Effect of different diets on the fatty acid composition of buffalo bulk milk

What animals feed can affect buffalo milk fatty acids (FA) composition. Therefore, the diet could increase the content of polyunsaturated fatty acids (PUFA), omega 3 (n-3), and conjugated linoleic acid (CLA), improving the nutritional value of buffalo milk. The objective of this work was to evaluate the effect of diet and season on the composition of buffalo milk fatty acids. Over a year, 120 samples of bulk buffalo milk were taken from ten farms. Animals were fed with 10 different isoenergetic and isoproteic diets. The basic diet of each group was supplemented with different components representing about 3% in dry matter of total ration. The basic diet (B) comprised maize silages, alfalfa hay, corn grain, and soybean as concentrates. The second diet was  supplemented with linseed (L), brewer’s spent grain (T), alfalfa and mixed hay (H), corn grain (M), and grass (G) as additional constituents. Other farms included both grass and cottonseed (CG), grass and linseed (GL), or grass and brewer’s spent grain (TG) and grass, linseed and brewer’s spent grain (LTG). Fatty acids in buffalo milk were quantified after extraction and methylation by GC/FID. Data was analyzed through a bifactorial model with interaction (season x diet), using GLM procedure and the statement “contrast” by SAS Software to highlight the effect of the diet constituents. Seasonal effects were evident in milk FA. Spring and summer significantly increase the saturated fatty acids (SFA) and decrease the PUFA by about 10%. Diets containing linseed (L, LG, LTG) showed an increase (p<0.001) in PUFA n-3 (0.63 vs. 0.38 g/100g of fat) compared to the others. While milk from the CG and TG diets showed an increase (p<0.001) in PUFA n-6, the differences were also evident in the n6/ n3 ratio (3.1 vs. 5.2, p<0.001). Diets with T and M showed an increase (p<0.002) in SFA and a decrease (p<0.001)  in CLA (-20%). Instead, the G diet allowed a higher (p<0.0004) content of CLA (0.90 vs 0.74 g/100g of fat), highlighting the positive contribution of grass on ruminal activity. Contrarily, the addition of linseed and cotton- seed to the G diet caused a decrease (p<0.001) in CLA and branch fatty acids due to the excessive presence of PUFA. The feeds supplied attended all metabolic pathways, and in particular, linseed and grass could enrich the milk with functional compounds. However, the right balance must be found between the constituents to maximize their positive contribution.