Search PubMed⌕ Search

Biomedical subjects

D G Armstrong

Publications and source records attributed to D G Armstrong.

At least 163 records · Page 9Linked to original sources
PubMed1978

The effect of partially replacing urea nitrogen with protein N on N capture in the rumen of sheep fed a purified diet.

1. The influence of replacing 10% of the urea nitrogen in a purified diet with casein, maize gluten or white fish meal on the efficiency of conversion of dietary-N into microbial N was examined using sheep equipped with rumen fistulas and duodenal re-entrant cannulas. 2. Total nitrogen (TN), non-ammonia nitrogen (NAN) and amino acid nitrogen (AAN) flowing to the proximal duodenum were significantly higher (P smaller than 0.05) when maize gluten was added to the diet, and this appeared to be due to an increased efficiency of microbial protein production. 3. Pepsin secretion was not significantly different between treatments and the daily amount of pepsin N flowing to the proximal duodenum was very small (40-53 mg). The peak of pepsin activity in duodenal digesta was reached 6-8 h after feeding. 4. The possible practical implications of the results are discussed.

Amino Acids↗
PubMed1977

Activity of 3beta-hydroxyteroid dehydrogenase in the postovulatory follicle of the domestic fowl (Gallus domesticus).

The activity of delta5-3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the postovulatory follicle (POF) of the domestic hen was studied; it declined rapidly during the first 15 h after ovulation and then fell gradually until 52 h when there was no detectable activity. Comparison of 3beta-HSD and glucose 6-phosphate dehydrogenase activities in the theca and granulosa cells indicated that the changes in enzymatic activity can be attributed to the thecal component; the enzyme activity in granulosa cells was stable up to 35 h after ovulation. The results appear consistent with the hypothesis that the POF is a source of steroid hormones.

Animals↗