Pneumatic Duct Research Articles

Migration and development of swim-bladder nematodes, Cystidicola spp. (Habronematoidea), in their definitive hosts

Third-stage larvae of Cystidicola cristivomeri White, 1941, and C. farionis Fischer, 1798, migrated directly via the pneumatic duct to the swim bladder of lake trout, Salvelinus namaycush, and rainbow trout, Salmo gairdneri, respectively. Larvae reached the swim bladder as early as 16 h after fish were infected using a stomach tube. At 4–10 °C, mature male and female C. cristivomeri and C. farionis were first recovered 67 and 210 days, and 112 and 235 days, respectively, after infection. Cystidicola cristivomeri is probably long-lived; there was no evidence that any died in lake trout infected for up to 600 days.Large numbers of third-stage cystidicolid larvae accumulated without maturing in the swim bladder of naturally infected lake whitefish, Coregonus clupeaformis, from Lake Nipigon, northwestern Ontario. When given to rainbow trout, these larvae matured and the adult nematodes were identical to C. farionis. These results suggest that the swim-bladder nematode that matures in lake whitefish is a distinct species.

A study of the histology and morphology of the digestive tract of the common eel (Anguilla anguilla)

The anatomy and morphology of the digestive tract of the eel was examined using light and scanning electron microscopy. The oeosphagus showed complex longitudinal folding; stratified epithelium, columnar epithelium and goblet cells striated muscle fibres formed the thick muscular coat. The pneumatic duct entered the oesophagus anterior to the oesophagastric junction. The Y shaped stomach showed large well developed folds which decreased in size and number towards the pyloric sphincter. Columnar epithelium and gastric gland cells were present, the latter being absent from the pyloric region.The intestine had a heavily thickened anterior region, signs of convulation were noted prior to the ileorectal valve. Intestinal folding showed a complex reticulate pattern with columnar epithelium and goblet cells present. The mucopolysaccharides were studied in the goblet and columnar cells throughout the regions of the gut. Lymphocytes and eosinophilic type cells were found in the connective tissue of the mucosa throughout the gut. The pancreas was a compact organ with few Islets of Langerhans, beta cells were peripherally situated and alpha cells centrally. The unilobular liver acted as a storage organ for oil and glycogen.

Ultrastructure of the swim bladder of the goldfish, Carassius auratus.

The swim bladder of the cyprinid Carassius auratus (goldfish) is a two-chambered organ connected to the esophagus by a pneumatic duct. The anterior chamber is lined by a single type of squamous epithelial cell. Two types of epithelial cells are present in the posterior chamber. Flattened cells with differences in the electron density of the cytoplasm line most of the chamber. Darker cells generally contain large amounts of glycogen. Cuboidal epithelial cells also occur in the posterior chamber. A glandular layer external to the muscularis in the posterior chamber is composed of large cells containing little glycogen, an extensive Golgi apparatus, and numerous mitochondria with single large granules. Capillaries and nerves are present in large numbers in this layer. Blood vessels form micro-retia mirabilia in the submuscular layer external to the glandular layer. Vessels are of two distinct types with wide lumina and flattened endothelium characterizing the venous vessels. Arterial vessels and have smaller lumina, thick endothelial cells with prominent pinocytotic vesicles, and surrounding pericytes. Collagen is present in three forms in this swim bladder - large tactoids in the tunica externa of the anterior chamber, smaller tactoids in the lamina propria of the posterior chamber, and small fibrils in all other areas.

Initial swim bladder inflation in the larvae of Tilapia mossambica (Peters) and Morone saxatilis (Walbaum)

Tilapia and striped bass larvae inflate their swim bladders on the 7th–9th and 5th–7th days after hatching, respectively. The primordial bladder of Tilapia has no pneumatic duct and larvae do not gulp atmospheric gas for the initial swim bladder inflation. Prominent columnar epithelium is characteristics of the bladder of Tilapia prior to inflation. Hypoxic conditions inhibit inflation and result in degeneration of the columnar epithelium and the irreversible malfunction of the swim bladder. The swim bladder of the striped bass has a glandular epithelium and a pneumatic duct prior to inflation. The mode of the initial inflation and functional role of the pneumatic duct remain unclear, although strong aeration and turbulent water in the rearing containers were observed to be main factors enhancing normal inflation of the larval swim bladder.

The effect of respiratory stress on carp haemoglobin

1. 1. The effects of hypoxia, hyperoxia and hypercapnia on blood pH, pCO 2, pO 2, glucose, haematocrit and haemoglobin were investigated in the carp. Cyprinus carpio, with patent and ligated pneumatic ducts. 2. 2. Hypoxia and hypercapnia produced decreases in blood pH and pO 2 values and increases in blood pCO 2, glucose, haematocrit and haemoglobin values whereas hyperoxia increased only blood pO 2 and pCO 2 values in fish with patent pneumatic ducts. Some of these changes were more pronounced in ligated animals. 3. 3. Polyacrylamide gel electrophoresis of haemoglobin showed no significant changes in percentage composition during hypoxic conditions or during hyperoxia whereas hypercapnia caused definite changes in normal animals. Sham-operated and ligated fish showed a variety of changes for similar treatments. 4. 4. It is concluded that hypoxic conditions involve no conformational changes in carp haemoglobin and that variations in the organic phosphate level of the erythrocytes are probably responsible for the changes in oxygen affinity of carp haemoglobin. Abnormal conditions, on the other hand, cause pronounced effects possibly attributable to the involvement of different erythrocyte populations in the transport of various haemoglobin fractions.

Studies on Disease Owing to Erroneous-Swallowing in Ayu Fry

In the process of artificial production of Ayu fry (Plecoglossus altivelis), considerable mortalities of the fry (aged one to two months) were frequently found. Each of these dead fish had a white girdle along the spinal cord, apparently showing the characteristic of the disease.Fourty one of the diseased fish were histopathologically investigated by the present authors. All the diseased fish erroneously swallowed the diets through the pneumatic duct into the swim bladder, without transferring into the alimentary canal. In 39 fish, the lumen of the swim bladder showed hyperplasia or necrosis due to bacteria, which probably multiplied abruptly in the organ. In 2 fish, a great number of fungi were observed in the diet found in the swim bladder; some organs (kidney and body musculature) near the swim bladder were remarkably affected by the fungi.From the present work, it is considered that the erroneous-swall-owing of diet causes the mortalities of Ayu fry.

Respiration of the air breathing fishPiabucina festae

Piabucina festae, a Central American stream fish, breathes air frequently, even in air saturated water, however, is not an obligate air breather. Without access to air, it can maintain routine\(\dot V_{O_2 }\) by aquatic respiration down to aPwO2 of about 70 Torr which is its critical O2 tension (PcO2, Fig. 5). Aerial respiration averages 10% of total\(\dot V_{O_2 }\) in air saturated water and 70% in hypoxic water (Fig. 4). At lowPwO2 air breathing is more frequent (Fig. 1), and more O2 is utilized from each air breath (Table 3), and tidal volume may increase (Fig. 7). Vascularized respiratory compartments or cells (Fig. 6), located in the second chamber of the physostomus gas bladder, function for aerial respiration. In ventilation air is gulped and forced through a large pneumatic duct into the gas bladder, excess gas is then released through opercula. Inspiration always precedes expiration and tidal volume is small, keeping gas bladderPO2 low (Table 4). Major differences in the air breathing physiology ofP. festae and other species are its higherPcO2, a low aerial\(\dot V_{O_2 }\) in normoxic water, even though air gulps are frequent, and its pattern of inhalation prior to expiration. The interrelationship and optimization of the three gas bladder functions (buoyancy, sound reception, and air breathing) inP. festae is discussed. Aerial respiration may have evolved secondarily to the gas bladder's function in buoyancy control.

AN OUTBREAK OF MYXOBACTERIAL DISEASE IN COHO SALMON (Oncorhynchus kisutch) REARED IN A MAINE ESTUARY

An epizootic of a myxobacterial infection in coho salmon (Oncorhynchus kisutch) was responsible for the death of 50,000 fish, 30% of the population. Cartiage in the nose, mouth and lower jaw was eroded, and yellow sheets of bacterial growth were observed in the mouth, pharynx and pneumatic duct. The severity of the disease increased with increasing water temperature. Pathogenicity trials were inconclusive; only two of 18 experimentally infected fish succumbed to the disease. However, the lesions, and the absence of other known pathogens suggests the myxobacterium was responsible.

Noise Reduction in Pneumatic Ducts That Convey Peanut Hulls

ABSTRACT NOISE measurements in peanut shelling plants revealed that pneumatic ducts that convey peanut hulls are a major source of noise. Noise was found to increase with air velocity and turbulence and to decrease with in-creased duct wall thickness. Numerous treatments were evaluated for their effectiveness in reducing noise. Covering the ducts with commonly available thermal insulation was the most effective treatment, considering cost and convenience. However, treat-ing the ducts with a mastic compound offered advantages and should be considered in some instances. Special acoustic materials were generally con-sidered to be too costly.

Notes on the Egg Deposition, Larval Migration and Intermediate Host of the Nematode Anguillicola crassa Parasitic in the Swimbladder of Eels

A. crassa deposits its thin-membraned eggs already containing fully formed sheathed-larvae in the lumen of the swimbladder. Occasionally eggs are released in large numbers by rupture of the body wall and uterus. The sheathed-larvae hatched out in the lumen of the swimbladder are passed through the pneumatic duct and digestive tract into the water, where they can survive for some months without shedding the sheath. Part of the larvae invade the wall tissues of the swimbladder, though their fate is not known.The larvae eaten by the copepod Eucyclops serrulatus pierce the intestinal wall and penetrate the body cavity within a few days at the latest, in which they start to grow immediately. The larvae moved to the body cavity have no sheath. On the contrary the larvae eaten by Sinodiaptomus chaffanjoni can penetrate the body cavity, but no copepod habouring the larvae in its body cavity can be found 24 hours after infection. This fact is possibly due to death of the infected copepods.

ANATOMY OF THE SWIMBLADDERS OF SEVEN FAMILIES OF TRANSVAAL FRESHWATER FISHES

SUMMARY IN the genera Barbus and Labeo of the family Cyprinidae there is a typical twolobed, cylindrical swimbladder: a shorter anterior and a longer posterior lobe, connected by an isthmus. The pneumatic duct passes from the anteroventral end of the posterior lobe to the oesophagus. In the genus Labeo two spiral bands encircle the posterior lobe twice. No rete mirabile, nor any indication of a gas gland, was observed. The species Hydrocynus vittutus of the family Characidae has a very similarly shaped swimbladder to that of the Cyprinidea. Inside the anterior lobe, however, there is a peculiar structure, which is evidently the gas glad, although a rete mirabile was not observed. In the families of the Siluriformes, studied, with the exception of the Clariidae, a single lobed, heartshaped swimbladder is present. It is divided by a longitudinal and a transverse. septum into three chambers: an anterior, a right and a left posterior chamber. The pneumatic duct originates from the medial posteroventral part of the anterior chamber. In Clarias gariepinus the two-lobed, right and left lobed, swimbladder lies in a bony capsule, which is attached transversely to the posteroventral part of the skull. In all the Siluriformes, studied, no trace of a gas gland, nor of a rete mirabile was found. The Cichlid swimbladder has no pneumatic duct, nor any other exit, hence it is physoclistic. In the Cichlids the retroperitoneal position of the swimbladder is accentuated, as the peritoneum and the outer tectum of the swimbladder have united to form a thick, tough membrane, which divides the body cavity into a distinct ventral, or visceral cavity, and a dorsal, or swimbladder cavity. The swimbladder cavity acts as an outer swimbladder. It contains an inner, smaller bladder whose internal ventro-anterior surface is covered with arborescently arranged patches of gas glands. The attachment of the swimbladder to the tripus and also to the ossa suspensoris is discussed.

Genetic differences in susceptibility to two diseases among strains of the common carp

In a test involving 5 inbred strains, and 9 strain crossbreds of the common carp, one inbred strain was found to be infected by Epidermal epithelioma disease and a second inbred strain was infected by a swim bladder inflammation. Crossbreds between these 2 strains, as well as between them and other strains did not show a single fish infected by either disease. It was concluded that susceptibility to both of these diseases is controlled by recessive genetic factors. It appears that the decreased incidence of Epidermal epithelioma in Israeli fish ponds in recent years has been due to the increased use of selected crossbred carp fry. The incidence of Epidermal epithelioma was twice as high in experimental ponds with a high stocking rate than in those with a lower stocking rate. The swim bladder inflammation was apparently due to a blockage of the pneumatic duct, with secondary infection by Aeromonas liquefaciens.

The Permeability to Gases of the Swimbladder of the Conger Eel(Conger Conger)

The permeability properties of the silvery walls of the swimbladders of eels(Conger congerandAnguilla anguilld)have been studied. The intact swimbladder wall is very much more impermeable to carbon dioxide, oxygen and nitrogen than ordinary connective tissue. Removal of the silvery layer of the wall, which contains crystals of guanine with a little hypoxanthine, increases the permeability about 100 times and leaves a transparent ‘epithelial’ layer only a little less permeable than connective tissue to these gases. The wall of the pneumatic duct of the conger swimbladder, which is not silvered, has permeability properties similar to those of connective tissue. In long-lasting experiments a production of carbon dioxide not coupled to oxygen usage was detected in the epithelial layer. The ratios between the diffusion constants of CO, N and O for both the silvery and epithelial layers show that diffusion probably takes place through water-filled pathways, and calculations show that impermeable overlapping crystals embedded in the silvery layer could account for its very low permeability. Two deep-sea eels were shown to have swimbladders whose walls contained about 10 times more guanine/unit area than the conger eel. The possibility that layers of guanine crystals may divide fish into compartments is discussed.

The volume and rate of volume change of the swimbladder of the goldfish

The volumes of the swimbladders of 7 unanesthetized goldfish ( carassius auratus), ranging in weight from 20.0 to 40.2 g and kept in water at a constant temperature of 29 °C, were measured by displacement plethysmography. The plethysmograph was located inside a hyperbaric chamber so that pressure could be applied to the fish without applying pressure across the walls of the plethysmograph. The mean volume of the swimbladders was 1.78 (S.D. ± 0.010) ml. The volumes of the swimbladders were measured again periodically after some gas had escaped through the pneumatic ducts during a brief exposure of the fish to a partial vacuum. The mean rate of change of the volume of the swimbladder was 0.22 (S.D. ± 0.08) ml 24 hr, independent of the weight of the fish; initial swimbladder volume ; volume of gas expelled ; or change in specific gravity of the fish. In 3 other fish exposed to a constant ambient pressure of 1.5, 1.75, or 2.0 atm, the rate of volume change of the partly evacuated swimbladder was + 0.056, − 0.025 and − 0.065 ml 24 hr. It is concluded that the net transfer of gas into the swimbladder of a goldfish is affected by the ambient pressure.

Factors Influencing the Aerial Breathing and Metabolism of Gars (Lepisosteus)

Several factors influencing the rate of aerial breathing and metabo- lism of young-of-year gars were studied. Without access to atmospheric oxygen, the lethal oxygen concentration was found to be approximately 2.45 mg/1 at 73F. The average rate of oxygen consumption of these fishes was 0.295 ml 0,/gm/hr. Pre- vention of aerial breathing produced no observable ill effects on the gars tested pro- vided the dissolved oxygen content of the water was above 3 mg/1. Undoubtedly, the gar's air bladder serves a hydrostatic function as well as a respiration function, and thus complicates the analysis of aerial breathing of these fishes. The temperature acclimation time of alligator gar, based on the rate of aerial breathing, requires ap- proximately 48 hours. INTRODUCTION. Biologists who first described the habits of Lep- isosteus believed that the swim bladder of this fish preformed a respi- ratory function. This belief was based on several observations: (1) the internal surface of the walls of the swim bladder are cellular and spongy; (2) a rich network of capillaries supplies blood to this organ; (3) a pneumatic duct connects the swim bladder with the pharynx and a glottis is present at this connection; and (4) gars often appear to gulp air. Investigations by Potter (1927) showed that gar could live 20 days in deoxygenated water if permitted to gulp air at the surface. Con- versely, he found that gar could live and apparently remain healthy for several days when confined below the surface, if they were main- tained in oxygenated water. He also demonstrated that there was an exchange of gases in the swim bladder resulting in a decrease in the percentage of oxygen and an increase in the percentage of carbon dioxide between inhalations. From this, he concluded that the swim bladder of Lepisosteus is an organ of supplementary respiration. Working with the longnose gar, L. osseus, and the spotted gar, L. oculatus, Saksena (1963) showed a significant increase in the rate of aerial breathing for both species with a rise in water temperature. He 45

Double‐mouth deformity in a trout (Salmo trutta) and its cause

Gudger (1930) ends an article on this deformity by stating that double‐mouth deformity in fishes is always due to injury so far as our present knowledge goes. The feature common to all cases is displacement of the lower end of the hyoid arch downwards and backwards through a gap in the mouth floor. This occurs because the protractor muscles of the arch have been put out of action, usually by severe accidental injury. The retractor muscles, thus left unopposed, pull the lower end of the arch into the deformed position. It is difficult to imagine how accidental wound could produce the condition seen in the Shetland trout. Here is only a cleft like a clean cut in the midline of the mouth floor ending at the displaced arch. There is neither irregular scarring nor obvious tissue loss, the head retaining its bilateral symmetry. In it the protractors of the arch must also have been destroyed, but probably by some other kind of damage than wound from without. With this possibility in mind I wrote to the managers of several trout‐farms, enclosing a sketch of the deformity. Each was asked if he had come across anything like it when grading his stock. One letter in the affirmative suggested that air trapped in the floor of the mouth might be the cause. Later the writer sent me two young trout, radiographs of which confirmed this statement and led me to think that obstruction of the pneumatic duct might account for the trapped air. The consequences of extirpation of the swimbladder in physostomes explains how the trapped air is permanently at increased pressure, and supports this hypothesis.

Sounding Response of the Kokanee and Sockeye Salmon

When frightened, sockeye and kokanee salmon dive into deeper waters. This is termed the "sounding response."The sounding response in these fish is accompanied by the expulsion of gas from the swimbladder via the pneumatic duct. This gas loss is active and results from the contraction of the circular muscle fibers in the wall of the swimbladder.Gas loss on sounding is reduced or obviated after exposure to adrenergic blocking agents and enhanced in fish treated with sympathomimetics. Circular muscle fibers in intact and isolated strips of swimbladder contracted in response to sympathomimetics, but this response was prevented after adrenergic blockade. These results suggest the concentration of the swimbladder and associated gas expulsion is under adrenergic control.In untreated fish, an average pressure of 28.1 mm Hg was required to force gas out of the swimbladder through the pneumatic duct. In antropine-treated fish this duct-release pressure fell to an average of 0.2 mm Hg. This suggests constriction of the pneumatic duct is under cholinergic control.Histologically, the pneumatic duct was continuous with the oesophagus and extended as a convoluted duct to the anterior end of the swimbladder. Smooth muscle fibers surrounded the duct along its length and some striated fibers were present at the point where the duct joined the oesophagus. Occlusion of the pneumatic duct may be through the contraction of either of these types of fibers.The term "Gasspuckreflex" as originally used by Franz described the loss of gas from the swimbladder of physostomes in response to decompression. The authors suggest this term be reserved for this passive loss of gas, and not applied to fright-induced gas loss, resulting from active contraction of the bladder wall.

Adrenergic receptors in the swimbladder and gut of a teleost ( Anguilla anguilla)

1. 1. The distribution of α- and β-adrenergic receptor responses in various viscera was investigated by recording of mechanical effects produced by addition of drugs. 2. 2. α and β receptors were demonstrated in the secretory part of the swim bladder by use of adrenergic blocking substances. 3. 3. Isoprenaline contracted the gastric coecum, suggesting presence of α receptors only. 4. 4. In the oesophagus, intestine and pneumatic duct only β receptors were demonstrated. 5. 5. All preparations were contracted by acetylcholine (ACh). Since this effect on the secretory part of the swimbladder was not blocked by phenoxybenzamine —an α receptor blocking substance—ACh probably acts directly and not via activation of adrenergic elements.

マダイ養殖の基礎的研究-IV

In the rearing of artificially hatched Chrysophrys major numerous cases of larval fish with abnormal expansion of the swimbladder were observed between 10 to 15 days after hatching. The oxygen content of the aquarium water in which the larvae were reared was normal (5.1-6.1cc/L). Abnormal expansion of the swimbladder was due to an abnormally large amount of gas in the swimbladder (Figs. 1-3). The long-diameter of the distended swimbladder was about 1/10th of the total length of the body. That of a normal swimbladder is about 1/20th (Table 1). The existence of gas in the swimbladder was recognized in an estimated 40% of the larval fish 9 days after hatching, and in 100% 11 days after hatching. The swimbladder of the young fish up to 8 days after hatching seems to contain sea water in the normal condition. In the larva of Chrysophrys major the development of the gas gland of the swimbladder and the closing of the pneumatic duct occur between 8 to 10 days after hatching (Figs. 9, 10, 12). This period seems to be physiologically insecure for the young fish.

Studies on the Queensland Lungfish, Neoceratodus forsteri (Krefft).

The lung of Neoceratodus forsteri consists of a single elongated sac dorsal to the gut and attached firmly along the dorsal mid-line in the region of the vertebral column. It communicates with the gut through the pneumatic duct which opens ventrolaterally via the glottis, on the right side of the pharynx. The embryological origin of the lung as a ventral outgrowth from the gut is reflected in the marked similarity between their tissues, and in the unusual configuration of the duct and blood vessels. Internally, the lung is divided into compartments formed by septa resulting from infolding of the walls. These compartments are further subdivided to form a spongy alveolar region. In this region of increased surface area run blood capillaries in proximity to the respiratory medium, close enough to allow gaseous exchange with it. Filling the lung is accomplished by a buccal force-pump, as in Amphibia, consisting of the hyoid apparatus and the muscular walls of the buccal cavity. Exhalation of air is effected by contraction of the smooth muscle components of the lung, assisted by its natural elasticity provided by elastin fibres present in both connective tissue and smooth muscle. The structure of the lung, its spongy walls, vascular supply with capillaries close to the air space, open pneumatic duct, regular exchange of air at the surface of the water, and the ability of the fish to survive out of water if kept moist, all point to the function of the lung as a respiratory organ. This is borne out by lung-gas analyses which consistently show lower oxygen level compared with air.