Dietary replacement of fishmeal with commercial protein blends designed for aquafeeds in hybrid striped bass (Morone chrysops × Morone saxatilis): Digestibility, growth, body composition, and nutrient retention

Authors: MCCANN, KATIE - University Of Arkansas At Pine Bluff; Rawles, Steven - Steve; LOCHMANN, REBECCA - University Of Arkansas At Pine Bluff; McEntire, Matthew - Matt; SEALEY, WENDY - Us Fish And Wildlife Service; GAYLORD, T. GIBSON - Us Fish And Wildlife Service; Webster, Carl

Submitted to: Aquaculture Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2021
Publication Date: 10/19/2021
Citation: Mccann, K.M., Rawles, S.D., Lochmann, R.T., Mcentire, M.E., Sealey, W.M., Gaylord, T., Webster, C.D. 2021. Dietary replacement of fishmeal with commercial protein blends designed for aquafeeds in hybrid striped bass (Morone chrysops × Morone saxatilis): Digestibility, growth, body composition, and nutrient retention. Aquaculture Reports. 21. Article 100903. https://doi.org/10.1016/j.aqrep.2021.100903.
DOI: https://doi.org/10.1016/j.aqrep.2021.100903

Interpretive Summary: As global fish meal supplies remain flat and commodity prices increase, cost effective and sustainable replacements for dietary fish meal must be found for the hybrid striped bass industry to remain competitive into the future. Four commercial protein blends Elite 60™, Elite 65™, Elite 70™, and Pro-Cision™ (HJ Baker & Bros., Inc., Tuscola, TX) were evaluated in hybrid striped bass for digestibility and fish meal replacement value. The commercial blends were proprietary mixes of sustainable animal and plant proteins targeted for aquaculture. A control diet was formulated containing 17% fish meal that met or exceeded nutritional requirements of hybrid striped bass. The commercial blends replaced fish meal in the control diet on a digestible protein basis and were balanced for nutrients. Generally, the fish meal control diet outperformed the other diets but the three Elite™ products performed intermediately, while the Pro-Cision™ diet lagged behind in both digestibility and growth performance. Therefore, Pro-Cision™ is not an attractive alternative to fish meal in hybrid striped bass diets considering cost, lower feed intake, growth, and nutrient retention. However, the Elite™ products may be potential fish meal replacements in hybrid striped bass diets due to lower cost in spite of slightly slower growth after 13-weeks. With some exceptions, digestibility of most nutrients in the commercial blends did not differ significantly from those of fish meal. In fact, protein was more digestible in Elite 70™ compared to that of fish meal. Some nutrients in the Pro-Cision™ test diet were less available than those of fish meal. Fish fed the Pro-Cision™ diet ate less feed, were smaller and had smaller fillets and more fat compared to fish fed the other commercial blends. Fish fed the Elite 70™ diet were most similar in performance to fish fed the fish meal control diet, but cost of this product is somewhat high, but lower than fish meal. The commercial blends did not negatively impact fish health as there were no differences in immune responses or other measures of fish health among fish fed the different blends compared to fish meal. These data support the use of the Elite™ protein blends as viable, sustainable alternatives to fish meal in hybrid striped bass feeds.

Technical Abstract: AFour commercial protein blends—Elite 60™, Elite 65™, Elite 70™, and Pro-Cision™ (HJ Baker & Bros., Inc., Tuscola, Texas, USA)—were evaluated in hybrid striped bass (HSB) for nutrient digestibility and fish meal (FM) replacement value. Test ingredients were proprietary mixes of animal and plant proteins targeted for aquaculture in developing nations where FM is scarce or nutritional profiles are inconsistent. A control diet was formulated like a commercial HSB feed containing 17% FM that met or exceeded the nutritional requirements of HSB. Commercial blends replaced FM in the control diets on an ideal protein basis by supplementing the first-three limiting amino acids (Met, Lys, Thr). Diets were formulated on a digestible protein basis (38% digestible protein), isolipidic (16%), and contained 10% lipid from marine fish sources. The FM control diet generally outperformed all other diets. The Elite™ products performed intermediate, while Pro-Cision™ lagged in both digestibility and growth responses. Digestibility of gross nutrients in each of the test products did not differ significantly from those of FM, but protein was significantly more digestible in Elite 70™ compared to that of FM and Pro-Cision™. Availabilities of Leu, Phe, Tyr, and Val in Pro-Cision™ were significantly less (92.2, 91.3, 91.0, and 91.5%, respectively) than those in FM (96.1, 96.8, 94.6, and 94.5%, respectively). Fish fed the Pro-Cision™ diet exhibited significantly lower cumulative feed intake, average weight, and muscle ratio compared to fish fed all other diets, while Elite 60™, Elite 65™, and Elite 70™ fish did not differ in intraperitoneal fat or muscle ratio compared to fish fed the FM control. Fish fed all three Elite™ diets had significantly lower average weight (52.5g - 57.9g) compared to fish fed the FM control (73.2 g).There were no differences in Arg and His whole-body nutrient retention among dietary treatments, while other nutrient retention efficiencies did differ across treatments. Nutrient retention of the averaged essential amino acids was not significantly different in fish fed Elite 70™ compared to fish fed the FM control. There were no significant differences in lysozyme activity, alternative complement activity, and mean corpuscular hemoglobin concentration among treatments. It appears that Pro-Cision™ is not an attractive alternative to FM in HSB diets considering cost ($2,700/ton), total feed intake, growth, and nutrient and energy retentions. However, Elite 60™ ($500/ton) and Elite 65™ ($610/ton) may be potential FM replacements in HSB diets despite differences in growth performance after 13-weeks.