Molecular detection of Eimeria species and Clostridium perfringens in poultry dust and pooled excreta of commercial broiler chicken flocks differing in productive performance

Spatial distribution of airborne bacterial communities in caged poultry houses

Microbial aerosols in intensive broiler houses whose species and concentrations are closely related to human health are ubiquitous. Based on 16S rRNA gene sequencing, the aim of this study was to investigate the spatial distribution and diversity of bacterial aerosols in the air of broiler houses. Significant spatial variations in airborne bacterial concentrations were observed inside the poultry farmhouse. The results indicated that bacteria in the air samples could be grouped into a total of 1,674 OTUs. Alpha diversity analysis showed that the diversity of the microbial community at the entry of the broiler house was higher than that at the middle or the rear (p < 0.01). The Sankey diagram illustrated species dynamic changes in Proteobacteria, Firmicutes, and Actinobacteria among the different locations. From the aspect of LEfSe (LDA Effect Size) analysis, we discovered that the abundance of Planctomycetes was significantly higher in the entry than in the rear and middle. This study shows the spatial distribution of the entire bacterial community in intensive broiler houses, which offers a new perspective for studying airborne total bacteria in those environments.Implications: The bacteria contained in air aerosols from poultry houses are closely connected to animal health and production. This study aimed to investigate the spatial distribution and diversity of bacterial aerosols in the air of broiler houses. The results observed that bacterial aerosol concentrations in the examined broilers house varied greatly at different positions, and a significantly higher exposure to bacterial aerosol was observed at the middle than at the other positions (p < 0.05). The alpha diversity analysis showed that the diversity of the microbial community at the entry of the broiler house was higher than that at the middle or the rear (P<0.01). Sankey diagram illustrated species dynamic changes of Proteobacteria, Firmicutes and Actinobacteria among the different locations. The microbial communities in genus level in the samples of entry and rear were closer, while the species diversity of middle and rear samples in chicken house was highly similar (P>0.05). Altogether, results revealed that the effects of spatial factors on the diversity and abundance of bacteria in the air of closed-cage broiler houses, which poses a potential threat to the health of animals and workers in those environments.

Phenotypical Identification and Toxinotyping of Clostridium perfringens Isolates from Healthy and Enteric Disease-Affected Chickens

Clostridium perfringens is a ubiquitous spore-forming anaerobic pathogen that is frequently associated with enteric disease in chickens. Moreover, enterotoxin-producing C. perfringens has high zoonotic potential as well as serious public health concerns due to the emanation of food-borne intoxication. The present study was designed to isolate, identify, and toxinotype C. perfringens from both healthy and cases of necrotic or ulcerative enteritis chickens. A total of 110 samples were collected from July 2019 to February 2021. Among the samples, 38 (34.5%, 95% CI: 26.39-43.83) were positive for C. perfringens and were obtained from broiler 21 (33.3%, 95% CI: 22.91-45.67), Sonali 9 (34.6%, 95% CI: 19.31-53.88), and layer 8 (38%, 95% CI: 20.68-59.20). C. perfringens was highly prevalent (35.7%, 95% CI: 25.48-47.44) in enteritis chickens compared with healthy ones. In multiplex PCR toxinotyping, 34 (89.4%) isolates were identified as C. perfringens type A by the presence of the alpha toxin gene (cpa). Moreover, in addition to the cpa gene, 3 (14.3%, 95% CI: 4.14-35.48) broiler and 1 (11.1%, 95% CI: 0.01-45.67) Sonali isolates harbored the enterotoxin gene (cpe) and were classified as type F. However, none of the isolates carried genes encoding beta (cpb), epsilon (etx), iota (iap), or beta-2 (cpb2) toxins. Multivariable logistic regression analysis identified the following variables such as; "previously used litter materials" (OR 21.77, 95% CI 2.22-212.66, p ≤ 0.008); intestinal lesions, "presence of ulceration" (OR 30.01, 95% CI 3.02-297.91, p ≤ 0.004); "ballooned with gas" (OR 24.74, 95% CI 4.34-140.86, p ≤ 0.001) and "use of probiotics" (OR 5.24, 95% CI 0.74-36.75, p ≤ 0.095) act as risk factors for C. perfringens colonization in chicken gut. This is the first study of molecular toxinotyping of C. perfringens from healthy and enteric-diseased chickens in Bangladesh, which might have a potential food-borne zoonotic impact on human health.

Centennial Review: Factors affecting the chicken gastrointestinal microbial composition and their association with gut health and productive performance

Maintenance of "gut health" is considered a priority in commercial chicken farms, although a precise definition of what constitutes gut health and how to evaluate it is still lacking. In research settings, monitoring of gut microbiota has gained great attention as shifts in microbial community composition have been associated with gut health and productive performance. However, microbial signatures associated with productivity remain elusive because of the high variability of the microbiota of individual birds resulting in multiple and sometimes contradictory profiles associated with poor or high performance. The high costs associated with the testing and the need for the terminal sampling of a large number of birds for the collection of gut contents also make this tool of limited use in commercial settings. This review highlights the existing literature on the chicken digestive system and associated microbiota; factors affecting the gut microbiota and emergence of the major chicken enteric diseases coccidiosis and necrotic enteritis; methods to evaluate gut health and their association with performance; main issues in investigating chicken microbial populations; and the relationship of microbial profiles and production outcomes. Emphasis is given to emerging noninvasive and easy-to-collect sampling methods that could be used to monitor gut health and microbiological changes in commercial flocks.

Anticoccidial efficacy of Garcinia kola (Heckel H.) against experimental Eimeria tenella infection in chicks

There is a need to advance commercial poultry production to cater to the essential protein needs of an ever-increasing population, however, the rampant occurrence of coccidiosis infection poses a threat to this achievement. This study evaluated the in vivo anticoccidial activities of the extracts and fractions of Garcinia kola against experimental Eimeria tenella infection using broiler chickens as experimental subjects. A total of 40 broiler chicks were experimentally infected with E. tenella and assigned randomly into five groups consisting of eight chicks each. Three days post experimental infection groups I and II were administered orally with tween 80 (0.8%) and Amprolium (30 mg/kg) and served as untreated and treated control groups, respectively whereas Groups III, IV, and V were administered orally with crude methanol extract (CME) at doses of 200, 400 and 600 mg/kg, respectively, for five consecutive days. Daily weight gains were recorded and faecal oocysts per gram (OPG) counts were made by the McMaster Egg counting technique. Blood samples from each experimental group were collected on days 0, 3, 6, and 8 for haematological examination. In the acute toxicity studies, the CME of G. kola did not produce any toxic effect or mortality at doses between 10 and 5000 mg/kg. The CME G. kola was then considered safe and the LD50 was assumed to be > 5000 mg/kg. Graded doses of CME of G. kola considerably (P < 0.05) improved body weight gain and decreased OPG in a dose-depended manner. There was also significant improvement in the Packed Cell Volume (PCV), Red Blood Cell (RBC) and White Blood Cell (WBC) counts upon treatment with the graded doses of CME of G. kola. Besides, G. kola significantly decreased histopathological lesions in the caecum. The results of this study indicates that G. kola may provide beneficial effects against E. tenella-induced coccidiosis in broiler chickens.

Microbial taxa in dust and excreta associated with the productive performance of commercial meat chicken flocks

BACKGROUND

A major focus of research on the gut microbiota of poultry has been to define signatures of a healthy gut and identify microbiota components that correlate with feed conversion. However, there is a high variation in individual gut microbiota profiles and their association with performance. Population level samples such as dust and pooled excreta could be useful to investigate bacterial signatures associated with productivity at the flock-level. This study was designed to investigate the bacterial signatures of high and low-performing commercial meat chicken farms in dust and pooled excreta samples. Poultry house dust and fresh pooled excreta were collected at days 7, 14, 21, 28 and 35 of age from 8 farms of two Australian integrator companies and 389 samples assessed by 16S ribosomal RNA gene amplicon sequencing. The farms were ranked as low (n = 4) or high performers (n = 4) based on feed conversion rate corrected by body weight.

RESULTS

Permutational analysis of variance based on Bray-Curtis dissimilarities using abundance data for bacterial community structure results showed that company explained the highest variation in the bacterial community structure in excreta (R² = 0.21, p = 0.001) while age explained the highest variation in the bacterial community structure in dust (R² = 0.13, p = 0.001). Farm performance explained the least variation in the bacterial community structure in both dust (R² = 0.03, p = 0.001) and excreta (R² = 0.01, p = 0.001) samples. However, specific bacterial taxa were found to be associated with high and low performance in both dust and excreta. The bacteria taxa associated with high-performing farms in dust or excreta found in this study were Enterococcus and Candidatus Arthromitus whereas bacterial taxa associated with low-performing farms included Nocardia, Lapillococcus, Brachybacterium, Ruania, Dietzia, Brevibacterium, Jeotgalicoccus, Corynebacterium and Aerococcus.

CONCLUSIONS

Dust and excreta could be useful for investigating bacterial signatures associated with high and low performance in commercial poultry farms. Further studies on a larger number of farms are needed to determine if the bacterial signatures found in this study are reproducible.

Microbial communities of poultry house dust, excreta and litter are partially representative of microbiota of chicken caecum and ileum

Traditional sampling methods for the study of poultry gut microbiota preclude longitudinal studies as they require euthanasia of birds for the collection of caecal and ileal contents. Some recent research has investigated alternative sampling methods to overcome this issue. The main goal of this study was to assess to what extent the microbial composition of non-invasive samples (excreta, litter and poultry dust) are representative of invasive samples (caecal and ileal contents). The microbiota of excreta, dust, litter, caecal and ileal contents (n = 110) was assessed using 16S ribosomal RNA gene amplicon sequencing. Of the operational taxonomic units (OTUs) detected in caecal contents, 99.7% were also detected in dust, 98.6% in litter and 100% in excreta. Of the OTUs detected in ileal contents, 99.8% were detected in dust, 99.3% in litter and 95.3% in excreta. Although the majority of the OTUs found in invasive samples were detected in non-invasive samples, the relative abundance of members of the microbial communities of these groups were different, as shown by beta diversity measures. Under the conditions of this study, correlation analysis showed that dust could be used as a proxy for ileal and caecal contents to detect the abundance of the phylum Firmicutes, and excreta as a proxy of caecal contents for the detection of Tenericutes. Similarly, litter could be used as a proxy for caecal contents to detect the abundance of Firmicutes and Tenericutes. However, none of the non-invasive samples could be used to infer the overall abundance of OTUs observed in invasive samples. In conclusion, non-invasive samples could be used to detect the presence and absence of the majority of the OTUs found in invasive samples, but could not accurately reflect the microbial community structure of invasive samples.