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United States Department of Agriculture

Agricultural Research Service

Research Project: GENOMIC REGULATION OF SEASONAL INFERTILITY IN SWINE

Location:

2011 Annual Report


1a.Objectives (from AD-416)
Objective 1: Identify adipose tissue genes and physiological pathways underlying variation in seasonal infertility in swine.

Sub-objective 1.A: Identify physiological pathways that underlie the relationship between reproductive losses due to seasonal infertility. Sub-objective 1.B: Identify changes in adipose tissue gene expression underlying variation in seasonal infertility in swine.

Objective 2: Define physiological factors contributing to gastrointestinal-microbial population and immune function that are associated with seasonal infertility in sows.

Sub-objective 2.A: Identify microbial popoulation changes and sensitivity to antimicrobials associated with seasonal infertility. Sub-objective 2.B: Characterize functional changes in systemic and tissue level inflammatory and immune cells that are associated with seasonal infertility in the sow.

Objective 3: Determine if a relationship exists between reproductive losses due to seasonal infertility and adipocyte function, metabolism and uterine function.

Sub-objective 3.A: Identify genes that are related to physiological pathways that are associated with seasonal infertility and associated adipocyte function and metabolism. Sub-objective 3.B: Identify genes that are related to physiological pathways that are associated with seasonal infertility and pregnancy failure.

Objective 4: To map patterns of gene expression that underlie adipose tissue deposition and identify intervention control points to reduce fat deposition.


1b.Approach (from AD-416)
Seasonal infertility is proposed to be due to many stressors such as social environment, management, nutrition, thermal environment, and photoperiod. These factors affect neuroendocrine function of the sow, resulting in reduced fertility. It is well established that level of nutrition during lactation affects body condition and weaning-to-estrus interval. A manifestation of these stressors is an alteration in metabolic mass, a reduction in food intake and its correlated metabolic rate, which may be the triggering mechanism. Thus, seasonal infertility may also in part be due to reduced body fat and altered adipocyte function and secretion of regulatory proteins. An integrated and multidisciplinary approach, combining microarray technology with the study of endocrinology, adipocyte function, immune function and gastrointestinal microbial ecology in order to elucidate the mechanisms that contribute to seasonal infertility in the sow. This systems approach will provide an unprecedented opportunity to identify important genes and gene interactions and physiological pathways contributing to variation in seasonal fertility.


3.Progress Report
A chicken ontogeny study was conducted to determine the influence of age on chicken adipose tissue gene expression. Abdominal adipose tissue samples obtained from ten broiler chickens at 3, 4, 5, and 6 weeks of age were prepared for real time gene expression analysis. Microarray analysis was combined with the analysis of specific genes to examine the age associated changes in global gene expression in chicken adipose tissue. Results of the study indicated that chicken adipose tissue expresses many of the genes expressed by organs involved in the immune response. These findings are important because chicken adipose tissue may play a role in the immune response and may play a role in disease resistance.

The ontogeny of chicken adipose tissue gene expression. In this study, total RNA was collected from abdominal adipose tissue samples obtained from ten broiler chickens at 3, 4, 5, and 6 weeks of age and prepared for gene microarray analysis with Affymetrix GeneChip® Chicken Genome Arrays (Affymetrix, Santa Clara, CA) and specific gene analysis with custom-designed primers and probes. Studies of the gene expression of cytokines and associated genes in chicken adipose tissue were initiated since the discovery of leptin has shown in many animal species that adipose tissue derived factors can influence growth and physiology. Microarray results indicated 333 differentially expressed genes between 3-6 wks, 265 genes between 4-6 weeks and 42 genes between 3-4 wks differentially expressed. Enrichment scores of Gene ontology Biological Process categories indicated strong age up-regulation of genes involved in the immune system response. In addition to microarray analysis, specific gene analysis was used to confirm the influence of age on the expression of adipose tissue of immune system response genes and several genes related to growth. Between 3 and 6 weeks of age the leptin receptor gene expression decreased (P < 0.05) with age while expression of several genes increased significantly (P < 0.05). Furthermore, a newly discovered adipose tissue gene called visfatin increased in expression (P < 0.001) between 4 and 6 weeks of age. This is the first demonstration of age related changes in cytokine gene expression in chicken adipose tissue.


4.Accomplishments
1. The ontogeny of chicken adipose tissue gene expression. In this study, total RNA was collected from abdominal adipose tissue samples obtained from ten broiler chickens at 3, 4, 5, and 6 weeks of age and prepared for gene microarray analysis with Affymetrix GeneChip® Chicken Genome Arrays (Affymetrix, Santa Clara, CA) and specific gene analysis with custom-designed primers and probes. Studies of the gene expression of cytokines and associated genes in chicken adipose tissue were initiated since the discovery of leptin has shown in many animal species that adipose tissue derived factors can influence growth and physiology. Microarray results indicated 333 differentially expressed genes between 3-6 wks, 265 genes between 4-6 weeks and 42 genes between 3-4 wks differentially expressed. Enrichment scores of Gene ontology Biological Process categories indicated strong age up-regulation of genes involved in the immune system response. In addition to microarray analysis, specific gene analysis was used to confirm the influence of age on the expression of adipose tissue of immune system response genes and several genes related to growth. Between 3 and 6 weeks of age the leptin receptor gene expression decreased (P < 0.05) with age while expression of several genes increased significantly (P < 0.05). Furthermore, a newly discovered adipose tissue gene called visfatin increased in expression (P < 0.001) between 4 and 6 weeks of age. This is the first demonstration of age related changes in cytokine gene expression in chicken adipose tissue.


Review Publications
Barb, C.R., Hausman, G.J., Kraeling, R.R. 2010. Luteinizing hormone secretion as influenced by age and estradiol in the prepubertal gilt. Animal Reproduction Sciences. 122:324-327.

Poulos, S.P., Hausman, G.J., Dodson, M. 2010. Cell line models of differentiation: preadipocytes and adipocytes. Experimental Biology and Medicine. 235(10):1185-1193.

Last Modified: 10/1/2014
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