Effect of different diets on body mineral content, growth, and survival of barbel, Barbus barbus (L.), larvae under controlled conditions

The experiment tested three formulated dry diets at 25°C to determine their effects on larval Barbus barbus (L.) body mineral composition, growth, and survival. Live Artemia nauplii were fed to all the larvae for the first 5 days of the experiment. From day 6 to day 25 inclusive, nauplii were the reference diet in one group, whereas the three other groups were fed dry diets exclusively. On D1 the fish body comprised 6.71% ash, 1.20% P, 0.35% Ca, and 0.09% Mg (dry matter), but initial feeding with nauplii resulted in increased values of all these components. The highest statistically significant (P 0.05) final body ash and mineral content was recorded for larvae fed nauplii (ash 13.22%; P 2.04%; Ca 2.95% and Mg 0.15%; d.m.). Fish fed nauplii grew faster than those fed dry diets (final mean BW 214.5 mg and 84.3-118.9 mg, respectively; all differences significant), and their final survival rate was also significantly the highest (99.9% and 96.5-99.4%, respectively). As evidenced by the current results, even short-term (20 days) feeding exclusively dry formulated diets can lead to considerable deficiencies in essential minerals in the larval body.