投 喂 频 率 对 大 口 黑 鲈 幼 鱼 生 长 及 消 化 的 影 响.

In order to explore the effects of feeding frequency on the growth and digestibility of Microp⁃ terus salmoides with fixed feeding rate that under satiation, five feeding frequencies (2 times/d, 3 times/d, 4 times/d, 5 times/d, 6 times/d) were evaluated in triplicate recirculating aquaculture systems for 56 days. The results show that: the specific growth rate of 3、4 and 5 times/d groups were significantly higher than that of 6 times/d group (P<0.05); the weight gain rate of 3 and 5 times/d groups were significantly higher than that of 6 times/d group (P<0.05); the feeding rate of the 5 times/d group was the highest; the protein efficiency of 2 and 3 times/d groups were significantly higher than that of 4 and 6 times/d groups (P< 0.05); the fatness of the 6 times/d group was significantly higher than that of the 3 times/d group (P< 0.05); the ratio of viscera to body in the 2 times/d group was significantly higher than that in the 3, 4 and 6 times/d groups (P<0.05). In stomach, the activity of AMS and LPS appeared in the 2 times/d group and 5 times/d group respectively (P<0.05). In py‐ loric caecum, the values of AMS activity and LPS activity appeared in the 6 times/d group and 5 times/d group respectively (P<0.05). In midgut, the activity of AMS and LPS appeared in the 5 times/d group and 3 times/d group respectively (P<0.05). In hepatopancreas, the activity of AMS and LPS appeared in the 4 times/d group and 2 times/d group respectively (P<0.05). The villus height of the foregut in the 3 times/d group was the largest (P<0.05), the villus width was significantly higher than that in the 4, 5 and 6 times/d groups (P<0.05), and the muscular layer thickness was significantly higher than that in the 2, 4 and 5 times/d groups (P<0.05); in midgut, the villus height and muscular layer thick‐ ness of the 2 times/d group were the largest (P<0.05), and the villus width of the 4 times/d group was sig‐ nificantly higher than that of the 3, 5 and 6 times/d groups (P<0.05); the maximum values of villus height, villus width and muscular thickness of the hindgut appeared in the 2 times/d group, 3 times/d and 6 times/d groups respectively (P<0.05). In the tissue sections of hepatopancreas, the cell contour and nuclear clarity of the 2 and 3 times/d groups were better than those of the high-frequency feeding groups. From the perspective of growth performance, digestion ability and tissue health of Micropterus salmoides, the appropriate feeding frequency for young Micropterus salmoides is 3 times/d in the circulat‐ ing water system. [ABSTRACT FROM AUTHOR]