EFFECT OF ENVIRONMENTAL FACTORS ON HERITABILITY AND ITS BIOMETRICS OF ARTEMIA FRANCISCANA VINH CHAU BY MASS SELECTION OF SMALL SIZED CYSTS

摘要

Artemia and rotifers are the most widely used live prey in aquaculture, and a lot of efforts have been made to replace rotifers by Artemia nauplii at first-feeding of shrimp, marine fish, and crab, but prey size limitations resulting in reduced larvalsurvival is still the main challenge (Baylon et al., 2004; Nhu et al., 2009; Watkins and Le Vay (2011)). Small-sized Artemia cysts by truncated selection is probably both a cost and nutritionally effective option to meet this demand. However, environmental effects and food availability were reported as playing an important role in Artemia growth and reproduction (Baert et al., 1997; Ann et al., 2009); and consequently might influence gametes. Browne et al. (2002), studying Artemia reproductive and lifespan traits confirmed that the environmental component contributes more to total phenotypic variation than the genetic one. This has been demonstrated for Artemia cyst size as well, which has been documented as negatively correlated with salinity and temperature of salt ponds during the reproduction phase (Guermazi et al., 2009). To assess the interference of environmental factors - i.e., food quantity, culture temperature, and salinity of the parental generation in the selection process, quantified as selection response R and heritability h2 - a factorial experiment was set up to select for small-sized cysts over two successive generations in laboratory conditions.