Effects of dietary supplementation with lysozyme on the structure and function of the cecal microbiota in broiler chickens

Abstract

Lysozyme is known to eliminate intestinal pathogens in poultry and improve their growth performance. However, whether it can replace antibiotic growth promoters without the associated risk of the emergence of antibiotic-resistant bacterial strains is not known, and the effects of lysozyme supplementation on the composition, biodiversity, and function of the chicken gut microbiota remain unclear. Here, we used the 16S rRNA gene and ITS fragment Illumina sequencing combined with transcriptomic analysis to address this issue. A total of 400 1-d-old Di Gao chicks were allocated randomly to five groups, each consisting of four replicates (20 birds/group). The chicks were fed a starter (1–21 d) and a grower (22–42 d) diet supplemented with 0 (control), 40 (LYS40), 100 (LYS100), or 200 ppm (LYS200) lysozyme, or 400 ppm flavomycin as an antibiotic control for 6 weeks. Lysozyme administration did not contribute significantly ( P > 0.05) to the growth of the broiler chickens. No significant ( P > 0.05) differences in the diversity and composition of the bacterial and fungal communities in the cecal microbiota of chickens in the different diet groups were found. However, lysozyme supplementation led to a significant ( P < 0.05) enrichment of genes involved in the synthesis/degradation of bacterial outer membranes and cell walls, cross-cell substrate transport, and carbohydrate metabolic processes, thus possibly promoting the cecal microbiota carbon and energy metabolism. Bacteroides contributed 31.9% of glycoside hydrolase genes (17,681–24,590), 26.1% of polysaccharide lyase genes (479–675), 20.7% of carbohydrate esterase genes (3,509–4,101), 8.8% of auxiliary activity genes (705–1,000), 16.2% of glycosyltransferase genes (5,301–6,844), and 13.9% of carbohydrate-binding module genes (8838–15,172) identified in the cecal samples. Thus, they were the main players in the breakdown of non-starch polysaccharides in the cecum, although Parabacteroides , Alistipes , Prevotella , Clostridium , Blastocystis , Barnesiella , Blautia , Faecalibacterium , Subdoligranulum , Megamonas , Eubacterium , Ruminococcus , Paenibacillus , Bifidobacterium , Akkermansia , and other bacteria also participated.

Effects of Dietary Ferulic Acid on the Intestinal Microbiota and the Associated Changes on the Growth Performance, Serum Cytokine Profile, and Intestinal Morphology in Ducks

“…The possible explanation to the inconsistencies might be the constructional and functional differences of the GIT between birds and mammals, as well as the sensitivities of the microbiome to FA in the diverse animal species. Previous papers illustrated that cecal bacterial microbiome of birds were usually dominated by members of the phyla Bacteroidetes and Firmicutes , followed by lower abundance of Proteobacteria , Actinobacteria and others ( Costa et al, 2017 ; She et al, 2018 ; Xia et al, 2019 ). It was consistence with the cecal microbial construction in the present study.…”

Spatial heterogeneity of the shorebird gastrointestinal microbiome

“…Genera mentioned were significantly higher than compared to their two adjacent sections. Significance was assigned if adjusted p-values < 0.01. involved in the degradation of non-starch polysaccharides and monosaccharides [62,63]; a function that could translate to shorebird caeca.…”

Intestinal Microbes of Hooded Cranes (Grus monacha) Wintering in Three Lakes of the Middle and Lower Yangtze River Floodplain

“…The higher diversity of intestinal bacteria might be beneficial for the Hooded Cranes at Shengjin Lake to obtain nutrients effectively from indigestible and nutrient-limited food [ 53 ]. Indeed, our study showed that the Hooded Cranes at Shengjin Lake harbored more abundant genus, such as Bacillus, Clostridium and Paenibacillus which can metabolize cellulose and improve the degradation of non-starch polysaccharides ( Figure 5 ) [ 54 , 55 ]. In addition, we found that the genera Anaerorhabdus and Ewingella were more abundant in the gut of the Hooded Cranes at Caizi Lake, which might be detrimental for the host and increase the risk of host infection, respectively ( Figure 5 ) [ 56 , 57 ].…”