THE EFFECT OF SODIUM THIOSULFATE AND HYDROXO-COBALAMIN ON RATS FED NITRILE-RICH OR GOITRIN-RICH RAPESEED MEALS

Abstract

Three experiments were conducted with rats to study the effect of feeding rapeseed preparations supplemented with sodium thiosulfate (Na2S2O3∙5H2O) and hydroxo-cobalamin (vitamin B12a). A significant antidotal effect of 0.1% sodium thiosulfate supplementation was observed with pre-hydrolyzed, freeze-dried (PHFD) raw Midas meal which is rich in nitrile content, but not with Midas meal that was not hydrolyzed. The antidotal effect of sodium thiosulfate was less conspicuous with Tower meal, but addition of 0.1% sodium thiosulfate to PHFD raw Tower meal resulted in slightly improved performance. Addition of sodium thiosulfate to heated Midas or heated Tower meal had no effect on weight gain whether they were pre-hydrolyzed or not. No antidotal effect of hydroxo-cobalamin was observed with meals of high-nitrile or high-goitrin content. The addition of sodium thiosulfate or hydroxo-cobalamin had no significant effect on the weight of thyroid glands. Increased kidney weight was observed in treatments in which meal of high nitrile content (raw Midas meals) was fed. The addition of hydroxo-cobalamin resulted in an increase in kidney weight in some treatments while the addition of sodium thiosulfate caused a decrease in kidney and liver weight in the high-nitrile treatments. A significantly higher thiocyanate content was observed in the serum of rats fed high-nitrile meals supplemented with sodium thiosulfate. Thiocyanate excretion in the urine was reduced when Midas meals were pre-hydrolyzed and freeze-dried, but remained much higher than for the control group.