Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/16/2005
Publication Date: 6/22/2005
Citation: London, C.J., Aber, G., Sadler, M., Marchant Forde, J.N. 2005. Effects of a new growth promoter (r-albuterol) for commercial swine production. BIO 2005. Annual International Convention of Biotechnology Industry Organization. http://www.bio/org/events/2005/poster/posteronline/abs_desc.asp?p=yes&id=67. Interpretive Summary:
Technical Abstract: Several beta agonists have been tried as potential growth promoters for swine with variable success; only one is currently commercially available in the USA, ractopamine hydrochloride (Paylean®, Elanco). Ractopamine is a preferential beta-1 agonist and has been associated with both behavioral and cardiac side effects in pigs (Marchant-Forde et al., J. Anim. Sci. 2003, 81: 416 – 422.) The present study examined the physiological and behavioral effects of a new beta-2 agonist growth promoter - the enantiomerically pure version of albuterol, called R-albuterol sulfate (ST810). The ability of ST810 to deliver production effects and the behavioral effects of ST810 has now been studied in 192 finishing pigs. Pigs (89 +/- 1 kg BW) consisting of 96 barrows and 96 gilts, were housed in groups of six across 32 pens. The animals were assigned to one of four treatments: Control – no treatment; diet with 2 ppm of ST810; diet with 4 ppm of ST810 or diet with 8 ppm of racemic R, S- albuterol. All diets supplied 18.3% crude protein, 1.1% lysine and 3534 kcal ME/kg and were offered ad libitum for 4 weeks. Individual weight and pen feed intakes were recorded weekly. Behavioral assessments were monitored before and during the treatment phase and heart rates were assessed during transportation to the slaughterhouse. At slaughter, carcasses were assessed for a number of endpoints that reflected the relative carcass qualities, in particular the extent of repartitioning from fat to muscle. As little as 2 ppm ST810 had a positive effect on pig growth and carcass composition. Animals treated with ST810 were 5-6 kg heavier (P< 0.001), had more muscle weight (P< 0.01) and less fat (P< 0.05) than the control pigs. The results also demonstrate that pigs treated with ST810 do not show any of the severe behavioral side effects or any of the adverse heart rate responses previously reported for the ractopamine-treated pigs (Marchant-Forde et al., 2003). Thus, treatment with ST810 had no effect on overall handling measures (P>0.05) and no effect on behavioral responses to human presence (P>0.05). During the separate phases of transport, heart rates were not increased by ST810 (P>0.05). Biochemical data indicated that ST810 improved metabolism, without altering catecholamine levels. These studies indicate that the selective beta-2 agonist ST810 delivers positive production effects in pigs without the behavioral and cardiac side effects, previously described for ractopamine.