Elton Pinto Colares

Lactational transfer of PCBs and chlorinated pesticides in pups of southern elephant seals (Mirounga leonina) from Antarctica

Seven pairs of southern elephant seals (Mirounga leonina) pups and their dams were sampled during the late weaning season among a breeding population of seals on Elephant Island in Antarctica. The blubber of the pups and the milk and blubber of their dams were analyzed for lipid-normalized concentrations of PCBs and organochlorines compounds in order to evaluate the lactational transfer of these contaminants. The lipid-normalized concentrations in these tissues were in the ppb range (i.e., ngg(-1) lipid). The levels of contaminants in southern elephant seals were low in comparison with residues that have been reported in pinnipeds from the northern hemisphere. The relative tissue concentrations of the analytes measured followed the pattern: SigmaDDT>mirex>SigmaPCB>Sigmachlordane>HCB>heptachlor epoxide>dieldrin>methoxychlor>SigmaHCH>other organochlorines. The very high DDE/SigmaDDT ratio (0.91) in the blubber of dams and pups was an indicative of long-term, extremely distant pollution. On the other hand, the relatively high levels of some other organochlorine pesticides (e.g. mirex, heptachlor epoxide, dieldrin, methoxychor) may reflect the continued use of these insecticides in developing countries located in the southern hemisphere. For most of the analytes measured, the lipid-normalized concentrations were lower in pup blubber and in the milk than in the maternal blubber. Lactational transfer rates were dependent on the logK(ow) (octanol/water partition coefficient) values of the analytes measured, less lipophilic compounds being more readily transferred to the pups by the lactational route.

Seasonal variations in blood parameters of the Amazonian manatee, Trichechus inunguis

Seasonal variations in body weight, food consumption and blood glucose, total lipids, urea, total proteins, albumin and globulins of captive Amazonian manatees, Trichechus inunguis, were determined. Body weight changed significantly along the year, increasing from autumn to spring and decreasing in summer. The mean daily food intake of paragrass remained almost unchanged along the year. Paragrass administered to the manatees showed important variations in crude protein and lipid content along the year. No significant differences in blood parameters were registered between males and females in all seasons. Further, there were no significant differences in blood total proteins, albumin and globulins along the year. On the other hand, significant differences in the mean blood glucose, lipids and urea were registered. An increase in the blood glucose in the spring and summer was observed. Blood urea and lipids levels were positively related to paragrass protein and lipids content. These two correlations suggested that these blood parameters are good indicators of the animal nutritional status in the Amazonian manatee.

Surviving probability indicators of landing juvenile magellanic penguins arriving along the southern Brazilian coast

The aim of this work was to monitor and study the hematocrit and weight of juvenile penguins, with and without oil cover, found alive along the southern coast of Brazil, after capture, as well as before eventual death or release. Released juvenile penguins showed higher weight and hematocrit (3.65 ± 0.06 kg and 44.63 ± 0.29%, respectively) than those that died (2.88 ± 0.08 kg and 34.42 ± 1.70%, respectively). Penguins with higher hematocrit and weight after capture had higher mean weight gain than their counterparts with smaller hematocrit and weight after the capture. Besides, juveniles with higher hematocrit and weight after the capture had higher survival rates, independent of the presence or absence of oil. The results suggested that juveniles covered with oil might have been healthier than the juveniles without oil. The animals without oil probably died as a consequence of health disturbances, while the animals with oil possibly were healthy before contact with oil in the sea.

Seasonal pelage color change: news based on a South American Rodent

Mammalian seasonal molting and color change are known to be influenced by photoperiod changes. Calomys laucha, a South American rodent, exhibits seasonal pelage color change; however, unlike Northern hemisphere rodents, which present a gray or brown color during summer and a whitish color during winter, C. laucha pelage changes from an orange color during summer to a dark gray color during winter. Animals maintained for over a year in stationary photoperiod (LD 12:12h, 22 degrees C) presented orange pelage color during the summer corresponding month (January), and gray color during the winter corresponding month (July). Same age animals were evaluated during summer or winter months, and also showed different colors. Animals exposed for 12 weeks to summer or winter artificial conditions displayed color change, not according to the environmental conditions, as expected, but similar to that of animals maintained in stationary photoperiod. These results suggest that pelage color change in C. laucha is controlled by an endogenous circannual rhythm. The adaptive function of C. laucha color change is discussed.

Effects of increasing temperature on antioxidant defense system and oxidative stress parameters in the Antarctic fish Notothenia coriiceps and Notothenia rossii

Antioxidant defense system (ADS) and oxidative stress parameters were evaluated in the Antarctic fish Notothenia rossii and N. coriiceps exposed to increasing temperature. Acclimated fish were kept at 0°C or exposed to 4°C for 1day (N. rossii) or to 2 and 4°C for 1 and 6 days (N. coriiceps). Measurements were assessed in brain, gills, liver, white muscle and erythrocytes. Parameters analyzed included antioxidant capacity against peroxyl radicals (ACAP); reduced glutathione (GSH) and metallothionein-like proteins (MTLP) concentration; superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and glutamate-cysteine ligase (GCL) activity; lipid peroxidation (LPO) level and protein carbonyl (PC) concentration. Increased liver GST activity was observed in N. rossii exposed to 4°C for 1day. Increased muscle GPx activity was observed in N. coriiceps after exposure to 2°C for 1day. Reduced gill GPx activity and increased liver SOD activity were observed after exposure to 4°C for 1day. In N. coriiceps, increased gill GCL activity and reduced gill GPx activity, as well as reduced liver MTLP were observed after exposure to 2°C for 6 days. Reduced brain SOD activity and increased brain LPO; reduced gill ACAP, GSH concentration and GPx activity, as well as increased gill GCL activity; reduced liver ACAP, MTLP, SOD activity, GST activity and increased liver and erythrocytes LPO were observed after exposure to 4°C for 6 days. These findings indicate that ADS is more responsive to short-term increasing temperature in the sluggish N. coriiceps than in the active N. rossii. However, responses of N. coriiceps to long-term increasing temperature were transient and did not prevent tissue oxidative damage. Considering the predicted increase in temperature in the Southern Ocean over the next decades, our findings suggest that Antarctic fishes are sensitive to ocean warming, displaying tissue oxidative damage associated with the thermal stress.

Sperm impairments in adult vesper mice (Calomys laucha) caused by in utero exposure to bisphenol A

This study aimed to evaluate the effects of in utero administration of bisphenol A (BPA) on semen parameters of vesper mice. Sixty female Calomys laucha were divided into six groups and received by gavage during gestation the following substances: Water (negative control), Olive Oil (vehicle control), Diethylstilbestrol (DES – positive control – 6.5 μg kg−1 bw) and BPA (40, 80 and 200 μg kg−1 bw). Male offspring were euthanised at 70 days of age, and sperm parameters were analysed. BPA reduced normal sperm morphology (water = 96.1 ± 0.65; BPA200 = 96.8 ± 2.3%), sperm membrane integrity (water = 88.8 ± 1,65; BPA200 = 70.6 ± 4,15%), sperm motility (water = 87.5 ± 1.71; BPA200 = 51.3 ±9.9%) and in vitro penetration rates (water = 55.0 ± 7.14; BPA200 = 7.47 ±2.96%), but it did not affect body weight, anogenital distance, sperm DNA integrity and acrosome integrity. In conclusion, in utero exposure to BPA caused a reduction in sperm parameters of adult C. laucha. Natural mating studies should be conducted to verify the effects of BPA on fertility of the animals.

Sex steroid imbalances in the muricid Stramonita haemastoma from TBT contaminated sites.

Imposex incidence, organotin tissue levels, and sex steroid (free and esterified testosterone and estradiol) levels were assessed in Stramonita haemastoma from Babitonga Bay (Santa Catarina State, Southern Brazil). The imposex levels showed a reduction when compared to a previous evaluation performed in the same area. In spite of that, the detected imposex incidence indicated the occurrence of tributyltin (TBT) inputs that were still able to produce endocrine disruption in local gastropods. In addition, a high level of organotins was observed in tissues of imposexed females. These females also showed a hormonal imbalance, especially in the total testosterone/total estradiol ratio. These findings obtained under realistic field conditions suggest that the steroid pathway could be responsible by the imposex induction after exposure to TBT. In this case, measurements of sex steroid levels can be an additional evidence for monitoring sites and impose affected gastropod populations.

Antioxidant defense system and oxidative status in Antarctic fishes: The sluggish rockcod Notothenia coriiceps versus the active marbled notothen Notothenia rossii

Adaptive responses of antioxidant defense systems (ADS) to changes in increased levels of activity are critical, especially in Antarctic fishes. The benthopelagic marbled notothen (Notothenia rossii) shows higher spontaneous activity than the benthonic and sluggish rockcod (N. coriiceps). Therefore, we hypothesize that species-related responses of ADS would occur to counteract different rates of reactive oxygen species formation in these two Antarctic fish. Here we evaluated ADS and oxidative damage in tissues (brain, gills, liver and white muscle) of the two Antarctic fish. Despite no significant differences in lipid and protein oxidative damage were observed, we actually found species- and tissue-specific differences in ADS. Gill metallothionein-like proteins (MTLP) and liver reduced glutathione (GSH) concentrations were higher in N. coriiceps than in N. rossii. Brain and gill antioxidant capacity against peroxyl radicals (ACAP); gill enzyme [glutamate-cysteine ligase (GSL), superoxide dismutase (SOD) and catalase (CAT)] activity; liver GCL and SOD activity; and white muscle CAT activity were higher in N. rossii than in N. coriiceps. Therefore, the more active fish (N. rossii) maintains higher activities of enzymes involved in superoxide ions (O2.-) detoxification and GSH production in peripheral tissues (gills, liver and white muscle). This allows the more active fish (N. rossii) to keep levels of lipid and protein oxidative damage similar to those observed in the sluggish fish (N. coriiceps). It is worth noting that the more active fish also shows a higher brain antioxidant capacity, which could involve other non-enzymatic antioxidants like vitamins C and E. In contrast, N. coriiceps shows lower consumption of non-enzymatic antioxidants in peripheral tissues than N. coriiceps. As hypothesized, our results indicate that differences in ADS profiles between fish species are likely related to their habits and metabolic rates. This would imply in different fish abilities to deal with oxidative stress associated with increasing seawater temperature.

Feeding ecology of the Neotropical otter Lontra longicaudis in the Lower Arroio Grande River, southern Brazil

The present study was based on the analysis of spraints (n = 294) collected between December 2005 and November 2007. The importance of each type of prey was determined by absolute and relative frequency. Niche breadth was also estimated. The results were reported as mean (± SD) of relative frequencies. Fish were the main prey found in spraints (57.8 ± 7.0%). Fish from Callichthyidae family were the main prey, followed by Cichlidae, the species Hoplias malabaricus and the family Characidae. The frequencies of other fish and taxa were lower than 13.9% (absolute frequency) and 5.6% (relative frequency). Despite significant seasonal variations, (P = 0.001), niche breadth values were low in all seasons (0.39 ± 0.11). Therefore, Lontra longicaudis presented a narrow niche breadth as a result of consistent fish predation. Based on these data, fish with rapid movement presenting territorial behavior and benthic fish with slow movements are the most consumed. Seasonal fluctuations are caused by the increase of secondary prey in the diet during some seasons.

Diet of Lontra longicaudis (Olfers) in a coastal stream in southern Rio Grande do Sul State, Brazil

Este estudo apresenta dados referentes a composicao da dieta de Lontra longicaudis em um arroio costeiro com vegetacao riparia, localizado na regiao sul da Planicie Costeira do Rio Grande do Sul, Brasil. Entre fevereiro de 2007 e maio de 2008, 242 amostras de fezes e seis restos alimentares foram coletados em um trecho de aproximadamente 1.100 m do arroio Bolaxa, na Area de Protecao Ambiental da Lagoa Verde. Os itens identificados como os mais consumidos foram peixes (82,6%), seguidos por crustaceos decapodes (20,6%). Outros itens, encontrados em menor frequencia, foram: aves, mamiferos, repteis, anfibios, insetos e moluscos. Na analise dos restos alimentares, foi possivel a identificacao de Conepatus chinga (Carnivora: Mephitidae) e Rhamdia quelem (Siluriformes: Heptapteridae). Dentre os peixes, a familia mais frequente nas amostras fecais foi Cichlidae (59,5%), seguida por Curimatidae (32,6%). Outras familias, encontradas em menor frequencia, foram Erythrinidae, Heptapteridae, Characidae, Mugilidae, Callichthyidae e Synbranchidae. Foi verificada uma dieta variada, reflexo, em parte, da influencia dos ecossistemas adjacentes sobre a area de estudo. Palavras-chave: lontra neotropical, Lontra longicaudis , itens alimentares, Planicie Costeira.