A new study has found that an extruded fishmeal-free diet results in higher weight gain and nutrient utilization in grass carp when compared with a pelleted diet.

The research group in China conducted the study to investigate the effects of extruded and pelleted feeds at various feeding rates on growth and nutrient utilization of grass carp (Ctenopharyngodon idellus).

Using the same fishmeal-free formula, they produced a pelleted feed and an extruded feed to administer to fish at feeding rates of 100%, 90%, 80% and 70% satiation. 

According to the study authors, “after 10  weeks of feeding, the fish fed pelleted and extruded feeds showed no differences in feed intake. At the same feeding rate, the fish fed extruded feed showed higher weight gain, protein retention efficiency, lipid retention efficiency and lower feed conversion ratio than those fed pelleted feed.”

Results also found that feeding to 80% satiation results in the lowest FCR and highest protein retention efficiency.

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