Clostridium perfringens as the cause of death of a captive Atlantic bottlenosed dolphin (Tursiops truncatus)

A previously healthy captive female bottlenosed dolphin (Tursiops truncatus) died suddenly. At necropsy, Clostridium perfringens was isolated from dorsal muscle, blood, left heart ventricle, thoracic fluid, and abdominal fluid. An identical strain was recovered from pool water. A male dolphin in the same pool had inflicted several "rake" marks on the dorsal surface of the female. Water-borne bacteria probably entered these lesions which served as the focus for anaerobe penetration and spread.     

Lymphangiomyomatosis in the Atlantic bottlenose dolphin (Tursiops truncatus).

The first case of lymphangiomyomatosis in a marine mammal is reported from a stranded male Atlantic bottlenose dolphin (Tursiops truncatus). This progressive proliferative disease involved the lungs and the mediastinal and probably mesenteric lymph nodes. An extraordinarily low level of testosterone may have been pathologically significant since all reported cases of this disease in humans occur in females.     

MHC class II molecules and immunoglobulins on peripheral blood lymphocytes of the bottlenosed dolphin, Tursiops truncatus.

The immune system of marine mammals is of comparative interest because of its adaptation to the aquatic environment. Little information, however, is available on its cellular and molecular components. Here, we used a cross-reactive antibody to MHC class II molecules and an immunoglobulin-specific antiserum for identifying these molecular species on lymphocytes of the bottlenosed dolphin, Tursiops truncatus. Limited structural analyses indicated that class II molecules and immunoglobulins of dolphin closely resemble those of other vertebrates. In the peripheral blood of most land mammals both class II and immunoglobulins are usually found on B but not T lymphocytes. Expression of immunoglobulins on dolphin peripheral blood lymphocytes suggests a ratio of B cells to T cells comparable to that of land mammals. However, unlike the majority of land mammals, virtually 100% of the peripheral T cells display pronounced expression of class II molecules, generally considered an indication of T cell activation. It is therefore possible that the physiology of T cell activation has unusual attributes in the dolphin. It is especially interesting that some land mammals, namely swine (ungulates) and dogs and cats (carnivores), also express class II molecules on peripheral blood T lymphocytes. Since ungulates and carnivores are thought to share a common distant ancestry with toothed whales, the evolutionary history may be more relevant than the environmental history in determining these unusual attributes.     

Orbital gland structure and secretions in the Atlantic bottlenose dolphin (Tursiops truncatus)

Orbital gland structure of the Atlantic bottlenose dolphin, Tursiops truncatus, was examined at the macroscopic, light microscopic, and electron microscopic levels. The gland completely encircles the ocular globe in a belt-like fashion near the conjunctival fornix but is considerably more developed medially. Duct openings are scattered throughout the fornix and over the surface of the palpebral conjunctiva. Microscopically, the gland has a tubuloalveolar arrangement; alveolar cells contain numerous secretory vesicles which can be interpreted as two structural types by light and electron microscopy. Histochemical staining demonstrates that both types contain glycosaminoglycans. Lipid analysis of the glandular secretion (dolphin tears) shows them to be non-oily and to contain only negligible amounts of cholesterol, triglycerides, phospholipids, and free fatty acids. The secretion is clear, slippery, and viscoelastic and well-adapted to protecting the eye and to reducing frictional forces between the eye surface and surrounding seawater.     

Association between burst-pulse sounds and aggressive behavior in captive Atlantic bottlenosed dolphins (Tursiops truncatus)

A specific display observed during agonistic behavior among captive Atlantic bottlenosed dolphins (Tursiops truncatus) was examined. The primary component of the display was an open-mouthed posture accompanied by violent vertical head motions and the emission of pulse-type vocalizations. Jaw-clap behavior produced during the display was quantified for use as an index of aggressive motivation. By aurally monitoring the animals' vocalizations it was found that the level of aggressive response between the participants of the interactions increased with the production and subsequent duration of burst-pulse sounds. The possibility of burstpulse sounds resulting in auditory or tactile discomfort when directed toward conspecifics is discussed.     

The Immunoglobulin G Heavy Chain (IGHG) genes of the Atlantic bottlenose dolphin, Tursiops truncatus

Dolphin Immunoglobulin G Heavy Chain (IGHG) sequences were obtained by PCR amplification of cDNA from peripheral blood leukocytes using degenerate primers. Analysis of full-length sequences indicated the presence of two expressed isotypes, IGHG1 and IGHG2 that differ mainly in the hinge region of the molecule. Genomic Southern blot analysis indicated that the IGHG1 and IGHG2 genes are most likely present in single copies. The inferred amino acid sequences show greatest similarity between the dolphin and other closely related artiodactyl species. The genetic structure of the IGHG genes were deduced through genomic PCR and revealed that the hinge regions of both IGHG1 and IGHG2 are encoded by a single exon. The transmembrane region of the dolphin IGHG chain shows similarity to the transmembrane region of other mammalian IGHG chains with a canonical CART motif. This is in contrast to the unusual Ser to Gly substitution previously found in the dolphin IGHM transmembrane region, and the functional significance of this variation for B cell antigen-receptor dimer activation remains unknown.     

Vertebral osteomyelitis and suspected diskospondylitis in an Atlantic bottlenose dolphin (Tursiops truncatus)

A 21-yr-old male Atlantic bottlenose dolphin (Tursiops truncatus) was performing at an aquatic park when it developed a soft tissue swelling anterior to the flukes. Subsequent radiographic evaluation revealed the animal to have vertebral osteomyelitis and suspected diskospondylitis. The case was successfully managed with long-term antibiotic therapy.     

Comparative milk composition of the bottlenosed dolphin (Tursiops truncatus), humpback dolphin (Sousa plumbea) and common dolphin (Delphinus delphis) from southern African waters

1. Gross compositional data for milk samples of Tursiops truncatus, Sousa plumbea and Delphinus delphis are presented and compared with existing cetacean milk values. 2. Two factors appear to govern fat content and calorific value of the milk: (a) habitat, and (b) the stage of lactation. 3. Delphinus milk is unusual in that it has a higher P than Ca content. 4. The Fe content in cetacean milk is higher than that for terrestrial mammals and may be related to improved O2 binding requirements.     

Progress report: Results of a long-range captive breeding program for the bottlenose dolphin,Tursiops truncatus and Tursiops truncatus gilli

There have been 36 bottlenose dolphins born in breeding colonies at Sea World, California, and Sea World, Florida, from 1978–1985. Significant features of this successful reproductive program are construction of a compatible breeding colony, early hormonal detection of pregnancy, pre- and postnatal association of inexperienced mothers with experienced females and their calves, and minimized handling of the mothers and calves until the calves are over 1 year of age. Inclusion in the breeding colonies of males old enough to be effective breeders is stressed. Females in the colonies have successfully bred from 8–9 years of age to 23–24 years of age. Calving intervals in the colonies vary from 2 to over 3 years. Calves are born all year round, with some peaking in calving activity in the spring and fall months. Serum progesterone levels greater than 6,000 pg/ml, maintained over a 4–6-week period, are considered indicative of pregnancy. Progesterone levels vary from less than 10,000 to over 50,000 pg/ml during gestation, averaging 25,000 pg/ml. The need for further study of variation in the pattern of progesterone levels during pregnancy is emphasized. A gestation period for Tursiops of 11.5 to 12 months is consistent with our cumulative progesterone data.     

Behaviorally measured tactile sensitivity in the common bottlenose dolphin,Tursiops truncatus

Little research has been conducted on the somatosensory system of toothed whales and it remains uncertain how tactile sensitivity varies about their bodies. In this study, tactile sensitivity to high-frequency (250-Hz) displacement of the skin was quantified in three trained adult common bottlenose dolphins (Tursiops truncatus) using a vibratory device (tactor). The magnitude of skin displacement was controlled by varying the voltage to the tactor held against the skin surface with a constant force. Tactile thresholds were determined using an adaptive method of limits in which dolphins reported perception of the tactile stimulus by producing a whistle. Displacement thresholds ranged from 2.4 to 40 μm, with the greatest sensitivity found along the rostrum, melon, and blowhole. Sensitivity decreased caudally along the body, with the dorsal fin and tip of the fluke being the least sensitive locations tested. The results support hypotheses that the follicles on the dolphin rostrum are particularly important for perception. The reduction in tactile sensitivity at the appendages is consistent with their primary role in stabilization and locomotion compared to exploration or environmental sensing.     

Assessment of increased serum aminotransferases in a managed Atlantic bottlenose dolphin (Tursiops truncatus) population

Nonspecific chronic hepatitis and increased activities of serum aminotransferases have been reported in cetaceans (dolphins, porpoises, and whales). We identified bottlenose dolphins in our current population with episodic increases in serum aminotransferases, specifically alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and we hypothesized that hematologic and serum biochemical changes in these animals may provide clues as to potential causes of liver disease in cetaceans. A retrospective case-control study involving 1,288 blood samples collected during 1998-2006 from 18 dolphins (six cases and 12 age- and sex-matched healthy controls) was conducted to compare eosinophil and platelet counts; and serum proteins, albumin, globulins, bilirubin, gamma glutamyltransferase (GGT), cholesterol, triglycerides, glucose, iron, and erythrocyte sedimentation rates. Bottlenose dolphins with increased ALT and AST activities were more likely to have higher serum globulins, bilirubin, GGT, iron, glucose, triglycerides, and cholesterol levels, greater erythrocyte sedimentation rates, and lower platelet counts compared to healthy controls. Our findings suggest that dolphins with chronic increases in aminotransferases may have a chronic hepatitis involving iron overload with similar etiologies and pathophysiology compared to terrestrial mammals. Areas for future research include predisposing metabolic risk factors; associations between iron overload and a diabetes-like condition; and a potential overlap syndrome involving autoimmune responses that may or may not be associated with viral infection.     

Chemical nature of lachrymal products in the dolphin Tursiops truncatus]

Studies have been made on carbohydrate-protein complex (the ratio of carbohydrate to protein is equal to 1 : 2) in lachrymal products of the dolphin. It was shown that protein component includes 14 amino acids, in which diamino monocarboxylic acids amount to 58%. The ratio of the latter to monoamino dicarboxylic acids is equal to 4.3. Therefore the proteins of lachrymal products are basic ones. This peculiarity of the proteins and the absence of cystein and tryptophan in them indicate that these proteins are represented by histon-like ones, which exhibit high capacity to complex formation. It was demonstrated histochemically, that carbohydrate component of lachrymal reproduct is represented by chondroitin-sulfate B. By thin layer chromatography, neutral monosaccharides (galactose and fucose) were detected, which presumably constitute terminal links of the prosthetic groups.     

Ultrasonographic imaging of the testis and epididymis of the bottlenose dolphin, Tursiops truncatus aduncas

Eight male bottlenose dolphins, Tursiops truncatus aduncas, underwent examination of the reproductive organs to investigate the use of real-time B-mode ultrasonography in assessment of reproductive status and to establish normal ultrasonographic appearances. Ultrasonography allowed repeatable examinations which were well tolerated by all animals. Ultrasonography was used to examine the testes, epididymides, vasa deferentia, penis, bulbourethral and bulbocavernosal muscles; the prostate was not convincingly distinguished from surrounding muscles. Testicular echopatterns and size differed among individuals. Three distinct testicular echopatterns were discerned and could be used to differentiate males of different reproductive status. Ultrasonographic appearance of the testes provides useful data in assessing the reproductive status of male dolphins.     

Comparative characteristics of the spatial hearing in the dolphin, Tursiops truncatus, and in man

The paper presents data on the directional selectivity of hearing in the bottlenose dolphin as a function of masking noise angle. It has been shown that the hearing system of dolphins is characterised by sharp lowering of masked thresholds depending on the noise going in the high frequency region. The same effect is shown in man, but not so evidently.