In vitro maturation and fertilization techniques for assessment of semen quality and boar fertility.

Abstract

The reliability of using different in vitro-derived measures of sperm quality to predict boar fertility was examined. On three occasions during a 20-wk period of breeding, special collections of the first sperm-rich fraction of the ejaculate from six boars were carried out. After in vitro capacitation procedures, three dilutions (5 x 10(5), 1.25 x 10(5), and 3.125 x 10(4) sperm/mL) of these semen samples were used in a standardized in vitro fertilization (IVF) test with oocytes recovered from prepubertal slaughterhouse ovaries and matured in vitro. Routine assessments of sperm motility, concentration, and morphology were also carried out for all collections used for AI during the 20-wk period. Semen from the same ejaculate, processed according to normal commercial practice using the AndroHEP extender, was used to inseminate equal numbers of recently weaned sows with either 3 x 10(9) or 2 x 10(9) total sperm, three times during the estrous period. Data from a total of 444 sows were used to determine boar fertility; between 12 and 54 sows were bred with each semen dose across the six boars. All measures of sperm fertilizing ability in vitro were different among boars (all P < .05) and use of different semen dilutions for IVF allowed further discrimination of apparent sperm quality among boars. The laboratory evaluation of semen collected during the period of breeding indicated effects of boar on ejaculate volume, total number of sperm per ejaculate, motility, and the percentage of sperm with normal morphology (all P < .01). Sperm dose used in AI had no effect on farrowing rate (80.7 vs 81.5%), but the lower AI dose resulted in a reduction (P < .05) in total numbers born (10.8 vs 10.0). For all three semen dilutions, estimated potential embryo production rate accounted for up to 70% of the variation in litter size obtained with 3 x 10(9) sperm per AI dose, and the number of sperm attached per oocyte was a major factor accounting for variation in litter size obtained with 2 x 10(9) sperm per AI dose. These IVF variables may, therefore, be effective indicators of boar sperm quality for use in AI. With 2 x 10(9) sperm per AI dose, the percentage of sperm with normal morphology also explained a large part of the variance in litter size born (R2 = .59), indicating that morphological characteristics are a useful measure of semen quality.

Seminal Plasma Proteins as Potential Markers of Relative Fertility in Boars

“…Ejaculates were collected into a series of sterile, prewarmed 15-mL Falcon tubes (VWR Canlab, Mississauga, Canada) as described by Xu et al (1996Xu et al ( , 1998 (Figure 1), and 3 fractions were defined on the basis of sperm concentration (Ruiz-Sá nchez et al, 2006). Briefly, tubes containing the first SpermRich fraction were identified both visually and using a calibrated colorimeter (model 254; Sherwood Scientific Ltd, Cambridge, United Kingdom).…”

Effects of skim-milk supplementation on the quality and penetrating ability of boar semen after long-term preservation at 15 °C

“…Therefore, IVF seems to be the most informative method for assessing the penetrating ability of sperm (Xu et al, 1998). In the present study, we found that the supplementation of skim milk had no significant effects on the penetrating ability and development to blastocysts of oocytes after IVF using sperm preserved for two weeks, regardless of the con-centration of skim milk.…”

Interferência da condição climática na integridade de espermatozoides ovinos submetidos à criopreservação

“…Siqueira et al (2007) avaliaram a correlação da motilidade progressiva com a taxa de prenhez em fêmeas bovinas e constataram que não houve interferência da motilidade sobre a taxa de prenhez ou correlação positiva entre essas duas características. Xu et al (1998) avaliaram a importância da motilidade, concentração e morfologia na inseminação de fêmeas suínas e observaram que a alta motilidade não foi significativa para determinar o aumento na taxa de prenhez, e que a baixa concentração espermática diminuiu o tamanho da leitegada, e a qualidade morfológica dos espermatozoides conferiu maior fertilidade.…”