Ultrastructural abnormalities of boar spermatozoa.

Described here are the main ultrastructural malformations observed in spermatozoa of ejaculates collected from healthy, adult Landrace boars following 2 days of sexual abstinence. Previously semen had been collected 3 times per week. Sperm concentration in the cell-rich fraction of ejaculates was approximately 700,000 sperm/mm(3). The aberrant gamete forms did not exceed 2% of the total number of spermatozoa. Ultrastructural anomalies of spermatozoa were classified into 2 groups: head malformations and tail malformations. These consisted of: 1) spermatozoa with expanded and vacuolated acrosomes, 2) spermatozoa with myelin figures within the perinuclear space, 3) macrocephalic spermatozoa with 2 nuclei and a deformed acrosomal vesicle, 4) spermatozoa with an expanded acrosomal apex, 5) spermatozoa with nuclear vacuoles, 6) macrocephalic spermatozoa with a roundish head, 7) spermatozoa with swollen mitochondria, 8) spermatozoa with additional mitochondria over the mitochondrial sheath, 9) spermatozoa without the central microtubular pair, 10) spermatozoa without some peripheral doublets, 11) spermatozoa with 1 or 2 coiled tails, 12) spermatozoa with a folded tail and a disorganized connecting piece, 13) spermatozoa with a vesiculated tail, and 14) spermatozoa with 2 tails fused by their respective mitochondrial sheaths.