Digestion of proteins of varying degradability in sheep. 1. Fermentation in and rate of passage from the reticulorumen.

Abstract

Sugarbeet pulp, citrus pulp, sugarbeet molasses and minerals and vitamins were mixed with different amounts of groundnut expeller, potato protein, peas or dried brewers' grains to give 6 concentrates with protein solubility from 7 to 51%. The concentrates (600 g daily) were given with rye grass (300 g daily) to 2 Texel wethers weighing about 70 kg with a cannula in the dorsal rumen sac. With increasing degradability of protein, rumen fermentation was less stable, the diurnal variation and content of ammonia in rumen fluid were increased, the ratio of non-glucogenic to glucogenic volatile fatty acids decreased and the dilution rate of rumen fluid increased. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Digestion of proteins of varying degradability in sheep. 2. Amount and composition of the protein entering the small intestine.

“…The ex tent of degradation is determined by degradability and the time interval the prote ins are subjected to rumen fermentation. Under the present experimental condi tions ( van Bruchem et al, 1985) the less easily degradable rations PP and BG were retained in the forestomachs slightly longer. Dilution rates of the liquid phase amounted to about 0.10 h _1 .…”

“…NHj-N was highest with groundnut expeller (GE) and peas (PE) containing the more easily degradable proteins, corresponding with the ammonia levels in the ru men. Of the microbes isolated from the rumen (van Bruchem et al, 1985) and duo denum scanning electron micrographs are presented in Fig. 1.…”

“…The details of the experimental conditions are described by van Bruchem et al (1985). With groundnut expeller (GE), potato protein (PP), dried breweries grains (BG) and peas (PE) as the main protein sources concentrate mixtures were com posed of which the rumen protein degradability varied.…”

“…GE and PP were fed at a higher (2) and lower (1) protein level, BG and PE only at the lower (1) level. The composition of the concentrates and the experimental design were as given by van Bruchem et al (1985).…”

“…From samples collected from the ventral rumen sac (van Bruchem et al, 1985) and the cranial duodenum, microbes were isolated by differential centrifugation (550-70 000 g) with a MSE superspeed 65 centrifuge at 4 °C. The pellet was washed twice with buffer solution according to the method described by Meyer et al (1967).…”