Study On The Clinical Implications Of Renal Injury In Broiler Induced By High Protein Diet

Protein plays important role in humans and animals life.Normally,the quantity of protein in the body is in dynamic equilibrium.For successful production of broilers,some breeding enterprises increased to feed protein rich diet,which results excessive protein intake that leads to kidney damage.In broiler,protein rich feeding often result different diseases,such as gout.In the present study,the mechanism of kidney damage induced by protein rich diet was studied by adding different concentration of protein to basal diet.120 feathers of 20-day-old white-feathered chickens were randomly divided into three groups(30 each group).First group was fed with basal diet(protein containing 19%),group ?,? and ? were fed with soybean meal to increase their crude protein content to 22%,25%and 28%,respectively.Water was given ad libitum and the experimental trails were lasted for 14 days.During the experiments,the health states,appetite and defecation of chickens were observed every day.On day 0,7,and 14 after the experimental trials,5 chickens from each group were randomly selected and blood samples were collected from their sub-winged vein.After centrifugation with 3000 rpm for 10 min,the serum was separated and stored in-20? for renal function indexes,and oxidative and anti-oxidative analysis by oxidation function test.At the end of the experimental trials,5 feathers chickens were randomly selected from each group for culling,and the kidneys were immediately removed and stored at-80? after quick freezing with liquid nitrogen to detect the mRNA expression of xanthine oxidase(XOD),and Bcl-2.In addition,the kidneys samples were fixed in formalin and 2.5%glutaraldehyde solution to observe the pathological changes and ultrastructure of renal tissue.The result shows that;1.On day 8th of the experimental trails,the chickens in protein rich group start showing different symptoms such as:depression,supine,febrile joints,decreased appetite,white dung,and wet perianal area.First group had no symptoms with normal feces during the whole experiment period.The chickens in the high protein group began to show disease symptoms on the 8th day of the experimental trials.Compared with the control group,the kidneys of diseased chickens were enlarged,showing flowery pattern,and uric acid deposits were found in the kidney parenchyma and ureter.The normal protein group didn,t show any symptoms of gout and no death occurs in this group.Group ? also shows no mortality during the whole experimental period.In group ?,the statistical death rate was 1,and the mortality rate show a percentage of 3.3%.In group ?,the statistical death rate was 1 with a mortality rate of 3.3%.2.H&E staining showed intact renal tissue in the control group with regular in shape,and no obvious damage was found..In the protein rich diet group,glomerulus atrophy,renal vesicle dilatation,local idflammatory focus,necrosis of some tubular epithelial cells from basal membrane,edema and pink protein were found in the lumen..It was found that the control group had normal cell structure with complete mitochondria,distinct shape and rich glycogen content.The mitochondria in the high protein diet group shows swelling of mitochondria and some mitochondrial ridges were broken.3.On day 0,7 and 14,the renal function indexes were analyzed.On day 7th and 14th compared with the control group,the serum calcium(Ca),and creatinine(CREA),level were increased in the high protein group.The contents of urea nitrogen(BUN)is significantly increased(P<0.01 or P<0.05),but the changes in serum phosphorus(P),magnesium(Mg)content were not statically significant(P>0.05).on day 14th compared with the control group,the contents of uric acid(UA)is significantly increased(P<0.05).4.Compared with the control group,the levels of nitric oxide(NO)and malondialdehyde(MDA)in the serum and renal tissue of high protein groups on day 7th and 14th were increased significantly(P<0.05).The content of hydroxyl free radical(·OH)was significantly increased(P<0.01 or P<0.05).On day 7th and 14th the total antioxidant activity(T-AOC)and glutathione peroxidase(GSH-PX)in the serum and renal tissue of the high protein groups were significantly increased(P<0.05 or P<0.05).The activity of superoxide dismutase(SOD)decreased significantly(P<0.01 or P<0.05).5.On the 14th day of the experimental trials,compared with the control group,the expression of XOD mRNA and Bcl-2 mRNA in renal tissue of high protein group was significantly increased(P<0.01 or P<0.05).In conclusion,high protein diet resulted in pathological changes in renal tissue,with abnormal renal function indexes.It can also increase expression of XOD,Bcl-2 mRNA in renal tissue,increased renal tissue homogenate and serum oxidation.These results show that increased concentration of protein intake decreased antioxidant level due to which the oxidative stress appeared.