Detrimental Effects of Non-Functional Spermatozoa on the Freezability of Functional Spermatozoa from Boar Ejaculate

In the present study, the impact of non-functional spermatozoa on the cryopreservation success of functional boar spermatozoa was evaluated. Fifteen sperm-rich ejaculate fractions collected from five fertile boars were frozen with different proportions of induced non-functional sperm (0 –native semen sample-, 25, 50 and 75% non-functional spermatozoa). After thawing, the recovery of motile and viable spermatozoa was assessed, and the functional of the spermatozoa was evaluated from plasma membrane fluidity and intracellular reactive oxygen species (ROS) generation upon exposure to capacitation conditions. In addition, the lipid peroxidation of the plasma membrane was assessed by the indirect measurement of malondialdehyde (MDA) generation. The normalized (with respect to a native semen sample) sperm motility (assessed by CASA) and viability (cytometrically assessed after staining with Hoechst 33342, propidium iodide and fluorescein-conjugated peanut agglutinin) decreased (p<0.01) as the proportion of functional spermatozoa in the semen samples before freezing decreased, irrespective of the semen donor. However, the magnitude of the effect differed (p<0.01) among boars. Moreover, semen samples with the largest non-functional sperm subpopulation before freezing showed the highest (p<0.01) levels of MDA after thawing. The thawed viable spermatozoa of semen samples with a high proportion of non-functional spermatozoa before freezing were also functionally different from those of samples with a low proportion of non-functional spermatozoa. These differences consisted of higher (p<0.01) levels of intracellular ROS generation (assessed with 5-(and-6) chloromethyl-20,70-dichlorodihydrofluorescein diacetate acetyl ester; CM-H2DCFDA) and increased (p<0.01) membrane fluidity (assessed with Merocyanine 540). These findings indicate that non-functional spermatozoa in the semen samples before freezing negatively influence the freezability of functional spermatozoa

Sperm Competition, Sperm Numbers and Sperm Quality in Muroid Rodents

Sperm competition favors increases in relative testes mass and production efficiency, and changes in sperm phenotype that result in faster swimming speeds. However, little is known about its effects on traits that contribute to determine the quality of a whole ejaculate (i.e., proportion of motile, viable, morphologically normal and acrosome intact sperm) and that are key determinants of fertilization success. Two competing hypotheses lead to alternative predictions: (a) sperm quantity and quality traits co-evolve under sperm competition because they play complementary roles in determining ejaculate's competitive ability, or (b) energetic constraints force trade-offs between traits depending on their relevance in providing a competitive advantage. We examined relationships between sperm competition levels, sperm quantity, and traits that determine ejaculate quality, in a comparative study of 18 rodent species using phylogenetically controlled analyses. Total sperm numbers were positively correlated to proportions of normal sperm, acrosome integrity and motile sperm; the latter three were also significantly related among themselves, suggesting no trade-offs between traits. In addition, testes mass corrected for body mass (i.e., relative testes mass), showed a strong association with sperm numbers, and positive significant associations with all sperm traits that determine ejaculate quality with the exception of live sperm. An “overall sperm quality” parameter obtained by principal component analysis (which explained 85% of the variance) was more strongly associated with relative testes mass than any individual quality trait. Overall sperm quality was as strongly associated with relative testes mass as sperm numbers. Thus, sperm quality traits improve under sperm competition in an integrated manner suggesting that a combination of all traits is what makes ejaculates more competitive. In evolutionary terms this implies that a complex network of genetic and developmental pathways underlying processes of sperm formation, maturation, transport in the female reproductive tract, and preparation for fertilization must all evolve in concert

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Dietary supplementation of n-3 polyunsaturated fatty acid alters endometrial expression of genes involved in prostaglandin biosynthetic pathway in breeding sows (Sus scrofa)

Not AvailableThe present investigation was designed to study the effect of dietary supplementation of omega-3 (n-3) PUFA on endometrial expression of fertility-related genes in breeding sows. Sixteen crossbred sows were randomized to receive diets containing 4% (wt/wt) flaxseed oil as n-3 PUFA source (TRT group) or isonitrogenous, iso-caloric standard control diet (CON group), starting from the first day of estrus up to 40 days and were artificially bred on the second estrus. Endometrial samples were collected during days 10e11 and 15e16 post-mating for studying relative expression profile of candidate genes viz. Prostaglandin F Synthase (PGFS), microsomal Prostaglandin E Synthase-1 (mPGES-1) and Carbonyl Reductase-1 (CBR-1) using quantitative Real-Time PCR. Expression level of mPGES-1 gene transcript was 2.1-fold higher (P 0.05) during 15e16 days of pregnancy in TRT group as compared to CON group. Relative expression of PGFS gene transcript was significantly lower (P 0.05) of dietary supplementation during 15e16 days of pregnancy. Endometrial mRNA level of CBR1 was significantly lower (P 0.05) was observed subsequently during 15 e16 days of pregnancy as compared to CON group. Collectively, these results indicate that dietary n-3 PUFA supplementation can modulate gene expression of key enzymes in prostaglandin biosynthetic pathway during early gestation, which in turn might have beneficial impact on overall reproductive response in breeding sows. These findings partly support strategic dietary supplementation of plant-based source of n-3 PUFA with an aim to improve overall reproductive performance in sows.Not Availabl

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Not AvailableThe present investigation was designed to study the effect of dietary supplementation of omega-3 (n-3) PUFA on endometrial expression of fertility-related genes in breeding sows. Sixteen crossbred sows were randomized to receive diets containing 4% (wt/wt) flaxseed oil as n-3 PUFA source (TRT group) or iso-nitrogenous, iso-caloric standard control diet (CON group), starting from the first day of estrus up to 40 days and were artificially bred on the second estrus. Endometrial samples were collected during days 10-11 and 15-16 post-mating for studying relative expression profile of candidate genes viz. Prostaglandin F Synthase (PGFS), microsomal Prostaglandin E Synthase-1 (mPGES-1) and Carbonyl Reductase-1 (CBR-1) using quantitative Real-Time PCR. Expression level of mPGES-1 gene transcript was 2.1-fold higher (P  0.05) during 15-16 days of pregnancy in TRT group as compared to CON group. Relative expression of PGFS gene transcript was significantly lower (P  0.05) of dietary supplementation during 15-16 days of pregnancy. Endometrial mRNA level of CBR1 was significantly lower (P  0.05) was observed subsequently during 15-16 days of pregnancy as compared to CON group. Collectively, these results indicate that dietary n-3 PUFA supplementation can modulate gene expression of key enzymes in prostaglandin biosynthetic pathway during early gestation, which in turn might have beneficial impact on overall reproductive response in breeding sows. These findings partly support strategic dietary supplementation of plant-based source of n-3 PUFA with an aim to improve overall reproductive performance in sows.Not Availabl