Full replacement of menhaden fish meal protein by low-gossypol cottonseed flour protein in the diet of juvenile black sea bass Centropristis striata

Authors: ANDERSON, AUSTIN - University Of North Carolina-Wilmington; ALAM, MD - University Of North Carolina-Wilmington; WATANABE, WADE - University Of North Carolina-Wilmington; CARROLL, PATRICK - University Of North Carolina-Wilmington; WEDEGAERTNER, THOMAS - Cotton, Inc; Dowd, Michael

Submitted to: Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2016
Publication Date: 8/5/2016
Citation: Anderson, A.D., Alam, M.S., Watanabe, W.O., Carroll, P.M., Wedegaertner, T.C., Dowd, M.K. 2016. Full replacement of menhaden fish meal protein by low-gossypol cottonseed flour protein in the diet of juvenile black sea bass Centropristis striata. Aquaculture. 464:618-628.

Interpretive Summary: Eight iso-nitrogeneous (46% crude protein) and iso-lipidic (14% crude lipid) diets were formulated and prepared to replace menhaden fish meal (FM) protein (59.5% CP) by low-gossypol glandless meal (GCSM) protein (50.4% CP), solvent-extracted cottonseed meal (SCSM) protein (53.8% protein) and high gossypol regular cottonseed meal (RCSM) protein (45% CP) for juvenile black sea bass Centropristis straita. Three diets replaced 50, 75, and 100% of FM protein by GCSM protein. Three other diets replaced 50, 75, and 100% FM protein by SCSM protein. One diet replaced 100% FM protein by RSCM protein. A control diet (0% CSM) was formulated with high FM protein and other practical protein sources. L-Methionine and L-lysine were supplemented to the diets to equal the control diet. Fifteen fish were stocked in each of twenty-four 75-L tanks, and each test diet was fed to triplicate groups of fish (mean initial weight = 7.7±0.1g) for 56 days under 22-24 C, 32-35 salinity, and ambient photoperiod conditions. Fish were fed twice per day (09:00 and 16:00 h) to apparent satiation. Final (day 56) mean body weight (BW, 24.16-31.62 g), body weight gain (BWG, 211.2-311.3%), specific growth rate (SGR, 1.70-2.18%/d), and feed intake (FI, 0.37-0.43 g/fish/d) were not significantly different (P < 0.05) among the control, GCSM, or SCSM treatments, but were markedly reduced (P < 0.05) in the 100% RCSM protein treatment (20.09 9, 159.5%, 1.45 %/d, and 0.25 g/fish/d). Lower palatability of the RCSM diet was attributable to the anti-nutrient compound gossypol. No significant differences in survival (84.1-97.8%), feed conversion ratio (1.05-1.33), protein efficiency ratio (1.62-2.08), or whole body protein or lipid composition were observed among the fish fed GCSM or SCSM diets. Gossypol content in the livers (25.9 mg/kg) was only detectable in fish fed the 100% RCSM diet. Fish whole body essential amino acid compositions did not differ significantly among treatments. Whole body n-3 PUFAs decreased, while n-6 PUFAs increased with increasing concentration of CSM protein in the diets. The apparent digestibility coefficient (ADC) of protein was relatively high (83.1-87.1%) among treatments. The results suggested that a maximum of 75% FM can be replaced with low gossypol solvent-extracted CSM protein, and 100% FM can be replaced with low gossypol glandless CSM protein in the diet of juvenile black sea bass with no adverse effects on survival, growth, and feed utilization.

Technical Abstract: Eight iso-nitrogeneous (46% crude protein) and iso-lipidic (14% crude lipid) diets were formulated and prepared to replace menhaden fish meal (FM) protein (59.5% CP) by low-gossypol glandless meal (GCSM) protein (50.4% CP), solvent-extracted cottonseed meal (SCSM) protein (53.8% protein) and high gossypol regular cottonseed meal (RCSM) protein (45% CP) for juvenile black sea bass Centropristis straita. Three diets replaced 50, 75, and 100% of FM protein by GCSM protein. Three other diets replaced 50, 75, and 100% FM protein by SCSM protein. One diet replaced 100% FM protein by RSCM protein. A control diet (0% CSM) was formulated with high FM protein and other practical protein sources. L-Methionine and L-lysine were supplemented to the diets to equal the control diet. Fifteen fish were stocked in each of twenty-four 75-L tanks, and each test diet was fed to triplicate groups of fish (mean initial weight = 7.7±0.1g) for 56 days under 22-24 C, 32-35 salinity, and ambient photoperiod conditions. Fish were fed twice per day (09:00 and 16:00 h) to apparent satiation. Final (day 56) mean body weight (BW, 24.16-31.62 g), body weight gain (BWG, 211.2-311.3%), specific growth rate (SGR, 1.70-2.18%/d), and feed intake (FI, 0.37-0.43 g/fish/d) were not significantly different (P < 0.05) among the control, GCSM, or SCSM treatments, but were markedly reduced (P < 0.05) in the 100% RCSM protein treatment (20.09 9, 159.5%, 1.45 %/d, and 0.25 g/fish/d). Lower palatability of the RCSM diet was attributable to the anti-nutrient compound gossypol. No significant differences in survival (84.1-97.8%), feed conversion ratio (1.05-1.33), protein efficiency ratio (1.62-2.08), or whole body protein or lipid composition were observed among the fish fed GCSM or SCSM diets. Gossypol content in the livers (25.9 mg/kg) was only detectable in fish fed the 100% RCSM diet. Fish whole body essential amino acid compositions did not differ significantly among treatments. Whole body n-3 PUFAs decreased, while n-6 PUFAs increased with increasing concentration of CSM protein in the diets. The apparent digestibility coefficient (ADC) of protein was relatively high (83.1-87.1%) among treatments. The results suggested that a maximum of 75% FM can be replaced with low gossypol solvent-extracted CSM protein, and 100% FM can be replaced with low gossypol glandless CSM protein in the diet of juvenile black sea bass with no adverse effects on survival, growth, and feed utilization.