Protein nutrition is always a prime area of research in aquaculture to develop sustainable aquafeeds. However, u nlike the essential amino acids (EAAs), the non-essential amino acids (NEAAs) did not get much importance in fish nutrition. Many studies support that NEAAs play multiple roles such as growth, stress response, cell signaling, larval metamorphosis, gut health, feeding stimulant and so on. Among NEAAs, L-alanine plays an important role in energy-budgeting and acts a major source of gluconeogenesis . In this study, L-alanine is used as promising additive to reduce the dietary fish oil inclusion.
A 2 × 6 factorial designs containing 12 diets (isonitrogenous : 42% crude protein) with two levels of lipid (L: 20 and 14%) and six levels of L-alanine (A: 0, 0.5, 1.5, 2.5, 3.5, and 4.5%) . A total of 576 rainbow trout juveniles (average weight: 12.4 ± 0.12 g) were randomly distributed in triplicates in 36 tanks and reared for five weeks in a recirculatory aquaculture system .
Dietary lipid level has significant effects on growth performance (Table 1). F ish fed low dietary lipid (14%) with 1.5-2.5% L-alanine (L14A1.5 and L14A2.5) exhibited similar (p>0.05) growth performance as control group (L20A0 : 20% lipid without L-alanine). There was no significant effects of different level of lipid and dose dependent L-alanine on feed conversion ratio (FCR) and protein efficiency ratio (PER). Neither dietary lipid level nor dose dependent L-alanine has significant effects on FCR and PER (Table 1). Final data for growth, feed utilization and gene expression pattern for amino acids transporters and lipid metabolism will be presented after nine weeks of feeding trial.
This is the first report where we have found that dietary dispensable amino acid L-alanine can be successfully used to reduce significant amount of oil in rainbow trout diet without affecting the growth performance . Outcome of this study will reduce the feed cost of salmonid aquaculture.