Effect of vitamin B₁₂-deficiency on testicular tissue in rats fed by pair-feeding

The effect of vitamin B₁₂ (B₁₂)-deficiency on testicular tissue was investigated through morphological observations of the rats which had been fed on a B₁₂-deficient soybean protein diet by pair-feeding for 100 days. Testicular B₁₂ content was depressed distinctly by the deficiency. Testes weight and their relative weight (weight per 100 g body weight) as well decreased significantly as compared with those of pair-feeding control rats. Although the decrease in the testicular B₁₂ content due to B₁₂-deficiency was compensated by the administration of cyanocobalamin (CN-B₁₂), alleviation of the decrease in testes weight and relative testes weight was not observed under the condition of the short-term CN-B₁₂ administration. Morphological observations of the testicular tissue in B₁₂-deficient rats revealed atrophy of the seminiferous tubules and aplasia of sperms and spermatids, while testicular findings in both ad libitum-feeding control rats and pair-feeding control rats were normal. There was a tendency for the decrease in seminiferous tubules showing spermatogenesis to be alleviated by administration of CN-B₁₂. The above results indicate that the morphological changes in the testicular tissue are ascribable to B₁₂-deficiency.