Title: Growth, nutrient utilization, and digestibility of soy products by Florida pompano (Trachinotus carolinus) Author
Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only
Publication Acceptance Date: November 6, 2007
Publication Date: February 9, 2008
Citation: Riche, M.A. 2008. Growth, nutrient utilization, and digestibility of soy products by Florida pompano (Trachinotus carolinus) [abstract]. Book of Abstracts Aquaculture America. p. 436. Technical Abstract: The apparent nutrient digestibilities of 3 plant-based alternative proteins were determined during an 8 week digestibility study of juvenile pompano. Two 4X4 Latin square experiments were conducted within four 60L tanks on two separate recirculating systems. For both experiments, a menhaden meal-based formulation meeting the known protein and energy requirements for pompano served as the reference diet. In both saltwater (30 g/L) and low salinity (3 g/L) systems 3 plant protein sources were substituted (300 g/kg) for the reference diet (700 g/kg). The substituted feed ingredients were as follows: soybean meal (SBM), soy protein isolate (SPI), and corn-gluten meal (CGM). All diets included the addition of yttrium oxide (0.5% of diet) as an inert marker. Following acclimation, 10-15 pompano were stocked into individual units where an experimental diet was assigned for Week 1. Fish were fed 2X daily (5%BW) for 7 days before diets were rotated. Fecal samples were collected on Day 5 and 7. Samples were pooled and freeze-dried for analysis. Samples were evaluated for crude protein (CP) and energy. The evaluation of yttrium allowed the calculation of apparent digestibility coefficients (ADC). Results of the digestibility trial suggest SBM and SPI have a significantly higher ADC for CP than CGM in both the saltwater (SBM: 87.1, SPI: 85.0, and CGM: 83.4) and low salinity (SBM: 92.2, SPI: 93.1, and CGM: 81.9) systems. SPI exhibited a significantly higher ADC (88.3) for energy than SBM (64.3) or CGM (72.2). The availabilities of individual amino acids were also determined and will be presented. A separate 8 week fish meal replacement trial was conducted to determine the effects of graded substitution of SBM or SPI in a practical type diet on growth, efficiency, and nutrient utilization. Tanks were randomly assigned an experimental diet at a select inclusion level (0, 20, 40, 60, 80, and 100). Diets were formulated as isonitrogenous (44% crude protein) and isoenergetic (22 MJ/kg dry diet). Two separate recirculating systems with 24 tanks per system were used for this trial. Approximately 1000 juvenile pompano were acclimated to 3 g/L salinity and stocked at a density of 20 fish per tank. Fish were batch weighed before stocking and reweighed every two weeks till the end of the trial. Whole body proximate analysis and nutrient efficiencies will be presented. Preliminary growth results suggest that SPI can be successfully substituted for fish meal up to 40%. SBM is more tolerated by the pompano and seem to sustain growth at 80% substitution of fish meal.