Feedback from Arctic charr: Feed flavour stimulation and re-feeding after feed deprivation stimulate genes encoding both orexigenic and anorexigenic neuropeptides

Striberny, Anja; Jørgensen, Even H.

doi:10.1016/j.ygcen.2017.03.012

Cited by 7 publications

(8 citation statements)

References 41 publications

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“…As such, based on the brain transcriptome, no hunger signalling by up-regulation of NPY could be found in the FDP fish. This finding is in accordance with the lack of responses seen in other feed deprivation studies with in Atlantic cod [49], Atlantic salmon [48], charr [19] and rainbow trout [46].…”

Section: Discussionsupporting

confidence: 92%

“…If CART exhibits an anorexigenic function in charr, the lower expression of CART in both fed and FDP fish over time points towards a seasonal increase in hunger signalling in both treatment groups, but no response to feed deprivation. This corresponds to the lack of responses in hypothalamic CART expression seen in previous long-term feed deprivation studies with rainbow trout (4 months) and Arctic charr (4 weeks) [19, 46]. In contrast, brain CART expression decreased in zebrafish after 3 days feed deprivation [47], in Atlantic salmon after 6 days of feed deprivation [48] and in Atlantic cod ( Gadus morhua ) after 7 days feed deprivation [49].…”

Section: Discussionsupporting

confidence: 64%

“…This result does not necessarily contradict an appetite regulatory role of these actors in this fish. In a previous study with charr, no differences in the hypothalamic expression of AgRP , MC4R , CRF , NPY , CART , POMC s and LEPR were seen between fed and 4 weeks feed deprived fish, whereas the expression of, CART , MC4R and AgRP changed in feed deprived upon re-feeding or exposure to feed flavour for 1 or 5 h [19]. This indicates that changes in gene expression are more likely to be seen during transition stages than during steady-state situations.…”

Section: Discussionmentioning

confidence: 93%

“…Putatively anorexigenic corticotrophin releasing factor ( CRF ) expression was lower in FDP charr at T 1 than at T 0 (LogFC − 0.55). Previously, reduced CRF brain expression levels were observed in goldfish ( Carassius auratus ) after 7 days of feed deprivation [51] whereas no changes were observed after short (7 days)- and long-term (4 weeks) feed deprivation in charr [19] or after long-term feed deprivation in rainbow trout [46].…”

Section: Discussionmentioning

confidence: 99%

“…Despite such seasonal changes in food intake, the expressions of orexigenic and anorexigenic appetite regulators in different brain regions is similar between anorexic winter charr with hyperphagic summer charr [18]. Furthermore, the expressions of orexigenic and anorexigenic neuropeptides in the hypothalamus are unaffected by short- and long-term feed deprivation in this species [19]. However, in these and in most other studies investigating appetite regulation in fish, expression levels of known appetite regulators have been measured by RT-qPCR, a method with the drawback of restricting the focus to a limited number of genes.…”

Section: Introductionmentioning

confidence: 99%

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Arctic charr brain transcriptome strongly affected by summer seasonal growth but only subtly by feed deprivation

Striberny

Jørgensen

Klopp³

et al. 2019

BMC Genomics

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Background The Arctic charr ( Salvelinus alpinus ) has a highly seasonal feeding cycle that comprises long periods of voluntary fasting and a short but intense feeding period during summer. Therefore, the charr represents an interesting species for studying appetite-regulating mechanisms in fish. Results In this study, we compared the brain transcriptomes of fed and feed deprived charr over a 4 weeks trial during their summer feeding season. Despite prominent differences in body condition between fed and feed deprived charr at the end of the trial, feed deprivation affected the brain transcriptome only slightly. In contrast, the transcriptome differed markedly over time in both fed and feed deprived charr, indicating strong shifts in basic cell metabolic processes possibly due to season, growth, temperature, or combinations thereof. The GO enrichment analysis revealed that many biological processes appeared to change in the same direction in both fed and feed deprived fish. In the feed deprived charr processes linked to oxygen transport and apoptosis were down- and up-regulated, respectively. Known genes encoding for appetite regulators did not respond to feed deprivation. Gene expression of Deiodinase 2 ( DIO2 ), an enzyme implicated in the regulation of seasonal processes in mammals, was lower in response to season and feed deprivation. We further found a higher expression of VGF (non-acronymic) in the feed deprived than in the fed fish. This gene encodes for a neuropeptide associated with the control of energy metabolism in mammals, and has not been studied in relation to regulation of appetite and energy homeostasis in fish. Conclusions In the Arctic charr, external and endogenous seasonal factors for example the increase in temperature and their circannual growth cycle, respectively, evoke much stronger responses in the brain than 4 weeks feed deprivation. The absence of a central hunger response in feed deprived charr give support for a strong resilience to the lack of food in this high Arctic species. DIO2 and VGF may play a role in the regulation of energy homeostasis and need to be further studied in seasonal fish. Electronic supplementary material The online version of this article (10.1186/s12864-019-5874-z) contains supplementary material, which is available to authorized users.

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