Effects Of Different Zinc Sources And Levels On Copper,Iron And Zinc Concentrations In Milk Of Sows And Organs Of Neonatal Piglets

This experiment was conducted to evaluate the effects of different zinc sources and levels on the copper,iron and zinc concentrations in colostrum and milk of sows and liver,kidney,muscle of neonatal piglets after birth to determine the appropriate level of zinc addition in the diet for late gestation sows,to realize the effective utilization of resources,in order to provide theoretical basis for the suitable addition of zinc in the stage of late-gestation sows.At day 80 of gestation,fourty eight sows(Landrace ×Yorkshire)with similar parity(3 to 4 fetal)were randomly divided into six groups with eight replicates per group.The experiment was divided into two stages:gestation and lactation.In the gestation period,the control group(group 1)was fed a basal diet(premix not extra zinc),while other experiment groups(group 2,group 3,group 4,group 5,group 6)were added 50 mg/kg ZnSO4·H2O,25 mg/kg ZnSO4·H2O+25 mg/kg Zn-Met,50 mg/kg ZnSO4·H2O+25 mg/kg Zn-Met,25 mg/kg ZnSO4 H2O+50 mg/kg Zn-Met and 100 mg/kg ZnSO4 H2O(calculated by zinc),respectively.In lactation period,all groups were fed a diet(100 mg/kg ZnSO4·H2O).The experiment began on the eightieth day of gestation of sows and ended on the day 21 of lactation.The results showed as follows:(1)dietary supplementation with 25 mg/kg ZnSO4·H2O+25 mg/kg Zn-Met,50 mg/kg ZnSO4 · H2O+25 mg/kg Zn-Met,25 mg/kg ZnSO4·H2O+50 mg/kg Zn-Met and 100 mg/kg ZnSO4·H2O significantly increased(P<0.05)the content of zinc in colostrum,but had no effect on the content of iron and copper in colostrum(P>0.05).(2)Cu,Fe and Zn concentrations in mature milk were not significantly affected by dietary zinc sources and levels(P>0.05).(3)dietary supplementation of 50 mg/kg ZnSO4·H2O,25 mg/kg ZnSO4 ·H2O+25 mg/kg Zn-Met,50 mg/kg ZnSO4·H2O+25 mg/kg Zn-Met,25 mg/kg ZnSO4 H2O+50 mg/kg Zn-Met and 100 mg/kg ZnSO4·H2O significantly increased(P<0.05)the zinc and iron concentrations in the liver of neonatal piglets.Compared with dietary supplementation with 50 mg/kg ZnSO4·H2O,dietary supplementation with 25 mg/kg ZnSO4·H2O+25 mg/kg Zn-Met,50 mg/kg ZnSO4·H2O+25 mg/kg Zn-Met,25 mg/kg ZnSO4 H2O+50 mg/kg Zn-Met and 100 mg/kg ZnSO4 H2O significantly increased(P<0.05)zinc concentration in the liver of neonatal pigs.(4)dietary supplementation of 50 mg/kg ZnSO4·H2O,25 mg/kg ZnSO4·H2O+25 mg/kg Zn-Met 50 mg/kg ZnSO4·H2O+25 mg/kg Zn-Met,25 mg/kg ZnSO4·H2O+50 mg/kg Zn-Met and 100 mg/kg ZnSO4.H2O significantly increased(P<0.05)the zinc concentration in the kidney and muscle of neonatal piglets.Dietary supplementation of 25 mg/kg ZnSO4·H2O+50 mg/kg Zn-Met significantly increased(P<0.05)the iron concentration in the kidney of neonatal piglets.(5)no significant difference was observed in copper concentration in liver,kidney and muscle of neonatal piglets affected by dietary zinc sources and levels.Based on the current results,dietary supplementation with zinc sources improved zinc concentration in liver,kidney and muscle of neonatal piglets and colostrum.It is concluded that dietary supplementation of 25 mg/kg ZnSO4·H2O+25 mg/kg Zn-Met,50 mg/kg ZnSO4.H2O+25 mg/kg Zn-Met,25 mg/kg ZnSO4·H2O+50 mg/kg Zn-Met and 100 mg/kg ZnSO4·H2O have similar results.