饲料颗粒长度及投喂方法对管角螺生长和水中氨氮含量的影响

Effect of feed pellet length and feeding method on the growth of Hemifusus tuba and ammonia-N concentration in the water

以蛋白质含量40%,脂肪含量9%的配合饲料为试验饲料,采用单因子试验研究了饲料颗粒长度(5、10、15、20mm)、日投喂量(3%、6%、9%、12%)和日投喂频率(每天1次、2次、3次、4次)对管角螺(Hemifusus tuba)幼螺(壳高2.37±0.03 cm)的特定生长率、饲料效率、存活率和水中氨氮含量的影响。结果表明,饲料颗粒长度、日投喂量和日投喂频率对幼螺的存活率均无显著影响(P>0.05),各组存活率均在95%以上,但对幼螺特定生长率、饲料效率和水中氨氮含量均有显著影响(P<0.05),其中饲料颗粒长度10 mm饲料组效果最佳,颗粒长度5 mm组效果最差;日投喂量为6%组效果最佳,日投喂量为12%组效果最差;日投喂频率为2次·d-1组效果最好。结果表明,管角螺幼螺养殖以饲料颗粒长度为10 mm、日投喂频率为每天2次、日投喂量为体重的6%为宜。

Single-factor test design was conducted to study the effect of feed pellet length, feeding rate and feeding frequency on specific growth rate, feed efficiency, survival rate and ammonia-N concentration for juvenile Hemifusus tuba. The feed pellet length was 5 ram, I0 ram, 15 mm and 20 ram; the feeding rate was 3%, 6%, 9% and 12%; feeding frequency was 1 time per day, 2 times per day, 3 times per day, 4 times per day, respectively. The results showed that the survival rate was not significantly influenced by the feed pellet length, feeding rate or feeding frequency; the survival rate was above 95% among all treatments. However, specific growth rate, feed efficiency and ammonia-N in water were significantly affected by the treatments. The animals fed with the 10 mm pellet length diet had higher value than those fed with the other treatment, and the poorest value was observed in those fed with the 5 mm pellet length diet. As for the feeding rate, the best value was observed in the group in which the feeding rate was 6%, and the poorest value was observed in the group in which the feeding rate was 12%. The optimum feeding frequency was observed in 2 times per day. These results demonstrated that the optimal feed pellet length, feeding rate and feeding frequency were 10 ram, 2 times per day and 6%, respectively.