PS9-14. Effect of Dietary Flaxseed Inclusion on Meat Quality Traits of Texel-crossbred Lambs Finished in Feedlot.

Abstract The inclusion of oilseeds in feedlot lamb diets may represent an alternative to partially replacing cereal grains by providing lipids as an energy source instead of starch. Supplementing sheep with oilseeds may improve growth performance and carcass traits without compromising animal health. This study determined the effect of including flaxseed at 6% on a dry matter (DM) basis in feedlot diets on meat quality parameters in Texel crossbred lambs. Twenty-four lambs (12 females and 12 castrated males; 18.6 ± 1.06 kg; 43.2 ± 4.6 d) underwent a 24-d adaptation period from a pasture-based diet at the dam’s side to a feed lot diet (alfalfa hay and concentrate at a 40:60 forage-to-concentrate ratio), followed by an 84-d feedlot period until 40 kg BW. Animals were assigned to one of two dietary treatments: Control (CON), diet without flaxseed) and Flaxseed (LIN, diet containing 6% flaxseed DM). Feed was offered at 5% of BW, twice daily. Diets were formulated to be isoenergetic and isonitrogenous (17.8% crude protein and 2.7 Mcal ME/kg DM; NRC 2007). Male lambs (n = 13) were slaughtered. Steaks from the 12th and 13th thoracic vertebrae were evaluated: water-holding capacity (drip losses at 24 and 72 h, cooking losses, and expressible juice), pH, and color parameters (lightness - L*, redness - a*, yellowness - b*, flesh tone and saturation; CR-400 colorimeter after 30 min of blooming). Morphometric measurements included: ribeye area (REA); major and minor diameters (digital image analysis using ImageJ software) and backfat thickness. Flaxseed inclusion did not affect drip losses at 24 h (3.62 and 5.50% for LIN and CON respectively; P = 0.253) or 72 h (4.93 and 6.66%; P = 0.343), cooking losses (29.25 and 30.50%; P = 0.447) and expressible juice (29.01 and 30.9% for LIN and CON, respectively; P = 0.449). No significant differences were observed in pH (5.68 and 5.69; P = 0.839) and backfat thickness (0.63 and 0.75 cm for LIN and CON, respectively; P = 0.186). Flaxseed supplementation increased REA (16.63 vs. 14.12 cm² for LIN and CON, respectively; P = 0.045) and tended to increase the REA minor diameter (P = 0.062). Redness (P = 0.069) and saturation (P = 0.069) tended to be lower in LIN group, and no differences were observed for lightness (P = 0.159), yellowness (P = 0.283) and flesh tone (P = 0.254). The increase in REA in LIN group is consistent with Dorantes-Iturbide et al. (2022) and Bhatt et al. (2020), who reported that oilseed supplementation can enhance REA and carcass attributes in lambs. Overall, including flaxseed at 6% DM is a promising strategy to improve muscular development and meat production from feedlot lambs and attend to the increasing world animal’s protein demand.