Effects of palm oil supplementation and fibrolytic enzymes in high forage diets on growth, carcass characteristics and fatty acid profiles of lambs

Abstract

This study investigated the effects of palm oil and fibrolytic enzyme supplementation in high forage diets on growth, carcass characteristics and fatty acid composition of lambs. Forty South African Mutton Merino ram lambs were randomly assigned to four treatment groups (n = 10 lambs/ treatment) and fed a basal total mixed ration (TMR). The treatments were: TMR diet with Megalac as bypass oil (control); TMR diet supplemented with 3% palm oil; TMR diet with cellulase and xylanase enzymes and TMR diet supplemented with 3% palm oil and cellulase and xylanase enzymes. The lambs were slaughtered at a target weight of about 42 kg. Palm oil supplementation resulted in a longer feeding period (P < 0.05) and lower dressing percentage (P < 0.01), but the carcasses had higher meat yield (P < 0.01) and lower fat content (P < 0.05) compared to the other treatment groups. Additionally, palm oil supplementation increased the proportion of C18:0 (P < 0.05) while decreasing (P < 0.05) the proportion of C14:0 (P < 0.05) and C16:0 (P < 0.05) in fat depots, which may be beneficial for human health. The fibrolytic enzyme treatment had minimal effects on growth, carcass characteristics, meat quality and fatty acid composition of lambs. The interaction effect of palm oil and fibrolytic enzymes had positive effects on the UFA: SFA ratio due to an increase (P < 0.05) in C20:3n6 and C20:4n6 and a reduction (P < 0.05) in saturated fatty acids. The results suggest that methane mitigation strategies through palm oil and enzyme supplementation can be used in lamb diets without adverse effects on product quality.