Investigating the cecal microbiota of broilers raised in extensive and intensive production systems.

Intensive broiler production practices are structured to prevent the introduction and spread of pathogens; however, they can potentially minimize the exposure of broilers to beneficial commensal bacteria. In this study, we used 16S rRNA amplicon sequencing to characterize the cecal microbiota of 35-day-old broilers from 22 independent commercial farms rearing broilers under intensive (IPS) or extensive production systems (EPS). We aimed to determine which bacteria are normal inhabitants of the broiler ceca and which bacteria might be missing from broilers in IPS. In addition, we generated a collection of 410 bacterial isolates, including 87 different species, to be used as a resource to further explore the effects of selected isolates on bird physiology and to elucidate the role of individual species within the cecal microbial community. Our results indicated significant differences in the microbiota of broilers between systems: the microbiota of broilers from EPS was dominated by Bacteroidetes {55.2% ± 8.9 [mean ± standard deviation (SD)]}, whereas Firmicutes dominated the microbiota of broilers from IPS (61.7% ± 14.4, mean ± SD). Bacterial taxa found to be core in the EPS microbiota, including Olsenella, Alistipes, Bacteroides, Barnesiella, Parabacteroides, Megamonas, and Parasutterella, were shown to be infrequent or absent from the IPS microbiota, and the EPS microbiota presented higher phylogenetic diversity and greater predicted functional potential than that of broilers in IPS. The bacteria shown to be depleted in broilers from IPS should be further investigated for their effects on bird physiology and potential application as next-generation probiotics. IMPORTANCE Production practices in intensive farming systems significantly reduce the introduction and spread of pathogens; however, they may potentially minimize the exposure of animals to beneficial commensal microorganisms. In this study, we identified core bacteria from the cecal microbiota of broilers raised in extensive production systems that are missing or reduced in birds from intensive systems, including Olsenella, Alistipes, Bacteroides, Barnesiella, Parabacteroides, Megamonas, and Parasutterella. Furthermore, the cecal microbiota of broilers from extensive systems showed higher diversity and greater functional potential than that of broilers from intensive systems. In addition, a collection of bacterial isolates containing 87 different species was generated from the current study, and this important resource can be used to further explore the role of selected commensal bacteria on the microbial community and bird physiology.

Cecal Microbiota Development and Physiological Responses of Broilers Following Early Life Microbial Inoculation Using Different Delivery Methods and Microbial Sources.

Broilers in intensive systems may lack commensal microbes that have coevolved with chickens in nature. This study evaluated the effects of microbial inocula and delivery methods applied to day-old chicks on the development of the cecal microbiota. Specifically, chicks were inoculated with cecal contents or microbial cultures, and the efficacies of three delivery methods (oral gavage, spraying inoculum into the bedding, and cohousing) were evaluated. Also, a competitive study evaluated the colonization ability of bacteria sourced from extensive or intensive poultry production systems. The microbiota of inoculated birds presented higher phylogenetic diversity values (PD) and higher relative abundance values of Bacteroidetes, compared with a control. Additionally, a reduction in the ileal villus height/crypt depth ratio and increased cecal IL-6, IL-10, propionate, and valerate concentrations were observed in birds that were inoculated with cecal contents. Across the experiments, the chicks in the control groups presented higher relative abundance values of Escherichia/Shigella than did the inoculated birds. Specific microbes from intensively or extensively raised chickens were able to colonize the ceca, and inocula from intensive production systems promoted higher relative abundance values of Escherichia/Shigella. We concluded that Alistipes, Bacteroides, Barnesiella, Mediterranea, Parabacteroides, Megamonas, and Phascolarctobacterium are effective colonizers of the broiler ceca. In addition, oral gavage, spray, and cohousing can be used as delivery methods for microbial transplantation, as indicated by their effects on the cecal microbiota, intestinal morphology, short-chain fatty acids concentration, and cytokine/chemokine levels. These findings will guide future research on the development of next-generation probiotics that are able to colonize and persist in the chicken intestinal tract after a single exposure. IMPORTANCE The strict biosecurity procedures employed in the poultry industry may inadvertently hinder the transmission of beneficial commensal bacteria that chickens would encounter in natural environments. This research aims at identifying bacteria that can colonize and persist in the chicken gut after a single exposure. We evaluated different microbial inocula that were obtained from healthy adult chicken donors as well as three delivery methods for their effects on microbiota composition and bird physiology. In addition, we conducted a competitive assay to test the colonization abilities of bacteria sourced from intensively versus extensively raised chickens. Our results indicated that some bacteria are consistently increased in birds that are exposed to microbial inoculations. These bacteria can be isolated and employed in future research on the development of next-generation probiotics that contain species that are highly adapted to the chicken gut.

The Use of Disinfectant in Barn Cleaning Alters Microbial Composition and Increases Carriage of Campylobacter jejuni in Broiler Chickens.

To maintain food safety and flock health in broiler chicken production, biosecurity approaches to keep chicken barns free of pathogens are important. Canadian broiler chicken producers must deep clean their barns with chemical disinfectants at least once annually (full disinfection [FD]) and may wash with water (water wash [WW]) throughout the year. However, many producers use FD after each flock, assuming a greater efficacy of more stringent cleaning protocols, although little information is known regarding how these two cleaning practices affect pathogen population and gut microbiota. In the present study, a crossover experiment over four production cycles was conducted in seven commercial chicken barns to compare WW and FD. We evaluated the effects of barn cleaning methods on commercial broiler performance, cecal microbiota composition, Campylobacter and Salmonella occurrence, and Campylobacter jejuni and Clostridium perfringens abundance, as well as on short-chain fatty acid (SCFA) concentrations in the month-old broiler gut. The 30-day body weight and mortality rate were not affected by the barn cleaning methods. The WW resulted in a modest but significant effect on the structure of broiler cecal microbiota (weighted-UniFrac; adonis P = 0.05, and unweighted-UniFrac; adonis P = 0.01), with notable reductions in C. jejuni occurrence and abundance. In addition, the WW group had increased cecal acetate, butyrate, and total SCFA concentrations, which were negatively correlated with C. jejuni abundance. Our results suggest that WW may result in enhanced activity of the gut microbiota and reduced zoonotic transmission of C. jejuni in broiler production relative to FD in the absence of a disease challenge. IMPORTANCE We compared the effects of barn FD and WW methods on gut microbial community structures and pathogen prevalence of broiler chickens in a nonchallenging commercial production setting. The results revealed that barn cleaning methods had little impact on the 30-day body weight and mortality rate of broiler chickens. In addition, the FD treatment had a subtle but significant effect on the broiler cecal microbiota with increased abundances of Campylobacter and decreased SCFA concentrations, which would support the adoption of WW as a standard practice. Thus, compared to FD, WW can be beneficial to broiler chicken production by inhibiting zoonotic pathogen colonization in the chicken gut with reduced cost and labor of cleaning.

Alternatives to antibiotics in diets of weaned piglets / Alternativas de antibióticos para leitões desmamados

ABSTRACT: This experiment was conducted to evaluate the effect of growth promoter additives an alternative to antibiotics on performance, intestinal morphology and on microbiota of 21-to-35-day-old piglets. A total of 160 commercial crossbred piglets (males and females) with initial weight of 6.10±0.709kg were allotted in a completely randomized design with five treatments: Basal diet - Negative Control (NC); Basal diet + antibiotic (PC); Basal diet + mannanoligosaccharides (MOS); Basal diet + organic acids (OA), Basal diet + mannanoligosacharides + organic acids (MOS+OA), eight replicates and four piglets per experimental unit. The inclusion of additives in the diets had no effect (P>0.05) on the final average weight of piglets. Similarly, no effects (P<0.05) were observed on average daily feed intake and on average daily weight gain. The feed conversion improved (P<0.01) with the inclusion of additives in the diets compared to piglets fed with the NC. There was no effect (P>0.05) of the dietary additives on intestinal morphology and microbiota composition (enterobacteria and lactobacilli). Use of antibiotics, prebiotics, organic acids or prebiotics associated with organic acids in the diet improves feed conversion of piglets from 21 to 35 days of age. The additives have no major effects on piglets' intestinal morphology and microbiota.

RESUMO: O experimento foi conduzido com o objetivo de avaliar o efeito de aditivos promotores de crescimento como alternativa ao uso de antibióticos no desempenho, na morfologia intestinal e na microbiota de leitões dos 21 aos 35 dias de idade. Um total de 160 leitões híbridos comerciais, machos castrados e fêmeas, com peso inicial de 6,10±0,709kg, foram distribuídos em delineamento inteiramente casualizado, com cinco tratamentos: Ração basal - Controle Negativo (CN); Ração basal + antibiótico (CP); Ração basal +mananoligossacarídeo (MOS); Ração basal + ácido orgânico (AO); Ração basal + mananoligossacarídeo + ácido orgânico (MOS+AO), oito repetições e quarto animais por unidade experimental. A inclusão dos aditivos não teve efeito (P>0,05) no peso médio final dos leitões. Da mesma forma, não foram observados efeitos (P>0,05) dos aditivos no consumo de ração médio diário. A conversão alimentar melhorou (P<0,01) com a inclusão dos aditivos na ração comparados com os animais alimentados com a ração CN. Não houve efeito (P>0,05) dos aditivos na morfologia do epitélio intestinal e na composição da microbiota (enterobactérias e lactobacilos). A utilização de antibiótico, probióticos, ácidos orgânicos ou de probióticos associado com ácidos orgânicos na ração melhora a conversão alimentar de leitões, dos 21 aos 34 dias de idade. Os aditivos não tiveram efeitos na morfologia intestinal e na microbiota dos leitões.