Effects of Low-Energy Diets Supplemented with Lactobacillus reuteri Postbiotic on Growth Performance and Intestinal Health of Broiler Chickens

This study aims to investigate the effects of low-energy diets (LE) supplemented with Lactobacillus reuteri postbiotics (HSY) on growth performance and intestinal health of broiler chickens. A total of 2400 one-day-old Ross 308 broiler chicks with an average initial body weight of 46.10 +/- 0.04 g were randomly assigned to a 2 & times; 2 factorial arrangement of treatments with 12 pens and 50 broiler chickens/pen for 39 days. Treatments were (1) CTR (basal diet), (2) LE (CTR-70 kcal ME/kg), (3) HSY (CTR + 0.5 kg/t HSY), and (4) LEHSY (LE + 0.5 kg/t HSY). LE increased the feed conversion ratio (FCR) of broilers (p = 0.03) without altering ADG, ADFI, and final BW. Supplementation with HSY significantly reduced the FCR of broilers (p = 0.001). HSY upregulated the activities of amylase and trypsin in jejunal digesta (p < 0.01). Furthermore, LE upregulated the expression of intestinal barrier-related genes such as Mucin-2, Claudin-1 and Occludin, and HSY upregulated the expression of Claudin-1 (p < 0.05). LE upregulated the expression of nutrient transport carriers such as SGLT1 and TRPV6 (p < 0.01), and HSY upregulated the expression of TRPV6 (p < 0.01). LE upregulated the expression of immune-related genes such as MHC-II (p = 0.002), and HSY upregulated the expression of IFN-gamma, IL-10, and TGF-beta (p < 0.05). LE and HSY both downregulated the expression of intestinal lipid metabolism-related genes like ACC, while upregulating the expression of FABP4 (p < 0.05). 16S rRNA sequencing showed that the HSY increased the Chao1 index of the jejunal microbiota and enriched beneficial bacteria such as Lactobacillus salivarius and Lactobacillus avium. LE and HSY both increased the concentrations of propionic and butyrate (p < 0.05). In summary, HSY can improve gut health and mitigate the negative impact of low-energy treatment on broiler growth performance by increasing the content of endogenous enzymes in the jejunum, improving gut microbiota structure, and increasing the content of short-chain fatty acids in the jejunum.