ABSTRACT:

Saccharomyces cerevisiae (S. cerevisiae) is commonly added to animal diets for its probiotic and nutritional benefits, particularly in promoting digestion and growth. However, its effects on male reproductive health are not well understood. This study evaluated how different dietary levels of S. cerevisiae affect testicular and accessory organ development in male Wistar rats. Twenty male rats were divided into four groups and supplemented with 0 (control), 0.5, 1.0, or 1.5 g/kg body weight of S. cerevisiae for 35 days. Final assessments included body weight, organ weights, and testicular morphometry. Rats receiving higher yeast doses gained significantly less weight. Absolute testicular and epididymal weights declined with increasing supplementation, while relative weights increased—likely due to reduced overall body mass. Testicular circumference, length, diameter, and volume also decreased in a dose-dependent manner. Non-reproductive organs such as the liver, kidney, and spleen showed reduced absolute weights without changes in relative values. These results indicate that excessive S. cerevisiae may impair reproductive organ development, highlighting the need for regulated supplementation. Further research is needed to understand the underlying mechanisms and potential long-term reproductive effects