Abstract

We aimed at evaluating the best unsaturated fatty acid candidate (vegetable oil) for blending (dry matter-DM basis) with cashew nutshell liquid (CNSL) to improve feed intake, digestibility, nitrogen balance, growth, and carcass traits in sheep. Forty uncastrated male Santa Ines × Dorper crossbred sheep (n = 8/treatment) weighting 24.44 ± 1.5 kg were used. Animals were randomly assigned to a completely randomized design and received one of the following treatments: a control group consisting of a blend of phenolic lipids (CNSL at 0.5%) and canola oil (a monounsaturated fatty acid source, MUFA, at 1.5%), and four treatment groups with CNSL (0.5%) combined with 1.5% of a high polyunsaturated fatty acid (PUFA) vegetable oil (corn, soybean, sunflower, or cottonseed oil), as DM basis. Feeding sheep with CNSL + canola oil resulted in higher SFA, UFA, and MUFA and lower PUFA’s (P < 0.05) intakes. The TDN intake was lower for the CNSL + corn oil diet than the other oils (P < 0.0001). The DM and NDF digestibility were higher for CNSL + cottonseed oil (PUFA) or canola oil (MUFA) diets than other oils (P < 0.05). The CNSL + soybean oil blend promoted a lower urinary N excretion (P = 0.047) in sheep. Growth and carcass traits were not affected by the oil’s composition in the blends. The level of saturation was confirmed as such a determining factor in the DM and NDF digestibility since the oil containing the highest concentration of MUFA (canola oil) showed better digestibility compared to other PUFA-rich oils; however, without effect on the performance and feed efficiency of the sheep.