Elevation of a Specific mRNA in Longissimus Muscle of Steers Fed Ractopamine

Smith, Stephen B.; Garcia, Denise K.; Anderson, D. B.

doi:10.2527/jas1989.67123495x

Cited by 52 publications

(26 citation statements)

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“…One unique aspect of our experiment is the investigation of gene expression at two time points relative to the administration of clenbuterol. Previous studies have focused on altered gene and/or protein expression after significant changes in muscle mass have occurred [12,13,23]. However, results of our study indicate that changes in gene expression are equally abundant at an early time point relative to the initiation of clenbuterol administration.…”

Section: Discussioncontrasting

confidence: 70%

Changes in skeletal muscle gene expression following clenbuterol administration

2006

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Background: Beta-adrenergic receptor agonists (BA) induce skeletal muscle hypertrophy, yet specific mechanisms that lead to this effect are not well understood. The objective of this research was to identify novel genes and physiological pathways that potentially facilitate BA induced skeletal muscle growth. The Affymetrix platform was utilized to identify gene expression changes in mouse skeletal muscle 24 hours and 10 days after administration of the BA clenbuterol.

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Section: Discussioncontrasting

confidence: 70%

Changes in skeletal muscle gene expression following clenbuterol administration

2006

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“…This result was comparable to data reported for trials using ractopamine from steers, when the total RNA content of 1. dorsi was not changed by treatment [37]. Other studies with rat [5], however, have suggested B-agonist-induced increases in muscle RNA, indicating the likelihood of muscle type and species variation.…”

Section: Analysis Of Bovine Rnamentioning

confidence: 77%

Changes in calpain and calpastatin mRNA induced by β‐adrenergic stimulation of bovine skeletal muscle

Parr

Bardsley

Gilmour

et al. 1992

European Journal of Biochemistry

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Administration of 8-adrenergic agonists to mammals can produce skeletal muscle hypertrophy in some species and muscle types. The growth-promoting effect appears to be due to suppression of protein breakdown rather than stimulation of synthesis, although evidence from turnover studies is equivocal. In ovine muscle, changes in thc activity of the calcium dependent neutral proteinases (calpains I and IT) and their specific inhibitor (calpastatin) accompany b-agonist-induced hypertrophy. These observations suggest that the calpain system is involved in myofibrillar protein turnover in some way. Alternatively, the relationship with hypertrophy may be indirect, since the calpains also interact with hormone and growth-factor receptors, protein kinase C and transcription factors, in addition to a range of membrane, cytoskeletal and nuclear proteins.In the present study, attempts have been made to determine if the 8-agonist-induced effects on the calpain system are associated with corresponding changes in specific mRNA. The activity of both calpain isoforms and calpastatin was measurcd in bovine lorigissirnus dorsi samples from trials in which test animals were treated with the agonist cimaterol. Total RNA was extracted from the muscle samples. A cDNA probe for calpastatin mRNA was generated from bovine RNA by the polymerase chain reaction. This cDNA and a human calpain-11 large-subunit cDNA were used to detect specific mRNA by Northern-blot analysis.8-agonist treatment of Friesian steers caused significant longissitnus dorsi hypertrophy. Increases in muscle mass (+37%, P < 0.005), calpain-I1 specific activity (+27%, P < 0.05) and calpastatinspecific activity (+ 76%, P < 0.05) were found in treated animals. Total RNA was unchanged, but there was a 96% overall increase in calpastatin mRNA and a 30% increase in calpain-I1 large-subunit mRNA in muscle from treated animals. The mRNA changes are similar in direction and degree to the activity changes. Both calpain-I1 large subunit and inhibitor expression may therefore be stimulated by agonist action at the level of transcription or mRNA stabilisation. Multiple calpastatin mRNA species were detected in steers, as reported for other species. Differential changes in these messages: induced by the p agonist, suggest thar expression or stability of alternative mRh-A species may be a factor in calpastatin regulation.

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“…This β-AA induced muscle hypertrophy is accredited to an increased rate of muscle α-actin synthesis, as well as to the inhibitory activity of calpastatin (Smith et al, 1989;Yang and McElligott, 1989). Fat deposition in several organs can also be usually affected by β-AA supplementation.…”

Section: Discussionmentioning

confidence: 99%

Effects of ractopamine hydrochloride and dietary protein content on performance, carcass traits and meat quality of Nellore bulls

Cônsolo

Mesquita

Rodríguez

et al. 2016

Animal

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Ractopamine hydrochloride (RH) alters protein metabolism and improves growth performance in Bos taurus cattle with high carcass fat. Our objective was to evaluate the effects of RH, dietary CP and RH × CP interaction on performance, blood metabolites, carcass characteristics and meat quality of young Nellore bulls. A total of 48 bulls were randomly assigned to four treatments in a 2 × 2 factorial arrangement. The factors were two levels of dietary CP (100% and 120% of metabolizable protein requirement, defined as CP100 and CP120, respectively), and two levels of RH (0 and 300 mg/animal·per day). Treated animal received RH for the final 35 days before slaughter. Animals were weighed at the beginning of the feedlot period (day 63), at the beginning of ractopamine supplementation (day 0), after 18 days of supplementation (day 18) and before slaughter (day 34). Animals were slaughtered and hot carcass weights recorded. After chilling, carcass data was collected and longissimus samples were obtained for determination of meat quality. The 9-11th rib section was removed for carcass composition analysis. Supplementation with RH increased ADG independently of dietary CP. There was a RH × CP interaction on dry matter intake (DMI), where RH reduced DMI at CP120, with no effect at CP100. Ractopamine improved feed efficiency, without RH × CP interaction. Ractopamine had no effect on plasma creatinine and urea concentration. Greater dietary CP tended to increase blood urea, and there was a RH × CP interaction for plasma total protein. Ractopamine supplementation increased plasma total protein at CP120, and had no effect at CP100. Ractopamine also decreased plasma glucose concentration at CP100, but had no effect at CP120. Ractopamine increased alkaline phosphatase activity at CP120 and had no effect at CP100. There was a tendency for RH to increase longissimus muscle area, independently of dietary CP. Ractopamine did not alter fat thickness; however, fat thickness was reduced by greater CP in the diet. Supplementation with RH decreased meat shear force, but only at day 0 of aging, having no effect after 7, 14 or 21 days. Greater dietary protein increased meat shear force after 0 and 7 days of aging, with no effect after 14 or 21 days. These results demonstrate for the first time the efficacy of ractopamine supplementation to improve gain and feed efficiency of intact Bos indicus males, with relatively low carcass fat content. Ractopamine effects were not further improved by increasing dietary protein content above requirements.

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Elevation of a Specific mRNA in Longissimus Muscle of Steers Fed Ractopamine

Cited by 52 publications

References 0 publications

Changes in skeletal muscle gene expression following clenbuterol administration

Changes in skeletal muscle gene expression following clenbuterol administration

Changes in calpain and calpastatin mRNA induced by β‐adrenergic stimulation of bovine skeletal muscle

Effects of ractopamine hydrochloride and dietary protein content on performance, carcass traits and meat quality of Nellore bulls

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