Ideal Protein-Based Estimation of Essential Amino Acid Requirements and The Role of Lysine Supplementation in Low-Protein Feed Formulations of Abalone.

BACKGROUND

High dietary protein levels in aquafeeds lead to increased nitrogenous waste, which requires the development of sustainable feeding strategies that balance growth performance with environmental responsibility.

OBJECTIVES

This study calculated the ratio of essential amino acids to lysine and investigated whether dietary protein could be reduced in feeds for Lvpan abalone (♀ × ♂) by lysine supplementation.

METHODS

Five diets were formulated to be isoenergetic: a control diet (CP27, 27% crude protein), 2 low-protein diets (CP23 and CP19, 23% and 19% CP, respectively), and their lysine supplementation counterparts (CP23 + AA and CP19 + AA). After an 84-d feeding trial (initial abalone weight, 19.49 ± 0.52 g), the growth, digestibility, nitrogen excretion, hepatic transaminases, muscle composition, water-holding capacity, texture, and volatile profile were measured.

RESULTS

The CP23 + AA diet maintained growth performance, improved apparent protein digestibility, and decreased nitrogen excretion compared with the control ( < 0.05). In contrast, the CP19 + AA diet reduced growth ( < 0.05). Lysine supplementation in the CP23 + AA group resulted in an increase in transaminase activity compared with the CP23 group, but it was not statistically significant ( > 0.05). Transaminase activity was greater in the CP19 + AA group than in the unsupplemented CP19 group ( < 0.05).

CONCLUSIONS

A 4% reduction in dietary protein, when supplemented with lysine, demonstrates potential for sustainable abalone aquaculture through sustained growth and product quality coupled with reduced nitrogenous waste production.