Protein and lipid uptake are important factors influencing survival
and performance of fish larvae. Whilst genes related to lipid
metabolism were not affected by the feeding of the carbohydrate b-glucan,
protease activity and associated gene expression was
enhanced in MacroGard® fed larvae. This is concordant with previous
observations that dietary b-glucan enhances trypsin activity
in red snapper (Lutjanus peru) . In the aforementioned study
the authors used a different b-glucan formulation (i.e. Fibrosel®)
compared to the present study, we therefore assume that the yeast
carbohydrate stimulated the digestive system and not any other
components of the feed additive. This increased peptidase activity
results in increased supply of amino acids to the organism [59],
which in turn enhances survival.