1. ¹QAF Meat Industries, Corowa, New South Wales, Australia
2. ²VGX Pharmaceuticals, The Woodlands, Texas, USA
3. ³VGX Animal Health, The Woodlands, Texas, USA

Correspondence: Ruxandra Draghia-Akli, VGX Pharmaceuticals, Inc., 2700 Research Forest Drive, Suite 180, The Woodlands, Texas 77381, USA. E-mail: rdraghia@vgxp.com

Received 18 June 2008; Accepted 17 July 2008; Published online 19 August 2008.

Abstract

LifeTideSW5 is a growth hormone–releasing hormone (GHRH)–expressing plasmid delivered by intramuscular (IM) electroporation (EP), and the first therapeutic plasmid delivered by this physical method to be approved for use in food animals. Gestating sows (n = 997) were treated once with a single 5-mg GHRH-plasmid by EP or served as controls. Data on offspring from three parities subsequent to treatment were collected. No adverse effects related to treatment were noted. First parity post-treatment offspring from treated sows displayed a 2.93 kg (P < 0.0001) increase in carcass weight (CW), 1.0 mm (P < 0.0001) less back-fat (P2), and a 27.0 g CW/day (P < 0.0001) increase in rate of gain (ROG) compared with controls. An increase of 21.6% was recorded in the number of offspring surviving. In the second and third parities post-treatment, offspring from treated females displayed higher number of born alive and total born number, and lower stillborn rates. Third parity offspring from treated sows displayed a 1.6 kg advantage in CW (P < 0.05), 1.0 mm less P2 (P < 0.05), and a 10.0 g CW/day benefit in ROG. Furthermore, offspring from treated females had a 19.04% lower post-wean loss rate. Overall, plasmid GHRH administration decreased morbidity and mortality in treated females and their offspring over three consecutive pregnancies.