Gene expression, growth and survival of European sea bass yolk-sac larvae (Dicentrarchus labrax) after PHB administration

To evaluate if the compound poly-ß-hydroxybutyrate (PHB) might be a suitable immunoprophylactic measure in fish larviculture, its capacity to improve immunity and performance in European sea bass (Dicentrarchus labrax) yolk-sac larvae was explored. Dietary PHB was applied from mouth opening onwards to stimulate the developing larval immune system at the earliest possible point in time.

Larval survival, growth, microbiota composition, gene expression profiles and disease resistance were assessed. PHB administration improved larval survival and, furthermore, altered the larva-associated microbiota composition. The bacterial challenge test using pathogenic Vibrio anguillarum revealed that the larval disease resistance was not influenced by PHB.