投喂策略对厚颌鲂幼鱼的生长、肠道消化酶活性和形态学的影响

Effects of Feeding Strategies on Growth, Intestine Digestive Enzymes Activities and Intestine Morphology of Megalobrama pellegrini

为了研究投喂策略(投喂率和投喂频率)对厚颌鲂幼鱼生长、消化酶活性和肠道发育的影响,本实验在流水养殖系统中开展了42天的厚颌鲂幼鱼养殖实验,设计了3个投喂率(5%,6.5%,8%体重/d)和2个投喂频率(2次/d、3次/d),每种投喂策略设定3个平行,饲喂商品饲料(33%粗蛋白,4%粗脂肪).结果表明,在投喂6.5%体重/d和3次/d的实验组,其鱼体增重率最高,且显著高于2次/d和3次/d投喂频率下投喂率为5%体重/d和8%体重/d的投喂组增重率,表明厚颌鲂幼鱼的生长显著受到投喂率的影响,但投喂频率对生长的影响并不显著;投喂率为8%体重/d和投喂频率为3次/d时,饲料系数显著高于其他各实验组的饲料系数;在实验过程中,投喂策略为8%体重/d和2次/d的实验组,其死亡率较高,而其他组的实验鱼其存活率均较高(90%以上),且各组间无显著差异;与其他处理组相比,在8%体重/d和3次/d的实验组,其鱼体粗蛋白、粗脂肪和肠消化酶活性显著降低;同时,该组与其他处理组相比,其肠道绒毛有融合和脱落的现象.综上所述,在流水养殖模式下,投喂率为6.5%体重/d和投喂频率为2次/d的投喂策略对于厚颌鲂幼鱼的生长最佳.

In our report, in order to analyze the effects of feeding rate and feeding frequency on growth performance, digestive enzymes activities and intestine development of Megalobrama pellegrini in replicated flow-through system, a 42-day experiment was performed, in which three feeding rate(5%, 6.5% and 8% body weight/day, BW/d) and two feeding frequency(2 and 3 meals/day, m/d), with a commercial diet(33% crude protein, 4% total lipid), were designed. The results showed that the highest weight gain was found in fish with 6.5% BW/day and 3 m/d, which was significant higher compared with that of other feeding rate groups(5% BW/d and 8% BW/d) at both feeding frequency(2 and 3 m/d), and which suggested that fish growth performance was significantly affected by the feeding rate but not by the feeding frequency. The significant higher feed conversion ratio(FCR) was recorded at 8% BW/d with 3 m/d compared with other treatments. When fish fed diet was at 8% BW/d with 2 m/d, the mortality was higher that of other groups. When fish fed diet was at 8% BW/d with 3 m/d, the whole-body crude protein, lipid and intestine digestive enzymes were significant lower than that of other groups, with intestine villi fusion and exfoliation observed. In conclusion, M. pellegrini fed diet with feeding rate of 6.5% BW/d and feeding frequency of 2 m/d could be the optimum feeding strategies raised in flow-through system.