|Green, Bartholomew - Bart|
|Rawles, Steven - Steve|
|GAYLORD, T. GIBSON - Us Fish And Wildlife Service|
|McEntire, Matthew - Matt|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/16/2018
Publication Date: 3/6/2019
Citation: Green, B.W., Rawles, S.D., Schrader, K.K., Gaylord, T.G., McEntire, M.E. 2019. Reducing dietary protein for hybrid tilapia reared in the biofloc production system affects fish performance and water quality dynamics[abstract]. Abstracts of Aquaculture 2019 meeting, New Orleans, LA. p. 419.
Technical Abstract: Given tilapia grown in the biofloc technology production system can consume the biofloc, it should be possible to optimize formulated diet protein content to account for nutrition derived from consuming biofloc. The present study, conducted in an outdoor, photoautotrophic-chemoautotrophic biofloc technology production system, evaluated impacts on fish production indices and water quality dynamics for hybrid tilapia (Oreochromis aureus x O. niloticus) fed diets supplemented with the first four limiting amino acids (Lys, Met, Thr, Ile) and formulated to the ideal protein profile (muscle) at 22.5% to 32.3% digestible protein (DP) and 6% lipid. Fingerlings (32.2 +/- 10.1 g/fish) were stocked in tanks (18.6 m2; 16.6 m3) in May 2016 at 25/m2 (29/m3) and grown for 5 months to market size. At harvest, fish fed the 22.5% DP diet were significantly smaller (518 g/fish) and had significantly higher feed conversion (1.5) than those fed the higher DP diets (553-564 g/fish and 1.4, respectively). Feed nitrogen input and nitrification rate increased linearly with increased DP. Results of this study suggest that by using ideal protein theory to formulate diets supplemented with the first four limiting amino acids (Lys, Met, Thr, Ile) digestible protein can be reduced from 32.3% to 27.7% without adversely affecting hybrid tilapia productivity indices. Market size distributions, nutrient retention, off-flavor, and pond water quality dynamics in relation to diet DP also are discussed.