Analysis of Florida Pompano Trachinotus carolinus performance when fed practical diets of increasing levels of cotton seed flour processed by varying methods

Abstract

Florida pompano is a propitious species for marine aquaculture, and high demand has made the development of practical feed formulations essential. The cost of feed can be reduced by alternative plant protein sources such as cottonseed meal or flour. Albeit this is a cost effective protein source, the presence of gossypol in the meal can cause adverse health affects and limits the level of inclusion. Selective breeding and/or processing methods designed to reduce the total gossypol content could be utilized to improve the quality of the product and allow high inclusion levels. In order to assess the effects of cottonseed meal and gossypol content on Florida pompano two growth studies were performed. The first trial compared the effects of increasing inclusion of traditional cottonseed meal and need for lysine supplementation, while the second compared the effects of three cottonseed products and their resulting gossypol levels. The first growth trial showed that use of up to 19.6% cottonseed flour with a lysine supplement does not inhibit growth performance of the fish and is an acceptable protein source. The second growth trial showed that diets containing genetically low gossypol cottonseed flour resulted in significantly higher final mean weights and percent weight gains of than fish diets formulated using traditional cottonseed flour or gossypol-extracted flour. All diets are comparable to the soybean meal reference diet with respect to mean final weight and percent weight gain of fish, FCR and survival. Following each trial, The digestibility of the primary protein sources were evaluated to provide basic data on digestibility coefficients. In the first trial, fishmeal, cottonseed meal, and corn gluten meal showed no significant difference as primary ingredients in regard to mean apparent dry matter digestibility (ADMD), mean apparent protein digestibility (APD), or mean apparent energy digestibility (AED). No significant difference between the mean apparent digestibility coefficients (ADC) values for cottonseed meal, extracted cottonseed meal, and glandless cottonseed meal diets were found with respect to ADMD for ingredients (ADMDI) and AEDI. However; ethanol (EtOH) extracted cottonseed flour was found to be significantly lower in apparent protein digestibility of the ingredient APD. These results provide support that cottonseed flour, especially that of a genetically low gossypol variety, is acceptable to use in feed for Florida Pompano. Diets including any of these primary ingredients show comparable performance and digestibility to fishmeal-based diets.