Infertile Boars with Knobbed and Immotile Short‐tail Sperm Defects in the Finnish Yorkshire Breed

Abstract

In the period 1996-2006 two specific sperm defects, the knobbed acrosome (KA) defect and the immotile short-tail sperm (ISTS) defect, showed a strong negative association with fertility in Finnish breeding boars. In this study, we examined the incidence of these two sperm defects in two pig breeds, their effects on fertility and their associations with sperm morphology and testicular histology. Semen samples from 2048 (1097 Yorkshire, 951 Landrace) boars were collected. None of the Landrace boars revealed either the KA defect or the ISTS defect. Of the Yorkshire boars, 0.8% were afflicted with the KA defect and 7.6% with the ISTS defect. Boars diagnosed with the ISTS defect produced no litters. Fertility data were available from two artificially inseminated (AI) boars and six farm breeding boars affected with the KA defect. Breeding boars with 45-81% knobbed spermatozoa (n = 6) did not produce any litters out of 71 sows bred. AI boars with 25-30% knobbed spermatozoa had a poor non-return rate (on average 47% compared with 85% for normal control boars) and produced small litters, on average 2.5 piglets less than other boars of the same breed. Morphometry of testicular tissue and distribution of different cells in the seminiferous tubules were examined in nine boars. Boars with the KA defect had a smaller diameter of the seminiferous tubules (p < 0.05) and a lower number of Sertoli cells (p < 0.05) than controls. ISTS boars, in turn, had a significantly lower number of elongated spermatids (p < 0.05), and they also produced on average only 12% of the spermatozoa of normal boars. The ISTS defect is a manifestation of an autosomal recessive disease caused by an insertion in the KPL2 gene in porcine chromosome 16. Although we tried to map the KA defect, its aetiology remains unclear.

Semen effects on insemination outcomes in sows

“…In the current study, abnormal acrosomes were not associated with either litter size or pigs born alive. This differs from the findings of Kopp et al (2008) in which abnormal acrosomes were implicated in reduced litter size. In the present study, the knobbed acrosome defect was rarely detected in the semen samples which is consistent with findings from the previous studies where this abnormal morphology was observed in less than 1% of sperm of Yorkshire boars (Kopp et al, 2008).…”

In vivo Genotoxicity Studies of Cefotaxime

“…A positive correlation was previously reported between tail abnormalities and infertility (Kopp et al 2008). In conclusion, our results reveal the potential toxic effect of cefotaxime on the genetic material.…”

Knobbed acrosome defect is associated with a region containing the genes STK17b and HECW2 on porcine chromosome 15

“…Knobbed acrosome defect has been recently described in the Finnish Yorkshire pig population [15]. Testicular weights of boars with KAD did not differ from control boars.…”

“…globozoospermia in humans, where spermatozoa lack an acrosome [7-9] and the knobbed acrosome defect (KAD) in bulls, boars, stallions, rams, and dogs [10-15]. The acrosome is an organelle that develops over the anterior half of the head in the spermatozoa.…”

“…Testicular weights of boars with KAD did not differ from control boars. However, affected boars had a smaller seminiferous tubule diameter and lower number of Sertoli cells relative to control boars [15]. Investigation of the pedigrees of KA-affected boars suggested an autosomal recessive inheritance of the defect.…”