Animal Molecular Breeding, 2025, Vol.15, No.2, 91-101 http://animalscipublisher.com/index.php/amb 94 Channa maculata, a total of 51 important SNP loci associated with growth traits such as body weight and body length were identified, among which the HS6ST1 gene was closely associated with traits such as body weight, body length, and total length (Liu et al., 2024). Other candidate genes are related to biological processes such as organelle formation, signal transduction, cell proliferation, and muscle growth, providing a theoretical basis for marker-assisted selection in breeding programs. Growth-related traits in Channa maculata showed moderate to high heritability, with most traits estimated to be between 0.22 and 0.52, all of which were moderate to highly heritable, and only one trait had a heritability of 0.108 1 (Liu et al., 2024). This result shows that it is feasible to improve feed conversion efficiency and growth performance through selective breeding, and it is expected to achieve genetic progress in artificially domesticated populations. The all-male NBS produced based on sex control and hybrid breeding has a feed conversion rate (FCR) that is 12.5%-17.6% lower than that of mixed-sex NBS and 72.3% lower than that of purebred Channa. Moreover, the proportion of individuals weighing more than 1 kg reached 91.3%-96.4%, which was significantly higher than that of the control group (Ou et al., 2021), indicating that it also has great potential in growth efficiency and economic benefits. 3.2 Reproductive traits and sex differentiation inChanna Channa spp. show a wealth of molecular regulatory mechanisms in the mechanism of sex differentiation, such as the sex-specific expression of genes such as Foxl2, Amh, and Cyp19a1a, which are affected by epigenetic regulation. In Channa argus, the Foxl2 gene is strongly expressed in the ovary during the early stage of gonadal differentiation, indicating that it plays a key role in female differentiation (Wang et al., 2015). Similarly, in C. argus, the expression of the Amh gene in male testes is significantly higher than that in females, with XY males expressing 36.03 times (P<0.01) 90 days after hatching, while females remain at a low level; after treatment with estrogen, the expression of Amh in XY sex-changed females is downregulated to a level similar to that of XX females (Luo et al., 2020). A high-density genetic linkage map constructed in Channa maculata revealed major loci closely related to sex determination. A single major locus located on linkage group 2 (LG2) explains almost all the variation in trait expression, indicating that its sex determination mechanism conforms to the XX/XY chromosome system. This discovery provides a genetic basis for regulating sexual maturity and developing sex-controlled breeding strategies (Liu et al., 2021). In this sex-linked region, the study identified four markers that are heterozygous in males and homozygous in females, and also verified a sex-specific SNP marker that can be used for actual sex identification. 3.3 Stress resistance and immunity inChanna strains Channa have strong environmental adaptability, and their immune systems show rhythmic regulation, stress response to pollutants, and positive immune response to nutritional intervention. In the study of Channa punctatus, it was found that the phagocytosis, superoxide anion production, and nitrite release of immune cells (such as macrophages and lymphocytes) in its head kidney and spleen showed obvious annual rhythms, and immune function peaked from October to March, suggesting that fish adapt to seasonal stress through immune rhythms (Chandra et al., 2023). Verma et al. (2015) found that after Channa punctata consumed a diet containing 5% fig and acacia plant powder, its serum superoxide dismutase (SOD), nitrate, nitric oxide and phagocytic activity increased, and its immunoglobulin content also increased, enhancing its resistance to A. hydrophila. Another study found that after Channa argus consumed a diet containing 50-100 mg/kg astaxanthin, the activity of antioxidant enzymes (SOD, CAT, GSH-Px) increased, the expression of pro-inflammatory factors (TNF-α, IL-1β) decreased, and the survival rate against A. hydrophila increased to 58% (Li et al., 2019).
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