Dietary role of dispensable amino acids (DAA) in fish nutrition is not well studied. DAAs play important role in growth, cell signaling, gut health. Among DAAs, L-alanine helps in energy-budgeting and acts as a major precursor for gluconeogenesis. Therefore, aim of this study was to determine the use L-alanine to reduce the fish oil inclusion in the diet of rainbow trout.
A factorial design (2 × 6) consisting of twelve isonitrogenous diets (42% crude protein) containing two levels of lipid (L: 14 and 20%) and six incremental levels of L-alanine (A: 0, 0.5, 1.5, 2.5, 3.5, and 4.5%). A total of 576 fish (12.4 g) were stocked in triplicates in 36 tanks of recirculating aquaculture system and fed for nine weeks.
Results revealed that lipid and L-alanine levels have significant effect on growth performance. Dietary supplementation of 2.5% L-alanine in low lipid diet improved the growth compared to control (figure 1). Feed efficiency and protein utilization were improved by supplementation of 1.5 and 2.5% L-alanine (table 1). Interaction on lipid and L-alanine levels was observed for PER, indicates 2.5% L-alanine with lower lipid fed group showed high PER as compared to other groups. Lower lipid fed groups showed significantly lower IPF than high lipid fed groups. Additionally, amino acid metabolism enzymes (GOT and GPT) in serum were significantly affected by dietary lipid and L-alanine levels. Nutritional profile of fish fillet, gene expression pattern for protein and energy metabolism and hepatic metabolomics are being analyzed.
Based on our knowledge this is the first study wherein fish oil inclusion was reduced by using L-alanine as a source of energy in rainbow trout diet without compromising the growth.