Published online by Cambridge University Press: 06 August 2007
1. Results are presented of three experiments involving 112 individually fed pigs, covering the growing period between 20 and 90 kg live weight, in which the potential performance-stimulating properties of three different compounds were studied in relation to those of a dietary supplement of 250 mg Cu/kg diet.
2. The three compounds studied and the levels of supplementation used (mg/kg diet) were: Expt I arsanilic acid (100), Expt 2 sodium salicylate (200), Expt 3 a mixture of bromide salts (200); each was added to the diets either alone or with 250mg Cu/kg diet given as CuSO4, 5H2O.
3. The diets were given wet, ‘to appetite’ twice daily up to a daily maximum of 3 kg feed/pig. Measurements of length and of back-fat thickness at a number of points were made on all carcasses at slaughter.
4. Arsanilic acid and sodium salicylate alone gave growth responses similar to those obtained with Cu alone, whereas the bromide salt had no effect on performance. None of the three compounds when added to diets in conjunction with 250mg Cu/kg diet gave results superior to those obtained with the Cu supplement alone.
5. When added to the diets alone, none of the three compounds tested nor Cu had any marked effect on any of the carcass measurements.
6. Arsanilic acid reduced total liver weight and markedly reduced the large increase in total liver Cu stores that resulted from supplementation of the diets with 250 mg Cu/kg diet.