摘要
以n 3HUFA含量为 0 16 %、 1 2 7%、 2 36 %和 3 4 7%的 4种人工配合饲料 (D1～D4 )及天然饲料(冰鲜杂鱼 ,D5 )饲养花尾胡椒鲷 (Plectorhynchuscinctus)雌亲鱼一周年 ,通过比较各饲料组亲鱼的产卵量、卵和仔鱼质量以及各月份的血浆性类固醇激素水平 ,研究n 3HUFA对生殖性能及性类固醇激素水平季节性变化的影响。平均每kg雌鱼的产卵量、卵受精率、仔鱼存活率、开口仔鱼体长等 ,D2和D3组与D5组相近 ,但D1和D4组显著低于D5组 ;饲料中n 3HUFA含量对血浆 17β -雌二醇 (E2 )和睾酮 (T)水平的季节性变化规律无明显影响 ,但亲鱼性腺发育与成熟时期的E2 和T水平 ,D1和D4组较D5组显著降低。n 3HUFA含量对亲鱼离体卵泡E2 和T的分泌也有一定影响 :D4组卵泡E2 的基础分泌很少 ;绒毛膜促性腺激素 (HCG ,10 0IU/mL)可刺激D2—D5组卵泡分泌E2 和T ,但D1组卵泡对HCG无反应。结果提示 ,花尾胡椒鲷亲鱼饲料中n 3HUFA的适宜含量为 1 2 7%～ 2 36 % ,不足或过高对亲鱼的生殖性能均有不利影响 ;通过影响性类固醇激素的产生可能是饲料中n
In order to study the effects of n-3 highly unsaturated fatty acids (n-3 HUFA) content in broodstock diets on the reproductive performance and seasonal changes of plasma sex steroids levels,five groups of Plectorhynchus cinctus female broodstocks were respectively fed a natural diet composed of trash fish (D5) and four artificial formulated diets containing 0.16% (D1),1.27% (D2),2.36% (D3) and 3.47% (D4) of n-3 HUFA,during the whole reproductive cycle.Their fecundity,egg and larval quality were evaluated,and the levels of plasma sex steroids were monthly monitored.It was found that the eggs production/kg of female,fertilization rate of eggs,larval survival and length at mouth-opening stage of both D2 and D3 group were equivalent to those of D5 group;however,those of D1 and D4 group were significantly lower than D5 group.Dietary n-3 HUFA content showed no obvious influence on the seasonal change pattern of plasma 17β-estradiol (E 2) and testosterone (T).However,the plasma E 2 and T levels in gonad developmental and mature seasons of D1 and D4 group were significantly lower than those of D5 group.Dietary n-3 HUFA content also displayed some influence on E 2 and T production by in vitro ovarian follicles.Little basic E 2 production was observed by ovarian follicles of D4 group.Human chorionic gonadotropin (HCG,100 IU/mL) stimulated E 2 and T production by ovarian follicles of D2-D5 group;however,ovarian follicles of D1 group had no response to HCG.The results suggest that the optimum n-3 HUFA requirements in broodstock diet of P.cinctus range between 1.27% and 2.36%,deficient or high dietary n-3 HUFA content may have negative effect on reproductive performance of broodstocks;n-3 HUFA may affect the reproductive performance by influencing the production of sex steroids.
基金
国家自然科学基金资助项目 ( 3 0 0 70 5 99)
