Tissue composition, physicochemical characteristics, and lipid profile of meat from lambs fed total mixed ration silage containing pornunça (Manihot sp.)

This study aimed to evaluate leg tissue composition, physicochemical characteristics, and the lipid profile of meat from feedlot-finished lambs fed total mixed ration silage (TMRS) or total mixed ration (TMR) containing pornunça ( Manihot sp.), at different forage-to-concentrate (F:C) ratios. Thirty-two crossbred, non-castrated lambs with an average initial BW of 19.6 ± 2.10 kg were used in a randomized complete block design, arranged in a 2 × 2 factorial scheme, two types of TMR (silage and fresh) and two F:C ratio (40:60 and 50:50): TMRS40:60, TMRS50:50, TMR40:60, and TMR50:50. The 60-day experiment included 10 days of adaptation and 50 days of data collection. Variables were analyzed using mixed models, and means were compared by Tukey’s test ( P ≤ 0.05). The TMR40:60 diet resulted in greater dry matter intake (DMI; P = 0.03) and higher average daily gain (ADG; P = 0.04) compared with TMRS40:60. TMR increased slaughter BW ( P = 0.04) and leg weight ( P = 0.02), regardless of the F:C ratio. TMRS40:60 resulted in a higher bone proportion ( P = 0.02) than TMR40:60. Moisture, crude protein, lipid, and ash contents in the Longissimus muscle (LL) were not affected ( P > 0.05) by the diets. The 50:50 F:C ratio increased L * values of the LL and cooking losses ( P = 0.03). TMRS increased 18:1- trans content ( P = 0.04), whereas TMR increased 18:1- c 9 levels ( P = 0.05). In conclusion, pornunça is a viable alternative roughage source in TMR, either ensiled or fresh, at 40:60 and 50:50 F:C ratios, without compromising meat quality.