The biuretolytic activity of the ruminal flora of sheep fed practical rations containing biuret

Abstract

The biuretolytic activity of the ruminal flora which developed in the ingesta of Merino sheep in response to feeding biuret with practical rations was demonstrated. The activity was determined by measuring the rate of disappearance of biuret in an in vitro fermentation system. Biuret was determined by a specific, semi-micro, colorimetric method based on the formation of a yellow nickel-biuret complex and adapted for use with ruminal fluid. The activity was evoked only when biuret was included in diets of poor quality teff hay with or without maize meal. With ruminal ingesta from sheep fed teff hay and biuret the activity was low, but when maize meal was given in addition the activity was about three times as high, and sufficient to account for the disappearance of up to 16-4 g daily in Merino sheep with a volume of ruminal ingesta of 6 1. The course of development of biuretolytic activity is discussed in relation to retention of biuret-nitrogen.

Adaptation of the ovine ruminal flora to biuret

“…In view of these findings a detailed examination of the biuretolytic activity of ruminal ingesta of sheep on very low, medium and somewhat higher protein rations was conducted to determine the adaptation period and to establish any relationship between the quality of the basal ration and the length of this period. Furthermore, Gilchrist et al (1968) recorded a higher activity from sheep which received a supplement of maize meal in addition to biuret. This could have been due to either the starch and/or the protein in the maize meal.…”

“…_"rpr>f)T)TjC l TTON which influence it is needed for the proper design of nutritional experiments with biuret. A positive response by ruminants to supplemen-The work of Gilchrist et at. (1968) clearly demontation of their rations with biuret as a non-protein strated that the breakdown of biuret was brought nitrogen source has often been observed to be about by the micro-organisms in the ingesta of the preceded by a period in which the benefit was rumen.…”