Diluents for the Preservation of Ram Spermatozoa I. Diluents Used At 37°C and 5°C Containing Casein

Abstract

SummaryRam semen was diluted 40-to 50-fold in various synthetic diluents and the motility of the spermatozoa scored after incubation at 37°C and after slow cooling to, and storage at, 5°C. Levels of potassium above 10 m-equiv. were deleterious at both temperatures. the addition of 5 m-equiv. calcium depressed motility at 37°C but improved survival rates of spermatozoa stored at 5°C. The inclusion of 6 m-equiv. magnesium in diluents had no detectable effect on motility scores.Replacement of the sodium chloride component (123 mM) of a diluent buffered with 20 mM phosphate buffer with an isosmotic lactose solution showed that diluents with a content of this sugar ranging from 61 to 246 mM were superior at both 37 and 5°C to that containing 123 mM sodium chloride and no lactose. Diluents containing 184 mM fructose, glucose, lactose, or sucrose and 31 mM sodium chloride were all better for the storage of ram spermatozoa at 5°C than the diluent containing 123 mM sodium chloride.Motility scores of spermatozoa incubated at 37°C were slightly, but significantly, lower in diluents containing 2·0 % casein than in those with 0·5 % casein. Scores at 5°C showed that 2· 0% casein gave much better survival than O· 5% casein.

Milk Caseins Decrease the Binding of the Major Bovine Seminal Plasma Proteins to Sperm and Prevent Lipid Loss from the Sperm Membrane During Sperm Storage1

“…It is remarkable that skimmed milk is also used to store semen from other mammals such as ram (reviewed in [45]), goat (reviewed in [46]), stallion (reviewed in [47]), buffalo (reviewed in [48]) and dog [49]. In addition, it has been shown that casein micelles isolated from milk can also protect sperm from stallion, goat and ram during storage [6,9,10,12,13]. Interestingly, proteins that are deleterious to sperm storage (BSP protein homologs that stimulate lipid loss from the sperm membrane) are also present in the seminal plasma of those species (reviewed in [19]).…”

“…Basically, casein micelles are constituted of a hydrophobic core of a and b caseins surrounded by j caseins [8]. It has been shown that casein micelles isolated from milk can protect stallion, goat, ram, and bull sperm during storage at 4-58C [6,[9][10][11][12][13]. In addition, casein micelles can protect bull sperm during freezing in the presence of glycerol [5].…”

Effet de la fréquence de récolte et des milieux de dilution sur la qualité du sperme de taureau de race Borgou

“…En revanche, pour une conservation à +5 °C, l'addition d'autres sources d'énergie n'est pas reconnue nécessaire car Ehlers et Erb (1959) ont montré que la chute de la fertilité de 5,5% pour les dilueurs lactés avec le fructose contre 4,1% pour les dilueurs sans fructose. Par ailleurs, en séparant par une dialyse les parties à faibles poids moléculaires du lait, son effet bénéfique à +37 °C sur les spermatozoïdes du bélier et du taureau est signalé (Garcia et Graham, 1987) et des teneurs de 0,5% et 2% de caséine dans le lait sont optimales pour une conservation respective à +37 °C et à +5 °C (Martin, 1966). L'effet protecteur du lactosérum sur la semence est reconnu notamment pour le buffle (Bhosrekar et Ganguli, 1971) et pour conserver à +5°C, la fertilité des semences pendant plusieurs jours, l'addition de glycérol au dilueur lacté est recommandée (Jondet, 1980).…”

“…Qu'un seul maillon de la technologie de sperme (récolte, dilution, conservation et insémination) soit défectueux et le résultat final de l'insémination artificielle, c'est à dire la fécondation, peut être compromise (Jondet 1980). C'est à juste titre que les milieux suivants sont testés pour la conservation de semence des ruminants : les milieux lactés (Martin, 1966 ;Leboeuf et al, 1998) ; les milieux à base de jaune d'oeuf (Iritani et Nishikawa., 1961, 1963Jondet, 1980 ;Moussa et al, 2002) ; les milieux glucosés (Palmer, 1984) ; les milieux à base de lait de coco (Norman et al, 1962). L'importance de la fréquence de récolte est explorée depuis très longtemps, pour valoriser la production de semence dans les centres d'insémination artificielle (Jondet, 1980).…”

Effects of Composition of Diluent, Method of Addition of Glycerol, Freezing Rate, and Storage Temperature on the Revival of Ram Spermatozoa After Deep-Freezing

“…Various preparations of cow milk have been used in diluents for deep-freeziug ram spermatozoa and satisfactory revival on thawing has been recorded (Blackshaw 1960a(Blackshaw , 1960bFirst et al 1961;Martin 1961;Jones and Martin 1965). More recently, synthetic diluents containing sugars and electrolytes, together with small proportions of preparations from milk or egg yolk, have been developed which give a degree of protection to ram spermatozoa during freezing and thawing which is comparable to, or in some cases exceeds, that given by diluents based on heated milk or fresh egg yolk (Jones 1965;Jones and Martin 1965).…”