Md Roisul Momen

The increasing prevalence of antimicrobial resistance (AMR), growing concerns regarding antimicrobial residues, and restrictions on the use of antibiotic growth promoters have intensified the search for safe and sustainable alternatives in animal production. Among the diverse probiotic microorganisms investigated for this purpose, Bacillus species have attracted particular attention because of their endospore-forming capacity, resistance to processing and gastrointestinal stresses, and broad range of functional activities. This review summarizes recent trends in the application of Bacillus-based probiotics across animal production systems, with emphasis on their mechanisms of action, functional benefits, technological advances, challenges, and future prospects. Species including Bacillus subtilis, B. licheniformis, B. amyloliquefaciens, B. coagulans, and B. clausii have been investigated in poultry, swine, ruminants, aquaculture, insects, and companion animals, with reported effects on intestinal microbial homeostasis, nutrient digestion and utilization, immune modulation, pathogen suppression, intestinal barrier integrity, and production performance. Recent advances in genomics, metagenomics, microbiome research, synbiotic formulations, encapsulation technologies, and precision livestock farming are expanding opportunities for strain-specific selection and targeted probiotic application. Evidence from experimental and production studies indicates that appropriately selected Bacillus strains can improve growth performance, feed efficiency, nutrient utilization, disease resistance, and selected environmental outcomes while potentially reducing dependence on conventional antimicrobial interventions. Nevertheless, substantial challenges remain, particularly regarding strain-specific efficacy, safety and genomic characterization, consistency under commercial conditions, formulation, dose optimization, and regulatory harmonization. Overall, Bacillus-based probiotics represent a promising multifunctional approach for supporting animal health and productivity and contributing to more sustainable and antimicrobial-responsible animal production systems. Asian Australas. J. Biosci. Biotechnol. 2026, 11(3), 65-82

Crossbreeding with Holstein Friesian (HF) cattle has become a widely adopted strategy for improving dairy productivity in Bangladesh. However, limited information is available regarding the optimum level of HF genetic contribution that maximizes milk production while maintaining disease resilience in crossbred cattle under smallholder farming conditions. This study evaluated the relationship between HF blood percentage, lactation milk yield, and the incidence of common livestock diseases in F1 and F2 crossbred cattle. It was hypothesized that increasing HF genetic contribution would improve milk yield without significantly affecting the occurrence of major diseases. Data were collected from 1,694 crossbred cattle (847 F1 and 847 F2) maintained by marginal farmers across 27 districts of Bangladesh from May, 2022 to October, 2024. Animals were classified according to HF sire blood percentage. Lactation milk yield and the occurrence of Foot-and-Mouth Disease, Hemorrhagic Septicemia, mastitis, reproductive tract disorders, and dystocia were evaluated. One-way ANOVA, Kruskal–Wallis H test, and Pearson's Chi-square test were used to determine the effects of HF blood percentage on productive performance and disease incidence. HF blood percentage had a highly significant effect on lactation milk yield in both F1 and F2 generations (P < 0.001). Crossbred cattle with 93.75% HF blood consistently achieved the highest milk yield in both generations, whereas milk production generally declined with increasing local genetic inheritance. Breed upgradation speed also influenced productive performance, with fast and very fast upgradation producing higher mean lactation yields than normal and moderate upgradation. In contrast, no significant association was observed between HF blood percentage and the incidence of the investigated diseases (P = 0.614), indicating that disease occurrence was largely independent of genetic composition. HF genetic contribution improves milk production, whereas disease susceptibility is influenced primarily by non-genetic factors. Strategic crossbreeding and proper management are essential for sustainable dairy production. The findings support sustainable dairy breeding programmes that combine genetic improvement with effective management to enhance milk production while maintaining the adaptability of crossbred cattle. Asian Australas. J. Biosci. Biotechnol. 2026, 11(2), 22-35

Antimicrobial residues in food products of animal origin represent a significant public health concern that requires careful consideration due to their harmful effects on consumer health. The presence of antibiotic residues in animal-derived food poses challenges for international trade involving animals and their products. Public health issues related to antibiotic residues in food include the emergence and spread of antimicrobial resistance (AMR), allergic reactions, cancer risks, genetic mutations, birth defects, bone marrow damage, and disruption of normal gut microbiota. The indiscriminate use of antibiotics in livestock can lead to residue levels that exceed permissible limits, resulting in adverse health effects for humans. Limiting antibiotic use is crucial for the safety of animal products. This review examines the administration of antibiotics to food animals, the presence of antibiotic residues in animal-origin foods, and the various factors that influence these residue levels in animal-derived food products in developing countries. It underscores the urgent need for improved regulatory control and surveillance of antibiotic use in food-producing animals to ensure public health safety. The findings highlight the importance of strengthening residue monitoring systems, enforcing withdrawal periods, and promoting responsible antibiotic stewardship to reduce contamination in animal-derived foods. Asian Australas. J. Biosci. Biotechnol. 2025, 10(3), 64-76

Demand for quick meals, such as ready-to-cook (RTC) foods, has been rising among modern consumers due to changing lifestyles worldwide, including in Bangladesh. However, these foods have been linked to several foodborne diseases, posing a significant threat to public health. As a result, assessing the microbial quality of RTC food products has become essential. This study aimed to evaluate the microbial quality of commonly available chicken-based RTC frozen foods in the markets of Mymensingh city. A total of 50 samples from five distinct types, collected from various retail points, were analyzed for total counts of aerobic bacteria, Staphylococcus spp., and Enterococcus spp., to determine how these loads compare against established safety standards. Correlations between different microbial loads were also examined. Generally, high levels of contamination were observed in almost all samples, except for low enterococcus counts in spring rolls. The mean counts of aerobic plate count (APC), total staphylococci count (TSC), and total enterococci count (TEC) across different food types ranged from 4.56 to 7.14 log CFU/g, 1.30 to 6.14 log CFU/g, and 1.24 to 3.56 log CFU/g, respectively. Two items, samosa and sausage, were identified as the most unsatisfactory in terms of microbial quality. Food manufacturers and regulatory authorities should focus on reducing contamination risks and regularly monitoring the food production chain. Consumers should also carefully follow cooking instructions and, if possible, avoid high-risk products. These findings underscore the need for strengthened hygiene practices, stricter regulatory monitoring, and improved quality control measures to ensure safer production and distribution of RTC chicken products in Bangladesh. Asian Australas. J. Food Saf. Secur. 2025, 9(2), 47-56

Crossbreeding in dairy cattle has recently become of increased interest. However, there is limited knowledge regarding the impact of crossbreeding on both the physical attributes and milk production capacity of crossbred cattle in Bangladesh. Data from 847 crossbred Holstein cattle were used to estimate the genetic effects on average milk yield. Besides, the history of 5 certain disease conditions was also collected. F1 and F2 generations were categorized by the percentage of sire blood they had and then the data were analyzed to find the point at which genetic contribution leads to the most productivity. The mean production and impact of breeding sires’ blood percentage were measured through statistical tests like ANOVA, Chi-square and Kruskal-Wallis tests. The result showed that in both F1 and F2 generations, maximum lactation yield was found in 0.9375% Holstein Friesian sires’ blood group (1265.3333 ± 15.36436 L and 1597.1803 ± 217.02733 L respectively). For the two generations, the results indicate a highly significant effect of blood percentage on overall milk production, though certain diseases were not significantly associated. The results also revealed that as the amount of local breed blood increased, the amount of milk produced consistently decreased indicating the importance of keeping the amount of exotic blood between 75% and 93.75%. In conclusion, productive performance of crossbred cattle relies heavily on strategic breeding programs and the fast crossbreeding had a thoughtful impact on milk production in the study area.