Immunity?is an important indicator of aquatic animals' ability to resist pathogenic microorganisms, maintain their health status, and adapt to environmental changes.
The immune system can effectively recognize, attack, and eliminate invading pathogens, thereby reducing the risk of developing diseases. To some extent, it can self-resist pathogens and reduce dependence on drugs.
Currently, lysozyme (LZM) and alkaline phosphatase (AKP) are commonly used as markers in research to indicate animal immunity.
- CHEN et al. found that increasing bile acid levels increased the activity of LZM and AKP in abalone serum. At the same time, adding bile acids to the feed can prevent nuclear factor kappa B (NF - κ B) translocation, downregulate the expression of tumor necrosis factor - α (TNF - α) and activator protein-1 (AP-1), thereby reducing the inflammatory response of abalone digestive glands. Cytokines play an important role in regulating the inflammatory response and immune function of aquatic animals, including interleukin-1 β (IL-1 β), TNF - α, interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), and transforming growth factor - β (TGF - β).
- YAO et al. constructed a high plant protein feeding model for carp and found that in the control group, there was an increase in intrinsic layer inflammatory mucin, goblet cell failure, and inflammatory vacuolar cells. After supplementing bile acids, the intrinsic layer mucin signal decreased, the gene expression of inflammatory cytokines [TNF - α, IL-1 β, transforming growth factor beta 1 (TGF - β 1), and IL-10] decreased, and pathological symptoms were significantly alleviated, indicating that bile acids can alleviate intestinal inflammation and lesions.
- WANG et al. found that adding bile acids to tongue sole feed significantly upregulated the expression level of TGF - β 1 in the liver, while significantly decreasing the expression levels of TNF - α and IL-8, indicating accelerated wound healing and reduced tissue damage in tongue sole liver, as well as reduced inflammatory response.
- XIA et al. found that the expression levels of pro-inflammatory genes IL-6 and anti-inflammatory genes [IL-10, TGF - β, and macrophage galectin (MGL)] in largemouth black bass increased in the 0.03% bile acid addition group, while the expression levels of IL-6 and arginase (ARG) decreased in the 0.45% bile acid addition group, indicating that adding an appropriate amount of bile acid can alleviate intestinal inflammation.
