Effects of dietary protein-energy ratio on the growth and body composition of the white mullet Mugil curema (Valenciennes, 1836) (Pisces: Mugilidae)

Abstract

The white mullet (Mugil curema) is an important resources exploited by coastal artisanal fishing in the Mexican Central Pacific. There is still not enough information about its nutritional requirements, in particular the appropriate protein-energy ratio of the diet, which has a significant influence on health and growth. The present study aimed to determine the protein-energy ratio of inert diets associated with greater growth in juveniles of M. curema under captive conditions. Eight experimental diets with different concentrations of proteins and lipids (P/L, %) were designed: 35/8, 40/8, 45/8, 50/8, 35/12, 40/12, 45/12, 50/12. Eight juveniles of M. curema, with an average weight of 5.7 ± 2.0 g and 7.9 ± 0.9 cm in length, were randomly placed in 24 experimental units of 0.5 m2 each to evaluate the eight diets in triplicate. The fish were fed to satiety three times a day for 60 days. Growth parameters, diet digestibility and survival rate were measured for each treatment to determine the protein-lipid ratio with the best effect on growth. Results suggest that 40% crude protein and 8% crude fat promote adequate growth in juveniles of M. curema. Higher levels of protein and/or lipids tend to generate a negative effect on growth.