Experimental Lathyrism in the White Rat. ∗

Abstract

Lathyrism, associated with the consumption of considerable amounts of certain species of legumes of the genus Lathyrus, has been a common disease of man in India, northern Africa, and occasionally in other countries. 1 Lathyrism has also been observed to occur in domestic animals and has been produced experimentally in laboratory animals. The outstanding symptoms are muscular weakness and paralysis of the extremities.

Neither Zagami, 2 McCarrison, 3 nor Visco 4 was able to produce experimental lathyrism (Lathyrus sativus, L., and Lathyrus cicera) in white rats, although impaired growth and failure of normal organ development, particularly of the reproductive and skeletal systems, were observed. Geiger and coworkers 5 produced lathyrism in rats by feeding diets which contained Lathyrus odoratus, the flowering sweet pea, at levels of 80, 50, and 25% of the diet. Characteristic symptoms were lameness, paralysis, and curvature of the spine and sternum.

Our experiments were carried out with finely ground meal (20 mesh sieve) prepared from decorticated sweet peas (Lathyrus odoratus) and as a control, with similar meal from the edible split pea of commerce† (Pisum sativum, subspecies arvense). These were incorporated into the diets of young white rats as follows: pea meal, 50%; casein (Labco, vitamin-free), 10%; corn starch, 27%; sucrose, 5%; salt mixture (modified Osborne-Mendel), 4%; cod liver oil, 2%; corn oil, 2%. Each rat received approximately 200 mg of a dried yeast tablet (Mead Johnson and Co.) daily. The casein was added to the diet to insure a satisfactory protein content, since the proteins of many legumes are known to be inadequate if fed as the sole source of protein. The total protein of the mixed diet was calculated to be 26% (16% derived from the peas).