Effect of feeding on fatty acid composition of muscles and adipose tissues in young goats raised in the Argan tree forest of Morocco

The characteristics of meat from goats raised in the Argan tree forest in the south-western part of Morocco were studied in two experiments. Each experiment was carried out on three groups of six male goats. They were reared either indoors (IC) and fed concentrate or outdoors where they grazed in the Argan tree forest and were offered concentrate (OC) or only Argan fruit pulp (OS). Outdoor-raised goats had a very low growth rate in the first experiment (34 g/d), whereas it was relatively high in the second experiment (64 g/d) in which herbaceous vegetation availability was higher. In each experiment, omental (OM) and perirenal (PR) weights were the lowest in the two groups of goats raised outdoors. Lipid and cholesterol contents in muscles were lower in goats raised in the Argan tree forest than in those raised indoors. Outdoor-raised goats had particularly high proportions of odd-chain fatty acids (FA), branched-chain (FA) of the iso and anteiso series in adipose tissues and muscles and higher n − 6 and n − 3 polyunsaturated FA (PUFA) proportions and a lower n − 6:n − 3 PUFA ratio than indoor-raised goats. Indoor-raised goats had a higher proportion of palmitic acid and a lower proportion of archidic acid than outdoor-raised goats. In indoor-raised goats, the proportions of Δ9 straight-chain mono-unsaturated fatty acids (MUFA) (C16:1n − 7 and cis C18:1n − 9) were relatively higher than those of total MUFA, because of lower percentages of some MUFA, such as C16:1n − 9 and other isomers of oleic acid. The low fat content and FA profile of the meat from the goats reared in the Argan tree forest conveyed beneficial characteristics to this meat in regards to human health. The relatively high contents of branched-chain FA of iso and anteiso series and PUFA in the meat from goats raised in the Argan tree forest could be considered as a sign of typicity.