Evaluation of various cottonseed products on the growth and digestibility performance in Florida pompano Trachinotus carolinus

Two 10-week growth trials and digestibility trials were conducted to assess the efficacy of various cottonseed products in practical diets for the Florida pompano Trachinotus carolinus. In trial 1, a basal diet containing 150 g/kg of fishmeal (FM150) was modified by the iso-nitrogenous replacement of fishmeal (FM) with cold pressed cottonseed flour (CSF) resulting in diets containing 100 g/kg (FM100), 50 g/kg (FM50) and 0 g/kg (FM0) of fishmeal. To determine if lysine was limiting in the FM0 diet, two additional diets were developed using a high lysine corn protein concentrate (FM0-LCPC) or a crystalline source of lysine (FM0-CL). In trial 2, the basal diet was formulated to contain 457.0 g/kg of soybean meal (SBM) and 150 g/kg of poultry by-product meal (PBM), the other three diets were made by replacing SBM on an iso-nitrogenous and iso-lipidic basis with varying cottonseed flours (CSF) which included cottonseed flour (CSF), gossypol-extracted cottonseed flour (ECSF), and glandless cottonseed flour (GCSF). In trial 1, results showed that the use of up to 196 g/kg of CSF with a lysine supplement does not inhibit growth performance of the fish. In trial 2, no significant differences were observed in growth performance of the fish maintained on the various diets. Although gossypol was detected in the livers of fish offered diets with gossypol, no differences were observed in the cells of the liver samples or organization of the liver cells amongst any of the treatments. After each growth trial, apparent digestibility coefficients for dry matter (ADMD), energy (AED), and protein (APD) were determined for primary ingredients. In the first digestibility trial, no significant differences were observed with regard to digestibility coefficients for FM, CSF, and corn protein concentrate (CPC). In the second digestibility trial, no significant differences were observed on ADMD and AED for the ingredients GCSF, CSF, and ECSF. However, the APD values for ECSF were found to be significantly lower than those values of GCSF and CSF. Results of this study provide support that cottonseed products are acceptable for use in practical diets for Florida pompano. Statement of relevance: In this study, we assessed the efficacy of various cottonseed products in practical diets for the Florida pompano. These findings will be useful because the feed producers need the growth and digestibility data of the cottonseed products as an alternative ingredient to use in the diet formulation. The conclusions in this manuscript provide valuable information which researchers and feed producers need to use the cottonseed products in diets of this species. (C) 2015 Published by Elsevier B.V.