Effects Of Vitamin A On Growth Performance And Blood Constituents Of Different Physiological Stage Of Grey Goat

This experiment is conducted to study the effects of different levels of VA on growth performance, antioxidant activities and blood constituents of different physiological stage of Grey goat, so as to determine the optimal amount of VA to improve growth performance, antioxidation and immune function of Grey goat.Forty late pregnancies Grey goats were randomly allocated to four groups for 67 d feeding experiment 1. The four groups of goats were fed a basal diet with supplementation of vitamin A at the levels of 0 (Control), 1100, 2200 or 4400 IU/kg. The results showed that, the activities of T-SOD were significantly increased (P<0.05) by 1100 IU/kg VA. 2200 IU/kg VA increased (P<0.05) the activities of GSH-Px, and decreased the content of MDA. 1100-2200 IU/kg VA increased T-AOC. Supplemented with VA increased (P<0.05) the quantity of white blood cell, granulocyte and lymphocyte. 1100 IU/kg VA significantly increased (P<0.05) the quantity of white blood cell. 2200 IU/kg VA significantly increased (P<0.05) the quantity of red blood cell. Haematocrit was significantly increased (P<0.05) by 2200 and 4400 IU/kg VA. Hemoglobin, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were increased (P<0.05) by 2200 IU/kg VA. 1100 and 2200 IU/kg VA increased (P<0.05) the birth weight of grey goat.Thirty-two multiparous lactating ewes of Grey goat (BW = 35.1±1.1 kg) were divided into four groups of eight with four different supplementing levels of vitamin A (0, 2000, 3000 and 5000 IU kg?1 DM). Ewes were fed in individual lot at ad libitum intake and had free access to water for 35 d feeding experiment. Average daily feed intake and average milk yield of ewes were measured weekly. Blood was obtained every 14 days to evaluate activities of antioxidant enzymes, blood constituents and vitamin A levels in serum. Results showed that: In general, feed intake, milk yield and feed efficiency were not affected by vitamin A supplementation. However, supplementation of vitamin A increased (P<0.05) activities of glutathione peroxidase and total antioxidant capacity, but reduced (P<0.05) concentrations of malondialdehyde in serum of ewes. Red cells number increased linearly (P<0.01) and quadraticly (P<0.01) with incremental amount of vitamin A. Number of lymphocyte, concentration of hemoglobin and haematocrit were increased (P<0.05) by supplementing vitamin A. Serum retinol concentration was higher (P<0.05) for ewes supplemented with vitamin A at 5000 IU kg^-1 than for control ewes, but retinol concentration in milk was not difference (P>0.05) among treatments. Conclusion: Addition of vitamin A improved antioxidant status of lactating Grey goat thereby enhanced their immune function. The optimum level of vitamin A supplementation for this purpose was between 2000 and 3000 IU kg^-1 DM.Forty kids of Grey goat (BW = 8.27±0.94 kg) were used to evaluate the effects of different levels of vitamin A on growth performance, antioxidant status and blood constituents. Kids were divided into four groups of ten with four different supplementing levels of vitamin A (0, 500, 1000 and 2000 IU/kg DM) for 56 d feeding experiment. Kids were fed in individual pen at ad libitum intake and had free access to water. Average daily gain and average daily feed intake of the kids were measured weekly. Blood was obtained every 14 days to evaluate the activities of antioxidant enzymes, blood constituents and vitamin A levels in serum. Results showed that growth rate, feed intake and feed efficiency were not affected by vitamin A supplementation. However, supplementation of vitamin A increased (P<0.001) activities of total superoxide dismutase, glutathione peroxidase and total antioxidant capacity, but reduced (P<0.001) concentrations of malondialdehyde in the serum of kids. Number of white blood cells increased linearly (P<0.001) with incremental amount of vitamin A. Number of lymphocyte, concentration of hemoglobin and the mean corpuscular hemoglobin concentration were also increased (P<0.05) by supplementing vitamin A. Serum retinol concentration was higher (P<0.05) for kids supplemented with vitamin A at 2000 IU/kg than for control kids. These results demonstrated that addition of vitamin A improved antioxidant status of Grey goat thereby enhanced their immune function. The optimum level of vitamin A supplementation for this purpose was between 1000 and 2000 IU/kg DM.All the results showed that supplemtation VA in diet increased the antioxidant activities and immune function of Grey goat. And serum antioxidase and VA concentration could reflect the nutriture of VA in Grey goat of different physiological stage.