The present study was conducted to assess the efficacy of Laboratory-Isolated Lactocaseibacillus casei NK1 (Lc. NK1) in broilers hypothesizing that, Lc. NK1 supplementation will enhance growth performance, modulate the gut microbiome, and reduce fecal pathogenic Escherichia coli in broilers. The experiment spanned 35 days where 60 one-day-old broiler chicks were randomly assigned to four treatment groups (n = 15); control-group with no treatment (NC), APEC (challenged with E. coli only), CProb (received commercial probiotics), and LNK1 (treated with Lc. NK1). The APEC, CProb, and LNK1 groups were infected with E. coli O78 strain at 11 days of age. Growth performance analysis revealed that the LNK1 group by day 35 gained body weight similar to the CProb group, with both groups significantly outperforming the APEC group (p < 0.001). Both the LNK1 and CProp groups exhibited similar reduction in E. coli while increasing Lactobacillus colorizations in the cloacal swabs from day 21 to 35 of age (p > 0.05). Metagenomic analysis using 16S rRNA sequencing showed that the LNK1 group maintained a diverse and balanced gut microbiota, characterized by increased Firmicutes and reduced Proteobacteria. In contrast, the APEC group exhibited reduced diversity and dominance of Escherichia-Shigella (p < 0.001). These findings suggest Lc. NK1 could be a promising probiotic for enhancing gut health and growth performance in broilers, even under pathogenic challenges, offering a potential alternative to antibiotics in poultry production.

Bovine brucellosis, caused by Brucella abortus, is an economically significant bacterial disease causing enormous economic losses in developing countries. Due to emerging antibacterial resistance in current use of antibiotics and insufficient immunity by WHO recommended vaccine strategies, it is recommended to cull the positive animals to control the disease. In such circumstances, use of host specific bacteriophages could be an alternate option to control the disease. In present study, brucellaphages were isolated from slurry samples (n=50) of livestock farms. Seven samples were found positive in spot method, while two samples gave the positive plaques of pinpoint size (0.5 mm) with round and clear appearance in plaque assay. Isolated brucellaphages (BaP1 and BaP2) did not produce plaques against Staphylococcus aureus, Streptococcus, Bacillus, Escherichia coli, Salmonella, and Pasteurella multocida. Physicochemical characterization revealed that lytic activity of phages was present up to 60oC which started to decrease at 70oC and maximum stability was between 7 to 9 pH. Exposure of sunlight, normal fluorescent and UV light inactivated these phages within 3 hours, 24 hours and 15 minutes, respectively. Phages become inactivated in 15 minutes when treated with Sodium Dodecyl Sulphate, chloroform, Lysozyme, Proteinase K and EDTA, however, no effect of normal saline, Trypsin and RNAse was observed on brucellaphages. In conclusion, the results have laid the foundation to standardize practical applications of brucellaphages after detailed in-vitro and in-vivo experimental evaluations. Keywords: Brucellosis, Brucella abortus, brucellaphage, plaque assay, physicochemical characterization

Background and Objectives: Salmonella Enteritidis is widespread in the world and is known to be among the most com- mon agents of zoonotic food-borne illnesses. This study evaluates the efficacy of a bacteriophage cocktail — comprising SEPL01 (Siphovirus) and SEPL13 and SEPL20 (Myoviruses) — in controlling Salmonella Enteritidis infection in poultry. Materials and Methods: A total of 168 one-day-old desi chicks were procured and randomly divided into five different groups: negative control, positive control, prophylactic, 6 h and delayed post-challenge treatment group. Birds in the positive control and trial groups were orally infected with 10⁵ CFU/ml S. Enteritidis on the fourth day. The bacteriophage was given in 10⁷ PFU/ml through oral gavage, drinkers and aerosol spray. Bacterial enumeration was done using dilution plate counting on XLD agar and bacterial reduction was determined using log10 reduction. Results: Among the groups, the prophylactic group showed the highest log₁₀ bacterial reduction: 1.92 (Day 3), 1.79 (Day 7), and 1.23 (Day 14). Drinking water administration resulted in a log₁₀ reduction of 1.62, 1.44, and 0.91, respectively, while aerosol spray was the least effective with a log₁₀ reduction of 1.12, 0.85, and 0.52 across the same days. The treatment group receiving therapy 6 hours post-challenge exhibited a moderate level of reduction: 1.63, 1.37, and 1.22 via oral gavage; 1.43, 1.15, and 0.94 via drinkers; and 0.46, 0.15, and 0.12 via aerosol spray. The delayed post-challenge group showed smaller reductions: 1.56, 1.24, and 0.92 by oral gavage; 1.25, 0.99, and 0.79 by water; and 0.42, 0.13, and 0.10 by aerosol spray. Conclusion: The bacteriophage therapy is highly effective in reducing Salmonella Enteritidis, demonstrating potential as an antibiotic alternative.

Polyketide synthases type I (PKS-I) gene cluster is responsible for the synthesis of highly assorted group of secondary metabolites such as antimicrobial and anticancer agents. In our study, screening was carried out using degenerate primers to determine the presence of PKS-I gene cluster in endophytic actinomycetes isolated from two medicinal plants Ocmium teniflorum (Tulsi) and Azadirachta indica (Neem). A total of 28 endophytes that were isolated and identified from our previous study were further confirmed through 16S rRNA gene sequencing to exhibit a 99% similarity with Streptomyces sp. The molecular screening using PCR revealed the presence of PKS- I gene with a product size of 750bps in the isolates, FHK-1, FHK-2, FHK-3, FHK-4, FHK-5, FHK-6, FHK-7, FHK-8, FHK-9, FHK-11, FHK-13, FHK-16, FHK-18, FHK-20, FHK-21, FHK-23, FHK,25 and FHK-28. These isolates were further checked for their antimicrobial potential using their crude extracts. They displayed prominent bioactivity against ATCC pathogens, Escherichia coli, Proteus vulgaris, Rhodococcus equi, Staphylococcus epidermidis, Enterococcus faecalis, and Acinetobacter baumanii. Our study revealed that the endophytes from O. tenuiflorum and A. indica are bioactive and versatile harboring the PKS-I gene cluster.

The assurance of poultry meat quality and safety is a paramount concern for public health and trade. Pathogenic microorganisms, notably Salmonella enteritidis, jeopardize meat quality, necessitating effective interventions. This study investigated the antimicrobial efficacy of citric acid, garlic extract, and oregano seeds in reducing Salmonella enteritidis counts on chicken meat. Notably, Salmonella enteritidis is a leading foodborne pathogen associated with poultry products, contributing to substantial global gastroenteritis cases and fatalities. The emergence of drug-resistant strains due to indiscriminate antibiotic use underscores the urgency for viable alternatives. Spices such as garlic, oregano, and citric acid have gained attention for their potential antibacterial properties. In this research, comprehensive analyses were conducted on the effectiveness of these natural antimicrobial agents. Citric acid exhibited substantial inhibition zones at varying concentrations, leading to complete reductions in Salmonella enteritidis counts on chicken meat over different time intervals. Similarly, garlic extract demonstrated significant reductions in bacterial counts, with concentrations of 50%, 75%, and 100% exhibiting promising results. Oregano seeds' hexane extract also displayed potent antimicrobial properties, completely eradicating initial Salmonella enteritidis counts. Furthermore, the combined treatment of citric acid and garlic extract showcased synergistic antimicrobial activity. These findings underscore the potential of natural agents in enhancing food safety and quality by effectively reducing bacterial contamination in poultry products. The study contributes valuable insights into sustainable approaches for countering microbial threats in the food supply chain, ultimately ensuring consumer health and well-being