Sub-Clinical Necrotic Enteritis (SCNE), caused by toxin-producing Clostridium perfringens, is a major challenge in poultry production. SCNE has traditionally been managed with in-feed antibiotics; however, increasing concerns about the spread of antimicrobial resistance call for antibiotic-free strategies for its control. We recently described an NE control strategy leveraging Limosilactobacillus reuteri probiotic strains genetically engineered to deliver nanobodies against alpha toxin and NetB from C. perfringens in the poultry gut. Here, in a controlled study under SCNE conditions, we found that the engineered strains significantly improved feed conversion ratios and weight gain of broilers, outperforming treatment with either a prophylactic antibiotic or the wild-type probiotic strains. To investigate the systemic factors contributing to these performance differences, we analyzed histomorphometrics of the small intestine, microbial metatranscriptomics of jejunal contents, and gene expression from the jejunum and liver tissues. Our results confirmed the in situ expression of the nanobodies and provided evidence that nanobody delivery mitigates SCNE-associated inflammation in the jejunum and toxin-induced damage in the liver, leading to a more quiescent immune state, lower oxidative stress, and improved growth performance. Our findings demonstrate the potential of probiotic-vectored nanobody delivery as an effective strategy for targeting gut antigens across a range of diseases.

Association between Heterakis dispar infections and concurrent diseases in reproductive geese: A retrospective necropsy study.

Identification and evaluation of novel antigens PykA, CPE1060 and Mbp as G-type Clostridium perfringens subunit vaccines.

Biofilm formation by clinical Clostridium perfringens isolates and its suppression by thymol.

Efficacy of Soybean Meal Bioactive Peptides Individually or in Combination with Acidified Drinking Water on Growth performance, Gut Health, and Welfare Aspects in Broiler Chickens Under Necrotic Enteritis Challenge

ABSTRACT Necrotic enteritis (NE) is a disease affecting poultry caused by virulence factors, primarily toxins, produced by Clostridium perfringens (Cp). Although NE is well documented in turkey flocks, only one study describes its pathogenesis suggesting a protocol for the induction of the disease. The aim of this study was to set up a challenge model for the experimental reproduction of NE in turkeys, in line with clinical signs currently observed in the field. To this purpose, the disease was induced based on the administration of some well-known predisposing factors for chicken (sudden switch to a high protein diet, coccidia) and challenging the birds with Cp strains with different genetic virulence factors isolated from chicken and turkey affected by NE. The predisposing factors were administered to three experimental groups (T02, T03, T04). In addition, groups T03 and T04 were challenged with Cp isolated from chicken or turkey, respectively. Group T01 served as the negative control. Clinical signs, gross pathology and histopathological lesions were scored and compared between groups. The challenge with the chicken Cp strain induced clinical manifestations of NE (80% mortality) and reproduced lesions both macroscopically and microscopically. In groups challenged with Cp, gross pathology revealed more severe lesions (P < 0.001) when compared to the group challenged with the predisposing factors only. Histopathologically, those findings were confirmed only in group T03 in the jejunum (P < 0.001). This experimental model will be useful to test the efficacy of control/preventive measures and to better understand the virulence factors involved in the pathogenesis of NE in turkeys. RESEARCH HIGHLIGHTS Not all Clostridium perfringens (Cp) strains can reproduce severe necrotic enteritis (NE) in turkeys. The developed NE reproduction model caused 80% mortality. A reliable NE reproduction model is crucial to investigate pathogenic Cp strains.

Necrotic enteritis (NE) caused by coccidia and Clostridium perfringens (CCP) infection poses significant economic losses in poultry production. The present study aimed to identify the potential beneficial effects of Lactobacillus reuteri (LR) postbiotics on broilers under necrotic enteritis challenge. A total of 180 Arbor Acres+ broilers were randomly assigned to three groups: control group (CTR, fed basal diet), CCP group (challenged with CCP) and LR + CCP group (100 mg/kg LR with CCP infection). The formal animal experiment lasted for 28 days. The results showed that LR + CCP group exhibited higher body weight on days 19 and 28 compared with the CCP group, along with increased average daily feed intake and average daily gain during days 1–18, 19–28 and 1–28 (P < 0.05). The LR supplementation significantly reduced plasma diamine oxidase and lysozyme levels, increased jejunal villus height and ileal Claudin-1 and Mucin2 expression of NE-challenged broilers (P < 0.05). It down-regulated ileal IL-1β, IFN-γ, NOD1 and TGF-β expression and up-regulated jejunal MHC-II and ileal Leap2 expression of challenged broilers (P < 0.05). Furthermore, LR supplementation decreased ileal Firmicutes and Proteobacteria and increased Bacteroidota abundance (P < 0.05). In summary, dietary LR improved intestinal morphology, mitigated intestinal inflammation, and modulated ileal microbiota, contributing to the improvement of intestinal health and growth performance of NE-challenged broilers.

Clostridium perfringens is an opportunistic Gram-positive bacterium that causes necrotic enteritis and other severe infections in animals, as well as food poisoning in humans. In this study, we introduce a framework consisting of rpoB sequence typing (RSTing) and network analysis to investigate the evolutionary trajectories of C. perfringens. By analyzing 319 rpoB sequences—300 from public databases and 19 newly sequenced isolates from chicken and cattle sources—we identified 84 rpoB sequence types (RSTs). Among them, the early emerging RST 1-1 was the most prevalent (21.3%), while the putative ancestral type, RST 0, was the fifth most common (4.7%). The high RST diversity and the predominance of RST 1-1, mainly from chickens, suggest that chickens may serve as an important reservoir. By integrating virulence gene profiling, MLST, and comparative genomics, we separated identical RSTs into distinct genotypes and uncovered genomic evidence of possible interspecies transmission between chickens and cattle, two major food-producing species. These findings indicate that RSTing provides a useful complementary approach to investigating the evolutionary and epidemiological dynamics of C. perfringens.

Vaccination with a novel quadrivalent fusion protein protects chickens against necrotic enteritis lesions caused by Clostridium perfringens.

Molecular detection and sequencing of the NetB toxin Gene of clostridium perfringens and evaluation of its pathogenicity in broiler chicken.

Evaluation of Lysozyme Supplementation on Antioxidant Status, Immune Gene Expression, and Amelioration of Necrotic Enteritis in Broiler Chickens

Genetic basis of disease resistance to coccidiosis and necrotic enteritis in chickens

Clostridium perfringens is known to cause intestinal infections in both humans and poultry, highlighting the importance of identifying highly effective, low-toxicity natural products for treating necrotic enteritis (NE) caused by this bacterium. This study aimed to identify carbon dots (CDs), derived from natural products with the most potent antibacterial effect against C. perfringens, optimize their preparation conditions, and characterize them structurally and compositionally. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the microdilution method. To further investigate the antibacterial mechanism in vitro, time-kill curves were generated, and experiments were conducted to assess protein and nucleic acid leakage. The results demonstrated that the selected Phellodendri chinensis cortex carbon dots (PCC-CDs) effectively damaged the cell membrane of C. perfringens, leading to the leakage of proteins and nucleic acids after 8h of co-incubation. In addition, PCC-CDs exhibited comparable antibacterial activity to amoxicillin over this period. The antioxidant activity of PCC-CDs was also evaluated, revealing their excellent antioxidant properties. In conclusion, PCC-CDs demonstrate both strong antibacterial activity against C. perfringens and superior antioxidant capacity. This study presents a novel approach for the development and application of traditional Chinese medicine (TCM) resources, offers a theoretical foundation for future research on antibiotic alternatives, and lays the groundwork for innovative applications in natural products.

The effect of dietary zinc on growth performance, intestinal health and zinc metabolism of broilers under necrotic enteritis challenge

Potentials of Bacillus subtilis-derived surfactin to improve performance, intestinal health and welfare of broilers under necrotic enteritis challenge

Zinc improves meat quality by modulating lipid metabolism in necrotic enteritis challenged broilers

Toxoplasma gondii is an important apicomplexan parasite in veterinary medicine, with swine prevalence varying due to age, geographic distribution, and production program. Samples from a 6-wk-old pig from a small backyard farm with multisystemic disease concerns were submitted to the Iowa State University-Veterinary Diagnostic Laboratory. Gross findings included severe necrotizing enteritis with pseudomembrane formation and edematous, non-collapsing lungs. Histologic findings were severe necrotizing enterocolitis and random multifocal pulmonary and hepatic necrosis with numerous intralesional protozoal cysts consistent with T. gondii. Immunohistochemistry, reverse-transcription real-time PCR (RT-rtPCR), and serologic tests were positive for T. gondii; concurrent influenza A virus, porcine reproductive and respiratory syndrome virus, porcine circovirus 2, African swine fever virus, and classical swine fever virus were ruled out by RT-rtPCR. Given the worldwide distribution and zoonotic potential of T. gondii, the possibility of infection in swine should be considered.

Solid-state fermented Artemisia argyi residue improves immune response and intestinal integrity of broilers challenged with Clostridium perfringens.

ABSTRACTClostridium perfringens is a multi‐host opportunistic pathogen whose plasmid‐encoded toxins cause gas gangrene, necrotic enteritis and enterotoxemia, resulting in substantial economic losses in animal husbandry. In light of antibiotic bans and the need for alternatives, we employed reverse network pharmacology to screen and in vitro validate artemisinin (ART), then assessed its efficacy in murine and rabbit infection models challenged with C. perfringens type F. ART treatment did not significantly affect body weight change or intestinal histopathological damage. However, it significantly modulated inflammatory cytokines and antioxidant parameters in a tissue‐ and species‐dependent manner. Specifically, ART increased serum TNF‐α in mice, decreased IL‐1β in rabbits and elevated IL‐10 in multiple tissues. In addition, ART enhanced hepatic SOD and T‐AOC in mice and reduced hepatic MDA in rabbits. Microbiota analysis revealed limited and subtle shifts in community structure following ART intervention. Transcriptomic analysis further indicated that ART treatment induced marked changes in hepatic gene expression, particularly involving detoxification, lipid metabolism and stress response pathways, with notable species‐specific differences in enrichment profiles. While correlation analysis suggested associations of Anaerotruncus with hepatic detoxification genes and Bacteroides with inflammation‐regulatory genes, these genus‐level findings are based on correlation only and should be interpreted with caution given the lack of significant changes in overall microbial community structure. Collectively, these results indicate that ART can modulate host inflammatory and antioxidant responses, but its impact on gut microbiota composition in C. perfringens infection models appears limited, and the biological significance of observed genus‐level associations remains to be elucidated.

Group A Clostridium perfringens is a major poultry pathogen that causes necrotic enteritis. The molecular similarity of its toxins to those of other bacterial species suggests the involvement of horizontal gene transfer through mobile genetic elements or bacteriophages. Lysogenic bacteriophages play an important role in bacterial evolution through horizontal gene transfer. In the present study, we examined and compared the physiochemical characteristics, genome sequences, and tail fiber proteins of two lysogenic bacteriophages infecting C. perfringens. Bacteriophages ΦCP5(17) and ΦCP17(i) were isolated from a sewage sample and tested for their stability at different temperatures and pH conditions, and in simulated gastric fluids. The genomes of these phages were sequenced, and their morphology was examined by electron microscopy. Both phages produced circular, hazy plaques on their host bacteria and were stable up to 60°C, exhibiting optimal activity at pH 7-8. Both bacteriophages were found to have a very narrow host range, with ΦCP17(i) exhibiting a slightly broader host range than ΦCP5(17). Both phages exhibited podovirus morphology and a genome size of 17.8 kb and 17.9 kb for ΦCP5(17) and ΦCP17(i), respectively. According to the ICTV classification system, ΦCP5(17) and ΦCP17(i) belong to the genus Brucesealvirus, family Guelinviridae, and class Caudoviricetes. These phages share 95.6% genomic nucleotide sequence identity, suggesting that they belong to the same species but differ at the subspecies level. Although ΦCP5(17) and ΦCP17(i) have similar morphological and genomic features, their tail fiber proteins differ in their predicted folding patterns. Nucleotide sequence analysis indicated the absence of toxin and antibiotic resistance genes. Both phages encode a SpoVG protein, whose functional role requires further investigation.