LAUSR

Abstract The heritability of fatty acid composition of the Whiteleg shrimp Litopenaeus vannamei has not yet been evaluated. Highly unsaturated fatty acids (HUFA), particularly EPA, DHA, and ARA, provide structural and physiological stability to cells and tissues, playing a substantial role in stress response and immune system. Thus, genetic improvement for these characteristics would be possible if the heritability for HUFA is relevant. The purpose of the present study was to estimate genetic parameters for growth and the proportion of several fatty acids relative to their content in hemolymph of this species. Progeny from 79 full-sib families were reared under a common environment until they reached an average size of 22 g. Individuals were sampled (n = 674) for muscle tissue and hemolymph for DNA and fatty acid analyses, respectively. Parentage assignment of juveniles was done by genetic exclusion tests, using a 76-loci SNPs panel. Heritability was estimated for growth and for fatty acid percentage of 20 fatty acids and related measurements (n = 532). Intermediate heritability for growth (h2 = 0.42 ± 0.09) was estimated for the first time in this species in a mixed family reared design assisted with DNA parentage assignment. Limited heritabilities for fatty acids were estimated; nevertheless, some important fatty acids, such as EPA and DHA, proved to have significant variance among families with heritability values of 0.07 ± 0.05 and 0.12 ± 0.06, respectively. In contrast, ARA, which is tightly linked to the immune response, showed a value not significantly different from zero (