days. Four types of oils (ICES30/4, sturgeon ovary, cod liver, and linseed oils) were evaluated. HUFA oil source with or without vitamin C did not affect the growth rate of Persian sturgeon larvae. Nevertheless, survival rates and chemical compositions were significantly improved (P<0.05) only in fish larvae fed Artemia enriched HUFA oil supplemented with vitamin C. ICES30/4 was the best oil source for improving the chemical composition including fatty acids in Persian sturgeon larvae only when it was supplemented with vitamin C. Lower levels of vitamin C (less than 30%) and longer enrichment period (24h) were more effective (P<0.05) in improving on chemical composition of sturgeon fish larvae. When the sturgeon larvae were exposed to salinity test, those fed with HUFA enriched Artemia showed tolerance only up to 6 ppt while those fed HUFA+vitamin C enriched Artemia demonstrated high tolerance (≥ 90% survival) up to 12 ppt for 120h. Although the enrichment of Artemia urmiana with 300 ppm ICES30/4 and 30% vitamin C gave the best salinity tolerance at 12ppt (100% survival), the enrichment with 300 ppm sturgeon ovary oil and 10% vitamin C was economically affective in increasing the salinity tolerance of Persian sturgeon larvae (98 % survival).