Blar i Bergen Open Research Archive på forfatter "Rønnestad, Ivar"
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Functional characterization of Atlantic salmon (Salmo salar L.) PepT2 transporters
Vacca, Francesca; Gomes, Ana S.; Murashita, Koji; Cinquetti, Raffella; Roseti, Cristina; Barca, Amilcare; Rønnestad, Ivar; Verri, Tiziano; Bossi, Elena (Journal article; Peer reviewed, 2022)The high-affinity/low-capacity system Slc15a2 (PepT2) is responsible for the reuptake of di/tripeptides from the renal proximal tubule, but it also operates in many other tissues and organs. Information regarding PepT2 in ... -
Functional modifications associated with gastrointestinal tract organogenesis during metamorphosis in Atlantic halibut (Hippoglossus hippoglossus)
Gomes, Ana Silva; Kamisaka, Yuko; Harboe, Torstein; Power, Deborah M.; Rønnestad, Ivar (Peer reviewed; Journal article, 2014-02-19)Background: Flatfish metamorphosis is a hormone regulated post-embryonic developmental event that transforms a symmetric larva into an asymmetric juvenile. In altricial-gastric teleost fish, differentiation of the stomach ... -
Hypothalamic agrp and pomc mRNA Responses to Gastrointestinal Fullness and Fasting in Atlantic Salmon (Salmo salar, L.)
Kalananthan, Tharmini; Murashita, Koji; Rønnestad, Ivar; Ishigaki, Mitsumasa; Takahashi, Kota; Silva, Marta Sofia; Wakabayashi, Yuki; Lai, Floriana; Shimizu, Munetaka; Nilsen, Tom Ole; Martinez, Enrique Pino; Gomes, Ana S. (Journal article; Peer reviewed, 2020-02-11)The orexigenic agouti-related protein (AgRP) and the anorexigenic pro-opiomelanocortin (POMC) are crucial players in the control of feed intake in vertebrates, yet their role in teleosts has not been fully established. ... -
Identification and characterization of the Atlantic salmon peptide transporter 1a
Gomes, Ana S.; Vacca, Francesca; Cinquetti, Raffaella; Murashita, Koji; Barca, Amilcare; Bossi, Elena; Rønnestad, Ivar; Verri, Tiziano (Journal article; Peer reviewed, 2020)Peptide transporter 1 (PepT1) mediates the uptake of dietary di-/tripeptides in vertebrates. However, in teleost fish gut, more than one PepT1-type transporter might operate, because of teleost-specific whole gen(om)e ... -
Impact of long-term fasting on the stomach-hypothalamus appetite regulating genes in Atlantic salmon postsmolts
Kalananthan, Tharmini; Folkedal, Ole; Gomes, Ana S.; Lai, Floriana; Handeland, Sigurd Olav; Tolås, Ingvill; Gelebart, Virginie; Rønnestad, Ivar (Journal article; Peer reviewed, 2023)Atlantic salmon will experience periods of fasting during its lifecycle. In nature, prolonged fasting periods occur owing to seasonal fluctuations in available feeds, migration or in relation to reproduction. In a culture ... -
Leptin receptor-deficient (knockout) zebrafish: Effects on nutrient acquisition
Del Vecchio, Gianmarco; Murashita, Koji; Verri, Tiziano; Gomes, Ana Cristina Da Silva; Rønnestad, Ivar (Journal article; Peer reviewed, 2021)In mammals, knockout of LEPR results in a hyperphagic, morbid obese, and diabetic phenotype, which supports that leptin plays an important role in the control of appetite and energy metabolism, and that its receptor, LEPR, ... -
Leucine did not stimulate growth and accretion in either stressed or unstressed Atlantic salmon
Espe, Marit; Lai, Floriana; Gomes, Ana S.; De Santis, Christian; Hartviksen, Mali B.; Holen, Elisabeth; Rønnestad, Ivar (Journal article; Peer reviewed, 2021)The aim of the current trial was to test whether leucine affected growth and accretion including test any effects on leucine upon stress. Quadruplicate tanks each containing 50 Atlantic salmon (Salmo salar) (mean start ... -
Light conditions during Atlantic salmon embryogenesis affect key neuropeptides in the melanocortin system during transition from endogenous to exogenous feeding
Norland, Sissel; Gomes, Ana S.; Rønnestad, Ivar; Helvik, Jon Vidar; Eilertsen, Mariann (Journal article; Peer reviewed, 2023)During the first feeding period, fish will adapt to exogenous feeding as their endogenous source of nutrients is depleted. This requires the development of a functional physiological system to control active search for ... -
Long-term welfare effects of repeated warm water treatments on Atlantic salmon (Salmo salar)
Moltumyr, Lene; Nilsson, Jonatan; Madaro, Angelico; Seternes, Tore; Winger, Fredrik Agerup; Rønnestad, Ivar; Stien, Lars Helge (Journal article; Peer reviewed, 2022)Warm water treatment has in recent years become widely used for ridding salmonids of sea lice in aquaculture although the consequences of the treatment for fish welfare are not adequately investigated. The objective of ... -
Loss of stomach, loss of appetite? Sequencing of the ballan wrasse (Labrus bergylta) genome and intestinal transcriptomic profiling illuminate the evolution of loss of stomach function in fish
Lie, Kai Kristoffer; Tørresen, Ole K.; Solbakken, Monica Hongrø; Rønnestad, Ivar; Tooming-Klunderud, Ave; Nederbragt, Alexander Johan; Jentoft, Sissel; Sæle, Øystein (Peer reviewed; Journal article, 2018-03-06)Background: The ballan wrasse (Labrus bergylta) belongs to a large teleost family containing more than 600 species showing several unique evolutionary traits such as lack of stomach and hermaphroditism. Agastric fish are ... -
Mapping key neuropeptides involved in the melanocortin system in Atlantic salmon (Salmo salar) brain
Norland, Sissel; Eilertsen, Mariann; Rønnestad, Ivar; Helvik, Jon Vidar; Gomes, Ana S. (Journal article; Peer reviewed, 2023)The melanocortin system is a key regulator of appetite and food intake in vertebrates. This system includes the neuropeptides neuropeptide y (NPY), agouti-related peptide (AGRP), cocaine- and amphetamine-regulated transcript ... -
The Melanocortin System in Atlantic Salmon (Salmo salar L.) and Its Role in Appetite Control
Kalananthan, Tharmini; Lai, Floriana; Gomes, Ana S.; Murashita, Koji; Handeland, Sigurd O; Rønnestad, Ivar (Journal article; Peer reviewed, 2020-08-21)The melanocortin system is a key neuroendocrine network involved in the control of food intake and energy homeostasis in vertebrates. Within the hypothalamus, the system comprises two main distinct neuronal cell populations ... -
Metabolic rates, feed intake, appetite control, and gut transit of clownfish Amphiprion ocellaris exposed to increased temperature and limited feed availability
Pham, Phuong Linh; Nguyen, Minh Van; Jordal, Ann-Elise Olderbakk; Rønnestad, Ivar (Journal article; Peer reviewed, 2022)Episodes of elevated temperature, combined with lower feed availability, are among the predicted scenarios of climate change representing a challenge for coral reef fish. We investigated the response of clownfish (Amphiprion ... -
Methionine deficiency does not increase polyamine turnover through depletion of hepatic S-adenosylmethionine in juvenile Atlantic salmon
Espe, Marit; Andersen, Synne Marte; Holen, Elisabeth; Rønnestad, Ivar; Veiseth-Kent, Eva; Zerrahn, Jens-Erik; Aksnes, Anders (Peer reviewed; Journal article, 2014-10)During the last few decades, plant protein ingredients such as soya proteins have replaced fishmeal in the diets of aquacultured species. This may affect the requirement and metabolism of methionine as soya contains less ... -
The ontogeny and brain distribution dynamics of the appetite regulators NPY, CART and pOX in larval Atlantic cod (Gadus morhua L.)
Le, Hoang T.M.D.; Angotzi, Anna Rita; Ebbesson, Lars O.E.; Karlsen, Ørjan; Rønnestad, Ivar (Peer reviewed; Journal article, 2016-04-21)Similar to many marine teleost species, Atlantic cod undergo remarkable physiological changes during the early life stages with concurrent and profound changes in feeding biology and ecology. In contrast to the digestive ... -
Ossification of Atlantic cod (Gadus morhua) – Developmental stages revisited
Sæle, Øystein; Haugen, Trine; Karlsen, Ørjan; van der Meeren, Terje; Bæverfjord, Grete; Hamre, Kristin; Rønnestad, Ivar; Moren, Mari; Lie, Kai Kristoffer (Peer reviewed; Journal article, 2017-02)In studies of marine larvae, it is common to use days post-hatch as a developmental reference point. We show that age is a poor measure of morphological and physiological development in Atlantic cod. Therefore, we propose ... -
PCB-126 spiked to polyethylene microplastic ingested by juvenile Atlantic cod (Gadus morhua) accumulates in liver and muscle tissues
Bogevik, André Sture; Ytteborg, Elisabeth; Madsen, Alexander Klevedal; Jordal, Ann-Elise Olderbakk; Karlsen, Odd Andre; Rønnestad, Ivar (Journal article; Peer reviewed, 2023)In the present study, polyethylene (PE) microplastics (150–300 μm) were added to Atlantic cod (Gadus morhua) feeds at 1 %, either in their present form (Virgin PE) or spiked with PCB-126 (Spiked PE). The feeds were given ... -
The peptide transporter 1a of the zebrafish Danio rerio, an emerging model in nutrigenomics and nutrition research: Molecular characterization, functional properties, and expression analysis
Vacca, Francesca; Barca, Amilcare; Gomes, Ana S.; Mazzei, Aurora; Piccinni, Barbara; Cinquetti, Raffaella; Del Vecchio, Gianmarco; Romano, Alessandro; Rønnestad, Ivar; Bossi, Elena; Verri, Tiziano (Peer reviewed; Journal article, 2019-12-19)Background: Peptide transporter 1 (PepT1, alias Slc15a1) mediates the uptake of dietary di/tripeptides in all vertebrates. However, in teleost fish, more than one PepT1-type transporter might function, due to specific whole ... -
Physical and nutrient stimuli differentially modulate gut motility patterns, gut transit rate, and transcriptome in an agastric fish, the ballan wrasse
Le, Hoang Thi My Dung; Lie, Kai Kristoffer; Etayo, Angela; Rønnestad, Ivar; Sæle, Øystein (Journal article; Peer reviewed, 2021-02-11)The effects of nutrient and mechanical sensing on gut motility and intestinal metabolism in lower vertebrates remains largely unknown. Here we present the transcriptome response to luminal stimulation by nutrients and an ... -
Rearing conditions and automated feed distribution systems for zebrafish (Danio rerio)
del Veccio, Gianmarco; Mazzei, Aurora; Schiavone, Roberta; Gomes, Ana S.; Frangelli, Giovanni; Sala, Tomasso; Fantino, Stefania; Brocca, Marco G.A.; Barca, Amilcare; Rønnestad, Ivar; Verri, Tiziano (Journal article; Peer reviewed, 2022)Zebrafish (Danio rerio) is a well-established animal model, used in a number of research areas. In the last decade, it has also emerged as a tool to evaluate the effects of diets and dietary components and to test novel ...