Effect Of Cysteamine On The Rate Of Early Successful Weaning And Immunity Of Calves

1 The effect of feeding cysteamine on the successful weaning rate and growth parameters of calvesThe experiment was conducted in Nanjing Weigang campus diary farm.36 Holstein calves were allotted, based on age and body weight, to control(n=18, BW= 37.68±0.88kg) and experiment (n=18, BW=37.59±0.86kg) groups randomly. Both groups were fed according to the strategy of dairy farm, with the experiment group supplemented by CT2000 (60mg/kg·BW·d). The experiment was actualized from 8-day to 50-day old of the calves. The calves were weaned at 45-day old and the weaning process finished at 50-day old. The results showed that there were no differences between two groups in dairy body weight neither the body size. But the rate of successful weaning of experiment group was 100%, which is 17% higher than the control group. This predicted that the cysteamine had positive effect on the early weaning of calves.2 The effect of feeding cysteamine on the immune abilities and concentration of serum Insulin of calvesExperiment 1:The effect of feeding cysteamine on transformation of peripheral blood lymphocytes and concentrations of serum IL-2,Glutathione and Insulin in pre- and post- weaning calvesBlood samples were taken from calves at 28-day old,45-day old and 50-day old. We tested the concentration of IL-2,GSH and Insulin in serum. Transformation of peripheral blood lymphocytes was tested at 50-day old. The rate of transformation of peripheral in 50-day old calves was significantly enhanced in experiment group(P<0.05); the concentration of serum IL-2 and Insulin in 45-day old calves was remarkably higher in experiment group(P<0.05); the concentration of serum GSH was evidently increased in experiment group(P<0.05), too. The results indicated that feeding cysteamine improved the immune abilities and antioxidative capability of calves to elevate the successful weaning rate. Meanwhile, the energy metabolism of calves was also affected by feeding cysteamine.Experiment 2:In vitro study on the positive effect of cysteamine on the transformation of peripheral blood lymphocytes and antioxidative capability in neonatal calves1) In vitro, lymphocytes were separated from the peripheral blood in five newborn male Holstein calves and four 45-day female Holstein calves. The experiment wells were treated with cysteamine (at the concentration of 0.5 mM). The transformation of lymphocytes was tested after 72h. The result showed that the transformation of T lymphocytes was significantly increased (P<0.05).2) In vitro, we separated lymphocytes from four 45-day female Holstein calves. The experimental wells were treated with cysteamine (at the concentration of 0.5 mM), the intracellular GSH of T lymphocytes was detected after 72h. We founded that the concentration of intracellular GSH in experimental groups was observably hoisted (P<0.05).3) In vitro, we separated lymphocytes from four 45-day female Holstein calves. The experimental wells were treated with IGF-1 (at the concentration of 25 ng/mL) or Insulin (at the concentration of 60 ng/mL). The transformation of lymphocytes was tested after 72h. The result showed that the transformation of T lymphocytes was significantly increased (P<0.05) in the experiment groups.This study illuminated that cysteamine stimulate the proliferation of peripheral blood lymphocytes directly in calves, so does in the newborn calves in vitro; or exert its function indirectly via IGF-1 or Insulin and by increasing intracellular GSH in lymphocytes.In conclusion, feeding cysteamine could improve the successful early weaning of calves. The mechanism was relative to the improvement of immune ability in calves.