Effects of sucrose and sunflower oil addition to diet of Saanen dairy goats on performance and milk fatty acid profile

• Replacing barley grain with sucrose improved milk yield and the 4% fat-corrected milk yield in dairy goats.
• Sucrose lowered ruminal pH and acetate proportions whereas molar proportions of butyrate were not affected.
• Dietary inclusion of sunflower oil had increased the supply of total trans-fatty acids and PUFA to milk.
• Sucrose did not change milk fatty acids profile when sunflower oil was added to diet.

The current study was conducted to examine the effect of dietary sucrose with or without sunflower oil on dairy goat performance, ruminal fermentation and milk fatty acid (FA) profile. Sixteen Saanen goats were assigned to the experimental diets control (basal diet without added oil and sucrose (CON), the basal diet supplemented with sunflower oil (SO, 3.7% of diet DM), sucrose (SU, 5.2% of diet DM) and sunflower oil plus sucrose (SO+SU, 3.7% and 5.2% of diet DM, respectively). Sucrose and sunflower oil replaced barley grain in the diets. Milk production and composition were analyzed on days 18, 36 and 54 on treatments, and ruminal fermentation parameters and milk FA profile on days 18 and 54. Dry matter intake, milk fat, protein and lactose concentrations were not affected by treatments. The SU increased (P<0.1) milk yield compared with CON whereas the SU and SO led to higher (P<0.01) 4% fat-corrected milk yield. The SO and SU diets increased (P<0.1) the milk lactose yield more than the CON diet. We observed a higher (P<0.01) content of ruminal acetate in the CON diet, and also higher (P<0.05) valerate content with the SU and SO+SU diets compared with the CON diet. Feeding SU and SO+SU tended to decrease (P<0.05) ruminal pH, yet goats fed SU had the highest (P<0.01) ruminal propionate concentration. There was no effect of diet on ruminal butyrate, isovalerate and ammonia-N concentrations. The acetate:propionate ratio substantially decreased (P<0.05) with the SU compared with the CON and SO+SU, and did not change with SO diet. Feeding sunflower oil increased (P<0.01) plasma triglyceride and cholesterol concentrations compared with feeding the CON and SU diets. The majority of fatty acids measured were not affected by inclusion of sucrose compared with the CON diet. The SO and SO+SU diets increased the proportion of total trans-C18:1, total CLA, and C18 family in milk fat compared to CON or SU diets. The current study implies that replacing barley grain with sucrose may improve milk yield and modify ruminal fermentation pattern in dairy goats. Moreover, sucrose did no alter ruminal fatty acid biohydrogenation pathways and following milk fatty acid composition when goats were fed with a combination of unsaturated fat and sugar.