Essential amino acid requirements of fish and crustaceans, a meta-analysis

A meta-analysis of literature data on essential amino acid (EAA) requirements of fish and crustaceans was performed to re-estimate EAA requirements and provide ideal amino acid profiles. Large numbers of studies have been conducted on EAA requirements of fish and crustaceans over the past decades. However, estimated EAA requirements of different species showed a large variation due to differences in methodological approaches and regression models. An extensive search and inclusion of literature on EAA requirements were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in this study, resulting in a dataset of 358 studies covering 77 species. The relative percentage of maximum weight gain was used as the outcome to evaluate the 10 EAA requirements. Forest plots analysis was employed for heterogeneity analysis, study weight allocation and re-estimation of the requirements. Results showed that trophic level, water temperature and dietary EAA inclusion levels affected EAA requirements estimation. The meta-analysis suggested that the estimated 10 EAA requirements (expressed as % crude protein, CP) of the fish were: arginine (Arg) 5.0 (+/- 0.14), histidine (His) 2.0 (+/- 0.11), isoleucine (Ile) 3.3 (+/- 0.16), leucine (Leu) 4.9 (+/- 0.24), valine (Val) 3.8 (+/- 0.11), lysine (Lys) 5.2 (+/- 0.12), sulfur amino acids (Met + Cys) 3.5 (+/- 0.18), total aromatic amino acids (Phe + Tyr) 6.2 (+/- 0.12), threonine (Thr) 3.5 (+/- 0.18) and tryptophan (Trp) 0.9 (+/- 0.08). Estimated EAA requirements (expressed as % CP) of crustaceans were Arg 5.1 (+/- 0.31), His 2.5 (+/- 0.15), Ile 4.3 (+/- 0.97), Leu 5.7 (+/- 0.08), Val 4.3 (+/- 0.30), Lys 4.9 (+/- 0.28), Met + Cys 3.2 (+/- 0.18), Phe + Tyr 5.1 (+/- 0.65), Thr 3.8 (+/- 0.04) and Trp 0.8 (+/- 0.15).