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Marco M.V.P.,Proyecto Yacare Laboratorio Of Zoologia Aplicada Anexo Vertebrados | Marco M.V.P.,CONICET | Pina C.I.,Proyecto Yacare Laboratorio Of Zoologia Aplicada Anexo Vertebrados | Pina C.I.,CONICET | And 5 more authors.
Zoological Studies | Year: 2010

Different studies found that incubation temperature has an influence on the size of Caiman latirostris hatchlings and determines their gonadal sex. Experimental manipulations revealed that the effects of temperature on growth are independent of sex. Ambient temperature after hatching is also an influential factor: juvenile caiman had lower growth at a cool (29°C) vs. a warm temperature (33°C) independent of incubation temperatures. Two-month-old caiman were raised at 2 different temperatures (29 and 33°C) for 100 d. These animals were subjected to different incubation treatments: 29, 31 (females), 33 (males), and 33°C with 17β-estradiol (females). No differences were found in growth based on incubation temperature or sex. Our data indicate that the evolutionary advantage of a temperature-dependent sex determination, if it exists, is not bound to differential growth between the sexes nor to incubation temperature, at least in the 1st stages of life before hatchlings reach their 1st winter. Temperatures during the development and grow-out phases have direct effects on the size of the broad-snouted caiman.

Poletta G.L.,National University of Santa | Poletta G.L.,Proyecto Yacare Laboratorio Of Zoologia Aplicada Anexo Vertebrados | Poletta G.L.,CONICET | Simoniello M.F.,National University of Santa | Mudry M.D.,CONICET
Comparative Biochemistry and Physiology Part - C: Toxicology and Pharmacology | Year: 2016

Several xenobiotics, and among them pesticides, can produce oxidative stress, providing a mechanistic basis for their observed toxicity. Chronic oxidative stress induces deleterious modifications to DNA, lipids and proteins that are used as effective biomarkers to study pollutant-mediated oxidative stress. No previous report existed on the application of oxidative damage and antioxidant defense biomarkers in Caiman latirostris blood, while few studies reported in other crocodilians were done in organs or muscles of dead animals. The aim of this study was to characterize a new set of oxidative stress biomarkers in C. latirostris blood, through the modification of conventional techniques: 1) damage to lipids by thiobarbituric acid reactive substances (TBARS), 2) damage to DNA by comet assay modified with the enzymes FPG and Endo III, and 3) antioxidant defenses: catalase, superoxide dismutase and glutathione; in order to apply them in future biomonitoring studies. We successfully adapted standard procedures for CAT, SOD, GSH and TBARS determination in C. latirostris blood. Calibration curves for FPG and Endo III showed that the three dilutions tested were appropriate to conduct the modified comet assay for the detection of oxidized bases in C. latirostris erythrocytes. One hour of incubation allowed a complete repair of the damage generated. The incorporation of these biomarkers in biomonitoring studies of caiman populations exposed to xenobiotics is highly important considering that this species has recovered from a serious endangered state through the implementation of sustainable use programs in Argentina, and represents nowadays a relevant economic resource for many human communities. © 2015 Elsevier Inc.

Latorre M.A.,Proyecto Yacare Laboratorio Of Zoologia Aplicada Anexo Vertebrados | Latorre M.A.,CONICET | Lopez Gonzalez E.C.,Proyecto Yacare Laboratorio Of Zoologia Aplicada Anexo Vertebrados | Lopez Gonzalez E.C.,CONICET | And 4 more authors.
Acta Herpetologica | Year: 2015

The present study aimed to evaluate basal frequency of micronuclei (MN) and hematological values in adult Phrynops hilarii in order to propose this aquatic turtle, broadly distributed in our region, as a biological monitor for future studies of environmental pollution assessment. Thirty-two adult turtles from a semi-natural environment locat­ed at the Zoological Experimental Station (Santa Fe, Argentina) were used. Blood samples were taken and the follow­ing parameters were determined: basal frequency of MN (BFMN), total red blood cells (RBC) count, hematocrit (Ht), hemoglobin (Hb), total and differential white blood cells (WBC). The BFMN determined for the species was 3.56 ± 1.39, while hematological parameters showed the following reference values: 0.937 ± 0.12 x106 RBC/μl, 27062.50 ± 4565.43 WBC/mm3, hematocrit 18 ± 1.81% and Hb concentration 4.80 ± 0.45 g/dl. Differential WBC counts were: 76 ± 2.90% for lymphocytes, 20.12 ± 2.56% for heterophils, 1.5 ± 0.19% for monocytes, and 2.12 ± 0.61% for eosino­phils, while no basophils were observed in any of the samples analyzed. No differences were observed between males and females in any of the variables analyzed. Data provided in this work could be useful as reference values for future studies of natural regions where P. hilarii occurs, employing this species as a sentinel organism for genotoxic and immunotoxic evaluation of environmental pollutants. © Firenze University Press.

Lopez Gonzalez E.C.,Proyecto Yacare Laboratorio Of Zoologia Aplicada Anexo Vertebrados | Lopez Gonzalez E.C.,CONICET | Latorre M.A.,Proyecto Yacare Laboratorio Of Zoologia Aplicada Anexo Vertebrados | Latorre M.A.,CONICET | And 5 more authors.
Pesticide Biochemistry and Physiology | Year: 2013

Caiman latirostris is one of the two crocodilian species living in Argentina. As a result of agricultural expansion produced in recent years, some populations are exposed to continuous pesticide discharge due to the proximity of its natural geographic distribution to extensive agricultural areas. The aim of this study was to evaluate genotoxicity and the effects on growth of Roundup® (RU; glyphosate based formulation) on C. latirostris hatchlings, considering concentrations commonly applied in crops and subsequently decay of the compound in water through time, as it might occur in the environment. C. latirostris 20. days old, from three different clutches, were exposed to two RU concentrations in plastic containers, during two months. RU concentration was progressively decreased through time, so experimental groups were: treatment 1: 11. mg/l (concentration at the beginning) to 2.5. mg/l (concentration at the end of experiment), treatment 2: 21. mg/l to 5. mg/l; and a control without RU. At the end of exposure period, blood samples were obtained and the micronucleus (MN) test applied in erythrocytes as a marker of genotoxicity. Results indicated a significant increase in the frequency of MN (p<0.05) and a tendency to lower growth in the groups exposed to RU compared to the negative control. These results, together with those reported in previous studies; warn about the effect that C. latirostris wild populations continuously exposed to low concentrations of pesticides might be suffering. © 2013 Elsevier Inc.

Simoncini M.S.,CONICET | Simoncini M.S.,Proyecto Yacare Laboratorio Of Zoologia Aplicada Anexo Vertebrados | Pina C.I.,CONICET | Pina C.I.,Proyecto Yacare Laboratorio Of Zoologia Aplicada Anexo Vertebrados | And 2 more authors.
Amphibia Reptilia | Year: 2011

Reproductive aspects, like number of nests produced per season or clutch size (number of eggs per nest), of broad-snouted caiman (Caiman latirostris) may be affected by a climatic variables such as rainfall and temperature. The success of caiman reproduction is not only affected by the amount of rainfall, but also by the time elapsed during which it takes place. In this study, we present evidence of a positive relationship between the number of nests produced and the amount of precipitation on the water heads ("Bajos Submeridionales") during March. Surprisingly, there was not a significant relationship when considering local rainfall and temperature. During one event of El Niño phenomena the number of caiman nests was the highest in eight years of monitoring, besides a remarkable low number of nests were produced during La Niña. There was not a significant relationship between clutch size and rainfall or temperature. This information is useful for the ranching programs, because managers will be able to estimate, nine months in advance, the number of nests for harvesting. Another positive aspect is that this information can be used to establish nests' searching strategies, and number of eggs to incubate and hatchlings to raise. Thus, this will help planning management strategies in support of conservation efforts for the species during extreme climatic events. © 2011 Brill Academic Publishers.

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