Current recommended levels of dietary lysine in finisher pig diets are sufficient to maximise the response to ractopamine over 28 days but are insufficient in the first 7 days

Rikard-Bell, C. V., Pluske, J. R., van Barneveld, R. J., Mullan, B. P., Edwards, A. C., Gannon, N. J., Henman, D. J. and Dunshea, F. R. (2013) Current recommended levels of dietary lysine in finisher pig diets are sufficient to maximise the response to ractopamine over 28 days but are insufficient in the first 7 days. Animal Production Science, 53 1: 38-45. doi:10.1071/AN11348


Author Rikard-Bell, C. V.
Pluske, J. R.
van Barneveld, R. J.
Mullan, B. P.
Edwards, A. C.
Gannon, N. J.
Henman, D. J.
Dunshea, F. R.
Title Current recommended levels of dietary lysine in finisher pig diets are sufficient to maximise the response to ractopamine over 28 days but are insufficient in the first 7 days
Journal name Animal Production Science   Check publisher's open access policy
ISSN 1836-0939
1836-5787
Publication date 2013-01
Year available 2012
Sub-type Article (original research)
DOI 10.1071/AN11348
Volume 53
Issue 1
Start page 38
End page 45
Total pages 8
Place of publication Collingwood, VIC., Australia
Publisher C S I R O Publishing
Collection year 2013
Language eng
Formatted abstract
Dietary ractopamine increases lean tissue deposition and responses increase as dose is increased provided sufficient dietary lysine is supplied. In Australia, diets supplemented with ractopamine (RAC) are formulated with 0.56 g available lysine per MJ digestible energy. The present study was conducted to investigate the interactions between dietary RAC and lysine on growth and carcass characteristics in ad libitum fed (13.8 MJ/kg) boars and gilts. The study involved 108 individually penned pigs at 17 weeks of age (64.1±0.57 kg) in a 2 by 2 by 3 factorial design, with the respective factors being sex (gilt or boar), dietary lysine (low and high, i.e. 0.56 or 0.65 g available lysine/MJ digestible energy, respectively) and dietary RAC (0, 5 or 20 mg/kg) for 28 days. Over the 28-day study duration, both lysine diets containing dietary RAC were sufficient to elicit a response in average daily gain (ADG) (+5.8%, P = 0.026) and carcass weight (3%, P = 0.045), but not in feed efficiency (FE) (P = 0.555). However, over the period of the first 7 days, there were interactions between the effects of RACand lysine forFE(P=0.025) andADG(P=0.023), with both traits being responsive only to dietaryRACcontaining the high lysine, which increased FE (+9.1%, P = 0.002) and ADG (+7.2%, P = 0.068). Dietary RAC improved FE in the latter stages of the study, namely Days 15-21 (+5.7%, P = 0.031) and Days 22-28 (+4.9%, P = 0.040). The highRACdiet reduced carcass P2 backfat (-16.5%,P< 0.001) and fat tissue deposition (6.2%,P=0.074) and high lysine tended to reduce fat tissue deposition (13.3%, P = 0.072). A sex by lysine interaction (P = 0.043) was observed for lean tissue deposition at 28 days, such that only the high-lysine diet increased lean deposition in boars (+11%, P < 0.05) but not in gilts. DietaryRACtended to increase lean deposition (+14.0%, P = 0.067) in the first 14 days; however, only the high RAC diet increased lean deposition (+9.6%, P < 0.05) over 28 days. In conclusion, the current recommended supplementation levels of lysine for commercial gilts and boars fed RAC may limit the response to dietary RAC if the feeding regime is for short durations and boars will not maximise their lean tissue deposition rates.
Keyword Growth performance
Carcass characteristics
Lipid deposition
Meat quality
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online 15 November 2012

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Agriculture and Food Sciences
Official 2013 Collection
 
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