What hormones may regulate food intake in fish?

Abstract

This is an ovcmicw of thc hormoncs which may be involved in food intake control in fish, and some hypothetical pathways of thcir action arc givcn based on mammalian knowledge. Most of the observed effects of these hormones may result from four types of mechanisms, each hormone acting by one or several as follows: (1) hormones could have a direct effect on central nervous system centres, associated with food intake behaviour or via vagal afferent neurons; (2) an indirect effect may occur via the gut which slows gastrointestinal transit, thus rcsulting in stomach distention which activates vagal afferent neurons; (3) they could have an indirect cffcct, acting dircctly on intermediary metabolism via glucose, free fatty acids or amino acids mohilization or storage; (4) the last possible pathway is an indirect effect by modifying directly or indirectly secretions of other hormones involved in food intake control. Some of thesc hormones (CCK, PYY, glucagon, adrenalin) act as short-term factors which regulate meal ingestion and are generally inhibitory factors. On thc othcr hand, other hormones (GH, TH, and leptin) require more time to modify food intake behaviour, and appcar as stored calorie rcgulators. However, the orientation of hormones to short-terin or to long-term action is not always clear as it has been noted for insulin and glucocorticoids, and may depend on the hormonal and metabolite environment.

Effects of Enteromyxum scophthalmi experimental infection on the neuroendocrine system of turbot, Scophthalmus maximus (L.)

“…GLUC is a peptide with hyperglycaemic and lipolytic action in fish [29]. Its levels appear increased after feeding [30], fact related to higher plasma levels of glucose and stimulation of inhibitory feeding systems, which results in an anorexigenic effect in fish [31]. The distribution of GLUC-immunoreactive cells observed in this work was similar to that described by Reinecke et al [32] in juvenile turbot.…”

Relation between dietary lipid level and voluntary feed intake, growth, nutrient gain, lipid deposition and hepatic lipogenesis in rainbow trout

“…A recent study with European sea bass [34] showed that the dietary dilution with bulk agents increases VFI, but when corrected for nutrient dilution, VFI expressed per unit of body weight remains constant. It cannot therefore be excluded that regulation of food intake, when animals are fed with diets of extremely low or extremely high energy density, may be partially mediated through the control of gastric emptying [62].…”

Role of glass eel salinity preference in the control of habitat selection and growth plasticity in Anguilla anguilla

“…We also noticed that the intense feeding activity in SW promoted cannibalism, a well-known phenomenon in eel culture (Degani & Levanon 1983). In teleosts, hypo-osmoregulation has been shown to enhance secretion of GH, which promotes growth, appetite and aggressive behavior (Le Bail & Boeuf 1997, Jönsson et al 1998, Boeuf & Payan 2001. There-fore, we suggest that the stimulatory effects of salinity on glass eel growth may result from various effects on metabolism, appetite, feeding and aggressive behaviors, some of them being possibly mediated by increased GH secretion.…”