Protection Of Astragalus Polysaccharides,Astragalus Total Saponins And Probiotics Complex On Intestine In Broilers Infected With E.coli

The diseases of the avian pathogenic E.coli is mainly occurs in chicken,which brings great economic losses to the poultry industry.Both astragalus active ingredients and probiotics have the functions of enhancing immunity and antioxidant capacity,protecting the intestinal health.In this study,the protective effects of astragalus active ingredients?polysaccharides and total saponins?and probiotics complex?Streptococcus agalactiae,Lactobacillus plantarum and Bacillus subtilis?was evalucated on the intestinal health of broilers infected by pathogenic E.coli.In order to evaluate the protective effect of the mixture comprised of astragalus polysaccharide and total saponins,and the complex composed of Streptococcus agalactiae,Lactobacillus plantarum and Bacillus subtilis on the intestinal tract of broilers infected by E.coli.200 1-day-old broilers were randomly divided into 4 groups,50 broilers per group,fed with basic diet.From 1-day-old to21-day-old,broilers in BG?blank group?,PG?positive control group?and EG?model group?groups were given 0.2 mL/d saline,and broilers in TG?treated group?group were fed with 0.2 mL/d probiotics complex?Streptococcus alactolyticus:Lactobacillus plantarum:Bacillus subtilis=1:1:1,concentrations were 1×10⁹ CFU/mL?and the basic diet with Astragalus polysaccharide?1 g/kg?and total astragalus saponins?10 mg/kg?.In PG group,broilers were fed with the basic diet with 50 mg/kg doxycycline hydrochloric soluble powder daily.At the 21-day-old of broilers,the chickens of TG,PG and EG group were given 0.2 mL E.coli O₇₈8 solution?6×10⁸ CFU/mL?orally.Duodenum and jejunum tissues of broilers in 4 groups were collected on 0 d,1 d,7 d,14 d and 21 d after being challenged.The structure of duodenum and jejunum in broilers were observed,the number of cecal flora,the myeloperoxidase?MPO?activity,antioxidant indicators level,the content of s IgA,IL-1,TNF-?and IL-10 in duodenum and jejunum of broilers were evaluated.The results showed that the structures of duodenum and jejunum were less damaged in TG and PG group compared with EG group,the content of IL-1 and TNF-?and activity of MPO were decreased,content of sIgA and IL-10 were increased in TG and PG group,the amount of Lactobacillus was increased and the number of E.coli was decreased in TG group.In order to assess the protective effect of Streptococcus agalactiae on the intestinal health in broilers infected by E.coli.200 1-day-old white feather broilers were randomly divided into 4 groups,50 chickens per group.From 1^st to 10^th day,broilers were taken 0.2 mL/d saline orally in blank group?BG?and model group?EG?,Streptococcus agalactiae group?FG?was given 0.2 mL/d FGM solution with 1×10⁹ CFU/mL orally,Lactobacillus plantarum group?LG?were given 0.2 mL/d solution with Lactobacillus plantarum 1×10⁹ CFU/mL orally.At the 14-day-old,broilers were challenged by 0.2 mL E.coli O₇₈ solution with 6×10⁸ CFU/mL orally in FG group,LG group and EG group.On 0 day,1^stt day,3^rd day and 7^th day after being challenged by E.coli O₇₈,the structure of duodenum and jejunum in broilers were observed,the number of cecal flora,the myeloperoxidase?MPO?activity,antioxidant indicators level,the content of sIgA,IL-1,TNF-?,IL-10,TLR4 and NF-?B in duodenum and jejunum of broilers were evaluated.The results showed that the structures of duodenum and jejunum were less damaged in FG group and LG group compared with EG group,the content of IL-1 and TNF-?and activity of MPO were decreased,and sIgA and IL-10 content were increased in FG group and LG group,the content of TLR4 and NF-?B were decreased in FG group and LG group,the number of Lactic acid bacteria was increased and the number of E.coli was decreased in FGM group and LG group.In conclusion,when chicken were fed with the mixture astragalus polysaccharide and total astragalus saponins and the complex of Streptococcus agalactiae,Lactobacillus plantarum and Bacillus subtilis,or only fed with Streptococcus agalactiae,intestinal tissue injury and inflammation caused by E.coli could be declined,intestinal immunity could be improved and anti-infection ability could be enhanced.The protection of combination of astragalus active component and probiotics was similar to doxycycline hydrochloride in intestinal injury of broilers.