饲料糖水平与投喂频率对鲤生长性能、肠道消化能力及肝功能的影响

Effects of different dietary carbohydrate levels and feeding frequency on growth performance,intestinal digestive ability and hepatic function of common carp

为研究饲料糖水平(5%、10%、20%)和投喂频率(2、4次/d)及其交互作用对鲤生长、肠道消化能力和肝功能的影响,本试验拟选用平均体重为(55.37±3.55)g的鲤为试验对象,采用3×2双因子试验设计,在池塘浮式网箱(1m×1m×1.5m)中进行养殖试验。养殖周期为8周。结果表明:投喂频率对鲤的增重率、特定增长率、蛋白质效率及肥满度影响显著(P<0.05);投喂频率、饲料糖水平及其交互作用均对肝体比影响显著(P<0.05)。在5%和10%糖水平组中,4次/d投喂组的增重率较2次/d投喂组分别提高了33.4%和44.9%,4次/d投喂组的蛋白质效率较2次/d投喂组分别提高了33.6%和45.1%(P<0.05)。在10%糖水平组中,4次/d投喂组的特定生长率较2次/d投喂组提高了30.7%(P<0.05),饵料系数较2次/d投喂组降低了31.3%(P<0.05)。投喂频率对前肠蛋白酶、中肠淀粉酶及中肠脂肪酶活性影响显著(P<0.05),饲料糖水平对中肠蛋白酶、中肠淀粉酶活性影响显著(P<0.05)。在10%糖水平组中,4次/d投喂组的中肠蛋白酶活性显著高于投喂频率为2次/d投喂组(P<0.05)。饲料糖水平和投喂频率对鲤血清和肝脏中的谷丙转氨酶及谷草转氨酶影响均不显著(P>0.05)。在同一糖水平下,血清谷丙转氨酶和谷草转氨酶均随投喂频率提高而降低(P<0.05)。综合分析,从降低饲料成本,提升鱼体生长性能、消化能力及肝功能的角度出发,在固定日投喂率的情况下,投喂频率为4次,饲料糖水平为10%为最佳选择。

A 8-week 3 ×2 two-factorial experiment was conducted to investigate the effects of dietary carbohydrate levels (5%,10%,20%) and feeding frequencies (fourth daily and twice daily) on the growth,digestion and liver function of common carp with initial average weight of(55.37±3.55)g,cultured in floating net cages.Three replicates with 180 com-mon carp were randomly allotted to one treatment with combination of dietary carbohydrate level and feeding frequency in a complete randomized design.The results showed that the weight gain ratio(WGR),special growth ratio(SGR),protein ef-ficient ratio (PER),hepatosomatic (HSI) and condition factor (CF) were significantly affected by feeding frequency (P <0.05).Compared with fish fed twice daily at 5% and 10% dietary carbohydrate levels,WGR of fish fed fourth daily at 5%and 10% dietary carbohydrate levels was increased by 33.4% and 44.9%,respectively,and PER was increased by 33.6%and 45.1%,respectively(P<0.05).At 10%dietary carbohydrate level group,SGR of fish fed twice daily was increased by 30.7%and(P<0.05),and feed conversion rate (FCR) was decreased by 31.3%(P<0.05).Feeding frequency had signif-icant effect on activities of protease of forecgut,amylase of midgut and lipase of midgut,and dietary carbohydrate levels had significant effect on activities of protease and amylase of midgut(P < 0.05).At 10% dietary carbohydrate level group, activities of protease of fish fed fourth daily was significantly higher than fish fed twice daily.Feeding frequency and carbo-hydrate leve had no significant effect on liver and serum alanine transaminase (ALT) and aspartate transaminase (AST) level (P > 0.05).Regardless of dietary carbohydrate level,higher feeding frequency could lead to lower serum ALT and AST level.Combined the results of this study and the practice of common carp production,the common carp should be fed at 4 meal/d,and the carbohydrate content of the dietary can be appropriately increased to 10%.