Nitrogen fractions of some locally available proteinaceous feedstuffs

Eleven samples of proteinaceous feed ingredients comprising of one animal protein (meat and bone meal) and five each of vegetable proteins and pulse chuni were analyzed for the composition of total nitrogen, buffer insoluble nitrogen, protease (Streptomyces griseus) insoluble nitrogen and acid detergent insoluble nitrogen (ADIN). The buffer insoluble N (Nx6.25) value (%) of meat and bone meal (65.59) and black gram chuni (63.28) were observed to be significantly higher followed by ambadi cake, and that of safflower cake was the least. Fraction of feed N resistant to protease was found to be significantly high in ambadi cake (47.46%) as compared to other feed samples, and groundnut cake being the least (12.97%). The ADIN content (%) of groundnut cake was observed to be significantly lower (5.54) followed by other samples with a maximum ADIN content in ambadi cake. The ADIN content of green gram chuni was similar to that of black gram chuni. Rumen escape protein value (%) of ambadi cake (27.52) and meat and bone meal (26.41) was found to be significantly high as compared to other feedsamples. The values were lower for groundnut cake and safflower cake. Rapid rumen solubalisable N expressed as per cent rumen degradable N was significantly high for safflower cake (86.76) followed by groundnut cake, ambadi cake and field bean. Black gram chuni, bengal gram chuni, meat and bone meal, cotton seed cake and safflower cake were having similar value for rapidly solubalisable N fraction. It is concluded that various iso-nitrogenous feed sources can have wide variation in rumen degradation pattern thus presenting different N fractions at duodenal level.