Potential of invasive carp as a source of fish meal and fish oil in Channel Catfish diets

ABSTRACT Objective Invasive carp, a name encompassing Black Carp Mylopharyngodon piceus, Silver Carp Hypophthalmichthys molitrix, Bighead Carp H. nobilis, and Grass Carp Ctenopharyngodon idella, are outcompeting native fish and causing environmental instability in the lower Mississippi River basin. Harvest by commercial fishers is the most cost-effective management strategy. However, low demand and dockside prices have reduced incentives for commercial fishers to target invasive carp, reducing annual harvest numbers. Currently, the aquaculture industry relies on fish meal and fish oil from marine fish species, such as Atlantic Menhaden Brevoortia tyrannus, as important ingredients for many diets. However, as the industry continues to grow, demand for these marine fish will surpass availability. Methods In this study, we assessed the performance of invasive carp fish meal (ICFM) and invasive carp fish oil (ICFO) as feed ingredients for Channel Catfish Ictalurus punctatus. Graded levels of ICFM and ICFO (Aquatic Protein LLC, Beardstown, Illinois) were incorporated into starter diets. The diets were formulated on a 35% crude protein, 6% fat basis and designed to meet the amino acid requirements of Channel Catfish. In two 8-week feeding trials, ICFM was used to replace Atlantic Menhaden fish meal (MFM) or all plant and animal protein sources (MFM, soybean meal, corn protein concentrate; trial 1) and ICFO was used to replace 50% or 100% of the Atlantic Menhaden fish oil (trial 2). During these feeding trials, triplicate tanks of Channel Catfish were fed one of six treatment diets and growth, feed intake, feed efficiency, proximate composition, and protein and energy retention efficiency were assessed. Terminal measurements were also used to calculate values for condition factor, viscerosomatic index, and muscle ratio. Results There were no significant differences in the growth performance or composition of Channel Catfish when ICFM was included as up to 47% of the diet dry weight. Replacing plant and animal protein with ICFM enhanced energy retention efficiency relative to a diet where ICFM replaced only MFM. Similarly, growth performance was maintained when ICFO was used in place of 100% of MFM. This suggests that ICFM and ICFO are suitable alternative ingredients in Channel Catfish starter diets. Conclusions Invasive carp products offer suitable ingredient alternatives that can be used in starter diets for farmed Channel Catfish. This has the potential to enhance market demand for invasive carp, thereby benefiting fisheries and local economies, improving conservation and invasive species management in the Mississippi River basin, and enhancing the overall sustainability of aquaculture.