title: Appetite regulating factors in pacu (Piaractus mesopotamicus): Tissue distribution and effects of food quantity and quality on gene expression.
abstract: The pacu Piaractus mesopotamicus is an omnivorous fish considered a promising species for aquaculture. Little is known about the endocrine regulation of feeding in this species. In this study, transcripts for orexin, cocaine and amphetamine regulated transcript (CART), cholecystokinin (CCK) and leptin were isolated in pacu. Orexin, CCK and leptin have widespread mRNA distributions in brain and periphery, CART is limited to the brain. To examine the role of these peptides in the regulation of feeding and energy status, mRNA expression levels were compared between fed and fasted fish and around feeding time. Both orexin and CART brain expressions were affected by fasting and displayed periprandial changes, suggesting a role in both short- and long-term regulation of feeding. CCK intestinal expression decreased in fasted fish and displayed periprandial changes, suggesting CCK acts as a peripheral satiety factor. Leptin was not affected by fasting but displayed periprandial changes, suggesting a role as a short-term regulator. To examine if these peptides are affected by diet, brain and gut expressions were assessed in fish fed with different diets containing soy protein concentrate. Food intake, weight gain and expressions of orexin, CART, CCK and leptin were little affected by replacement of fish protein with soy protein, suggesting that pacu is able to tolerate and grow well with a diet rich in plant material. Overall, our results suggest that orexin, CART, CCK and leptin are involved in the physiology of feeding of pacu and that their expressions are little affected by plant-based diets.
authors.affiliation: Department of Biology, Memorial University of Newfoundland, St. John's, NL A1B3X9, Canada; Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL A1B3X9, Canada. Electronic address: hvolkoff@mun.ca.
authors.forename: Hélène
authors.initials: H
authors.lastname: Volkoff
authors.affiliation: Departamento de Zootecnia, Setor de Piscicultura, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, 13418-900 Piracicaba, SP, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Estevan Sabioni
authors.affiliation: Departamento de Zootecnia, Laboratório de Biotecnologia Animal, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, 13418-900 Piracicaba, SP, Brazil.
authors.forename: Luiz Lehmann
authors.initials: LL
authors.lastname: Coutinho
authors.affiliation: Departamento de Zootecnia, Setor de Piscicultura, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, 13418-900 Piracicaba, SP, Brazil.
authors.forename: José Eurico Possebon
authors.initials: JE
authors.lastname: Cyrino
mesh_terms: D000821:Animal Feed; D000818:Animals; D001069:Appetite Regulation; D017756:Aquaculture; D001921:Brain / Q000254:growth & development / Q000378:metabolism; D002766:Cholecystokinin / Q000235:genetics / Q000378:metabolism; D004032:Diet / Q000009:adverse effects / Q000662:veterinary*; D002149:Energy Intake; D029941:Fish Proteins / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism*; D005399:Fishes / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D007413:Intestinal Mucosa / Q000378:metabolism; D020738:Leptin / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D000068797:Orexins / Q000235:genetics / Q000378:metabolism; D009928:Organ Specificity; D011897:Random Allocation; D030262:Soybean Proteins / Q000008:administration & dosage; D015430:Weight Gain; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
chemical_list: D029941:Fish Proteins; D020738:Leptin; D009419:Nerve Tissue Proteins; D000068797:Orexins; D030262:Soybean Proteins; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein; D002766:Cholecystokinin
keywords: Expression; Fasting; Feeding; Hormone; Pacu; Plant-based diets; Soy protein concentrate