Trophic relationships among three species of ornamental fish from the region of Lake Amanã, Amazon

Abstract The present study objectified to evaluate the trophic relationships and the possible aggressive mimicry involving Carnegiella strigata, Carnegiella marthae and Gnathocharax steindachneri, in lowland forest streams. Samplings occurred in November 2002, March and August 2003 in Amanã Sustainable Development Reserve (ASDR). The total of 943 fish was caught, being 79.43% of C. marthae, 3.18% of C. strigata and 17.39% of G. steindachneri. Stomach contents, degree of stomach repletion, relative volume and frequency of occurrence of food items were evaluated. Thirteen food items were identified, and the presence of terrestrial and aquatic insects indicates the high dependence of these species and the flooded forest. Low feeding overlap was observed between Carnegiella strigata and C. marthae compared to Gnathocharax steindachneri. However, the overlap between the two Carnegiella species was relatively high, which could explain the low frequency of syntopic occurrence among these species, suggesting a possible case of competitive exclusion.

Resumo Este estudo teve como objetivo analisar as relações tróficas e a possível existência de uma relação de mimetismo agressivo envolvendo Carnegiella strigata, Carnegiella marthae e Gnathocharax steindachneri, em igarapés de terra firme. As coletas ocorreram em novembro de 2002, março e agosto de 2003 e foram realizadas na Reserva de Desenvolvimento Sustentável de Amanã (RDSA). Foram capturados 943 peixes, onde C. marthae representou 79,43%, C. strigata 3,18% e G. steindachneri 17,39%. Foram analisados os conteúdos estomacais e verificados grau de repleção, volume relativo e frequência de ocorrência dos alimentos. Foram identificados 13 itens alimentares, onde insetos terrestres e aquáticos denotaram alto grau de dependência destas espécies em relação à floresta alagada. Ocorreu baixa sobreposição alimentar das espécies Carnegiella strigata e C. marthae em relação a Gnathocharax steindachneri. Entretanto, a sobreposição entre as duas espécies de Carnegiella foi relativamente alta, o que poderia explicar a baixa frequência de ocorrência sintópica entre essas espécies, sugerindo um possível caso de exclusão competitiva.

Trophic relationships among three species of ornamental fish from the region of Lake Amanã, Amazon / Relações tróficas entre três espécies de peixes ornamentais da região do lago de Amanã, Amazonas

The present study objectified to evaluate the trophic relationships and the possible aggressive mimicry involving Carnegiella strigata, Carnegiella marthae and Gnathocharax steindachneri, in lowland forest streams. Samplings occurred in November 2002, March and August 2003 in Amanã Sustainable Development Reserve (ASDR). The total of 943 fish was caught, being 79.43% of C. marthae, 3.18% of C. strigata and 17.39% of G. steindachneri. Stomach contents, degree of stomach repletion, relative volume and frequency of occurrence of food items were evaluated. Thirteen food items were identified, and the presence of terrestrial and aquatic insects indicates the high dependence of these species and the flooded forest. Low feeding overlap was observed between Carnegiella strigata and C. marthae compared to Gnathocharax steindachneri. However, the overlap between the two Carnegiella species was relatively high, which could explain the low frequency of syntopic occurrence among these species, suggesting a possible case of competitive exclusion.

Este estudo teve como objetivo analisar as relações tróficas e a possível existência de uma relação de mimetismo agressivo envolvendo Carnegiella strigata, Carnegiella marthae e Gnathocharax steindachneri, em igarapés de terra firme. As coletas ocorreram em novembro de 2002, março e agosto de 2003 e foram realizadas na Reserva de Desenvolvimento Sustentável de Amanã (RDSA). Foram capturados 943 peixes, onde C. marthae representou 79,43%, C. strigata 3,18% e G. steindachneri 17,39%. Foram analisados os conteúdos estomacais e verificados grau de repleção, volume relativo e frequência de ocorrência dos alimentos. Foram identificados 13 itens alimentares, onde insetos terrestres e aquáticos denotaram alto grau de dependência destas espécies em relação à floresta alagada. Ocorreu baixa sobreposição alimentar das espécies Carnegiella strigata e C. marthae em relação a Gnathocharax steindachneri. Entretanto, a sobreposição entre as duas espécies de Carnegiella foi relativamente alta, o que poderia explicar a baixa frequência de ocorrência sintópica entre essas espécies, sugerindo um possível caso de exclusão competitiva.

Trophic relationships among three species of ornamental fish from the region of Lake Amanã, Amazon / Relações tróficas entre três espécies de peixes ornamentais da região do lago de Amanã, Amazonas

The present study objectified to evaluate the trophic relationships and the possible aggressive mimicry involving Carnegiella strigata, Carnegiella marthae and Gnathocharax steindachneri, in lowland forest streams. Samplings occurred in November 2002, March and August 2003 in Amanã Sustainable Development Reserve (ASDR). The total of 943 fish was caught, being 79.43% of C. marthae, 3.18% of C. strigata and 17.39% of G. steindachneri. Stomach contents, degree of stomach repletion, relative volume and frequency of occurrence of food items were evaluated. Thirteen food items were identified, and the presence of terrestrial and aquatic insects indicates the high dependence of these species and the flooded forest. Low feeding overlap was observed between Carnegiella strigata and C. marthae compared to Gnathocharax steindachneri. However, the overlap between the two Carnegiella species was relatively high, which could explain the low frequency of syntopic occurrence among these species, suggesting a possible case of competitive exclusion.

Este estudo teve como objetivo analisar as relações tróficas e a possível existência de uma relação de mimetismo agressivo envolvendo Carnegiella strigata, Carnegiella marthae e Gnathocharax steindachneri, em igarapés de terra firme. As coletas ocorreram em novembro de 2002, março e agosto de 2003 e foram realizadas na Reserva de Desenvolvimento Sustentável de Amanã (RDSA). Foram capturados 943 peixes, onde C. marthae representou 79,43%, C. strigata 3,18% e G. steindachneri 17,39%. Foram analisados os conteúdos estomacais e verificados grau de repleção, volume relativo e frequência de ocorrência dos alimentos. Foram identificados 13 itens alimentares, onde insetos terrestres e aquáticos denotaram alto grau de dependência destas espécies em relação à floresta alagada. Ocorreu baixa sobreposição alimentar das espécies Carnegiella strigata e C. marthae em relação a Gnathocharax steindachneri. Entretanto, a sobreposição entre as duas espécies de Carnegiella foi relativamente alta, o que poderia explicar a baixa frequência de ocorrência sintópica entre essas espécies, sugerindo um possível caso de exclusão competitiva.

Trophic relationships among three species of ornamental fish from the region of Lake Amanã, Amazon.

The present study objectified to evaluate the trophic relationships and the possible aggressive mimicry involving Carnegiella strigata, Carnegiella marthae and Gnathocharax steindachneri, in lowland forest streams. Samplings occurred in November 2002, March and August 2003 in Amanã Sustainable Development Reserve (ASDR). The total of 943 fish was caught, being 79.43% of C. marthae, 3.18% of C. strigata and 17.39% of G. steindachneri. Stomach contents, degree of stomach repletion, relative volume and frequency of occurrence of food items were evaluated. Thirteen food items were identified, and the presence of terrestrial and aquatic insects indicates the high dependence of these species and the flooded forest. Low feeding overlap was observed between Carnegiella strigata and C. marthae compared to Gnathocharax steindachneri. However, the overlap between the two Carnegiella species was relatively high, which could explain the low frequency of syntopic occurrence among these species, suggesting a possible case of competitive exclusion.

Fontes de óleos vegetais em dietas para acará-bandeira (Pterophyllum scalare, Cichlidae): crescimento e tolerância térmica / Vegetable oil sources in diets for freshwater angelfish (Pterophyllum scalare, Cichlidae): growth and thermal tolerance

The influence of fatty acid composition of the diets on the productive performance and on cold and heat tolerance of juvenile freshwater angelfish (Pterophyllum scalare), in three different phases, was studied. Phase I studied the productive performance of freshwater angelfish in a completely randomized experimental design with four treatments, canola, linseed, olive and soybean oils and four replicates during 50 days using 192 fish in 16 aquaria. Phase II studied the cold tolerance of juvenile freshwater angelfish using 72 juvenile freshwater angelfish, coming from phase I and maintained in 12 aquaria climatized chamber. The temperature was reduced 1ºC per day, until the observation of 100 percent fish mortality. Phase III, it was studied the heat tolerance of juvenile freshwater angelfish employing an identical procedure to phase II, but with a daily increase of 1ºC. Significant differences (P>0.05) were not observed for any parameters evaluated. Thus, it was concluded that the type of vegetable oil (canola, linseed, olive and soybean) used as a diet supplement did not affect the productive performance, nor the tolerance to cold and heat, of juvenile freshwater angelfish.

Avaliou-se a influência da suplementação de lipídeos na dieta, com diferentes composições de ácidos graxos, sobre o desempenho produtivo e tolerância ao frio e ao calor de juvenis de acará-bandeira (Pterophyllum scalare). O experimento foi realizado em três fases. Na fase um avaliou-se o desempenho produtivo dos peixes em delineamento inteiramente ao acaso com quatro tratamentos - óleos de canola, linhaça, oliva e soja - e quatro repetições, durante 50 dias usando 192 peixes distribuídos em 16 aquários. Na segunda fase, avaliou-se a tolerância ao frio, usando 72 peixes, procedentes da fase um, distribuídos em 12 aquários e mantidos em câmara climatizada. A temperatura foi reduzida de 1ºC por dia até a observação de 100 por cento de mortalidade dos peixes. Na fase três, avaliou-se a tolerância ao calor com procedimentos semelhantes aos da fase dois, porém a temperatura foi elevada 1ºC por dia. Não foram observadas diferenças significativas (P>0,05) para os parâmetros avaliados. Conclui-se que a suplementação de óleos vegetais nas dietas não inferiu no desempenho produtivo e na tolerância ao frio e ao calor de juvenis de acará-bandeira.

Muscle delta13C change in Nile tilapia (Oreochromis niloticus) fingerlings fed on C3-or C4-cycle plants grain-based diets.

The effects of grain-based diets from C3 or C4-cycle plants on muscle delta(13)C change process in Nile tilapia (Oreochromis niloticus) fingerlings were investigated. Two groups of sex reversal males Nile tilapia fingerlings were fed with isoproteic (32.0% DP) and isocaloric (3200 kcal DE/kg) diets, differing from each other by their delta(13)C. Muscle samples were collected and the carbon isotopic composition was measured. For C4 diet, the formula for the muscle delta(13)C change related to the intake time of a new diet was delta(13)C=-14.88-9.21e(-0.0209t) and the half-life (T) of the muscle carbon was 33.2 days. For C3 diet, the formula was delta(13)C=-25.43+8.59e(-0.0533t) with T=13 days. The C3 diet was considered more appropriate based on its palatability and consequent larger food intake than the C4 diet, resulting in an increased muscle delta(13)C change rate. However, for future studies, would be necessary to mix both the C3 and C4 feedstuffs to formulate diets nutritionally appropriated, with contrasting stable isotopes signatures. Tissue delta(13)C change rate is therefore indicated as a promising tool to better understand the biotic and abiotic factors that influence nutrients utilization from the diet and animal growth.

Muscle delta13C change in Nile tilapia (Oreochromis niloticus): effects of growth and carbon turnover.

The contribution of growth and turnover to the muscle delta(13)C change process was investigated using mathematical models which associate delta(13)C change to time of intake of a new diet or increase in body mass. Two groups of Nile tilapia (Oreochromis niloticus) were fed on diets based on C3 (delta(13)C=-25.64+/-0.06 per thousand) or C4 (delta(13)C=-16.01+/-0.06 per thousand) photosynthetic cycle plants to standardize the muscle delta(13)C. After establishing the carbon isotopic equilibrium, fish (mean mass 24.12+/-6.79 g) then received the other treatment diet until a new carbon isotopic equilibrium could be established, characterizing T1 (C3-C4) and T2 (C4-C3) treatments. No significant differences were observed in fish productive performance. Good fits were obtained for the models that associated the delta(13)C change to time, resulting in carbon half-life values of 23.33 days for T1 and 25.96 days for T2. Based on values found for the muscle delta(13)C change rate from growth (0.0263 day(-1) and 0.0254 day(-1)) and turnover (0.0034 day(-1) and 0.0013 day(-1)), our results indicate that most of the delta(13)C change could be attributed to growth. The application of model that associated the delta(13)C change to body mass increase seems to produce results with no apparent biological explanation. The delta(13)C change rate could directly reflect the daily ration and growth rate, and consequently the isotopic change rates of carbon and other tissue elements can be properly used to assess different factors that may interfere in nutrient utilization and growth.

Quantitative cell-cycle protein expression in oral cancer assessed by computer-assisted system.

The knowledge of cell-cycle control has shown that the capacity of malignant growth is acquired by the stepwise accumulation of defects in specific genes regulating cell growth. Histologic diagnosis might be improved by a quantitative evaluation of more specific diagnosis biomarkers, which could help to precisely identify pre-malignant and malignant oral lesions. The aim of the present study is to evaluate whether computer-based quantitative assessment of p53, PCNA and Ki-67 immunohistochemical expression, could be used clinically to foresee the risk of oral malignant transformation. This retrospective study was carried out in ninety-five oral biopsies, 27 were classified as fibrous inflammatory hyperplasia, 40 as leukoplakia and 28 as oral squamous cell carcinoma. Sixteen out of the 40 leukoplakia were diagnosed as non-dysplastic leukoplakia, the other 24 being dysplastic leukoplakia, of which 50.0% were classified as moderate to severe dysplasia. Comparison of the four groups of oral tissues showed significant rises in p53 and Ki-67 positivity index, which increased steadily in the order benign, pre-malignant, and malignant. In contrast, it was not possible to relate higher PCNA levels with pre-malignant and malignant oral lesions. We therefore conclude that PCNA immunohistochemistry expression is probably an inappropriate marker to identify oral carcinogenesis, whereas joint quantitative evaluation of p53 and Ki-67, appears to be useful as a tumor marker, providing a pre-diagnostic estimate of the potential for cell-cycle deregulation of the oral proliferate status.

Efeito do laser terapeutico de baixa potencia sobre o processo de reparacao ossea em Tibia de Rato / Effect of low power therapeutic laser on process of bone healing in Rat Tibia

Este estudo teve por objetivo avaliar os efeitos do laser terapeutico de baixa potencia sobre o processo de reparacao ossea em tibia de rato. O modelom experimental consistiu na realizacao de uma osteotomia mecanica por escareacao na face medial da tibia de 48 ratos machos, utilizando uma broca odontologica de aco cilindrica. Os animais foram divididos em 3 grupos, sendo que os grupos 1 e 2 foram irradiados com laser na dose de 5 J/cm2 e 50 J/cm2, respectivamente, enquanto o grupo 3 (controle) recebeu tratamento, respectivamente. Os parametros referentes ao tecido de reparo avaliados foram: 1. comportamento biomecanico ao final de 14 dias PO e 2. morfologia ao final de 7 e 14 dias do PO, referentes ao tecido de reparo. Os chados das analises histomorfologicas dos 7 dias do PO demonstraram melhor evolucao do processo de reparacao no grupo irradiado com a dose de 50 J/cm2, comparado aos demais grupos. Esses resultados sugerem que, sob as condicoes xperiemntais da investigacao, terapia laser de baixa potencia (LLLT) favorece o processo de reparacao ossea durante seus estagios iniciais