A comparison of the proximate, fibre, mineral content, amino acid and the fatty acid profile of Marula (Sclerocarya birrea caffra) nut and soyabean (Glycine max) meals

BACKGROUND: As a result of shortages and the cost of the currently utilized conventional dietary protein sources in the Sub-Saharan Africa feed industry, the chemical evaluation of available non-conventional sources for feed is imperative. One such source is Marula nut meal (a by-product of Marula oil extraction). The present study chemically characterized the nutritional composition of two differently processed Marula nut meals (MNMs) and compared them with that of solvent extracted soyabean meal (SBM). RESULTS: The MNMs had higher dry matter, ether extract and gross energy but lower crude protein and ash contents compared to SBM. The cold press produced Marula nut meal (MNM2) had higher arginine than the hydraulic filter press produced Marula nut meal (MNM1) and SBM. The meals had similar neutral and acid detergent fibre contents. The MNMs had higher phosphorus, magnesium and copper concentrations than SBM. Although the total saturated fatty acid proportion was similar across the meals, total monounsaturated and polyunsaturated fatty acid proportions were higher in MNMs and SBM, respectively. Oleic acid was higher in MNMs than in SBM. CONCLUSION: The low crude protein content in MNMs compared to SBM is comparable with other conventional dietary protein sources. Thus, the MNMs could be used as protein and energy feed ingredients. © 2017 Society of Chemical Industry.