Study On The Control Effect Of Radix Isatidis Ultrafine Powder On Salmonellosis Pullorum In Chicks

Pullorum disease is a poultry disease caused by Salmonella pullorum.It is clinically manifested as sepsis and enteritis.It is popular all over the world,causing serious economic losses to the poultry breeding industry.Although traditional antibiotics are effective in preventing and treating Pullorum disease,long-term use can cause Salmonella pullorum to produce drug-resistant and environmentally resistant strains,posing a potential threat to food safety.Isatis root is a traditional Chinese herbal medicine,which has the functions of clearing heat and detoxifying,cooling blood and relieving pharynx,antibacterial and anti-inflammatory.The chemical components isolated from Radix isatidis,such as alkaloids and polysaccharides,have antiviral,antibacterial and anti-inflammatory,neuroprotective,liver and other pharmacological effects.(1)The content of(R,S)-goitrin in Radix Isatidis micropowder was determined by HPLC under different conditions.The results showed that:Under normal temperature conditions,the isatis root micropowder was soaked in 14 times the mass ratio in distilled water for 0.5 h.The(R,S)-goitrin dissolution rate in the isatis root micropowder was the highest,which was 3.268 mg/g.(2)Microdilution method was used to determine the MIC and MBC of Radix Isatidis micropowder and common powder to Salmonella pullorum;And observe the influence of Isatis indigotica powder on the morphology and structure of Salmonella pullorum by scanning electron microscope and transmission electron microscope.Flow cytometry detected the bactericidal effect of Isatis indigotica powder on Salmonella pullorum.The results showed that:The MIC of Radix isatidis powder against Salmonella pullorum is 0.125 g/mL and the MBC is 0.25 g/mL.The MIC of Radix isatidis powder against Salmonella pullorum is 0.25 g/mL and the MBC is 0.5 g/mL;Scanning electron microscopy and transmission electron microscopy observations show that the isatis root powder can cause the bacteria to overflow and shrink,bend and dent;The cell flow cytometry results showed that the bacterial mortality rate of the blank group was 0.2%,and that of the Isatis indigotica group was 10%.(3)Through experiments,it was determined that the optimal infectious dose of Salmonella pullorum to chickens was 1×10~9 CFU/mL,and the chickens were infected with this dose to establish a pathological model of chicken pullorum.The results of using Radix Isatidis micropowder and ordinary powder to prevent and treat chick pullorum show that:Isatis root powder and common powder have a good control effect on chicks pullorum,can significantly reduce the mortality and morbidity of diseased chickens,and improve the protection rate of diseased chickens.Among them,Isatis root powder prevents middle-dose group(0.25 g/feather)The control effect is the best,and the chicken mortality rate is 14.3%.Subsequently,the testes and ovaries of the infected chicks were taken,and the pathological changes were observed by H.E staining;Take the chicken thymus and bursa of fabric to weigh,and calculate the immune organ index;Elisa determines the activity of aspartate aminotransferase(AST)and alanine aminotransferase(ALT)in the serum of the chickens;Elisa measures the levels of tumor necrosis factor(TNF-?)and interleukin 1(IL-1)in liver tissues of chickens.The results showed that after the prevention and treatment of Isatis indigotica powder and ordinary powder,the tissue structure of the chicken testis was complete,the staining was deep,the spermatogenic cells at all levels were closely arranged,the regularity was strong,the cell morphology was clear,and the follicle structure was complete.Obvious yolk matter,zona pellucida and granular cells,Bursal index and thymus index increased to varying degrees,and serum AST,ALT,TNF-?,and IL-1 decreased.Among them,the effects of Isatis indigotica powder group were more significant than those of Isatis indica powder group.(4)Sequencing the 16s rDNA of the intestinal flora of infected chicks and detecting the effect of Isatis indigotica on the structure and diversity of the intestinal flora of chicks infected with Salmonella pullorum.The results showed that the intestinal flora abundance indexes Ace and Chao of chicks in the Isatis root micronized treatment group were higher than those in the blank group,and the Shannon and Simpson indexes,which reflect the diversity of the intestinal flora,decreased slightly,and the change was not obvious.