The inter-relationships of individual proteins and carbohydrates during fermentation in the rumen of the sheep. I. The fermentation of casein in the presence of starch or other carbohydrate materials

Abstract

1. The metabolic interactions of casein and starch or other carbohydrates are measured by estimating the concentrations of volatile fatty acids, ammonia, lactic acid and amino acids in the rumen after administering the protein and carbohydrate supplements alone or together.2. The ammonia concentration is reduced (i.e. its utilization is probably increased), by the carbohydrate materials; levan and starch achieve this slightly more effectively than glucose or xylan and the effect of cellulose is very slight.3. Under conditions when the normal ration fed is not of high quality a small supplement of casein stimulates the rate of fermentation of starch and other carbohydrates.4. The findings indicate that the best utilization of protein supplements is probably obtained when a carbohydrate is also present that can be fermented at a comparable rate, conditions which stimulate microbial synthesis in the rumen.

Source of Nitrogen for Rumen Microbes

“…This is also in agreement with results of Meiske et al (19661, Bloomfield et al (19581, Johnson (19761, Thomsen &NeimannSorensen (1973, andRao (1977). A number of workers (Lewis & McDonald, 1958;Lewis, 1962;Purser & Moir, 1966) found that cellulose was a poorer source of energy for the ruminal microflora when ammonia was the primary nitrogen source. The digestibility of starch with urea was maximum (64%) at 1.00% nitrogen, and then it declines (47.70%) at 2.15% nitrogen.…”

266 Evaluation of peri-partum supplementation of methionine hydroxy analog on cow-calf performance.

“…Often the limiting factor in MPS is the availability of energy from fermentation with its rate of production similar to the rate at which the microbes can utilize it. Lewis and McDonald (1958) and Phillipson et al (1962) revealed that the non-structural carbohydrates (sugars and starches) were efficient in decreasing ruminal ammonia concentrations by increased MPS; subsequently, Stern et al (1978), identified that having greater ratios of structural carbohydrates (pectins, cellulose, and hemicellulose) compared to non-structural carbohydrates actually increased ammonia concentrations thereby decreasing MPS. Russell et al (1992) separated the rumen microbes into 2 groups, those that ferment structural carbohydrates, grow slowly, and use ammonia as a primary N source, and those that ferment non-structural carbohydrates, grow rapidly, and utilize ammonia, AA, and peptides as a N source.…”

Chemical composition of pastures in relation to grass tetany in beef breeding cows

“…Johns (1955b) found lower volatile-fatty acid levels and higher ammonia levels in the rumen of sheep when fed winter as compared with summer pasture, suggesting such an effect. It has been further shown, by various authors, that readily fermentable carbohydrates, such as sugar and starch, have a marked effect in reducing the high rumen ammonia concentrations resulting from nitrogenous feeds and improving the utilisation of protein (e.g., Lewis and McDonald 1958;Reis and Reid 1959;Chalmers and Ogilvie 1960;Boda, Tomas, and Kona 1961;Tagari, Dror, Ascarelli, and Bondi 1964;Robertson and Hawke 1965). This once again emphasises the importance of a balanced protein: carbohydrate ratio.…”