Growth Performance of Largemouth Bass Fed Fish Meal Derived from Asian Carp

Feeds for carnivorous fish like Largemouth Bass Micropterus salmoides are commonly based on marine-origin fish meal, but this ingredient is costly. Fish meal derived from undesirable species, such as invasive Asian carp Hypophthalmichthys spp., is a promising alternative source of protein for carnivorous fish, but information regarding its biological value as a feed ingredient is limited. Accordingly, we evaluated the growth performance of juvenile Largemouth Bass (initial weight, 11.6±0.2 g [mean±SE]) reared for 8 weeks on practical diets (∼14.5% lipid, ∼42% digestible protein) containing different levels of menhaden fish meal (MFM), Asian carp meal (CFM), or a 50:50 blend of these ingredients such that 40% (40 MFM, 40 CFM) or 60% (60 MFM, 60 CFM, 60 Blend) of the estimated digestible protein content was derived from fish meal. Weight gain (329–388%), feed conversion ratio (0.78–0.97), and specific growth rate (2.65–2.88% body weight/d) were generally consistent among treatments. Although our results suggest that performance is greater among fish fed diets with greater fish meal inclusion, regardless of its origin, this trend was not supported by clear statistical evidence. Asian carp fish meal appears to be broadly equivalent to MFM in feeds for Largemouth Bass. Development of CFM as a feed ingredient may offer producers of Largemouth Bass and other carnivorous fishes some savings in feed cost and encourage the harvest of invasive Asian carp.