Study On Probiotic Effects Of Lactobacillus Reuteri SL001 On Chickens

Probiotics play an important role in maintaining intestinal microecological balance and protecting human health.Unlike antibiotics,probiotics cannot induce the host to produce drug-resistant bacteria or drug residues and are environmentally friendly.However,the application of probiotics also has defects,and the interaction mechanism between probiotics and the host is still not very clear at present,so its targeted application in animal husbandry production is limited.To clarify the interaction mechanism between probiotics and the host is one of the hotspots of current research.In this study,L.reuteri SL001 was used as feed additive for AA white broilers and Roman powder laying hens in late laying period.To evaluate the probiotic effects of L.reuteri SL001 on chickens.The main results are as follows:1.L.reuteri SL001 can improve the growth performance and slaughter performance of broilersThe experiment was randomly divided into three treatment groups(control group,antibiotic group and SL001 group)for 42 days.The results showed as follows:(1)Compared to the control group,supplementation of SL001 in the diet resulted in significant increases in final weight,average daily gain,and average daily feed intake of broilers.Compared with antibiotic group,SL001 group significantly increased body weight and average daily gain of broilers,and significantly decreased average daily feed consumption and feed/gain of broilers.(2)In the middle feeding period,SL001 group significantly increased slaughter rate,eviscerated rate and half-eviscerated rate of broilers compared with the control group;At the end of feeding,SL001 significantly increased the evisceration rate compared to the control group.2.L.reuteri SL001 can enhance antioxidant capacity,improve immune performance and affect serum biochemical indexes of broilersThe results showed as follows:(1)Effects of L.reuteri SL001 on serum immune indices of broilers.At 21 days of age,After SL001 and antibiotic treatment,the levels of interleukin 6(IL-6),interleukin 4(IL-4),and tumor necrosis factor α(TNF-α)in serum of broilers were significantly decreased;Besides,interleukin 10(IL-10),transforming growth factor β(TGF-β),immunoglobulin M(Ig M),immunoglobulin A(Ig A),immunoglobulin G(Ig G),immunoglobulin E(Ig E),secreted immunoglobulin A(s Ig A),and complement protein 4(C4)were significantly increased in SL001 and antibiotic supplementation group.Moreover,at 42 days of age,the differences of immune indexes between SL001 group and antibiotic group and control group showed the same trend as at 21 days of age.(2)Effects of L.reuteri SL001 on serum antioxidant related indexes of broilers.At21 days of age,the activities of antioxidant enzymes including total antioxidant capacity(T-AOC),catalase(CAT),reduced glutathione(GSH)and superoxide dismutase(SOD)in broilers with SL001 and antibiotic supplemental diets were significantly higher than the control group.The serum malondialdehyde(MDA)concentration of broilers feeding with SL001 and antibiotic diets were significantly lower than the control diet.At 42 days of age,the trend of serum antioxidant indexes in SL001 group and antibiotic group was the same as that at 21 days of age.(3)Effects of L.reuteri SL001 on routine serum biochemical indices of broilers.In the middle feeding period,SL001 and antibiotic supplementation in the feed led to significantly higher levels of albumin(ALB),total protein(TP),alkaline phosphatase(AKP),lipase(LPS)and pepsin(PEP),but lower levels of creatinine(Cr)and uric acid(UA)compared to the control group.Meanwhile,SL001 supplementation also significantly increased the content of amylase(AMS)in serum.At the end of feeding,the changes trend of serum biochemical indexes was similar to those in the middle feeding period.In addition,supplementation with SL001 and antibiotics significantly decreased serum total cholesterol(TCHO),triglyceride(TG),very low density lipoprotein cholesterol(VLDL-C),and low density lipoprotein cholesterol(LDL-C),while significantly increased high density lipoprotein cholesterol(HDL-C)in both middle and late feeding stages.(4)Effects of L.reuteri SL001 on multiple gene expression in liver and jejunum of broilers.In liver,compared with control group and antibiotic group,SL001 supplementation could significantly increase the expression levels of SOD,CAT,GPx and GHR genes.In the liver,the expression level of ACAT2 gene in SL001 group was significantly increased compared with that in antibiotic group.In jejunum,SL001 supplementation significantly reduced the expression of HMGCR gene.3.L.reuteri SL001 can promote intestinal development and optimize intestinal microbiota of broilersThe results were as follows:(1)Diets with SL001 and antibiotic supplementation significantly increased the villus height and the ratio of villus height to crypt depth in the ileum of broilers.Besides,a lower crypt depth and a higher ratio of villus height to crypt depth in the jejunum were observed in the broilers feeding with the SL001 and antibiotic diet.(2)Feeding SL001 significantly increased the relative abundance of Actinobacteria.At the genus level,compared with the control group,SL001 group significantly increased the relative classification of Ruminococcaceae and Clostridiales.The relative abundance of Faecalibacterium and Parabacteroides was significantly decreased.4.L.reuteri SL001 can improve the laying rate and egg quality,improve serum biochemical indices and intestinal morphology of roman powder laying hensThe experiment was randomly divided into three groups: control group,high-dose group(SL001 H)and low-dose group(SL001 L).The experiment lasted for 12 weeks.The results were as follows:(1)The average egg weight,laying rate and feed consumption of eggs in both high-dose and low-dose groups were significantly increased.(2)The high dose group could significantly enhance the eggshell hardness of eggs.At 57 to 62 and 57 to 68 weeks of age,both SL001 treatment groups significantly increased eggshell thickness.(3)Both SL001 treatment groups could significantly increase the pancreatic index and spleen index of laying hens.(4)SL001 H and SL001 L groups could significantly reduce the content of IL-6 in serum and TG in yolk of laying hens.(5)The crypt depth of ileum in SL001 H group was significantly decreased.