Portable clinical analysers, such as the i-STAT system, are increasingly being used for blood analysis in animal ecology and physiology because of their portability easy operation. Although originally conceived application to replace robust but lengthy techniques, researchers have extended use system outside humans even poikilothermic fish, with only limited validation. The present study analysed a range parameters [pH, haematocrit (Hct), haemoglobin (Hb), HCO3 (-), partial pressure CO2...

ABSTRACT Oxygen supply to the heart of most teleosts, including salmonids, relies in part or whole on oxygen-depleted venous blood. Given that plasma-accessible carbonic anhydrase (CA) red muscle rainbow trout has recently been shown facilitate oxygen unloading from arterial blood under certain physiological conditions, we tested hypothesis CA is present lumen coho salmon (Oncorhynchus kisutch) hearts, and may therefore assist luminal spongy myocardium, which no coronary circulation. We...

A successful spawning migration in salmon depends on their athletic ability, and thus efficient cardiovascular oxygen (O 2 ) transport. Most teleost fishes have highly pH-sensitive haemoglobins (Hb) that can release large amounts of O when the blood is acidified at tissues. We hypothesized plasma-accessible carbonic anhydrase (paCA; enzyme catalyses proton production from CO required to acidify tissues promote tissue extraction. Previous studies reported an elevated extraction...

Previously, we showed that the evolution of high acuity vision in fishes was directly associated with their unique pH-sensitive hemoglobins allow O 2 to be delivered retina at PO s more than ten-fold arterial blood (Damsgaard et al., 2019). Here, show strong evidence vacuolar-type H + -ATPase and plasma-accessible carbonic anhydrase vascular structure supplying act together acidify red cell leading secretion. In vivo data indicate this pathway primarily affects oxygenation inner involved...

Jatropha curcas (L.) is a multipurpose and drought-resistant tree, widespread throughout the tropics subtropics. Its seeds are rich in oil protein (contains 600–660 g kg−1 crude similar to fish meal). It being promoted as biofuel plant. kernel meal obtained after extraction an excellent source of protein. However, presence toxic antinutritional constituents restricts its use shrimp feed. An 8-week experiment was conducted evaluate nutritional quality detoxified (DJKM) white leg (Litopenaeus...

Accurate measurements of blood gases and acid–base status require an array sophisticated laboratory equipment that is typically not available during field research; such the case for many studies on stress physiology, ecology conservation elasmobranch fish species. Consequently, researchers have adopted portable clinical analysers were developed analysis human characteristics, but often without thoroughly validating these systems their use fish. The aim our study was to test suitability...

Every year, bar-headed geese ( Anser indicus ) perform some of the most remarkable trans-Himalayan migrations, and researchers are increasingly interested in understanding physiology underlying their high-altitude flight performance. A major challenge is generating reliable measurements blood parameters on wild birds field, where established analytical techniques often not available. Therefore, we validated two commonly used portable clinical analysers (PCAs), i-STAT HemoCue systems, for...

Pacific hagfish, Eptatretus stoutii, can recover from 36 h of anoxia at 10°C. Such tolerance demands the mobilization anaerobic fuels and removal metabolic wastes, processes that require a functional heart. The purpose this study was to measure response excised, cannulated hagfish heart using direct calorimetry. These experiments were coupled with measurements cardiac pH metabolite concentrations, multiple time points, monitor acid-base balance ATP-production. We also exposed compare in...

The effect of an isoenergetic replacement dietary fat by starch, on chyme characteristics and water fluxes in the gastro intestinal tract (GIT) was assessed. Adult African catfish (Clarias gariepinus) were fed a starch (SD) or (FD) diet groups fish dissected at 2, 5 8 h after consumption single meal. Chyme collected quantitatively analysed for osmolality dry matter (DM) content. Postprandial calculated, while using yttrium oxide (Y2O3) as inert marker to account absorption DM along GIT....

We used respirometric theory and a new respirometry apparatus to assess for the first time sequential oxidation of major metabolic fuels during post-prandial period (10 h) in adult zebrafish fed with commercial pellets (51% protein, 2.12% ration). Compared fasted group, fish presented peak increases oxygen consumption (78%), carbon dioxide (80%) nitrogen excretion rates (338%) at 7-8 h, remained elevated 10h. Respiratory quotient increased slightly (0.89 0.97) whereas greatly (0.072 0.140),...

In all vertebrates studied to date, CO2 excretion depends on the enzyme carbonic anhydrase (CA) that catalyses rapid conversion of HCO3− at gas-exchange organs. The largest pool CA is present within red blood cells (RBC) and, in some vertebrates, plasma-accessible (paCA) isoforms participate excretion. However, teleost fishes typically do not have paCA gills and reliant entirely RBC CA; a strategy possible icefishes. As result natural knockout, Antarctic icefishes (Channichthyidae) are only...

The development of chyme characteristics and the in vivo digestion crude protein (CP) were assessed response to different dietary sources non-protein energy. African catfish (Clarias gariepinus) fed a starch or fat diet for 28 days, faecal CP apparent digestibility coefficient (ADC) was determined by marker method. After consumption single meal, collected from four compartments gastrointestinal tract viscosity, dry matter (DM), concentration measured. Replacing resulted lower ADC (P < 0.05),...

Acute (<96 h) exposure to elevated environmental CO2 (hypercarbia) induces a pH disturbance in fishes that is often compensated by concurrent recovery of intracellular and extracellular (pHi pHe, respectively; coupled regulation). However, regulation may be limited at partial pressure (PCO2 ) tensions far below levels some naturally encounter. Previously, four hypercarbia-tolerant had been shown completely rapidly regulate heart, brain, liver white muscle pHi during acute >4 kPa PCO2...

The gills of most teleost fishes lack plasma-accessible carbonic anhydrase (paCA) that could participate in CO2 excretion. We tested the prevailing hypothesis paCA would interfere with red blood cell (RBC) intracellular pH regulation by β-adrenergic sodium-proton exchangers (β-NHE) protect pH-sensitive haemoglobin-oxygen (Hb-O2) binding during an acidosis. In open system mimics gills, β-NHE activity increased Hb-O2 saturation a respiratory acidosis presence or absence paCA, whereas effect...

Accumulating evidence is highlighting the importance of a system enhanced hemoglobin-oxygen (Hb-O2) unloading for cardiovascular O2 transport in teleosts. Adrenergically stimulated sodium-proton exchangers (β-NHE) create H+ gradients across red blood cell (RBC) membrane that are short-circuited presence plasma-accessible carbonic anhydrase (paCA) at tissues; result large arterial-venous pH shift greatly enhances from pH-sensitive Hb. However, RBC intracellular (pHi) must recover during...

Pacific spiny dogfish (Squalus suckleyi) have been widely used as a representative species for chondrichthyan CO2 excretion. slower red blood cell (RBC) carbonic anhydrase (CA) isoform than teleost fishes, extracellular CA activity, no endogenous plasma inhibitor, and plasma-accessible IV at the gills. Thus, both RBC compartments contribute to bicarbonate ion (HCO3-) dehydration gills excretion in contrast which HCO3- is restricted RBCs. We compared activity levels, subcellular localization,...

Abstract Aim To identify the physiological role of acid‐base sensing enzyme, soluble adenylyl cyclase (sAC), in red blood cells (RBC) model teleost fish, rainbow trout. Methods We used: (i) super‐resolution microscopy to determine subcellular location sAC protein; (ii) live‐cell imaging RBC intracellular pH (pH i ) with specific inhibition (KH7 or LRE1) its cellular regulation; (iii) spectrophotometric measurements haemoglobin–oxygen (Hb‐O 2 binding steady‐state conditions; and (iv) during...

Soluble adenylyl cyclase (sAC) is a HCO3 - -stimulated enzyme that produces the ubiquitous signalling molecule cAMP, and deemed an evolutionarily conserved acid-base sensor. However, its presence not yet confirmed in bony fishes, most abundant diverse of vertebrates. Here, we identified sAC genes various cartilaginous, ray-finned lobe-finned fish species. Next, focused on rainbow trout (rtsAC) 20 potential alternative spliced mRNAs coding for protein isoforms ranging size from 28 to 186 kDa....

The present study describes and validates a novel yet simple system for simultaneous in vivo measurements of aquatic CO2 production (MCO2) oxygen consumption (MO2) rates, thus allowing the calculation respiratory exchange ratios (RER). Diffusion from phase into gas phase, across hollow fibre membrane, enabled MCO2 with high-precision infrared analyser. MO2 was measured PO2 optode using stop-flow approach. Injections known amounts apparatus yielded accurate highly reproducible content...