Leping Wang

Colibacillosis caused by avian pathogenic Escherichia coli (APEC) remains an important bacterial disease in poultry production and is increasingly difficult to control because of antimicrobial resistance. In this study, a lytic phage, ND-4, was isolated from poultry-farm sewage using the O2:K1 APEC strain IMT5155 as the host, and its biological characteristics, genome features and preliminary application potential were evaluated. ND-4 formed clear plaques on IMT5155 and showed a tailed morphology, with an elliptical head of 110 ± 5 nm by 82 ± 5 nm and a tail of 97 ± 5 nm by 18 ± 2 nm, giving a total virion length of approximately 204 ± 10 nm. The phage had an optimal multiplicity of infection of 0.01, a latent period of 20 min, a 50 min burst period and a burst size of 231 PFU/cell. ND-4 remained active across pH 4–9 and at temperatures up to 60 °C, and it retained titers above 10⁸ PFU/mL after exposure to chloroform concentrations up to 15%. Whole-genome sequencing revealed a 154,669 bp double-stranded DNA genome with 184 predicted open reading frames and a G + C content of 48.98%. No virulence or antimicrobial resistance genes were detected. ND-4 reduced biofilm biomass in vitro and decreased tissue bacterial loads and alleviated hepatic inflammation and vacuolar degeneration in IMT5155-challenged chicks. These results indicate that ND-4 is a promising candidate for further development as a phage-based control agent against APEC infection, although larger in vivo studies are needed to define its efficacy, dosing window and biosafety profile.

This study investigated the effects of composite postbiotic preparation on the growth performance, immune function, and microbiota composition of Nubian black goats. Thirty healthy Nubian black goats with similar body weights were randomly assigned to two groups (n = 15 per group): a control group fed a basal diet and a treatment group fed the basal diet supplemented with 0.5% composite postbiotic preparation (equal-ratio co-fermentation of Bacillus subtilis GX15 and Lentilactobacillus buchneri GX0328-6). The results indicated that while compound postbiotic supplementation did not significantly alter the average daily gain (ADG) and the serum biochemical indices (p > 0.05), it significantly increased the concentrations of immunoglobulins (IgG and IgA) compared to the control group (p < 0.05). Despite comparable α- and β-diversity, CPP supplementation selectively enriched Bacteroides, UCG-005, and Ruminococcaceae while reducing Turicibacter (LEfSe LDA > 2.0; STAMP p < 0.05), suggesting targeted modulation of gut microbiota. In conclusion, dietary supplementation with 0.5% composite postbiotic preparation improves immune function and modulates intestinal microbiota composition without significantly affecting growth performance in black goats while improving intestinal microbial composition and promoting overall gut health.

Zinc oxide promotes poultry growth, but it tends to agglomerate. This necessitates high doses and leads to environmental contamination from unabsorbed, excreted zinc. Undigested zinc is excreted and can enter the food chain, increasing the probability of zinc residues in edible poultry tissues (muscle, liver, and eggs) and raising concerns for consumer safety. MOF-supported single-atom zinc catalysts (SAC) resolve agglomeration by atomic anchoring, enhancing bioavailability. High-temperature/high-pressure fixation of Zn²⁺ surfaces was confirmed by XRD, while FESEM revealed the corresponding surface morphology, collectively verifying SAC formation. SAC exhibited potent antimicrobial efficacy against key pathogens such as Salmonella typhimurium, Escherichia coli, and Staphylococcus aureus (MIC of 3.125 mg/mL, MBC of 25 mg/mL). Co-culture experiments further demonstrated that the antibacterial performance of SAC remained stable over a temperature range of 20–80 °C and a pH range of 2–8, thus exhibiting excellent thermal stability and gastrointestinal tolerance. In 7-day-old chicks, SAC alleviated S. typhimurium-induced inflammation, reduced bacterial adherence, upregulated claudin-1, preserved gut homeostasis, ameliorated tissue lesions, and increased the abundance of Lactobacillus in the cecum, demonstrating promising potential for poultry infection control.

The global epidemic of bovine coronavirus (BCoV) has caused enormous economic losses. The characterisation and genetic composition of endemic strains in Southwest China remain elusive. This study aimed to fill this gap by isolating three BCoV strains from this region and sequencing their whole genomes. To elucidate the genetic evolution and characterisation of the prevalent strains, the results of BCoV sequences were compared in GenBank, with a focus on genetic evolution, mutation, and recombination patterns. The results showed close homology between strains NN190313 and NN230328, while strain NN221214 showed less similarity to these two strains but clustered with the French strain of the European branch. Intriguingly, NN190313 and NN230328 were grouped with goat-derived BCoV strains from Jiangsu Province in Eastern China in the Asian–American branch. In addition, recombination analyses revealed significant signals between NN230328 and either a Chinese goat-derived strain (XJCJ2301G) or a Shandong strain (ShX310). This study highlights the importance of monitoring cross-species transmission between cattle and goats, especially in the mountainous areas of Southwest China where mixed farming occurs, and thus, the monitoring of cross-species transmission between cattle and goats is important for preventing new public health challenges, providing important insights for research on cross-species transmission, early prevention, and control measures, with potential applications in vaccine development.

Salmonella Typhimurium (S. Typhimurium) contamination poses a significant challenge to breeder egg hatchability and chick health, necessitating the exploration of alternative disinfection methods. This study investigates the potential of phage vB_SPuM_SP02 (SP02) as a novel disinfectant for breeder eggs contaminated with S. Typhimurium SM022. Phage SP02 was isolated from poultry farm effluent and characterized for morphology, biological properties, and genome properties. Experimental groups of specific pathogen-free (SPF) eggs were treated with Salmonella and phage SP02, and efficacy was assessed through hatching rates, chick survival, weight, Salmonella load, immune organ indices, and intestinal flora. Phage treatment effectively eradicated Salmonella contamination on eggshells within 12 h, resulting in increased hatching and survival rates compared to controls. Furthermore, phage treatment mitigated weight loss and tissue Salmonella load in chicks without causing immune organ damage while reducing Salmonella spp. abundance in the intestinal tract. This study demonstrates the potential of phage SP02 as an eco-friendly and efficient disinfectant for S. Typhimurium-contaminated breeder eggs, offering promising prospects for practical application in poultry production.

Salmonellosis is a disease caused by non-typhoid Salmonella, and although some lactic acid bacteria strains have been shown previously to relieve Salmonellosis symptoms, little has been studied about the preventive mechanism of Lentilactobacillus buchneri (L. buchneri) against Salmonella infection in vivo. Therefore, the L. buchneri was fed to C57BL/6 mice for 10 days to build a protective system of mice to study its prevention and possible mechanisms. The results showed that L. buchneri GX0328-6 alleviated symptoms caused by Salmonella typhimurium infection among C57BL/6 mice, including low survival rate, weight loss, increase in immune organ index and hepatosplenomegaly, and modulated serum immunoglobulin levels and intrinsic immunity. Importantly, the L. buchneri GX0328-6 enhanced the mucosal barrier of the mouse jejunum by upregulating the expression of tight junction proteins such as ZO-1, occludins, and claudins-4 and improved absorptive capacity by increasing the length of mouse jejunal villus and the ratio of villus length to crypt depth and decreasing the crypt depth. L. buchneri GX0328-6 reduced the intestinal proliferation and invasion of Salmonella typhimurium by modulating the expression of antimicrobial peptides in the intestinal tract of mice, and reduced intestinal inflammation and systemic spread in mice by downregulating the expression of IL-6 and promoting the expression of IL-10. Furthermore, L. buchneri GX0328-6 increased the relative abundance of beneficial bacteria colonies and decreased the relative abundance of harmful bacteria in the cecum microflora by modulating the microflora in the cecum contents.

Escherichia coli (O78) is an avian pathogenic Escherichia coli (APEC). It can cause perihepatitis, pericarditis, septicemia and even systemic infections in the poultry industry. With the incidence of antibiotic resistance reaching a crisis point, it is important to find alternative treatments for multidrug-resistant infections. The use of phages to control pathogens is a promising therapeutic option for antibiotic replacement. In this study, we isolated a lytic phage called vB_EcoS_GN06 from sewage. It lysed APEC GXEC-N22. Transmission electron microscopy showed that the phage belongs to family Siphoviridae. Phage GN06 has a 107,237 bp linear double-stranded DNA genome with 39.2% GC content and 155 coding sequences. It belongs to the genus Tequintavirus, subfamily Markadamsvirinae. The multiplicity of infection of 0.01 and the one-step growth showed that the latent time is 60 min and the burst size is 434 PFU/cell. Temperature and pH stability tests showed that phage GN06 was stable in the range of 4 °C–60 °C and pH 5–9. GN06 showed significant inhibition of APEC both within the liquid medium and in biofilm formation. These results suggest that phage GN06 has the potential to control bacterial pathogens. Thus, GN06 has the potential to be a new potential candidate for phage therapy.

Food contamination by Salmonella can lead to serious foodborne diseases that constantly threaten public health. Innovative and effective strategies are needed to control foodborne pathogenic contamination since the incidence of foodborne diseases has increased gradually. In the present study, two broad-spectrum phages named Salmonella phage PSE-D1 and Salmonella phage PST-H1 were isolated from sewage in China. Phages PSE-D1 and PST-H1 were obtained by enrichment with Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) CVCC1806 and Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) CVCC3384, respectively. They were able to lyse Salmonella, E. coli and K. pneumoniae and exhibited broad host range. Further study demonstrated that PSE-D1 and PST-H1 showed high pH and thermal tolerances. Phage PSE-D1 belongs to the Jiaodavirus genus, Tevenvirinae subfamily, while phage PST-H1 belongs to the Jerseyvirus genus, Guernseyvirinae subfamily according to morphology and phylogeny. The results of genome analysis showed that PSE-D1 and PST-H1 lack virulence and drug-resistance genes. The effects of PSE-D1 and PST-H1 on controlling S. Enteritidis CVCC1806 and S. Typhimurium CVCC3384 contamination in three kinds of foods (eggshells, sausages and milk) were further investigated, respectively. Our results showed that, compared to phage-free groups, PSE-D1 and PST-H1 inhibited the growth of their host strain significantly. A significant reduction of host bacteria titers (1.5 and 1.9 log₁₀ CFU/sample, p < 0.001) on eggshells was observed under PSE-D1 and PST-H1 treatments, respectively. Furthermore, administration of PSE-D1 and PST-H1 decreased the counts of bacteria by 1.1 and 1.2 log₁₀ CFU/cm² (p < 0.001) in sausages as well as 1.5 and 1.8 log₁₀ CFU/mL (p < 0.001) in milk, respectively. Interesting, the bacteriostasis efficacy of both phages exhibited more significantly at 4 °C than that at 28 °C in eggshells and milk and sausages. In sum, the purpose of our research was evaluating the counteracting effect of phage PSE-D1 and PST-H1 on the spread of Salmonella on contaminated foods products. Our results suggested that these two phage-based biocontrol treatments are promising strategies for controlling pathogenic Salmonella contaminated food.