J Anim Sci. 2026 Aug 6:skag237. doi: 10.1093/jas/skag237. Online ahead of print.
ABSTRACT
Odd-chain fatty acid metabolism has recently become a topic of interest in human health research. This interest has followed observations of inverse associations between pentadecanoic acid (C15:0) and/or heptadecanoic acid (C17:0) with cardiovascular disease, type 2 diabetes mellitus, and hypertension risk. Both C15:0 and C17:0 are found in ruminant-derived fats, such as dairy products, tallow, and beef. Given the potential health benefits of odd-chain fatty acids, our objective was to determine if the proportion of odd-chain fatty acids in beef could be increased by including tallow in the finishing diet of beef steers. Fatty acid and lipidomics analyses were performed on strip steaks and marbling dissected from beef strip loins, respectively, from carcasses fed one of two corn-based finishing diets (n = 5/treatment), which included either no added fat or added tallow at 3.5% diet dry matter. In the tallow-containing diet, tallow replaced high-moisture corn and all other feed ingredients were held constant. Data were analyzed using R and RStudio using Welch's two-sample t-tests. For all analyses, loin/animal was considered the experimental unit. Effect of diet was considered significant at P ≤ 0.05 and tendencies at P ≤ 0.10. The tallow fed in this experiment contained 0.5, 1.2, and 0.6 g/100g fatty acid methyl esters (FAME) of C15:0, C17:0, and C17:1 (heptadecenoic acid), respectively, whereas high-moisture corn contained < 0.1 g/100g FAME of C15:0, C17:0, and C17:1. Beef from tallow-fed steers had increased C17:1 (P = 0.03) and tended to have increased C15:0 (P = 0.06) and C:17:0 (P = 0.07), but C14:0, C14:1, C16:0, C16:1, C18:0, C18:1, and C18:2, and C18:3 did not differ (P ≥ 0.21). Marbling from tallow-fed steers appeared to have a remodeled triglyceride (TAG) composition, with significantly increased C48:2 and C50:3 and reduced C52:1 (P ≤ 0.03) and tended to have increased C46:1, C50:2, and C54:4 (P ≤ 0.10). Marbling from tallow-fed steers also had an increased percentage of C17:0 among phosphatidylcholine acyl chains (P < 0.01). Although odd-chain fatty acids represent a minor proportion of the nutrients in beef, beef can provide levels of odd-chain fatty acids at levels comparable to over-the-counter supplements. Tallow supplementation is a practical means for increasing odd-chain fatty acids in beef and additional research is warranted to determine if higher dietary inclusion levels offer additional benefits.
PMID:42560032 | DOI:10.1093/jas/skag237