Effects of dietary protein levels on growth and body composition of juvenile (age-1) Black Buffalo Ictiobus niger

Populations of Black Buffalo Ictiobus niger, a broadly-distributed catostomid species native to the Mississippi River basin, are in decline, similar to many other catostomids. Artificial propagation and culture are frequently a part of native species recovery plans, and developing formulated diets is a critical component of these plans. However, studies establishing protein requirements for catostomids are limited, particularly for larger juvenile to sub-adult sizes, even though catostomids are commonly reared to these sizes. Therefore, we conducted a 10-week growth study to evaluate optimal protein levels in juvenile (age-1) Black Buffalo (mean +/- SE: total length = 218.7 +/- 0.8 mm, weight = 148.5 +/- 1.6 g). Five practical diets were formulated to contain 30, 34, 38, 41, and 45% crude protein with each diet fed to four replicate tanks (400-L) containing 10 fish each. Fish fed a diet containing 41% crude protein had greater biomass gain (total weight gain for all fish in the tank) when compared to other diets. Individual weight gain (percent increase) was greater in fish fed diets containing 41% and 45% protein compared to lower protein diets. Results from this study suggest a diet with 41% crude protein would produce optimal growth for juvenile (age-1) Black Buffalo.