Indicadores zootécnicos e econômicos da tilapicultura em tanques-rede de diferentes dimensões

The present study aimed to compare the main zootechnical and economic indicators of farming tilapia in superintensive system developed in two different net cages dimensions: 6 and 18 m(3). Were used 12,960 juveniles male reversed Nile tilapia (Oreochromis niloticus), strain supreme, with an initial average weight of 32.0 g (+/- 0.85) for 6 m(3) net cages and 88.5 g (+/- 0.96) for 18 m(3) net cages. The fish were fed three times a day with commercial extruded ration, crude protein levels from 40 to 32%, particle size from 2 to 8 mm and daily feeding rate starting with 8% of live weight (LW), decreasing up to 1% LW. It was conclued that, although no statistical difference in most indicators zootechnical (P>0.05), the production of tilapias in bigger net cages resulted in lower average total cost and higher rentability per kg of fish produced, 34.4% higher, resulting in better profitability.

Respostas hematológicas em tuvira após anestesia com diferentes concentrações de óleo de cravo

The hematological responses in tuvira (Gymnotus aff. inaequilabiatus) after clove oil anesthesia at different concentrations were evaluated in this study. Fish (n = 25) with average length of 26.8 +/- 2.4 cm and weighing 94.4 +/- 23.6 g were separated in five groups composed with five animals each and submitted individually to respective concentrations of clove oil: 40, 80, 120, 160 and 200 mg L-1. After anesthetic recuperation, the blood samples collection were performed, as well as complete hemogram. The results were submitted to analysis of variance, Tukey test (P<0.05) and Sperman's correlation analysis. There was an increase (P<0.05) on hematocrit, red blood cells count, thrombocytes count and in the values of neutrophils with increasing of clove oil concentrations. In addition, positive correlation (P<0.05) were observed on total leukocytes, as well as negative linear correlation (P<0.05) for mean corpuscular hemoglobin concentration (MCHC). The clove oil anesthesia on tuvira cause hematological changes with an effect dose-dependent. These changes should be considered mainly in future studies designed to establish the reference values of hematologic variables for this specie.

Mortality Risk in Insects

Understanding how and why insect numbers fluctuate through time and space has been a central theme in ecological research for more than a century. Life tables have been used to understand temporal and spatial patterns in insect numbers. In this study, we estimated cause-of-death probabilities for phytophagous insects using multiple decrement life tables and the irreplaceable mortality analytic technique. Multiple decrement life tables were created from 73 insect life tables published from 1954 to 2004. Irreplaceable mortality (the portion of mortality that cannot be replaced by another cause) from pathogens, predators, and parasitoids was 8.6 +/- 7.2, 7.8 +/- 4.9, and 6.2 +/- 1.6%, respectively. In contrast, the mean irreplaceable mortality from all non-natural enemy mortality factors (mortality from factors other than natural enemies) was 35.1 +/- 4.4%. Irreplaceable mortality from natural enemies was significantly lower compared with non-natural enemy factors. Our results may partially explain cases of unsuccessful efficacy in classical biological control, after successful establishment, by showing low irreplaceable mortality for natural enemies, including 5.2 +/- 1.6% for introduced natural enemies. We suggest that the environment (i.e., the degree of environmental stability) influences the magnitude of the irreplaceable mortality from natural enemies. Our results lead to several testable hypotheses and emphasize that it is not possible to estimate the effect of any mortality factor without considering its interaction with competing mortality factors, which has far-reaching consequences for population biology and applied ecology.

ACUTE TOXICITY and ENVIRONMENTAL RISK of OXYTETRACYLINE and FLORFENICOL ANTIBIOTICS TO PACU (Piaractus mesopotamicus)

The oxytetracyline (OTC) and florfenicol (FLO) are the most used antibiotics for bacterial disease control in fish. The aims are: estimating the lethal concentration 50% initial (LC(I) 50;48h) of OTC (Terramicina (R)) and FLO (Aquaflor (R)) for pacu (Piaractus mesopotamicus); classifying OTC and FLO according to the acute toxicity and the risk of environmental intoxication; and assessing OTC and FLO dilution effect in water quality variables. Fish were acclimatized for 10 days in a bioassay room at 27 +/- 2 degrees C. Then nine animals (three each concentration) were exposed to 7.0; 7.5; 8.0 or 8.5 mg L(-1) of OTC or to 600.0; 700.0; 800.0; 900.0 and 1000.0 mg L(-1) of FLO and a control treatment. The water quality variables recorded daily were: pH, temperature, electric conductivity, and dissolved oxygen. OTC and FLO were classified according to acute toxicity and environmental risk. The estimated OTC LC(I) 50;48h for pacu is 7.6 mg L(-1) and the estimated FLO is > 1000 mg L(-1). OTC reduced the dissolved oxygen concentration, and it was considered moderately toxic, causing risk of environmental intoxication to pacu. FLO is not toxic; it does not cause risk of environmental intoxication to pacu and does not change water quality variables.

Eficácia do paration metílico e do extrato aquoso de folhas secas de nim no controle de anacanthorus penilabiatus (monogenoidea) em pacu (piaractus mesopotamicus)

This work determined the efficacy of the insecticide methyl parathion and the natural pesticide azadirachtin present in the aqueous extract of dry neem leaves (AEDNL) to Anacanthorus penilabiatus (Monogenoidea) control in pacu (Piaractus mesopotamicus). The efficacy of methyl parathion was evaluated in an experiment consisting of six treatments (0.0, 3.0, 4.0, 5.0, 6.0 and 7.0 mg methyl parathion/L water) and five exposure times (2, 4, 8, 16 and 24 h). The efficacy of azadirachtin present in AEDNL was assessed in an experiment consisting of seven treatments (0,0; 25; 50; 75; 100; 125; e 150 mL/L water) and five exposure times (24, 48, 72, 96 and 120 h). The efficacy of methyl parathion increased with increasing concentration and exposure time. The highest control efficacy was obtained with a concentration of 7 mg methyl parathion/L at all exposure times. In this treatment, the highest efficacies were observed at 16 and 24 h of exposure, with a control rate of 96.2 and 97.0%, respectively. For the AEDNL, the highest control efficacy (89.2%) was obtained with a concentration of 2.9 mg/L after 120 h of exposure. The efficacy in the treatments employing 1.47 and 1.18 mg/L was 83.9 and 82.5%, respectively, after 120 h of exposure. Methyl parathion presented a higher efficacy in the control of A. penilabiatus than the AEDNL. The AEDNL was moderately effective in the control of the parasite.

Aeromonas spp. Em água de pisciculturas da região da baixada ocidental Maranhense

Among the widely distributed bacterial agents in the aquatic ecosystem, can be outstanding the family Aeromonadaceae detected such in fish as in the water of this system. This study intended to verify the occurrence of Aeromonas spp. in pond water of fishfarms located in Occidental Lowland Region of Maranhao. Twelve properties located in Pinheiro, Palmeirandia and Perimirim cities had been selected. The harvest of the samples occurred in the period from October, 2008 to March, 2009. A total of 48 pond water samples were harvested. Four water samples of each fishfarm. Aeromonas were confirmed in 100% of the samples. The 89 isolate identified had been classified in three species, A. hydrophila (88%), A. caviae (9%), A. veronii sobria (3%). The pond waters of the fishfarms analyzed presented contamination with potentially pathogenic species of aeromonas which represents risk for people's health, especially for the organisms cultivated in these properties.

Canibalismo em larvas de matrinxã, Brycon cephalus, após imersão dos ovos à diferentes concentrações de triiodotironina (T3)

The present work evaluated larvae cannibalism of matrinxa, Brycon cephalus, originated from eggs exposed to triiodothyronine, in the period of 36 to 72 hours after hatching. Observed parameters were: weight and length of larvae, stomach content, presence of cannibalism and type of attacks. This study was carried out at Centro de Pesquisa e Gestao de Recursos Pesqueiros Continentais (CEPTA/IBAMA), Pirassununga-SP, in November 2004. Three females were hormonally induced to spawn and pooled oocytes were fertilized and separated into four batches that constituted the treatments: L-1 (control - water); L-2 (0.01 ppm T-3); L-3 (0.05 ppm T-3) and L-4 (0.1 ppm T-3). Eggs were exposed during 15 minutes to water or to solutions containing the different concentrations of T3. Eggs were distributed in 12 conic incubators (60 L), with three replicates per treatment. There was stocked 500 mL of eggs per incubator and hatched larvae were counted. Samples of 30 larvae per treatment were colleted during occurrence of cannibalism (36, 48, 60 and 72 hours post hatching). Predator larvae (with rests of larvae in the stomach) were 50% of the total number of larvae and they presented weight 50% higher compared to that of non predator larvae (without rests of larvae in the stomach) and 9% higher regarding length. Coefficient of variation of weight and length did not differ among treatments, showing similarity in relation to the size. The stomach content revealed that cannibalism occurred in around 50-60 % of larvae, regardless the exposure to the triiodothyronine, and attacks were characterized as head-tail and tail-head attacks.

Controle biológico de Dolops carvalhoi (Crustacea: Branchiura) em juvenis de pacu (Piaractus mesopotamicus)

This work evaluated piaucu juveniles (Leporinus macrocephalus) efficiency on the control of Dolops carvalhoi in pacu (Piaractus mesopotamicus) under artificial infestation. 30 fish were equally distributed in six aquarium and acclimated for seven days. After this period the pacus were unnaturaly infested with 20 D. carvalhoi per fish to four days. on the fifth day, for aquaria were added with five uninfected piaucus each and the fish were checked eight times to evaluted the total number of parasites in fish body and aquarium wall. After 24 hours in the aquarium with piaucus the total number of Dolops was significant lower than only pacus suggesting that piaucu preyed the parasite. The parasite number was reduced 15 minutes after the addition of piaucus and after 24 hours, no parasites was found in pacu body and aquarium walls, suggesting that piaucu fingerling may be used to branchiurans infestations in other species of fish.

Análise de efluente e histologia da pele, fígado e rim de Pacus (Piaractus mesopotamicus) suplementados com cromo trivalente

The objective of this work was to evaluate the skin, liver and kidney histology of young pacus supplemented in diet with trivalent chromium and to evaluate the residue of chromium in water effluent. Randomised delineation by using factorial scheme 4x2, with four levels of chromium (0, 6, 12, 18 mg/L), two stocking densities (4 and 20 kg/m(3)), and four repetitions were used. Pacus with 100 g were used, for 90 days. An increase of the number of mucus cells and club cells in the epidermis of the pacus supplemented with 18 chromium mg/kg was observed in any stocking density. The same effect was observed in the liver, and in the highest density (20 kg/m(3)) the alterations already occurred at the level of 6 mg/kg with the inclusion of chromium, initially with congestion of sinusoids and getting worse at the level of 18 mg/kg with necrosis. The kidney didn't present visible morphologic alterations when supplemented and submitted to the stocking densities. The concentration of chromium in the effluent of pacus was 3.27 mu g/L in the higher level of supplementation (18 mg/L). In conclusion the level of 18 supplement mg/kg was not shown beneficial to the growth of pacus and the stocking density, due to the possible stress, accelerated the alteration histology process of tissues.

Histopatologia do intestino de Pseudoplatystoma fasciatum (osteichthyes, pimelodidae) parasitados com cestodas proteocefalídeos e nematodas

This work describes intestine histopathology of Pseudoplatystoma fasciatum infected by endohelminths. Nineteen specimens were caught from Aquidauna River, Mato Grosso do Sul State, in October 2005 and submitted to necropsy, when intestine of each specimen was fixed with AFA solution during 12 h. Soon after, samples were immersed in buffered formalin and 24 h after, transferred to alcohol 70%. Study of histology sections was made to 5; m and stained with haematoxylin and eosin. It showed structures displaying helminths encapsulated by connective tissue in intestinal muscle with fibroplasy in several stages of capsule development. Were observed focus of necrosis in intestinal mucous and sub-mucous and helminthes cut obliquely in intestinal lumen. In addition, there was discreet mucous desquamation, associated to basal membrane thickness.

Efeito do probiótico Bacillus subtilis no crescimento, sobrevivência e fisiologia de rãs-touro (Rana catesbeiana)

The probiotics are live microorganisms, in latency state, that benefices the development of the animals. The objective of this work was to evaluate the effect of the Bacillus subtilis in different doses about the growing, survival and immunological and hematological analyses in the Bullfrog (Rana catesbeiana) froglets. The test was developed in Experimental Frog farm of Agriculture Department, Pindamonhangaba, SP. Three doses of probiotics were tested (T1 - 2.5 g/Kg, T2 - 5 g/Kg and T3 - 10 g/Kg of food). The test was carried out with three simultaneous replicates, plus control group. The products were added to froglet's diet and mixed to the meal. The animals were previously feed with this diet for a period of 14 days and accompanied for about 42 days after metamorphose. Biometrics were performed every 7 days. It was evaluated the final weight, the survival, phagocytic capacity, phagocytic index and hematological analyses as hematocrit, hemoglobin level, erythrocyte number, absolute indices hematimetrycs (MCV and MCHC), differential counting of leucocytes and total counting of leucocytes and trombocytes. The results had shown that the doses of the probiotics had produced none effect on the final weight and survival. The immunological analyses had shown that the probiotics have presented immunostimulator effect, but haven't influenced the hematological parameters of the animals.

Influência da incorporação de vitamina C à dieta no desempenho produtivo de rãs-touro Lithobates catesbeianus pós-metamorfoseadas

The experiment was developed in Marta Farm, Tremembe city, located in the State of São Paulo - Brazil, using a frogculture commercial project. The aim of this study was evaluate the performance (growth, survival and feed conversion) of bullfrogs Lithobates catesbeianus, post-metamorphosed fed with diets containing different amounts of vitamin C and your performance with the temperature. The animals were kept in 24 boxes of (2.0 x 1.0 m) with an initial density of 50 animals per square meter. We tested the following levels of supplementation in the diet: 0, 250, 500, 750, 1,000 and 2,000 mg vitamin C kg(-1) of diet. The experimental design was completely randomized with six treatments and four replicates. The parameters evaluated were: feed intake, weight gain, feed conversion and survival tax. The animals were weighed at the beginning of the experiment and every 30 days and recorded daily to room temperature. The percentage of food intake decreased with the growth of the frogs, from 3.85 to 1.2% of the live weight, and the mean of temperature decreased from 28 to 20.1 degrees C. It was concluded that there was no influence of vitamin C on the performance (growth, survival and feed conversion) of bullfrogs in the growing stage.

Estrutura genética de populações de melhoramento de Pinus caribaea var. Hondurensis por meio de marcadores microssatélites

O Pinus caribaea var. hondurensis Barret & Golfari tem elevada importância como espécie comercialmente plantada; aproximadamente 1,8 milhões de hectares estão ocupados por plantios desta espécie no Brasil. O trabalho teve como objetivo verificar por meio de marcadores microssatélites a variabilidade genética em Pinus caribaea var. hondurensis, bem como sua manutenção durante o processo de melhoramento genético, dentro de uma população- base de melhoramento, uma população de matrizes selecionadas e uma população melhorada F1. Para a realização das análises foi necessária a transferência de primers desenvolvidos para locos microssatélites de outras espécies do gênero. Dos 20 pares de primers testados, 8 foram transferidos para a espécie (RPS 25b, RPS 150, PSM 2, PR 4.6, PtTX 2037, PtTX 3029, RPTest 01 e RPTest 09). Verificou-se a existência de endogamia entre e dentro das populações estudadas, e o maior valor observado entre as populações foi F ST = 0,0213 (população base e F1). A heterozigosidade média observada e a heterozigosidade esperada na população-base foram, respectivamente, H0 = 0,2469 e He = 0,2489. A maior distância genética (D = 0,0119) foi observada entre as populações-base e a população melhorada F1. Através da distância genética entre as matrizes, foram indicados 10 cruzamentos potenciais entre as matrizes mais contrastantes, almejando a obtenção de vigor de híbrido nas progênies obtidas a partir destes cruzamentos.

New Culture Medium to Xanthan Production by Xanthomonas campestris pv. campestris

Xanthan is a important biopolymer for commercial purpose and it is produced in two stages by Xanthomonas campestris. In the first one, the bacterium is cultivated in the complex medium enriched in nitrogen and the biomass produced is used as inoculum for the next stage in which the gum is produced in another medium. In this work a new medium for the first stage is proposed in place of currently used YM medium. Different formulated growth media were studied and the correspondent biomass produced was analysed as inoculum for the second stage. The inoculum and gum were produced by batch process in shaker at 27A degrees C in pH 6.0 and at 30A degrees C in pH 7.0, respectively. The gum was precipitated with ethanol (3:1 v/v). The dryed biomass and xathan gum produced were determined by drying in oven at 105 and 40A degrees C, respectively. The viscosity of the fermentation broth and 1% gum solution in water were determined in Brookfield viscometer. The formulated medium presented the increase in gum production (30%), broth (136%) and 1% gum solution viscosity (60%) compared to YM, besides the inferior cost. The results showed the importance of the quality of the inoculum from the first stage of the culture which influenced on the gum viscosity in the second stage.