Effect of dietary inclusion of rumen-protected flaxseed oil (Linum usitatissimum) on intake, ingestive behavior, diet particle selectivity, digestibility, nitrogen balance, and blood parameters of lambs

Abstract This study evaluated the effects of rumen-protected flaxseed oil (RPFO; 30% flaxseed free oil and 70% carnauba wax) on intake, digestibility, ingestive behavior, nitrogen balance, and blood parameters in crossbred male lambs (Santa Inês × mixed breed). Fifty lambs (20.5 ± 3.0 kg; five months old) were assigned to a completely randomized design with five treatments: control, 4% and 8% free oil, and 4% and 8% RPFO ( n  = 10 per treatment). Flaxseed free oil inclusion, regardless of form, significantly affected intake, digestibility, feeding behavior, and nitrogen metabolism ( P  P  = 0.009) dry matter intake (DMI), whereas 4% RPFO resulted in the highest DMI. Crude protein and neutral detergent fiber corrected for ash and protein ( a NDFom) intakes decreased ( P  P  P  P  P  P  > 0.05). The RPFO mitigated negative effects of unsaturated lipids on rumen function, whereas high free oil reduced intake and performance. However, RPFO levels tested did not improve overall efficiency, indicating the need for further optimization.