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Title: PATTERNS OF NUTRIENT INTERCHANGE AND OXYGEN USE AMONG PORTAL-DRAINED VISCERA, LIVER, AND HINDQUARTERS OF BEEF STEERS FROM 235 TO 525 KG BODY WEIGHTS.

Author
item EISEMANN, JOAN - 5438-01-07
item HUNTINGTON, GERALD - CONSULTANT
item CATHERMAN, DANIEL - 5438-01-07

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/12/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Changes in nutrient use by body tissues are responsible for changes in body composition with age. The ability to alter nutrient use by body tissues in food-producing animals can lead to improved animal efficiency and more healthful products. Interorgan exchange of nutrients provides information on changes occurring in both visceral and peripheral tissues and forms a framework to address questions of cellular mechanisms regulating nutrient use. Our data show the complementary metabolic changes occurring between the liver and peripheral tissues with regard to nitrogen and energy use. Quantitative information on nutrient use by body tissues can be used to evaluate models of biological systems that probe regulatory aspects of metabolism.

Technical Abstract: Objectives were to quantify changes in supply and use of nutrients and oxygen by steers as they grew from 235 to 525 kg BW. Weight of steers at the first of two samplings for each of 3 groups was 236, 319 and 445 kg, respectively. Steers were killed after the second sampling. Tissue weights and hindquarters (HQ) content of fat, protein, and ash were measured. Blood flow, oxygen uptake, and net uptake or release of metabolites were regressed against functions of BW**.75 to assess changes during growth. Blood flow in all tissues except liver, and oxygen use by all tissues decreased per unit tissue weight as the steers aged. Changes with age per unit liver weight were: decreased uptake of propionate and lactate; increased uptake of alpha-amino N and glutamine; decreased production of urea and glutamate; and increased production of acetate and beta-hydroxybutyrate. Glucose production per unit liver weight was constant. Changes with age per unit HQ weight were: increased uptake of glucose but decreased uptake of alpha-amino N and glutamate; decreased release of lactate and increased release of glutamine. Weight of the portal-drained viscera (PDV) increased from 91 to 97 g/kg EBW as BW increased from 236 to 522 kg. PDV fat increased from 375 to 552 g/kg PDV tissues. Liver decreased from 16 to 12 g/kg EBW. HQ decreased from 286 to 266 g/kg EBW. HQ protein was 200, 197 and 200 g/kg HQ tissue for Group 1, 2, and 3, respectively. Corresponding fat was 131, 182 and 177 g/kg HQ tissue.