过量维生素A对育成期雄性水貂生长性能及血清生化指标的影响

The Effects of Excessive Vitamin A Supplementation on Growth Performance and Serum Biochemical Indices in Growing Male Minks

旨在讨论饲粮中过量维生素A对育成期水貂生长性能、营养物质代谢及血清生化指标的影响。本研究采用单因素随机试验设计,选择雄性水貂90只,随机分成6组,每组15个重复,维生素A添加水平分别为0(对照组)、5 000(Ⅰ组)、20 000(Ⅱ组)、80 000(Ⅲ组)、320 000(Ⅳ组)及1 280 000IU·kg-1(Ⅴ组)(干物质基础)。预饲期7d,正式试验期60d。正式期开始第30天每组随机选取8只水貂进行为期3d的消化代谢试验,采用全收粪法收集粪便及尿样,测定各样品中的干物质(DM)、蛋白质(CP)及脂肪(EE)的含量,计算水貂的营养物质消化率。试验结束时,采集血清样本进行血糖(GLU)、三酰甘油(TG)、胆固醇(CHO)、高密度脂蛋白胆固醇(HDL)、低密度脂蛋白胆固醇(LDL)、碱性磷酸酶(ALP)、天门冬酸氨基移酶(AST)、丙氨酸氨基转移酶(ALT)及乳糖脱氢酶(LDH)的测定。结果表明:1)添加维生素A对水貂的末重、平均日增重均有显著影响,其中Ⅱ组与Ⅴ组间差异显著(P<0.05)。2)对照组营养物质消化率较其他组显著降低(P<0.05),其中Ⅱ组的营养物质消化率最高。3)维生素A对水貂血清中GLU、CHO含量的影响均不显著(P>0.05),Ⅱ组血清中TG含量最低,与Ⅴ组差异显著(P<0.05)。对照组、Ⅰ组、Ⅱ组、Ⅲ组血清中的HDL含量同Ⅳ组与Ⅴ组差异显著(P<0.05)。Ⅰ组的LDL含量最低,显著低于Ⅳ组与Ⅴ组(P<0.05),其余组差异不显著(P>0.05)。4)维生素A对水貂血清中的ALP、AST、ALT及LDH水平均有显著影响(P<0.05),其中对照、Ⅲ、Ⅳ组同Ⅴ组血清中的ALP含量差异显著(P<0.05)。Ⅱ组血清中AST的含量最低,显著低于对照组、Ⅳ组及Ⅴ组(P<0.05)。Ⅱ组血清中的ALT含量最低,显著低于其余各组(P<0.05),Ⅴ组显著高于对照组、Ⅰ、Ⅱ组(P<0.05)。Ⅴ组LDH的含量最低,且显著低于Ⅰ、Ⅱ、Ⅲ组(P<0.05),对照组同Ⅳ组差异不显著(P>0.05)。在本试验条件下,在水貂饲粮中添加5 000～80 000IU·kg-1维生素A均可以优化水貂的生长潜力。然而过量添加维生素A会造成水貂生长缓慢,脂类代谢能力下降等不良影响,过量添加维生素A对水貂生长造成的不良影响的机制仍需进一步研究。

The aim of this study was to investigate the effects of excessive vitamin A（VA） supple mentation on growth performance, nutrient digestibility and serum biochemical indexes of growing male edO0（D,20 000（Ⅱ）, 80 000（Ⅲ）, 320 000（Ⅳ） and 1 280 000 IU·kg I（Ⅴ） VA （based on dry matter）the pretest period lasted for 7 days and theof the trail, 8 minks from each groupselected randomly for the digestio On the 30th day of the trail, 8 minks from each group were selected randomly for the digestion andmetabolism test for 3 days, the feces and urine samples were collected by total feces collectionmethod, the contents of dry matter （DM）, crude protein （CP） and crude fat （EE） were measured, and the nutrient digestibility was calculated. Blood samples were collected at the end of thetest and the contents of blood glucose（GLU）, triglyceride（TG）, cholesterol（CHO）, high density lipoprotein cholesterol（HDL）, low density lipoprotein（ALP）, aspartate aminotransferase（AST） , alaningenase（LDH） were measured. The results showedgroup Ⅱ was significantlygroup, VA could improvehigher than that in group Vthe digestibility of nutrientscholesterol（LDL）, alkaline phosphatasenotransferase （ALT） and lactic dehydro 1）Final weight and average daily gain in（P〈0.05）. 2） Compared with control（P〈0.05）, group Ⅱ was all the best.3） VA had no significant effects on GLU and CHO （P〉0.05）, TG content in group V was sig nificantly higher than that in group Ⅱ （P〈0.05）. HDL content in group IV and V were significantly lower than that in the other groups （P〈0.05）. LDL content in group I was the lowest,which was significantly lower than that in group Ⅳ and Ⅴ （P〈0.05）. 4）Serum ALP, AST,ALT and LDH levels were significantly affected by dietary VA （P〈0.05）. ALP content had asignificant difference between group V and control, group Ⅲ, Ⅳ （P〈0.05）. Concentration ofserum AST was significantly decreased in group Ⅱ, which was significantly lower than that in i, group Ⅳ,Ⅱ （P〈0.05） , groin group V was sino significant diffegnificantly lower thanfences between the contration of ALT in group）. Concentration of LDH that in group Ⅰ, Ⅱ, Ⅲ（P〈0.05）, whereas there wasntrol group and group Ⅳ （P〈0. 05）. Under the experiofVAwith 5 000 80 000 IU·kg^-1 in diet could improvee vitamin A supplementation could negatively affectssearch is needed to determine the effect mechanism of exe growth of minks.