Effect of dietary fat on uptake of lysine, phenylalanine, leucine and methionine by bovine mammary tissue slices in vitro
- Univ. of Georgia, Athens (USA)
- Langston Univ., OK (USA)
Four mature Holstein cows in late lactation were blocked in two groups based on milk production, in a 2x2 reversal with 21-day periods, and fed: (A) control diet; (B) A plus 1 kg/day tallow. Cows were fed sorghum silage ad libitum. Blood samples were collected from the jugular vein on day 15, 17, and 19 of each period. Fat did not effect DM intake or milk yield, however milk CP yield was 20% lower. Plasma lipids increased 33.6%, glucose decreased 9% and insulin/glucagon ratio decreased 21.2% in cow fed fat. After period two, cows were slaughtered and mammary tissue sampled for incubation in Krebs Ringer bicarbonate buffer containing 22 AA at arterial concentration and .225 {mu}Ci/ml of {sup 14}C-labelled L-Leu, L-Phe, L-Lys or D/L Met. Dietary fat decreased tissue AA uptake rate by 21.2%. Uptake was 4.8, 10.3, 17.8 and 2.4 {times} 10{sup {minus}3} {mu}M/min/gm of tissue DM for Phe, Lys, Leu and Met, respectively. Results suggest that dietary fat may decrease milk protein synthesis by lowering the rate of AA uptake.
- OSTI ID:
- 5102196
- Journal Information:
- Journal of Dairy Science; (USA), Vol. 72:8; ISSN 0022-0302
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMINO ACIDS
BIOCHEMICAL REACTION KINETICS
FATS
CARBON 14 COMPOUNDS
COWS
DIET
INSULIN
LEUCINE
LYSINE
MAMMARY GLANDS
METHIONINE
PHENYLALANINE
TRACER TECHNIQUES
ANIMALS
BODY
CARBOXYLIC ACIDS
CATTLE
DOMESTIC ANIMALS
DRUGS
GLANDS
HORMONES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LIPOTROPIC FACTORS
MAMMALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PEPTIDE HORMONES
REACTION KINETICS
RUMINANTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques