Effects of Low Supplement Levels of Plant Oil and Type of Antioxidant on Meat Quality Parameters of Feedlot Lambs

Plant oil supplements have been used in ruminant feedlot diets as alternative high-density energy source.However, feeding ruminants with high levels of oil may adversely affect the rumen microbiome and function, negatively impacting performance and production. Plant oils high in polyunsaturated fatty acids (PUFA) may also affect animal products quality when PUFA escape or partially escape biohydrogenation. This study investigated the effects of a low inclusion level (1.62%) of a plant oil (commercial sunflower-soybean blend) on the physicochemical attributes, fatty acid profile, and shelf-display stability of longissimus thoracis et lumborum muscle of lambs fed high-energy starch-based diets. In addition, either a natural or synthetic antioxidant were included in the plant oil containing diets to evaluate their effects on maintenance of shelf-display stability with or without natural or synthetic antioxidants. Forty [n=40; average weight (± standard error of mean) 28 (± 0.836 kg)] were blocked by weight and randomly allocated to 4 dietary treatment groups [(1) control (Grain); (2) grain plus plant oil only (Oil); (3) grain plus plant oil with synthetic antioxidant (OilCaps); and (4) grain plus plant oil with natural antioxidant (OilNat)]. Feeding lambs with grain-based diets supplemented with plant oil, with or without natural or synthetic antioxidants, had no effects on meat physicochemical attributes (P>0.050) or color stability over 7 d of shelf display (P>0.050). Regardless of antioxidant inclusion, oil supplementation increased conjugated linoleic acid (CLA) composition in lamb longissimus muscle (P=0.028). Overall, results from this study suggest that grain-based feedlot diets supplemented with low inclusion levels of plant oil did not significantly affect shelf stability of lamb meat during display while both oil supplement and antioxidants increased the CLA content of longissimus muscle.