A preliminary investigation of the effects of diets on lesion formation in the hindgut of adult female American cockroaches

Abstract

A preliminary investigation of the general relationships between different levels and sources of dietary nitrogen and lesion formation in the alimentary canal of adult female American cockroaches, Periplaneta americana (L.), has been conducted. Increasing levels of casein protein in the diet could not be clearly correlated with an increased incidence of lesions, but very high casein protein levels produced gross tissue abnormalities in the hindgut. Diets containing casein hydrolysate appeared to enhance lesion formation. When 1% additions of kynurenic acid, xanthurenic acid, tryptophan, and uric acid were made as supplemental sources of nitrogen, lesions appeared in a greater number of animals. Except in the case of uric acid, these spiked diets resulted in a lower total lesion area than when the nitrogen source was casein hydrolysate alone. Additions of an antibiotic, neomycin, to casein hydrolysate diets resulted in a lower level of lesion-forming activities.Lesion formation which was enhanced by dietary means appeared to result from an inflammatory reaction involving hemocytes. It is proposed that these inflammations were caused by high ammonia concentrations and irritant bacterial metabolites present in the gut lumen. No evidence was found to indicate that oxyuroid nematodes contributed to hindgut lesion formation.