L-amino acids and their derivatives supplementation enhances growth and metabolic responses in Labeo catla (Hamilton, 1822)

Abstract

Improving feed intake is a key strategy for enhancing the production efficiency of the culture system. The present work was conducted to evaluate the efficiency of selected amino acids and their derivatives as feeding stimulants and attractants on growth and physio-biochemical parameters of Labeo catla. Four hundred and eighty (30.95±1.86 g) fish were distributed in a completely randomised design for a 60-day feeding trial. Eight iso-nitrogenous (30%) and iso-caloric (375 Kcal 100g–1) practical diets were formulated: control (no supplementation), Ala (1.5% supplemental alanine), Arg (1.25% supplemental arginine), Bet (0.5% supplemental betaine), Glu (1% supplemental glutamic acid), Gly (1% supplemental glycine), Hyp (1% supplemental hydroxyproline) and Lys (1.5% supplemental lysine). Dietary supplementation significantly (p < 0.05) improved feeding response, weight gain (WG), weight gain percentage (WG%), protein efficiency ratio (PER), average daily gain (ADG), and specific growth rate (SGR), with the highest growth performance observed in the Hyp group followed by Arg, Ala and Bet. The activities of digestive enzymes (amylase, protease and lipase) and metabolic enzymes (glucose-6-phosphate dehydrogenase, G6PDH, alanine aminotransferase, ALT; aspartate aminotransferase, AST) were significantly (p < 0.05) upregulated. Furthermore, supplemented diets elevated antioxidant enzyme profiles while reducing malate dehydrogenase and lactate dehydrogenase activity, indicating lower physiological stress. These findings demonstrate that functional amino acid addition in feed, particularly 1% hydroxyproline, 1.25% arginine, and 1.5% alanine, acts as an effective feeding stimulant. This offers a practical approach to formulate better feeds for L. catla.