Mechanism Of Immunotoxicity Induced By Deoxynivalenol In Weanling Piglets

Deoxynivalenol(DON)is one of the most common mycotoxins in the world.It has many toxic effects,such as neurotoxicity,cytotoxicity and immunotoxicity.In order to study the immunotoxicity mechanism of DON,This 30 healthy weanling piglets,they were randomly divided into 3 groups,with 10 piglets in each group.The piglets in the control group were fed with basal diet;piglets in low dose group and high dose group were fed with 1 mg/kg DON diet and 2 mg/kg DON diet.The trail was conducted for 60 days.At 0,14,28,42 and 60 d of the experiment,all piglets was selected and the blood samples were collected from the anterior vena cava,serum was isolated for measuring the cytokine,lipid peroxidation and physiological and biochemical indexes.At the same time,the body weight of weanling piglets(BW)was weighed.Calculating the average weight,daily average feed intake(ADFI),average daily gain(ADG)and feed ratio(F/g)were calculated.After the experiment,5 piglets in each group were randomly selected to be slaughtered.The intestinal mucosa was preserved with liquid nitrogen and the level of secretory immunoglobulin A(SIgA)was detected.The intestinal segment was preserved in 4% polyformaldehyde and liquid NIT.The positive expression of SIgA,IgM and IgG in the small intestine and the expression of IgA,IgM and IgG mRNA in the small intestine were measured.The results showed that:1.Compared with the control group,the BW of piglets in high dose group were decreased significantly at 60 d(P<0.05).At 14-28 d,the ADG of piglets in the experimental group were decreased significantly(P<0.05),at 28-42 d,the ADG of piglets in the high dose group were decreased significantly(P<0.01),and the low dose group were decreased significantly(P<0.05),and the ADG of the piglets in the experimental group were decreased significantly(P<0.01)at 42-60 d.In 28-42 d,the ADFI of piglets in high dose group were decreased significantly(P<0.01),and the ADFI of piglets in low dose group were decreased significantly(P<0.05),and the ADFI of piglets in the test group were decreased significantly(P<0.01)at 42-60 d.14-28 d,the F/G of high dose group was increased significantly(P<0.05),and at 28-42 d,the F/G of piglets in the experimental group was increased significantly(P<0.01).The toxicity of DON high dose group was higher than that of low dose group.Compared with the low dose group,the BW of piglets in high dose group were decreased significantly at 60 d(P<0.05).At 28-60 d,the ADG of piglets in high dose group were decreased significantly(P<0.01).At 28-42 d,the ADFI of high dose group were decreased significantly(P<0.05);at 42-60 d,the ADFI of piglets in high dose group were decreased significantly(P<0.01).At 28-42 d,the F/G of the high dose group was increased significantly(P<0.05).2.DON can affect the serum biochemical indexes of weanling piglets,destroy the homeostasis of the internal environment,and damage the immune organs,thus hindering the growth and development of piglets.Compared with the control group,the contents of AST in high dose group were decreased significantly(P<0.05),the contents of ALP were increased significantly(P<0.01),and the contents of ALP in low dose group were increased significantly(P<0.05).The serum contents of γ-GGT in high dose group were significantly reduction(P<0.05).Serum content CREA in high dose group were increased significantly(P<0.01),and increased significantly in low dose group(P<0.05).The levels of serum α-AMY in high dose group and low dose group were increased significantly(P<0.01).The serum LPS was significantly increased in high dose group(P<0.05).The serum CK was significantly increased in high dose group(P<0.05).Compared with low dose group,the serum contents of γ-GGT in high dose group were decreased significantly(P<0.05),while CREA and CK were increased significantly(P<0.05).3.Comparison with the control group,the levels of IFN-γ,IL-2,IL-4 and IL-6 were decreased significantly at 42 d(P<0.05).At 60 d,the IFN-γ,IL-2,IL-4 and IL-6 levels of piglets in the test group was significantly reduced(P<0.01),and the situation of the piglets in high dose group were significantly lower than those of the low dose group(P<0.05).The serum SIgA,IgM and IgG levels in high dose group were decreased significantly(P<0.01),and decreased significantly in low dose group(P<0.05).Serum C3 and C4 levels were decreased significantly in high dose group and low dose group(P<0.05).4.Compared with the control group,the activities of SOD,GSH-Px and CAT were decreased significantly(P<0.05 or P<0.01)and the contents of MDA wew increased significantly in treatment group(P<0.05 or P<0.01).5.Compared with the control group,the SIgA levels in duodenum mucosa of the high dose group were significantly decreased(P<0.05),and the SIgA levels in jejunum mucosa of the high dose group were significantly decreased(P<0.05),and the level of ileum SIgA in high dose group was significantly reduced(P<0.01),however the levels of the ileual SIgA in the low dose group were significantly decreased(P<0.05).The positive expression of SIgA,IgM and IgG protein in small intestinal tissues was significantly reduction(P<0.05 or P<0.01),and the mRNA relative expression of IgA,IgM and IgG in all segments of the intestines was significantly decreased(P<0.05 or P<0.01),and the intestinal mucosal immunity of weaned piglets was reduced.In conclusion,DON can decrease the growth performance,reduce the immune function and antioxidant capbility of weaned piglets,and weaken the intestinal mucosal immune function.The toxic effect of DON high dose group was more obvious than that of DON low dose group in wealing piglets.