The relationship of infertility to antibody production in the uterovaginal sperm storage tubules of turkey breeder hens

Investigation of the impact of gut microbiotas on fertility of stored sperm by types of hens

Owing to the practical interest in understanding duration of fertility (DF) to reduce the cost of producing hatching eggs by decreasing the frequency of artificial insemination, as well to uncover the mechanism of the estrogen-gut microbiome axis, elucidating the interaction between the maternal microbiome and the function of sperm storage tubules (SST) has become important for revealing the DF in laying hens. In this study, we investigated the compositional, structural, and functional differences in gut microbiomes between hens with high (HSST, n = 8) and low SST activity (LSST, n = 10) by performing phenotypic selection from approximately 400 individual hens based on their DFs. Their cecal microbial communities were analyzed by sequencing the V4 region of the 16S rRNA gene. The microbiome abundance estimators from the ceca of HSST and LSST hens were not significantly different at the phylum and genus taxonomic levels, although the relative abundances for the phylum Firmicutes and the genus Lactobacillus were higher in the HSST group. Furthermore, some taxonomic levels of bacteria expressing the components of several metabolic pathways differed between the HSST and LSST groups. Moreover, predicting functional microbiomes by Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that certain pathways, such as the metabolism of carbohydrates and protein, cellular processes, and organismal systems, of the HSST group exhibited higher expression of genes associated with bioactivity and energy biosynthesis than those in the LSST group. Our results may provide insights into hen-microbe interactions with respect to DF and will be useful in establishing a strategy for new research to uncover the functional regulation of SST in laying hens.

Sperm success and immunity

The moment of the fertilization of an egg by a spermatozoon-the point of "sperm success"-is a key milestone in the biology of sexually reproducing species and is a fundamental requirement for offspring production. Fertilization also represents the culmination of a suite of sexually selected processes in both sexes and is commonly used as a landmark to measure reproductive success. Sperm success is heavily dependent upon interactions with other key aspects of male and female biology, with the immune system among the most important. The immune system is vital to maintaining health in both sexes; however, immune reactions can also have antagonistic effects on sperm success. The effects of immunity on sperm success are diverse, and may include trade-offs in the male between investment in the production or protection of sperm, as well as more direct, hostile, immune responses to sperm within the female, and potentially the male, reproductive tract. Here, we review current understanding of where the biology of immunity and sperm meet, and identify the gaps in our knowledge.

Relationship between reproductive performance and immunity in Taiwan country chickens

Two experiments were conducted to investigate the relationships among reproductive performance, serum gamma-globulin level, carbon clearance ability, and immune responses to phytohemagglutinin and SRBC in the Taiwan Country chicken. In Experiment 1, 480 pullets from 82 sires and 204 dams were used to evaluate the relationship between reproductive performance and immunity. In Experiment 2, 480 pullets, offspring from 55 sires and 173 dams expressing a high or low percentage of serum gamma-globulin and their reciprocal crosses, were used to examine if the level of serum gamma-globulin is associated with reproductive performance and immunity. Results of these experiments indicated that 1) the Taiwan Country chicken had relatively high serum gamma-globulin level compared with those in other reports, 2) serum gamma-globulin level in the Taiwan Country chicken is heritable with an estimate around 0.3 to 0.4, and 3) the high serum gamma-globulin level is genetically associated with low fertility.

Localisation of MHC class II, lymphocytes and immunoglobulins in the oviduct of laying and moulting hens

1. Our aim was to determine the presence and numbers of immunocompetent cells in the oviduct of laying and moulting hens. Immunocompetent cells were localised by immunocytochemistry throughout the entire length of the oviduct. 2. In laying birds, MHC class II+ cells were observed in the subepithelial and middle part of the stroma of all oviducal segments and the mucosal epithelium of the infundibulum and vagina. CD3+ cells were also localised in subepithelial and middle part of stroma as well as in mucosal epithelium of each oviducal segment. Bu-lb+ and IgG+ cells were also observed in the epithelium and subepithelial and middle part of the stroma of all oviducal segments, though stroma of the magnum, isthmus and uterus contained few Bu-lb+ cells. IgA+ cells were observed only in the mucosal epithelium of the magnum in small numbers. 3. In moulting hens, there were few numbers of immunocompetent cells in the mucosal epithelium of each oviducal segment, although CD3+ cells were observed in the infundibulum and vagina. In the subepithelial stroma, the populations of MHC class II+ cells in the infundibulum, magnum and uterus, CD3+ cells in the infundibulum and vagina, as well as IgG+ cells in each oviducal segment except for isthmus were smaller than in laying hens. In contrast, the number of immunocompetent cells in the middle part of stroma of moulting hens were equal to or greater than in laying hens. 4. These results suggest that the oviducal immune function is active in the surface tissues of the mucosa in laying hens, whereas it is reduced in moulting hens.

Evidence for a species-specific barrier to sperm transport within the vagina of the chicken hen

Following their insemination into the vagina of chicken hens, turkey spermatozoa did not appear to reach the ovum within the upper magnum or infundibulum and were only occasionally found within the sperm storage tubules at the uterovaginal junction. Turkey spermatozoa were able to populate chicken uterovaginal sperm storage tubules as (or more) efficiently as fowl spermatozoa in uterovaginal junction tissue in vitro. They also populated uterovaginal junction sperm storage tubules in vivo after insemination directly into the uterovaginal region. Thus, a barrier to foreign spermatozoa appears to exist within the vagina of the chicken and not at the level of the uterovaginal junction sperm storage tubules. The nature of this barrier is not known; however it can be shown that while chicken and turkey spermatozoa have similar morphological features and motility characteristics, they have distinct surface antigenicity. Recognition of surface antigenicity by a localised immunological mechanism may be the basis of sperm selection within the hens vagina.

Genetic influences on seasonal decline in the fertility of female turkeys

Daughter-dam pairs of white, large-bodied, turkey breeder hens (108) were reared under similar husbandry conditions, and their egg production and fertility were monitored from the onset of lay for 6 mo. On a monthly basis, percentage fertility was compared by daughter-dam regressions to estimate heritabilities. The heritability estimates were 18.36, and 38%, respectively, for the 2nd, 3rd, and 4th mo of lay; but no estimates could be made for Months 1, 5, or 6. The heritability of percentage fertility for Months 2, 3, and 4 combined was 42%. The proportion of hens that remained above 75% fertility declined each month for both dams and daughters, except in one case. Thus, the seasonal decline in fertility appears to have a genetic component.

Effects of oviductal trauma on humoral anti-sperm antibody production and fertility in turkey breeder hens

Varying degrees of oviductal trauma were induced in turkey breeder hens during artificial insemination to determine the effects on humoral anti-sperm antibody production and fertility. Two experiments were completed. Mode of artificial insemination had no effect on fertility or the production of serum anti-sperm antibodies in either experiment. It was concluded that no relationship exists between serum anti-sperm antibody titers and fertility.