| Selenium is one of necessary trace element for human and animal's health.The appropriate dose of selenium can regulate growth,improve performance and immunity,resist oxadation and stress,postpone aging and antagonize some toxicants or toxic elements.But selenium,especially inorganic selenium,its safety range is very narrow and it is easily to cause acute or chronic poisoning when the dose of selenium is slightly excessive.The current study is developed to aim at the practice problem,found in the process of breeding rabbits,which adding inorganic selenium to diet can result in stunting and hair rarefaction in most New Zealand rabbits from one of the rabbit houses.In order to make clear the reason causing this phenomenon,the selenium levels of the rabbit and the rabbit diet,the antioxidant capacity and the skin hair follicle structure changes of the New Zealand rabbits were detected and evaluated.Through analyzing these indexs,the mechanism of the effect of excessive selenium on the rabbit skin hair growth and development was probed.And the study results can guide people to safely add selenium to the rabbit diet.Experiment 1.The effect of excessive selenium in diet on the selenium content in whole blood and skin of rabbitsTwenty rabbits were fed diet 30 days,10 rabbits in each group.Blood samples were collected from the ear vein of rabbits.Skin samples were scissored from the dorsal skin of rabbits.The right amount ofwhole blood and skin samples(n=10)were detected to assay the selenium content by using the graphite furnace method.The results show that:the blood selenium content of rabbit from the sodium selenite(SS)group,with SS added at the Se level of 0.16 mg/kg,is higher 40.32%than that of the control(C)group,P = 0.043(P<0.05);there is no significant difference in skin tissue of rabbits(P>0.05).Experiment 2.The effect of excessive selenium in diet on the skin hair follicle structure of the New Zealand rabbitTwenty rabbits were fed diet 30 days,10 rabbits in each group.After shearing hairs,the both sides of the scapular skin in rabbits were cut to tile the perforated board and fixed in Bourne's solution for 8-24 h,then dehydrated,made transparent,embedded,sliced into 4 microns.After HE staining,the changes of the skin follicle structure were watched.The results showed that the hair follicles of the C group were arranged regularly,where one primary follicle was surrounded by some secondary follicles regularly arranged.Their ellipse structures were consistent with the structure of normal hair follicles of rabbits.However,the scrambled hair follicles were found and the shape of primary follicle was abnormal in the SS group.Experiment 3.The effect of excessive selenium in diet on the antioxidant capacity of the New Zealand rabbitTwenty rabbits were fed diet 30 days,10 rabbits in each group.Blood was collected through the vein in ear and centrifuged at 3000 g for 15 min to get plasma,and the skin tissues were scissored.The right amount of plasma and skin samples(n =10)were detected to assay the GPx,SOD activity and T-AOC,and the units of MDA using their corresponding assay kits.The results show that:Compared with the control group,the activities of GPx(P<0.01)and SOD(P<0.05)and the T-AOC(P<0.01)in skin tissues of the SS group all significantly lowered,and the MDA levels significantly increased(P<0.05);compared with the control group,the activities of GPx(P<0.01)and SOD(P<0.01)and the T-AOC(P<0.01)in plasma of the SS group all significantly lowered,and the MDA levels significantly increased(P<0.01).Experiment 4.The effect of excessive selenium in diet on the GPx4 and the EGFR protein expression in rabbit skin tissueTwenty rabbits were fed diet 30 days,10 rabbits in each group.Skin samples were scissored from the dorsal skin of rabbits.The GPx4 and EGFR proteins expression levels were detected by Western blotting method.Western blot analysis revealed that GPx 4 and EGFR proteins expression level of rabbit skin in the SS group significantly decreased(P<0.05)in comparison to the control group. |
PDF Full Text Request