RESUMO: O presente trabalho baseia-se na análise do conteúdo estomacal de Astyanax lacustris, capturados mensalmente no período de setembro de 2006 a agosto de 2007 na Lagoa do Piató, Assu, Rio Grande do Norte, Brasil. Como instrumento de captura utilizou-se rede de espera com malha de 4 cm entrenós. Foram obtidos de cada exemplar o comprimento total, comprimento padrão, massa corporal total e peso do estômago. A análise do conteúdo estomacal de 360 peixes foi realizada de acordo com o método volumétrico, de pontos e o método de frequência de ocorrência, aplicando-se sobre este o Índice de Importância Alimentar. Os estômagos tiveram o grau de repleção determinado e foi calculado o Índice de Repleção. As variações na dieta e a frequência de ingestão alimentar foram relacionadas com a pluviosidade e os fatores limnológicos. Os itens alimentares identificados foram separados em grupos distintos de acordo com a sua origem. Concluiu-se que a espécie apresenta hábito alimentar onívoro, com tendência à insetivoria e com maior atividade alimentar durante a estiagem. A concentração do oxigênio dissolvido teve maior relação com a frequência de alimentação do que a pluviosidade e os demais fatores físico-químicos da água.Palavras-chave: dieta, peixe, insetivoria, lagoa, estiagem.ABSTRACT: Feeding ecology of Astyanax lacustris (Osteichthyes: Characidae) from Lagoa do Piató, Assu, Rio Grande do Norte, Brazil. This study reports on the stomach content analyses of the Astyanax lacustris captured on a monthly basis from Lagoa do Piató, Assu, Rio Grande do Norte, Brazil, during the period of September, 2006 to August, 2007. The fish were captured using gillnets of 4 cm mesh size. The total length, standard length, body mass and stomach weight were registered for each fish. The stomach contents analyses of 360 fishes were carried out based on volumetric method, points, frequency of occurrence and applying the Relative Importance Index. The degrees of repletion of the stomachs were determined and the Repletion Index was calculated. The diet variations and frequency of ingestion were related to the rainfall and limnological parameters. The food items identified were separated into distinct groups according to their origin. It is concluded that this species shows an omnivorous feeding habit with a tendency towards insectivory, with intensive feeding during the dry season. The concentration of dissolved oxygen was more closely related to.feeding activity than the rainfall and the other physico-chemical factors of the water.

Espectro alimentar e variação sazonal da dieta de Espectro alimentar e variação sazonal da dieta de Espectro alimentar e variação sazonal da dieta de Espectro alimentar e variação sazonal da dieta de Plagioscion Plagioscion Plagioscion Plagioscion squamosissimus squamosissimus squamosissimus squamosissimus (Heckel, 1840) (Osteichthyes, Sciaenidae) na lagoa (Heckel, 1840) (Osteichthyes, Sciaenidae) na lagoa (Heckel, 1840) (Osteichthyes, Sciaenidae) na lagoa (Heckel, 1840) (Osteichthyes,

This study aimed to estimate the biomass and energy of a clonal planting short rotation experiment with hybrids of Eucalyptus urophylla ST Blake x Eucalyptus grandis (Hill) Maiden, deployed in 3 m x 3 m spacing, at the Academic Unit Specialized in Agricultural Sciences, Macaíba/RN. The analysis were performed at the Laboratory Panels and Wood Energy, Federal University of Viçosa, in which the following ratings on wood three cultivars (GG100 ; AEC0144 and AEC0224) were performed: determination of basic density, high calorific power, chemical analysis, thermogravimetric analysis and subsequent calculations for estimating the mass production and energy were performed. The base (10 cm from the ground), the third and two thirds of commercial tree height: composed for analysis, taken from three points along the stem samples were used. The design of the experiment was a completely randomized. Data were subjected to analysis of variance and the means were compared by Tukey test (a= 0.05). The clone who excelled in the first year of planting was the GG100 with 11,805 kW.h.ha-1 of energy productivity, followed by clone AEC0224 (6,755 kW.h.ha-1) and AEC0144 (4,405 kW.h.ha-1). The performance of this clone was due to mainly the higher volumetric growth. The wood quality among clones showed little difference. It should stimulate the deployments of species of short rotation in the state of RN to supply the elevated energy demand of forest biomass in the region.

The macaúba palm (Acrocomia aculeata) is a palm-seed-oil producing tree of great economic value for its high productivity, and the broad range of possible uses for the different parts of the plant. This palm is one of the most promising species for the production of biodiesel, however, its use generates large amounts of waste. The aim of this work is to produce and evaluate the quality of briquettes made from the epicarp of the macaúba palm, in association with the waste of the Pinus sp. For the characterization of the residues, the following analyses were carried out: bulk density, immediate chemical composition, and higher calorific value. Different treatments were adopted in the production of the briquettes, namely: T1 (100% macaúba palm), T2 (75% macaúba palm + 25% pine), T3 (50% macaúba palm + 50% pine), T4 (25% macaúba palm + 75% pine) and T5 (100% pine). The briquettes were produced at a pressure of 1000 PSI, and at a temperature of 120-130 ºC, press and cooling times of 5 minutes, and an average humidity of 9.88% for the macaúba palm and 8.00% for the Pinus. In order to qualify the briquettes’ dimensions, the following were evaluated: apparent density, rupture load, lower calorific value, useful calorific value and energy density. In general, mixing at least 50% macaúba epicarp is recommended to produce briquettes, as this material provides increased strength and energy density to the product.

This study analyzed the reproductive biology of Prochilodus brevis held captivity during ontogenetic development in order to contribute to the conservation and improvements to induced breeding of this specie, which stands out for having commercial value attributed to the consumption of his "ova" and to be endemic in the Northeast. Sampling was fortnightly and 137 specimens were analyzed. Observations macroscopic and microscopic of the gonads allowed the identification of four stages of gonadal maturation: Immature, In Maturation, Mature and Regression. The age at maturity was predicted with a satisfactory degree of confidence, because the gonadal development was observed from fingerlings until adulthood. Hatching of fingerlings was accompanied at Estevão de Oliveira Fishery Station, in Caicó/RN/Brazil. Later the fingerlings were transferred to a tank in the Agricultural School of Jundiaí in Macaíba/RN/Brazil. Were verified juvenile males and females up to 225 days post-hatching (dph), in maturing stage from 247 dph, individuals with mature gonads from 274 dph and in regression stage from 359 dph for females and 410 dph for males, being corroborated by the variation in the curve of maturation based on the values of the Gonadosomatic Index. Thus, it was observed that even in captivity P. brevis reaches all stages of gonadal maturation, except for spawning, due to the absence of appropriate environmental conditions, since it is a species rheophilic. Therefore, it was found that the maturation of P. brevis occurs between 247 and 340 dph, corresponding to the period from October to January, similar to the natural environment.

RESUMO. O estudo analisou o desenvolvimento embrionário do curimatã Prochilodus brevis, espécie endêmica do nordeste brasileiro, pertencente à família Prochilodontidae (Characiformes). Os embriões foram obtidos da Estação de Piscicultura Estevão de Oliveira (DNOCS -Caicó, RN, Brasil). Após inseminação artificial dos reprodutores, foram realizadas coletas dos embriões, em intervalos de uma hora até a eclosão dos alevinos. As amostras foram fixadas em formol a 10%, a partir do qual os embriões foram analisados quanto aos padrões morfológicos externos, bem como em líquido Bouin por 12 horas, para análises histológicas. Os ovos de P. brevis são esféricos, transparentes e não adesivos. O período embrionário da espécie foi definido pelas fases de zigoto, clivagem, mórula, blástula, gástrula, organogênese, eclosão e larva, descritos por quatorze horas à temperatura de 28ºC. Os padrões morfo-embrionários identificados se mostram similares aos de outras espécies de peixes teleósteos, no entanto, com variações relacionadas à cronologia de cada fase. A caracterização do desenvolvimento embrionário de P. brevis, proveu informações úteis no estabelecimento e adequação das condições de cultivo. Palavras-chave:Embriogênese, reprodução, aquicultura, biologia do desenvolvimento, curimatã.ABSTRACT. The study analyzed the stages of the embryonic development of the curimatã Prochilodus brevis, endemic fish of the northeast Brazilian, belonging the family Prochilodontidae (Characiformes). The embryos were obtained of the Estação de Piscicultura Estevão de Oliveira (DNOCS -Caicó, RN, Brazil). The collections were accomplished after the beginning of the spawning and fertilization of the oocytes, in intervals of one hour to the appearance of the larvae. The samples were fixed in 10% formaldehyde for morphological analysis and in Bouin's solution during a period of twelve hours, after they were processed through routine histological techniques. The eggs of P. brevis are spherical, transparent and non-adhesive. The main events reported during embryogenesis were: zygote, cleavage, morula, blastula, gastrula, organogenesis, hatching and larvae. These events are common to several species of teleost fish, the variation found are related to the chronology of each phase and the specific characteristics of oocytes and eggs. The characterization of the embryonic development of fish such as P. brevis, it is essential to suit the growing conditions to the biological needs of these animals. The data from this study agree with studies of species endemic to the northeastern region and expand the possibilities for their cultivation.

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Our study aims to determine the energetic quality of residues from the manufacturing of jatropha and eucalyptus, as well as to evaluate the physical properties of the briquettes made with different proportions of these biomasses. The following proportions were used for this study: 100% eucalyptus; 75% eucalyptus; 50% jatropha and 50% eucalyptus; 75% jatropha; and 100% jatropha. The apparent density of the residues, the immediate chemical product, the highest calorific value (HCV), the apparent density, the energy density, the usable calorific value (UCV), the lowest calorific value (LCV), the breaking strength of the briquettes (FR) and the hydroscopic moisture balance (HMB) were verified. Although the energetic characteristics of the jatropha residues are not superior to those of eucalyptus, this biomass adds favorable mechanical characteristics to the briquettes comprised of greater proportions of jatropha to eucalyptus, guaranteeing the energetic properties of the briquette, as well as reducing the production cost.