Brief Summary of Minutes of Annual Meeting

The business meeting was chaired by David Froman using the following outline: (1) a thanks to Dr. Douglas Rhoads, (2) leadership options within S1047, (3) the importance of participation in annual meetings, and (5) options for the location of the 2011 annual meeting. Dr. Mark Mirando provided a NIFA AFRI update by phone. A discussion followed in regard to program priority areas and the recent NIH-NIFA PAR. The chair (David Froman) and secretary/treasurer (Douglas Rhoads) agreed to serve another year. In order to minimize travel costs and maximize participation, participants agreed to have the next annual meeting of S1047 in October of 2011 in State College, PA. Charleston, SC was agreed upon for a backup meeting site.

1. Characterize mechanisms enabling rhythmic regulation of dopaminergic-melatonergic neurons within the hypothalamus of photosensitive turkey hens. 2. Characterize molecular mechanisms affecting egg production in chickens. Broiler breeder hens have the poorest reproductive efficiency of all commercial avian species primarily due to excessive feed intake and adiposity. This decrease in reproductive efficiency is directly associated with severe ovarian dysfunction, including internal and/or double ovulations and reduced fertility of ovulated oocytes. Broiler breeder hens fed ad libitum develop an aberrant (e.g., double) preovulatory hierarchy due to an excessive recruitment of follicles from the prehierarchal cohort (e.g., follicles 6-8 mm in diameter). By comparison, feed-restricted breeder hens demonstrate a comparatively normal number of preovulatory follicles when compared to the Leghorn (laying) hen. It is conceivable that the higher rate at which follicle selection occurs in the highly productive laying hen, compared to the feed-restricted broiler breeder hen, reflects an increased number of follicles available within the prehierarchal cohort. For instance, feed-restricted broiler breeders that lay only 2 to 4 eggs per sequence and show a variable number of skip days between sequences have fewer follicles available within the prehierarchal cohort when compared to full-fed hens that routinely show double hierarchies, or even laying strains with extended laying sequences. Specifically, restricted-fed broiler breeders have significantly (5 to 6) fewer follicles available within the prehierarchal cohort compared to full-fed hens and laying hens. Current studies involve determining the role for Bone Morphogenetic Proteins (BMPs), including BMP2, BMP6, BMP15 and Antimullerian Hormone (AMH) both at Penn State University and in collaboration with Dr. P.A. Johnson at Cornell University. The level of feeding in broiler breeder females also alters early follicular growth (e.g., initial recruitment) and delays puberty. Recent results identify a decrease in the number of small follicles (<2 mm) caused by feed restriction, which is associated with decreased mRNA expression of the BMPs, AMH, BMP6 and BMP15, plus the transcription factors, FOXL2 and GATA4 mRNA. These results, combined with histological correlates, provide evidence of diet and energy-related changes in initial follicle recruitment and gene expression measures. The precise role of adiposity and adipose-derived factors on ovarian dysfunction has not been investigated. Adiponectin, an adipokine hormone, is associated with obesity and metabolic syndrome in humans and rodent models. Adiponectin improves insulin sensitivity and favors carbohydrate utilization while decreasing lipogenesis. Using custom-generated reagents and tools, plasma adiponectin levels were found to be significantly lower in ad libitum fed chickens compared with feed-restricted broiler breeder hens. Furthermore, ad libitum fed broiler breeder hens have significantly lower ovarian and adipose tissue adiponectin mRNA and higher follicle stimulating hormone (FSH) receptor mRNA abundance. The data suggests that visceral adiposity associated with excessive feeding in broiler breeder hens can suppress secretion of adiponectin and alter responses to FSH. The role of adiponectin on metabolism, steroidogenesis and altered responses to FSH in broiler breeder hen ovarian follicular cells are being investigated. Finally, a series of studies has addressed the role of molecular circadian clocks in regulating the development and maturation of ovarian follicles in the domestic chicken. Molecular circadian clocks play key roles in regulating follicular development, most likely through the clocks interactions with metabolic pathways at the level of the granulosa cells. Results suggest that the interactions of clocks located in the ovary, shell gland, and medullary bone aid in the regulation of calcium stores for utilization in eggshell formation. 3. Identify chromosomal regions affecting phenotypic variation in sperm mobility, a primary determinant of male fertility. Rhoads (University of Arkansas) and Froman (Oregon State University) continued their mapping of QTLs affecting sperm mobility in broiler lines. They have confirmed two regions on the Z chromosome and one on chromosome 6 as contributing to sperm mobility phenotype in experimental and commercial lines. KCNMA1 has been identified as a probable candidate gene and is being re-sequenced from high and low mobility males to identify SNPs for SNPlotype assays. Proteomic analysis was performed in collaboration with Dr. Shane Burgess, who directs the MSU Life Science & Biotechnology Institute. Based upon proteome data sets, the glycolytic pathway is compromised within an experimental line of chickens selected for low sperm mobility. However, this line difference was not observed at the level of the testis transcriptome using qPCR. 4. Characterize the mating behavior of contemporary broiler breeders and define the central pathways affecting reproductive behavior. The Kuenzel laboratory found that a particular group of neurons called the medial division, sub-nucleus 2 of the bed nucleus of the stria terminalis (BSTM2) is involved with courtship behavior of male broiler breeders. In contrast, three neural structures were found associated with both consummatory sexual behavior (copulation) and aggressive behavior including the lateral septum, paraventricular nucleus and bed nucleus of the pallial commissure. Two specific groups of neurons were identified within the paraventricular nucleus, one comprising arginine vasotocin (AVT) neurons, homologous to vasopressin neurons in mammals, and the second comprising corticotropin releasing hormone (CRH) neurons. The AVT neurons were shown to project both to the posterior pituitary as well as to the median eminence while CRH neurons projected to the median eminence. The AVT and CRH neurons projecting to the median eminence regulate the release of adrenocorticotropic hormone (ACTH) from corticotropes found in the anterior pituitary. Corticotropes have a specific receptor called the vasotocin 2 receptor (VT2R) that mediate the release of ACTH from the anterior pituitary. The hormone ACTH, in turn, stimulates the adrenal gland to release the stress hormone corticosterone. This neural pathway was verified in the stress response of male broilers.

Froman, D. P., A. J. Feltmann, K. Pendarvis, A. M. Cooksey, S. C. Burgess, and D. D. Rhoads. 2010. A proteome-based model for sperm mobility phenotype. J. Anim. Sci. (in press). Haugen, M. J. and A. L. Johnson. 2010. Bone Morphogenetic Protein 2 inhibits FSH responsiveness in hen granulosa cells. Reprod. 140: 551-558. Kuenzel, W. J., and A. Jurkevich. 2010. Molecular neuroendocrine events during stress in poultry. Poult. Sci. 89:832-840. Kumar, V., J. C. Wingfield, A. Dawson, M. Ramenofsky, S. Rani, and P. Bartell. 2010. Biological clocks and regulation of seasonal reproduction and migration in birds. Physiol Biochem Zool. 83(5):827-35. McFarlane, H. O., N. T. Joseph, S. R. Maddineni, R. Ramachandran, G. Y. Bedecarrats. 2010. Development, validation, and utilization of a novel antibody specific to the type III chicken gonadotropin-releasing hormone. Domestic Animal Endocrinology. (in press). Ocón-Grove, O.M., S. M. Krzysik-Walker, S. R. Maddineni, G. L. Hendricks III, and R. Ramachandran. 2010. NAMPT (Visfatin) in the chicken testis: Influence of sexual saturation on cellular localization, plasma levels, gene and protein expression. Reprod. 139: 217-226. Xie, J., W. J. Kuenzel, N. B. Anthony, and A. Jurkevich. 2010. Subpallilal and hypothalamic areas activated following sexual and agonistic encounters in male chickens. Physiol. Behav. 101:344-359.