Effect of Graded Levels of Niacin Supplementation on Total Mixed Ration Containing Different Non-Protein Nitrogen Sourcesin vitro

The present study was undertaken to study the effect of varying levels of niacin supplementation(0, 200, 400 and 600 ppm, respectively) on low urea based total mixed ration (TMR)replacing 10% of total crude protein (CP) of ration with different non protein nitrogen (NPN) sources by in vitro gas production technique. All the rations were iso-nitrogeneous in nature. On the basis of higher partition factor, neutral detergent fibre degradability (NDFD%), organic matter degradability (OMD%), microbial mass production and efficiency of microbial mass productionfrom different NPN sources. Supplementation of varying levels of niacin in low urea based TMR did not have any significant effect on microbial mass production and its efficiency. The in vitro pH and NH3 concentration was significantly (P<0.05) reduced at 600ppm level of niacin supplementation. The total volatile fatty acids (TVFA) concentration was significantly higher (P<0.05) in control TMR and lowest in uromol based TMR. Niacin supplementation produced significantly higher (P<0.05) TVFA at 200ppm level and lowest (P<0.05) at 600ppm in TMR. It can be concluded that slow release urea seems to be better option than urea and uromol as NPN supplement in the diets of ruminants when low (10% of total CP) urea based TMR is to be prepared.