Effects of Dietary L-Proline and L-Alanine on Growth Performance, and Flesh Quality of Common Carp (Cyprinus carpio) Juveniles

The purpose of the present study was to investigate the effects of amino acids L-proline and L-alanine on growth performance, amino acid, and fatty acid levels in the fillet of juvenile common carp. Four hundred and fifty juvenile common carp were randomly distributed in 30 tanks and fed with three levels of proline (5 [P5], 10 [P10], and 15 [P15] g/kg), three levels of alanine [A] (5 [A5], 10 [A10], and 15 [A15] g/kg), three levels of proline-alanine combination [PA] (2.5 + 2.5 [2.5PA], 5 + 5 [5PA], 7.5 + 7.5 [7.5PA] g/kg feed) and basal diet (control). The highest body weight gain (25.85 ± 0.1 g) and survival rate (91.11 ± 3.84) were observed in 7.5 PA treatment. The highest protein content (64.58 ± 0.49) was noticed in 2.5 PA; however, compared to combined treatments (5 PA and 2.5 PA), it did not show any significant difference (P<0.05). The highest total amount of essential amino acids (48.30 ± 48.3) was observed in 7.5 PA treatment. The highest amount of DHA (5.65 ± 0.08), total EPA, and DHA (8.91 ± 0.13) were in 7.5 PA treatment. Finally, it can be concluded that two amino acids L-proline and L-alanine at the combined level of 5 PA can improve the growth performance, survival, and fillet composition in the juvenile common carp.