title: Effects over time of feeding a beta-adrenergic agonist to wether lambs on animal performance, muscle growth, endogenous muscle proteinase activities, and meat tenderness.
abstract: Forty wether lambs were used in a 2 x 4 factorial arrangement to determine the response of animal performance, muscle growth, proteinase activity, and meat tenderness to beta-adrenergic agonist (BAA) supplementation. Lambs were fed a finishing diet with or without 4 ppm of L644,969 and slaughtered after 0, 2, 4, and 6 wk of treatment. The ADG was higher (P < .05) in the treated than in the control lambs after 2 wk and returned to control levels thereafter. Semitendinosus weight and calpastatin activity were higher and mu-calpain activity was lower in the treated than in the control lambs after 2, 4, and 6 wk. Cathepsin B activity was higher (P < .01) and cystatin-like activity was lower (P < .05) after 2 wk in treated than in control lambs but returned to control levels thereafter. Longissimus protein:DNA was higher after 4 (P < .05) and 6 (P < .01) wk in the treated lambs than in the controls. The concentration of RNA and RNA:DNA ratio were higher (P < .01) in the longissimus and semitendinosus muscles in the treated lambs after 2 wk and remained higher throughout the study. Semitendinosus protein and RNA content were higher after 2, 4, and 6 wk and DNA content was higher after 2 and 6 wk in the treated than in the control lambs. Longissimus shear-force values were higher (P < .001) in the treated than in the control lambs at all slaughter end points. These data indicate a rapid alteration of muscle growth, activity of the calpain-calpastatin system, and meat tenderness during BAA treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Animal Science, University of Nebraska-Lincoln 68583-0908.
authors.forename: T D
authors.initials: TD
authors.lastname: Pringle
authors.forename: C R
authors.initials: CR
authors.lastname: Calkins
authors.forename: M
authors.initials: M
authors.lastname: Koohmaraie
authors.forename: S J
authors.initials: SJ
authors.lastname: Jones
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000375:Aging / Q000502:physiology; D000821:Animal Feed; D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002154:Calpain / Q000037:antagonists & inhibitors / Q000378:metabolism; D002403:Cathepsins / Q000378:metabolism; D015891:Cystatins / Q000378:metabolism; D004247:DNA / Q000032:analysis; D010450:Endopeptidases / Q000378:metabolism; D008297:Male; D008460:Meat / Q000592:standards*; D024510:Muscle Development; D009124:Muscle Proteins / Q000032:analysis; D009132:Muscles / Q000737:chemistry / Q000187:drug effects* / Q000201:enzymology; D011725:Pyridines / Q000494:pharmacology*; D012313:RNA / Q000032:analysis; D011897:Random Allocation; D012756:Sheep / Q000254:growth & development* / Q000378:metabolism; D015430:Weight Gain / Q000187:drug effects
chemical_list: D000318:Adrenergic beta-Agonists; D002135:Calcium-Binding Proteins; D015891:Cystatins; D009124:Muscle Proteins; D011725:Pyridines; C061557:6-amino-alpha-(((1-methyl-3-phenylpropyl)amino)methyl)-3-pyridine methanol; D012313:RNA; C033668:calpastatin; D004247:DNA; D002403:Cathepsins; D010450:Endopeptidases; D002154:Calpain