Nitrogen rumen

Waghom GC, Stafford KJ. Gas production and nitrogen digestion by rumen microbes from deer and sheep. New Zealand Journal Agricultural Research. 1993 36 493-497. 

Production of HA from nitrate as the sole nitrogen source by unknown soil bacteria was demonstrated as early as 1928 and 1931, and was confirmed in 1932 by the use of known pure bacterial cultures. Later, HA was suggested to be an intermediate in the in vitro reduction of nitrate by sheep rumen bacteria . 

Lactosylurea. Lactosylurea is formed under acid conditions from lactose and urea (McAllan et al 1975) conversion of 75% of the lactose was achieved. Widell (1979) described a method for its preparation from whey and urea intended for feeding to ruminants. Ruminants can utilize nonprotein nitrogen compounds for protein synthesis, but urea itself can cause difficulties through too rapid decomposition to ammonia by the rumen enzymes. Lactosylurea appears to meet the requirements for satisfactory palatability, controlled nonprotein nitrogen release, and low toxicity. 

In most species the level of pancreatic ribonuclease is quite low. Its function presumably is the digestion of exogenous RNA in the diet. In ruminants there is very much more of the enzyme, and Barnard (12) has concluded that the primary purpose of pancreatic ribonuclease is digestion of the RNA of the bacteria in the rumen rather than of the dietary RNA. The reutilization of the nitrogen and phosphorus of this... 

As with M. ruminantium, Methanobacterium strain MOH can utilize neither peptides nor amino acids as a nitrogen source replacing NH4 (Figures 5 and 7). NH4 utilization is essentially the same (Figure 8) when NH4 is the nitrogen source or when rumen fluid, amino acids, yeast extract, and Trypticase are present in the medium as complex sources of nitrogen that would be utilized in place of NH4 by most heterotrophic bacteria other than some rumen carbohydrate-fermenting anaerobes (11). 

MOH in media with as nitrogen source and with complex nitrogen sources added. Medium was the same as the basal shown in Figure 5 but with 12.2 mM sodium acetate and 2 mM (NH )2SO added or the same medium but with 20% of clarified rumen fluid, 0.5% of Trypticase, 0 2% of yeast extract and the mixture of i.-amino acids added (Figure 7). Ammonia fixed was determined as indicated in... 

Figure 1. Time course of the rumen fermentation. Solid lines show nitrogen in the solids fraction for 5 g/liter glucose (solid circles) and for 5 g/liter sugar beet pulp (open circles). The high initial value for sugar beet pulp represents its protein content as received.

Lon anemia (Fe deficiency) in humans is common, but is due to low availability to plants rather than low amounts in the soil. Molybdenum deficiency, which prevents microbial nitrogen fixation, and cobalt deficiency in Australian sheep that prevents rumen bacteria from synthesizing vitamin B12, have been reported in Australia. Phosphate deficiency that led to weak bones in grazing animals was reported in Norway. 

The aspen silage was extremely low in nitrogen (0.1% DM basis) so that nitrogen deficiency in the inoculum from animals fed this material was probably a major factor in reducing the cellulolytic activity of the rumen microflora. 

Nitrogen. In this discussion nitrogen as a supplement will be discussed only in relation to its effect on rate and extent of breakdown of lignocellulose in the rumen and will take no account of nitrogen requirements of the ruminant per se. 

In the ruminant animal the availability of nitrogen for breakdown of lignocellulose in the rumen is mediated by both feed and physiological factors. Nitrogen is available to the microflora immediately from the feed and in the form of urea which is recycled from the blood stream and enters the rumen in the parotid saliva, and also directly from the blood through the rumen wall. Thus, over short feeding periods of a few days... 

The chemical nature of crude protein in feedstuffs is the primary factor determining how rapidly it is degraded to ammonia or escapes microbial degradation. To compare feedstuffs, feed nitrogen can be divided into NPN, true protein, and unavailable fractions, which Pichard and van Soest (1977) labeled as the A, B, and C fractions, respectively (Fig. 18.3). The A fraction is rapidly attacked by rumen bacteria and converted to ammonia. Approximately 20% of the crude protein in SBM is in the A fraction and is degraded in the rumen at a rate of 300%/h (NRC, 1996). In contrast, a more undegradable protein source like distillers grains has 6% of the crude protein in the A fraction. 

The unavailable or C fraction nitrogen is estimated by measuring the amount of acid detergent insoluble protein (van Soest, 1991). This fraction is assumed to have zero availability in the rumen and small intestine, and thus has no nutritional value. SBM is a highly digestible protein source with only 2% of the protein in the C fraction (NRC, 1996). In contrast, many slowly degraded protein sources have 10—20% of the protein in the C fraction. 

Table 18.11. Effect of Concentration of Dietary Corn and Rumen Ph on Nitrogen Disappearance From Dacron Bags...

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