Cationic extracts of egg yolk and their effects on motility, survival and fertilising ability of bull sperm

Vishwanath, R.; Shannon, Patrick; Curson, B.

doi:10.1016/0378-4320(92)90032-9

Cited by 35 publications

(16 citation statements)

References 15 publications

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“…It has been shown that sperm motility could be maintained more than 8 days when semen is diluted with EY-TG extender and cooled [50] and that EY is the extender constituent that is responsible for maintaining motility [25,48,51]. Furthermore, after 24 h of incubation, motility was better in semen diluted with extender containing LDF than whole EY.…”

Section: Discussionmentioning

confidence: 93%

Low-Density Lipoprotein Fraction from Hen’s Egg Yolk Decreases the Binding of the Major Proteins of Bovine Seminal Plasma to Sperm and Prevents Lipid Efflux from the Sperm Membrane1

Bergeron

Crête

Brindle

et al. 2004

Biology of Reproduction

167

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For sperm preservation, semen is generally diluted with extender containing egg yolk (EY), but the mechanisms of sperm protection by EY are unclear. The major proteins of bull seminal plasma (BSP proteins: BSP-A1/A2, BSP-A3, and BSP-30-kDa) bind to sperm surface at ejaculation and stimulate cholesterol and phospholipid efflux from the sperm membrane. Since EY low-density lipoprotein fraction (LDF) interacts specifically with BSP proteins, it is proposed that the sequestration of BSP proteins in seminal plasma by EY-LDF represents the major mechanism of sperm protection by EY. In order to gain further insight into this mechanism, we investigated the effect of seminal plasma, EY, and EY-LDF on the binding of BSP proteins to sperm and the lipid efflux from the sperm membrane. As shown by immunodetection, radioimmunoassays, and lipid analysis, when semen was incubated undiluted or diluted with control extender (without EY or EY-LDF), BSP proteins bound to sperm in a time-dependent manner, and there is a continuous cholesterol and phospholipid efflux from the sperm membrane. In contrast, when semen was diluted with extender containing EY or EY-LDF, there was 50%-80% fewer BSP proteins associated with sperm and a significant amount of lipid added to sperm membrane during incubation. In addition, sperm function analysis showed that the presence of EY or EY-LDF in the extender preserved sperm motility. These results show that LDF is the constituent of EY that prevents binding of the BSP proteins to sperm and lipid efflux from the sperm membrane and is beneficial to sperm functions during sperm preservation.

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Section: Discussionmentioning

confidence: 93%

Low-Density Lipoprotein Fraction from Hen’s Egg Yolk Decreases the Binding of the Major Proteins of Bovine Seminal Plasma to Sperm and Prevents Lipid Efflux from the Sperm Membrane1

Bergeron

Crête

Brindle

et al. 2004

Biology of Reproduction

167

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“…The effect of egg yolk on the success of sperm storage and the mechanisms involved have been studied extensively [12,[22][23][24][25]. It is suggested that the EY lipoproteins associate with sperm membranes and shield against the toxic effect of SP.…”

Section: Discussionmentioning

confidence: 99%

“…It is speculated that the LDF associates with sperm membranes and provides protection against membrane damage, but there is contradictory evidence concerning the stability of this association [12,[22][23][24]. Vishwanath et al [25] suggest that EY lipoproteins compete with detrimental seminal plasma (SP) cationic peptides (Ͻ5 kDa) in binding to the sperm membrane and thus protect the sperm.…”

Section: Introductionmentioning

confidence: 97%

Major Proteins of Bovine Seminal Plasma Bind to the Low-Density Lipoprotein Fraction of Hen's Egg Yolk1

Manjunath

Nauc

Bergeron

et al. 2002

Biology of Reproduction

173

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Over the past 60 years, egg yolk (EY) has been routinely used in both liquid semen extenders and those used to cryopreserve sperm. However, the mechanism by which EY protects sperm during liquid storage or from freezing damage is unknown. Bovine seminal plasma contains a family of proteins designated BSP-A1/-A2, BSP-A3, and BSP-30-kDa (collectively called BSP proteins). These proteins are secretory products of seminal vesicles that are acquired by sperm at ejaculation, modifying the sperm membrane by inducing cholesterol efflux. Because cholesterol efflux is time and concentration dependent, continuous exposure to seminal plasma (SP) that contains BSP proteins may be detrimental to the sperm membrane, which may adversely affect the ability of sperm to be preserved. In this article, we show that the BSP proteins bind to the low-density fraction (LDF), a lipoprotein component of the EY extender. The binding is rapid, specific, saturable, and stable even after freeze-thawing of semen. Furthermore, LDF has a very high capacity for BSP protein binding. The binding of BSP proteins to LDF may prevent their detrimental effect on sperm membrane, and this may be crucial for sperm storage. Thus, we propose that the sequestration of BSP proteins of SP by LDF may represent the major mechanism of sperm protection by EY.

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“…). In the first 3 experiments a cloudy precipitate was observed before freezing, presumably of cationic egg yolk lipoproteins (Vishwanath et al, 1991 ), in the zwitterion diluents containing 18% (v/v) egg yolk, which may have impaired cryoprotection of spermatozoa. Thus, in subsequent experiments, the egg yolk and buffer combination were centrifuged as reported for bull semen freezing diluents , prior to the addition of glycerol and glucose, and the supernatant was used in the semen diluent.…”

Section: Discussionmentioning

confidence: 99%

In vitro evaluation of zwitterion buffers in diluents for freezing ram spermatozoa

Molinia

Evans²,

Maxwell³

1994

Reprod. Nutr. Dev.

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Summary ― Diluents based on the zwitterion buffers Tes, Hepes and Pipes titrated to pH 7.0 with NaOH or Tris were compared with Tris-citrate diluents by assessment of post-thawing motility and acrosome integrity of frozen ram spermatozoa. Varying buffer osmolalities between 300 and 360 mosmol had no effect but there was a decrease (P < 0.001 ) in motility between 360 and 420 mosmol. There was a quadratic effect (P < 0.001 ) on motility of increasing glucose concentration in the diluent (30, 85, 140, 195 and 250 mM) with a maximum at 85 mM. At this sugar concentration, motility was higher (P < 0.001 ) for diluents containing glucose and fructose than lactose, sucrose or trehalose. Inclusion of egg yolk (optimum at 13.5% v/v; P < 0.05), centrifugation of the diluents (P < 0.01 use of low dilution rates (3 or 6-fold; P < 0.05) and freezing in pellets rather than minitubes or straws (P < 0.001 ) improved both the motility and acrosome integrity of spermatozoa in the zwitterion diluents. It is concluded that zwitterion buffers are superior to Tris-citrate in ram semen freezing diluents. zwitterion buffer / motility / acrosome integrity / frozen ram spermatozoa Résumé ― Effet de l'addition de tampons amphotères à des dilueurs sur la congélabilité des spermatozoïdes de bélier. Nous avons comparé l'efficacité de dilueurs à base de tampons amphotères TES, HEPES et PIPES ajustés à pH 7,0 avec NaoH ou tris, à celle de milieux à base de tris-citrate, en évaluant la motilité des spermatozoïdes de bélier et l'intégrité de leur acrosome après congélation. Entre 300 et 360 milliosmoles, l'osmolarité des tampons n'a aucun effet. Au-delà, et jusqu'à 420 milliosmoles, on observe une baisse significative (P < 0, 001) de la motilité. On obtient un effet biphasique sur la motilité en augmentant la concentration de glucose dans le dilueur (30, 85, 140, 195, 250 mM) avec un maximum pour 85 mM. À cette concentration, la motilité est plus élevée avec le milieu contenant du glucose et du fructose qu'avec ceux contenant du lactose, du sucrose ou du tréhalose (P < 0,001). L'addition de jaune d'œuf (optimum à 13,5% vlv; P < 0,05), la centrifugation des dilueurs (P < 0,01), l'utilisation d'un taux de dilution peu élevé (3 ou 6 fois ; P < 0,05) et la congélation en pastilles plutôt qu'en minitubes ou en minipaillettes (P < 0,001) améliorent la motilité et l'intégrité de l'acrosome des spermatozoïdes congelés dans des milieux contenant un tampon amphotère. Cette étude montre donc que les tampons amphotères sont plus efficaces que le tampon tris-citrate pour les dilueurs utilisés pour la congélation du sperme de bélier.bélier / mobilité l acrosome / sperme congelé / dilueur / tampon * Current address:

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Cationic extracts of egg yolk and their effects on motility, survival and fertilising ability of bull sperm

Cited by 35 publications

References 15 publications

Low-Density Lipoprotein Fraction from Hen’s Egg Yolk Decreases the Binding of the Major Proteins of Bovine Seminal Plasma to Sperm and Prevents Lipid Efflux from the Sperm Membrane1

Low-Density Lipoprotein Fraction from Hen’s Egg Yolk Decreases the Binding of the Major Proteins of Bovine Seminal Plasma to Sperm and Prevents Lipid Efflux from the Sperm Membrane1

Major Proteins of Bovine Seminal Plasma Bind to the Low-Density Lipoprotein Fraction of Hen's Egg Yolk1

In vitro evaluation of zwitterion buffers in diluents for freezing ram spermatozoa

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