Seriola dumerili digestive capacity.

The greater amberjack, Seriola dumerili, is one of the marine species with the highest potential for aquaculture expansion in the Mediterranean, making the development of species-specific formulated feeds a priority. A complementary approach to evaluate the effect of feed formulation is to quantify the digestive capacity (DC) of the species, expressed as U fish-1, U organ-1, or U g-1 of tissue. This study characterizes the enzyme DC of S. dumerili (n = 5) under culture conditions. The difference between fish and the difference between means in each organ were intentionally evaluated to determine the distribution of the enzymatic DC. Somatic indices were stomach, 0.448 ± 0.156; pancreas (PAN), 0.605 ± 0.274; pyloric caeca (PC), 0.785 ± 0.298; and intestine: anterior (AI), 0.170 ± 0.067; mid (MI), 0.252 ± 0.145; and posterior (PI), 0.223 ± 0.074. PAN activity was considered a reserve DC. For an average fish weight of 1633.8 ± 654.9 g, total DC values (U/fish) were 101.66 ± 41.90 for acid protease, 189.08 ± 96.72 for alkaline protease, and 290.75 ± 136.24 U/fish for acid + alkaline protease. Amylase, lipase (triolein substrate), and total lipase using p-nitrophenyl myristate yielded 734.47 ± 352.83, 93.82 ± 2.35, and 311.64 ± 28.57 U/fish, respectively. Chymotrypsin and trypsin were 1091.1 ± 410.8 and 67.0 ± 36.4 U/fish, respectively (experimental chymotrypsin U/experimental trypsin U ratio of 16.3). Across all alkaline enzymes, the PC exhibited the highest DC when compared with AI, MI, or PI regions. Digestive capacity provides a biochemical basis for studies aimed at optimizing protein, starch-glycogen, and lipid levels in aquaculture feeds, considering the DC of protease, amylase, and lipase, as a tool for analyzing species' enzymatic-level responses.