The effect of Norbolethone, an anabolic steroid, on the performance and body composition of castrate pigs

Abstract

1. An experiment was carried out with 24 individually fed castrated male, Large White pigs, to examine the effects upon growth and body composition of an anabolic steroid included in finishing diets of two protein levels.2. There was a significant interaction between steroid and dietary protein level on the growth rate and food conversion efficiency. On the low protein diet growth rate and efficiency were improved by steroid treatment while with high protein intake the steroid significantly depressed growth. Analysis of the main effects showed no significant differences between steroid and protein means for food conversion efficiency and no significant difference between protein means for growth. There was a significant difference (P<0·05) for rate of growth in favour of the animals not receiving the steroid.3. Steroid significantly improved the percentage of lean and the eye muscle area, but decreased the length of pigs. High protein feeding also improved the percentage of lean and the eye muscle area and also increased the length.4. The results are discussed in relation to the use of steroids in other species, optimum time of application and the problem of ascertaining accurate physiological doses.