中成鱼阶段卵形鲳鲹对饲料蛋白质和脂肪的适宜需求量

Dietary protein and lipid optimum requirements for on-growing golden Pompano (Trachinotus ovatus)

通过添加不同浓度鱼粉,制成6组等脂等能的蛋白质梯度实验饲料(P1~P6),研究中成鱼阶段(初始体质量范围定义为>100 g/只的个体)卵形鲳鲹对饲料中蛋白质的最适需求量。研究发现,随着饲料中蛋白质含量的升高(P1~P6),实验鱼的生长性能如增重率、蛋白质效率以及全鱼粗蛋白含量均呈现先显著升高(P<0.05)而后逐渐平稳的趋势(P>0.05),而饲料系数和摄食率呈现先显著降低(P<0.05)而后轻微升高的趋势(P>0.05)。折线回归模型拟合生长性能,计算中成鱼阶段卵形鲳鲹对饲料中蛋白质的最适需求量(质量分数)为49.75%。在获得蛋白质需求的基础上,通过添加不同水平的豆油,制成6组等氮的脂肪梯度实验饲料(L1~L6),研究中成鱼阶段卵形鲳鲹对饲料中脂肪的最适需求量。随着饲料中脂肪含量提高(L1~L6),卵形鲳鲹的增重率等生长性能呈现先显著升高后稳定的趋势(P<0.05),而饲料系数和摄食率则呈现先显著降低后稳定的趋势(P<0.05)。折线回归模型拟合生长性能,计算中成鱼阶段卵形鲳鲹对饲料中脂肪的最适需求量(质量分数)为12.20%~12.27%。

Six isolipidic practical diets were formulated to contain different levels of fish meal(six graded protein levels were named P1-P6 respectively).Fish was fed by hand twice daily until apparent satiation.The growth performance of fish including weight gain rate as well as protein efficiency rate significantly increased(P<0.05)with increasing dietary protein levels(P1-P6)and then kept steady(P>0.05).Growth performance of fish fed P4,P5 and P6 was significantly higher than that of fish fed P1,P2 and P3(P<0.05).While feed conversion ratio and feed intake decreased significantly(P<0.05)with increasing levels of dietary protein up to 49.75%and remained nearly the same thereafter.Feed conversion ratio and feed intake in P4 and P5 were significantly lower than those of fish fed P1,P2 and P3(P<0.05).Regression analysis showed that the recommended optimum dietary protein level for on-growing golden pompano was 49.75%(mass fraction).On the basis of dietary protein requirement,another 12-week feeding trial was conducted to evaluate dietary lipid requirement for on-growing golden pompano.Six isocaloric practical diets were formulated to contain different levels of soybean oil(six graded lipid levels were named L1-L6 respectively).With the increase of dietary lipid levels(L1-L6),growth performance of fish including weight gain rate and protein efficiency rate first significantly increased and then kept steady(P>0.05).Growth performance of fish fed L3,L4,L5 and L6 was significantly higher than that of fish fed L1 and L2(P<0.05).Feed conversion ratio and feed intake decreased with increasing levels of dietary lipid up to 12.20%and remained nearly the same thereafter.Feed conversion ratio and feed intake in L3,L4,L5 and L6 were significantly lower than those of fish fed L1 and L2(P<0.05).Regression analysis showed that the recommended optimum dietary lipid level for golden pompano(121-580 g)was 12.20%-12.27%(mass fraction).