RAPESEED OIL MEAL AS A PROTEIN SUPPLEMENT FOR SWINE AND RATS: I. RATE OF GAIN, EFFICIENCY OF FOOD UTILIZATION, CARCASS CHARACTERISTICS AND THYROID ACTIVITY

Diets containing 0, 2 or 10 per cent expeller extracted Argentine type rapeseed oil meal were fed to swine from 3 weeks of age to market weight averaging 195 lb., and to albino rats from 3 weeks to 6 months of age. The 10 per cent level of the meal depressed the rate of liveweight gain and in some cases reduced efficiency of food utilization in both species. Food consumption was not adversely influenced by the levels of meal used in these diets. Total weight, histological sectioning and I 131 turnover rate of the thyroid gland indicated hypertrophy and other abnormalities of the gland in the animals fed 10 per cent meal. The 2 per cent level of meal did not exert consistent effects on the criteria measured. Female rats were more susceptible than males to the effects of the meal on rate of gain, but ovariectomy of females appeared to reduce this susceptibility. The nutritional quality of the diet fed to rats tended to alter the response to toxicity of the meal. Swine carcass characteristics were not markedly affected by rapeseed oil meal in the ration.