In vitro study of Nigella sativa meal as protein source and its combination with the readily available carbohydrates for ruminant diet

Nigella sativa meal (NSM) is a waste generated from the oil processing industry of black cumin or known as habbatussauda. NSM contains high crude protein that can be used by ruminant. The purpose of this study was to evaluate the quality of crude protein of NSM in rumen and its combination with the readily available carbohydrates (RAC). This study was began by observing ammonia (NH3) concentration from NSM and volatile fatty acid (VFA) concentration from several types of RAC that were incubated in rumen fluid in vitro. Then followed by evaluation of rumen fermentability of diets containing NSM that was combined with different types of RAC. This study used a complete randomized design with 3 treatments and 5 replications. The treatments were differentiated by the type of RAC that was used in the diet, which consisted of pollard (P), rice bran (R), and corn (C). The level of NSM is equated in each treatment. Diet consisted of forage and concentrate with the ratio of 30: 70. The results showed that NSM has high NH3 concentration in the rumen, especially in the first 4 hours and after 6 hours of incubation time in rumen fluid in vitro. The combination of NSM in rations containing corn significantly suppressed NH3 concentration (P<0.05). In addition, NSM and its combination with corn in the diet produced microbial protein synthesis higher (9.66 mg 10ml(-1)) compared with another treatments R (9.64) and P (7.85). The use of NSM as much as 20% in rations and its combination with the RAC derived from corn can optimize the use of NSM as a source of feed protein in ruminants by maximize the utilization of NH3 and VFA to encourage the production of microbial protein synthesis that were important for ruminants.