中成鱼阶段卵形鲳鲹对饲料蛋白质和脂肪的适宜需求量

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(P0.05)而后逐渐平稳的趋势(P0.05),而饲料系数和摄食率呈现先显著降低(P0.05)而后轻微升高的趋势(P0.05)。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(P0.05),而饲料系数和摄食率则呈现先显著降低后稳定的趋势(P0.05)。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%。

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

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).