吡啶甲酸铬对吉富罗非鱼生长、饲料利用和非特异性免疫功能的影响

本试验研究饲料不同水平吡啶甲酸铬对其生长、饲料利用,体成分、血液生化指标和非特异性免疫功能的影响。600尾吉富罗非鱼分为5个处理组,每个处理各设4个重复,每重复30尾鱼。每个处理铬添加量分别为0、0.4、0.8、1.2 mg/kg和10.0 mg/kg,在0.38 m3玻璃纤维钢桶中用开放式流水养殖,饲养8周。结果表明,饲料中添加吡啶甲酸铬对吉富罗非鱼的增重率、特异生长率、饲料系数、蛋白效率及蛋白质沉积率均有显著影响(P<0.05)。当铬添加量为0～0.8 mg/kg时,随着添加量增加,可显著提高吉富罗非鱼增重率、特定生长率、蛋白质效率和蛋白质沉积率(P<0.05),显著降低饲料系数(P<0.05),但对成活率和肝体比无显著影响(P>0.05);当饲料中添加为1.2 mg/kg～10.0 mg/kg时并未能进一步提高罗非鱼的生长和饲料利用。同时,铬添加水平为0～0.8 mg/kg,随着添加水平增加,显著提高吉富罗非鱼全鱼的蛋白质和磷含量(P<0.05),显著降低全鱼水分、脂肪和灰分含量(P<0.05),并显著提高吉富罗非鱼血清总蛋白含量以及肝胰脏AKP、ACP和LZM的活性(P<0.05),显著降低血清葡萄糖含量(P<0.05),但对血清胆固醇和甘油三酯含量及肝胰脏T-SOD活性无显著影响(P>0.05)。当饲料中添加铬1.2 mg/kg和10.0 mg/kg,除了显著降低肝胰脏AKP活性外(P<0.05),对血清生化指标和肝胰脏非特异性免疫酶活性无显著影响(P>0.05)。综合生长、饲料利用、体组成成分、血液生化指标和肝胰脏非特异性免疫酶活性的影响结果表明,对于0.91～4.93 g吉富罗非鱼,饲料中以吡啶甲酸铬的形式添加0.8～1.2 mg/kg铬为宜。

Effects of chromium picolinate on growth performance,feed utilization and non-specific immunity in juvenile hybrid tilapia (Oreochromis niloticus)

The trial was conducted to determine the effects of chromium picolinate with dietary different supplementation levels(Chromium Cr was 0,0.4,0.8,1.2 mg/kg and 10.0 mg/kg,respectively) on growth performance,feed utilization,body composition,blood biochemical index and non-specific immunity of juvenile hybrid tilapia(Oreochromis niloticus) for 8 weeks.Five kinds of iso-nitrogenous and iso-energies diets were formulated as experimental diets.A total of 600 fish were randomly distributed into twenty 0.38m3 fiberglass tanks with 30 fish per tank and 4 tanks per diet.The results showed that in 8-weeks feeding trial,the diet with 0 ～ 0.8mg/kg Cr supplementation could significantly increase the weight grain(WG),specific growth rate(SGR),protein efficiency ratio(PER) and productive protein value(PPV) of juvenile hybrid tilapia(P < 0.05),and significantly decrease feed convention ratio(FCR)(P < 0.05),while the survival rate and hepatopancreas somatic index(HSI) were not significantly affected(P > 0.05).The whole boby crude protein and phosphorous(P) content were significantly increase by the diets with 0 ～ 0.8mg/kg Cr supplementation levels(P < 0.05),whereas the effects on moisture,crude lipid and crude ash content in whole body.As the same time,the diet with 1.2mg/kg or 10.0 mg/kg Cr supplementation could not significantly increase the growth and feed utilization of the fish than those of the diet with 0.8mg/kg Cr supplementation levels(P > 0.05).Activities of hepatopancreas total superoxide dismutase(T-SOD) and the content of cholesterol and triglyceride in serum,was not significantly affected by the dietary Cr supplementation levels(P > 0.05).Except of the activity of hepatopancreas acid phosphatase(ACP),activities of alkaline phosphatase(AKP) and lysozyme(LZM) in hepatopancreas and the contents of total protein and glucose in serum decreased significantly(P < 0.05),when the dietary without Cr supplementation or excess of 0.8mg/kg supplementation.Based on weight gain rate,feed utilization,body conposition,blood biochemical index and the non-specfic immunity,the optimal dietary supplementation levels of Cr(the form of chromium picolinate) for the tilapia diet formulation was 0.8 mg/kg.