ANÁLISIS DE LA EXPRESIÓN GLOBAL DE GENES EN LA MADURACIÓN SEXUAL PRECOZ EN LA CEPA LOCHY DE SALMÓN ATLÁNTICO Salmo salar

The Lochy strain of Atlantic Salmon, known for its rapid growth and short life cycle, faces the challenge of early maturity onset in males, in both freshwater and seawater environments. Despite control strategies, high rates of maturity continue to negatively impact fish farms productivity and animal welfare. Research into the genetic determinants of sexual maturity offers a promising approach to addressing the issue.

The current study compared the differential gene expression associated with precocious maturity between early maturing and immature male salmon from the Lochy strain. A custom microarray was used to examine gene expression in the brain, liver, and gonad of 22 salmons.

A total of 47,761 differentially expressed genes were identified, highlighting an intense transcriptomic response in the gonad (Figure 1a – 1c). Candidate genes to characterize the differences between immature and mature tissues were identified: in the brain of immature fish, various haptoglobins; in mature liver tissue, 17β-HSD3 and TCN1-like; in the immature gonad, rs3a and TCPP-like; and in the mature gonad, eif1b and skp1.

In the brain, genes related to hemoglobin capture, the innate immune system, and the transport of lipids were observed. In the liver and gonad, there were genes involved in oxidative stress, lipid metabolism, and steroid biosynthesis. Functional enrichment analyses revealed genes expressed in critical areas such as the immune system and metabolism. KEGG pathways were implicated in signal transduction, transport and cell growth. Finally, the study recognizes the genes vgll3 and chmp2ba, previously associated with precocious sexual maturity in this species, as related to the trait in this strain. Our findings provide a deep understanding of the transcriptomic mechanisms of maturity as a basis for targeted genetic improvement strategies.

This work was funded by the National Agency for Research and Development (ANID)/ Scholarship Program/ Doctorado Becas Chile/2021–21211159 and the collaboration of “Salmones Camanchaca”.