Explore the vast range of titles available.

Background The excessive use of antibiotics in the livestock feed industry caused inevitable side effects of microbial resistance. Besides this residual antibiotics in animal-derived foodstuff imposed serious health problems for humans. So this study aimed to investigate the potential use of Bacillus velezensis to substitute antibiotics for poultry production. A total of 468, 49-week-old Hy-Line Brown chickens, were randomly divided into four groups the control group (regular diet), experiment group I (0.1% B. veleznesis ), experiment group II (0.2% B. veleznesis ), and antibiotic group (50 mg/kg flavomycin), with three replicates per group and trial period consisted on 42 days. Results The results showed that, compared with the control group, the average egg production rate and daily feed intake of experimental groups I and II increased significantly ( P  < 0.05), while the average egg weight was increased in experimental group II as compared to (I) ( P  < 0.01). The feed conversion ratio was decreased ( P > 0.05) in group (II) Egg quality parameters such as yolk weight of the experimental group II was increased, but that of the antibiotic group and experiment group I was decreased, neither significant ( P > 0.05). Moreover, the eggshell strength, yolk color, albumen height, and Haugh unit were significantly increased ( P  < 0.05). Compared with the control group, probiotic groups can increase the progesterone and motilin ( P > 0.05) but decrease the secretin and cholecystokinin in the blood plasma ( P > 0.05). Conclusions This study suggested that B. velezensis can substitute in-feed-antibiotics and improved most of the study parameters significantly. Which suggested that B. velezensis has potential future application value to replace the feed antibiotics.

An experiment was conducted comparing medicated feed additives (MFA) bambermycin or monensin sodium and tylosin phosphate in feedlot diets containing modified distillers grains (mDGS). Crossbred steers (n = 256; initial full BW 418 ± 28.5 kg) were allocated into three weight blocks in a randomized complete block design with a 2 × 2 factorial arrangement of treatments. The factors were: MFA (bambermycin at 20 mg/steer daily or monensin + tylosin at 380 and 90 mg/steer daily, respectively) and mDGS inclusion (15% and 30% of diet DM). Twenty-four pens were utilized, resulting in six replications per treatment. Steers were fed a diet consisting of a 1:1 combination of dry-rolled and high-moisture corn with the roughage portion of the diet consisting of corn silage and corn stover. Steers in the heaviest two blocks were marketed after 104 d and steers in the lightest block were marketed after 126 d. Overall average daily gain (ADG) tended (P = 0.08) to be greater for bambermycin vs. monensin and tylosin, and was not affected (P = 0.17) by mDGS level. Dry matter intake was lower (P ≤ 0.05) with 30% mDGS with monensin and tylosin than with any other treatment. Feed efficiency was not affected by mDGS, MFA, or their interaction (P ≥ 0.30). Marbling scores were greater (P = 0.01) greater for bambermycin vs. monensin and tylosin, and tended (P = 0.08) to be greater with 15% mDGS than with 30% mDGS. Carcasses from steers fed bambermycin had a greater percentage of USDA choice than those fed with monensin and tylosin (P = 0.01). Liver abscess occurrence was not affected (P ≥ 0.17) by MFA, mDGS, or their interaction. Results from this experiment indicate that including bambermycin in feedlot diets containing 30% mDGS results in increased DMI when compared with including monensin and tylosin in 30% mDGS diet without the risk for increases in liver abscess occurrence.

Peptidoglycan (PG) defines cell shape and protects bacteria against osmotic stress. The growth and integrity of PG require coordinated actions between synthases that insert new PG strands and hydrolases that generate openings to allow the insertion. However, the mechanisms of their coordination remain elusive. Moenomycin that inhibits a family of PG synthases known as Class-A penicillin-binding proteins (aPBPs), collapses rod shape despite aPBPs being non-essential for rod-like morphology in the bacterium Myxococcus xanthus . Here, we demonstrate that inhibited PBP1a2, an aPBP, accelerates the degradation of cell poles by DacB, a hydrolytic PG peptidase. Moenomycin promotes the binding between DacB and PG and thus reduces the mobility of DacB through PBP1a2. Conversely, DacB also regulates the distribution and dynamics of aPBPs. Our findings clarify the action of moenomycin and suggest that disrupting the coordination between PG synthases and hydrolases could be more lethal than eliminating individual enzymes. The integrity and maintenance of cell-wall peptidoglycan is essential for growth and cell shape in bacteria. Here, the authors show how the coordinated actions of a synthase, which inserts new peptidoglycan strands, and a hydrolase, which generates openings to allow the insertion, determine the integrity of bacterial cell wall.

In-feed antibiotics can influence intestinal microbial structures in born and early-life within a period. However, the impact of antibiotics on gut microbiota during long-term antibiotic-free and antibiotic breeding at porcine-fattening phase have not been studied extensively so far. Here, we conducted a systematic 16S rRNA gene sequencing-based study combined with metagenomic analysis to reveal the variation of diversity and function of gut microbiota between antibiotic-free (treatment group, TG) and antibiotic (a mixture of flavomycin and enramycin, control group, CG) breeding at various stages of fattening pigs. In the present study, Bacteroidetes, Firmicutes, and Proteobacteria phyla were the core microbiomes in fattening pig gut microbiota. The ratio between Firmicutes and Bacteroidetes significantly increased with age (P = 0.03). TG showed significantly higher relative abundance of Proteobacteria and Fibrobacteres phyla than CG. The microbial community can be divided into several notably clustered blocks based on cooperative and competitive correlations. These blocks centered on numerous special genera, which play essential roles in body development and disease prevention. TG showed obviously higher proportions of metabolic pathways related to metabolism, endocrine system, nervous system and excretory system, but pathways included carbohydrate metabolism and immune system diseases in CG. Collectively, this study has comprehensively demonstrated microbial diversities, differences and correlations among gut microbiota, microbial metabolism and gene functions during long-term antibiotic-free breeding. This work provides a novel resource and information with positive implications for pig husbandry production and disease prevention.

Routine use of the antibiotic flavomycin in broiler production may lead to resistance, and alternative growth promoters are used to enhance performance. Two hundred day-old male Ross 308 broiler chicks were allocated to five dietary supplements included from d 1–42: flavomycin, three possible alternatives, a probiotic, prebiotic and a synbiotic, as well as a control treatment. There were four replicate cages of 10 birds each in each treatment. Compared with the control and antibiotics treatments, the probiotic, prebiotic and synbiotic treatments increased (p = 0.001) weight gain (64, 66, 73, 70 and 74 g/d, respectively). The synbiotic treatment reduced (p = 0.004) the feed conversion ratio, compared with the control and antibiotic treatments (1.70, 1.84, 1.83, respectively). Compared with the control and antibiotic treatments, the birds fed the synbiotic treatment had greater relative gizzard (+47%) and spleen weights (+115%), and lighter kidneys (−47%). The birds fed the symbiotic treatment also had thinner walls of the caudal gut segments. The prebiotic had the most beneficial effect on cecal microbiota, stimulating aerobic and lactic acid producing bacteria and reducing Escherichia coli bacteria. Enterococci were increased in the antibiotic treatment. We conclude that there were significant performance and health benefits of using prebiotics, probiotics and synbiotics for broilers, rather than antibiotics.

Flavophospholipol (FPL) is an antimicrobial feed additive that has been approved for use in livestock animals and has the potential to decrease horizontal dissemination of antimicrobial resistance genes. Since previous studies showed that FPL has an inhibitory effect on plasmid transfer, in vitro experiments have proven the efficacy of FPL in reducing the conjugative transfer of plasmids encoding the extended-spectrum β-lactamase (ESBL) and vanA genes. These are among the most important antimicrobial resistance loci known. ESBL-producing Escherichia coli and vancomycin-resistant Enterococcus faecalis (VRE) were exposed to several concentrations of FPL, and transfer frequency and plasmid curing activity were determined. FPL inhibited the conjugative transfer of plasmids harboring ESBL and vanA genes in a concentration-dependent manner in all strains. Further transfer experiments revealed that FPL could decrease or increase transfer frequency depending on plasmid type when transfer frequency was at low levels. The plasmid curing activity of FPL was also observed in ESBL-producing E. coli in a concentration-dependent manner, suggesting that they partially contribute to the inhibition of conjugative transfer. These results suggest that the use of FPL as a feed additive might decrease the dissemination of ESBL and vanA genes among livestock animals.

In milk-fed calves, the effects of sodium-butyrate (Na-butyrate) to replace flavomycin on growth performance and some mechanisms involved were studied. Pancreatic and intestinal morphology, digestive enzyme activities, plasma gut regulatory peptide concentrations, and expression of their receptors in the gastrointestinal tract were measured. Gastrointestinal tract defense systems were examined by measuring protein levels of 2 heat-shock proteins (HSP27 and HSP70). The calves were randomly allocated into 2 groups fed the same basic diet with flavomycin as an antimicrobial growth promoter or with Na-butyrate (3 g/kg of dry matter). Sodium-butyrate disappeared quickly in the upper gut and was not found in circulating blood. Supplementation with Na-butyrate enhanced growth rate and improved feed conversion into body weight gain compared with the flavomycin group. Supplementation with Na-butyrate was likely associated with an improvement in efficacy of the gastrointestinal tract digestive capacities expressed by enhanced production of digestive enzymes and increased absorptive capacities in the upper small intestine. The effects could have been controlled by insulin-like growth factor-1 but probably not by any of the cholecystokinin/gastrin peptide family. Concentrations of HSP27 and HSP70 were increased in stomach and colon of calves receiving Na-butyrate, thereby assuring protection of cells with intensive metabolism (chaperone function). In conclusion, beneficial effects of Na-butyrate on maturation of gastrointestinal functions were shown in milk-fed calves and may be applied to young mammals of other species.

Ruta Chalepensis (fringed rue) has been used for therapeutic and aromatic purposes. However, using this plant as a natural additive in animals is scarce. A seven-week study was conducted to determine and elucidate the effects of fringed rue as a feed additive on broiler chickens growth performance and carcass characteristics. The average weight (40.08 ± 0.42 g) of 144 unsexed, day-old broiler chickens was arranged in a completely randomized design into four treatment groups. Each treatment group was divided into three replicates of twelve birds. Four treatments feed containing ground fringed rue leaves at different levels of T1 (basal diet+ the antibiotics Flavomycin at 1 g kg −1 ); T2 (basal diet + 60 g kg −1 , T3 (basal diet + 120 g kg −1 ), and T4 (basal diet + 180 g kg −1 . DM Intake was considerably high (P < 0.05) in the T3 group than in the antibiotics control group broilers. As a result, T3 groups have better improvement (P < 0.05) in final body weight, BW gain, and ADG compared to the antibiotics control in all phases. There were high improvements (P < 0.05) in dressing percentage, breast, thigh muscle, and drumsticks for chickens fed T3 and T2 than in the control group. Generally, supplementation of fringed rue up to 120 g kg −1 has no adverse effects on broiler chickens.

Sixty-week-old Hy-Line brown laying hens were randomly divided into five groups and fed different diets over a period of 84 days. Experimental treatments included a basal diet (control); the basal diet supplemented with 1.0 × 10 6 B. licheniformis yb-2 14245; the basal diet supplemented with 1.0 × 10 6 B. subtilis yb-1 14246; a combination of both strains in a 2:1 ratio (6.6 × 10 5 :3.3 × 10 5 B. licheniformis yb-2 14245: B. subtilis yb-1 14246); and the latter, added with 5 mg/kg flavomycin. Basal diet supplementation with the combined Bacillus species improved egg-laying performance in aging hens significantly ( P  < 0.05). Eggshell strength improved significantly with this treatment, compared to the control or the antibiotic-supplemented groups ( P  < 0.05). The levels of total cholesterol, triglycerides, and very low-density lipoprotein cholesterol in egg yolk declined significantly more in the Bacillus -treated group than in the control or the antibiotic-supplemented groups ( P  < 0.01). Small intestinal morphology was better in the hens treated with the Bacillus combination than in the hens in the control group ( P  < 0.05). The total number of aerobic bacteria ( Bacillus , Lactobacillus , and Bifidobacterium ) in the cecum was significantly higher in all the Bacillus -supplemented hens than either in the control or the antibiotic-supplemented hens ( P  < 0.01); additionally, the number of E. coli and Salmonella was significantly lower than in the control group ( P  < 0.01). In conclusion, diet supplementation with the combination of Bacillus species used here for aging laying hens improved their growth performance, cecal bacterial composition, egg quality, and small intestine morphology.

Background Plasmid mediated antimicrobial resistance continues to be a source of global concern, especially given the limited pipeline of novel antibiotics. The horizontal transfer of the plasmid mediated colistin resistance gene (mcr‐1) between microorganisms confer resistance to previously susceptible bacterial strains and renders colistin and polymyxin B antimicrobials ineffective. Objective To mitigate plasmid mediated colistin resistance using bambermycin and streptomycin on mcr‐1 positive field strains of Escherichia coli. Furthermore, to assess if a commercial MCR‐1 polyclonal antibody would have any synergistic effect on colistin in killing mcr‐1 gene associated colistin‐resistant E. coli in vitro. Methods Colistin‐resistant E. coli strains recovered from clinical cases were subjected to checkerboard assays and conjugation assays using varying drug combinations viz colistin, bambermycin, streptomycin, MCR‐1 antibody and human complement serum, to mitigate drug resistance. Results Following conjugation assay, the plasmid bound resistance gene was successfully transferred to J53 E. coli strain with colistin minimum inhibitory concentration (MIC) rising from ≤0.125 to >2 µg/mL conferring resistance to the former organism. The combination of bambermycin and colistin in a checkerboard assay proved to be synergistic in killing mcr‐1 associated colistin‐resistant strains. The combination of streptomycin, colistin and MCR‐1 polyclonal antibody showed additive lethal effect on mcr‐1 associated colistin‐resistant strains. Bambermycin did not interfere with the transfer of mcr‐1 bound plasmid from donors to recipient organism. Conclusion Further studies on bambermycin's mechanism of action are required, as both inhibiting and enhancing effects have been documented. Similarly, the addition of MCR‐1 polyclonal antibody in a checkerboard assay did not enhance colistin's lethal effect on mcr‐1 carrying E. coli strains, thus highlighting the need for further research. Bambermycin showed synergistic effect with colistin on mcr‐1 positive E. coli strains. Colistin and MCR‐1 antibody mixture showed additive lethal effect on mcr‐1 strains. Bambermycin had no effect on the transfer of mcr‐1 bound plasmids between organisms.