Prediction of digestible protein and lipid contents of crustacean feeds

Abstract

Due to distinctive feeding habits and digestive physiology determination of nutrient digestibility is more demanding with crustacean than fish species. A study was conducted to validate the use of linear prediction equations established with fish species to predict apparent digestible protein (ADP) and lipid (DL) contents [g kg−1 dry matter (DM)] of feed ingredients (ADP = −10.0731 + 0.8942 CP, DL = −1.5824 + 0.8654 CL) and compound diets (ADP = −51.4001 + 0.9872 CP, DL = −2.7303 + 0.9123 CL) from dietary crude protein (CP) and lipid (CL) contents for crustaceans (shrimp, lobster, crab). Observed values (n = 91) obtained in 17 studies, which evaluated CP digestibility of 26 feed ingredients for eight crustacean species, presented a linear relationship (R2 = 0.9213, RMSE = 54.1245) with predicted values. Predicted values overestimated observed values with a mean prediction error (MPE) of 0.1315. However, observed DL values of 17 feed ingredients (n = 31; studies = 5; species = 5) were overestimated with a MPE of 0.4500. Similar trends than above were found with prediction of the ADP (n = 185; studies = 32; species = 11; R2 = 0.8047; MPE = 0.1002) and DL (n = 64; studies = 11; species = 3; R2 = 0.6907; MPE = 0.2372) contents of compound diets.