Growth performance and feeding costs of juvenile mullet subjected to feed restriction

The objective of this work was to evaluate the effect of restricted feeding on the growth and fed costs of juvenile mullet (Mugil liza). Five feeding levels 100, 80, 60, 40 e 20% satiation, named as F100%, F80%, F60%, F40% e F20% - were evaluated in triplicate. Juvenile mullets with 0.21+/-0.03 g (n=30) were randomly distributed in 15 tanks of 200 L. Cost estimation was done for the production of one thousand juvenile mullets. Survival was higher than 93%, and there was no influence of treatments. The specific growth rate of mullet in the F100% treatment was 5.96+/-0.18% per day, and the final weight was six-fold higher than the initial one. Mullets of the F20% treatment had the smallest liver somatic index, smallest hepatocytes and nuclei, and the smallest hepatic glycogen reserve, in comparison to fish of other treatments. The feeding level reduction hampered the juvenile mullet growth. However, a feeding level of about 72% satiation is capable of promoting a better utilization of the feed consumed, with 28% reduction of feed costs.