UC Davis

Healthfulness and palatability are key quality attributes of both conventional meat and meat alternatives, and the fatty acid profile is a major determinant of these characteristics. Therefore, understanding lipid metabolism in primary bovine adipocyte cultures is essential for improving beef quality and advancing the development of cell-cultured fat for cultivated meat production. Beef contains a diverse array of fatty acids, including numerous intermediates generated during the biohydrogenation of dietary unsaturated fatty acids by ruminal microbes. The proportions of ruminal biohydrogenation intermediates (BHIs) are influenced by the animal's diet. In feedlot cattle, high-grain diets induce the trans-10 shift, resulting in increased production and tissue accumulation of trans-10, cis-12 conjugated linoleic acid (t10,c12 CLA) and trans-10 18:1 (t10-18:1), at the expense of trans-11 BHIs. These fatty acids have been implicated in regulating lipogenesis, Δ9-desaturase activity, and fatty acid composition, thereby influencing beef quality and nutritional value. The first study investigated the effects of linoleic acid (LNA) and its t10 BHIs (t10-18:1 and t10,c12 CLA) on lipid metabolism in primary bovine intramuscular adipocytes, with particular focus on t10-18:1, whose role in regulating lipid metabolism remains poorly understood. We demonstrated that LNA and its t10 BHIs differentially regulate lipid metabolism in primary bovine intramuscular adipocytes, highlighting the importance of the number, position, and configuration of double bonds in determining fatty acid bioactivity. Specifically, t10-18:1 increased SCD1 expression and Δ9-desaturation indices in a dose-dependent manner, whereas t10,c12 CLA and LNA reduced the expression of key lipogenic genes, including FAS, ACC, and SCD1, and decreased Δ9-desaturation indices without significantly affecting cellular lipid accumulation. The second study aimed to compare the fatty acid composition of cell-cultured bovine fat with that of conventional beef fat using a 2D primary bovine adipocyte culture model. Primary adipocytes isolated from kidney, intramuscular, and subcutaneous adipose tissues were compared with their corresponding source tissues to determine the extent to which cultured adipocytes retain depot-specific fatty acid characteristics. The study also evaluated whether oleic acid supplementation could improve the fatty acid composition and nutritional quality of cultured fat. Cultured adipocytes exhibited reduced fatty acid diversity, higher saturated fatty acid content, lower cis-monounsaturated fatty acid proportions, and less favorable lipid quality indices than their corresponding source tissues. Although oleic acid supplementation partially improved the fatty acid profile, it did not fully reproduce the fatty acid composition of conventional beef fat. Collectively, these studies advance our understanding of the role of t10 BHI in regulating lipid metabolism in bovine adipocytes and of the nutritional composition of cell-cultured bovine fat, providing a foundation for improving beef fat quality and optimizing cell-cultured fat for cultivated meat production.