World Aquaculture Society Meetings

REDUCING DEPENDENCE ON FISHMEAL WITH ALTERNATIVE PLANT PROTEIN SOURCES IN THE DIETS OF SCIAENID SPECIES FOR ENHANCED AQUACULTURAL PRODUCTION

Sergio Castillo, Christian Minjarez, Mayra Gonzales, Martin Perez and Delbert M. Gatlin III
 
Department of Wildlife and Fisheries Sciences
Texas A&M University, College Station, TX 77843
sergio_sca@tamu.edu

Aquaculture now supplies over half of the total seafood consumed by humans. As aquaculture production has grown, so has the demand for fishmeal to include in cultured fish diets due to its excellent nutritional value. In order for aquaculture production to continue to expand in a sustainable manner, suitable alternatives to the finite and costly supply of fishmeal must be developed. One such group of alternative protein feedstuffs is derived from various plant products. One goal of this project was to extend the application of promising plant protein feedstuffs in place of fishmeal in the diet of red drum (Sciaenops ocellatus), a euryhaline sciaenid native to the Gulf and Atlantic coasts of the United States. This carnivorous species is extensively cultured along both coasts for stock enhancement and seafood production purposes, and has traditionally been fed fishmeal-based diets. In addition, red drum was used as a model for developing alternative-protein diets for the shortfin corvina (Cynoscion parvipinnis), a related sciaenid species which supports a commercial fishery in the Gulf of California and is being evaluated as a candidate for aquaculture at the University of Sonora and other institutions in Mexico.

Two parallel feeding trials were conducted under standardized conditions in indoor tanks operated as closed-recirculating systems to determine the responses of the sciaenids red drum (initially weighing 4.7 ± 0.3 g) and shortfin corvina (initially weighing 8.6 ± 1.0 g) to increasing dietary percentages of non-genetically modified soybean meal (Navita Premium Feed Ingredients, SBM-1030), soybean protein concentrate (Soy-PC) and corn protein concentrate (Corn-PC) as replacements for fishmeal. A basal, control diet was formulated to contain (dry-matter basis) 40% crude protein from fishmeal and 10% crude fat primarily from menhaden fish oil. Then, nine experimental diets were formulated by replacing 25%, 50% and 75% of protein in the control diet with SBM-1030, Soy-PC and Corn-PC.

Significant differences (P<0.05) were detected at the end of the feeding trials across all growth performance and feed utilization parameters, as evaluated by final weight gain, relative weight gain, daily weight increment, feed efficiency ratio, protein efficiency ratio and protein retention, for both red drum and shortfin corvina. The whole- body proximate composition of shortfin corvina was significantly influenced by the dietary treatments, but it remained unaffected in red drum. Results of the present study indicate that, for red drum, SBM-3010 and Soy-PC can replace up to 75% of fishmeal, and that Corn-PC can successfully replace up to 50% of fishmeal without compromising fish performance. For juvenile shortfin corvina, Soy-PC and Corn-PC can replace up to 75% of fishmeal protein in the diet, while SBM-3010 successfully replaced up to 50% of fishmeal protein without compromising fish performance. Although there are no preceding studies regarding the nutrition of shortfin corvina, the growth and feed efficiency responses to the different dietary treatments were similar to those found in red drum. This confirms that previous nutritional research done with red drum could be applied as a basis for the development of artificial diets to support the aquaculture programs for shortfin corvina. Therefore, this study provided an excellent opportunity to conduct comparative nutrition research and advance the development of more sustainable diets for the aquaculture of sciaenid species.

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