The protein level and proportion of animal protein in artificial diets for mullet, Mugil platanus

Abstract

The present research was carried out to determine the crude protein leveI and to evaluate the proportion of the animal protein in these diets, which promote the best growth rate for mullet, Mugil platanus. The rations utilized were isocaloric (3800 kcal of gross energy/kg of diet), in which the estimated levels of animal protein were 0%, 20% and 40% and the crude protein levels were 20% and 40%. After 72 days of observation, the average survival rate varied from 58 to 100%. The analysis of variance showed significative differences among the treatments, indicating that the diet composed with 40% of animal protein and 40% of crude protein promoted the best gain of average weight of the fishes. No significative correlation was observed between the gain in average weight and the average survival rate as well as between the gain in the average weight of the fingerlings and the daily average water temperature; average data of pH and the dissolved oxygen were correlated (P < 0.01) with the gain in average weight. The average survival rate did not present correlation with the average data of pH and the dissolved oxygen