Effect of dietary Marula (Sclerocarya birrea caffra) nut meal on the growth performance, carcass traits and meat quality of Dorper lambs

Abstract

Use of Marula nut meal (MNM) to replace Soyabean meal (SBM) as a dietary protein source in lamb fattening diets by determining effects on growth performance, carcass yield and meat quality was evaluated. MNM replaced SBM on a crude protein (CP) basis, in five diets, at 0%, 25%, 50%, 75% and 100%, respectively. Forty 112-day old entire male Dorper lambs (average body weight: 22.1 ± 3.3 kg) were randomly allocated to the diets and fed ad libitum for 63 days. Weekly and final body weight (FBW), body weight gain (BWG), average daily gain (ADG), daily feed intake (FI) and feed conversion ratio (FCR), warm and cold carcass weight, dressing percentage, meat (physical and chemical attributes) quality were determined. Dietary MNM caused no significant difference in FBW, BWG, ADG, FI, FCR, carcass weight and the meat’s physical attributes compared to SBM. At 25% and 100% dietary substitution of SBM (CP basis), MNM significantly (P < 0.05) reduced meat protein content. Feeding MNM-based diets produced meat with higher fat content compared to the control SBM diet (P < 0.05). The meat’s total monounsaturated fatty acid content, dominated by oleic acid, increased with increasing dietary MNM. At 100% substitution of SBM, dietary MNM produced meat with the highest (P < 0.05) oleic acid content. The results obtained in the study showed that MNM can replace SBM in lamb fattening diets without compromising growth performance, feed utilisation efficiency, carcass yield and physical attributes of meat. MNM can potentially be utilised to improve lamb quality by increasing its oleic acid content.