Comparative Study Of Copper Intestinal Injury And Transport In Goats And Sheep

Copper is a necessary transition metal element in animal life activities,and its reductase is involved in aerobic respiration,neurotransmitter synthesis and iron metabolism,et al.Although moderate amounts of copper can promote animal growth,improve immunity and increase feed intake,the lack and excess of copper seriously affect the health and production of animals.Goats and sheep belong to same species with different cultivars,however,their sensitivity to copper is very different.In this paper,different levels of copper were added to the diet to observe the related indexes of blood copper in goats and sheep,the copper level in different intestinal segments and parameters related to intestinal tissue injury,combined with intestinal copper transporters and mRNA expression of copper chaperone factor to study the effects of copper level on intestinal in goats and sheep,to explore the characteristics of intestinal copper transport in goats and sheep.This study provides a theoretical basis for the mechanism of copper metabolism in the intestinal tract of goats and sheep.1.Experiment 1:Effects of dietary copper levels on the homeostasis of copper in goatsFifteen castrated goats(with initial body weight of 20±1.5 kg)were used in a randomized block design experiment to determine effects of dietary copper levels on the homeostasis of copper in goats.Goats were fed diets two times at 07.00,and 16.00 hours daily with 1 to 3 treatments during the experimental periods(60 d): no supplementation of CuSO4·5H2O(control group,CCu0),25mg/kg ·time of CuSO4·5H2O(CCu25),100mg/kg ·time of CuSO4·5H2O(CCu100).On day 59,20 mL blood samples were collected at 06.00 and 14:00 hours before the feeding.At the end of the trial(60 days),all goats were euthanized,and tissue samples were taken.Serum copper level,ceruloplasmin activity,indicators related to intestinal injury,copper level in different intestinal segments,activities of enzymes associated with copper transportation such as alkaline phosphatase,glutathione were detected.In addition,Morphological indexes of intestinal segments,mRNA expression of intestinal immune factors,two tight junction proteins and copper transporters were determined.The results were as follows:(1)The copper content in serum and intestinal segments was positively correlated with dietary copper supplementation level,the activities of SOD and ALP enzymes and tissue copper level in CCu100 were significantly higher than the other two groups(P< 0.05);(2)the VCR and two tight junction protein in the CCu25 group in different intestinal segments were significantly higher than the other two groups(P< 0.05),while the HIS of TLR2 and TNF-? were in the opposite direction.The activities of ALP,GSH-Px and ZnCu-SOD enzymes were significantly different from those of the rest two groups(P< 0.05);(3)the mRNA expression of ATOX1 and two copper transporters in CCu25 group were significantly higher than the other two groups(P< 0.05),and mRNA expression of MT in CCu100 was significantly higher than the other two groups(P< 0.05).2.Experiment 2: Effects of dietary copper levels on the intestinal injury and copper transportation in sheepThe experiment design is the same as experiment 1 except for the animal,sheep were used in this experiment.Sheep were fed diets two times at 07.00,and 16.00 hours daily with 1 to 3 treatments during the experimental periods(60 d): no supplementation of CuSO4·5H2O(control group,CCu0),10mg/kg ·time of CuSO4·5H2O(CCu10),25mg/kg ·time of Cu SO4·5H2O(CCu25).The results showed that :(1)the activities of CP,CuZn-SOD and ALP in the serum increased significantly with the copper level increase(P< 0.05),and the copper level in OCu25 except for in the ileum were significantly higher than other two groups(P < 0.05);(2)the VCR in the jejunum and in the ileum were significantly higher than the other two groups(P< 0.05),while the VCR and mRNA expression of two copper-partner protein in OCu10 were significantly lower than the other two groups(P< 0.05).The activities of enzymes LAP and ZnCu-SOD and the mRNA expression of TJP were significantly higher than the other two groups(P< 0.05),while the his of TLR2 and TNF-? were significantly lower than the other two groups(P< 0.05).The activity of GSH-Px in the duodenum was significantly higher than the other two groups(P< 0.05).In OCu25,the activities of these three enzymes were significantly different in the duodenum and in the jejunum other than in the ileum(P< 0.05).The expression of Claudins in OCuO was significantly higher than the other two groups(P< 0.05),while it was significantly higher than the other two groups in OCu10(P< 0.05);(3)the mRNA expression of COX17 and ATOX in OCu10 were significantly higher than the other two groups(P< 0.05),while the mRNA expression of ATP7 were significantly higher than the other two groups in the duodenum and in the jejunum(P< 0.05).The expression of MT in OCu25 was significantly higher than that in the OCu0 group(P< 0.05).3.Experiment 3: Comparative study on the copper intestinal injury and transportation in goats and sheepThe serum ALP activity in OCu25 group was significantly higher than the CCu0 group(P < 0.05),while the CuZn-SOD activity in CCu0 was significantly higher than the OCu0(P< 0.05).At the same supplementary copper level with 25mg/Kg,the copper level in sheep were significantly higher than in goats in the duodenum,in the jejunum and in the ileum(P< 0.05);(2)the VCR in goats in intestine were significantly higher than in sheep(P< 0.05),while the activities of enzymes ALP,GSH-Px and ZnCu-SOD in goats were significantly higher than in sheep in the duodenum and in the jejunum(P< 0.05);(3)when the copper was added with 25mg/Kg,the mRNA expression of Claudins in different intestinal segments in goats were significantly higher than in sheep(P< 0.05),whie the mRNA expression of TJP were significantly higher in the jejunum and in the ileum(P< 0.05).The HIS of TLR2 and TNF-? were significantly higher in goats(P< 0.05);(3)the mRNA expression of COX17,ATOX1 and CTR1 were were significantly higher in goats in different intestinal segments compared to sheep with 25mg/Kg supplementation(P< 0.05),while the mRNA expression of ATP7 A were significantly higher in goats in the duodenum,in the jejunum and in the ileum(P< 0.05).Above all,diet supplied with 10mg/kg and 25mg/kg CuSO4 could contribute to the intestinal function in goats and sheep,and promote the absorption and transport of copper in the intestine.Diet supplied with 25mg/kg and 100mg/kg CuSO4 could lead to the intestinal injury in goat and sheep,it is harmful to copper absorption and translocation in intestinal tract.