饲料中不同水平维生素A对加州鲈生长和血清生化指标的影响

Effects of different dietary levels of vitamin A on growth performance and serum biochemical parameters of Micropterus salmoides

通过对平均初重为(38.31±0.26)g的加州鲈(Micropterus salmoides)投喂5组不同维生素A水平的饲料[维生素A含量分别为3.59(对照组)、16.26、33.19、63.65 mg/kg和116.49 mg/kg],每组3个重复,每个重复50尾鱼,进行8周的饲养试验,研究饲料中不同水平维生素A对加州鲈幼鱼生长和血清生化指标的影响。结果表明,与对照组相比,饲料中添加63.65 mg/kg维生素A可显著提高加州鲈的增重率和特定生长率(P<0.05),而对蛋白质效率、饲料系数、成活率和体成分影响不显著(P>0.05)。但超过一定量的维生素A(116.49 mg/kg),反而不利于加州鲈的生长和骨骼发育。当饲料中维生素A添加水平为116.49 mg/kg时,显著降低了血清总胆固醇和肝脏脂肪含量(P<0.05),当饲料中维生素A添加水平为63.65 mg/kg时,显著提高了血清谷草转氨酶的活性(P<0.05),而对血清碱性磷酸酶和谷丙转氨酶没有显著性影响(P>0.05)。此外,肝脏维生素A含量随着饲料维生素A水平的增加而呈线性增加。由此可见,在需要量基础上适当提高维生素A水平可促进加州鲈的生长,建议加州鲈饲料维生素A的添加量不能高于63.65 mg/kg。

To investigate the effects of dietary vitamin A on growth performance and serum biochemical parameters of Micropterus salmoides, five diets supplemented with graded levels of vitamin A （3.59（control）, 16.26, 33.19, 63.65 and 116.49 mg/kg dry weight, respectively） were fed to triplicate treatments of 50 juveniles each with the initial weight of （38.31±0.26） g for 8 weeks. The results showed that the weight gain （WG） and special growth rate （SGR） of fish fed the diet with 63.65 mg/kg vitamin A were significantly higher than those of control group （P〈0.05）. No significant differences were observed in protein efficiency ratio （PER）, feed conversion ratio （FCR）, survival rate （SR） and proximate composition of whole body fish among all the treatments （P〉0.05）. While high concentration of dietary vitamin A （116.49 mg/kg） caused slight depression in growth and bone development of juvenile fish. Serum cho- lesterol and liver lipid contents were significantly decreased with increasing dietary vitamin A level up to 63.65-116.49 mg/kg, but the reverse trend was obtained for serum aspartate aminotransferase （GOT） activity （P〈0.05）. No significant differences were observed on alkaline phosphatase （ALP） activity and glutamic pyruvic transaminase （GTP） activity in serum （P〉0.05）. The liver vitamin A contents showed a strong positive linear relationship with dietary vitamin A levels （P〈0.05）. The results of the present study indicated that certain high levels of dietary vitamin A could improve growth for juvenile Micropterus salmoides, and the level of dietary vitamin A should not exceed 63.65 mg/kg.