Dietary induction of mulberry heart disease and hepatosis dietetica in pigs. I. Nutritional aspects

Two trials were conducted, involving 48 Yorkshire specific pathogen-free pigs, three to four weeks old, to investigate diets which would result in a high incidence of deaths from mulberry heart disease and hepatosis dietetica in pigs. Diets based on ground corn with torula yeast resulted in a high incidence of death. Protein supplements of dried skim milk or soybean meal with corn did not induce a high incidence of death. Diets supplemented with torula yeast had the lowest selenium concentration and highest (alpha-)tocopherol concentration of the diets investigated and resulted in lower liver selenium concentrations. A higher frequency of hepatosis dietetica, mulberry heart disease, skeletal muscle degeneration and exudative diathesis was observed in pigs fed the low level selenium diets containing torula yeast.

Ultrastructural changes in muscular dystrophy. I. Cardiac tissue of piglets deprived of vitamin E and selenium

The ultrastructure of cardiac tissue from neonate, 3-, 6-, 8-, and 12-week-old piglets, born of vitamin E- and selenium-deprived sows was studied. A progression of lesions occurred in nonmuscular components of this tissue; the first lesion appeared in connective tissue elements. Fibroblasts and the extracellular compartment appeared most severely altered in the neonate, and progressive vascular damage was very evident from 3 to 12 weeks of age. Similarly, neuronal elements appear altered at 3 weeks and were almost nonevident in areas showing marked lesions at 8 and 12 weeks. Fairly extensive alterations were evident in all of these elements before any marked changes become evident in the muscle. The relevance of these observations is discussed in relation to the etiology of the disease.

Ultrastructure of muscular dystrophy. II. A comparative study in lambs and chickens

The ultrastructure of the semitendonosus muscle of lambs and the pectoralis major muscles of chickens suffering from nutritional muscular dystrophy were studied. Samples of tissue from histologically normal and mildly degenerate areas were examined. Ultrastructural examination of areas that appeared apparently normal histologically, revealed lesions in the small vessels, connective tissue elements and neuromuscular elements. The possible relationship of these findings to the etiology of this disease are discussed.

Difficulties in the management of Sminthopsis crassicaudata due to iodine deficiency and thyroid disease

Sminthopsis crassicaudata, imported from a laboratory colony in Australia, originally bred successfully in this country, but 4 months after importation animals began to die with enlarged thyroid glands which were devoid of colloid. Deaths were not prevented until the iodine intake was increased to 60 μg/day. It is possible that this high iodine requirement is in some way related to the mineral content of the soils from whence the animals which formed the nucleus of the Australian colony were obtained.

Spontaneous tumours occur in the species; we observed several animals with uterine polyps and one with a reticulum-cell sarcoma. An X-irradiated animal developed a thyroid carcinoma.