饲料脂肪源搭配对施氏鲟雌鱼繁殖性能和血清性类固醇激素的影响

以鱼油和玉米油作为脂肪源, 配制4种等氮饲料(蛋白含量38%, 脂肪含量12%~13%), 使脂肪酸中高度不饱和脂肪酸(n-3HUFA)的比例分别达3.1%、2.5%、1.9%、1.3%(分别简称SL1、SL2、SL3和SL4), 以其饲喂处于性腺发育Ⅲ期的施氏鲟(Acipenser schrenckii)亲鱼5个月, 研究不饱和脂肪酸对其繁殖性能及性类固醇激素水平变化的影响。结果表明, 经过 5个月养殖, 施氏鲟亲鱼平均体质量增加14.5%, 经过低温刺激及升温处理至产前体质量下降6.8%, 各组之间差异不显著(P>0.05); 饲料中n-3HUFA和n-3PUFA水平对繁殖性能有不同程度的影响, SL1组和SL2组亲鱼的成熟度和仔鱼成活率高于SL3和SL4组, 而仔鱼畸形率显著低于SL3和SL4组(P<0.05); SL1组极化卵卵径显著高于其他组(P<0.05), 平均产卵量高于其他组, 但各组之间差异不显著(P>0.05); 各组之间的受精率、孵化率差异不显著(P<0.05); 各饲料组间血清E₂和血清T含量差异不显著(P>0.05)。本研究表明, 使用混合鱼油作为饲料脂肪源, 效果好于单一使用鱼油或玉米油, 同时鱼油的需求比例大于玉米油, 建议n-3 HUFA的适宜添加量在2.5%左右, n-3 PUFA最适需要量需要进一步研究。

Effects of fat source matching in broodstock diets on reproductive performance and serum sex steroid levels in Amur sturgeon, Acipenser schrenckii

 The effects of unsaturated fatty acids content in Amur sturgeon(Acipenser schrenckii) broodstock diets on reproductive performance and serum sex steroids levels were studied. Four groups of 48 female broodstocks, with an average body weight of (18.24±2.44) kg, were fed four artificial formulated diets containing 3.1%(SL1), 2.5%(SL2), 1.9%(SL3) and 1.3%(SL4) of n-3HUFA by adding different proportions of refined fish oil and corn oil for a period of 5 months from stage III of gonad development. Their reproductive performance, serum E₂ and T were evaluated. The results showed that after the Amur sturgeons were fed the diets for 5 months, their average body weight increased by 14.5%, while their average body weight dropped by 6.8% after winter and heating processing, with no significant difference between the trial groups (P>0.05). Different n-3 HUFA and n-3 PUFA levels in feed had different effects on reproductive performance. The maturity rate and larval survival rate of the SL1 and SL2 groups were significantly higher than those of SL3 and SL4 group (P<0.05), while the rates of abnormalities and deformities were significantly lower than that of the SL3 and SL4 group (P<0.05). The diameter of the polarization egg of the SL1 group was significantly higher than that of the other groups (P<0.05), while average fecundity was higher than other groups, but not significantly (P>0.05). The fertilization rate and hatching rate were not significantly different among the trial groups (P<0.05). The serum E₂ level of each group was significantly higher than that before feeding (P<0.05), while the serum T level of each group decreased differently compared with before feeding (P>0.05); however, no significant difference was found among the trial groups (P> 0.05). This study indicated that the mixed oil is better than single fish oil or corn oil as a feed source of fat, the effect of fish oil is greater than that of corn oil in the feed at the same time, and the appropriate requirement forn-3 HUFA is approximately 2.5%.