Immune Parameters in Chickens Treated with Antibiotics and Probiotics during Early Life

The aim of the study was to compare the effect of the administration of antibiotics or probiotics on chickens in their first week of life, on selected parameters of humoral and cellular immunity, and on the bursa of Fabricius and spleen indices. The experiment was carried out on 90 one-day-old male broilers. The control group received no additive in the drinking water; the group GP received a probiotic providing Enterococcus faecium and Bacillus amyloliquefaciens; and the group GA received 10% enrofloxacin in the drinking water on the first five days of life. Administration of the antibiotic enrofloxacin or a probiotic containing E. faecium and B. amyloliquefaciens strains to chickens in their first week of life exerts pronounced immunomodulatory effects on humoral and cellular defense mechanisms in these birds. The changes in the subpopulations of B and T cells immediately following early administration of enrofloxacin or the probiotic were not observed at the age of 35 days. Early administration of enrofloxacin can pose a risk of suppression of humoral immunity, as indicated by the significant decrease in the total IgY concentration in the plasma of the chickens.

Effects of glucose oxidase and its combination with B. amyloliquefaciens SC06 on intestinal microbiota, immune response and antioxidative capacity in broilers

Glucose oxidase (GOD) is an aerobic dehydrogenase, which catalyses the oxidation of β-D-glucose to gluconic acid and hydrogen peroxide. This study aimed to investigate the effects of dietary glucose oxidase and its combined effects with Bacillus amyloliquefaciens SC06 (BaSC06) on the intestinal microbiota, immune function and antioxidant capacity of broilers. One-day-old male Lingnan yellow-feathered broilers (n = 720) were randomly assigned to four treatment groups: Control group (basal diet), Anti group (basal diet supplemented with 200 mg/kg enramycin), GOD group (basal diet supplemented with 75 U/kg GOD), and combination of GOD and BaSC06 (GB) group (GOD diet (75 U/kg) supplemented with 1 × 10⁸ colony-forming units BaSC06/kg feed), with six replicates per group and 30 birds per replicate. The experiment was conducted over 52 days. The results indicated a significant decrease in α-diversity (Observed species, Chao1, PD_whole_tree and Shannon) with GOD treatment, compared with the control group. GB treatment also significantly decreased the Shannon index of cecal microbiota. GOD treatment significantly decreased the α-diversity, whereas GB treatment significantly increased these indices except for the Chao1 index, compared with the Anti group. Compared with the control group, the relative abundance of Bacteroides in the GOD and GB groups was significantly increased, whereas a decrease in Firmicutes was observed. Compared with the Anti group, GOD treatment significantly increased the relative abundances of Bacteroides and Lactobacillales, while GB treatment significantly increased Lactobacillales and decreased Proteobacteria levels. In addition, GOD treatment significantly decreased interleukin-10 and interferon-γ levels, compared with the control group. In contrast, GB treatment significantly downregulated interferon-γ levels and upregulated secretory immunoglobulin A, transforming growth factor-β and interleukin-2 expression in the jejunal mucosa. GOD treatment significantly decreased transforming growth factor-β and interleukin-10 levels, whereas GB treatment markedly increased interferon-γ expression in the jejunal mucosa compared with the Anti group. Furthermore, GB treatment significantly increased the total antioxidant capability levels and the total superoxide dismutase (T-SOD) and catalase (CAT) activities compared with the control group. Meanwhile, GOD treatment significantly increased glutathione peroxidase (GSH-Px) activity in the jejunal mucosa. Total superoxide dismutase, GSH-Px and CAT activities in the Anti group were higher than in the GOD and GB groups. The malondialdehyde levels in the control group were the highest among all groups. In conclusion, our results indicated that supplementation with GOD alone and its combination with BaSC06 in diet could increase antioxidant capacity, immune function and improve the intestinal microbiota composition of broilers. Combination treatment with GOD with BaSC06 exerted stronger effects than GOD treatment only.

Effects of Dietary Tributyrin on Growth Performance, Biochemical Indices, and Intestinal Microbiota of Yellow-Feathered Broilers

This study aimed to evaluate the effects of tributyrin on growth performance, biochemical indices and intestinal microbiota of yellow-feathered broilers. 360 one-day-old chicks were randomly allocated to three treatments with six replicates of 20 chicks each, including a normal control group (NC), an antibiotic group (PC), and a tributyrin (250 mg/kg) group (TB) for 63 days. The results showed that compared with the control, the feed conversion ratio (FCR) in the TB group decreased during the d22 to d42 (p < 0.05) and overall, the final weight and FCR of broilers tended to increase and decrease, respectively. Moreover, the TB group showed the highest creatine concentrations at the entire period (p < 0.05). TB treatment increased the Bacteroidetes relative abundance and decreased Firmicutes. Principal coordinates analysis yielded clear clustering of the three groups. Linear discriminant analysis effect size analysis found seven differentially abundant taxa in the TB group, including several members of Bacteroidedetes. The relative abundance of Eisenbergiella, Phascolarctobacterium, Megasphaera and Intestinimonas increased in tributyrin-treated broilers. Spearman correlation analysis identified a correlation between Eisenbergiella abundance and overall feed efficiency. These results demonstrated that tributyrin could improve the growth performance by modulating blood biochemical indices and the cecal microflora composition of broilers.

Impact of Dietary or Drinking Water Ruminococcus sp. Supplementation and/or Heat Stress on Growth, Histopathology, and Bursal Gene Expression of Broilers

This research was conducted to evaluate the impact of dietary or drinking water Ruminococcus sp. supplementation and/or heat stress (HS) on the growth, serum biochemistry, tissue antioxidant, phagocytic assay, histopathology, and bursa gene expression of broilers. Day-old broiler chicks were allotted into six groups according to HS and/or Ruminococcus with or without enzyme supplementation. The first group was the control one, with a formulated diet and normal environmental temperature but without any supplement. The second group fed on Ruminococcus-supplemented diet (1 kg/kg diet). The third group fed on a formulated diet without supplement, and Ruminococcus and digestive enzymes were given in drinking water (0.1 ml/L). The fourth one was the heat stress group, with a normal formulated diet. The fifth and the sixth groups served as second and third groups, respectively, but with heat stress. The results of this experiment indicated that thermal temperature negatively affected the parameters of growth performance, serum biochemical, tissue antioxidants, and phagocytic assay. Moreover, heat stress led to pathological lesions in the internal organs and affected the expression of some genes related to heat stress, including proapoptotic genes such as caspase8 and bax, inflammatory genes such as NF-κβ1, and heat shock protein such as HSP 70 in the bursal tissue. These bad effects and abnormalities were mitigated by Ruminococcus alone or with enzyme supplementation, which improved all the above-mentioned parameters.

Preventive antimicrobial action and tissue architecture ameliorations of Bacillus subtilis in challenged broilers

Background and Aim:

Probiotics improve intestinal balance through bacterial antagonism and competitive exclusion. This study aimed to investigate the in vitro antimicrobial activity, as well as the in vivo preventive, immunological, productive, and histopathological modifications produced by probiotic Bacillus subtilis.

Materials and Methods:

The in vitro antimicrobial activities of B. subtilis (5×10⁶ CFU/g; 0.5, 1.0*, 1.5, and 2.0 g/L) were tested against Escherichia coli O157: H7, Salmonella Typhimurium, Candida albicans, and Trichophyton mentagrophytes after exposure times of 0.25, 0.5, 1, and 2 h using minimal inhibitory concentration procedures. A total of 320 1-day-old female Ross broiler chickens were divided into five groups. Four out of the five groups were supplemented with 0.5, 1.0*, 1.5, and 2.0 g/L probiotic B. subtilis from the age of 1 day old. Supplemented 14-day-old broiler chickens were challenged with only E. coli O157: H7 (4.5×10¹² CFU/mL) and S. Typhimurium (1.2×10⁷ CFU/mL). A total of 2461 samples (256 microbial-probiotic mixtures, 315 sera, 315 duodenal swabs, and 1575 organs) were collected.

Results:

The in vitro results revealed highly significant (p<0.001) killing rates at all-time points in 2.0 g/L B. subtilis: 99.9%, 90.0%, 95.6%, and 98.8% against E. coli, S. Typhimurium, C. albicans, and T. mentagrophytes, respectively. Broilers supplemented with 1.5 and 2.0 g/L B. subtilis revealed highly significant increases (p<0.01) in body weights, weight gains, carcass weights, edible organs’ weights, immune organs’ weights, biochemical profile, and immunoglobulin concentrations, as well as highly significant declines (p<0.01) in total bacterial, Enterobacteriaceae, and Salmonella counts. Histopathological photomicrographs revealed pronounced improvements and near-normal pictures of the livers and hearts of broilers with lymphoid hyperplasia in the bursa of Fabricius, thymus, and spleen after supplementation with 2.0 g/L B. subtilis.

Conclusion:

The studies revealed that 1.5-2.0 g of probiotic B. subtilis at a concentration of 5×10⁶ CFU/g/L water was able to improve performance, enhance immunity, and tissue architecture, and produce direct antimicrobial actions.

Oxidative and Epigenetic Changes and Gut Permeability Response in Early-Treated Chickens with Antibiotic or Probiotic

The aim of this study was to compare the effect of the use of enrofloxacin and a probiotic containing Enterococcus faecium and Bacillus amyloliquefaciens strains in the first week of life of chickens on oxidative and epigenetic changes in molecules and intestinal integrity. The three treatments were as follows: the control group received no additive in the drinking water (GC); the second group (GP) received a probiotic preparation in the drinking water during the first five days of life, providing E. faecium strain 4a1713 at 1.0 × 107 CFU/L water and B. amyloliquefaciens 4b1822 at 1.0 × 107 CFU/L water, the third group (GA) received an antibiotic (enrofloxacin 0.5 mL/L water) in the drinking water during the first five days of life. The use of both enrofloxacin and a probiotic containing E. faecium and B. amyloliquefaciens strains in chickens' first week of life improved intestinal integrity and reduced inflammation and oxidative and epigenetic changes in the small intestine. This effect was evident both at 6 days of age and at the end of the rearing period.