Growth performance and digestibility comparison of 3 soybean oils and an animal-based highly saturated fat fed to broilers

Authors: ELMORE, KAYLA - Iowa State University; Kerr, Brian; BOBECK, ELIZABETH - Iowa State University

Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2023
Publication Date: 10/21/2023
Citation: Elmore, K.M., Kerr, B.J., Bobeck, E.A. 2023. Growth performance and digestibility comparison of 3 soybean oils and an animal-based highly saturated fat fed to broilers. Journal of Applied Poultry Research. 32(4). Article 100376. https://doi.org/10.1016/j.japr.2023.100376.
DOI: https://doi.org/10.1016/j.japr.2023.100376

Interpretive Summary: Various refined, crude, and recycles lipids, depending upon their costs, can be used in poultry feeding programs because they provide a concentrated source of energy compared to other commonly used feedstuffs. The digestibility and caloric value of refined, deodorized, bleached soybean oil is typically high, but different soybean oil extraction methods may produce oils with slight differences in digestibility and consequently their caloric value to animals. The current study was conducted to evaluate the digestibility energy content of differentially extracted soybean oils and to compare to other types of soybean oil, and to saturated fat product with a known low digestibility in swine. The data show that regardless of extraction method, all soybean oils were highly digestible while the saturated fat product was poorly digested. This information is important for nutritionists at universities, feed companies, and poultry production facilities for the determination of the energy value of commonly used lipids in feed formulations and provides a basis from which to assess their economic value.

Technical Abstract: Soybean processing methods result in soybean oils with different compositions, which can alter their digestibility and ultimately broiler growth performance. To compare different soybean oil sources, a 42-d study was performed using 780 straight-run Ross 308 broilers randomly assigned to 1 of 5 dietary treatments. Dietary treatments consisted of: 1) a corn-soybean meal negative control (NC) diet containing 4.5% fine sand, or the NC diet with an additional 400 kcal of AME/kg from 4.5% fat inclusion of: 2) refined, bleached, and deodorized soy oil (RBD-SO, positive control); 3) animal-based lipid product containing a high percentage of saturated C16:0 and C18:0 fatty acids (SAF); 4) ExPress® soy oil (ExP-SO); or 5) mechanically-processed soy oil (Mech-SO). RBD-SO, ExP-SO, and Mech-SO supplementation significantly impacted feed intake (FI), gain, and FCR when compared to broilers fed the SAF or NC diets, with ExP-SO having the most efficient overall FCR (P<0.05). Lower FI and increased weight gain were consistently observed in RBD-SO, ExP-SO, and Mech-SO diets over all growing phases. Similarly, SO supplementation positively impacted dietary energy, with an increased average apparent total tract digestibility (ATTD) of 12.2% and AME of 11.4% in SO diets compared to SAF. A similar trend was observed in lipid energy determination, with the 3 SO products having 63.1% greater ATTD and AME compared to SAF. Although few differences were observed among SO diets with varying production methods, these results support the use of RBD-SO, ExP-SO, and Mech-SO products to promote performance and digestibility in comparison to SAF products.