Fertility In Artificial Insemination Research Articles

Differences in sperm functionality and intracellular metabolites in Norwegian Red bulls of contrasting fertility

In the dairy breeding industry, prediction of bull fertility in artificial insemination (AI) is important for efficient and economically sustainable production. However, it is challenging to identify bulls with superior fertility applying conventional in vitro sperm assays. In the present study, sperm functionality was investigated to identify a multivariate model that could predict fertility. Two groups of young Norwegian Red bulls were selected, one with inferior fertility (18 bulls) and one with superior fertility (19 bulls) based on non-return rate after 56 days (NR56). Frozen-thawed semen doses were analysed for sperm chromatin integrity, viability, acrosome integrity, motility, and ATP content. A targeted approach was used to study intracellular concentrations of amino acids and trace elements in viable sperm cells. Significant differences between the two groups of bulls were observed, both for sperm functional attributes and intracellular concentrations of metabolites. Pearson correlation analyses indicated a negative relationship between NR56 and chromatin integrity parameters, DNA fragmentation index (DFI) and high DNA stainability (HDS). Several motility parameters correlated positively with NR56. The concentrations of cysteine and glutamic acid in sperm cells correlated negatively with NR56, while the concentrations of aspartic acid, leucine and serine showed a positive NR56-correlation. The sperm intracellular concentrations of the trace elements Fe, Al and Zn, correlated negatively with NR56. Correlations were observed between several sperm parameters and metabolites. Stepwise multiple regression analysis indicated that the best predictor of NR56 was a model containing %DFI, together with the intracellular sperm concentration of aspartic acid, Fe and Zn. This model explained 59% of the variability in NR56.

Effect of frequency of collection on seminal characteristics of White Pekin duck

Abstract Objective To determine an optimum frequency of semen collection, so as to improve the efficacy of artificial insemination techniques and selective breeding programmes in duck farming. Methods Thirty two ejaculates were collected by abdominal massage method from two groups of drakes, with 10 in each, at one day and two day intervals respectively. Routine seminal attributes such as volume, colour, pH, spermatozoa concentration, number of spermatozoa per ejaculate, individual motility, live sperm percentage, total sperm abnormalities and time taken to reduce Methylene blue (MBRT) were studied for comparison of their values in one day and two days of interval of semen collection. Twenty female laying ducks maintained for examining the fertility percent were regularly inseminated with 0.1 mL of neat pooled semen for fertility test. Results The test of significance indicated a significant decrease ( P P P Conclusion Collection of semen at two days intervals is recommended for enhancing fertility in artificial insemination of duck. The methylene-blue reduction test, along with spermatozoa count and initial motility estimates were reported to be better indicator of semen quality.

Protein expression pattern of PAWP in bull spermatozoa is associated with sperm quality and fertility following artificial insemination

Post-acrosomal WW-domain binding protein (PAWP) is a signaling molecule located in the post-acrosomal sheath (PAS) of mammalian spermatozoa. We hypothesized that the proper integration of PAWP in the sperm PAS is reflective of bull-sperm quality and fertility. Cryopreserved semen samples from 298 sires of acceptable, but varied, fertility used in artificial insemination services were analyzed using immunofluorescence microscopy and flow cytometry for PAWP protein. In normal spermatozoa, PAWP fluorescence formed a regular band around the proximal PAS. Anomalies of PAWP labeling in defective spermatozoa were reflected in flow cytometry by varied intensities of PAWP-induced fluorescence. Distinct sperm phenotypes were also identified, including morphologically normal and some defective spermatozoa with moderate levels of PAWP; grossly defective spermatozoa with low/no PAWP; and defective spermatozoa with high PAWP. Analysis by ImageStream flow cytometry confirmed the prevalence of abnormal sperm phenotypes in the spermatozoa with abnormal PAWP content. Live/dead staining and video recording showed that some abnormal spermatozoa are viable and capable of progressive motility. Conventional flow-cytometric measurements of PAWP correlated significantly with semen quality and fertility parameters that reflect the sires' artificial insemination fertility, including secondary sperm morphology, conception rate, non-return rate, and residual value. A multiplex, flow-cytometric test detecting PAWP, aggresomes (ubiquitinated protein aggregates), and acrosomal integrity (peanut-agglutinin-lectin labeling) had a predictive value for conception rate, as demonstrated by step-wise regression analysis. We conclude that PAWP correlates with semen/fertility parameters used in the cattle artificial insemination industry, making PAWP a potential biomarker of bull fertility.

The Roles of Vitamin A for Cytoplasmic Maturation of Bovine Oocytes

Vitamin A is one of the micronutrients which have been implicated in cattle reproduction. In cattle, ingested vitamin A, mainly as beta-carotene (BC) from forages and retinol ester from formula feed, is metabolized and transported to the oocytes and cumulus-granulosa cells in ovarian follicles through binding to various interacting molecules. The active form of vitamin A, retinoic acid (RA), functions as a regulator of gene expression in these targets. Early research showed the positive effects of vitamin A supplementation on bovine fertility in artificial insemination, and several studies on effects of vitamin A metabolites used in other artificial reproductive techniques (ART), including superovulation, ovum pick up, and in vitro maturation culture have provided evidence for the specific roles of vitamin A in oocyte cytoplasmic maturation (acquisition of developmental competence of oocytes during their meiotic maturation period for the embryonic development after fertilization). BC may enhance cytoplasmic maturation by its antioxidant properties which cannot be replaced by RA. Furthermore, RA may promote cytoplasmic maturation of bovine oocytes via its modulatory effects on the gene expression of gonadotrophin receptors, midkine, cyclooxygenase-2, and nitric oxide synthase in cumulus-granulosa cells.

Semen assessment, fertility and the selection of Hereford bulls for use in AI.

Nineteen young Hereford bulls were used to study the relationship between semen characteristics and fertility in artificial insemination following 15 320 inseminations. Seven measures of sperm motility, morphological abnormalities, the release of hyaluronidase, ATP content and sperm head measurements were examined as predictors of fertility (49-day fixed-interval non-return rate). Two assessments of motility, three categories of abnormal spermatozoa, acrosomal changes and the release of hyaluronidase had predictive power. Multiple regression analysis showed that a combination of sperm motility after dilution in saline, motility after thawing and the proportion of coiled tails and proximal protoplasmic droplets provided the best prediction of fertility and allowed bulls to be ranked in order of observed non-return rate (%) with a Spearman correlation better than +0.80.

Heritability of Semen Quantity, Concentration and Motility in White Rock Roosters, and Their Genetic Correlation with Rate of Gain

MALE fertility, by virtue of its influence on net chick production per laying hen, and hence on chick costs, is of considerable importance in broiler production. A number of papers have been published indicating a positive relationship between semen characteristics and fertility in artificial insemination (for reviews see Lorenz, 1959; Smyth and Jeffrey, 1960; and Lake, 1962). It has also been shown that a slight positive correlation may exist between semen characteristics and fertility in natural mating as well (McDaniel and Craig, 1959; Soller et al., 1965; Szumowski, 1963). It is of interest, therefore, to estimate the heritability of various semen traits. Such estimates will provide information on the possibility of improving semen characteristics, and hence fertility, by selection. In view of the strong selection for rate of gain carried out in broiler lines, it is also of interest to estimate the genetic correlation between semen characteristics and rate of…

Minimal volume of semen and number of sperm for fertility in artificial insemination of swine.

Forty-six gilts were inseminated with quantities of fresh semen ranging from 0.01 to 20 cc. diluted to a total volume of 50 cc. in a modified Krebs' solution and 40 sows were inseminated with quantities of 1 to 50 cc. of fresh semen diluted to either 50 or 250 cc. In gilts some fertility (29%) was obtained with 0.1 cc. semen and an average fertility of 91% was obtained with 20 cc. semen diluted to 50 cc. In sows fertility was almost as high (42%) with 1 cc. of semen diluted to 50 cc. as it was with 20 cc. of semen diluted to either 50 or 250 cc. (43% in each case). The average fertility per sow was 67% when 50 cc. of semen diluted to 250 cc. was used. Maximum-possible average litter sizes were estimated at 5.7 to 11.8 pigs in gilts and from 4.5 to 13.4 pigs in sows inseminated with different quantities of semen. Sows ovulated 4.6 more eggs, had 11.8 inch longer uterine horns and stayed in heat slightly longer than gilts.