2025.11.10
RESEARCH NEWS STORY
Understanding Leptin in Birds: New Insights in Poultry Science
Researchers explore the role of leptin in birds’ reproduction, with mammalian comparisons, aiding in optimization of sustainable poultry production
Leptin is an anorexigenic hormone that plays a vital role in reproductive physiology and nutrient intake, with the secreting source being different in mammals and birds. Despite its significant influence on reproduction and food intake, the mechanisms of leptin’s actions are not yet fully understood. Researchers have begun investigating these pathways to better understand its role during different life stages of birds. Their findings are critical for the optimization of sustainable meat and egg production.
Image title: Role of Leptin in Female Reproduction in Birds and Mammals
Image caption: Researchers review the role of leptin in female reproduction in birds while comparing the different developmental stages to mammals
Image credit: Dr. Sadequllah Ahmadi from Ibaraki University, Japan
License type: Original content
Usage restrictions: Cannot be used without permission
Leptin is an anorexigenic hormone that plays a key role in regulating food intake, ovarian development, and reproduction in mammals. However, its physiological role in birds remains less understood, compared to mammals. A significant knowledge gap exists between leptin levels and reproductive processes in layer and broiler parent stock chickens. A deeper understanding of these mechanisms could aid in optimizing sustainable global meat and egg production, particularly in challenging conditions like nutrient-deficient environments, where the reproductive efficiency may be compromised.
Against this backdrop, Dr. Sadequllah Ahmadi and Dr. Takeshi Ohkubo from the College of Agriculture, Ibaraki University, Japan, conducted a comprehensive review of leptin’s influence on female reproduction in birds, focusing on early folliculogenesis and ovarian development, and compared these mechanisms with those observed in mammals. This review was published in Volume 62 of The Journal of Poultry Science on February 06, 2025.
“In mammals, leptin is secreted by the adipocytes and its role has been clearly elucidated. However, in birds, leptin is primarily expressed in the brain and gonads with its mechanisms being unclear. A deeper understanding of leptin’s role in reproduction could help improve reproductive efficiency and sustainability in poultry production,” says Dr. Ahmadi, as the motivation behind the study.
In mammals, leptin is secreted primarily by adipose tissue, which then circulates in the blood stream, signaling energy sufficiency to the brain and regulating the secretion of reproductive hormones like luteinizing hormone and follicle-stimulating hormone. On the other hand, in birds, leptin is expressed locally in the brain, especially in the pituitary glands and gonads, and not secreted by adipocytes.
Delving into the mechanism of action, leptin binds to LEPR, the leptin receptor, and activates several vital cellular signaling pathways, including JAK/STAT, MAPK, and PI3K-AKT, which activate follicle growth, hormone production, and ovarian development. Dr. Ahmadi notes, “The signaling pathways activated by leptin through its receptor play an important role in cellular processes that are essential for reproductive function.”
Leptin regulates reproductive processes at different developmental stages. During embryonic development, leptin enhances embryonic muscle cell proliferation, supports nutrient transport, and oocyte maturation. In juvenile birds, leptin enhances the formation of primordial follicles by regulating ovarian growth factors such as inducing insulin-like growth factor 1 and reducing anti-Müllerian hormone expression. These mechanisms prepare the ovary for future follicle recruitment and maturation. While in adult birds, leptin promotes embryonic growth and angiogenesis, while stimulating pituitary hormones that are involved in reproduction.
In adult birds, leptin plays a crucial role in maintaining ovarian function and egg production, especially during nutrient-deficient conditions. It supports hormone synthesis and protects follicular development when energy intake is low. “Leptin helps maintain ovarian function and egg production even during times of limited feed availability. This finding indicates that leptin could be used as a potential biomarker for egg production,” says Dr. Ahmadi.
Interestingly, the effects of leptin also vary between bird types. “In layer-type birds, it improves the egg-laying performance by enhancing follicular activation and steroid hormone production, while in broiler birds, excessive leptin activity may even accelerate early follicular growth and premature depletion of follicle pool,” explains Dr. Ahmadi. He adds, “Understanding these differences could help refine breeding strategies based on bird type.”
This review provides new insights into leptin’s role in birds and its potential use as a biomarker for reproductive performance. Overall, this study advances the understanding of avian physiology and also offers practical implications for improving meat and egg production in a sustainable way.
Reference
| Title of original paper: | A Bird’s-Eye Overview of Leptin and Female Reproduction —with Mammalian Comparisons |
|---|---|
| Authors | Sadequllah Ahmadi1, 2 and Takeshi Ohkubo1 |
| Affiliations | 1 College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Ibaraki 300-0393, Japan 2Faculty of Animal Science, Afghanistan National Agricultural Sciences and Technology University (ANASTU), Kandahar 3801, Afghanistan |
| Journal: | The Journal of Poultry Science |
| DOI | https://doi.org/10.2141/jpsa.2025007 |
Additional information for EurekAlert
| Latest Article Publication Date: | 06 February 2025 |
|---|---|
| Subject of Research: | Literature review |
| Subject of Research: | Animals |
| Conflicts of Interest Statement: | The authors declare no conflicts of interest. |
About Ibaraki University, Japan
Ibaraki University, located in National Capital Region comprises five colleges of Humanities and Social Sciences, Education, Science, Engineering, and Agriculture. The university has been surrounded by various agriculture- and manufacturing-based industries and has been effectively contributing to the fields of quantum beam science and adaptation science for climate change. With the educational goals of nurturing students to respond proactively in the 21st century and to forge their own paths to the future, the university strives to improve academic skills by engaging in different educational activities.
Website: https://www.ibaraki.ac.jp/en/education/agriculture/
About Dr. Sadequllah Ahmadi from Ibaraki University, Japan
Dr. Sadequllah Ahmadi is a visiting scholar and a postdoctoral research fellow at the College of Agriculture, Ibaraki University, Japan, specializing in reproductive physiology. He received his doctoral degree in Reproductive Physiology from the Tokyo University of Agriculture and Technology, Japan. His research focuses on the hormonal and nutritional factors influencing gonadal growth, specifically the proliferation of granulosa cells and oocytes, as well as folliculogenesis, with implications for enhancing poultry productivity. He has published seven articles, with more than 30 citations.
Funding information
This study was supported by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grant number 23KF0009).
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Kazuhisa Honda
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