The fertilizing capacity of epididymal spermatozoa in the pig

Abstract

In all mammals studied so far, with the possible exception of man, it has been shown that sperm cells emerging from the testis have to pass through at least part of the epididymis before they acquire the ability to fertilize (Bedford, Calvin & Cooper, 1973;Bedford, 1974).The literature regarding the fertilizing capacity of spermatozoa collected from different segments of the epididymis in laboratory animals has been summarized by Paufler & Foote (1968) and Orgebi n\x=req-\ Crist (1969). Little information is available for the large domestic species although bulls have been successfully inseminated with spermatozoa from the cauda epididymidis (Lardy & Ghosh, 1952;Barker, 1954;Igboeli & Foote, 1968).The present experiments were therefore conducted to examine the fertilizing capacity of spermatozoa from different regions of the epididymis in the domestic pig.Text- fig. 1. Diagram showing the segments into which the boar epididymis was divided.Epididymides were obtained by castrating sexually rested 7-24-month-old German Landrace boars under sodium pentobarbital anaesthesia. Each epididymis was divided into segments (Text- fig. 1). Initially, the segments were the caput, corpus, proximal and distal cauda epididymidis. In subsequent experiments the distal 1 cm of the corpus (Corpus 2), the most proximal (Cauda 1), and the terminal (Cauda 4) portion of the cauda were studied. Each segment was placed in a fine-meshed plastic sieve, submerged in physiological saline at room temperature, and minced gently but thoroughly with fine scissors to provide a suspension of largely intact spermatozoa almost free of contamination with blood or other tissue. Suspensions from similar epididymal segments of several boars were pooled to eliminate individual boar effects.Sperm density was determined by counting two representative samples taken from each suspen¬ sion. After diluting the samples 5-10 times depending on sperm density, haemocytometers were filled and placed in a moist atmosphere for 5 min before counting commenced. Insemination doses of 120 ml, each containing a minimum of 5 IO9 spermatozoa, were prepared by adding saline. Process¬ ing time in the laboratory was about 2 hr and the time between castration and insemination was 4-6 hr.For the inseminations, prepubertal Landrace gilts weighing about 75-85 kg were given a single i.m. injection of a combination of 400 i.u. PMSG and 200 i.u. HCG (PG 600: Intervet International), and inseminated without regard to oestrous symptoms on Days 4 and 5 after the injection. The animals were killed 3-4 weeks after insemination and the ovaries and uterine contents inspected.Of the 141 gilts treated, 119 (84%) responded to the gonadotrophin treatment with 5 or more ovulations, as judged by counts of CL, and were included in the experiment.

Observations on the motility and fertilizing ability of ram epididymal spermatozoa

“…As in rodents (Bedford, 1975 ; Orgebin-Crist, Danzo and Davies, 1975) and in the boar (Holtz and Smidt, 1976 ;Hunter, Holtz and Henfrey, 1976), ram spermatozoon fertilizing ability and motility develop in the distal corpus epididymis ; fertilizing ability was assessed by the number of pregnancies at 18 days post-insemination (Terqui and Thimonier, 1974). But the lambing results (only 5 ewes lambing/8 ewes pregnant) suggest that some embryonic mortality occurred after fertilization with spermatozoa from the corpus epididymis ; this was not observed with spermatozoa from the cauda epididymis (20 lambing ewes/20 pregnant ewes).…”

“…Embryonic mortality was observed only after insemination with spermatozoa from the epididymal corpus: 1/1 and 2/7 ewes pregnant at 18 days after insemination with spermatozoa from the middle and distal corpus did not lamb, but the level of embryonic mortality was 0/8 and 0/12 in the ewes inseminated with spermatozoa from the proximal and distal cauda of the epididymis, respectively. Discussion.As in rodents (Bedford, 1975 ; Orgebin-Crist, Danzo and Davies, 1975) and in the boar (Holtz and Smidt, 1976 ;Hunter, Holtz and Henfrey, 1976), ram spermatozoon fertilizing ability and motility develop in the distal corpus epididymis ; fertilizing ability was assessed by the number of pregnancies at 18 days post-insemination (Terqui and Thimonier, 1974). But the lambing results (only 5 ewes lambing/8 ewes pregnant) suggest that some embryonic mortality occurred after fertilization with spermatozoa from the corpus epididymis ; this was not observed with spermatozoa from the cauda epididymis (20 lambing ewes/20 pregnant ewes).…”

“…In the sow, pregnancies have been obtained after insemination of boar epididymal spermatozoa (Holtz and Smidt, 1976 ;Hunter, Smidt and Henfrey, 1976). Fertilizing ability in this species also first appeared in spermatozoa from the corpus epididymis.…”

In vivo fertilization after initiation of sperm motility in the hamster epididymis

“…They mature progressively during their passage through the epididymis and show increasing motility and capacity for fertility (Orgebin-Crist, 1967 ; Horan and Bedford, 1972 ;Holtz and Smidt, 1976).…”

Lectin-Binding Characteristics of Extracts from Epididymal Boar Spermatozoa.

“…However, few attempts have been made so far to reveal maturation-dependent changes in the lectin affinity for spermatozoa in boars, although the detailed lectin-binding characteristics of sperm components as well as of sperm oar spermatozoa gradually become mature during epididymal transit and then are stored in B the cauda epididymidis until ejaculation [1,2]. The sperm maturation is believed to result from the exposure of luminal spermatozoa to the regionspecific environment within the epididymal duct produced by epithelial secretion and absorption [3,4] and, includes changes in motility [5,6], me-surface has been examined by the lectin blotting technique after sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) [15,16], the analysis via fluorescence or electron microscopy [17,18] and the flow cytometric analysis [19] in other species (e.g.…”