|HARDING, KARI - North Carolina State University|
|MALHEIROS, DIMITRI - North Carolina State University|
|WYSOCKY, REBECCA - North Carolina State University|
|MALHEIROS, RAMON - North Carolina State University|
|ANDERSON, KENNETH - North Carolina State University|
Submitted to: International Journal of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2022
Publication Date: N/A
Interpretive Summary: Scientists are searching for different feed ingredients that can be fed to poultry without decreasing growth and the production of meat or eggs. However, it is important to understand how birds digest these feed ingredients to reach their maximum potential. There are very few studies examining the nutrient digestibility of peanuts and/or sweetpotato by-products. Hence, in this study we aimed to determine the nutrient digestibility of high-oleic peanuts and sweetpotato by-products by determining the metabolizable energy, the dietary nitrogen retention, the protein digestibility, and the fat digestibility. We fed four experimental diets formulated to be nutritionally complete to hens for six weeks. Each diet had the inclusion of an indigestible marker to determine the nutrient digestibility of feeding an 8% inclusion of high-oleic peanuts (HOPN), a 4% inclusion of sweetpotato by-products (SWP), or a 4% inclusion of sweetpotato by-products + 4% inclusion of high-oleic peanuts (SWP + HOPN) as well as a control corn and soybean meal diet. The control diet as well as the HOPN had better apparent metabolizable energy compared to the SWP and the SWP + HOPN diets, suggesting that these birds had better access to high energy feed ingredients in the control and HOPN diets allowing them to digest and utilize the energy for production. The apparent nitrogen retention was the same for all dietary treatments, with the lowest dietary nitrogen (protein) retention in the SWP treatment group. Birds fed the SWP + HOPN diet had the highest fat digestibility percentages when compared to the other diets and the control had the lowest fat digestibility percentage. The SWP experimental diet had the highest protein digestibility when compared to the other treatment groups. To summarize, this study demonstrates that feeding high-oleic peanuts or sweetpotato by-products separately have similar or improved fat and/or protein digestibilities as compared to conventional feed ingredients and could possibly be used as alternative feed ingredients for laying hens. However, feeding a combination of sweetpotato by-products and high-oleic peanuts in hen diets may require the supplementation of additional dietary energy and protein. The impact of this study is the validation of sweetpotato by-products as a value-added alternative feed ingredient for egg-producing hens and sustainable utilization of a considerable agricultural waste by-product.
Technical Abstract: As the evaluation of alternative feed ingredients continues, it is important to understand the nutrient digestibility of those ingredients that are viable options. Very few studies have examined the nutrient digestibility of unblanched high-oleic peanuts and/or sweetpotato by-products when fed to laying hens. The goal of this study was to compare, the apparent metabolizable energy corrected for nitrogen, apparent nitrogen retention, apparent fat digestibility, and apparent protein digestibility. To meet these objectives, four isocaloric, isonitrogenous diets were fed to 64 Shaver hens for six weeks. Each diet had a 2% inclusion of Celite indigestible marker. The four diets were a 1) conventional corn-soybean control; 2) an 8% inclusion of high oleic peanut treatment (HOPN); 3) a 4% inclusion of sweetpotato by-product (SWP); and 4) a 4% sweetpotato by-product + 4% high-oleic peanut (SWP + HOPN) inclusion. The control and high-oleic peanut fed birds had greater apparent metabolizable energy values compared to the other treatment groups, suggesting that the energy from these diets was more accessible for the birds to digest while the SWP + HOPN diet had the least (P < 0.0001). The apparent nitrogen retention for the hens fed the SWP treatment was significantly lower (P < 0.001) than all other treatments. The SWP + HOPN diet had highest apparent fat digestibility percentages (P < 0.0001) than any of the other treatments. The conventional control diet had the lowest fat digestibility with the HOPN diet being slightly higher than the control. The SWP diet had significantly less digestible fat percentage than the SWP + HOPN but was significantly higher than all other treatments. The apparent protein digestibility of SWP diet was higher than all treatments (P < 0.0001). Control and HOPN treatments were lower than the SWP diet. In conclusion, these studies demonstrate that high oleic peanuts and sweetpotato by-products fed individually have comparable fat and protein nutrient digestibilities and could potentially serve as a value-added alternative feed ingredient for layers. However, when sweetpotato by-products and HOPN are fed in combination an additional dietary energy source may be needed to provide optimal metabolizable dietary energy. The impact of this study is the validation of sweetpotato by-products as a value-added alternative feed ingredient for egg-producing hens and sustainable utilization of a considerable agricultural waste by-product.