
%0 Journal Article
%A Leibholz, J 
%A Hartmann, PE 
%T Nitrogen metabolism in sheep. I. The effect of protein and energy intake on the flow of digesta into the duodenum and on the digestion and absorption of nutrients
%J Australian Journal of Agricultural Research
%D 1972/12/01
%V 23
%N 6
%P 1059-1071
%K 
%R https://doi.org/10.1071/AR9721059
%U https://www.publish.csiro.au/paper/AR9721059 
%X The digestion of organic matter, nitrogen, and sulphur was measured in sheep fitted with re-entrant duodenal cannulae. The sheep were given 1.4, about 16, or 30 g of nitrogen per 24 hr from barley roughage with or without a nitrogen supplement of lucerne, wheat gluten, or casein. A further diet supplied 16.1 g of nitrogen per day but consisted of 83 % low-quality roughage compared with 50% in the other diets. The flow of digesta to the duodenum varied from 4.4 to 6.8 1. per 24 hr with dry matter intakes of 480&ndash;800 g per 24 hr. The sheep were fed hourly and watered continuously, and there was a more than 10-fold variation in the flow of digesta to the duodenum over 2-hr collection periods. The digestibility of organic matter was lower for the diet supplying 1.4 g of nitrogen per day than for the other diets. Between 77 and 96 % of the apparent digestion of organic matter occurred before the duodenum. In the sheep given 1.4 g of nitrogen per 24 hr, the flow of nitrogen to the duodenum was 4.8 g per 24 hr, while in the sheep given about 16 g of nitrogen daily the flow of nitrogen to the duodenum was 8.4&ndash;11.8 g per 24 hr. Only 35 % of the dietary intake of nitrogen reached the duodenum in the sheep given 30 g of nitrogen daily. The sheep given the diet containing 83 % low-quality roughage showed a lower retention of nitrogen than those given the other diets of similar nitrogen content. Between I and 9 % of the flow of nitrogen to the duodenum was in the form of ammonia. The flow of sulphur to the duodenum was between 33 and 55% of the dietary intake, while 72-99% of the apparent digestion of sulphur occurred before the duodenum. The digestibility of dietary sulphate sulphur was greater than that of the sulphur found in lucerne. 
