Effect Of Nano Copper Oxide And Copper Sulfate On Several Immune Factors In The Weaned Piglets

Copper, as a necessary microelement for the body activities, participates in the growth, digestion, blood and immune of the body. However, farmers blindly add high coppers to livestock production and lead to animal poisoning; environmental pollution and so on because the high coppers have antibacterial effects and can promote the growth of animals. It is reported that compared with other coppers, the nano copper oxide has become a feasible source of copper because of its small size, high activity, easily absorbing and so on. In this study, we discuss the different doses and forms of copper on the effects of blood immune parameters, cytokines and intestinal immune-related genes in weaned pigs. This will provide references for screening and rational use of nano copper source which will replace copper sulfate in livestock production.We choose21day-old, healthy and weaned piglets which have similar weight and are from binary hybrid (DⅣ x White) to randomly divide into7groups. Experiment group1was fed basal diet which include5mg/kg copper con as the blank control group. Experiment group2-4respectively add50,100,200mg/kg Cu (added in the form of CuSO4·5H2O) on the basis of basal diet as copper sulfate group. Experiment group5-7group respectively add25,50,200mg/kg Cu (add in the form of nanometer copper oxide) on the basis of basic diet. We study the effects of different doses and forms of copper source on the immune factors IgM, IL-2, TNF-a of the blood and TLR-2, TNF-a expression of intestinal immune-related genes by these different groups of weaning piglets.The results showed that compared with the control group, the content of IL-2in serum of weaning piglets rise in the copper sulfate group,25mg/kg and50mg/kg nano copper oxide group (P<0.05). And the trend of IL-2increasing was more obvious with the increase of days or dosages of additional copper. The difference of50mg/kg copper sulfate group and50mg/kg nano copper oxide group was significant (P<0.01), and the content of IL-2of nano copper oxide group was17.3%higher than copper sulfate group. Thus the result indicated that the form of nano copper oxide was better absorbed and utilized than other forms in the body. The content of IL-2in serum was considered as an ideal identification of copper nutrition in body. Compared with control group, there was no significant difference for the content of IgM in copper sulfate group, copper oxide nanoparticles of25mg/kg and50mg/kg group (P>0.05). On the contrary, the content of IgM of200mg/kg copper oxide nanoparticles had the significant difference (P<0.05), and was decreased. The TNF-α content of serum in50mg/kg copper oxide nanoparticles group was significant difference (P<0.05) compared with control group, but there were no significant difference in other groups. The content of TNF-α was decreased with the increase of the dosage of additional copper. The copper oxide nanoparticles group was7.2%lower than copper sulfate group at50mg/kg dosage.In this study, we detect the expression of TLR2and TNF-α gene by quantitative PCR in different treatment groups. In duodenum, ileum and cecum of the piglets, the expression of TLR-2gene was significantly higher than the control group (P≤0.05) in different time stages of200mg/kg copper sulfate group and200mg/kg copper oxide nanoparticles group. The too high coppers don’t improve the immunity of piglets. Compared with28day-old weaned piglets, the expression level of TLR2gene from different sources and different doses of copper added group declined significantl-y in35day-old piglets. In the50mg/kg added dose group, the express level of TLR2gene in nano-copper oxide group was significantly lower than copper sulfate groups. Compared with the control group, TNF-α gene expression of the low-dose copper sulfate and copper oxide nano-particles decreased, while TNF-a gene expression of20Omg/kg copper sulfate and200mg/kg nano-copper oxide group has increased significa-ntly (P<0.01). Meanwhile, in the different copper sources added50mg/kg group, TN F-α expression level of the nano-copper oxide group piglets was significantly lower than copper sulfate group (P<0.01).Thus, under the experimental conditions, nano-copper oxide is more conducive the body’s absorption and utilization than copper sulfate. Adding50mg/kg copper oxide nano to basal diet is appropriate. It can not only significantly improve the immune function of piglets, but also reduce the extent of damage for the piglets. However, the levels of IL-2and IgM of the piglet blood reduced and the expression levels of TLR-2and TNF-a significantly increased when the dosage of nano-copper oxide was added to200mg/kg,. It indicated that the body has been damaged because of adding high copper. So the additive nano-copper oxide dose should be less than200mg/kg.