Regulation of ventilation in the caiman (Caiman latirostris): effects of inspired CO2 on pulmonary and upper airway chemoreceptors

In order to study the relative roles of receptors in the upper airways, lungs and systemic circulation in modulating the ventilatory response of caiman (Caiman latirostris) to inhaled CO2, gas mixtures of varying concentrations of CO2 Were administered to animals breathing through an intact respiratory system, via a tracheal cannula by-passing the upper airways (before and after vagotomy), or via a cannula delivering gas to the upper airways alone. While increasing levels of hypercarbia led to a progressive increase in tidal volume in animals with intact respiratory systems (Series 1), breathing frequency did not change until the CO2 level reached 7%, at which time it decreased. Despite this, at the higher levels of hypercarbia, the net effect was a large and progressive increase in total ventilation. There were no associated changes in heart rate or arterial blood pressure. on return to air, there was an immediate change in breathing pattern; breathing frequency increased above air-breathing values, roughly to the same maximum level regardless of the level of CO2 the animal had been previously breathing, and tidal volume returned rapidly toward resting (baseline) values. Total ventilation slowly returned to air breathing values. Administration of CO2 via different routes indicated that inhaled CO2 acted at both upper airway and pulmonary CO2-sensitive receptors to modify breathing pattern without inhibiting breathing overall. Our data suggest that in caiman, high levels of inspired CO2 promote slow, deep breathing. This will decrease deadspace ventilation and may reduce stratification in the saccular portions of the lung.

Baroreflex control of heart rate in the broad-nosed caiman Caiman latirostris is temperature dependent

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

AN ULTRASTRUCTURAL-STUDY ON THE ENDOCRINE PANCREAS OF CAIMAN-LATIROSTRIS, WITH SPECIAL REFERENCE TO PANCREATIC MOTILIN CELLS

Pancreatic endocrine cells of Caiman latirostris were investigated by electron microscopy using conventional and immunocytochemical methods. Ultrastructurally, four types of endocrine cells were classified according to the morphology of their secretory granules. Three types of endocrine cells were identified as either glucagon, insulin or somatostatin cells by the presence of such characteristic granules well established in mammals. The remaining endocrine cell type could not be classified by its ultrastructural features alone.Immunocytochemical observations confirmed the ultrastructural classification of glucagon, insulin and somatostatin cells. In addition, endocrine cells immunoreactive for either pancreatic polypeptide (PP) or motilin were identified. Morphometric analysis of PP- and motilin-immunoreactive granules demonstrated that they were the most polymorphous and smallest granules among the pancreatic endocrine cell granules. Although both PP and motilin granules closely resemble each other, motilin granules were smaller in size and more spherical in shape than PP granules.

KARYOTYPIC ANALYSIS AND CHROMOSOME BIOMETRY OF CELL-CULTURES OF THE YELLOW-THROATED ALLIGATOR (CAIMAN-LATIROSTRIS DAUDIN)

Blood from eight specimens of both sexes of the alligator Caiman latirostris was collected and incubated in culture medium. Conventional as well as chromosomal banding (C and NOR) techniques were used.The diploid number was determined as 42, being 24 telocentric, 12 metacentric and six submetacentric, with real lengths varying from 1.49 to 6.08, 1.63 to 3.71, and 2.41 to 3.19 mum, respectively. The fundamental number was 60. About 81% of the chromosomes were small and 19% medium in size. NOR-banding was presented for the first time for this species and it was verified that only one submetacentric pair (no. 20) was marked on arm q, and under conventional staining it presented a secondary constriction. There was no association between NOR marked chromosomes.

A fatal attack on a child by a black caiman (Melanosuchus niger)

We describe a fatal attack by a black caiman (Melanosuchus niger) on an 11-year-old child with comments on the reptile's aggression mechanisms and the conditions under which this kind of incident takes place in the Amazon region. © 2011 Wilderness Medical Society.

Avaliação de propriedades criadoras do jacaré-de-papo-amarelo (Caiman latirostris: Alligatoridae) do Estado de São Paulo

Pós-graduação em Aquicultura - FCAV

Isotopic Discrimination Factors (Delta C-13 and Delta N-15) between Tissues and Diet of the Broad-Snouted Caiman (Caiman latirostris)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Das amerikanische Krokodil (Crocodilus americanus Laur.) in Freiheit und Gefangenschaft

Von Jos. Scherer

Estado sanitário do jacaré-de-papo-amarelo (Caiman latirostris) em paisagens antropizadas no Estado de São Paulo

O jacaré-de-papo (Caiman latirostris) é considerado um crocodiliano de médio porte que apresenta uma ampla distribuição latitudinal na América do Sul. Possivelmente a espécie possui a situação mais complexa entre os crocodilianos brasileiros quanto ao aspecto da conservação, basicamente porque suas populações encontram-se fragmentadas em grande parte de sua área de distribuição original e por utilizarem áreas com fortes atividades antrópicas. Embora a espécie possua aparentemente um processo adaptativo frente a estas pressões, um aspecto fisiológico pode ainda sofrer rápida alteração quando submetido a elas: o estado sanitário. Desta maneira, este estudo objetivou determinar o estado sanitário do maior predador aquático, utilizando duas áreas distintas no Estado de São Paulo, através da determinação dos perfis hematológicos e bioquímicos do sangue, além da caracterização da microbiota oral, servindo de modelo à conservação da espécie em ambientes alterados. No primeiro capítulo foram determinados o perfil hematológico e bioquímico do sangue utilizando-se 29 indivíduos (19 machos e 10 fêmeas) capturados em Angatuba e 11 indivíduos (2 machos, 4 fêmeas e 5 filhotes) capturados em Cubatão. Diferenças estatísticas significativas foram encontradas nos valores de creatinina na comparação entre fêmeas de ambas as áreas de estudo (p = 0,033) e nos valores de alanina aminotransferase (p = 0,003), hemácias (p = 0,034), hemoglobina (p = 0,049) e volume corpuscular médio (p = 0,027) quando da comparação entre sexos. No segundo capítulo determinou-se a microbiota oral destes animais através do isolamento, identificação e caracterização bacteriana, em conjunto com o teste de perfil de susceptibilidade aos antimicrobianos. Foram determinados 14 diferentes tipos de bactérias na área de Angatuba, sendo uma classificada como baciliforme aeróbio Gram-positivo, uma como bacilo Gram-negativo e 12 classificadas como Enterobactérias Gram-negativas. Na área de Cubatão foram isolados cinco tipos de bactérias, sendo quatro classificadas como Enterobactérias Gram-negativas e uma como baciliforme aeróbio Gram-positivo. Considerando que o uso de antimicrobianos é um processo primário no tratamento de animais e pessoas, principalmente nos casos que envolvam infecções provocadas pela interação homem x animais, para ambas as áreas de estudo, as quinolonas Enrofloxacina e Norfloxacina, além do aminoglicosídeo Gentamicina, foram os antimicrobianos que apresentaram os menores índices de resistência frente aos isolados testados.

Physiological and morphological responses to feeding in broad-nosed caiman (Caiman latirostris)

Broad nosed caiman are ectotherm sauropsids that naturally experience long fasting intervals. We have studied the postprandial responses by measuring oxygen consumption using respirometry, the size changes of the duodenum, the distal small intestine, and the liver, using repeated non-invasive ultrasonography, and by investigating structural changes on the level of tissues and cells by using light- and electron microscopy. The caimans showed the same rapid and reversible changes of organ size and identical histological features, down to the ultrastructure level, as previously described for other ectothermic sauropsids. We found a configuration change of the mucosa epithelium from pseudostratified during fasting to single layered during digestion, in association with hypertrophy of enterocytes by loading them with lipid droplets. Similar patterns were also found for the hepatocytes of the liver. By placing the results of our study in comparative relationship and by utilizing the phylogenetic bracket of crocodiles, birds and squamates, we suggest that the observed features are plesiomorphic characters of sauropsids. By extending the comparison to anurans, we suggest that morphological and physiological adjustments to feeding and fasting described here may have been a character of early tetrapods. In conclusion, we suggest that the ability to tolerate long fasting intervals and then swallow a single large meal as described for many sit-an-wait foraging sauropsids is a functional feature that was already present in ancestral tetrapods.

Crocodile industry in Uganda

The foregoing account gives a picture of the exploitation and control of the wild population of Crocodilus niloticus in Uganda from 1920 to the present day. The economic value of the crocodile is shown, and some idea is given of the possibility of maintaining this economic return to Uganda by farming crocodiles in captivity. The Uganda Fisheries Department is actively pursuing the issues which arise from the present status of the wild population, and the need for artificial rearing of crocodiles.

我国湾鳄生活史源考述

<正> 鳄类起源在白垩纪从中鳄类产生出两支鳄类,一支是南美的西贝鳄;另一支就是真鳄即现代鳄。我国的湾鳄(Crocodilus porosus Schneider),属真鳄亚目Eusuchia、鳄科Crocodilidae;因而,它不像扬子鳄(Alligalot Sinensis Fauvel)广布于长江中下游区域,而是仅限于我国南部沿海及印度与马来半岛。湾鳄属真鳄类,它主要栖息于热带和亚热带,这也不同于扬子鳄仅限于生活在温带地区所特