A new study has found that including citric acid in diets for juvenile turbot (Scophthalmus maximus) can improve the bioavailability of phosphorus (P).

The research group from China conducted the 12 week feeding trial to investigate the suitability of citric acid as a feed additive to reduce P excretion. They compared two control diets with two diets containing citric acid supplements (1.5% and 3.0%). 

Compared with the control group, the pH of stomach contents in the group fed the diet containing 3% citric acid supplement was significantly lower and the pepsin activity and digestibility of P were notably higher.

\"Compared to both control diets, citric acid supplemented diets significantly increased the activity of pepsin,\"  stated the study. \"In summary, dietary inclusion of 3% citric acid markedly improved the bioavailability of P, without compromising intestinal function and health of fish. Citric acid seemed to be a promising feed additive for aqua-feeds to reduce P discharge into environment.\"

This article includes excerpts from the study abstract, published in the Journal of Aquaculture