Experimental diets for the study of lipid influence on the induced mammary carcinoma in rats: II--Suitability of the diets.

ABSTRACT

We have previously reported one method for obtention of experimental diets for the study of the effects of dietary lipids on the rat breast carcinoma. The purpose of this second part of the study was to develop a quality control system for demonstrating the suitability of these diets. This system is essentially based on the animals' growth control, their period clinical examination as well as the anatomopathological postmortem study of the animals submitted to such diets. Two groups of weaning rats, control (C) and hyperlipidic (HL), were submitted to a low-fat diet (N3) or a high-fat polyunsaturated--corn oil--diet (HL20) respectively. At 53 days of age all animals were induced with 5mg of dimethylbenz (a) anthracene. Experiments were ended when animals reached a mean age of 214 days. The results show 1) a normal ponderal evolution of the animals in the two experimental groups with respect to two series of the same strain fed with a standard diet, and 2) the homogeneity of growth determined by the coefficient of variance study. On the other hand, neither the weekly clinical examination nor the anatomopathological post-mortem studies revealed any pathology that could be specifically attributed to nutritional imbalance. These results confirm the suitability of both diets for rat growth. Their use in the study of the effects of dietary lipids on the mammary carcinoma would satisfy the initial aim of guaranteeing the specificity of the results.