Probiotics, as an alternative to antibiotics, are one of the better choices for ensuring product quality and food safety. Bacillus subtilis is often used in different forms, such as powder, granule, and liquid, in the livestock and poultry industry to produce feed and food additives and other products due to its advantages of high stability, low pathogenicity, high protein secretion capacity, and developed fermentation technology. This article reviews the biological characteristics, physiological functions, and effects on livestock and poultry production, as well as their mechanisms of action, to enhance the positive impact of the rational use of Bacillus subtilis as an additive in animal husbandry, such as feed and livestock food. In addition, this article also evaluates the potential of Bacillus subtilis to mitigate the negative effects of livestock and agricultural cultivation on the environment.

As science and technology continue to advance, the use of flow cytometry is becoming more widespread. It can provide important information about cells in the body by detecting and analysing them, thereby providing a reliable basis for disease diagnosis. In the diagnosis of bovine epidemic diseases, flow cytometry can be used to detect bovine viral diarrhoea, bovine leukaemia, bovine brucellosis, bovine tuberculosis, and other diseases. This paper describes the structure of a flow cytometer (liquid flow system, optical detection system, data storage and analysis system) and its working principles for rapid quantitative analysis and sorting of single cells or biological particles. Additionally, the research progress of flow cytometry in the diagnosis of bovine epidemic diseases was reviewed in order to provide a reference for future research and application of flow cytometry in the diagnosis of bovine epidemic diseases.