TREATMENT OF ADULT RAT WITH RECOMBINANT BOVINE SOMATOTROPIN INCREASES GROWTH DURING HEAT CHALLENGE

Authors: SPIERS, D - UNIVERSITY OF MISSOURI; EICHEN, P - UNIVERSITY OF MISSOURI; ROBINSON, E - UNIVERSITY OF MISSOURI; Matteri, Robert; BYATT, J - MONSANTO AGRIC. CO.

Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: 4/14/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Adult female rats were tested to determine growth response to recombinant bovine somatotropin (rBST) under thermoneutral (TN; 21 deg C) and heat- challenge (HC; 31 deg C) conditions. Injections were for 10 days with either rBST (20 mg/day/kg body weight) or sterile water. Body mass and feed consumption were measured at the same time. Resting metabolic rate and body temperatures were determined on the last injection day, followed one day later by determinations of fat free mass (FFM), total body water (TBW), and mass of selected organs. Feed intake relative to body mass was 34% lower for HC compared to TN rats, with no effect of treatment at either ambient temperature. Average daily gain of rBST rats was 4.5 g/day, and 94 and 591% above control level for TN and HC groups, respectively. Both FFM and TBW increased with rBST treatment (p<0.01), with no increase in mass of selected organs relative to body mass. Resting metabolic rate decreased (p<0.05) and rectal temperature increased (p<0.05) from 21 to 31 deg C wit no effect of rBST. Treatment of adult rats with rBST increases growth rate above thermoneutral control level during heat challenge, with indication of increased energetic efficiency.