Effects Of Different Zinc Sources And Levels On Trace Elements Metabolism And Zinc Related Gene Expression Of Weaned Piglets

The experiment mainly studied the effects of zinc methionine(Zn-Met)with the zinc sulphate monohydrate(ZnSO4·H2O)in combination on growth performance,blood physiological biochemical indices,the apparent digestibility of trace element,zinc related gene expression in weaned piglets in order to determine the optimal combination model of organic and inorganic zinc,and then provide theory basis for meeting the needs of the growth of piglets by low level zinc,reducing emissions of fecal zinc in aquaculture production.A total of weaned thirty five piglets(Duroc×Landrace×Largewhite,35 day-old)with an average of(10.69±0.26)kg were randomly allotted to five groups with seven replicates in each groupand and 1 piglet per replicate.Basal diet feed the same(premix not extra zinc);Treatments:?)Control group(basal diet+100 mg Zn/kg diet from ZnSO4·H2O),?)75 mg Zn/kg diet from ZnSO4·H2O + 12.5 mg Zn/kg diet from zinc-Met,?)50 mg Zn/kg diet from ZnSO4·H2O + 25 mg Zn/kg diet from zinc-Met,?)25 mg Zn/kg diet from ZnSO4·H2O + 37.5 mg Zn/kg diet from zinc-Met,?)50 mg Zn/kg diet from zinc-Met.The trial was conducted for 49 d,including pilot test period 7 d and formal trial period 42 d.The results showed as follows: 1)Compared with control group,the average daily feed intake,average daily gain and the feed conversion ratio of test groups added zinc methionine had no significant difference(P>0.05).2)The nutrient digestibility of the groups added zinc methionine were not significantly different with the control group(P>0.05).3)Compared with group separate added zinc methionine or zinc sulfate,white blood cell content and lymphocyte content of groups added zinc mixed increased,and the group added 50 mg/kg zinc sulfate with 25 mg/kg zinc methionine had increased significantly than other groups(P<0.05).4)Compared with control group,serum zinc and manganese content,zinc content in the liver and pancreas of groups which feed zinc mixed were significantly higher(P<0.05);fecal zinc excretion of test groups were decreased significantly(P<0.05).It showed that the mixed use of zinc methionine with zinc sulfate could improve weaned piglets' trace elements in serum and the organization and significantly reduced fecal zinc excretion.5)The thymus,spleen,and pancreas index number of the control group were lowest among all groups,the thymus,spleen,and pancreas index number of groups added zinc mixed were significantly higher than that of the control group(P<0.05);and serum MDA of those reduced significantly(P<0.05).These justify zinc mixed could improve piglets' anti-stress ability.6)Fodder mixed with methionine zinc and zinc sulfate significantly increased MT mRNA expression in all tissues and CRP mRNA in the kidney and spleen;compared with control group,HP mRNA expression and AGP mRNA expression in the pancreatic and kidney,SSA mRNA expression in all tissues significantly increased,with increasing with zinc methionine level(P<0.05),these justify the mixed use of zinc methionine with zinc sulfate could improve the secretion of MT in different organisations,and zinc methionine could induce more APP gene expression,improve piglets' anti-stress abilityIn conclusion,fodder mixed with zinc methionine and zinc sulfate improves the weaned piglets' body zinc nutrition level.Compared with the single use of zinc sulfate,the mixed use of zinc methionine with zinc sulfate can not only reduce feed add zinc levels,but also improve weaned piglets' trace elements in serum and the organization,significantly reduce fecal zinc excretion,and trace elements emission reduction effect of fodder mixed with 50 mg/kg zinc sulfate and 25 mg/kg zinc methionine reduction effect is the best of all;the mixed use of zinc methionine with zinc sulfate can improve MT mRNA expression,and APP mRNA expression increase with level of zinc methionine.