Open AccessDietary methionine requirement of juvenile Arctic charr Salvelinus alpinus (L.)
Author(s) -
Nancy B. Simmons,
Moccia,
Bureau,
Sivak,
Herbert
Publication year - 1999
Publication title -
aquaculture nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.941
H-Index - 79
eISSN - 1365-2095
pISSN - 1353-5773
DOI - 10.1046/j.1365-2095.1999.00097.x
Subject(s) - methionine , biology , salvelinus , juvenile , zoology , arctic , biochemistry , amino acid , ecology , fishery , trout , fish <actinopterygii>
The dietary methionine requirement of juvenile Arctic charr Salvelinus alpinus (L.) was assessed by feeding diets supplemented with graded levels of DL‐methionine (9, 12, 15, 18, 21, and 24 g kg −1 dietary protein) for 16 weeks at 12°C. All diets contained 400 g kg −1 protein, 170 g kg −1 lipid, 66 g kg −1 ash and an estimated 17.5 MJ digestible energy (DE) kg −1 . When live‐weight gain was examined using quadratic regression, the estimate of methionine requirement for optimal growth was 17.6 g kg −1 of dietary protein (DP) or 7 g kg −1 of the diet. Requirements estimated on the basis of carcass protein and energy gains were 18.8 and 17.9 g kg −1 DP, respectively. Plasma methionine concentrations and ocular focal length variability measurements did not provide a sensitive measure of requirement, because each responded in a linear fashion to increasing dietary methionine levels. Based on the prevalence of cataracts, the methionine level required to prevent lens pathology (26.7 g kg −1 DP) appears to be higher than that required for maximum growth.