Multinuclear-multiflagellar sperm defect in a bull--a new sterilizing sperm defect

Area of Science:

• Veterinary Science
• Reproductive Biology
• Genetics

Background:

• Modern reproductive techniques like intracytoplasmic sperm injection (ICSI) and gene knockout models have advanced the study of sperm defects.
• Understanding male infertility is crucial for animal breeding and conservation.

Observation:

• A new oligoasthenoteratozoospermic defect was observed in a bull, characterized by multinuclear and multiflagellar spermatozoa.
• All observed spermatozoa lacked acrosomes, and few possessed a mitochondrial helix, indicating severe defects in meiosis and spermiogenesis.

Findings:

• The bull exhibited a severe, previously undescribed sperm defect named multinuclear-multiflagellar sperm defect.
• The observed sperm abnormalities in the bull closely resemble the phenotype of the Hrb(-/-) gene knockout mouse model, suggesting a potential genetic link.

Implications:

• The genetic defect may have spread through the sire's lineage in Nordic red and white cattle breeds (Ayrshire, Swedish Red and White, Norwegian Red).
• Further investigation is needed to confirm if the sire carries the defective gene and to assess the full extent of its prevalence in cattle populations.