The Relationship between the Expression of Fatty Acyl Desaturase 2 () Gene in Peripheral Blood Cells (PBCs) and Liver in Gilthead Seabream, Broodstock Fed a Low n-3 LC-PUFA Diet.

The principle aim of this study is to elucidate the relationship between the fatty acid desaturase 2 gene () expression pattern in peripheral blood cells (PBCs) and liver of gilthead seabream (GSB), broodstock in order to determine the possible use of expression as a potential biomarker for the selection of broodstock. This selection could be utilized for breeding programs aiming to improve reproduction, health, and nutritional status. Passive Integrated Transponder (PIT)-tagged GSB broodstock (Male-1.22 ± 0.20 kg; 44.8 ± 2 cm and female-2.36 ± 0.64 kg; 55.1 cm) were fed a diet containing low levels of fish meal and fish oil (EPA 2.5; DHA 1.7 and n-3 LC-PUFA 4.6% TFA) for one month. After the feeding period, expression in PBCs and liver of both male and female broodstock were highly significantly correlated (r = 0.89; < 0.001). Additionally, in male broodstock, liver expression was significantly correlated ( < 0.05) to liver contents in 16:0 (r = 0.95; = 0.04) and total saturates (r = 0.97; = 0.03) as well as to 20:3n-6/20:2n-6 (r = 0.98; = 0.02) a Fads2 product/precursor ratio. Overall, we found a positive and significant correlation between expression levels in the PBCs and liver of GSB broodstock. PBCs expression levels indicate a strong potential for utilization as a non-invasive method to select animals having increased fatty acid bioconversion capability, better able to deal with diets free of fish meal and fish oil.