Changed cecal microbiota involved in growth depression of broiler chickens induced by immune stress.

A previous study identified genes and metabolites associated with amino acid metabolism, glycerophospholipid metabolism, and inflammatory response in the liver of broilers with immune stress. The present research was designed to investigate the effect of immune stress on the cecal microbiome in broilers. In addition, the correlation between altered microbiota and liver gene expression, the correlation between altered microbiota and serum metabolites were compared using the Spearman correlation coefficients. Eighty broiler chicks were randomly assigned to 2 groups with 4 replicate pens per group and 10 birds per pen. The model broilers were intraperitoneally injected of 250 µg/kg LPS at 12, 14, 33, and 35 d of age to induce immunological stress. Cecal contents were taken after the experiment and kept at -80°C for 16S rDNA gene sequencing. Then the Pearson's correlation between gut microbiome and liver transcriptome, between gut microbiome and serum metabolites were calculated using R software. The results showed that immune stress significantly changed microbiota composition at different taxonomic levels. KEGG pathways analysis suggested that these gut microbiota were mainly involved in biosynthesis of ansamycins, glycan degradation, D-glutamine and D-glutamate metabolism, valine, leucine, and isoleucine biosynthesis and biosynthesis of vancomycin group antibiotics. Moreover, immune stress increased the activities of metabolism of cofactors and vitamins, as well as decreased the ability of energy metabolism and digestive system. Pearson's correlation analysis identified several bacteria were positively correlated with the gene expression while a few of bacteria were negatively correlated with the gene expression. The results identified potential microbiota involvement in growth depression mediated by immune stress and provided strategies such as supplement of probiotic for alleviating immune stress in broiler chickens.

Effect of yeast culture supplementation on blood characteristics, body development, intestinal morphology, and enzyme activities in geese.

The objective of this experiment is to evaluate the effects of yeast culture (YC) supplementation on blood characteristics, body size, carcass characteristics, organ weights, intestinal morphology, and enzyme activities. Five groups of geese were randomly assigned to five dietary treatments: the basal diet (control) and basal diets plus 0.5%, 1.0%, 2.0%, or 4.0% YC. Compared with the controls, YC supplementation at 0.5% and 1.0% increased the serum total protein (TP), albumin (ALB), and globulin (GLO) and decreased the uric acid and creatine kinase (CK) contents (p < 0.05). YC supplementation at 2.0% and 4.0% increased the CK, growth hormone, catalase and glutathione reductase contents, and relative proventriculus weights, and decreased the TP, ALB, and GLO contents, relative liver, gizzard, jejunum, ileum, and thymus weights (p < 0.05). YC supplementation at 2.0% improved fossil bone length, breast muscle percentage, jejunal villus height, ileal and jejunal villus height/crypt depth ratios, pepsin, lipase, amylase and pancreatic trypsin activities, and decreased abdominal fat percentage (p < 0.05). Furthermore, YC inclusion increased the body slope length (linear, p = 0.002; quadratic, p = 0.02), breast width (quadratic, p = 0.02), ileal (linear, p = 0.04; quadratic, p = 0.01) and duodenal villus height (cubic, p = 0.04), and decreased the relative gizzard (quadratic, p = 0.04) and thymus (linear, p = 0.002; quadratic, p = 0.02; cubic, p = 0.02) weights, liver (linear, p = 0.002; quadratic, p = 0.02), and serum (linear, p = 0.006; quadratic, p = 0.03) malondialdehyde contents, and jejunal crypt depth (quadratic, p = 0.03). The findings indicated that the YC supplementation had a positive effect on the growth and development of geese, with 2% YC being the most effective.