Fate and Transformation of Nitrogen from 15N-Labelled Rice Straw After Feeding Goat

Three goats were fed with 15N-labelled rice straw to study the characteristics of digestion, assimilation, transformation and excretion of C and N compounds from rice straw. It was shown that the amount of 15N transformed into the bodies of the two slaughtered goats accounted for 38.5 and 23.6% of the total amount of 15N deposition of the experimental diet taken by each goat. The 15N excreted through the feces and urine for the three goats accounted for 34.8, 33.2 and 33.9% of the total amount of 15N deposition in the feed of the 3 goats. The recovery of total 15N for the two slaughtered goats were 73.3 and 57.5%, with the corresponding rates of 15N loss 26.7 and 42.5% respectively. The digestibilities of total amino acids for Goats 1 and 3 were 68.7 and 54.0%, and the digestibilties of carbohydrates for the two goats were 74.8 and 67.7% respectively.