| Back Topic Categories Search Previous Abstract Next Abstract |
Abstract: 89
Jeffrey Clapper1 *, Tina Clark1
Dept. of Animal & Range Science, South Dakota State University, Brookings, SD 1
To determine if changes in IGF-I and IGFBPs in the serum and anterior pituitary gland (PIT) may play a role in altering PIT LH during feed restriction, forty crossbred gilts of similar age and weight were randomly assigned to one of two groups, CON (n=20) or FR (n=20) on d 1. CON gilts were fed 3 kg of a corn-soy diet daily while FR gilts received 1 kg. Blood samples were obtained from gilts by jugular venipuncture on d 1, 7, and 14. Ten FR and 10 CON gilts were killed on d 8 and PITs were collected. The remaining FR and CON gilts were fed 3 kg of the diet daily, then killed on d 15 and PITs collected. At d 1, serum concentrations (ng/ml) of IGF-I were similar (P>.05) between FR and CON gilts. By d 7, serum concentrations of IGF-I were decreased (P<.01) in FR (66.8 ± 4.4) compared to CON gilts (108.7 ± 4.4), but were similar (P>.05) at d 14. Concentrations of IGF-I and LH in PITs were similar (P>.05) in FR and CON gilts on d 7 and 14. Ligand blot analysis detected 46 and 41 kDa forms of IGFBP-3, IGFBP-2 and 28 and 24 kDa forms of IGFBP-4 in the serum. Relative amounts of the 41 kDa form of IGFBP-3 were less (P<.01) in FR gilts (.96 ± .07) compared to CON gilts (1.35 ± .07) on d 7, but were similar (P>.05) on d 14. No difference was detected (P>.05) in relative amounts of any other serum IGFBP in FR and CON gilts. No differences were detected (P>.05) in PIT concentrations of LH or IGF-I in FR and CON gilts on d 7 or 14. Ligand blot analysis detected 33 and 29 kDa IGFBPs in the PIT. No difference was detected (P>.05) in relative amounts of either IGFBP in FR and CON gilts. In conclusion, short-term feed restriction does not appear to alter PIT concentrations of IGF-I, LH or relative amounts of IGFBPs.
This abstract is being presented on Sunday, August 1 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.