Changes in the rumen and milk fatty acid profile and milk composition in response to fish and microalgae oils supplementation to diet alone or combination in dairy goats

Dietary fat supplementation in the ruminant diet is known to be a good strategy to increase beneficial milk fat compounds such as polyunsaturated fatty acids (PUFA) and conjugated linoleic acid (CLA). To the best of our knowledge, this is the first study to compare and combine fish oil (FO) and Schizachyrium microalgae oil (MA) supplementation to the diets of dairy goats. This study aimed to investigate the inclusion of FO, MA, and their combinations in the diets for effects on performance, milk composition, milk fatty acids, ruminal biohydrogenation, and fermentation parameters in dairy goats. Four cannulated Saanen dairy goats in the second lactation with a daily 3.25 +/- 0.10 L milk yield and 45.08 +/- 0.5kg body weight were assigned to four treatments: (1) no lipid supplementation (CON), (2) supplementation with 20 g/kg of FO, (3) 20 g/kg of MA, (4) 10 g/kg FO + 10 g/kg MA (FOMA). Milk and fatty acid composition were determined in samples taken from three consecutive days of milking after 21 days of adaptation. On the same days, ruminal fatty acids were determined. Dietary oil supplementations did not affect the performance parameters in dairy goats. However, fat yield decreased in FOMA. The oil supplementations did not affect the milk composition. However, cholesterol in milk increased in FO (P < 0.05). C16:0 FA in milk increased in MA. C18:0 FA in milk was lowest in MA. The highest milk trans-11 C18:1 FA was in the MA group. Cis-9, trans-11 CLA, trans-10, cis-12 CLA, and & sum;PUFA increased in milk with oil supplementations to diet. Milk & sum;SFA was the lowest in the FO group. Ruminal C18:0 fatty acid was decreased in oil supplementations to diet. Ruminal trans-11 C18:1, cis-9, trans-11 CLA, trans-10, and cis-12 CLA were increased in oil-supplemented groups. Ruminal fermentation parameters were not affected by oil supplementation to diet; however, there was a propionate increase in the MA group. The serum glucose and cholesterol levels were not affected by oil supplementation to diet.