Atlantic bluefin tuna Thunnus thynnus feeding ecology in the northern Gulf of Mexico: a preliminary description of diet from the western Atlantic spawning grounds.

A combination of stomach contents, nitrogen stable-isotope and tissue C:N values are presented to demonstrate feeding activity of Atlantic bluefin tuna Thunnus thynnus on the Gulf of Mexico (GOMEX) spawning grounds. Diets include teleosts, cephalopods, crustaceans and a pelagic tunicate (Pyrosoma atlanticum). Results reveal the need to classify the GOMEX as a T. thynnus feeding ground.

Gluten-dependent antibodies in horses with inflammatory small bowel disease (ISBD).

BACKGROUND: Equine inflammatory small bowel disease (ISBD) is an idiopathic pathologic condition seeming to increase in prevalence. OBJECTIVE: To investigate the potential role of gluten in equine ISBD. ANIMALS & METHODS: Antibodies known to be important in the diagnosis of human coeliac disease (CD): IgA antibodies to human recombinant and guinea pig tissue-transglutaminase (TGA), native gliadin (AGA), deamidated-gliadin-peptides (DGPA), and primate and equine endomysium (EMA) were assessed in blood samples from three different groups of horses: ISBD affected (n = 12) on a gluten-rich diet and controls either on gluten-rich (n = 22) or gluten-poor (n = 25) diets. Significant differences (p < 0.05) between groups were assessed using the Wilcoxon test. RESULTS: Both ISBD-affected horses and gluten-rich controls had significantly (p < 0.0004) higher hrTGA titers than gluten-poor controls. However, ISBD horses did not show significantly increased levels of any of the CD related antibodies when compared to gluten-rich controls. Nevertheless, markedly increased antibody levels (TGA, EMA and DGPA) were found in one of the ISBD horses. The introduction of a gluten-free ration in this 14-year-old warmblood stallion resulted after 6 months in the reduction of antibody levels and clinical recovery associated with improved duodenal histopathology. CONCLUSION: To the best of our knowledge, this is the first study assessing gluten-related antibodies in horses and results suggest a potential pathogenic role of gluten in at least some cases of equine ISBD. Clinical importance and impact for human medicine: Given serology and concurrent clinical findings, this study warrants further investigations into the immunologic basis of possible gluten-sensitive enteropathy in horses and analogy with human disease.

Lawsonia intracellularis-associated proliferative enteritis in weanling foals in the Netherlands.

Equine proliferative enteropathy (EPE) is an emerging infectious enteric disease caused by the obligate intracellular gram-negative bacterium Lawsonia intracellularis. EPE was tentatively diagnosed in six weanling foals, aged between 5 and 7 months. Clinical signs included depression, anorexia, ventral oedema, and weight loss. Plasma biochemistry consistently revealed severe hypoproteinaemia. The ante-mortem diagnosis of EPE was based on clinical signs, hypoproteinaemia (6/6), the detection of moderate-to-high titres of L. intracellularis antibody (6/6), and severe thickening of the small intestinal wall on ultrasonography (2/2), or L. intracellularis detected in faeces by PCR (I/2). The first foal died despite treatment and at post-mortem examination the tentative diagnosis was EPE. Three foals from the same farm, which showed similar clinical symptoms were treated with azithromycin and rifampicin; two survived. Post-mortem examination of the foal that died confirmed the tentative clinical diagnosis of EPE on the basis of the lesions found and the detection of L. intracellularis--DNA in the ileum and jejunum. The fifth foal died despite intensive treatment and the post-mortem examination revealed lymphohistiocytic enteritis, typhlitis, and widespread thrombosis in several organs. The sixth foal recovered completely after treatment. This report confirms the presence of clinical L. intracellularis infection in weanling foals in the Netherlands and shows the difficulty in reaching a definitive ante-mortem diagnosis.

Repeated high dose imidocarb dipropionate treatment did not eliminate Babesia caballi from naturally infected horses as determined by PCR-reverse line blot hybridization.

Imidocarb treatment of horses infected with Babesia caballi is supposed to eliminate the infection, but data on the efficacy of this treatment is scarce. The study presented here concerns four Paso Fino horses, which were imported into the island of Curacao on the basis of a piroplasmosis negative complement fixation test (CFT). Upon re-testing with an indirect fluorescent antibody test immediately after arrival in Curacao, two horses appeared to have antibodies to B. caballi and all horses had antibodies to Theileria equi. Subsequent testing with polymerase chain reaction combined with a reverse line blot yielded positive results for both agents in all four horses. Treatment with five consecutive doses of imidocarb dipropionate (4.7 mg/kg BW im q 72 h), temporarily resulted in negative results, but B. caballi and T. equi were detected again in the samples taken at 6 and 18 weeks after completion of the treatment. These results confirm that the CFT is not a suitable test for pre-import testing and that even high dose treatment with imidocarb may not be capable of eliminating B. caballi and T. equi infections from healthy carriers.

The Fell pony immunodeficiency syndrome also occurs in the Netherlands: a review and six cases.

Over the last ten years a fatal syndrome associated with immunodeficiency and severe anaemia has been reported in young Fell pony foals in the UK. Affected foals are usually normal at birth but from the age of 2-4 weeks they progressively lose condition and become severely anaemic. Signs of immunodeficiency become apparent at around 3-4 weeks of age. Morbidity is low but mortality is 100% despite intensive treatment. Affected foals die or are euthanized usually before they reach the age of 3 months. A single autosomal recessive gene is suggested to be on the basis of the syndrome. Recently, affected Fell pony foals have been identified in the Netherlands and between June 2003 and August 2005, six affected Fell pony foals were referred to the Faculty of Veterinary Medicine for investigation.

[A literature review of equine piroplasmosis after an episode of acute babesiosis in a Dutch Standardbred foal after a stay in Normandy]. / Een literatuuroverzicht van equine piroplasmose naar aanleiding van acute babesiose bij een Nederlands draverveulen na verblijfin Normandië.

Piroplasmosis, a disease endemic to most tropical and subtropical areas, appears to be spreading to more temperate zones. This article gives a review of equine piroplasmosis and describes an acute case of infection with Babesia caballi in a Dutch Standard bred foal after a short stay at a stud in Normandy (France). A 3-month-old stallion foal was presented with lethargy, fever of 41 degrees C, and pale mucosal membranes. Haematology revealed a low packed cell volume (14 l/l) leucytosis (25 G/l) and a high blood urea nitrogen concentration (20.1mmol/l). Infection with B. caballi was diagnosed on the basis of Giemsa staining blood smears and was confirmed by polymerase chain reaction in combination with RLB. Treatment with imidocarb dipropionate and a blood transfusion resolved the haemolytic crisis.

Borrelia burgdorferi infections with special reference to horses. A review.

This review discusses the literature on B. burgdorferi infections in view of the rising incidence of this infection in general and the increasing concerns of horse owners and equine practitioners. Lyme disease, the clinical expression of Borrelia infections in man is an important health problem. The geographic distribution of B. burgdorferi infections in equidae should resemble that of human cases because the vector tick involved, Ixodes ricinus, feeds on both species and, indeed, the infection has been established many times in horses. However, a definite diagnosis of the disease "Lyme borreliosis" in human beings as well as in horses and other animals is often difficult to accomplish. Although a broad spectrum of clinical signs has been attributed to B. burgdorferi infections in horses, indisputable cases of equine Lyme borreliosis are extremely rare so far, if they exist at all.

[Incarcerated umbilical hernia in the horse: a case with a review of the literature]. / Hernia umbilicalis incarcerata bij het paard, een literatuuroverzicht aan de hand van een casus.

Umbilical hernias are common in foals. This article provides a review of the literature and presents a case of an 1.5-year-old Friesian mare with an incarcerated umbilical hernia. After reposition of the incarcerated intestine (with a lot of effort), the practising veterinarian referred the mare to the Department of Equine Sciences. Preperforative peritonitis was diagnosed, presumed to be caused by necrotic bowel. After laparotomy, this tentative diagnosis was confirmed. The necrotic part of the small intestine was resected and intensive medical treatment was started. Initially, the mare recovered well, but seven days after surgery her general condition deteriorated and she had to be euthanized. At necropsy, impaction of the stomach and rupture of the stomach wall were found. The impaction was probably a result of the generalized peritonitis.

Development of the penis and clitoris in the tammar wallaby, Macropus eugenii.

The development of the phallus from the indifferent stage to sexual dimorphism has not been described in any marsupial. This study describes the morphological and histological changes occurring in the development of the phallus of the tammar wallaby. The development of the penis and clitoris in the tammar closely follow the most widely accepted model for the development of the same organs in eutherian mammals. The urogenital plate that is present in both sexes at birth hollows out to form a urogenital groove at approximately 70 days postpartum (p.p.). There is then greater growth of the phallus in males than in females, which results in sexual dimorphism in length approximately 100 days p.p. In males, the urogenital groove secondarily closes over at this time and fuses in the midline and by 128 days p.p. the penile urethra is fully formed. In females, the groove remains open. The clitoris changes little morphologically from the time of formation of the urogenital groove until adulthood. The pattern of development of the penis in the tammar is similar to that seen in eutherian mammals. There is strong evidence that penis development is androgen-dependent in the tammar, yet unusually it becomes sexually dimorphic at a time when androgen content of the developing testis is low.

Developmental expression of the androgen receptor during virilization of the urogenital system of a marsupial.

In the marsupial tammar wallaby, virilization begins approximately 3 wk after the onset of testosterone synthesis. In the eutherian mammal, in contrast, the onset of virilization of the male urogenital tract occurs shortly after the onset of androgen synthesis. Androgen action requires the presence of the androgen receptor to mediate a response in target tissues. We therefore investigated the developmental expression of the androgen receptor (AR) in both sexes of the tammar wallaby. AR gene transcript was detected in fetal gonad and brain as early as Day 19 of the 26.5-day gestation, 7 days earlier than the first rise in testicular testosterone (Days 0-5 postpartum [p.p.]). Immunoreactive AR was identified in the male urogenital sinus (UGS) 2 days before birth and in the female UGS and mammary glands by the day of birth. AR was present in the UGS, vagina, and prostate until Day 152 p.p., the oldest age examined. AR was identified in the gubernaculum testis at Day 2 p.p. and became more abundant by Day 32. In the phallus of both sexes, AR was identified by Day 4 p.p. and until Day 157, the oldest age examined. AR was not detected in the scrotum at any age from the day of birth to Day 157. Maturation of the phallus, wolffian duct, and epididymis was marked by appearance of epithelial immunostaining. AR was localized in the epithelium of the UGS in females by Day 50 p.p. but was not found in the epithelium of the male UGS up to Day 152 p.p., the oldest examined. AR were found in the mesenchyme of the UGS of male and female tammars 3-4 wk before virilization is first evident in the male at Day 25 p.p. We conclude that the presence of AR is not the initiating signal for virilization of the UGS in this marsupial male.

The influence of the anti-androgen flutamide on early sexual differentiation of the marsupial male.

The development of the prostate and the normal descent of the testes in the tammar wallaby (Macropus eugenii) were influenced by treatment with the non-steroidal anti-androgen flutamide. Male pouch young were treated daily from day 9 to day 45, or from day 20 to day 45, of pouch life. Prostate development was inhibited in both treatment groups to a similar extent. Since prostatic buds do not form until day 25 of pouch life, these results suggest that there is a window of androgen sensitivity operating between day 20 and day 25 of pouch life. The number of prostatic buds was significantly lower, but despite the duration of treatment there was never complete abolition of prostate development. Although testes had descended to the same position in treated and control pouch young, inguinal hernias developed in three of four animals treated with flutamide from day 9. These data demonstrate that virilization of the male reproductive tract in this marsupial is dependent on a relatively brief exposure to androgens. Blocking androgen receptor action interferes with normal development of the inguinal canal, which suggests that it is this aspect of inguinoscrotal testicular descent that is androgen dependent.

Effects of a 5 alpha-reductase inhibitor, finasteride, on the developing prostate and testis of a marsupial.

This study examines the role of dihydrotestosterone in virilization of the developing male tammar. The onset of prostate differentiation in this marsupial species normally occurs around 25 days postpartum, long after the onset of testicular testosterone production immediately after birth and the appearance of 5 alpha-reductase in the urogenital sinus before day 10. Males treated with the 5 alpha-reductase inhibitor Finasteride had reduced prostatic growth and development, and their testicular structure was disorganized. Exogenous testosterone in males enhanced the development of prostatic buds but also caused damage to the testis structure. Treatment of female tammars with testosterone between days 20-30 postpartum stimulated prostatic tissue formation and Wolffian duct development, confirming that prostatic differentiation is initiated by androgens and occurs over a relatively narrow window of time. Testosterone had a deleterious effect on the ovary, destroying the germ cells. Although treatment with testosterone damaged gonadal cellular structure in both male and female tammar young, dihydrotestosterone is apparently necessary for stability of the seminiferous tubules in the testis. Taken together, these results suggest that dihydrotostesterone initiates prostatic development between days 20 and 25 after birth in this marsupial.