Effects of Antimicrobial Peptides Gal-13 on the Growth Performance, Intestinal Microbiota, Digestive Enzyme Activities, Intestinal Morphology, Antioxidative Activities, and Immunity of Broilers

Effect of casein bioactive peptides on performance, nutrient digestibility, enzyme activity and intestinal microbial population in broiler chickens

This experiment was carried out to investigate the effect of bioactive peptides derived from casein on performance, nutrient digestibility, enzyme activity and intestinal microbial population in broiler chickens. In this study, 350 1-day-old male Ross 308 broiler chicks were distributed among 35 pens in a completely randomized design with seven treatments, five replicates and 10 chicks in each replicate. The experimental treatments included: basal diet without any additives (control), basal diet + Avilamycin antibiotic, basal diet + 200, 400, 600, 800 and 1000 mg of peptides per kg of diet. Results showed no significant effects of the experimental treatments on weight gain and feed conversion ratio during the starter period, but there was a significant improvement in weight gain in grower, finisher and whole periods in chicks fed with diet containing 1000 mg/kg peptides (p < 0.05). Adding peptides improved intestinal morphology (in duodenum and ileum) (p < 0.05). Supplementation of casein peptides significantly reduced thiobarbituric acid reactive substances concentration in breast and thigh meat. The activity of amylase, lipase and protease enzymes improved in treatments containing 800 and 1000 mg peptides in comparison to the control treatment. The use of casein-peptides increased intestinal Lactobacillus and decreased Coliform populations.

Effects of dietary supplement of ε-polylysine hydrochloride on laying performance, egg quality, serum parameters, organ index, intestinal morphology, gut microbiota and volatile fatty acids in laying hens

BACKGROUND

ε-polylysine hydrochloride (ε-PLH) is a naturally occurring antimicrobial peptide extensively utilized in the food and medical industries. However, its impact on animal husbandry remains to be further explored. Therefore, the present study aimed to determine the effect of ε-PLH on laying hens' health and laying performance.

RESULTS

Dietary supplementation with ε-PLH to the diet significantly increased average egg weight during weeks 1-8. Meanwhile, compared with the control group, supplementation with ε-PLH decreased the feed egg ratio during weeks 9-12 and egg breakage rate during weeks 9-16 ，whereas it increased eggshell strength during weeks 1-4 and 13-16 . The ε-PLH 0.05% group increased yolk percentage during weeks 5-8 and yolk color during weeks 1-4 . Furthermore, ε-PLH supplementation significantly increased the concentrations of total protein, albumin, globulin and reproductive hormones estradiol, as well as decreased interleukin-1 beta and malondialdehyde in the serum. Compared with the control group, supplementation with 0.05% ε-PLH significantly increased the relative abundance of Cyanobacteria and Gastranaerophilales and decreased the abundance of Desulfovibrio and Streptococcus in the cecum microbiota. In addition, ε-PLH 0.1% supplementation also increased acetic acid content in the cecum.

CONCLUSION

Dietary supplementation with ε-PLH has a positive impact on both productive performance and egg quality in laying hens. Furthermore, ε-PLH can also relieve inflammation by promoting the immunity and reducing oxidative damage during egg production. ε-PLH has been shown to improve intestinal morphology, gut microbial diversity and intestinal health. © 2023 Society of Chemical Industry.

Effects of cyclic antimicrobial lipopeptides from Bacillus subtilis on growth performance, intestinal morphology, and cecal gene expression and microbiota community in broilers

This study investigated the effects of cyclic antimicrobial lipopeptides (CLPs) from Bacillus subtilis on the growth performance, gut morphology, and cecal gene expression and microbiota in broilers; 120 1-day-old unsexed Arbor Acres chicks were randomly divided into four groups, with six replicates in each group and five broilers per cage. These groups were fed a basal diet (C), basal diet plus 10-mg enramycin/kg (E), and basal diet plus 51-mg CLPs/kg (L) or 102-mg CLPs/kg (H). The results indicated that CLP supplementation linearly increased the body weight compared with the C group at 35 days of age. Between 15 and 35 days and 1 and 35 days of age, CLP supplementation linearly increased the average daily gain compared with the C group. The duodenal villus height was significantly increased in the H group compared with the C and E groups. In the cecum, CLP supplementation linearly increased SOD and ZO-1 mRNA expression compared with the C group. β diversity of microbiota indicated distinct clusters between the groups. CLP supplementation linearly increased the abundance of the genus Lactobacillus in the cecal digesta compared with the C group. These results demonstrate that B. subtilis-produced CLPs dose-dependently increase broilers' growth performance, improve their gut morphology, and modulate their gut microbiota.

Compound bioengineering protein improves growth performance and intestinal health in broiler chickens under high-temperature conditions

In recent years, more frequent and prolonged periods of high ambient temperature in summer compromised poultry production worldwide. This study was conducted to investigate the effects of compound bioengineering protein (CBP) on the growth performance and intestinal health of broilers under high ambient temperatures. A total of 400 one-day-old Arbor Acres birds were randomly distributed into five treatment groups: control group (CON) with basal diet, or a basal diet supplemented with CBP 250, 500, 750, and 1,000 mg/kg, respectively. The trial lasted 42 d, all birds were raised at normal ambient temperature for the first 21 d and then subjected to the artificial hyperthermal condition with the temperature at 32 ± 2 °C and relative humidity at 60 ± 5% during 22 to 42 d. Dietary CBP supplementation improved the growth performance and serum antioxidant capacity (total antioxidant capacity and total superoxide dismutase), and decreased serum cortisol, aminotransferase, and alkaline phosphatase of broilers. Dietary CBP inclusion enhanced intestinal barrier function by promoting intestinal morphology and reducing intestinal permeability (diamine oxidase), increased the intestinal antioxidant capacity by elevating glutathione peroxidase activity in the duodenum, reducing malondialdehyde content in the jejunum. Dietary CBP supplementation also alleviated intestinal inflammation by decreasing interleukin (IL)-6 content in the jejunum and ileum, promoting IL-10 levels in the ileum, down-regulating the mRNA abundance of intestinal inflammatory-related genes interferon-gamma (IFN-γ) in the duodenum and up-regulating IL-10 in the jejunum. Additionally, CBP increased the population of total bacteria and Lactobacillus in cecal chyme. Collectively, dietary CBP inclusion exerts beneficial effects on the broilers, which are reflected by enhancing antioxidant capacity, promoting intestinal barrier function, ameliorating intestinal immune response, and regulating intestinal bacteria, thus improving the growth performance of broilers under high-temperature conditions. In general, 750 mg/kg CBP supplementation is more effective.

Surface Display of porcine circovirus type 2 antigen protein cap on the spores of bacillus subtilis 168: An effective mucosal vaccine candidate

The oral mucosal vaccine has great potential in preventing a series of diseases caused by porcine circovirus type 2 (PCV2) infection. This study constructed a recombinant Bacillus subtilis RB with PCV2 Capsid protein (Cap) on its spore surface and cotB as a fusion partner. The immune properties of the recombinant strain were evaluated in a mouse model. IgA in intestinal contents and IgG in serum were detected by enzyme-linked immunosorbent assay (ELISA). The results demonstrated that recombinant spores could activate strong specific mucosal and humoral immune responses. In addition, spores showed good mucosal immune adjuvant function, promoting the proliferation of CD3+, CD4+ and CD8+ T cells and other immune cells. We also found that the relative expression of inflammatory cytokines such as IL-1β, IL-6, IL-10, TNF-α and IFN in the small intestinal mucosa was significantly up-regulated under the stimulation of recombinant bacteriophage. These effects are important for the balance of Th1/Th2-like responses. In summary, our results suggest that recombinant B. subtilis RB as a feed additive provides a new strategy for the development of novel and safe PCV2 mucosal subunit vaccines.

Dietary Antimicrobial Peptides Improve Intestinal Function, Microbial Composition and Oxidative Stress Induced by Aeromonas hydrophila in Pengze Crucian Carp (Carassius auratus var. Pengze)

There is increasing evidence for the potential use of antimicrobial peptides as dietary supplements and antibiotic substitutes. In this study, we analyzed the differential effects of varying levels of antimicrobial peptides on the intestinal function and intestinal microbial and disease resistance of Pengze crucian carp. Approximately 630 experimental fishes were randomized in the control group (G0: 0 mg/kg) and in five groups supplemented with different doses of AMPs (G1: 100 mg/kg, G2: 200 mg/kg, G3: 400 mg/kg, G4: 800 mg/kg, and G5: 1600 mg/kg) and were fed for ten weeks. Three replicates per group of 35 fish were performed. The results showed that AMPs promoted intestinal villus development and increased intestinal muscular thickness (p < 0.05) and goblet cell abundance. The enzymatic activities of all groups supplemented with AMPs were effectively improved. AMP supplementation significantly enhanced the activities of antioxidant enzymes and digestive enzymes in the intestines of G3 animals (p < 0.05). Compared with G0 animals, AMP-supplemented animals regulated the expression of intestinal immune-related genes and exhibited significant differences in the G3 animal group (p < 0.05). The abundance of intestinal Firmicutes and Bacteroidetes increased in the AMP-supplemented groups, but the Firmicutes/Bacteroidetes ratio was lower than that in the G0 group. AMP supplementation also decreased the abundance of Fusobacterium while increasing the proportion of Actinobacteria (p < 0.05). After Aeromonas hydrophila infection, the expression levels of anti-inflammatory factors in the intestinal tract of G3 animals were significantly upregulated, and the level of the proinflammatory factor was decreased (p < 0.05). The intestinal Cetobacterium levels of G3 animals were significantly increased (p < 0.01), while the Proteobacteria levels were decreased, and the intestinal goblet cell proliferation was significantly lower than that of G0 animals (p < 0.05). This indicates that groups supplemented with AMPs have better disease resistance than the G0 group and can rapidly reduce the adverse effects caused by inflammatory response. Taken together, the present results suggest that AMP supplementation can improve intestinal function and intestinal microbial and pathogen resistance in Pengze crucian carp.