caa a22 4500 386322309 CHVBK 20180307111630.0 cr unu---uuuuu 161130e198805 xx s 000 0 eng 10.1079/BJN19880055 doi S0007114588000571 pii (NATIONALLICENCE)cambridge-10.1079/BJN19880055 The action of the β-agonist clenbuterol on protein and energy metabolism in fattening wether lambs [Elektronische Daten] 1. Five Greyface wethers (42-45 kg) fed on various fixed amounts of dried grass pellets (either approximately 1·3 times maintenance or 2 times maintenance) by means of belt-type continuous feeders were housed in opencircuit respiration chambers for periods of 45 d. Between days 15 and 35 they received daily oral doses of 1·5 mg of the β-adrenergic agonist clenbuterol (adsorbed on to the feed). Continuous energy and nitrogen balance measurements each of 5 d duration were conducted throughout the chamber confinement. 2. On six occasions (twice during the 15 d pre-clenbuterol period, on days +4, +11 and +18 of clenbuterol administration and once during the post-treatment period) animals were infused with [l-14C]leucine to determine the rates of leucine oxidation and the amounts of leucine available for protein synthesis. 3. Clenbuterol administration caused a marked increase in N retention (2-3 g N/d; P < 0·001) throughout the 20 d treatment period. It also increased (P < 0·001) the energy expenditure of the animals (on average by 1·1 MJ/d over the first 5 d, compared with immediate pretreatment values, and 0·6 MJ/d over the 20 d period, compared with the mean of pre- and post-treatment control values). The effect of treatment was calculated to result, on average, in the daily retention of 19 (SE 1·5) g more protein and 30 (SE 5·5) g less fat. 4. During clenbuterol treatment leucine oxidation was reduced (P < 0·01). However, values for the amounts of leucine available for protein synthesis were equivocal, with an increase (P < 0·001) on day 11 of treatment, but no change on days 4 and 18. 5. Withdrawal of the clenbuterol resulted in rapid alterations of N and energy metabolism towards those expected of control animals of that weight. Copyright © The Nutrition Society 1988 MacRae J. C. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB Skene Pat A. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB Connell Alexmary Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB Buchan Vivien Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB Lobley G. E. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB British Journal of Nutrition Cambridge University Press 59/3(1988-05), 457-465 0007-1145 59:3<457 1988 59 BJN https://doi.org/10.1079/BJN19880055 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1079/BJN19880055 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- MacRae J. C. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB NATIONALLICENCE 700 1- Skene Pat A. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB NATIONALLICENCE 700 1- Connell Alexmary Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB NATIONALLICENCE 700 1- Buchan Vivien Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB NATIONALLICENCE 700 1- Lobley G. E. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB NATIONALLICENCE 773 0- British Journal of Nutrition Cambridge University Press 59/3(1988-05), 457-465 0007-1145 59:3<457 1988 59 BJN CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge