|Yen, Jong Tseng|
Submitted to: Feedinfo News Service
Publication Type: Popular Publication
Publication Acceptance Date: 3/13/2006
Publication Date: 3/18/2006
Citation: Klindt, J.M., Kerr, B.J., Buonomo, F.C., Yen, J. 2006. Lysine requirement of finishing pigs treated with porcine somatotropin by sustained-release implants. Feedinfo News Service. Available: http://www.feedinfo.com/console/PageViewer.aspx?page=396533&str=KLINDT. Interpretive Summary:
Technical Abstract: To alleviate laborious daily injection of porcine somatotropin (pST), a sustained-release implant (pST-SR) has been developed to deliver continuously a daily dose of 2 mg of pST to pigs for 42 d. In the present study, 96 white composite (Large White x Landrace) finishing barrows (83.6 +/- 1.2 kg BW) were assigned to receive 0 or 2 pST-SR implants (4 mg pST/d) and to consume one of six diets differing in total lysine concentration (0.29, 0.52, 0.75, 0.98, 1.21, and 1.44). Diets were formulated to be isocaloric and based on ideal protein concept. Pigs were housed individually, allowed ad libitum access to feed and water, and slaughtered at 112 kg BW. The pST-SR affected neither ADG (P = 0.88), nor 10th rib longissimus muscle area (LMA, P = 0.51), but decreased (P < 0.01) ADFI, average backfat thickness, 10th rib fat depth, leaf fat, and ham fat, improved (P < 0.05) gain/feed (G/F), and increased (P < 0.01) weights of four trimmed lean cuts (T-cuts), and ham lean and bone percentages. Increasing total lysine increased ADG (linear, P < 0.01; quadratic, P < 0.05) and ADFI (linear, P < 0.01). The G/F, plasma urea N (PUN) and T-cuts were affected by pST-SR x dietary lysine interactions (P <0.01). Without pST-SR, the G/F of was not different (P = 0.37) between pigs fed 0.52% and higher total lysine. With pST-SR, the G/F was lower (P < 0.05) for pigs fed 0.52% than 0.98 and 1.44% total lysine. Without pST-SR, increasing total lysine increased PUN linearly (P <0.01). With pST-SR, no PUN differences (P = 0.19) occurred between 0.29 and 0.52%, 0.98 and 1.21%, or 1.21 and 1.44% total lysine feedings. The T-cuts of pigs without pST-SR were not different (P = 0.30) among those fed 0.29, 1.21, and 1.44% total lysine. With pST-SR, the T-cuts were lower (P < 0.01) for those fed 0.29% than 1.21 and 1.44% total lysine. Estimates of total lysine requirements of pigs without and with pST-SR, respectively, were 0.52 and 0.86% for growth (ADG and G/F) and 0.173 and 0.88% for lean production (LMA and T-cuts). Equivalent apparent ileal digestible lysine requirements of pigs without and with pST-SR, respectively, were 0.44 and 0.68% for growth, and 0.62 and 0.75% for lean production. A daily intake approximately 26.1 g of total lysine or 22.4 g of apparent ileal digestible lysine is needed to maximize lean production in finishing barrows receiving 4 mg pST/d via sustained-release implant.