USE OF HIGH PROTEIN DISTILLER'S DRIED GRAIN AS AN ALTERNATIVE INGREDIENT IN PRACTICAL DIETS OF DIFFERENT SPECIES (Ictalurus punctatus, Litopenaeus vannamei and Oreochromis niloticus)
Type of DegreePhD Dissertation
School of Fisheries, Aquaculture, and Aquatic Sciences
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Increasing worldwide competition and shifts in demand, technological advancements, and innovative research findings are triggering the ingredient manufacturing industry to include modified processing technologies and novel ingredients. New technologies have been introduced by the ethanol industry to improve the efficiency of ethanol production, resulting in new types of distiller dried grain with different nutrient profiles. One of the new processing techniques removes fibrous corn components before fermentation and removes the soluble fraction after fermentation to produce a high protein distiller grain with yeast (HP50Y) with 50% protein and a second product (HP40Y) that is 40% protein. The technique used to make these two ingredients was the same, however, performance of both products was needed to determine efficacy. High protein distillers dried grain with yeast is a relatively new product which is a variant of distillers dried grains that could be used as an improved protein source in animals feed formulations. To evaluate the efficacy of HP40Y and HP50Y, numerous laboratory-based trials were conducted at the E.W. Shell Fisheries Center at Auburn University in Auburn, Alabama. A 10-week trial was conducted to evaluate the growth performance of juvenile catfish, Ictalurus punctatus (mean initial weight 1.80 ± 0.05g). 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 another 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%). Results 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 food conversion ratio (FCR) of catfish. In the poultry meal replacement series, complete replacement of PM with HP40Y 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 indicated that HP4Y is a good protein source when used at levels less than 30% of the diet. Another growth trial was conducted to evaluate the efficacy of HP50Y and HP40Y as a replacement for corn protein concentrate (CPC) in diets of Pacific white shrimp, Litopenaeus vannamei. In this trial, graded levels of HP50Y (0.0, 5.0, 10.0, 15.0 and 20.0%) were used to replace CPC (13.1, 10.0, 6.6, 3.5 and 0.2%). In the second series of diets, graded levels of HP40Y (5.0, 10.0, 15.0 and 20.0%) were used to replace CPC (10.5, 8.0, 5.5 and 2.5%) which was evaluated over a 40-day growth trial (mean initial weight 0.54 ± 0.01 g; n=4). At the conclusion, no significant differences were detected in growth, FCR, survival and food consumption of shrimp (p>0.05). However, results from regression analysis revealed a significant increase in weight gain (%)of shrimp as the percentage inclusion level of HP50Y and HP40Y increased in shrimp diets. Results indicated that HP50Y and HP40Y are both good protein sources and can be used up to 20% inclusion level in the diets of shrimp. A 10-week growth trial with tilapia was conducted, using nine diets formulated to contain 32% protein and 6% lipid. Each protein was included at various levels (0, 5, 10, 15 and 20%) replacing CPC on a protein basis. Juvenile tilapia (mean initial weight 5.23 ±0.20g) were evenly distributed in thirty-six, 75-L aquaria working as a recirculating system and fed twice daily to apparent satiation throughout the study. Tilapia exhibited no significant (p>0.05) differences in growth, FCR, survival, whole-body proximate composition, mineral composition, and hematological parameters when fed HP50Y and HP40Y supplemented diets compared to the control diet. Digestibility coefficients for the test ingredients were determined in tilapia for dry matter, energy, crude protein, individual and total amino acids using 1% titanium oxide as the inert marker with 70:30 replacement strategies. All the values were found to be within an acceptable range for the distiller grains when compared to the literature. Results from this study revealed that HP50Y and HP40Y both are good alternative protein sources and can be used up to 20% inclusion level in the diets of tilapia.