饲料蛋白水平对匙吻鲟幼鱼肌肉营养成分及消化酶活力的影响

配制蛋白水平34.16%、36.53%、39.10%和41.08%的4种等能半精制饲料,在水温28～32℃条件下,饲喂体质量(19.91±3.73)g的匙吻鲟45d,研究饲料蛋白水平对匙吻鲟肌肉营养成分和消化酶(酸性蛋白酶、碱性蛋白酶、α-淀粉酶和脂肪酶)活性的影响。结果显示,41.08%组体质量显著高于36.53%组,其余各组体质量差异不显著;肌肉粗蛋白含量随着饲料蛋白水平的增加而增加,各组肌肉水分、粗脂肪和粗灰分含量差异不显著;酸性蛋白酶和肝胰脏碱性蛋白酶活力随饲料蛋白水平的增加而增加,而肠道碱性蛋白酶活力随饲料蛋白水平的增加而降低;消化道α-淀粉酶活力随饲料蛋白水平的增加而降低,而肝胰脏α-淀粉酶活力表现出相反的趋势;饲料蛋白水平对消化道和肝胰脏脂肪酶活力影响不显著,各组脂肪酶活力差异不显著。试验结果表明,饲料蛋白水平对匙吻鲟肌肉粗蛋白含量、酸性蛋白酶、碱性蛋白酶和α-淀粉酶都会产生显著影响;饲料蛋白水平为39.10%比较适宜。

Effects of Dietary Protein Levels on Muscle Composition and Digestive Enzyme Activities in Juvenile Paddlefish Polyodon spathula

Four isoenergic semi-purified test diets containing graded levels of protein(34.16%,36.53%,39.10% and 41.08%) were formulated and fed paddlefish Polyodon spathula juveniles-initial body weight of(19.91±3.73) g-] for 45 days to study effects of dietary protein levels on the muscle composition and digestive enzyme activities at water temperature of 28~32 ℃.The results showed that there was significantly higher final body weight in the fish fed the dietary containing 41.08% of protein than that in the fish fed the diets containing 36.53%,without significant differences among other groups.There was no significant effect of the diet ary protein levels on the muscle moisture,and crude lipid and ash levels in the juveniles,though the muscle crude protein was increased with the increase in the dietary protein.Both acid protease activity and alkaline protease activity in the hepatopancreas were found significantly increase with the increase in the dietary protein,while alkaline protease activity in the intestine was decreased with increase in the dietary protein levels.The activity of α-amylases in the digestive tract was decreased with increase in the dietary protein levels,while α-amylases activity in the hepatopancreas showed an opposite trend.There was no significant difference in lipase activity in all tested tissues within the dietary protein treatments.It is suggested that the optimal dietary protein for paddlefish juveniles be 39.10%.