Research interests

Major area of research


Neuroendocrine mechanisms regulating food intake and reproductive behavior in fish

Overview of hormones, feeding and reproduction

In vertebrates, growth and reproduction require a tight regulation of energy balance, the net difference between energy intake and expenditure. In mammals, the regulation of food intake involves hormones produced by both brain and peripheral tissues. These hormones either stimulate (orexigenic) or inhibit (anorexigenic) feeding. Among brain factors are the orexigenic neuropeptide Y (NPY) and orexins (OX), and the anorexigenic CART (cocaine and amphetamine regulated transcript). Peripheral feeding regulators include gut hormones, such as cholecystokinin (CCK) and gastrin-releasing peptide (GRP), the pancreatic hormone amylin, and the stomach-derived hormone ghrelin.

To date, most of our knowledge on the endocrine regulation of feeding comes from mammalian studies. Although homologs of mammalian feeding-related peptides have been identified in fish and shown to regulate feeding via mechanisms apparently similar to that seen in mammals, our current understanding of the regulation of feeding in fish is very limited. Very few marine species have been examined.

Several factors appear to affect appetite in vertebrates. These include internal factors, such as nutrional status (eg. fasting) and a variety of external factors - including temperature, photoperiod and environmental contaminants. Reproductive function and food intake are also closely linked as successful reproduction depends on adequate reserves of metabolic fuels. Our understanding of the physiological mechanisms underlying these relationships is far from clear.
Why fish?

Fish are capable of undergoing prolonged periods of fasting. The endocrine mechanisms controlling such drastic changes in feeding behavior have never been investigated.



In fish, seasonal changes in feeding behavior often coincide with spawning migration and reproduction.





Assessing the role of appetite regulators in the reproductive cycle of fish could provide important clues to understand the link between nutrition and the reproductive axis.


Our research objectives and approaches

We use goldfish and several marine fish (Atlantic cod, flounder...) as models for our studies

Objective Approach and techniques
identify hormones involved in feeding in fish gene and cDNA cloning
localize sites of production RT-PCR, Northern/slot blots of tissues
assess the effects of intrinsic/extrinsic factors on the action/expression of hormones gene expression studies (quantitative PCR)
assess the effects of reproductive stages on the action/expression of hormones gene expression studies (quantitative PCR)
assess the effects of hormones on feeding Behavioral observations and assessment of food intake following in vivo brain and peripheral (intraperitoneal) injections of hormones
assess the effects of hormones on reproductive behavior Behavioral observations and assessment of food intake following in vivo brain and peripheral injections of hormones

These studies will help us

  • establish a model of the endocrine regulation of feeding in vertebrates
  • provide new approaches to manage and enhance growth and reproduction in fish (critical for the aquaculture industry).
  • produce important new insights into the mechanisms that rule diseases involving dysregulation of energy homeostasis in mammals, e.g. obesity and diabetes (medical applications)