Digestible lysine requirement for Tambaqui (Colossoma macropomum) juveniles using the diet dilution technique

Abstract

This study aimed at determine the digestible lysine requirement of tambaqui juveniles using the diet dilution technique. A total of 250 juveniles tambaqui with an initial mean of 22.99 ± 1.06 g were used in a dose-response experiment with five levels of digestible lysine (0.865, 1.125, 1.383, 1.644 and 1.903%) and five replication per treatment. The digestible lysine levels evaluated did not influence the feed intake (P > 0.05), but there was a linear effect (P < 0.05) on the digestible lysine intake. Quadratic effects on weight gain, specific growth rate, feed conversion ratio, and body protein deposition were observed, estimating the requirements at 1.39; 1.37; 1.37 and 1.58% digestible lysine, respectively. Since there was no effect on the feed intake and, consequently, on energy consumption, the improvements in feed conversion ratio and weight gain occurred owing to the better amino acid balance of the rations in the requirement of digestible lysine. The requirement for digestible lysine in the diet for tambaqui juveniles was determined at 1.58% by the body protein deposition, which corresponds to 5.76% dietary crude protein.

Keywords

• Essential amino acid
• Zootechnical performance
• Amino acid requirement
• Fish nutrition
• Amazon fish