Maternal Stress Effects on the Expression of Growth-Related Genes in Early Developmental Stages of Brook Trout (Salvelinus fontinalis)

Maternal effects can have a strong impact on offspring growth and survival in fish. Maternal factors, such as mRNA, proteins, and hormones, are deposited in oocytes during sexual maturation. Stressed females produce eggs with higher levels of glucocorticoid hormones, which play key roles in the stress response and are known to have wide-ranging developmental effects in fish and other vertebrates; these effects include growth. However, the molecular mechanisms involved are not well understood. Our objective is to reveal the mechanisms through which maternal stress may impact growth regulation during early development in brook trout (Salvelinus fontinalis). We incubated and sampled offspring from four treatments: 1) control females, 2) females chronically stressed with weekly manipulations, 3) females fed with cortisol-enriched feed, and 4) unstressed females whose eggs were immersed in a cortisol solution for three hours prior to fertilization. The expression of genes related to growth (gh, ghr, igf-1, igf-1r) and the stress response (gr) during early development (eyed-stage, hatching, exogenous feeding) for each treatment will be presented.