Effects of oxygen levels and temperature on growth and physiology of pikeperch juveniles cultured in a recirculating aquaculture system.

This study aimed to understand how environmental factors, specifically water temperature and oxygen saturation, affect the growth performance and physiology of pikeperch (Sander lucioperca) juveniles in recirculating aquaculture systems (RASs). Given the importance of optimising growth conditions in aquaculture to maximise efficiency, it aims to assess whether different combinations of oxygen levels and temperatures can enhance growth while maintaining the physiological health and welfare of the fish. The experimental design included the culturing pikeperch juveniles (22.

Thermal tolerance of cultured and wild Icelandic arctic charr (Salvelinus alpinus) at self-selected flow rates.

Climate change is predicted to change not only the temperature of many freshwater systems but also flow dynamics. Understanding how fishes will fare in the future requires knowing how they will respond to both extended variations of temperature and flow. Arctic charr have had their thermal tolerance measured, but never with respect to flow.

The effect of temperature on growth performance and aerobic metabolic scope in Arctic charr, Salvelinus alpinus (L.).

In recent years, Arctic char populations in Iceland have declined and the objective of this experiment was to throw further light on these changes by examining the effect of temperature (5, 9, 13, 17, and 21 °C) on the survival, growth rate, metabolism, and physiological indices of juvenile Arctic charr (initial mean body mass 4.02 ± 0.8 g).

GSuite HyperBrowser: integrative analysis of dataset collections across the genome and epigenome.

Background: Recent large-scale undertakings such as ENCODE and Roadmap Epigenomics have generated experimental data mapped to the human reference genome (as genomic tracks) representing a variety of functional elements across a large number of cell types. Despite the high potential value of these publicly available data for a broad variety of investigations, little attention has been given to the analytical methodology necessary for their widespread utilisation.

Findings: We here present a first principled treatment of the analysis of collections of genomic tracks.

Antibody-secreting plasma cells persist for decades in human intestine.

Plasma cells (PCs) produce antibodies that mediate immunity after infection or vaccination. In contrast to PCs in the bone marrow, PCs in the gut have been considered short lived. In this study, we studied PC dynamics in the human small intestine by cell-turnover analysis in organ transplants and by retrospective cell birth dating measuring carbon-14 in genomic DNA.

Effects of short-day treatment on long-term growth performance and maturation of farmed Arctic charr Salvelinus alpinus reared in brackish water.

The effects of a 6 week short-day photoperiod followed by continuous light, applied during the juvenile phase of Arctic charr Salvelinus alpinus in fresh water on smoltification and on the long-term growth and maturity following transfer to brackish water (BW) (constant salinity of either 17 and 27 or increasing salinity in steps from 17 to 27) were investigated. Prior to salinity transfer, the juveniles were either reared at continuous light (C group) or reared for 6 weeks on a short day (8L:16D, S group) followed by continuous light (24L:0D). Increased salinity had negative effect on growth, with female fish reared at 17 salinity weighing 19 and 27% more than the salinity-step group (17-27) and the 27 salinity group, respectively.

Long-term rearing of Arctic charr Salvelinus alpinus under different salinity regimes at constant temperature.

Arctic charr Salvelinus alpinus of the Hólar strain (mean ± s.e. body mass = 152·1 ± 3·1 g) were reared at four different salinity regimes at a constant temperature of 7·4° C.

Changes in arterial oxygen tension and physiological status in resting, unrestrained Arctic charr Salvelinus alpinus (L.) exposed to mild hypoxia and hyperoxia.

In arctic charr Salvelinus alpinus, arterial blood partial pressures of oxygen (PaO2) and carbon dioxide increased with increasing water oxygen tension (PwO2), while the water to arterial PO2 difference (PwO2-PaO2) did not change in relation to PwO2.

Characterisation and expression of the paired box protein 7 (Pax7) gene in polymorphic Arctic charr (Salvelinus alpinus).

Arctic charr (Salvelinus alpinus L.) from Lake Thingvallavatn, Iceland occur as four distinct morphs: large benthivorous (LB), dwarf benthivorous (DB), piscivorous (PI) and planktonivorous (PL). The morphs differ with respect to body size, head morphology, growth rate, and life history.

Postprandial intestinal blood flow, metabolic rates, and exercise in Chinook salmon (Oncorhynchus tshawytscha).

Following a relatively large meal (2% body mass of dry pellets), intestinal blood flow in chinook salmon (Oncorhynchus tshawytscha) increased significantly, up to 81%, between 14 and 29 h postprandially. Also, 15 h postprandially, oxygen consumption (M(2)) was elevated by 128% compared with a measurement of routine M(2) made after 1 wk of fasting. The postprandial increase in MO(2) (the heat increment) was 33 micromol O(2) min(-1) kg(-1).

Effects of high intensity exercise training on cardiovascular function, oxygen uptake, internal oxygen transport and osmotic balance in chinook salmon (Oncorhynchus tshawytscha) during critical speed swimming.

To examine cardiorespiratory plasticity, cardiovascular function, oxygen consumption, oxygen delivery and osmotic balance were measured at velocities up to critical swimming speed (Ucrit) in seawater-adapted chinook salmon. We used two groups of fish. The control group had swum continuously for 4 months at a low intensity (0.

Gut blood flow in fish during exercise and severe hypercapnia.

This paper reviews the effects of exercise and hypercapnia on blood flow to the splanchnic circulation. Brief struggling behaviours are known to decrease blood flow to the gut (GBF). Likewise, prolonged swimming in unfed fish has been shown to reduce GBF in proportion to the increased oxygen uptake.

Gastrointestinal blood flow in the red Irish lord, Hemilepidotus hemilepidotus: long-term effects of feeding and adrenergic control.

Cardiac output, blood flow to the coeliac and mesenteric arteries, dorsal aortic blood pressure and heart rate were recorded simultaneously at rest and postprandial for 6 days in a teleost, the red Irish lord (Hemilepidotus hemilepidotus). We anticipated that gastrointestinal blood flow would increase postprandially, supported by an increase in cardiac output. However, we had no predictions for either the exact time-course of this response, or for the regional distribution of blood flow between to the two major arteries comprising the splanchnic circulation.

The interaction between O2 and CO2 exchange in rainbow trout during graded sustained exercise.

A quantitative analysis of O2 and CO2 transport was conducted in resting and exercising rainbow trout, and these data were used to quantify the magnitude of coupling between O2 and CO2 exchange, in vivo. The release of Bohr protons during haemoglobin-oxygenation was non-linear over the Hb-O2 equilibrium curve used in trout subjected to different levels of sustained exercise. At low swimming speeds, when venous blood O2 content (CvO2) was high, there was a small acidosis as blood passed through the gills, indicating more protons were released during oxygenation of Hb than were consumed during HCO3- dehydration.

CO2 transport and excretion in rainbow trout (Oncorhynchus mykiss) during graded sustained exercise.

A quantitative analysis of CO2 transport and excretion was conducted in seawater acclimated rainbow trout (Oncorhynchus mykiss) swimming at different sustained swimming velocities. CO2 excretion increased linearly with cardiac output during exercise but arterial P(CO2) (Pa(CO2)) and total CO2 levels also increased indicating a diffusion limitation to CO2 excretion. The elevated Pa(CO2) was not accompanied by a decrease in pH, indicating that the acid-base compensation was rapid.

Energy turnover in the normoxic and anoxic turtle heart.

We examined the possibility that the heart of the tuttle Chrysemys scripta is an exceptional anaerobic performer, by measuring myocardial power output, lactate output, and estimated ATP turnover in perfused heart preparations. Over a range of myocardial power outputs at 5 and 15 degrees C we find that turtle hearts perfused with anoxic saline do not show a particularly outstanding ability to produce ATP anaerobically. Furthermore, at 15 degrees C anoxia reduced the ATP turnover rate to 50% of the normoxic rate.

11-Ketotestosterone suppresses interrenal activity in rainbow trout (Oncorhynchus mykiss).

Interrenal activity in relation to sexual maturity in male rainbow trout, and the effects of in vivo treatment with 11-ketotestosterone (11-KT) were investigated. Silastic pellets containing either 11-KT or no steroid were implanted in maturing male and immature male and female rainbow trout for a total of 11 weeks. Two weeks before termination of the experiment, animals were subjected to crowding, and blood samples were taken 15-90 min after initial disturbance.

Hematocrit in oxygen transport and swimming in rainbow trout (Oncorhynchus mykiss).

The optimal hematocrit (Hctopt) hypothesis was tested by altering Hct (and arterial blood oxygen content, CaO2) between extreme states of anemia and polycythemia (Hct = 8-55%) in the rainbow trout. Since blood viscosity (eta) effects on cardiac output (Q) and O2 transport (TO2) are likely to be greatest when O2 demand and Q are maximal, we challenged fish to swim to their critical swimming velocity (Ucrit) in a swim-tunnel respirometer at 13 degrees C and measured maximal oxygen uptake (VO2max), maximum Q(Qmax), and other cardiovascular variables. In addition, experimental temperature was lowered to 5 degrees C to increase eta.

MECHANICAL PERFORMANCE OF AN IN SITU PERFUSED HEART FROM THE TURTLE CHRYSEMYS SCRIPTA DURING NORMOXIA AND ANOXIA AT 5 C AND 15 C.

We developed an in situ perfused turtle (Chrysemys scripta) heart preparation to study its intrinsic mechanical properties at 5°C and 15°C using normoxic and anoxic perfusion conditions. The in situ preparation proved durable and stable. At 15°C and a spontaneous heart rate of 23.

Smoltification induced by a 'skeleton' photoperiod in underyearling coho salmon (Oncorhynchus kisutch).

Underyearling coho salmon fry were subjected to three initial photoperiod treatments (6L∶18D, 10L∶14D, 14L∶10D) for two months and subsequently to three final treatments (16L∶8D, 9L∶6D∶1L∶8D, 10L∶14D) in a factorial design. Growth rates and seawater adaptability were monitored regularly. The groups that were exposed initially to 6L∶18D or 10L∶14D and then to 16L∶8D grew faster and had lower plasma sodium ion levels after seawater challenge tests than any of the other groups.