International Journal of Marine Science, 2025, Vol.15, No.6, 303-312 http://www.aquapublisher.com/index.php/ijms 310 more likely to have problems when encountering stress (Visudtiphole et al., 2025). Therefore, regularly testing the nutritional components of feed and promptly adjusting the supply of amino acids, fatty acids and vitamins is a simple yet effective way to avoid nutritional health problems. 7.2 Application of prebiotics, immunostimulants, and plant extracts Adding functional additives to feed is an important means to improve the health level of farmed animals. Prebiotics, as the "nourishment" for probiotics, can promote the reproduction of beneficial bacteria in the intestines, improve the balance of the microbial community, and thereby enhance the digestive and absorptive capacity and disease resistance of farmed animals. For example, adding oligosaccharide substances to shrimp and fish feed can often increase the number of intestinal lactic acid bacteria and reduce the level of harmful bacteria (Abhiram et al., 2025). Immunostimulants directly activate the immune system of animals and enhance their non-specific immune responses. Commonly used substances of this kind include yeast polysaccharides, β -glucan, etc., which can enhance the activity of immune factors such as phagocytes and lysozyme, putting fish and shrimp in a better state of disease resistance. Plant extracts, as natural health-promoting additives, are also attracting increasing attention. Many Chinese herbal medicines (such as garlic, astragalus, etc.) contain antibacterial, antioxidant and immunomodulatory components. Appropriate addition can play the role of inhibiting bacteria, preventing diseases and enhancing physical fitness (Leyva-Lopez et al., 2020). The rational combined use of these additives can reduce the dosage of antibiotics, prevent the occurrence of diseases without harming the health of animals, and promote the development of the animal husbandry towards a greener and safer direction. 7.3 Oral vaccines, nanoparticle-based agents, and immune monitoring In actual operation, it is very difficult to administer vaccines to each fish or shrimp one by one, which is also the reason why oral vaccines are receiving increasing attention. Feeding animals with antigen packages in feed can induce a certain immune response and at least reduce the stress caused by the operation. However, oral vaccines also have weaknesses. Antigens are easily decomposed in the intestine. Therefore, researchers have begun to use carriers such as microcapsules and nanoparticles to protect antigens and improve absorption efficiency, thereby enhancing the immune effect (Jin et al., 2021). Similar nanotechnology is also used in antibacterial agents or immunomodulators, such as making plant extracts into nanoparticles to enhance their activity and duration of action. However, when using it, attention should also be paid to the dosage and potential environmental impact. At the same time, immune monitoring should not be ignored. Regularly measuring antibody titers, lysozyme activity and other indicators can help breeders determine earlier whether the animal's immunity has declined. If a downward trend in the immune status is detected, nutritional supply can be adjusted in advance, water quality improved or other interventions taken to prevent minor issues from escalating into large-scale diseases. Acknowledgments The authors thank Professor Li and the research team for their guidance and support during the writing of this paper, and also appreciates the reviewers' constructive comments. Conflict of Interest Disclosure The authors confirm that the study was conducted without any commercial or financial relationships and could be interpreted as a potential conflict of interest. References Abhiram A., Krishnan R., Ahalya A., Shaji S., Pillai D., Roshan R., and Safeena M., 2025, Development of oral vaccine using calcium phosphate nanoparticles conjugated with outer membrane protein of Aeromonas hydrophila in Oreochromis niloticus (Tilapia), Vaccine, 62: 127508. https://doi.org/10.1016/j.vaccine.2025.127508 Ashour M., Mabrouk M., Mansour A., Abdelhamid A., Kader M., Elokaby M., El-Nawsany M., Abdelwarith A., Younis E., Davies S., El‐Haroun E., and Naiel M., 2024, Impact of dietary administration of Arthrospira platensis free-lipid biomass on growth performance body composition redox status immune responses and some related genes of pacific whiteleg shrimp Litopenaeus vannamei, PLOS ONE, 19(6): e0300748. https://doi.org/10.1371/journal.pone.0300748 Bussabong P., Rairat T., Chuchird N., Keetanon A., Phansawat P., Cherdkeattipol K., Pichitkul P., and Kraitavin W., 2021, Effects of isoquinoline alkaloids from Macleaya cordata on growth performance survival immune response and resistance to Vibrio parahaemolyticus infection of Pacific white shrimp (Litopenaeus vannamei), PLoS ONE, 16(5): e0251343. https://doi.org/10.1371/journal.pone.0251343
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