Use of high protein distiller's dried grain with yeast in practical diets for the channel catfish, Ictalurus punctatus

Abstract

As the ethanol industry matures and adopts new technologies, the co-products produced are also changing with their composition adjusted to meet feed industry needs. High protein distillers dried grain with yeast (HP40Y) is a relatively new product which is a variant of distillers dried grains that could be used as an improved protein source in catfish feed formulations. To evaluate the efficacy of HP40Y, a 10-weeks growth trial was conducted on the growth performance of juvenile catfish, Ictalurus punctatus (mean initial weight 1.80 ± 0.05 g). In the growth trial, graded levels of HP40Y (0.00, 3.10, 6.20 and 9.30%) were used to replace poultry meal (PM: 6.0, 4.0, 2.0 and 0.0%) and other series of diets were used with HP40Y (5.0, 10.0, 15.0, 20.0, 30.0 and 40.0%) to replace soybean meal (SBM: 51.00, 46.49, 41.90, 37.40, 28.20, 19.20%). Analysis of Covariance (ANCOVA) indicated a significant interaction between replaced protein (PM and SBM) and the inclusion level of HP40Y (up to 20%) on biomass, mean final weight, weight gain, and FCR (P < 0.05) of catfish. Therefore, the two sets of diets were analyzed separately. One-way Analysis of Variance (ANOVA) followed by Tukey multiple comparison test was used to detect significant differences between treatment means while regression analysis was used to determine the relationship between HP40Y inclusion level in the diet and weight gain and whole-body protein level of fish. In PM replacement series, complete replacement of PM with HP40Y in diet PDG9 resulted in poor performance, indicating a possible nutritional deficiency when the animal protein was removed. As a replacement for SBM, increasing levels of HP40Y only resulted in reduced growth of catfish when included in the diet at 30 and 40%. Results indicate that HP4Y is a good protein source when used at levels less than 30% of the diet.