饲料蛋白质水平对日本无针乌贼生长性能和肌肉营养成分的影响

为研究饲料中不同蛋白质水平对日本无针乌贼生长性能及肌肉营养成分的影响, 试验配制了蛋白质水平为35%、40%、45%、50%、55%共5组试验饲料, 对初始体重为(37.86±5.63)g的(P>0.05). 当饲料蛋白质水平为50%时, 肌肉中粗蛋白(82.09%)、氨基酸总量(80.45%)达最大值, 而肌肉粗脂肪在饲料蛋白质55%组达到最大(6.33%), 均显著高于其他4组(P<0.05). 对肌肉氨基酸和脂肪酸的分析结果表明: 肌肉中必需氨基酸量(28.29%)和鲜味氨基酸量(33.03%)在45%和50%两组间无显著性差异(P>0.05),但显著高于其他3组(P<0.05); 总不饱和脂肪酸(EPA+DHA)呈先降后升的趋势, 在45%组和50%组显著低于其他组(P<0.05). 根据SGR折线模型拟合回归方程分析得出, 日本无针乌贼对饲料蛋白质的需求量为44.73%

Effects of Dietary Protein Levels on Growth Performance and Main Composition of Muscle inSepiella japonica

This research is conducted to reveal the effects of the dietary protein on the growth performance and main composition of muscle of cuttlefish Sepiella japonica. Five practical diets are formulated with various protein levels which is ranked by 35%, 40%, 45%, 50% and 55%, respectively. Sepiella japonica with initial weight of (37.86±5.63)g are fed with 5 experimental diets and the feeding process last for 30 days. The results show that: the final body weight, weight gain rate, specific growth rate, survival rate and protein efficiency ratio first increase significantly (P<0.05) with increasing dietary protein level from 35% to 45%, and then decrease. However, the mantle length relative growth rate, hepatosomatic index, feed conversion ratio and condition factor are insusceptible to the change of protein levels. The crude protein (82.09%) and total amino acids (80.45%) of the muscle reach the highest value at the dietary protein level of 50%. Meanwhile, the value of crude lipid (6.33%) is found to be the highest at the dietary protein level of 55%, which is significantly higher than other four groups (P<0.05). Muscle amino acids and fatty acids analyses indicate that the essential amino acids (28.29%) and flavor amino acids (33.03%) shows no significant difference between groups of 45% and 50% (P>0.05), but significantly higher than other three groups (P<0.05). Unsaturated fatty acids including EPA and DHA decline first and then rise, which are significantly lower than that in the group of 45% and 50%. Based on the analyses of broken-line regression of SGR, the optimal dietary protein level for cuttlefish Sepiella japonica is identified for 44.73%