Effects And Mechanism Of Glutamine In Alleviating Intestinal Inflammatory Injury In Piglets

Glutamine is the main energy substance of intestinal cells,which can maintain intestinal health and normal physiological function.The purpose of this paper is to explore the effects and mechanism of glutamine in alleviating intestinal inflammatory injury in piglets,which will provide a scientific basis for applying of glutamine in alleviating intestinal injury and improving the economic benefits of pig healthy breeding.In the experiment,32 piglets weighed 16 ± 0.58 kg were randomly divided into four treatments according to their initial body weight.The experiment used 2 × 2 experimental design.The control group were fed with the basic diet(CON);the other groups were fed with the basic diet supplemented with 0.1% bisphenol A(BPA)(BPA),0.1% BPA and 1% Gln(BPA + Gln)and 1% Gln(Gln),respectively.The trial period was 42 days.The results showed that:(1)Compared with the CON group,the piglet final weight,average daily weight gain,average daily feed intake and the apparent nutrient digestibility were significantly decreased in BPA group(P < 0.05).However,levels of serum lactate dehydrogenase,total protein and urea nitrogen and pro-inflammatory factors interleukin-1β(IL-1β),interleukin-6(IL-6)and tumor necrosis factor-α(TNF-α)were significantly increased(P < 0.05),but the level of anti-inflammatory factor interleukin-10(IL-10)were decreased(P< 0.05).Compared with the BPA group,final weight,average daily feed intake,crude fat and crude gray digestibility were significantly higher in BPA + Gln group(P < 0.05).Nevertheless,levels of serum IL-1β,IL-6,and TNF-α were significantly decreased,but the level of IL-10 was significantly increased(P < 0.05).(2)Compared with the CON group,the colonic tissue mucosa was severely damaged,with epithelial detachment,apical rupture of colonic glands,less goblet cells,and lower Trefoil factor(TFF3)expression in BPA group(P < 0.05).But the m RNA expressions of pro-inflammatory factors Toll like receptor 4(TLR4),Myeloid differentiation factor 88(My D88),Nuclear factor kappa-b(NF-κB),Tumor necrosis factor-α(TNF-α),Interleukin-1β(IL-1β),and Human Interferon-γ(IFN-γ)were significantly increased(P < 0.05).In addition,immunoreactivity of NF-κB was enhanced,and NF-κB and TLR4 protein expression was significantly higher in BPA group(P < 0.05).Compared with the BPA group,the BPA + Gln group had integrated colonic mucosal epithelium and apical colonic glands,more goblet cells,and higher TFF3 expression(P < 0.05).However,TLR4,My D88,TNF-α,NF-κB and IL-1βm RNA expression were significantly decreased(P < 0.05),and NF-κB immunoreactivity were diminished in BPA + Gln colon.But NF-κB and TLR4 protein expression were significantly downregulated(P < 0.05).(3)Compared with the CON group,the cecum mucosa of the BPA group was severely damaged,with ruptured epithelial cells,less goblet cells and lower TFF3 expression,and lower acetate and total volatile fatty acid content in cecum chyme(P < 0.05).In addition,the abundance of Firmicutes and Agathobacter was significantly decreased(P < 0.05),while the abundance of Acidobacteriota,Actinobacteria,Actinobacteriota and Roseburia were significantly increased in BPA group(P < 0.05).Compared with the BPA group,the cecum mucosal epithelium and apical part of the colonic glands was integrated,and the number of goblet cells,expression of TFF3 and contents of cecum chyme acetate and total volatile fatty acid were significantly increased in BPA + Gln group(P < 0.05).Moreover,Gln supplemented in BPA diet significantly increased the abundance of Firmicutes,Clostridium＿sensu＿stricto＿1 and Agathobacter was significantly higher(P < 0.05),but decreased the abundance of Actinobacteriota(P < 0.05).The correlation analysis showed that the total volatile fatty acids and butyrate were positively correlated with Prevotella＿9 and Prevotellaceae＿NK3B31＿group,and the total volatile fatty acids were also positively associated with Roseburia.In conclusion,Gln improved piglet the production performance,repair the intestinal morphological structure,inhibit the TLR4/NF-κB pathway,and then downregulate the production and expression of pro-inflammatory factors such as TLR4,My D88,TNF-α,NF-κB and IL-1β,and regulate the cecal microbial flora structure to some extent,thus alleviate intestinal inflammatory injury and maintain intestinal health.