Identification of key nutrients for gonadal development by comparative analysis of proximate composition and fatty/amino acid profile in tissues and eggs of Chinese sturgeon (Acipenser sinensisGray, 1835)

The present study was conducted to characterize the proximate composition and fatty/amino acid profile in muscle, liver and gonads obtained from farmed male and female Chinese sturgeon (Acipenser sinensis) with gonad development at stage II, and to discern the key nutrients for gonads by comparing the nutrients between tissues and between fish at different gonad stages. Chinese sturgeon were reared in an outdoor circular cement pool at temperatures ranging from 8°C to 26°C, and fed with 70% artificial diets and 30% frozen forage fish at a feeding rate of 0.2%–1.5% body weight according to the water temperature. Three male and three female A. sinensis were sampled for analyses. Results showed that the lipid content in gonads was significantly higher than in other tissues in both males and females (p < .05). The protein content in male and female gonads was significantly lower than that in the muscle (p < .05). Total content of mono-unsaturated fatty acids (MUFA) in females was significantly higher than in males (p < .05), while the total content of n-6 PUFA in females was significantly lower than in males (p < .05). Palmitic acid (C16:0) and oleic acid (C18:1n9) were the major saturated fatty acid (SFA) and MUFA, respectively, in both females and males. The contents of C18:2n6, C20:4n6 (ARA), C18:3n3 and C22:6n3 (DHA) in male gonads were significantly higher than in females (p < .05). The contents of ARA, EPA and DHA in gonads were lower, possibly playing a pivotal role in gonad development. Comparing the nutrients of ovaries in broodstocks at stages III and IV and the eggs at stage IV, the present study suggests that the lipid and fatty acid profile in fish is vital to the gonad development and that proper improvement of lipid nutrition in the broodstock diet to provide sufficient energy and essential fatty acids would be beneficial for the gonad development of Acipenser sinensis.