Valores de DL50 em peixes e no rato tratados com p�� de ra��zes de Derris spp e suas implica����es ecotoxicol��gicas

Os timb��s verdadeiros (plantas do g��nero Derris), origin��rios da Amaz��nia Brasileira, tem demonstrado import��ncia crescente por produzirem uma classe de compostos flavono��dicos relacionados �� rotenona, que possuem atividade t��xica para peixes e mam��feros. Neste estudo foi determinado a dose letal 50% (DL50) do extrato alco��lico do p�� de Derris spp para tr��s esp��cies de peixes filogeneticamente diferentes e um mam��fero roedor (rato). As DL50 de 2,6 microgramas/ml para Collosoma macropomum (tambaqui), 4,8 microgramas/ml para Oreochromis niloticus (til��pia), 14,2 microgramas/ml para Plecostomus sp (cascudo) e DL50 de 100,0 mg/kg para Rattus norvegicus (rato) denotam acentuadas diferen��as entre os valores de DL50, principalmente entre os peixes e o rato. Isto possivelmente �� devido a fatores farmaco-cin��ticos que se relacionam com as diferentes barreiras teciduais encontradas pelos roten��ides quando administrados pela via oral em mam��feros.

O papel dos hormônios leptina e grelina na g��nese da obesidade

A preval��ncia da obesidade est�� aumentando e estudos prospectivos mostram que, em 2025, o Brasil ser�� o quinto pa��s do mundo a apresentar problemas de obesidade em sua popula����o. A etiologia da obesidade n��o �� de f��cil identifica����o, uma vez que a mesma �� caracterizada como uma doen��a multifatorial, ou seja, diversos fatores est��o envolvidos em sua g��nese, incluindo fatores gen��ticos, psicol��gicos, metab��licos e ambientais. Pesquisas recentes na ��rea de metabolismo mostram que o adip��cito �� capaz de sintetizar v��rias subst��ncias e, diferentemente do que se supunha anteriormente, o tecido adiposo n��o �� apenas um s��tio de armazenamento de triglic��rides, �� hoje considerado um ��rg��o end��crino. Dentre as diversas subst��ncias sintetizadas pelo adip��cito, destacam-se a adiponectina, a angiotensina e a leptina. A leptina �� um pet��deo que desempenha importante papel na regula����o da ingest��o alimentar e no gasto energ��tico, gerando um aumento na queima de energia e diminuindo a ingest��o alimentar. Al��m dos avan��os no estudo da c��lula adiposa, um novo horm��rnio relacionado ao metabolismo foi descoberto recentemente, a grelina. A grelina �� um pept��deo produzido nas c��lulas do est��mago, e est�� diretamente envolvida na regula����o do balan��o energ��tico a curto prazo. Assim, este artigo abordar�� o papel da leptina e da grelina no controle do peso corporal e as limita����es que ainda existem para tratar a obesidade em humanos.

Respostas da Til��pia do Nilo (Oreochromis niloticus) �� atratividade e palatabilidade de ingredientes utilizados na alimenta����o de peixes

Avaliaram-se as respostas da til��pia do Nilo �� atratividade e palatabilidade de 14 ingredientes. O m��todo utilizado foi de dupla escolha, comparando-se cada ingrediente peletizado �� uma ra����o controle. Foram empregados quatro aqu��rios (750 litros) contendo, cada um, tr��s alevinos e dois comedouros instalados nos cantos direito e esquerdo, sendo registrados tempo decorrido entre coloca����o do ingrediente e chegada dos animais aos comedouros, freq����ncia de visitas aos comedouros, n��mero de gr��nulos ingeridos e freq����ncia de eje����es. Os tratamentos foram comparados pela prova n��o-param��trica de Kruskal-Wallis e a compara����o dos ingredientes para o conjunto de vari��veis, por interm��dio da An��lise de Agrupamento e An��lise de Componentes Principais. Os ingredientes foram assim classificados: a) baixa atrato-palatabilidade = farelos de trigo, soja e algod��o, farinha e raspa de mandioca, farinha de girassol e fub�� de milho, b) m��dia atrato-palatabilidade = levedura de cana-de-a����car e gl��ten de milho e c) alta atrato-palatabilidade = ovo integral liofilizado, farinhas de cris��lidas, peixes, carne e camar��o. Ingest��o de gr��nulos (manh�� e tarde) e freq����ncia de visitas aos comedouros (tarde) foram consideradas as vari��veis mais discriminat��rias e freq����ncia de eje����o de gr��nulos e tempo gasto para aproxima����o dos comedouros (manh�� e tarde), as menos discriminat��rias. As respostas comportamentais dos peixes variaram de acordo com o ingrediente apresentado. A avalia����o do grau de atrato-palatabilidade deve ser realizada considerando-se uma combina����o de par��metros.

Concentra����es plasm��ticas de cortisol, hormônios tiro��deanos, metab��litos lip��dicos e temperatura corporal de cabras alpinas submetidas ao estresse t��rmico

The objective of this work was to determine the plasma concentrations of cortisol, thyroid hormone, lipids metabolites and corporal temperature or lactating Alpine goats submitted to heat stress. Six lactating Alpine goats were allotted randomly in a crossover experimental design for two groups: thermoneutral conditions or thermal stress. An adaptation period of 28 days was followed by Four-periods of 14 days each, when the animals submitted to thermal stress were exposed to the average temperature of 33.84 degrees C; THI of 86.20; BGT of 36.18 and BT of 32.11 degrees C from 8:00 am to 5:00 pm, including simulated solar radiation from 10:00 am to 3:00 pm. There were no differences between the groups in the plasma concentrations of cortisol, thyroid hormones (T-3-triiodothyronine and T-(4) tiroxine), and lipid metabolites (cholesterol and HDL). Rectal temperature was higher during thermal stress when compared to the group of animals in thermoneutral conditions. The goats maintained the thyroid plasma hormone concentrations, when exposed to repealed and intermittent stress, in spite of the occurrence of hypertermia during heat stress.

Partilha de Recursos Alimentares em Peixes em um Riacho de Serra do Sudeste do Brasil

We studied the diet and food resources partitioning by fishes from the Ita��na stream, municipality of Itatinga, Southeastern Brazil. Eighteen species of fish were collected, being Microlepidogaster sp., Hypostomus sp., Astyanax sp., Phalloceros caudimaculatus and Heptapterus sp. the most frequent and abundant ones. Regarding diet, the majority of the species were observed to be insectivorous (61%), while insectivorous-herbivorous and periphyton feeders ranked 22 and 17%, respectively. The food overlap analysis revealed many cases of similarity between the diets. For most cases, however, a detailed analysis of food items and spatial distribution of the species showed differences between the couples under analysis which points toward a reduction in competition for food.

Acao antioxidante de extratos de alecrim (Rosmarinus officinalis L.) em files de peixes da especie pacu (Piaractus mesopotamicus Holmberg)

The antioxidant effect of plant extract has been an interesting issue for many researchers in past few years. Spices have been identified as products with large amounts of antioxidants, and rosemary is one the most studied spice. Studies have shown evidences that population with high intake of these substances have less incidence of coronary heart disease. The objective of this work was verify the antioxidant action of the commercial rosemary oleoresin Herbalox�� (used to feed the pacu (Piaractus mesopotamicus) fish. The juveniles pacu were fed with isocaloric and isoproteic diets, for two groups the lipid source was soybean oil and for the another it was corn oil. For each group of the different lipid sources, rosemary extract Herbalox�� (were added in one lot and on the other which was used as control. The results showed that the addition of rosemary extracts to the ration protected them against peroxidation, when compared with the control, the lipid source also have influence on these protection.

Preval��ncia, sazonalidade e intensidade de infec����o por Diplostomum (Austrodiplostomum) compactum Lutz, 1928 (Digenea, Diplostomidae), em peixes do reservat��rio de Volta Grande, Estado de Minas Gerais, Brasil

The present study was conducted in the Aquaculture Station of Hydroeletric Power Station situated in Volta Grande Reservoir, MG, Brazil. Seventy freshwater corvinas, Plagiscion squamosissimus, and 66 tucunar��s, Cichla ocellaris were captured bimonthly from April 2000 through April 2001 with net and hook. The helmints were identified as Diplostomun (A.) compactmn which showed the highest prevalence in the corvina's eyes in April 2000 (70%), February 2001 (80%) and April 2001 (60%), while in tucunar�� occurred in April 2000 (33.3%), August 2000 (18.2%) and October 2000 (18.2%). Nevertheless, increase in the mean intensity of parasites was related in April (6.6), June (6.0), August (18.5) 2000 and February (5.7), April (4.8) 2001 for corvina and in August (16.0) and October (7.0) 2000 for tucunar��. Corvina's females showed infection during all period, while males did not show the same prevalence in June 2000 and April 2001. On the other hand, tucunare's males were infected in all months while females in August and October 2000. The highest prevalence in corvina was observed in the months which presented elevated water temperature (April, October, December 2000 and April 2001). The number of parasites collected in corvina on February 2000 was higher than the one observed in August 2000. The same was not observed for tucunar��. This work demonstrate corvina's high susceptibility to metacercariae of Diplostomum.

Metacerc��rias de Diplostomum (Austrodiplostomum) compactum Lutz, 1928 (Digenea, Diplostomidae) em peixes do rio Paran��, Brasil. Preval��ncia, sazonalidade e intensidade de infec����o

This paper aims at evaluating the occurrence of Diplostommn (Anstrodiplostomum compactum (Digenea: Diplostomatidae) in the eyeball of Plagioscion sqnamosissimus (corvina) and Cichla ocellaris (tucunar��), monthly captured in Paran�� river, Presidente Epit��cio, state of S��o Paulo, Brazil. From 61 corvinas under analysis, 56 of them contained parasites (92%) with intensity rate of 42.0 host parasites. From an amount of 81 tucunar��s, 45 contained parasites (55%) with intensity rate of 9.3 parasites. Corvinas showed prevalence from 71 to 100% with the highest intensity rates (103.3 and 106.9) from February to March, 2001. Comparatively, the tucunar�� showed the highest prevalence from November 2000 (90%) to February 2001 (80%). The tucunar�� highest intensity rates occurred on September, 2000 (12.7), December, 2000 (12.2) and February, 2001 (16.1). Metacercariae showed a hollow womb body and a posterior region of a sinuous conic protuberance, an oral sucker smaller than the acetabulae, a simple acetabulae located in the pre-equatorial region of helminto. A short pre-pharynx followed by a muscular pharynx, genital pore next to acetubulae. Corvina metacercariae presents 1.434,0 ��m (880 to 1.840) long by 611.2 �� 93.4 ��m (400 to 792) wide. Tucunar�� metacercariae, 1.462.4 ��m (960 to 2.480) by 710.8 ��m (560 to 960). Authors confirmed corvina great susceptibility to Diplomastum and the relationship between the parasitism and the aquatic and climatic parameters.

Associa����es de esp��cies de peixes em ambientes l��ticos da bacia do rio Iguatemi, Estado do Mato Grosso do Sul

The aim of this paper is to describe the patterns of associations between fish species and their distribution in lotic habitats at basin level. Samples were accomplished in 27 localities of Iguatemi river basin, distributed in four environments (Iguatemi river, Jogui river, Puit�� river and streams). The presence/absence data of those species which occurred in 2 or more sites were submitted at multivariate methods with the aim to describe the major species associations. The species distribution was considered determinative in these communities (C-score = 17,33; P = 0,000), with significant difference among the studied environments (ANOSIM r = 0,082; P = 0,012), with verified difference between Iguatemi river and streams (P = 0,001) and also streams and Jogui river (P = 0,014). We verified a strong segregation among species from headstreams and more discharge river stretches or even larger streams.

Influ��ncia do alecrim (Rosmarinus officinallis L.) na atividade de ��gua e oxida����o lip��dica de peixes de uma esp��cie de til��pia (Oreochromis ssp-var. vermelha Fl��rida) submetidos �� salga

Salting have been a very utilized fish conservation method, however only in the last years the basic mechanism involved in salting fish has been understood. The objectives of this study were determine the addition in brine salt of rosemary leaves, rosemary extracts and tocopherol, and your action in the followed parameters: water activity (Aw), moisture, ash, salt content and TBARS. The results showed that the addition of antioxidants was difficulted the salt absorption, however didn't have differences between rosemary or tocopherol use. In the salting time of 3 hours the values of Aw and salt levels, was respectively: 0.77��0.01 and 14.42��1.69. for control treatment; 0.85��0.02 and 9.09��1.39for rosemary filtrate; 0.78��0.03 and 10.63��0.69 rosemary without filtrating and 0.85��0.02 and 11.96��1.78 tocopherol, showed that didn't grow indigenous bacterias. Lipid oxidation was evaluated by TBARS and the results showed the oxidative effect of salt and the pro oxidant effects of alls antioxidants used in brine salting.

Habitat, distribui����o e aspectos adaptativos de peixes da microbacia do ribeir��o Grande, Estado de S��o Paulo, Brasil

The ichthyofauna of ribeir��o Grande microbasin that runs through one of the few remaining fragments of Atlantic Forest (in Mantiqueira mountain range, Valley of Para��ba) was studied. Fish samples were obtained with an electric fishing powered by a maximum capacity generator of 155 V and 60-Hz alterning current, gill-nets and traps. In three collecting days, during July/2001, October/2001, January/2002 and April/2002, 2865 fishes were sampled. These fishes belonged to 12 families, 23 genera and 37 species. The species were more abundant between the piedmont and the plain of the Valley of Para��ba. The Characidium, Trichomycterus genera and the Imparfinis minutus species presented only one ovary or testis and no swim bladder. The ecological significance of morphological features in stream mountain fishes was used to predict the niche adaptation for those conditions, towards K-strategy.

Organiza����o das assembl��ias de peixes em riachos da bacia do rio Iguatemi, Estado do Mato Grosso do Sul

Aiming to describe the patterns of the fish assemblages organization in streams of the Iguatemi River basin we sampled streams with seine nets and sieves from November/1999 to August/2000. We collected 567 individuals distributed in 24 species. We detected statistically significant influence of the streams characteristics upon species diversity. The species composition was hardly explained by the physical and chemical characteristics of the streams. Then we detected significant influence of the fish ecomorphology in the species occurrence (Mantel r = -0.34; P = 0.04), but not in the distribution of its abundance (Mantel r = -0.21; P = 0.07). We verified through the species co-occurrence index (C-score) that its composition in the studied streams is stochastic.

Uso do grau de prefer��ncia alimentar para a caracteriza�� ��o da alimenta����o de peixes na APA de S��o Pedro e Anal��ndia

We studied feeding habits of four fish species in two watershed at APA - ��rea de Prote����o Ambiental (Area of Environmental Protection) in S��o Pedro and Anal��ndia, State of S��o Paulo, southeastern Brazil. Feeding Preference Degree (FPD) was used to demonstrate the importance of each food item for the species of both basins. Feeding habits of both species of lambari was variable. The allochtonous items such as insects, autochtonous items, and vegetal material were very important, characterizing omnivory. The bagre (Rhamdia quelen) fed mainly on insects at the Jacar��-pepira Basin and also on fishes at the Corumbata�� basin. The cascudo Hypostomus strigaticeps ingested autochtonous vegetal material and sediments at both basins.

Fauna parasit��ria de peixes oriundos de pesque-pague do munic��pio de Guariba, S��o Paulo, Brasil

This study describes the occurrence and the seasonality of parasites of cultivated fish from a fee fishing farm located in Guariba, S��o Paulo State, Brazil (21��15'22'' S, 48��18'58'' W and 595 m of altitude), from August, 2001 to July, 2002. The presence of parasites was researched in pacu Piaractus mesopotamicus (Characidae), common carp Cyprinus carpio (Cyprinidae), nile-tilapia Oreochromis niloticus (Cichlidae), tambacu hybrid (male of P. mesopotamicus x female of tambaqui-Colossoma macropomum) and piraputanga Brycon hillari (Characidae). Results demonstrate that out of 100 fish examined, 15% were sponged for at least one of the following parasites: Trichodina sp.; monogenean helminths; copepodits of Lemaea cyprinacea; adults of L. cyprinacea; or Dolops carvalhoi. In decreasing order, the susceptibility degree of the hosts was C. carpio, P. mesopotamicus, B. hillari, tambacu hybrid and O. niloticus. In decreasing order the reported parasites were monogenean helminths, Dolops carvalhoi, Trichodina sp., adults of Lernaea cyprinacea and their young shapes.

O impacto da pesca do camar��o-rosa Farfantepenaeus paulensis (Perez-Farfante) (Decapoda, Penaeidae) nas assembl��ias de peixes e siris do Parque Nacional da Lagoa do Peixe, Rio Grande do Sul, Brasil

This work evaluates the impact of the pink shrimp Farfantepenaeus paulensis (Perez-Farfante, 1967) fishery on fish and crab assemblages of Lagoa do Peixe National Park, Brazil. We observed that composition of catches is similar to shrimp fisheries using fyke-net at others estuaries of Rio Grande do Sul State: pink shrimp (53%), accessory catches (24%) and bycatch (23%). However, fishery composition showed distinct differences along the saline gradient of the main park's lagoon. Regarding only fish species, the most impacted species in this fishery were Brevoortia pectinata (Jenyns, 1842), Micropogonias furnieri (Desmarest, 1823), and Jenynsia multidentata (Jenyns, 1842). In others estuaries from Rio Grande do Sul, in contrast, the most impacted species were M. furnieri, Genidens barbus (Lacep��de, 1803) and Genidens genidens (Cuvier, 1829). The potential impact of the pink shrimp fishery at Lagoa do Peixe National Park seemed to be weaker when compared to shrimp fisheries elsewhere. We believe that the decision to prohibit this fishery at the Lagoa do Peixe National Park should not be based on its potential damage to the fish and crab assemblages but based on the simple fact that Brazilian laws do not allow fisheries inside National Parks.