Effect of dietary energy source and level on serum growth hormone, insulin-like growth factor 1, growth and body composition in beef heifers

• Published in: Journal of animal science Vol. 66; no. 11; p. 2916
• Main Authors: Houseknecht, K.L, Boggs, D.L, Campion, D.R, Sartin, J.L, Kiser, T.E, Rampacek, G.B, Amos, H.E
• Format: Journal Article
• Language: English
• Published: United States 01.11.1988
• Subjects: ALMIDON; AMIDON; Animals; BEEF CATTLE; BLOOD SERUM; Body Composition - drug effects; Body Weight - drug effects; BOVIN DE BOUCHERIE; CARCASS COMPOSITION; Cattle - growth & development; COMPOSICION DE LA CANAL; COMPOSITION DE LA CARCASSE; CONTENIDO DE FIBRAS; CRECIMIENTO; CROISSANCE; Dietary Carbohydrates - pharmacology; Dietary Fiber - pharmacology; Energy Metabolism; ENERGY SOURCES; Female; FIBRE CONTENT; FUENTE DE ENERGIA; GANADO DE CARNE; GENISSE; GROWTH; Growth Hormone - blood; HEIFERS; HORMONAS PITUITARIAS; HORMONE HYPOPHYSAIRE; Insulin-Like Growth Factor I - blood; NOVILLA; PITUITARY HORMONES; SERUM SANGUIN; Somatomedins - blood; SOURCE D'ENERGIE; STARCH; SUERO SANGUINEO; TENEUR EN FIBRES
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/jas1988.66112916x

Effects of fiber vs starch energy supplements on endogenous growth hormone (GH), insulin-like growth factor (IGF-1) and animal performance from weaning to breeding age were evaluated in 18, 9-mo-old beef heifers. Heifers had ad libitum access to wheat silage plus an average daily supplement intake of 1) 4.08 kg corn-soybean meal (SBM) (high energy-starch, HS), 2) 4.54 kg soyhulls (SH)-SBM (high energy-fiber, HF) or 3) 1.36 kg SH-SBM (low energy-fiber, LE). Serum samples were collected via jugular puncture every 10 d and were analyzed for IGF-1 by RIA. On d 45 and d 176, four heifers per treatment were fasted 18 h and serial blood samples collected via jugular cannulas every 15 min for 6.5 h. Arginine (.5 g/kg BW) was administered intravenously (ARG) to induce release of GH, and four additional samples of blood were collected. Samples were analyzed by RIA for GH. Mean fasted GH (6.4 +/- .4, 8.3 +/- .4 and 13.8 +/- .4 ng/ml for HS, HF and LE, respectively) varied with energy source and level (P less than .01). Mean GH following ARG was higher (P less than .01) in heifers receiving LE (46.2 +/- 4.7) than in those receiving HS and HF (23.5 +/- 4.4 and 24.1 +/- 4.6 ng/ml). Basal GH concentration and peak amplitude were higher (P less than .05) in LE than in HS and HF treatments. Diet did not influence number or frequency of GH peaks.