Transplantation of testicular cells, also known as spermatogonial stem cell transplantation, is a relatively new approach in the field of male infertility. We used this technique to determine whether donor-derived sperm production in unrelated porcine recipients is possible following ultrasound-guided transfer of testicular cells. This study was undertaken because we had a strain of Finnish Yorkshire boars with a hereditary recessive gene defect rendering all spermatozoa immotile and anatomically abnormal in homozygous boars. Thus, monitoring of the focal success of colonization of donor spermatogonia with subsequent production of progressively motile spermatozoa was extremely sensitive. Testicular cells from young normal crossbred boars were transplanted into the testes of two boars affected with the immotile short-tail sperm (ISTS) defect. Prior to the transplantations, busulfan was used to suppress recipients' endogenous spermatogenesis. The ejaculates were collected and analysed for the presence of motile spermatozoa. In one of the two recipient boars transplanted with testicular cells from normal donors, motile spermatozoa appeared in the ejaculates 12 weeks after the transplantation. Spermatozoa manually selected under a microscope from a frozen aliquot of ejaculate collected 27 weeks after transplantation were genotyped. In two of the 20 vials the donor-derived genotype was visible. The genotyping results substantiated the success - as indicated by the appearance of motile spermatozoa after the spermatogonial transfer. Thus, donor-derived sperm production in unrelated recipients is possible. In addition, the production after transplantation of progressively motile spermatozoa with normal tail lengths shows that the ISTS defect in Finnish Yorkshire boars apparently results from defective transcription of an essential gene for sperm motility in germline cells. To conclude, the transplantation of donor testicular cells can, at least in boars with the ISTS defect, result in complete focal spermatogenesis.

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.

An AI Ayrshire bull was subjected to cytogenetic examination due to lowered fertility. Preliminary Giemsa staining revealed a normal chromosome complement (60,XY) and G-banding did not allow us to draw a clear conclusion concerning an occurrence of chromosome rearrangement. Testicles were collected at slaughter and synaptonemal complex (SC) analysis revealed a large cross-shaped tetravalent configuration in pachytene spreads. No association between the tetravalent and XY bivalent was observed. Chromosome painting, with the use of bovine whole chromosome painting probes, conjugated with DAPI staining, facilitated a detailed description of the translocation rcp(2;4)(q45;q34). This study shows that post mortem analysis of synaptonemal complexes is a simple and useful tool for the preliminary detection of reciprocal translocation carriers.

Spermatozoa from 2 dairy AI (artificial insemination) bulls (A and B), identified by their abnormal spermiogram with cells depicting frequent macrocephaly, double tails and nuclear vacuoles, were case-investigated and compared to normal spermatozoa from a control AI sire (C). Head sizes were measured and morphological abnormalities scored using brightfield and differential interference contrast microscopy. The degree of sperm maturation and of resistance to acid-induced DNA denaturation in situ were determined after uploading of acridine orange using flow cytometry of 5,000 cells/sample. Nuclear fragmentation, i.e. the ratio of red to total (red + green) fluorescence, reached 7.1% and 31% in bulls A and B, compared to 2% in bull C. The proportion of immature spermatozoa, i.e. those with incomplete histone-protamine exchange and depicting higher green fluorescence compared to the main population of the control bull, reached 9.54% in A and 7.75% in B, compared to only 0.47% in the control. In the second part of this study the previously unknown chromosomal constitution of large-headed spermatozoa of bull A was investigated by fluorescence in situ hybridization using an X-Y painting probe set. The 7.5% XY-bearing cells and the presence of diploid spermatozoa detected by flow cytometry indicate a meiotic arrest in the first division in bull A, becoming the first proven case of association of macrocephaly and M1 diploidy. The diverse approaches used for the investigation of spermatozoal DNA provide insights into the etiology of macrocephaly.

The development and use of modern techniques, such as intracytoplasmic sperm injection (ICSI), gene knockout and sperm fluorescence in situ hybridization with chromosome- specific probes, have significantly increased our knowledge about sperm defects. We describe a new oligoasthenoteratozoospermic defect in a bull. Because of its morphological characteristics the defect was named the multinuclear-multiflagellar sperm defect. All spermatozoa in the ejaculate were abnormal. Many of the spermatozoa had multiple nuclei and multiple sperm tails. All spermatozoa lacked an acrosome, and only seldom did spermatozoa have a mitochondrial helix in the midpiece area. Meiosis and spermiogenesis were severely affected in this otherwise phenotypically normal bull. The sperm defects resembled the phenotype of a targeted gene knockout Hrb(-/-) (HIV-1 Rev-binding/interacting protein) mutant mouse strain, which is expressed as sterility in males, while females remain fertile. Since the father of this bull has been extensively used in at least three countries the defective gene has possibly become widespread in the red and white breeds (Ayrshire, Swedish Red and White, Norwegian Red) in the Nordic countries. However, it is not proved that the father of this bull is a carrier of this defect.