Study On The Effects Of Vitamin A On The Antioxidant Ability Of Beef Cattle And Its Nutrition Monitoring

The research includes three tests. Test 1 studied the influence of different levels of VA to the produce performance of beef cattle, the content of VA of the liver and blood, then drawing the return equation of VA nutrition monitoring. In test 2 and test 3, we studied the influence of different levels of VA to the antioxidant ability, the fibre degradability and the rumen microbe of beef cattle.48 healthy cross-breed(Limousin ×Luxi)beef cattle were selected in the test to study the effect of different levels of VA on produce performance, the content of VA in liver and blood of 12, 16, 24 months age beef cattle. The result showed that the level of VA reaching 2200IU/kg in the diet can meet demands of their growth to the 12 and 16 months age beef cattle,, but 4400IU/kg VA can not make the beef cattle of this age bracket reach the best produce performance; To the 24 months age beef cattle, VA in diet can not influence it to produce performance (P < 0.05) notably. The content of VA in liver and blood is higher than the control group when the level of VA is 2200-4400IU/kg, and the number of this have high coefficient correlation with the content of VA in diet. But the variation tendency that depositing in the muscle of VA is not as good as in the liver and blood is obvious for every ages of tested cattle when the level of VA improves.A trail was conducted to evaluate the effect of dietary vitamin A levels on antioxidant activity of beef cattle. Thirty crossbred beef-cattle (Simmental × Lu-xi) were randomly divided into control group (no VA added) and tested groups (adding 1100, 2200, 3300, 4400, 5500IU/kg VA to the basal diet respectively). The results showed that the activities of GSH-Px and CuZn-SOD and T-AOC were increasing evidently (P < 0.05) as we added 33001U/kg-4400IU/kg VA into the diet. As adding 4400IU/kg-5500IU/kg vitamin A to the diet, the content of MDA decreased remarkably. The T-AOC, the content of MDA and the activities of GSH-Px and CuZn-SOD, all are the proper index to estimate. The nutrition condition of VA, but the T-SOD wasn't the proper index to test the antioxidant of vitamin A. In the trial, the basal level of VA was 3300IU/kg, and the level of vitamin A was 4400IU/kg could more effectively reduce the degree of lipid peroxidation, but all the items showed that the level of VA was 5500IU/kg was against the antioxidation for the beef cattle.4 healthy cross-breed (Limousin×Luxi) ox were selected in the test, which were surgically fitted with permanence cannulate in rumen. The experiment was designed to study the effect of different levels of VA to the MCP, rumen environment and the fibre degradability. The result showed that 2200-3300IU/kg VA can improve the output of MCP and the degradability of NDF and ADF (P<0.05), but VA can not effected the rumen environment (pH and NH3-N) remarkably.