军曹鱼幼鱼日粮锌最适添加量的研究

试验选用234尾军曹鱼随机分为6个处理,每处理设3个重复,每重复13尾鱼,采用单因素浓度梯度法研究军曹鱼幼鱼商品饲料中锌的最适添加量。在基础日粮(锌含量为75.47mg/kg)中分别添加锌0、30、70、110、150和190mg/kg,制成6种试验日粮,分别投喂军曹鱼幼鱼6周。试验结果表明,基础日粮组鱼成活率、饲料系数、特定生长率、血清碱性磷酸酶(AKP)活性、肌肉和血清锌含量与添加锌组无显著差异(P>0.05)。添加锌组骨骼和肝脏锌含量与基础日粮组差异显著(P<0.05),表现为随锌添加的增加而上升的趋势。以成活率和特定生长率为评价指标,军曹鱼商品日粮中的锌含量可以满足其正常生长需求,不需要额外添加锌。

Study on the potimum zinc level in diets of juvenile cobia

Two hundred and thirty four juvenile cobia(Rachycentron Canadum)were divided into 6 treatments.There were 3 replicates in every treatment with 13 cobia per replicate.6-week feeding trial by commercial diet with supplements of 0,30,70,110,150 and 190 mg/kg Zn was conducted to determine the optimum zinc supplementation level of juvenile cobia(Rachycentron Canadum).The results showed that there were no significant differences in survival rate,weight gain rate,feed conversion rate,serum alkaline phosphatase activity,muscle and serum zinc concentrations of all treatment.There was a significant difference among the zinc concentrations,which were on the rise with the increase in the zinc supplements,in bone and liver for fish fed the diet with zinc supplementation levels(P < 0.05).The bone and live zinc concentrations were responded in broken-lines models with the increase of dietary zinc levels.By considering survival rate and specific growth rate,it was demonstrated that there were not necessary adding zinc to the commercial diets and the zinc content in the feedstuff of the diets was enough for the juvenile cobia.