title: Accuracy of the use of energy conversion factors for compound fish diets.
abstract: Conversion factors of 23.6, 39.5 and 17.2 MJ/kg for protein, lipid and carbohydrate contents, respectively, are frequently used in fish studies to calculate the gross energy (GE) content of compound diets. Values predicted according to the above resulted in linear relationships of observed GE values with similar R (2) and mean prediction error (MPE) values when using either nitrogen-free extract (NFE) (R (2) = 0.5713, RMSE = 1.3134, MPE = 0.0741, n = 129, 32 studies) or starch (R (2) = 0.5665, RMSE = 1.6768, MPE = 0.0839, n = 190, 45 studies) as measurements of carbohydrate content. Apparent digestible carbohydrate content (either NFE or starch) was found to be linearly-related (R (2) values of 0.7531 and 0.7460, respectively) to its dietary content in compound fish diets. Predicted apparent digestible protein (ADP), lipid (DL) and carbohydrate contents, together with energy conversion factors, presented R (2) and MPE values of 0.6205 (RMSE = 1.2606) and 0.2051, respectively, between observed and predicted apparent digestible energy (ADE) content with NFE as measurement of carbohydrate content (n = 97, 17 studies, eight fish species). However, with carbohydrates quantified by starch content, an R (2) value of 0.7017 (RMSE = 1.7556) and MPE of 0.1055 were obtained (n = 37, 10 studies, five fish species).
authors.affiliation: a Research Institute of Fish Culture and Hydrobiology, University of South Bohemia , Vodnany , Czech Republic.
authors.forename: James
authors.initials: J
authors.lastname: Sales
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D017756:Aquaculture / Q000379:methods*; D003291:Conversion Disorder; D004032:Diet / Q000662:veterinary*; D004734:Energy Metabolism; D005399:Fishes / Q000378:metabolism*; D010827:Physiology / Q000379:methods*
keywords: carbohydrates; compound feeds; energy conversion; fish farming; lipids; prediction; protein