Effect Of Various Selenium Doses On Chromium(?)-induced Nephrotoxicity In Chickens

In recent years,the application of heavy metal chromium and its compounds in all walks of life,the heavy metal pollution problems are more and more serious.The body damage and carcinogenicity caused by chromium poisoning has become the focus of attention.There are lots of research on chromium in livestock and poultry nutrition and toxic,but the chromium on the body damage mechanism is not clear.In addition,studies have shown that sodium selenite has a mitigating effect on heavy metals.There are many studies on chromium poisoning in mice and rats,but the research on chromium poisoning in poultry and the effect of selenium on chitosan poisoning is relatively few.In this study,the effect of different doses of selenium on renal toxicity induced by chromium poisoning was investigated.The acute experiment through lavage was done to calculate the median lethal dose(LD50)of potassium chromate by Horn method,and the LD50 was 369 mg/kg body weight,and 6% LD50 was used as the challenge dose,that is 22.14 mg/kg body weight.One hundred and five male chickens were randomly divided into seven groups: The 6 experimental groups received K2Cr2O7 alone or in combination with 0.31,0.63,1.25,2.50,and 5.00mg/kg for 42 days.The challenge route was fed with potassium dichromate solution and the control group was fed with distilled water.The levels of MDA,T-SOD,GSH,Ca2 +-ATP were measured at the time of 14 days,28 days and 42 days,respectively.Exposure to Cr(VI)significantly increased MDA contents and organ coefficient,whereas decreased T-SOD activities,Ca2+-ATPase activities,mitochondrial membrane potential and GSH contents,the activity of GSH,T-SOD increased,the activity of Ca2+-ATPase and the mitochondrial membrane potential were restored by Se supplement 0.31 mg/kg,0.63 mg/kg and 1.25mg/kg,in which supplement with 0.63 mg/kg Se developed more effectively than the other two groups.on the contrary,in the groups of Se supplement with 2.50 and 5.00 mg/kg,theabove indicators were not ameliorated and even exacerbated.The histopathology of renal tissue showed that the main lesion was in the renal tubules,and the activity of Ca2+-ATPase was decreased and the mitochondrial membrane potential was decreased.Dissolution in the tubular epithelial cells was clearly observed in the kidney of K2Cr2O7-treated chickens.Moreover,renal tubules showed Swelling and narrowed lumen;and renal capsule lumen largened.In the Cr(VI)+Se group,renal damages were markedly reduced.Moreover,The Group IV presented histology images of kidney similar to that observed in the control group,only showing slight hemorrhage.However,in the Group VI,renal tubules showed severe swelling,enlarged lumen and necrosis in the tubular epithelial cells.Experimental results show that Cr(VI)can cause oxidative damage of kidney in male chicken,pathological changes,and Se of certain dose possess the protective effects against Cr(VI)-induced nephrptoxicity.