Metabolism of Purine Derivatives and Microbial Nitrogen Supply in Sheep fed Different Protein Supplements

Abstract

Dipu, M. T., Singh, P., Verma, A. K. and Mehra, U. R. 2008. Metabolism of purine derivatives and microbial nitrogen supply in sheep fed different protein supplements. J. Appl Anim. Res., 34: 65–70. To study the use of purine nitrogen index (PNI) as an indicator of nitrogen utilization efficiency in sheep fed on deoiled groundnut cake (gr I), deoiled mustard cake (gr II), deoiled soybean meal (gr III) or cotton seed cake (gr IV), eight adult Muzaffarnagari sheep were fed maintenance diets comprised of wheat straw and concentrate mixture (50:50) into two sets of 4x4 Latin Square Design. The purine derivatives (PD) excretion, microbial nitrogen (MN) supply, purine nitrogen index (PNI), concentration of plasma allantoin, PD and tubular load of total PD were higher (P<0.05) in group III compared to group II. The PNI responded to dietary treatments and the effect was more pronounced at 6 h post feeding. The relationship between PNI in the spot samples collected 6 h post feeding and the daily nitrogen balance (P<0.05) was the highest (R2=0.73). Thus, it may be deduced that the PNI could be used as an indicator for assessing efficiency of dietary nitrogen utilization. The collection of spot urine samples at 6 h post feeding represented better PNI of total daily urine collection, so it could be used effectively under farm conditions.