The effect of fish and soybean oil inclusion in goat diet on their milk and plasma fatty acid profile

Abstract

A good nutritional strategy for enhancing the bioactive fatty acids (FAs) in goat milk could be the dietary supplementation with a moderate level of a combination of soybean oil with fish oil (SFO). Thus, the objective of this study was to determine the effects of a moderate forage diet supplementation with SFO on milk chemical composition and FA profile, as well as on plasma FA. Twelve dairy goats were assigned to two homogenous sub-groups. Treatments involved a control diet without added oil, and a diet supplemented with 55.5g soybean oil and 11.1g fish oil/day/animal. The results showed that SFO diet modifies the milk and plasma FA profile in the absence of any effect on milk fat content and on milk yield. In blood plasma the concentrations of trans-11 C18:2 (VA), cis-9, trans-11 C18:2 CLA, trans-10, cis-12, C18:2 CLA, C20:5n−3 (EPA) and C22:6n−3 (DHA) were significantly higher while those of C14:0, C15:0 C16:0 and C18:0 were lower in goats fed with SFO diet compared to control. The SFO supplementation in goat diet increased the concentrations of VA, cis-9, trans-11 C18:2 CLA, trans-10, cis-12, C18:2 CLA, EPA, DHA, monounsaturated FA (MUFA), polyusaturated fatty acids (PUFA) and n−3 FA and decreased those of short chain FA (SCFA), medium chain FA (MCFA), the saturated/unsaturated ratio and the atherogenicity index value in milk compared with the control. In conclussion, the SFO supplementation at the above levels in a goat diet, with moderate forage to concentrate ratio, improved the milk FA profile from human health standpoint.