Effects of roasting on ruminal nutrient degradability of sunflower seed

A study was conducted to determine the effects of roasting sunflower seed using heated particulate medium (heated salt at 250 °C, 60 s contact of salt and sunflower seed and 120 s holding time) on crude protein (CP) fractions, ruminal dry matter (DM) and CP degradabilities, and ruminal disappearance of amino and fatty acids. Two ruminally fistulated cows were used in a randomised complete block design. Roasting of sunflower seed decreased (P (less than) 0.05) soluble protein and increased (P (less than) 0.05) neutral detergent-insoluble protein with little effect on acid detergent-insoluble protein. Results of the in situ nylon bag study showed that roasting decreased (P (less than) 0.05) ruminal degradability of DM and CP and increased (P (less than) 0.05) ruminal undegraded CP of sunflower seed. Roasting increased (P (less than) 0.05) intestinal digestibility of ruminal undegraded protein. Ruminal disappearance of all amino acids (following 12 h of incubation) was greater (P (less than) 0.05) for raw than for roasted sunflower seed. Similar results were also observed for ruminal disappearance of fatty acids. It was concluded that roasting of sunflower seed using heated salt decreased ruminal nutrient degradabilities and thus increased the concentrations of amino acids and polyunsaturated fatty acids available for digestion in the small intestine.