Progress 05/15/17 to 05/14/23
Outputs
Target Audience:Scientists (faculty, graduate students, post-doctoral associates) in academia and poultry breeding companies are the target audience for this research to improve the reproductive efficiency of broiler breeder chickens. Changes/Problems:None What opportunities for training and professional development has the project provided?A female undergraduate student (Everlyn Weaver) was trained in our laboratory to conduct both basic and applied research related to commercial poultry production with the goal of improving reproductive efficiency in broiler breeder chickens. In addition, 4 undergraduate students weretrained in our laboratory to conduct research. How have the results been disseminated to communities of interest?Through scientific publications. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The results of the experiments funded under Specific Aim#1 have been published in a peer-reviewed journal (Weaver and Ramachandran, 2020) and are briefly described below. The ovarian follicular hierarchy in broiler breeder chicken ovary is often deranged due to excessive ovarian follicular recruitment, resulting in a condition that resembles polycystic ovary syndrome (PCOS) in women. Metformin is widely prescribed to correct PCOS and has been shown to affect granulosa cell functions in humans and rodent models. The objectives of this study are to determine the effects of metformin on signal transduction pathways, gene expression related to steroidogenesis, and progesterone secretion from granulosa cells isolated from the most recently recruited preovulatory and prehierarchical follicles of broiler breeder chickens. Granulosa cells were treated with 0, 1, 10, or 20 mM of metformin in the presence of recombinant human follicle-stimulating hormone (rhFSH). The abundance of phospho-adenosine monophosphate-activated protein kinase (pAMPK), phospho-acetyl coenzyme-A (pACC), phospho-extracelluar receptor-related kinase (pERK), and phospho-protein kinase B (pAkt) was determined by Western blotting. The expression of genes related to progesterone biosynthesis was quantified by quantitative PCR. Progesterone concentrations in culture media were quantified by ELISA. Metformin treatment did not have an effect on the abundance of pAMPK and pACC in prehierarchical follicles but significantly decreased the abundance of pERK and pAkt in a dose-dependent manner in preovulatory and prehierarchical follicles. The expression of genes related to steroidogenesis such as follicle-stimulating hormone receptor (FSHR), steroidogenic acute regulatory protein (STAR), cholesterol side-chain cleaving enzyme (CYP11A1), and 3-beta hydroxysteroid dehydrogenase (HSD3B1) and progesterone secretion was significantly decreased in response to metformin treatment in a dose-dependent manner. Our data suggest that metformin treatment attenuates progesterone secretion via AMPK-independent pathways in granulosa cells of prehierarchical and preovulatory follicles of broiler breeder hens. Further studies are required to determine if metformin administration could ameliorate ovarian dysfunction in obese broiler breeder hens. The results of the experiments funded under Specific Aims#2 and 3 have been published in a peer-reviewed journal (Weaver and Ramachandran, 2023) and are briefly described below. Broiler breeder hens, the parent stock of commercial broiler chickens, have poor reproductive efficiency associated with aberrant and excessive recruitment of ovarian follicles which results in sub-optimal egg production, fertility, and hatchability. The reproductive dysfunction observed in these hens resembles polycystic ovary syndrome in women, a condition wherein metformin is prescribed as a treatment. The main objectives of this study were to determine the effect of metformin on body weight, abdominal fat pad weight, ovarian function, and plasma steroid hormone concentrations. Broiler breeder hens were treated with 0, 25, 50, or 75 mg/kg body weight of metformin mixed in the diet for 40 weeks (n = 45 hens/treatment; 2565 weeks of age). At 65 weeks of age, hens that received the highest dose of metformin had significantly lower body and abdominal fat pad weights (P < 0.05) than the control. Metformin treatment, at all levels, normalized the preovulatory and prehierarchical ovarian follicular hierarchy. Metformin (50 or 75 mg/kg body weight) significantly increased the total number of eggs laid per hen during the entire production period and these hens had significantly greater fertility and hatchability at 65 weeks of age compared to the control (P < 0.05). Metformin treatment at all levels altered the plasma profile of reproductive hormones, with significantly lower plasma testosterone concentrations and a decreased testosterone to androstenedione ratio in hens that received metformin (P < 0.05). In addition, a subset of chicks hatched (n= 50 chicks/treatment group/time point) was utilized to determine the effect of metformin on progeny performance. Broilers were reared according to the industry standards and were provided both feed and water ad libitum. Individual broilers were weighed weekly and total feed intake was recorded for the calculation of feed conversion ratios. Broilers were grown to day 42 at which they were processed for the collection of several data points including gender, live weight, bled weight, breast weight, thigh and drum weight, wing weight, body shell weight, fat pad weight, and total meat weight. Mortality rates among all four treatment groups did not differ significantly. We observed no significant effects of metformin on progeny performance across all time points. Future studies should focus on the mechanisms underlying the beneficial effects of metformin in increasing the fertile egg production of broiler breeder hens.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Weaver EA, Ramachandran R (2023) Metformin improves ovarian function and
increases egg production in broiler breeder hens. Reproduction, 165:289-300
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Elkin RG, El-Zenary ASA, Bomberger R, Haile AB, Weaver EA, Ramachandran R,
Harvatine KJ (2023) Feeding laying hens docosa hexaenoic acid-rich microalgae oil at
40 g/kg diet causes hypotriglyceridemia, depresses egg production, and attenuates
expression of key genes affecting hepatic triglyceride synthesis and secretion, but is
rescued by dietary co-supplementation of high-oleic sunflower oil. Poultry Science, 102:102318
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Van Syoc E, Weaver E, Rogers CJ, Silverman JD, Ramachandran R, Ganda E (2022)
Metformin modulates the gut microbiome in broiler breeder hens. Frontiers in Physiology, 13:1000144
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Anthony K, Garner TB, Ramachandran R, Diaz FJ (2022) Ad libitum feeding alters
mRNA abundance in the ovarian cortex of broiler breeder hens. Reproduction and Fertility, 3(2): 110-121
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Bai Y, Yuan P, Zhang H, Ramachandran R, Yang N, Song J (2020) Adiponectin and its
receptors genes expression in response to MDV infection of White Leghorns. Poultry Science, 99:4249-4258
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Hanlon C, Ramachandran R, Zuidhof MJ, Bedecarrats GY (2020). Should I lay or should I grow? Photoperiodic versus metabolic cues in chickens. Front Physiol. 11:707
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Hadley JA, Ocon-Grove OM, Ramachandran R (2020) Adiponectin is secreted by theca layer cells isolated from chicken ovarian follicles. Reproduction, 159:275-288
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Progress 05/15/21 to 05/14/22
Outputs
Target Audience:Scientists (faculty, graduate students, post-doctoral associates) in academia and poultry breeding companies are the target the audience for this research to improve the reproductive efficiency of broiler breeder chickens. Products Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A female undergraduate student (Everlyn Weaver) is being trained in our laboratory to conduct both basic and applied research related to commercial poultry production with the goal of improving reproductive efficiency in broiler breeder chickens. In addition, 4 undergraduate students are also being trained in our laboratory to conduct research. How have the results been disseminated to communities of interest?Through scientific publications What do you plan to do during the next reporting period to accomplish the goals?We will continue our research to determine if supplementing metformin to the diets of broiler breeder hens affects the transcriptomic profile in the liver, ovary, and adipose tissue.
Impacts
What was accomplished under these goals?
We have previously shown that feeding broiler breeder hens with a diet containing metformin significantly increase fertile egg production without affecting the hatchability of the eggs. In the following set of experiments, we sought to determine if metformin supplementation to the parent has any deleterious effect on the broiler progenies in terms of body growth and meta yield. Our objectives were to determine if metformin supplementation to the broiler breeder hen affects the livability, body weight, meat yield, and body fat in the broiler chicken progenies. Broiler breeder female (Cobb 500; Cobb-Vantress, Inc.) and male (Hubbard M99) chickens were housed individually in battery cages from 21 weeks of age and were feed-restricted according to the management guides. At 25 weeks of age, the broiler breeder hens were randomly allocated to four experimental groups (n=45 hens/treatment group) to receive four metformin levels (0, 25, 50 or 75 mg/kg body weight) supplemented in the diet. The metformin treatment continued until the end of the study, at which the chickens were 65 weeks of age. Male broiler breeders received no metformin supplementation in their diets. A subset of hens (n=20) from each treatment group were randomly selected for artificial insemination (AI). The same hens were utilized in all fertility and hatchability data collections which were conducted at ten different time points throughout the study (22, 25, 30, 35, 40, 45, 50, 55, 60 and 65 weeks of age). Eggs (n= 100 eggs/treatment group/time point) were candled on day 10 of incubation to determine fertility and hatchability were determined on day 21. No effect was observed on the fertility or hatchability of eggs among all treatment groups. A subset of chicks hatched (n= 50 chicks/treatment group/time point) was utilized to determine the effect of metformin on progeny performance. Broilers were reared according to the industry standards and were provided both feed and water ad libitum. Individual broilers were weighed weekly and total feed intake was recorded for the calculation of feed conversion ratios. Broilers were grown to day 42 at which they were processed for the collection of several data points including gender, live weight, bled weight, breast weight, thigh and drum weight, wing weight, body shell weight, fat pad weight and total meat weight. Mortality rates among all four treatment groups did not differ significantly. We observed no significant effects of metformin on progeny performance across all time points. Differences were observed between males and females which is expected. Although not significant, male broilers from hens supplemented at the highest dose (75 mg/kg metformin) tended to have a larger breast weight (735.72 grams vs. 683.28 grams), body shell weight (906.49 grams vs. 867.87 grams) and total meat weight (1679.74 grams vs. 1614.56 grams), on average, when compared to broilers from hens which received no metformin in the diet. Furthermore, male broilers from hens supplemented at all levels (25, 50 or 75 mg/kg body weight) tended to have smaller average fat pad weights when compared to broilers from hens that received no metformin in the diet. On the other hand, female broilers from hens supplemented at all levels (25, 50 or 75 mg/kg body weight) tended to have a lower average live weight (2.8 kg vs. 3.05 kg), bled weight (2.75 kg vs. 2.98 kg) and body shell weight (785 grams vs. 845 grams) when compared to female broilers from hens which received no metformin in the diet. However, when breast, thigh, and drum and wing weight were calculated as a percent of bled or live weight, females from hens that received metformin at all levels had a higher percentage for each when compared to females from the control group. This was also reflected in total meat weight as a percentage of live weight. Our results suggest that feeding broiler breeder hens with a diet containing metformin did not affect the broiler progenies while improving egg production.
Publications
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2022
Citation:
Van Syoc E, Weaver EA, Rogers C, Silverman J, Ramachandran R, Ganda E (2022) Metformin modulates the gut microbiome in broiler breeder hens. Frontiers in Physiology (acceptable pending revisions)
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2022
Citation:
Weaver EA and Ramachandran R (2022) Effect of dietary metformin supplementation on the reproductive efficiency of broiler breeder hens. Invited presentation at the International Symposium of Avian Endocrinology organized by University of Edinburgh, UK (July 2022)
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2022
Citation:
Weaver EA and Ramachandran (2022) Metformin Improves Ovarian Function and Increases Egg Production in Broiler Breeder Hens. Reproduction (acceptable pending revisions)
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Progress 05/15/20 to 05/14/21
Outputs
Target Audience:Scientists (faculty, graduate studetns, post-doctoral associates) in academia and poultry breeding companies are the target audience for this research to improve reproductive efficiency of broiler breeder chickens. Changes/Problems:The COVID pandemic significantly delayed our progress. However, we are taking every effort to succefully finish the project as origainally laid out with no or little modifications. What opportunities for training and professional development has the project provided?A female undergraduate student (Everlyn Weaver) is being trained in our laboratory to conduct both basic and appliedresearch related to commercial poultry production with a goal of improving reproductive efficiency in broiler breeder chickens. In addition, 4 undergraduate students are also being trained in our laboratory to conduct research. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?We will contine our research proposed in Aims 3 to determine if metformin affects fertility and hatachablility of eggs and to determine the performance of broiler chicken progenies upon hatching.
Impacts
What was accomplished under these goals?
The objectives of the following experiments were to determine if metformin supplementation to the broiler breeder hen feed affects i) body weight, ii) visceral adiposity, iii) ovarian follicular hierarchy, iv) total egg production, v) fertility and hatchability of eggs, and vi) plasma steroid hormone concentrations. A commercial strain of broiler breeder chickens (Cobb 500) was raised from one day of age until the end of the study (65 weeks). The chickens were reared according to the Cobb 500 Breeder Management Guideand photo-stimulated beginning at 21 weeks of age with a photoperiod of 16 h light:8h dark. At 24 weeks of age, the broiler breeder henswere randomly allocated to four experimental groups to receive 0, 25, 50, or 75 mg/kg body weight (BW) metformin mixed in a defined amount of feed. A subset of broiler breeder hens from each treatment group (n=10) was weighed every 10 weeks to adjust the amount of metformin mixed into the feed according to their change in weights over time. Blood samples were collected from the wing vein from a subset of hens (n=6/ treatment group) every 5 weeks for the quantification of plasma steroid hormone concentrations. Plasma was separated and stored at -80°C for analysis of plasma hormone concentrations. Plasma progesterone concentration was determined by a commercial human double antibody RIA kit. For the analysis of plasmatotal estrogens, testosterone, and androstenedione, an extraction step was carried out as recommended by the kit manufacturer. Hens receiving 75 mg metformin/kg BW had significantly lower body weights at 40-, 50-, 60- and 65 weeks of age when compared to the other treatment groups. In agreement with the observed decrease in body weight, hens receiving the highest dose of metformin had significantly smaller abdominal fat pads at the end of the study (65 weeks of age) compared to the control group and the group receiving the lowest dose of metformin (25 mg/kg BW. The hyper-recruitment of preovulatory and prehierarchical follicles is commonly observed in the broiler breeder hen. However, supplementation of metformin in the diet, even at the lowest dose (25 mg/kg BW) was found to normalize the ovarian follicular hierarchy with an appropriate number of preovulatory and prehierarchical follicles. The supplementation of metformin into the diet of broiler breeder hens increased the total number of eggs laid for the entire production period in each treatment group (25, 50, or 75 mg/kg body weight) when compared to the control with no effect on fertility and hatchability of the eggs. Metformin supplementation was found to significantly decrease plasma progesterone and total estrogen concentrations. The hens which received no metformin in their diet had significantly greater plasma progesterone concentrations at 35, 40, and 45 weeks of age when compared to the hens which received 50 or 75 mg metformin/kg body weight. A similar trend was observed in plasma total estrogen concentrations in which hens that received no metformin in their diet had significantly greater plasma estrogen concentrations at 35, 40, 45, 50, and 60 weeks of age when compared to the groups which received metformin. At 60 weeks of age, all groups which received metformin (25, 50, or 75 mg/kg body weight) had significantly greater plasma progesterone concentrations when compared to the control group. At 30 weeks of age, metformin significantly lesser plasma testosterone concentrations when treated with 75 mg/kg BW when compared to the control. There was no effect of metformin on plasma testosterone concentrations from 35-55 weeks of age. However, hens that received no metformin in the diet had significantly higher plasma testosterone concentrations at 60 and 65 weeks of age when compared to hens that received any amount of metformin in the diet. There was no effect of metforminon plasma androstenedione concentrations across all time points. In summary, dietary supplementation of metformin increased overall fertile egg production from broiler breeder hens. The ovarian morphology and the changes observed in the reproductive hormone profile in response to metformin supplementation underlie the improved reproductive efficiency of broiler breeder hens.
Publications
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Progress 05/15/19 to 05/14/20
Outputs
Target Audience:Scientists (faculty, graduate studetns, post-doctoral associates) in academia and poultry breeding companies are the target audience for this research to improve reproductive efficiency of broiler breeder chickens. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A female undergraduate student (Everlyn Weaver) is being trained in our laboratory to conduct both basic and appliedresearch related to commercial poultry production with a goal of improving reproductive efficiency in broiler breeder chickens. In addition, 4 undergraduate students are also being trained in our laboratory to conduct research. How have the results been disseminated to communities of interest?Through scientific publication. What do you plan to do during the next reporting period to accomplish the goals?We will contine our research proposed in Aims 2 and 3 to determine if metformin affects fertility and hatachablility of eggs and to determine the performance of broiler chicken progenies upon hatching.
Impacts
What was accomplished under these goals?
One of the aims was to determine if treatment of granulosa cells isolated from broiler breeder hen ovarian follicle with metformin affects critical signal transduction events, expression of genes related to steroidogenesis, and progesterone secretion. Commercial broiler breeder hens were raised according to the COBB Breeder Management Guidelines. Hens (35-45 weeks old) were euthanized to collect the ovary. Ovarian follicles were grouped by stage of maturation into prehierarchical follicles (3-5 and 6-8 mm) and preovulatory follicles (9-12 mm and F5/6). The granulosa cell layer from each follicle was collected and pooled from 4 hens to form one biological replicate. Granulosa cells were treated with recombinant human follicle-stimulating hormone (rhFSH) and metformin (0, 1, 10, or 20 mM) for 15 minutes to 3 hours. Total protein was collected to determine the abundance of phospho-adenosine monophosphate-activated protein kinase (pAMPK) and phospho-acetyl coenzyme-A (pACC) using Western blot analysis. Total RNA from granulosa cells was extracted and subjected to real-time quantitative PCR (qPCR) analysis for quantification of messenger ribonucleic acid encoding follicle stimulating hormone receptor (FSHR), steroidogenic acute regulatory protein (STAR), cholesterol side-chain cleaving enzyme (CYP11A1), and 3-beta hydroxysteroid dehydrogenase (HSD3B1) abundance. Progesterone concentrations in culture media following metformin treatment were quantified by enzyme-linked immunosorbent assay. We found that metformin treatment did not affect the abundance of pAMPK and pACC in granulosa cells isolated all follicle categories. However, treatment of granulosa cells isolated from prehierarchical follicles (3-5 and 6-8 mm) and the most-recently recruited preovulatory follicle (9-12 mm) with metformin significantly decreased the abundance of FSHR mRNA. We observed a lesser abundance of STAR mRNA in granulosa cells isolated from 6-8 mm and 9-12 mm follicles when treated with metformin at 10 or 20 mM compared to 0 or 1 mM metformin treatment. etformin treatment resulted in a significantly lesser abundance of STAR mRNA in 3-5 mm follicular granulosa cells when compared to the cells that received no metformin and were only stimulated with rhFSH. In the same cell population, the abundance of CYP11A1 mRNA was lesser in response to 20 mM metformin treatment compared to 0 mM level. In 6-8 mm follicular granulosa cells, a dose-dependent decrease in CYP11A1 abundance was observed when treated with metformin. In 9-12 mm follicular granulosa cells, metformin treatment resulted in a lesser abundance of CYP11A1 mRNA compared to the cells that received no metformin treatment and were only stimulated with rhFSH. While metformin treatment had no effect on the abundance of HSD3B1 mRNA in 3-5 mm follicular granulosa cells, a dose of 10, or 20 mM metformin treatment resulted in a lesser abundance of HSD3B1 mRNA in 6-8 mm granulosa cells compared to 0 and 1 mM metformin treatment. A dose-dependent decrease in the abundance of HSD3B1 mRNA in 9-12 mm follicular granulosa cells was observed in response to 0, 1, 10, or 20 mM metformin treatment. Treatment of granulosa cells isolated from 6-8 mm prehierarchical follicle with 10 or 20 mM metformin resulted in a decrease in progesterone concentrations back to the levels observed with the control at 72 h of treatment, but not at 24 and 48 h. A dose-dependent decrease in progesterone concentration was observed when granulosa cells isolated from the most recently recruited preovulatory follicle were treated with metformin for 24, 48, or 72 h with 20 mM of metformin having the most-significant effect. Similar to 9-12 mm follicular granulosa cells, treatment of the smallest preovulatory follicle (F5) granulosa cells with metformin decreased progesterone concentrations in a dose-dependent manner at 24, 48 and 72 h of culture with 10 and 20 mM of metformin having the most-significant effect. In summary, the expression of genes related to steroidogenesis such as FSHR, STAR, CYP11A1, HSD3B, and progesterone secretion was significantly decreased in response to metformin treatment in a dose-dependent manner. Our data suggest that metformin treatment attenuates progesterone secretion via AMPK-independent pathways in granulosa cells of prehierarchical and preovulatory follicles of broiler breeder hens. We are currently investigating if metformin administration could ameliorate ovarian dysfunction and increase egg production in obese broiler breeder hens.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Weaver EA and Ramachandran R (2020) Metformin Attenuates Steroidogenesis in Ovarian Follicles of the Broiler Breeder Hen. Reproduction (In print)
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Progress 05/15/18 to 05/14/19
Outputs
Target Audience:Scientists in academic instituitions and in commercial broiler chicken parent breeder farms Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A female undergraduate student (Everlyn Weaver) is being trained in our laboratory to conduct both basic and applied research related to commercial poultry production with a goal of improving reproductive efficiency in broiler breeder chickens. Ms. Weaver won a Certificate of Excellence for her platform presentation of the data reported in this report at the annual meeting of the Poutlry Science Association. Furthermore, 3-5 undergraduate students are also being trained in our laboratory to conduct research. How have the results been disseminated to communities of interest?Through publicagtion of an abstract that was presented at the annual meeting of the Poutry Science Association in July 2019. What do you plan to do during the next reporting period to accomplish the goals?We will contine our research proposed in Aims 2 and 3 to determine if metformin affects fertility and hatachablility of eggs and determine the performance of broiler chicken progenies upon hatching.
Impacts
What was accomplished under these goals?
Commercial broiler breeder hens were raised according to the COBB Breeder Management Guidelines. Ovaries were harvested from hens around 35 weeks of age (n=46) and individual follicles were separated for granulosa cell extraction. Our goal was to determine the effect of metformin on signaling pathways involved in cell proliferation and cell metabolism in granulosa cells. We first focused on activation of extracelluar signal regulated kinase (ERK) and protein kinase B (AKT) pathways, both are involved in cell proliferation and cell survival In addition, activation of ERK is also known to have an inhibitory effect on FSH-sensitivity in granulosa cells. We first studied the most recently recruited (9-12 mm) ovarian follicle which begin to differentiate and become responsive to FSH upon recruitment into the preovulatory pool. Granulosa cells collected from 9-12 mm follicles were treated with metformin (0, 1, 10 or 20 mM). for 15 min - 4 hours. A cell lysate was prepared and subjected to Western blot analysis to quantify the level of key signaling molecules. We observed a dose-dependent decrease in the phosphorylation of ERK with 20 mM of metformin having the most significant effect (p < 0.001). Similarly, we observed dose-dependent decrease in the phosphorylation of AKT with 10 and 20 mM having the most significant effect (p < 0.001). Based on these findings we concluded that at lower doses of metformin (1 mM), inhibition of phospho-ERK on FSH-sensitivity is relieved and the granulosa cells can maintain differentiation and proliferation in response to FSH. On the other hand, when treated with the highest dose, the decrease in the phosphorylation of both ERK and AKT may be indicative of a significant decrease in cell proliferation and possibly the downstream activation of pathways involved in apoptosis. We then focused on undifferentiated granulosa cells present in 6-8 mm prehierarchal follicles which provide the pool from which the next preovulatory follicle will be recruited from. When treated with metformin, the lowest dose (1 mM) maintained the level of phosphorylation of ERK while the highest doses (10 and 20 mM) significantly decreased the abundance of phospho-ERK in a dose-dependent manner (p < 0.001). Similarly, phosphorylation of AKT was decreased in a dose-dependent manner, with 10 and 20 mM having the most significant effect (p < 0.001). Based on these findings, we conclude that treatment with the lowest dose of metformin (1 mM) maintains granulosa cells in an undifferentiated state and inhibits premature FSH-sensitivity. Furthermore, higher doses of metformin may be leading to a decrease in cell proliferation and possible induction of downstream apoptotic pathways, therefore decreasing the hyper-recruitment of prehierarchal follicles. Our findings on these two key signaling pathways may explain the molecular basis for the increased egg production obtained from broiler breeder hens fed with a diet containing metformin.
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2019
Citation:
*Weaver EA, Diaz FJ, Johnson AL and Ramachandran R (2019) Metformin Alters Granulosa Cell FSH-Responsiveness in Preovulatory and Prehierarchal Follicles in Broiler Breeder Hens. Proceedings of the Annual meeting of the Poultry Science Association held in July 2019 at Montreal, Canada. * gradute student presenter awarded Certificate of Excellence for her platform presentaion.
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Progress 05/15/17 to 05/14/18
Outputs
Target Audience:Scientists in academic institutions and in commercial broiler chicken breeder farms. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A female graduate student (Evelyn Weaver) is being trained in our laboaratory to conduct scientific research with the goal of improving reproductive efficiency in broiler breeder chickens. I addition, three undergraduate students were also tranined during the Spring semester to maintain and mangae commercial broiler breeder hens. How have the results been disseminated to communities of interest?Through publication of an abstract that will be presented at the Annual meeting of the Society for the Study of Reproduction in July. What do you plan to do during the next reporting period to accomplish the goals?We are planning to continue our research on understading how folliculogenesis can be controlled to improve egg production in commercial broiler breeder hns.
Impacts
What was accomplished under these goals?
To gain a better understanding on the role metformin plays in the modification of gene expression related to folliculogenesis in follicular granulosa cells, we stimulated granulosa cells with recombinant human follicle stimulating hormone (rhFSH) and then treated them with 1millimolar (mM), 10 mM or 20 mM of metformin. We used qPCR to quantify known factors involved in folliculogenesis in Cobb 500 broiler breeder hens around 40 weeks of age (n=12). The birds were fed a restricted diet according to the COBB breeder management guide. Granulosa cells collected from individual pre-hierarchal follicles were grouped by follicle diameter (3-5mm, 6-8mm and 9-12mm) and were pooled from four individual birds to form one biological replicate, with a total of three biological replicates used for quantitative polymerase chain reaction (qPCR) analysis (n=3). Gene transcripts analyzed included follicle stimulating hormone receptor (FSHR), vasoactive intestinal polypeptide receptor (VIPR1), steroid-acute regulatory protein (STAR), cholesterol side-chain cleaving enzyme (CYP11A1) and 3beta-hydroxysteroid dehydrogenase (HSD3B). In 9-12mm follicles, granulosa cells expressed significantly higher levels of FSHR, VIPR1, STAR, CYP11A1 and HSD3B messegen ribonucleic acid (mRNA) when challenged with rhFSH (P<0.01). Among the metformin treatments, 20 mM of metformin had the greatest effect on gene expression among the transcripts analyzed in 9-12mm follicles. The addition of 20 mM of metformin significantly decreased the levels of FSHR, VIPR1, STAR, CYP11A1 and HSD3B mRNA (P<0.01). In 6-8 mm and 3-5 mm follicles, granulosa cells expressed significantly higher levels of FSHR and STAR mRNA when challenged with rhFSH (P<0.01). In the 6-8 mm granulosa cell population, STAR, CYP11A1 and HSD3B mRNA were significantly decreased in a dose dependent manner, with 20 mM of metformin having the most significant effect (P<0.001). Results obtained thus far suggest that metformin has an inhibitory effect on granulosa cell steroidogenesis and responsiveness to follicle stimulating hormone.
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2018
Citation:
Weaver E, Diaz FD, Johnson AL, Ramachandran R. Expression of genes related to steroidogenesis in the broiler breeder hen ovary
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