Digestive Tract of La Plata Dolphin, Pontoporia blainvillei

Yamasaki, Fusao; Takahashi, K; Kamiya, Toshiro

doi:10.2535/ofaj1936.52.1_1

Cited by 16 publications

(31 citation statements)

References 4 publications

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“…First, specimens of C. cetaceum did not exhibit signs of degeneration except for senescent worms in the rectum; this indicates that there was no substantial destruction of worms during the time elapsed between host death and necropsy. Second, most C. cetaceum specimens were found firmly attached to the wall of each chamber, such as observed in previous studies (Yamasaki et al, 1974;Brownell, 1975). This strongly suggests that worms likely died in the same chambers where they had lived.…”

Section: Discussionsupporting

confidence: 72%

“…In fact, many stage 1 females were very small and in early sexual development. The release of cystacanths from prey tissues in the MS seems a logical outcome of the digestive physiology of franciscanas; prey are first digested in the MS (Yamasaki et al, 1974) and must be reduced to semifluid chyme at this stage of digestion (Gaskin [1978] and references therein).…”

Section: Discussionmentioning

confidence: 99%

“…1) that terminates at the pyloric stomach, which is a J-shaped, elongated tubular chamber ending with the pyloric sphincter. Histological observations revealed that the connecting channel can be regarded as part of the pyloric stomach (Yamasaki et al, 1974). The stomach is followed by a funnel-shaped structure, the duodenal ampulla that is separated from the intestine proper by a superficial constriction (Yamasaki et al, 1975).…”

Section: Anatomical Description Of Habitatsmentioning

confidence: 99%

“…The upper digestive tract of the franciscana dolphin Pontoporia blainvillei: OE, esophagus; MS, main stomach; CC, connecting channel; PS, pyloric stomach; DA, duodenal ampulla; DP, duodenum proper. Adapted from Yamasaki et al (1974), courtesy of Okajimas Folia Anatomica Japonica.…”

Section: Data Collectionmentioning

confidence: 99%

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Corynosoma cetaceum in the Stomach of Franciscanas, Pontoporia blainvillei (Cetacea): An Exceptional Case of Habitat Selection by an Acanthocephalan

Aznar¹,

Bush²,

Balbuena³

et al. 2001

The Journal of Parasitology

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Adult acanthocephalans are typically found in the intestine of vertebrates, where they can readily absorb nutrients. However, Corynosoma cetaceum has been frequently reported in the stomach of cetaceans from the Southern Hemisphere. The ecological significance of this habitat was investigated by examining data on number, sex ratio, maturity status, biomass, and fecundity of C. cetaceum in different parts of the digestive tract of 44 franciscanas Pontoporia blainvillei. Individual C. cetaceum occurred in the pyloric stomach (PS) and, to lesser degrees, in the duodenal ampulla (DA) and the main stomach (MS). Females outnumbered males in all chambers, although the sex ratio was closer to 1:1 in the MS; there also was a higher proportion of nongravid females, with a smaller biomass in the MS than in the PS and the DA. This evidence suggests that cystacanths are released from prey tissues in the MS, where entire prey are reduced to semi-fluid chyme. The 3 chambers harbored gravid females that did not differ significantly in mean biomass or fecundity. The maturity status of females was nearly identical between the PS and the DA. In the MS, the higher proportion of non-gravid females is probably due to the occurrence of newly recruited females to this site. Mean biomass and fecundity of gravid females covaried strongly and positively among chambers within hosts. These results suggest that there are no major differences between the 3 chambers with respect to the suitability for reproduction by C. cetaceum. However, although the MS is the largest chamber, it harbored the smallest number of gravid females. Interestingly, worms were largely restricted to the aboral portion of the MS, a sheltered region where a concentration of chyme, and thus nutrient availability, likely occurs. Linear distribution differences of gravid female C. cetaceum at increasing intensities suggest that reproductive females occupy chambers according to available space. In summary, the stomach should be considered the main habitat for C. cetaceum. The choice of this habitat is puzzling because other Corynosoma species occur in the intestine, and because the stomach of cetaceans is not an absorptive site.Adult acanthocephalans inhabit the digestive tracts of vertebrates (Crompton, 1973). The preferred site for most species is the intestine (especially the middle region [Petrochenko, 1956]), apparently due to their requirement for simple nutrients that can be absorbed across the body wall (Crompton, 1973;Starling, 1985). However, some species infecting fish have been recorded in the stomach (Petrochenko, 1956), possibly because the stomach of fish is known to be a region of nutrient absorption (Crompton, 1973). Within the groups of acanthocephalans infecting birds and mammals, only 2 species, both in the genus Corynosoma, have been reported as adults from the stomach. Corynosoma hamanni was mostly found in the duodenum of Antarctic seals, but about 3% of the component population was found in the pyloric region of the stomach (Zdzitowiecki, 1...

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Section: Discussionsupporting

confidence: 72%

Section: Discussionmentioning

confidence: 99%

Section: Anatomical Description Of Habitatsmentioning

confidence: 99%

Section: Data Collectionmentioning

confidence: 99%

See 2 more Smart Citations

Corynosoma cetaceum in the Stomach of Franciscanas, Pontoporia blainvillei (Cetacea): An Exceptional Case of Habitat Selection by an Acanthocephalan

Aznar¹,

Bush²,

Balbuena³

et al. 2001

The Journal of Parasitology

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“…All macroscopic parasites seen during the analysis of food remains in the stomachs were collected. Small and large intestines were identified macroscopically according to Yamasaki et al (1975). Based on the methodology used by Andrade (1996), the small intestine was divided into five equal-sized sections and only the first third of each section was sampled.…”

Section: Methodsmentioning

confidence: 99%

Parasites of franciscana (<i>Pontoporia blainvillei</i>) from São Paulo and Paraná States, Brazil

Marigo¹,

Rosas²,

Andrade³

et al. 2002

Lat. Am. J. Aquat. Mamm.

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The franciscana, Pontoporia blainvillei, is a threatened small cetacean of the western South Atlantic Ocean and is commonly caught incidentally in fishing nets along its distribution. Detailed studies regarding parasite loads of P. blainvillei have been recommended as a tool to evaluated ecological segregation and stock structure. We analyzed metazoan parasites from stomach, intestines and lungs of 41 franciscanas from three close geographical areas: Group 1, Guarujá ). The sample consists mainly of immature specimens, less than 3 years old. No parasites were found in the lungs analyzed. The acanthocephalan (Polymorphus sp) found in two stomachs were considered occasional. The trematode Hadwenius pontoporiae (Digenea: Campulidae) was the only parasite found in the intestines with prevalence of 100% for Group 1, 82.35% for Group 2 and 58.33% for Group 3. The mean intensity of H. pontoporiae for Groups 1, 2 and 3 was 39.5, 25.05 and 13.5 parasites per host, respectively. In this study there was a significant difference between the number of parasites among the three groups (Kruskal-Wallis test, p=0.012). Groups 2 and 3 are geographically close, and exhibited non-significant differences in the total number of parasites found (Mann-Whitney test, p=0.063). Groups 1 and 3, that are further apart geographically, differed significantly in the total number of parasites found (Mann-Whitney test, p=0.003). Through the analysis of data from the areas where H. pontoporiae was found [i.e. Areas 1, 2, 3 (this study), Rio Grande do Sul State and Argentina], it could be noticed that the prevalence and mean intensity increase as latitude increases. H. pontoporiae may continue to be useful as a biological tag for identifying franciscanas ecological stocks, together with information from genetic, morphometric and other biological studies. However, it is essential that standardized methodology be used in the collection of the parasite data.Resumo A toninha, Pontoporia blainvillei, é um cetáceo ameaçado do Atlântico Sul Ocidental. Captura acidentais ao longo de sua distribuição são freqüentes. O uso de informações a respeito dos parasitas de P. blainvillei é recomendado para avaliar segregações ecológicas e diferenciar estoques populacionais. Estômagos, pulmões e intestinos de 41 animais foram analisados buscando parasitos metazoários. Os animais são provenientes de 3 áreas geográficas próximas: Grupo 1, Guarujá e Praia Grande ( ). A amostra consiste basicamente de animais imaturos, entre 0 e 3 anos de idade. Nenhum parasito foi encontrado nos pulmões analisados. O acantocéfalo Polymorphus sp, encontrado em dois estômagos foi considerado ocasional. O trematóide Hadwenius pontoporiae (Digenea: Campulidae) foi o único parasito encontrado nos intestinos com prevalência de 100% para o Grupo 1, 82,35% para o Grupo 2 e 58,33% para o Grupo 3. A intensidade média de H. pontoporiae nos Grupos 1, 2 e 3 foi de 39,5; 25,05 e 13,5 parasitos por hospedeiro, respectivamente. Houve uma diferença significativa entre o número de parasitas dos...

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Observations on the anatomy of the stomach and duodenum of the bowhead whale, Balaena mysticetus

et al. 1987

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Gastric and cranial duodenal structure of the bowhead whale (Balaena mysticetus) was examined grossly and microscopically. The stomach was arranged in a series of four compartments. The first chamber, or forestomach, was a large nonglandular sac lined by a keratinized stratified squamous epithelium. It was followed by the fundic chamber, a large, somewhat globular and entirely glandular compartment. At the entrance of the fundic chamber, a narrow cardiac gland region could be defined. The remaining mucosa of the chamber contained the proper gastric glands. A narrow, tubular connecting channel, the third distinct gastric division, was lined by mucous glands and joined the fundic chamber with the final stomach compartment, or pyloric chamber. This fourth chamber was also tubular and lined by mucous glands but was of a diameter considerably larger than the connecting channel. The stomach terminated at the pyloric sphincter which consisted of a well-developed band of circular smooth-muscle bundles effecting a division between the pyloric chamber and small intestine. The small intestine began with the duodenal ampulla, a dilated sac considerably smaller than the fundic chamber of the stomach. The mucosa of this sac contained mucous glands throughout. The ampulla led without a separating sphincter into the duodenum proper which continued the intestine in a much more narrow tubular fashion. The mucosal lining of the duodenum was composed of villi and intestinal crypts. Although their occurrence varied among whales, enteroendocrine cells were identified within the mucous glands of the cardiac region, connecting channel, pyloric chamber, and cranial duodenum. The hepatopancreatic duct entered the wall of the duodenum shortly after the termination of the duodenal ampulla and continued intramurally along the intestine before finally joining the duodenal lumen.

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Digestive Tract of La Plata Dolphin, Pontoporia blainvillei

Cited by 16 publications

References 4 publications

Corynosoma cetaceum in the Stomach of Franciscanas, Pontoporia blainvillei (Cetacea): An Exceptional Case of Habitat Selection by an Acanthocephalan

Corynosoma cetaceum in the Stomach of Franciscanas, Pontoporia blainvillei (Cetacea): An Exceptional Case of Habitat Selection by an Acanthocephalan

Parasites of franciscana (<i>Pontoporia blainvillei</i>) from São Paulo and Paraná States, Brazil

Observations on the anatomy of the stomach and duodenum of the bowhead whale, Balaena mysticetus

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