IJMS2025v15n3

International Journal of Marine Science, 2025, Vol.15, No.3, 154-166 http://www.aquapublisher.com/index.php/ijms 157 are the primary factor: protein and fat content in the feed regulates the expression of digestive enzymes and growth factor genes. For example, under the conditions of providing high-quality baits (live sand silkworms, etc.), the genes related to energy supply in the female shrimp's ovaries are significantly upregulated, and the yolk protein and ecdysterone synthesis pathways are more active, which helps accelerate reproductive and growth processes (Awad et al., 2025). On the contrary, when malnutrition is present, shrimp may reduce metabolic rate by downregulating the IIS pathway gene and temporarily stop growing to maintain basic survival. Temperature is another important variable. Shrimps are warm-warming animals, and changes in water temperature will trigger a series of changes in gene expression of stress responses. When the ambient temperature is below the optimal growth temperature, the heat shock protein (HSP) gene is significantly upregulated in shrimp tissues to prevent protein denaturation damage. A study of the HSP gene family of Pacific white shrimp identified up to 76 HSP genes that showed diverse response patterns to different stressors. Among them, under low temperature stress, some HSP70 and HSP90 genes are strongly induced in tissues such as gills, hepatopancreas, and help the body restore homeostasis (Peng et al., 2016). Factors such as farming density and water quality will also affect shrimp growth through gene expression pathways. High-density farming can easily cause the accumulation of metabolic waste in water (such as ammonia nitrogen and nitrite). These stresses will trigger the expression changes of detoxification enzymes and immune factor-related genes, thereby allocating some energy for stress resistance rather than growth. In actual breeding, optimizing feed nutrition, controlling water temperature and reducing stress density are essentially creating environmental conditions conducive to the optimal expression of growth genes. Figure 1 Histological sections of muscles and total viable bacteria count after LvMEF2 interference. (A,C) control group(PBS); (B,D) dsMEF2group. The arrows in panel (B) refers to the region of nuclear agglutination (Adopted from Xia et al., 2023) 4 Functional Analysis of Reproduction-Related Genes 4.1 Ovarian/testicle development regulation genes and their expression dynamics The reproduction process of shrimps includes gonad development and maturation, gamete formation, and egg laying and hatching, and is finely regulated by a series of genes. In female shrimp ovaries, the most important nutrient supply protein is yolk protein (Vg), which is synthesized by the hepatopancreas and transported to the ovaries through blood and is ingested and utilized. The genes that regulate yolk protein synthesis and accumulation directly determine the quality and fertility of the egg. During ovarian maturation, the Vg gene expression increased significantly, while the expression of the yolk protein receptor (VgR) gene on the oocyte membrane was synchronously enhanced to promote yolk uptake (Li et al., 2022). As the ovaries enter a period of decline, the expression of these genes is rapidly downregulated, achieving renewal of the reproductive cycle. Related to egg formation are hormone synthetase genes such as ecdysterone (20E): Studies have found that during the oocyte development period, the 20E level increases, and the expression of its synthetic rate-limiting enzyme

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