饲料维生素A对美国红鱼生长和免疫的影响(英文)

Effects of Dietary Vitamin A Levels on Growth and Immune Response of Red Drum(Sciaenops Ocellatus L.)

本试验旨在研究饲料维生素A对美国红鱼生长(增重率、特定生长率、存活率和饲料效率)和免疫反应相关指标(血清中溶菌酶活性、超氧化物歧化酶活性和总补体活性)的影响。采用单因子试验设计,将300尾平均体重为(151.46±8.18)g的美国红鱼随机分为5个处理,每个处理设3个重复,每个重复20尾,分别饲喂5种不同VA水平(30、4166、8533、18532、33263IU/kg)的等氮等能饲料,进行为期8周的生长试验。结果表明:饲料中VA水平为30IU/kg时其增重率、饲料效率、特定生长率、成活率均显著低于4166、8533、18532IU/kg组(P<0.05),VA水平为33263IU/kg时各指标有所降低,其中饲料效率和特定生长率显著低于4166、8533、18532IU/kg组(P<0.05);VA水平为30IU/kg时血清溶菌酶活性、SOD活性和总补体活性显著低于其他组(P<0.05),VA水平在18532IU/kg时血清溶菌酶活性达到最高值,其次为33263、8533、4166IU/kg组;VA水平在8533IU/kg时血清SOD和总补体活性达到最高值,并显著高于4166、18532、33263IU/kg组(P<0.05)。综上所述,饲料中适宜VA水平能显著促进美国红鱼生长、提高相关免疫力,且饲料VA水平为8533IU/kg时对美国红鱼生长和免疫相关指标影响较显著。

A single factor design was conducted to study the effects of dietary vitamin A on growth （weight gain rate, specific growth rate, survival rate and feed efficiency ratio） and immune response （lysozyme activity, superoxide dismutase （SOD） activity and total complement activity） of red drum （ Sciaenops Ocellatus L. ）. Three hundred fish with body weights of （151.46±8.18） g were randomly allocated to 5 treatments with 3 replicates each and 20 fish in each replicate. Six treatments were fed with 5 iso-nitrogenous and iso-energetic diets containing 5 levels of vitamin A （30, 4 166, 8 533, 18 532 and 33 263 IU/kg diet, respectively）, and the experiment lasted for 8 weeks. The results showed that, 30 IU/kg treatment had the lowest weight gain rate, specific growth rate, survival rate and feed efficiency ratio, and lower than those in 4 166, 8 533,18 532 IU/kg treatments significantly （P〈0.05）. Specific growth rate and feed efficiency ratio in 33 263 IU/kg treatment were lower than those in 4 166, 8 533, 18 532 IU/kg treatments significantly （P〈0.05）. The lysozyme activity, SOD activity and total complement activity in 30 IU/kg treatment were significantly lower than those in other treatments （P〈0.05）. The maximal level of lysozyme activity was in 18 532 IU/kg treatment, followed by 8 533, 4 166, 33 263 IU/kg treatments. The maximal level of SOD activity and total complement activity was in 8 533 IU/kg treatment, and higher than those in 4 166, 18 532, 33 263 IU/kg treatments significantly （P〈0.05）. In conclusion, the growth performance and immune response of red drum could be improved significantly by the proper dietary vitamin A level, and optimum level of vitamin A to improve growth performance and immune response of red drum was 8 533 IU/kg.