| As the main digestive and immune organ in poultry,the intestine plays an important role in ensuring the health and growth of poultry.At present,with the promulgation and implementation of China’s policy to ban antibiotic growth promoters across the board,it has led to a high incidence of intestinal diseases in poultry.Therefore,it is vital to ensure the intestinal health of poultry in production.Sodium humate(HNa)has a promising future as a natural and functional feed additive for poultry production.However,the protective effect of HNa on intestinal damage in broiler chickens has not been reported yet.Therefore,in this experiment,we investigated the protective effect of HNa on intestinal damage in broiler chickens by establishing a model of Salmonella infection in broiler chickens,and provided a scientific basis and theoretical basis for the clinical application of HNa in broiler chickens.In this experiment,75 1-day-old male AA broilers were divided into 5 groups according to the principle of similar body weight,namely the control group(CON group),the model group(MOD group),the low-dose group of sodium humate(L-HNa group),the medium-dose group of sodium humate(M-HNa group)and the high-dose group of sodium humate(H-HNa group),and the experimental period was 24 d.From 1 to 21 d,the CON and MOD groups on 22 to 24 d,broilers in the CON group were given 1 m L of saline daily,and broilers in the MOD,L-HNa,M-HNa and H-HNa groups were given 1×10~9 CFU/m L of Salmonella.After the last treatment,the broilers were fasted for 12 h,weighed,and blood was collected from the heart and executed.The liver,spleen,thymus and bursa were weighed for organ indexes.Paraffin sections and HE staining were applied to observe pathological changes in the liver,jejunum and ileum;enzyme-linked immunosorbent assay(ELISA)was applied to detect changes in intestinal permeability-related indicators and immunoglobulin levels;kits were applied to detect liver function-related indicators;real-time fluorescence quantitative PCR(q PCR)was applied to detect intestinal The m RNA expression levels of antioxidant and inflammation related indexes were detected by q PCR,and the expression and localization of intestinal tight junction proteins were analyzed by immunohistochemistry.The results showed that the broiler chickens in the M-HNa group had indexes closer to those in the CON group,and the damage to the intestine and liver was significantly reduced.Compared with the MOD group,the end weight,mean daily gain and immune organ(spleen,thymus and bursa)indexes of broilers in the M-HNa group were significantly improved(P<0.05);AST,ALT and AKP activities were not significantly increased;intestinal permeability was reduced and the expression level of tight junction proteins was increased(P<0.05);serum inflammatory indicators IL-1β,IL-8 and TNF-αlevels were significantly lower(P<0.05)and IL-10 levels were significantly higher(P<0.05);m RNA expression levels of intestinal inflammatory markers IL-1β,IL-8,TNF-α,NF-κB,TLR4,My D88,NLRP3,Caspase-1 were significantly lower(P<0.05)and m RNA expression of IL-10,IκB levels were significantly increased(P<0.05);serum and intestinal oxidative stress indicators CAT,T-AOC and T-SOD activities were significantly increased(P<0.05)and MDA concentrations were significantly decreased(P<0.05);m RNA expression of intestinal oxidative stress indicators NQO1 and CAT were significantly increased(P<0.05)and m RNA expression of HMOX1 and i NOS(P<0.05).In conclusion,the addition of HNa to the diet could alleviate intestinal damage caused by Salmonella infection in broiler chickens by reducing intestinal inflammation,decreasing intestinal permeability and increasing the expression of intestinal tight junction proteins,with 4 g/kg HNa being more effective than other doses. |
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