All you IGF-1 LR3 users may be interested in the following study. This is the first study I've ever seen on the relationship between growth & IGF-1 LR3.
IGF-I and analogues can increase growth in artificially-reared neonatal pigs
F. R. Dunshea*, C. S. Chung, P. C. Owens, F. J. Ballard, and P. E. Walton
Agriculture Victoria, Victorian Institute of Animal Science, Werribee, Australia,
Department of Animal Science, Chungbuk National University, Republic of Korea,
Cooperative Research Centre for Tissue Growth and
Repair, Adelaide, Australia
Exogenous insulin like growth factor-I (IGF-I) has been shown to increase growth rate in neonatal pigs while an analogue of IGF-I, LR3IGF- I, has been shown to be more potent than IGF-I in the rat. Therefore a study was conducted to determine whether IGF-I and LR3IGF-I increase growth in the artificially reared neonatal pig.
Eighteen pigs (2 kg initial weight) pigs were infused with control, IGF-I (8 µg/h) or LR3IGF-I (8 µg/h) via osmotic pumps. After 9 days an additional pump was inserted to increase the infusion rates of each of the growth factors (16 µ/h) for a further 9 days, after which time the pigs were slaughtered. Pigs were offered bovine milk ad libitum.
Neither IGF-I nor LR3IGF-I had any effect upon daily gain over the first 9 days of the study. However, over the second 9 days of the study, daily gain was increased in LR3IGF-I infused pigs (386 v. 457 g/d, P<0.01), and tended to be increased in pigs infused with IGF-I (386 v. 413 g/d, P=0.15). As a result pigs infused with LR3IGF-I were heavier than the control pigs at slaughter. Milk intake was not different during the first 9 days of the study but was significantly greater in pigs infused with growth factors over the second half of the study (2905 v. 3407 g/d, P<0.01). Pigs treated with LR3IGF-I had a larger spleen (18.9 v. 27.5 g, P<0.001) and tended to have a larger liver (286 v. 319g, P=0.078), small intestine (329 v. 383 g, P=0.10) and combined small intestine and liver (614 v. 701 g, P=0.062) weight. Plasma IGFBP3 concentrations were highly corre- lated (R=0.85) with average daily gain over the 3 days preceding blood sampling.
In conclusion, exogenous IGF-I and particularly LR3IGF-I can increase growth rate and visceral development in ad libitum fed artificially-reared pigs. At least part of the cause was an increase in milk consumption of infused piglets