This study was carried out to investigate the effect of heat-inactivated compound probiotics on growth performance, plasma biochemical indices, and gut microbiota composition and functions in yellow-feathered broilers. A total of 360 1-day-old broilers were randomly divided into 3 groups, including a basal diet as negative control group (PC), basal diet plus antibiotics with 250 mg/kg calcium oxytetracycline and 200 mg/kg Nosiheptide as positive control (PC), and basal diet plus 500 mg/kg compound probiotics consisting of heat-inactivated Bacillus subtilis and Lactobacillus acidophilus BFI (BFI). Each group had 6 replicates of 20 chickens. On d 21, 42, and 63, one chick from each replicate was selected for blood collection and cecal sampling. Compared to the NC group, dietary supplementation with heat-inactivated compound probiotics increased the feed efficiency during d 1–63 (P < 0.05). The plasma cholesterol content at 42 d and creatinine content at 63 d were decreased by dietary supplementation with heat-inactivated compound probiotics (P < 0.05). The dominant phyla in broiler cecal microbiota were Bacteroidetes, Firmicutes, and Proteobacteria, while the dominant genera were Bacteroides, Ruminococcaceae, and Phascolarctobacterium. The β-diversity index of cecal microbiota in BFI group was increased at d 42 (P < 0.01) and d 63 (P < 0.05). Dietary heat-inactivated compound probiotics increased the relative abundances of Barnesiellaceae (family), Barnesiella (genus), and Lactobacillus aviarius (species) at d 21, and reduced the relative abundances of genera Lachnoclostridium and Peptococcus at d 42, and unidentified Lachnospiraceae and Lachnoclostridium at d 63. The functional prediction of microbiota revealed that supplementation with heat-inactivated compound probiotics enriched the pathways related to methane metabolism, transcription machinery, purine metabolism and protein export. The Spearman's correlation analysis identified a significant correlation between cecal microbiota composition and overall feed efficiency and plasma metabolites. Collectively, dietary heat-inactivated compound probiotics with Bacillus subtilis and Lactobacillus acidophilus BFI enhanced feed efficiency, and decreased plasma cholesterol and creatinine contents, which might be associated with the modulation of community composition, diversity and functions of cecal microbiota in yellow-feathered broilers. These results indicated the potential of heat-inactivated probiotics used as alternatives to antibiotics for improvement of broiler health and productivity.

This study investigated the effect of berberine (BBR) on growth performance and composition and function of cecal microbiota in yellow-feathered broilers. A total of 360 1-day-old female broilers were assigned to 3 dietary treatments, each with 6 replicates of 20 birds. The dietary treatments consisted of a basal diet as negative control (NC), basal plus 200 mg/kg oxytetracycline calcium and 250 mg/kg nasiheptide as an antibiotic positive control (PC), and basal plus 250 mg/kg BBR. On day 21, 42, and 63, one chicken from each replicate was randomly selected for blood collection and cecal sampling. The 16S rRNA sequencing technology was used to analyze the community composition and function of cecal microbiota. Dietary supplementation with antibiotics or BBR increased the final body weight (BW) at day 63 and the average daily gain (ADG) during 1 to 21 d compared with the NC (P < 0.05). Supplementation with BBR improved the average daily feed intake (ADFI) at 22 to 42 d, 43 to 63 d, and 1 to 63 d (P < 0.05). Feed efficiency, indicated by feed to gain ratio (F/G), increased with PC during day 1 to 21 compared with NC (P < 0.05). The plasma concentrations of total protein at 42 d and uric acid at 21 d were increased, whereas creatine concentration at 63 d was decreased by BBR treatment (P < 0.05). The Chao 1 and Shannon index representing microbial α-diversity was reduced by BBR treatment (P < 0.05). The abundances of phylum Firmicutes and genera Lachnospiraceae, Lachnoclostridium, Clostridiales, and Intestinimonas were decreased, whereas the abundances of phylum Bacteroidetes and genus Bacteroides were increased with BBR treatment. Functional prediction of microbiota revealed that BBR treatment enriched pathways related to metabolism, organismal systems, and genetic information processing, especially DNA replication. The abundance of phylum Bacteroidetes, and genera Bacteroides and Lactobacillus in cecal contents were positively correlated with broiler growth performance. These results demonstrated dietary BBR supplementation improved the growth performance of yellow-feathered broilers, and was closely related to the significant changes in cecal microbiota composition.

Resveratrol (RES) displays strong antioxidant and anti-inflammatory properties in protecting the animals from various stressors and inflammatory injuries, but its interrelationship with the gut microbiota remained largely unclear. This study was carried out to investigate the effects of dietary RES supplementation on growth performance, antioxidant capacity, intestinal immunity and gut microbiota in yellow-feathered broilers challenged by lipopolysaccharide (LPS). A total of 240 yellow-feathered broilers were randomly assigned to four treatment groups in a 2 × 2 factorial design. The broilers were fed with the control diet or control diet supplemented with 400 mg/kg RES, followed by challenge with LPS or the same amount of saline. Dietary RES supplementation significantly alleviated the decreases in the final body weight (BW), average daily gain (ADG), and ADFI induced by LPS (P < 0.05). LPS challenge significantly increased plasma concentrations of triglyceride, high-density lipoprotein cholesterol (HDL-C), aspartate aminotransferase (AST), and cortisol levels, but decreased triiodothyronine (T3) and insulin levels (P < 0.05). Dietary supplementation with RES significantly reversed the elevated creatinine concentrations and the decreased concentrations of T3 and insulin caused by LPS (P < 0.05). Moreover, dietary RES supplementation significantly increased plasma total antioxidant capacity (T-AOC) and catalase (CAT) activities and superoxide dismutase (SOD) and T-AOC activities in jejunal mucosa and reduced malondialdehyde (MDA) concentration in the plasma (P < 0.05). The reduction in the villus height to crypt depth ratio in duodenum, jejunum and ileum and the shortening of villus height in jejunum and ileum caused by LPS were also alleviated by RES treatment (P < 0.05). Furthermore, the increased concentrations of intestinal tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β caused by LPS were significantly decreased by RES treatment (P < 0.05). Dietary RES treatment increased the mRNA expression of claudin-1, claudin-5, occludin, and zonula occludens-1 (ZO-1), and decreased mRNA expression of IL-1β, IL-8, IL-17, and TNF-α after LPS challenge (P < 0.05). Dietary RES treatments significantly decreased the dominance of cecal microbiota, and increased the Pieiou-e and Simpson index. Moreover, dietary RES supplementation increased relative abundance of UCG_ 009, Erysipelotrichaceae, Christensenellaceae_R-7_group, Anaerotruncus, RF39, and Ruminococcus while decreasing the abundance of Alistipes at genus level. Spearman correlation analysis revealed that the microbes at the order and genus levels significantly correlated with indicators of growth performance, antioxidant capacity, and intestinal health. Collectively, dietary supplementation with 400 mg/kg RES could improve growth performance and antioxidant capacity, and modulate intestinal immunity in yellow-feathered broilers challenged by LPS at early stage, which might be closely associated with the regulation of gut microbiota community composition.

This study aimed to investigate the protective effects of Lactobacillus plantarum 16 (Lac16) and Paenibacillus polymyxa 10 (BSC10) against Clostridium perfringens (Cp) infection in broilers. A total of 720 one-day-old chicks were randomly divided into four groups. The control and Cp group were only fed a basal diet, while the two treatment groups received basal diets supplemented with Lac16 (1 × 10⁸ cfu·kg⁻¹) and BSC10 (1 × 10⁸ cfu·kg⁻¹) for 21 days, respectively. On day 1 and days 14 to 20, birds except those in the control group were challenged with 1 × 10⁸ cfu C. perfringens type A strain once a day. The results showed that both Lac16 and BSC10 could ameliorate intestinal structure damage caused by C. perfringens infection. C. perfringens infection induced apoptosis by increasing the expression of Bax and p53 and decreasing Bcl-2 expression and inflammation evidence by higher levels of IFN-γ, IL-6, IL-1β, iNOS, and IL-10 in the ileum mucosa, and NO production in jejunal mucosa, which was reversed by Lac16 and BSC10 treatment except for IL-1β (P &lt; 0.05). Besides, the two probiotics restored the intestinal microbiota imbalance induced by C. perfringens infection, characterized by the reduced Firmicutes and Proteobacteria and the increased Bacteroidetes at the phyla level and decreased Bacteroides fragilis and Gallibacterium anatis at the genus level. The two probiotics also reversed metabolic pathways of the microbiota in C. perfringens-infected broilers, including B-vitamin biosynthesis, peptidoglycan biosynthesis, and pyruvate fermentation to acetate and lactate II pathway. In conclusion, Lac16 and BSC10 can effectively protect broilers against C. perfringens infection through improved composition and metabolic pathways of the intestinal microbiota, intestinal structure, inflammation, and anti-apoptosis.

Clostridium perfringens is an important zoonotic pathogen associated with food contamination and poisoning, gas gangrene, necrotizing enterocolitis or necrotic enteritis in humans and animals. Dysbacteriosis is supposedly associated with the development of C. perfringens infection induced necrotic enteritis, but the detailed relationship between intestinal health, microbiome, and C. perfringens infection-induced necrotic enteritis remains poorly understood. This research investigated the effect of probiotics on the growth performance and intestinal health of broilers, and the involved roles of intestinal microbiota and microbial metabolic functions under C. perfringens infection. Results showed that subclinical necrotic enteritis was successfully induced as evidenced by the significant lower body weight (BW), suppressed feed conversion ratio (FCR), decreased ileal villus height and mucosal barrier function, and increased ileal histopathological score and bursal weight index. Lactobacillus plantarum or Paenibacillus polymyxa significantly attenuated C. perfringens-induced compromise of growth performance (BW, FCR) and ileal mucosa damage as illustrated by the increased ileal villus height and villus/crypt ratio, the decreased ileal histopathological score and the enhanced ileal mucosal barrier function. L. plantarum also significantly alleviated C. perfringens-induced enlarged bursa of fabricius and the decreased levels of ileal total SCFAs, acetate, lactate, and butyrate. Furthermore, dietary L. plantarum improved C. perfringens infection-induced intestinal dysbiosis as evidenced by significantly enriched short-chain fatty acids-producing bacteria (Lachnospiraceae, Ruminococcaceae, Oscillospira, Faecalibacterium, Blautia), reduced drug-resistant bacteria (Bacteroides, Alistipes) and enteric pathogens (Escherichia coli, Bacteroides fragilis) and bacterial metabolic dysfunctions as illustrated by significantly increased bacterial fatty acid biosynthesis, decreased bacterial lipopolysaccharide biosynthesis, and antibiotic biosynthesis (streptomycin and vancomycin). Additionally, the BW and intestinal SCFAs were the principal factors affecting the bacterial communities and microbial metabolic functions. The above findings indicate that dietary with L. plantarum attenuates C. perfringens-induced compromise of growth performance and intestinal dysbiosis by increasing SCFAs and improving intestinal health in broilers.

Hypoxanthine (Hx), an intermediate metabolite of the purine metabolism pathway which is dramatically increased in blood and skeletal muscle during muscle contraction and metabolism, is characterized as a marker of exercise exhaustion. However, the physiological effects of Hx on skeletal muscle remain unknown. Herein, we demonstrate that chronic treatment with Hx through dietary supplementation resulted in skeletal muscle fatigue and impaired the exercise performance of mice without affecting their growth and skeletal muscle development. Hx increased the uncoupling protein 2 (UCP2) expression in the skeletal muscle, which led to decreased energy substrate storage and enhanced glycolysis. These effects could also be verified in acute treatment with Hx through intraperitoneal injection. In addition, muscular specifically knockout of UCP2 through intra-muscle tissue injection of adenovirus-associated virus reversed the effects of Hx. In conclusion, we identified a novel role of Hx in the skeletal muscular fatigue mediated by UCP2-dependent mitochondrial uncoupling. This finding may shed light on the pathological mechanism of clinical muscle dysfunctions due to abnormal metabolism, such as muscle fatigue and weakness.