Effects of different dietary nitrogen sources on duodenal chyme parameters in yearling sheep

T. Slavov*, V. Radev, R. Mihaylov, I. Varlyakov

Department of Morphology, Physiology and Animal Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. A physiological trial was conducted to evaluate the effect of diet supplementation with non-protein nitrogen compounds Optigen and urea through determination of duodenal chyme pH, volatile fatty acids and ammonia concentrations in yearling sheep. The experiment was carried out with 6 yearling sheep, Pleven Blackhead × Suffolk crosses. The experiment was conducted in three periods – control and two experimental. During the control period, the ration of animals consisted of 0.700 kg barley and 1.000 kg meadow hay. During the first experimental period, the ration was supplemented with 0.012 kg Optigen, and during the second experimental period – with 0.0106 kg urea. Both supplements (Optigen and urea) did not have an effect on duodenal chyme pH and a trend towards slight increase in postprandial hours was noted. The addition of Optigen led to statistically significantly increased volatile fatty acid (р<0.01) as early as the first hour and peak values 2.5 h after feeding, whereas urea supplementation resulted in minimum elevation only 2.5 hours after feeding. The most pronounced effect of Optigen supplementation was observed on duodenal chyme ammonia levels, in particular 2.5 hours after feeding (p<0.001 vs control period and p<0.01 vs dietary urea supplementation).