Extruded Linseed Supplementation in Dairy Goat Diet: Effects on Productive Performance and Fatty Acid Profile of Bulk Milk, Fresh and Ripened Cheese

Aim of the study was to evaluate the effects of diet supplementation with Extruded Linseed (EL) on goat milk yield and gross composition and Fatty Acid (FA) composition of milk, fresh and ripened cheese. During a 10 weeks period, 26 mid-lactating Saanen goats were divided into two balanced groups and fed a total mixed ration supplemented (EL group) or not (C group, control) with 3 g/100 g diet of rumen unprotected EL. Bulk milk samples, fresh and ripened cheese were analysed for fat, protein, lactose and FA profile. Results showed that milk fat was 3.1 g kg-1 higher in the EL group. Milk, fresh and ripened cheeses showed similar responses in FA composition. Dietary inclusion of EL enhanced the concentrations of caprylic, capric and stearic acids, total trans-octadecenoic acids, the majority of non-conjugated octadecadienoic acids and α-linolenic acid. Significant reductions were observed for palmitic acid, iso branched-chain FA, cis-9 monounsaturated FA, the sum of c9t11+t7c9+t8c10 conjugated linoleic acid isomers, linoleic acid and other long-chain n6 FA. The n6/n3 FA ratio and the estimated Δ9-desaturase activity were also significantly reduced. No significant influence of EL supplementation was instead observed for total polyunsaturated, aiso branched-chain and very long-chain n3 FA. The positive effects of the EL inclusion on the nutritional quality of milk and cheese lipids (lower hypercholesterolemic saturated FA and n6/n3 FA ratio and higher caprylic, capric and α-linolenic acids contents) were however accompanied by reduced concentrations of potentially beneficial FA such as 14-methylpentadecanoic (C16 iso), oleic and conjugated linoleic acids.