维生素A水平对生长猪生产性能、肝脏维生素A含量和血清免疫参数的影响

试验研究饲粮添加不同水平维生素A(VA) (0、1300、2600、5000、10000、15000IU/kg)对22 -50kg生长猪生产性能、胴体品质、胴体无脂瘦肉增重、肝脏和血浆中VA含量、血清免疫参数的影响。结果表明 ,添加VA1300 -10000IU/kg 提高了日增重 (P>0.05)、极显著地降低料重比 (P<0.01) ;但VA添加水平从1300IU/kg增加至10000IU/kg,料重比显著提高 (P<0.05) ,采食量也极显著提高 (P<0.01)。各组屠宰率、瘦肉率、脂肪率、背膘厚、胴体瘦肉成分都无显著差异 (P>0.05) ,眼肌面积则随VA水平的升高而趋于增大(P>0.05)。胴体瘦肉和无脂瘦肉日增重在添加VA1300IU/kg 和10000IU/kg两组间很接近 ,而且优于其它组 (P<0.05)。随着VA水平的提高 ,肝脏中VA含量极显著提高 (P<0.01) ,至添加VA10000IU/kg组最高 ,之后略下降 ;添加VA有使血浆中VA含量升高的趋势 (P>0.05)。各组血清中IgG、IgA、IgM含量都无显著差异 (P>0.05) ,添加VA使T淋巴细胞中CD3+ 和CD8+ 亚群比例趋于升高 (P>0.05),随着添加VA水平提高 ,血清T淋巴细胞中CD4+/CD8+比值趋于下降 ,至添加VA10000IU/kg 组最低 ,在VA15000IU/kg 组又明显上升 (P>0.05)。以肝脏中VA含量为指标 ,生长猪VA适宜水平为在基础饲料上添加10000IU/kg ,但根据生产性能等其它指标 ,添加1300IU

EFFECTS OF VITAMIN A LEVEL ON PERFORMANCE, LIVER VITAMIN A CONCENTRATIONS AND SERUM IMMUNE PARAMETERS OF GROWING PIGS

The trial was conducted to evaluate the effects of different dietary vitamin A levels(added vitamin A 0,1300,2600,5000,10000,15000IU/kg respectively to the basal diet)on performance,carcass traits,lean compositions,lean gain,liver and plasma vitamin A concentrations and serum immune parameters of growing pigs weighing from 22 to 50 kg.The results showed that daily gains trended to increase(P>0.05),feed to gain ratio decreased very significantly(P<0.01)as adding vitamin A 1300-1000IU/kg to the basal diets.Feed to gain ratio and feed intake increased significantly when increasing vitamin A addition from 1300IU/kg to 10000IU/kg.Dressing percentage,lean meat percentage,fat percentage,backfat thickness and lean compositions had no differences between all treatments(P>0.05),loin-eye area trended to increase when dietary vitamin A levels increased (P>0.05). As adding vitamin A 1300IU/kg and 10000IU/kg to basal diet,the growing pigs had higher lean gain and fat-free lean gain than other pigs(P<0.05).Liver vitamin A concentrations increased very significantly(P<0.01),plasma serum vitamin A concentrations trended to increase(P>0.05)when vitamin A addition increased,and the liver vitamin A concentrations were the highest when the vitamin A addition was 10000IU/kg.Serum IgG,IgA,IgM concentration had no difference between all treatment(P>0.05).Percentage of CD3+ and CD8+ in T lymphocyte trended to increase as adding vitamin A to the basal diet.CD4+/CD8+ratio in T lymphocyte trended to decrease when increasing vitamin A addition from 0 to 10000IU/kg,but to increase when increasing vitamin A addition from 10000IU/kg to 15000IU/kg.It was concluded that the optimum vitamin A level for growing pigs was 10000IU/kg for the best liver vitamin A concentration,and was 1300IU/kg for other performances.