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Simple Summary: This study explored the potential of microalga Chlorella (C.) vulgaris as a sustainable protein source in broiler feed. Two trials were conducted to evaluate broilers' digestion of feeds containing varying levels of C. vulgaris. This alga was tested in two forms: unprocessed biomass and biomass processed using a pulsed electric field (PEF), a technique designed to disrupt cell walls. Broiler diets were supplemented with C. vulgaris in amounts ranging from 1–20%. The results show decreasing digestibility of protein, fat, and energy as microalgae inclusion levels increased. However, treating C. vulgaris with PEF led to improved digestibility of the feed. By exploring alternative protein sources such as microalgae, this study takes a step towards replacement of soybean meal in poultry diets. This study evaluated the feed digestibility of diets including autotrophic Chlorella (C.) vulgaris in 252 male broilers (Ross 308), comparing unprocessed biomass (trial 1) and pulsed electric field (PEF) processed biomass (trial 2) at inclusion levels up to 20%. In trial 2, performance and meat color were also evaluated. Each trial included seven treatments (0%, 1%, 2%, 5%, 10%, 15%, and 20% (%w/w on dry matter (DM)) C. vulgaris) with six replicates (three birds per replicate) per treatment. Data were analyzed using linear, quadratic, and broken-line models. Control feeds without microalgae inclusion achieved a crude protein digestibility of 82.04 ± 1.42% (trial 1) and 81.63 ± 1.90% (trial 2), while feed with 20% non-processed microalgae inclusion only had a protein digestibility of 66.96 ± 1.16% (trial 1) and feed with PEF processed microalgae at 20% had a protein digestibility of 72.75 ± 0.34% (trial 2). In general, increasing inclusion levels of C. vulgaris impaired nutrient digestibility, significantly reducing crude protein, crude fat, gross energy, and crude ash digestibility (p < 0.001). Broken-line models identified critical inclusion thresholds beyond which digestibility declined significantly, i.e., at 10% for crude protein, 12.53% for crude fat, and 9.26% for gross energy in unprocessed microalgae feeds (trial 1). For PEF-processed microalgae, only a broken line fit was obtained for gross energy, with a breakpoint at 5% (trial 2). Furthermore, a significant linear decrease in body weight (BW) (p < 0.001), average daily gain (ADG) (p < 0.001), average daily feed intake (ADFI) (p = 0.006), and relative and absolute breast filet weight was observed as microalgae inclusion level increased (trial 2). Color parameters also changed significantly with increasing microalgae inclusion level: L* showed a significant linear decrease (p = 0.029), b* and a* showed a significant linear increase (p < 0.001) (trial 2). This research advances the exploration of sustainable protein alternatives, highlighting the potential of microalgae in broiler feed and the benefits of processing methods such as PEF to enhance nutrient utilization. [ABSTRACT FROM AUTHOR]

Poultry products are an important source of foodborne Salmonella infections in humans. Amongst these, the prevalence of S. Infantis is rising. In this study, the protection efficacy of an authorized live-attenuated S. Typhimurium vaccine against S. Infantis, was examined using a seeder-bird model in broilers. Vaccinated birds displayed a significantly lower colonization of S. Infantis bacteria in the caeca compared to the non-vaccinated counterparts (P = 0.017), with no significant differences observed in the spleen among the groups, three days post-infection. Thirty-two days post-infection, the disparity in average S. Infantis concentration between all-vaccinated and non-vaccinated birds was significant in both caeca (P = 0.0003) and spleen (P = 0.0002). Interestingly, a third group, consisting of seeder birds that were not vaccinated but housed with vaccinated penmates, exhibited significantly lower S. Infantis levels in both caeca (P = 0.0014) and spleen (P < 0.0001) compared to the non-vaccinated group. These findings underscore the potential of a live-attenuated S. Typhimurium vaccine administered to 2-day-old chicks in conferring protection against S. Infantis in broilers up to slaughter age. [ABSTRACT FROM AUTHOR]

Simple Summary: The assessment of farmers' basic and practical knowledge regarding major health risks, such as poultry salmonellosis and mycotoxins, alongside the biosecurity status of farms, is crucial for effectively preventing and controlling poultry diseases in Ethiopia, where poultry production plays a vital role in community livelihoods. This research, conducted from March 2022 to June 2023, aimed to evaluate poultry farmers' basic and practical knowledge concerning salmonellosis and mycotoxins and assess the biosecurity status of small- and medium-scale poultry farms in Jimma, Ethiopia. The study revealed a low overall level of basic knowledge and poor practical knowledge among poultry farmers of managing and handling feed to reduce mycotoxin contamination and prevent Salmonella spp. infections. Furthermore, biosecurity scores were significantly below global averages, with most external biosecurity parameters and all internal measures failing to meet international standards. The findings highlighted weak biosecurity measures, inadequate awareness, and suboptimal practices among poultry farmers in Jimma. Identifying these gaps in basic and practical knowledge as well as biosecurity measures will be critical in designing and implementing effective mitigation strategies for infectious diseases in poultry farms. These results underscore the need for active engagement from all stakeholders in poultry production to boost the sector's productivity in Ethiopia. Poultry farming in Ethiopia is crucial for food security and income, but it faces significant challenges due to gaps in farmer awareness. A cross-sectional study was conducted using the Biocheck.UGent™ biosecurity scoring system and a questionnaire to evaluate poultry farmers' basic and practical knowledge concerning salmonellosis and mycotoxins. The questionnaire revealed substantial gaps in basic and practical knowledge regarding Salmonella spp infections and mycotoxin among 38 poultry farmers in Jimma. About 68.4% of farmers were unaware of the impact of salmonellosis on both poultry and human health. Moreover, 78.9% had limited basic knowledge of how salmonellosis affects production and the economy. Farmers also showed limited practical knowledge of farm management and hygiene practices essential for preventing Salmonella spp. infections. Regarding mycotoxins, 63.2% of farmers lacked awareness of poultry feed management, 60.5% were unaware of the health risks mycotoxins pose, and 73.7% did not recognize signs of mycotoxin contamination. Although 55.3% of farmers demonstrated acceptable practical knowledge of strategies to reduce the impact of mycotoxin contaminations, there are still concerns, particularly since 65.8% and 55.3% only showed moderate practical knowledge of feed storage and mycotoxin prevention, respectively. The overall biosecurity scores of poultry farms were below the global average, with a score of 41.7 compared to the worldwide average of 64. The overall mean score for external biosecurity was 44.9, below the global average of 63. All 3 scoring platforms and biosecurity parameters indicated that internal biosecurity was the weakest aspect, with a score of 31.6, well below the global standard of 64. The results showed a weak correlation (rₛ = 0.06) between farmers' basic and practical knowledge scores about Salmonella spp. infections and mycotoxins. Similarly, there was a weak correlation between the poor biosecurity score of poultry farms and the basic and practical knowledge of poultry farmers on Salmonella spp. infections (rₛ = 0.17) and mycotoxins (rₛ = 0.25). In conclusion, the study found that poultry farmers in Jimma had poor basic and practical knowledge scores on Salmonella, mycotoxins, and biosecurity measures. Thus, awareness creation is paramount to improve these gaps to reduce the impact of mycotoxin contamination and poultry diseases and consequently to improve food security and food safety. [ABSTRACT FROM AUTHOR]

Clostridium perfringens causes many different histotoxic and enterotoxic diseases in humans and animals as a result of its ability to produce potent protein toxins, many of which are extracellular. The current scheme for the classification of isolates was finalized in the 1960s and is based on their ability to produce a combination of four typing toxins - α-toxin, β-toxin, ε-toxin and ι-toxin - to divide C. perfringens strains into toxinotypes A to E. However, this scheme is now outdated since it does not take into account the discovery of other toxins that have been shown to be required for specific C. perfringens-mediated diseases. We present a long overdue revision of this toxinotyping scheme. The principles for the expansion of the typing system are described, as is a mechanism by which new toxinotypes can be proposed and subsequently approved. Based on these criteria two new toxinotypes have been established. C. perfringens type F consists of isolates that produce C. perfringens enterotoxin (CPE), but not β-toxin, ε-toxin or ι-toxin. Type F strains will include strains responsible for C. perfringens-mediated human food poisoning and antibiotic associated diarrhea. C. perfringens type G comprises isolates that produce NetB toxin and thereby cause necrotic enteritis in chickens. There are at least two candidates for future C. perfringens toxinotypes, but further experimental work is required before these toxinotypes can formally be proposed and accepted.

Salmonellosis represents a significant economic and public health concern for the poultry industry in Africa, leading to substantial economic losses due to mortality, reduced productivity, and food safety problems. However, comprehensive information on the burden of poultry salmonellosis at the continental level is scarce. To address this gap, a systematic review and meta-analysis were conducted to consolidate information on the prevalence and circulating serotypes of poultry salmonellosis in African countries. This involved the selection and review of 130 articles published between 1984 and 2021. A detailed systematic review protocol was structured according to Cochrane STROBE and PRISMA statement guideline. From the 130 selected articles from 23 different African countries, the overall pooled prevalence estimate (PPE) of poultry salmonellosis in Africa was found to be 14.4% (95% CI = 0.145–0.151). Cameroon reported the highest PPE at 71.9%. The PPE was notably high in meat and meat products at 23%. The number of research papers reporting poultry salmonellosis in Africa has shown a threefold increase from 1984 to 2021. Salmonella Enteritidis and Typhimurium were the two most prevalent serotypes reported in 18 African countries. Besides, Salmonella Kentucky, Virchow, Gallinarum, and Pullorum were also widely reported. Western Africa had the highest diversity of reported Salmonella serotypes (141), in contrast to southern Africa, which reported only 27 different serotypes. In conclusion, poultry salmonellosis is highly prevalent across Africa, with a variety of known serotypes circulating throughout the continent. Consequently, it is crucial to implement strategic plans for the prevention and control of Salmonella in Africa. RESEARCH HIGHLIGHTS The pooled sample prevalence of poultry salmonellosis in Africa is high (14.4%). The highest PPE was recorded in meat and meat products. Salmonella serotypes of zoonotic importance were found in all sample types. Salmonella Enteritidis and Typhimurium are common serotypes spreading in Africa. [ABSTRACT FROM AUTHOR]

The interaction between bacteria and the intestinal mucus is crucial during the early pathogenesis of many enteric diseases in mammals. A critical step in this process employed by both commensal and pathogenic bacteria focuses on the breakdown of the protective layer presented by the intestinal mucus by mucolytic enzymes. C. perfringens type G, the causative agent of necrotic enteritis in broilers, produces two glycosyl hydrolase family 18 chitinases, ChiA and ChiB, which display distinct substrate preferences. Whereas ChiB preferentially processes linear substrates such as chitin, ChiA prefers larger and more branched substrates, such as carbohydrates presented by the chicken intestinal mucus. Here, we show via crystal structures of ChiA and ChiB in the apo and ligand-bound forms that the two enzymes display structural features that explain their substrate preferences providing a structural blueprint for further interrogation of their function and inhibition. This research focusses on the roles of ChiA and ChiB in bacterial proliferation and mucosal attachment, two processes leading to colonization and invasion of the gut. ChiA and ChiB, either supplemented or produced by the bacteria, led to a significant increase in C. perfringens growth. In addition to nutrient acquisition, the importance of chitinases in bacterial attachment to the mucus layer was shown using an in vitro binding assay of C. perfringens to chicken intestinal mucus. Both an in vivo colonization trial and a necrotic enteritis trial were conducted, demonstrating that a ChiA chitinase mutant strain was less capable to colonize the intestine and was hampered in its disease-causing ability as compared to the wild-type strain. Our findings reveal that the pathogen-specific chitinases produced by C. perfringens type G strains play a fundamental role during colonization, suggesting their potential as vaccine targets. Author summary: The intestinal mucus layer protects the intestinal mucosa from invasion by pathogenic bacteria. However, it is precisely this first line of protection that invading bacteria aim to break down en route to colonizing the gut. Clostridium perfringens type G, the causative agent of necrotic enteritis in broiler chickens, an enteric disease characterised by ulcers in the small intestine, employs such a pathogenic strategy. In addition to the well-studied NetB toxin, this bacterium can produce other pathogen-specific enzymes, some of which could play a central role during disease development. Two of these enzymes were identified as putative chitinases, ChiA and ChiB. We have demonstrated that ChiA and ChiB are indeed functional enzymes that can hydrolyze a wide variety of substrates, with ChiA preferring mucus as a substrate. Mucus breakdown by the chitinases induces both bacterial proliferation and attachment to mucus, two processes that are crucial in the first steps of the pathogenesis. In addition, we have shown that a ChiA mutant strain does not efficiently colonize the intestine and causes less severe lesions as compared to the wild-type strain. Thus, we conclude that chitinases provide an advantage to the pathogen to facilitate colonization of the intestine of broiler chickens. [ABSTRACT FROM AUTHOR]

Enterococcus cecorum is associated with bacterial chondronecrosis with osteomyelitis (BCO) in broilers. Prophylactic treatment with antimicrobials is common in the poultry industry, and, in the case of outbreaks, antimicrobial treatment is needed. In this study, the minimum inhibitory concentrations (MICs) and epidemiological cutoff (ECOFF) values (COWT) for ten antimicrobials were determined in a collection of E. cecorum strains. Whole-genome sequencing data were analyzed for a selection of these E. cecorum strains to identify resistance determinants involved in the observed phenotypes. Wild-type and non-wild-type isolates were observed for the investigated antimicrobial agents. Several antimicrobial resistance genes (ARGs) were detected in the isolates, linking phenotypes with genotypes for the resistance to vancomycin, tetracycline, lincomycin, spectinomycin, and tylosin. These detected resistance genes were located on mobile genetic elements (MGEs). Point mutations were found in isolates with a non-wild-type phenotype for enrofloxacin and ampicillin/ceftiofur. Isolates showing non-wild-type phenotypes for enrofloxacin had point mutations within the GyrA, GyrB, and ParC proteins, while five amino acid changes in penicillin-binding proteins (PBP2x superfamily) were observed in non-wild-type phenotypes for the tested β-lactam antimicrobials. This study is one of the first that describes the genetic landscape of ARGs within MGEs in E. cecorum, in association with phenotypical resistance determination. [ABSTRACT FROM AUTHOR]

As a result of rapid growth of broilers, bacterial chondronecrosis with osteomyelitis has emerged in the last decade, with bacterial translocation from the gut to internal organs, including the femur head. In this study, we isolated translocated bacteria in femur heads, blood, and liver, during ageing of broilers, and identified the bacteria using 16S rDNA sequencing. We also provided histopathological descriptions of femur head lesions. Bacteria were isolated from blood, liver, and femoral head samples. In the femoral heads, an age-related presence of bacteria was observed, with high prevalence at 2 days post-hatch, and no bacteria isolated from femoral heads of broilers older than 14 days. Bacterial identification using 16S rRNA gene sequencing demonstrated that bacteria present in blood, liver, and femur belonged to different taxonomic groups. Bacteria isolated from blood and liver samples belonged predominantly to the Enterobacteriaceae, Enterococcaceae, and Staphylococcaceae, while Escherichia/Shigella and Enterococcus spp. were the most prevalent taxa in femoral head samples. No bacteria were isolated from the femoral head of any of the birds with histopathological lesions. All 19-day-old and 22-day-old birds in this study showed cartilage retention in both legs, and had signs of separation between the articular cartilage and the growth cartilage in one or both legs. This study shows that young clinically healthy broilers have a higher prevalence of bacteria in the femoral head compared to older broilers and that presence of bacteria in blood and liver is common during ageing of broilers. Large number of bacteria isolated from femoral heads of clinically healthy broilers. The prevailing taxa in femoral heads were Escherichia/Shigella and Enterococcus spp. Continuous presence of bacteria in blood and liver of clinically healthy broilers. Enterobacteriaceae, Enterococcaceae, and Staphylococcaceae prevail in blood and liver. [ABSTRACT FROM AUTHOR]