title: Molecular ontogenesis of digestive capability and associated endocrine control in Atlantic cod (Gadus morhua) larvae.
abstract: We have profiled the expression of twelve genes, in order to provide an overview on the molecular ontogeny of digestive capability with the associated endocrine control during Atlantic cod (Gadus morhua) larval development. Enzyme activity levels for the key digestive enzyme, trypsin, was also measured. Specifically, transcripts for trypsin, amylase, lipolytic enzymes: bile salt activated lipase (BAL), phospholipase A2 (PLA2) and Acyl CoA dehydrogenase (ACADM), regulatory peptides: neuropeptide Y (NPY), orexin (OX) cholecystokinin (CCK) and cocaine and amphetamine-related transcript (CART), the somatotropic factors: growth hormone (GH), preprosomatostatin 1 (PPSS1) and thyroid hormone receptors (TRα and TRβ) were analyzed using quatitative (real-time) polymerase chain reaction (qPCR). Trypsin and BAL mRNA levels peaked at approximately day 17 and 25 post-hatch, respectively, and thereafter displayed a decreasing pattern until metamorphosis. GH mRNA levels decreased moderately from 3 to 33dph, and thereafter, an increase was observed until 46dph. TRα mRNA levels showed a fluctuating pattern peaking at day 39 post-hatch. TRβ mRNA levels were too low to obtain quantitative measurements. Amylase mRNA slightly increased from day 3 to 17 post-hatch, and thereafter showed a steady decrease until day 60. Interestingly, PLA2 mRNA expression showed a consistent increase throughout the study period, indicating an increasingly important role during larval development. Overall, data from this study indicate that cod larvae show differential developmental mode of expression patterns for key genes and endocrine factors that regulate digestive capability, growth and development. These data are discussed in relation to larval trypsin enzyme activity and previous reports for other teleost species.
authors.affiliation: Department of Biology, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway.
authors.forename: Trond M
authors.initials: TM
authors.lastname: Kortner
authors.forename: Ingrid
authors.initials: I
authors.lastname: Overrein
authors.forename: Gunvor
authors.initials: G
authors.lastname: Oie
authors.forename: Elin
authors.initials: E
authors.lastname: Kjørsvik
authors.forename: Tora
authors.initials: T
authors.lastname: Bardal
authors.forename: Per-Arvid
authors.initials: PA
authors.lastname: Wold
authors.forename: Augustine
authors.initials: A
authors.lastname: Arukwe
mesh_terms: D000681:Amylases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001069:Appetite Regulation / Q000235:genetics; D004063:Digestion / Q000235:genetics*; D004064:Digestive System / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism; D057075:Enzyme Assays; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism; D048389:Gadus morhua / Q000235:genetics / Q000254:growth & development*; D005768:Gastrointestinal Hormones / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D000068797:Orexins; D013004:Somatostatin / Q000235:genetics / Q000378:metabolism; D014357:Trypsin / Q000235:genetics / Q000378:metabolism; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
chemical_list: D029941:Fish Proteins; D005768:Gastrointestinal Hormones; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y; D009479:Neuropeptides; D000068797:Orexins; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein; D013004:Somatostatin; D000681:Amylases; D014357:Trypsin