|Rawles, Steven - Steve|
Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/24/2005
Publication Date: 9/7/2005
Citation: Gaylord, T.G., Rawles, S.D. 2005. The modification of poultry by-product meal for use in hybrid striped bass diets. Journal of the World Aquaculture Society. 36(3):365-376. Interpretive Summary: Fish have not grown well on diets containing high amounts of poultry by-product meal (PBM) because protein quality is usually poorer in PBM than in fish meal (FM). Protein quality is affected by the pattern of amino acids in that protein, as well as the availability of those amino acids to the fish. Animal nutritionists have often thought it might be more efficient to feed a diet that contained the same amino acid pattern found in that animal's own muscle. This is the ideal protein model. We tested whether all the FM protein typically fed to hybrid striped bass could be completely replaced with pet food grade PBM. First, we determined the pattern and availability of essential amino acids in menhaden FM and PBM to hybrid striped bass (HSB). Four amino acids were found to be critically low in PBM when its amino acid pattern was compared to that of hybrid striped bass muscle. In the second trial, we used the ideal protein model to add amino acids to test diets containing PBM. We fed groups of HSB one of six test diets containing the same amount of digestible protein (40%) from either FM (one diet), or PBM (one diet), or PBM with added amino acids (four diets) and then measured several indicators of growth and body composition. The amino acids that were added to the PBM diet were lysine (Lys), or Lys + methionine (Met), or Lys + Met + threonine (Thr), or Lys + Met + Thr + leucine (Leu). The amounts of amino acids added were based on the amounts needed to match the pattern of HSB muscle. Supplementing pet food grade PBM with at least Lys + Met resulted in growth and body composition that was comparable to that of fish fed the diet containing protein from fishmeal only. Therefore, a viable method exists whereby all fishmeal in diets for hybrid striped bass can be replaced with pet food grade poultry by-product meal.
Technical Abstract: A pair of experiments was performed to assess amino acid supplementation of pet food grade poultry by-product meal (PBM)for use as the sole protein source for hybrid striped bass (HSB). The first trial determined the amino acid availability from menhaden fishmeal and poultry by-product meal. The second trial determined the efficacy of supplementing PBM with amino acids based on an ideal profile of HSB muscle. The positive control (POS) diet contained 40% digestible protein from menhaden fishmeal (MFM)and the negative control (NEG) diet contained 40% digestible protein from pet food grade PBM. The NEG diet was additively supplemented with lys, met, thr, and leu at 1.16, 0.57, 0.31 and 0.47% of the diet, respectively. Lysine supplementation alone did not improve performance based on any measured response. The NEG diet and the lys diet had lower weight gain and feed efficiency than the POS diet. Supplementation with lys and met, lys, met, and thr, or lys, met, thr, and leu improved weight gain and feed efficiency above that of the NEG diet. The NEG diet supplemented with lys, met, and thr produced weight gains nearly equivalent to those of the POS diet. Protein and energy retention efficiencies improved with addition of at least lys and met and were nearly equal to those observed in fish fed the POS diet. Addition of lys and met reduced the hepatosomatic index to levels comparable to those in fish fed the POS diet. Intraperitoneal fat (IPF) levels were similar among treatments (6.1-6.6%) with the exception that fish fed the diet with added lys, met, and thr exhibited lower (5.5%) IPF. Supplementing with only lys and met increased muscle ratio to levels equivalent to those found in fish fed the fishmeal (POS) diet. In conclusion, amino acid supplementation of pet food grade PBM can be used to replace all fishmeal in diets for hybrid striped bass.