A mixt. of the isomers 3-tert-butyl-4-hydroxyanisole and 2-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxytoluene and 6-ethoxy-2,2,4-trimethyl-1H-quinoline were added as synergistically acting antioxidants to the susceptible to oxidn. feed for carnivorous animals (fats, oils, rendering meal). The addn. resulted in a stabilization of the feed. In particular, a decrease in the feed decompn. (decay, rancidity of fats), formation of biolog. toxins and in the development of pathogenic microorganisms was obsd.