Publications

Here you will find publications from DTU Aqua:

Recent publications

2017
 

Uncontrollable chronic stress reduces growth disparities in farmed Atlantic salmon

Year: 2017

Uncontrollable chronic stress reduces growth disparities in farmed Atlantic salmon

Vindas, M. A., Madaro, A., Fraser, T. W. K., Höglund, E., Olsen, R. E., Kristiansen, T. S. & Øverli, Ø. 2017 In : Physiology & Behavior. 179, 246 p.

Publication: Research - peer-reviewJournal article – Annual report year: 2017

Individual variation in behavior and physiological traits in a wide variety of animals has been the focus of numerous studies in recent years. In this context, early life experiences shape responses that individuals have to subsequent environments, i.e. developmental plasticity. In this experiment, we subjected 10-month old fish to an unpredictable chronic stress (UCS) regime or no stress (control) for 3weeks. These individuals then underwent the parr-smolt transformation, when salmonids become adapted for the seawater environment, and were subsequently transferred into seawater before the final sampling. Biometric data was collected at the end of each period. Sampling on the final day was conducted in order to analyze basal monoaminergic activity in the brain stem and hypothalamus, as well as gene expression of target genes in the telencephalon. We found that post-hoc sorting of individuals by their serotonergic activity (high and low) resulted in the elucidation of growth and gene expression differences. UCS groups were found to have less growth disparities throughout the experiment, compared to control fish. Furthermore, we found brain serotonergic signaling and corticotropic releasing factor binding protein expression were positively associated with brain stem serotonergic activity, which is consistent with fish showing a stress reactivity neurophysiological profile. In conclusion, we here submit evidence that sorting individuals by their basal serotonergic activity levels may be a useful tool in the study of developmental plasticity. These results may thus apply directly to improving husbandry practices in aquaculture and elucidating neural mechanisms for coping behavior.
Original languageEnglish
JournalPhysiology & Behavior
Volume179
Number of pages246
ISSN0031-9384
DOIs
StatePublished - 2017

 

Effects of Dietary Digestible Protein and Energy Levels on Growth Performance, Feed Utilization, and Body Composition of Juvenile Permit, Trachinotus falcatus (Linnaeus, 1758): DIETARY PROTEIN AND ENERGY LEVELS FOR PERMIT JUVENILE

Year: 2017

A 9-wk study was conducted to evaluate the effect of dietary protein and energy on growth performance of juvenile permit, Trachinotus falcatus, growing from approximately 30 to 150g. Nine experimental diets were formulated to contain three levels of crude protein (400, 450, and 500g/kg dry matter [DM]); and three levels of crude lipid (100, 200, and 300g/kg DM) in a 3 x 3 factorial design. Growth rate and feed efficiency were significantly improved with increasing dietary protein levels from 400 to 500g/kg and with dietary lipid levels from 100 to 200g/kg. Fish body protein content was positively correlated with dietary ratio of digestible protein (DP) to digestible energy (DE) (P<0.01, R2=0.83), while body lipid was negatively correlated with dietary DP/DE (R2=0.55, P<0.05) but positively correlated with dietary DE levels (R2=0.66, P<0.01). Results showed a protein-sparing effect, as protein retention was significantly increased by increasing dietary lipid level. In conclusion, the diet containing DP of 392.7g/kg and DE of 18.8 MJ/kg (DM), corresponding to a DP/DE of 20.9g/MJ, is suggested as an optimal feed for growth and feed efficiency in juvenile permit.
Original languageEnglish
JournalJournal of the World Aquaculture Society
Number of pages10
ISSN0893-8849
DOIs
StatePublished - 2017

 

A spatiotemporal model for snow crab (Chionoecetes opilio) stock size in the southern Gulf of St. Lawrence

Year: 2017

A spatiotemporal model for snow crab (Chionoecetes opilio) stock size in the southern Gulf of St. Lawrence

Cadigan, N. G., Wade, E. & Nielsen, A. 2017 In : Canadian Journal of Fisheries and Aquatic Sciences. p. 1-13 13 p.

Publication: Research - peer-reviewJournal article – Annual report year: 2017

We develop a high-resolution spatiotemporal model of stock size and harvest rates for snow crab (Chionoecetes opilio) in the southern Gulf of St. Lawrence, which supports an economically important fishery off the east coast of Canada. It is a spatial and weekly model during 1997–2014 that utilizes within-season depletion based on catch per unit of effort (CPUE; kg·pot–1) and also biomass values from a survey designed specifically for this stock. The model is formulated in a state-space framework. The main contribution of the model is to provide a better understanding of fishery-dependent factors that affect CPUE. There is strong evidence of density dependence in the relationship with CPUE and stock biomass, in addition to a general increase in CPUE catchability over time that may be related to changes in gear soak time and spatial variation in catchability. We also find that a natural mortality rate of 0.4 provides a better fit to survey results. Model results suggest that there is no evidence of effort saturation in the fishery
Original languageEnglish
JournalCanadian Journal of Fisheries and Aquatic Sciences
Pages (from-to)1-13
Number of pages13
ISSN0706-652X
DOIs
StatePublished - 2017

 

Morphological, physiological and dietary covariation in migratory and resident adult brown trout ( Salmo trutta )

Year: 2017

Morphological, physiological and dietary covariation in migratory and resident adult brown trout ( Salmo trutta )

Peiman, K. S., Birnie-Gauvin, K., Larsen, M. H., Colborne, S. F., Gilmour, K. M., Aarestrup, K., Willmore, W. G. & Cooke, S. J. 2017 In : Zoology.

Publication: Research - peer-reviewJournal article – Annual report year: 2017

The causes and consequences of trait relationships within and among the categories of physiology, morphology, and life-history remain poorly studied. Few studies cross the boundaries of these categories, and recent reviews have pointed out not only the dearth of evidence for among-category correlations but that trait relationships may change depending on the ecological conditions a population faces. We examined changes in mean values and correlations between traits in a partially migrant population of brown trout when migrant sea-run and resident stream forms were breeding sympatrically. Within each sex and life-history strategy group, we used carbon and nitrogen stable isotopes to assess trophic level and habitat use; assessed morphology which reflects swimming and foraging ability; measured circulating cortisol as it is released in response to stressors and is involved in the transition from salt to freshwater; and determined oxidative status by measuring oxidative stress and antioxidants. We found that sea-run trout were larger and had higher values of stable isotopes, cortisol and oxidative stress compared to residents. Most groups showed some correlations between morphology and diet, indicating individual resource specialization was occurring, and we found consistent correlations between morphology and cortisol. Additionally, relationships differed between the sexes (cortisol and oxidative status were related in females but not males) and between life-history strategies (habitat use was related to oxidative status in male sea-run trout but not in either sex of residents). The differing patterns of covariation between the two life-history strategies and between the sexes suggest that the relationships among phenotypic traits are subjected to different selection pressures, illustrating the importance of integrating multiple phenotypic measures across different trait categories and contrasting life-history strategies
Original languageEnglish
JournalZoology
ISSN0944-2006
DOIs
StateAccepted/In press - 2017

 

Ål bliver i tusindvis udsat i vandløb, søer og kystnære områder

Year: 2017

Ål bliver i tusindvis udsat i vandløb, søer og kystnære områder

Sivebæk, F. & Pedersen, M. I. 2017 .

Publication: CommunicationInternet publication – Annual report year: 2017

Original languageDanish
Publication date2017
Source/PublisherFiskepleje.dk
StatePublished - 2017


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28 JULY 2017