caa a22 4500 388060115 CHVBK 20180307125118.0 cr unu---uuuuu 161130e199812 xx s 000 0 eng 10.1017/S1357729800032987 doi S1357729800032987 pii (NATIONALLICENCE)cambridge-10.1017/S1357729800032987 Effects of growth hormone administration on the body composition and hormone levels of genetically fat sheep [Elektronische Daten] Coopworth sheep selected for low (lean) or high (fat) backfat have large differences in plasma GH profiles. Fat genotype ram lambs (5 months old) were treated with growth hormone (GH) to simulate the plasma GH profiles of lean sheep and investigate whether exogenous GH could modify carcass fatness. For 77 days, bovine GH was administered at 25 Uglkg live weight per day either as a single, daily subcutaneous bolus (fat bolus) or via portable pulsatile infusion pumps (fat pump) which delivered GH solution at 90-min intervals into a jugular catheter. Measurements of body composition were made by computed tomography (CT) and ultrasonic scanning during the trial, with linear carcass measurements and proximate analysis undertaken at the end of the experiment. Before treatments began, mean plasma GH levels were lower (P < 0·01) in fat control (0·34 ugll) than in lean lambs (1·1 μg/l). Several weeks after the start of the trial, mean plasma GH had increased in both fat bolus (1·2 μg/l) and fat pump (0·45 μg/l) treatment lambs with major changes in the pulsatility relative to the fat control lambs. Although these changes were maintained in the fat bolus lambs, by the end of the trial there was no significant difference in mean plasma GH between fat pump and fat control sheep. Throughout the trial, plasma 1GF-1 levels were higher in fat bolus, fat pump and lean lambs than in fat control lambs. Analysis of body composition data over the GH treatment period revealed that the slope of the allometric equation for total fat relative to empty body weight was lower in the fat bolus lambs (1·07) than in the lean lambs (1·50) with fat control and fat pump treatment lambs intermediate (1·30 and 1·36, respectively). Subcutaneous fat was later maturing in lean lambs than in fat control and bolus treatment lambs when regressed against total fat, with the fat pump treatment lambs being intermediate. Linear carcass measurements revealed changes due to GH administration in the distribution of subcutaneous fat and eye muscle dimensions. It is concluded that sheep from the fat genotype show physiological responses to exogenous GH. Increasing plasma GH levels of fat sheep increased plasma IGF-1 and had variable effects on carcass fatness. The change in body composition may be affected by the mode of administration of exogenous GH. Copyright © British Society of Animal Science 1998 body composition nationallicence computed tomography nationallicence sheep nationallicence somatomedin nationallicence somatotropin nationallicence ultrasonography nationallicence Francis S. M. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand Jopson N. B. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand Littlejohn R. P. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand Stuart S. K. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand Veenvliet B. A. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand Young M. J. Animal and Veterinary Sciences Group, PO Box 84, Lincoln University, New Zealand Suttie J. M. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand Animal Science Cambridge University Press 67/3(1998-12), 549-558 1357-7298 67:3<549 1998 67 ASC https://doi.org/10.1017/S1357729800032987 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S1357729800032987 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Francis S. M. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand NATIONALLICENCE 700 1- Jopson N. B. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand NATIONALLICENCE 700 1- Littlejohn R. P. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand NATIONALLICENCE 700 1- Stuart S. K. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand NATIONALLICENCE 700 1- Veenvliet B. A. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand NATIONALLICENCE 700 1- Young M. J. Animal and Veterinary Sciences Group, PO Box 84, Lincoln University, New Zealand NATIONALLICENCE 700 1- Suttie J. M. AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand NATIONALLICENCE 773 0- Animal Science Cambridge University Press 67/3(1998-12), 549-558 1357-7298 67:3<549 1998 67 ASC CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge