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- Hoflack, G., et al.
(författare)
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Testicular dysfunction is responsible for low sperm quality in Belgian Blue bulls
- 2008
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Ingår i: Theriogenology. - : Elsevier. - 0093-691X .- 1879-3231. ; 69:3, s. 323-332
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study, we demonstrated that Belgian Blue (BB) bulls have a higher prevalence of small scrota and poorer semen morphology compared to the Holstein Friesian (HF) breed in Belgium. The present study tested the hypothesis that the underlying reason for these BB traits negative to fertility was testicular degeneration, associated with an eventual hypoplastic background. At culling, sperm quality and testicular histology of BB bulls were assessed and compared to that of HF bulls. Besides semen quality being generally poorer in the BB breed, significantly more degenerative changes were encountered in BB compared to HF testicles (degeneration index: 37.7 +/- 11.9 versus 29.3 +/- 9.9 for BB and HF bulls, respectively; P = 0.053). These results correlated to the percentage of normal spermatozoa (r = -0.44; P = 0.024) and primary abnormalities (r = 0.38; P = 0.053). Moreover, the relative amount of collagen fibers present in the testicular interstitial connective tissue was correlated with % normal sperm (r = -0.47; P = 0.017), primary defects (0.48; P = 0.014), and the degeneration results (r = 0.63; P less than 0.001). The % testicular interstitial collagen fibers differed significantly between breeds (10.6 +/- 4.0% for the BB versus 7.6 +/- 1.9% for the HF bulls; P = 0.016). This increased amount of connective tissue in BB testes might hypothetically be responsible for the poorer sperm quality. This condition can be defined as a mild form of testicular hypoplasia, and might, in turn, be responsible for the higher sensitivity to testicular degeneration, which is encountered in the BB breed. (C) 2008 Elsevier Inc. All rights reserved.
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- Thys, M., et al.
(författare)
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In vitro Fertilizing Capacity of Frozen-thawed Bull Spermatozoa Selected by Single-layer (Glycidoxypropyltrimethoxysilane) Silane-coated Silica Colloidal Centrifugation
- 2009
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Ingår i: Reproduction in domestic animals. - : Wiley-Blackwell. - 0936-6768 .- 1439-0531. ; 44:3, s. 390-394
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Tidskriftsartikel (refereegranskat)abstract
- Barriers to the use of density gradient centrifugation for preparing animal spermatozoa for artificial insemination (AI) include the scarcity of animal-specific formulations and the daunting prospect of processing large volumes of ejaculate in small aliquots (1.5 ml extended semen). Recently, new colloid formulations have been tested in vitro in a modified procedure, centrifugation on a single layer of colloid. The present study investigated the fertilizing ability during in vitro fertilization (IVF) of frozen-thawed bovine spermatozoa following centrifugation through a single layer of glycerolpropylsilane (GS)-coated silica colloid with a species-specific formulation (patent applied for; treatment, T). Controls (C) included centrifugation through gradients of either the same colloid (C1) or Percoll (TM) (C2). Sperm recovery surpassed 50% for both C1-C2 and T (n.s.). Mean values of various parameters of computerized analysis of sperm motility did not differ between T and C1 (n.s.), and only the proportions of path straightness and linearity were lower in T vs C2 (p less than 0.05). In T, the mean (+/- SD) percentages of fertilization rate, blastocyst development rate and the total number of blastomeres were 58.1 +/- 23.3%, 24.5 +/- 14.3% and 94.6 +/- 23.4%, respectively. The proportions did not differ significantly from controls (C1/C2). Therefore, centrifugation through a single layer of colloid offers an alternative method to density gradient centrifugation for selection of viable, potentially fertile frozen-thawed bull spermatozoa. This single-layer technique is gentle, versatile and convenient because it facilitates scaling-up the process of sperm preparation to allow larger numbers of spermatozoa (for instance, whole ejaculates) to be processed for AI.
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