Effect Of Zinc In Yeast Culture On Growth Performance And Immunity Of Piglet

This experiment was conducted to study the effect of zinc in yeast culture and zinc oxide added into diets on piglet growing performance, immunity and relative enzyme activity etc. and if zinc in yeast culture was a more ideal substance and what was an suitable concentration of zinc in yeast culture as a feed additive.Twenty piglets their average daily gain were 14.3kg were used in a complete random of single factor design to investigate the effect of zinc in yeast on growing performance, immunity and the activity of the enzyme related to zinc on 7^th,8^th,9^th and 10^th week of age of piglets. Its were divided into 4 groups, with 4 repetitions in each in the experimental groups. And each piglet was raised in a single fold and water available at ad. Each group was fed the diets with 50,100,200mg/kg zinc in yeast culture besides basic diet, the control group was fed basic diet with zinc oxide (zinc, 2600mg/kg).The experimental period of this study was 21 days. Feed/water was 1:1 and 3 times were fed every day.The results of effects of zinc in yeast culture on growing performance of piglets showed:There were not significantly (P>0.05)different among the indexes about average daily gain, feed/gain and diarrhoea rate etc.. But the experimental group 3 increased by 24.64% than the control and 30.81 than the experimental 1 in average daily gain. And the more average daily gain was enhanced, the more the density of zinc in yeast culture was dense; It was the same level group3 and the control in feed/gain and the level was lower others groups; Each experimental group (besides group 4)was lower the control in diarrhoea rate and it was lowest when the concentration of zinc in yeast culture was 200mg/kg.No significant (P>0.05) difference was observed among groups about carcass and pork quality.There was significant (P<0.05) difference surveyed on zinc deposited into internal organs of the body and feces between the control and each experimental group. But zinc in muscle was not affected between the control and group 1 and 3, and that was significantly (P< 0.05)decreased in groups 4 than others group.The indexes of internal organs were not affected by the diets with zinc in yeast culture and zinc oxide. But in group3 the liver index number was improved by 17.05% than the control and by 13.14% than group1 The spleen index of group3 was enhanced by 90.9% thangroupl,and 17.59% than the control, and that of group4 was also higher 11.15% than the control. There was only a tendency in the pancreas index number from the control to pass through group 1 to 4.The kidney index of experimental groups was the same level and all lower than the control group.As the results of the effects of zinc in yeast culture on piglets immunity shown:The T lymphocyte transformation ratio of the vein blood of piglets that were fed different concentrations of zinc in yeast culture were: no significant (P>0.05) difference was investigated among all group, but the effect of PHA on the change of T lymphocyte stimulate index was different in differently experimental period. The stimulate index in group3 was increase by 46.05% than the control on 8th week of age of piglet, and that of group3 and the control had all surpassed others group in the end of this trial period.The vein blood B lymphocyte transformation ratio of piglet that were fed different contents of zinc in yeast culture did not have significant (P>0.05) difference observed among different groups. However, the effect of LPS on the change of stimulate index of B cells was enlarged as the animals were growing. To begin with , the stimulate index was biggest in group3, and the index of group4 was less than others group though it also was mild increased. The index of groupl was greater than others group and increased by 32.02% than the control,36.92% than the group4 in the end of this trial.The results of the activity of zinc correlative enzyme indicated:The activity of CuZn-SOD and GSH-Px in serum were not affected by all kinds and concentrations of zinc among different groups. A decreasing tendency was obviously checked about activity of CuZn-SOD and a distinctly increasing tendency about activity of GSH-Px in serum for the experiment was going on. The activity of GSH-Px in serum was enhanced 5.8 times in the control and 10.6 times was increased in the trial groups. The activity of AKP in serum was also tendency heightened from 7th to 10th week of age. And there was only significant difference between group land 4 in 8th week of age.The activity of CuZn-SOD in liver was not significantly (P>0.05) different between the control and group3,but there was a significant difference between the control and others trial groups. The activity of the enzyme was firstly increased and then decreased from groupl to 4 ,and the activity was highest in group3 when the concentration of zinc was 200mg/kg.The activity of CuZn-SOD in pancreas was not significantly (P>0.05) different among different groups, but there was a increasing tendency was checked from groupl to 4,and 39% wasincreased in group4 than group 1. The activity of AKP in kidney was not significantly (P> 0.05) different, too. But there also was a increasing tendency for the contents of zinc in the diets was increasing, and 1.8 times in group4 was enhanced than group 1.To sum up, the average daily gain can be increased, feed/gain and diarrhoea rate can be decreased when the concentration of zinc in yeast culture was 200mg/kg.The deposited ability of zinc in yeast culture was significantly lower than the control (zinc,2600mg/kg)in interval organs. But it was no use to be deposited whether the concentration of the zinc in yeast culture was too dense or not in muscle. Zinc (50 mg/kg,100 mg/kg,200mg/kg) in yeast culture can enhance the lymphocyte transformation ratio, but the concentration of 200mg/kg was great in cell immunity and 50mg/kg was good in body immunity for piglets. No significant difference was investigated whether cell immunity or body immunity. From another aspect, this experiment expressed the vein blood lymphocyte ratio on PHA and LPS had already not changed from 7th to 10th week of age for piglet. That is to say, the immunity system of piglet in this period have been completely developed and the piglet in this period have already had stable immunity function.