Effect of fresh and dry forage of two grasses and two legumes species on fatty acid profile and nutritional index of milk and cheese

The aim of this study was to evaluate the fatty acid profile and Health Promoting Index (HPI) of milk and cheese obtained from goats fed with fresh and dry forage of grasses and legumes. Forty Derivata di Siria goats homogeneous for milk production, days of lactation and BCS were allotted to four groups and they were fed with two grasses: Lolium perenne fresh (LF) and dry (LD), Hordeum vulgare fresh (HF) and dry (HD), and two legumes: Medicago sativa fresh (MF) and dry (MD) and Vicia sativa fresh (VF) and dry (VD). The milk was processed as Caciotta cheese and ripened for 20 days. Each trial lasted 15d, 10d for adaptation and 5d for experimental period. The lipid fraction of milk was extracted and fatty acids (FAs) were converted in methyl esters then separated and quantified by gas chromatography. The FAs peaks were identified using single and mixture of standard FAs. The nutritional index HPI was calculated according to Chen et al., (2004). The statistical analysis of data was carried out by GLM procedure of ANOVA. Mean values, expressed in g/100 g FA, were compared by Tukeytest. In cheese and milk from legumes groups were observed minor significant difference of FA profile compared to grasses groups. In cheese from legumes MF and VF groups, ALA (0.979 vs. 0.763; 1.549 vs. 1.418), omega-3 (1.824 vs. 1.079; 1.97 vs. 1.78) and Long Chain Fatty Acids (LCFA) (42.97 vs. 35.37; 37.53 vs. 37.21) were significantly lower (P < 0.05) than MD and VD, respectively. The higher HPI was observed in cheese (0.531) of MF than in cheese of VF group. Legumes species did not affected milk FA profile and nutritional index. The HF group was characterized by differences (P < 0.05) between milk and cheese for SFA, INFA, MUFA, PUFA, omega-3 and LCFA. Cheese from HF and HD exhibited a decrease (P < 0.05) for ALA (0.725 vs. 0.598), SFA (64.85 vs. 60.62), omega-3 (1.35 vs. 0.96) and an increase (P<0.05) for MUFA (28.94 vs.33.37) omega-6 (3.3 vs. 3.7), LCFA (47.33 vs. 50.35) and HPI (0.66 vs. 0.78). On the contrary, in cheese from LF to LD an increase (P < 0.05) of ALA (0.511 vs. 0.652), MCFA (38.23 vs. 41.17) and LCFA (35.35 vs. 40.44) was detected. The grasses species especially Hordeum vulgare seems to provide a footprint clearer than legumes species and Lolium perenne. Also the differences between products were emphasized in the fresh form of the herbage.