Effect Of Different Zinc Sources And Levels On Performance, Blood Biochemical Indexes,Tissue Zinc Concentration And Pancreas Metallothionein Mrna Of Fattening Pigs

This experiment was conducted to investigate the most optimum zinc source and suitable addition level on fattening pigs through feeding experiment, blood biochemical indexes analysis experiment,tissue zinc concentration and pancreas metallothionein mRNA analysis experiment.2x3factorial design was used in this experiment.840fattening pigs, which average weight was about60kg, were allotted randomly to7dietary treatments with6duplicates which included20fattening pigs.7dietary treatments included a basic diet(control group) based on corn-soybean meal and6tested diets which were formed by supplemental with different levels(40,80,120mg/kg) of two sources(zinc sulfate and amino acid chelate zinc).Two fattening pigs in each replicate was slaughtered to collect blood samples and various tissues after56days experiment period. Individual body weight of all pigs and feed consumption per replicate were measured at the0and56day of age.The results indicated that:(1)Production performance:There was no significant difference of the average daily gain(ADG), average daily feed intake(ADFI) and the feed gain ratio(F/G) among zinc sources groups and zinc levels groups.(P>0.05)(2)Blood biochemical indexes:Supplementation with organic zinc (amino acid chelate zinc) had the effect on the glutathione peroxidase (GSH-Px) and serum urea nitrogen(SUN). Compared to the inorganic Zinc groups(Zinc Sulfate), GSH-Px were increased by9.37%(P<0.01), SUN were decreased by5.80%(P<0.05) in organic zinc groups.There was no significant difference of the Cu/Zn superoxide dismutase(CuZn-SOD), malondialdehyde(MDA), total antioxidant capacity(T-AOC), albumin, total protein, IgA,IgM and IgG among zinc sources groups (P>0.05) CuZn-SOD were higher (P<0.01) in fattening pigs fed Zn with120mg/kg and40mg/kg levels compared to those fed the control. GSH-Px were higher(P<0.01) in fattening pigs fed Zn with40mg/kg,80mg/kg and120mg/kg treatments than those fed the control. MDA were higher (P<0.01) in fattening pigs fed Zn with40mg/kg level than in those fed the control or80mg/kg or120mg/kg treatments.T-AOC, SUN, albumin, total protein, IgA,IgM and IgG were not affected by different Zn levels treatment (P>0.05)(3)Tissue zinc concentration:There was no significant difference in Zn concentration of liver,kidney and shin bone among zinc sources groups (P>0.05) Pancreas Zn concentration and blood serum Zn concentration were increased5.27%(P<0.05) and10.14%respectively in fattening pigs supplemented with Organic zinc, compared to fattening pigs receiving inorganic zinc. The zinc concentration in tissue (P<0.01) is increased except shin bone (P>0.05) with the increase of zinc supplementation.(4)Pancreas metallothionein mRNA: There was no significant difference of pancreas metallothionein mRNA among zinc sources and zinc levels (P>0.05) However pancreas metallothionein mRNA were higher in fattening pigs fed Zn with120mg/kg and80mg/kg levels compared to those fed the control or40mg/kg treatments.In conclusion. Under the condition of this experiment, there was no significant difference of production performance and pancreas metallothionein mRNA among zinc sources groups. However, antioxidant ability had enhanced in fattening pigs supplemented with Organic zinc, compared to fattening pigs receiving inorganic zinc or the control,the levels of120mg/kg has the good performance. Though there was no significant difference of Zn concentration in liver and kidney among zinc sources, Pancreas Zn concentration and blood serum Zn concentration were significant difference in fattening pigs supplemented with Organic zinc or inorganic zinc.The results suggest that Zn from Organic zinc was more bioavailable than inorganic zinc.Taking the practical production into consideration, the dietary zinc levels of80mg/kg could be possible to meet the requirement of fattening pigs.