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Natural food available in ponds can complement formulated feed in fed aquaculture. This study elucidated the natural food intake and its contribution to tambaqui (Colossoma macropomum) growth in fertilized and unfertilized ponds, using stable isotope and stomach contents analyses. Additionally, it described the impact of fertilization management on natural food availability, fish performance, and production costs. Tambaqui juveniles (93.8 ± 15.0 g) were stocked (0.55 fish/m2) in fertilized (Fert) and unfertilized (NoFert) ponds (600 m2) for a culture period of 10 months in quadruplicate. A lower food conversion ratio was observed in Fert ponds. The main natural food items ingested by tambaqui were insects, vegetables, and cladocerans. Plankton contributed 39.4% and 10.7% of muscle formation in Fert and NoFert ponds, respectively. Pond fertilization (2.45 g of nitrogen and 0.80 g of phosphorus per square meter every two weeks) did not significantly affect fish growth, survival, or productivity but had a slightly influence on water quality parameters. However, fertilization increased the zooplankton density (through phytoplankton) in the water, thereby increasing autochthonous food availability for tambaqui consumption. This species demonstrates the ability to alternate between natural food sources and commercial feed without compromising its development. Consequently, tambaqui exhibits suitability for farming within restorative and integrated aquaculture systems as well as intensive systems reliant on commercial feed. [ABSTRACT FROM AUTHOR]

Natural food available in ponds can complement formulated feed in fed aquaculture. This study elucidated the natural food intake and its contribution to tambaqui (Colossoma macropomum) growth in fertilized and unfertilized ponds, using stable isotope and stomach contents analyses. Additionally, it described the impact of fertilization management on natural food availability, fish performance, and production costs. Tambaqui juveniles (93.8 ± 15.0 g) were stocked (0.55 fish/m2) in fertilized (Fert) and unfertilized (NoFert) ponds (600 m2) for a culture period of 10 months in quadruplicate. A lower food conversion ratio was observed in Fert ponds. The main natural food items ingested by tambaqui were insects, vegetables, and cladocerans. Plankton contributed 39.4% and 10.7% of muscle formation in Fert and NoFert ponds, respectively. Pond fertilization (2.45 g of nitrogen and 0.80 g of phosphorus per square meter every two weeks) did not significantly affect fish growth, survival, or productivity but had a slightly influence on water quality parameters. However, fertilization increased the zooplankton density (through phytoplankton) in the water, thereby increasing autochthonous food availability for tambaqui consumption. This species demonstrates the ability to alternate between natural food sources and commercial feed without compromising its development. Consequently, tambaqui exhibits suitability for farming within restorative and integrated aquaculture systems as well as intensive systems reliant on commercial feed.

Heavy metal Zinc is still a pollutant from various industrial and domestic activities whose waste is directly dumped into the waters. The presence of biota in the waters can be used as a bioindicator to identify the presence of heavy metal contaminants. The kinetics of the Zinc bioaccumulation process through the freshwater route using pomfret (Colossoma macropomum) and sepat fish (Trichogaster trichopterus) as bioindicators have been investigated by analyzing the effect on variations in concentration and pH. This research was conducted by determining Zinc speciation's effect and concentration on the bioaccumulation process. The results showed an increase in concentration would also increase the rate of uptake and elimination rate of Zinc by pomfret and sepat, obtained concentration factors (CF) at variations of Zinc concentration in pomfret was 2.56 - 22.97 mL.g-1 and 2.14 - 56.87 mL.g-1 in sepat fish. While the value of the concentration factor (CF) in the variation of pH for pomfret is 0.65 - 13.15 mL.g-1 and for sepat fish is 0.93 - 15.29 mL.g-1, and ZnCl42- was the dominant species containing Zn in most of the electrolytes in fresh water and from each concentration variation. This method is expected to provide information that can be used for environmental studies and against toxic effects for food safety. [ABSTRACT FROM AUTHOR]

Acanthocephalans are endoparasites of several vertebrate species. These parasites are able to attach the host intestine, which culminates in low nutrient utilization and severe economic losses. This review discusses the impact of acanthocephalosis for aquaculture and demonstrates promising control and treatment measures against this parasitosis. Echinorhynchus truttae was considered one of the main parasites affecting salmonids; however, there are currently no scientific data on relevant outbreaks of this parasitosis. It is emphasized that, currently, the disease caused by Neoechinorhynchus buttnerae in tambaqui Colossoma macropomum is the fish acanthocephalosis with the strongest impact, besides being one of the most important acanthocephalosis affecting animal production worldwide. It has been noted that this disease has direct correlation with an environment replete with contaminated zooplankton and biosafety failures. Amongst revised synthetic chemotherapeutics, carbon tetrachloride and loperamide are described as being strongly efficient against E. truttae, and levamisole has been the most studied molecule for N. buttnerae. Considering the demand for alternative molecules, studies have shown that thyme, garlic and peppermint are promising against acanthocephalans. It must be emphasized a great need for standardization of in vitro and in vivo tests, as well as the need for studies on pharmacokinetics and pharmacodynamics. As prospects to control acanthocephalosis, we highlight the need for development of innovative aquaculture environments (biofloc and recirculation systems) that can prevent or extinguish the intermediate host, new methods of drug inclusion in the diet and genetic studies aiming improvement of resistant fish lineage and even the genome description of the parasite. [ABSTRACT FROM AUTHOR]

Inputs, outputs, and accumulation of phosphorus were evaluated for monoculture and polyculture grow‐outs of the Amazon river prawn, Macrobrachium amazonicum and tambaqui, Colossoma macropomum in stagnant earthen ponds using a hypereutrophic water source. A completely randomized experiment was designed with four treatments and three replications: prawn monoculture—monoculture with 30 prawns/m2, fish monoculture—monoculture with 3 fish/m2, integrated multitrophic aquaculture (IMTA)—polyculture with 30 prawns/m2 and 3 fish/m2 reared free swimming, and POLY‐CAGE—polyculture with 30 prawns/m2 and 40 fish/m3 reared in net cages. Samples of commercial diet, water, rain, animals, accumulated sludge, total suspended solids, and settleable solids were collected throughout the experiment to determine the total phosphorus contents of the inputs and outputs and to calculate the phosphorus budget. Results showed high variability in the phosphorus content of each variable in all treatments. Much of the phosphorus was accumulated as solid material at the bottom of the pond (ca. 31–73%). The integrated grow‐outs showed the best phosphorus conversion from the commercial diet (ca. 24–34%) and phosphorus use efficiency from all inputs (ca. 12–18%). Bioturbation from both species appeared to influence the liberation of phosphorus to the water column, stimulating plankton productivity and promoting the turnover of nutrients. A mud‐feeder species should be added to the IMTA systems to take advantage of the large amounts of nutrients in the bottom sediments and increase the uptake of phosphorus by the farmed species. [ABSTRACT FROM AUTHOR]

The tambaqui Colossoma macropomum is the most important native fish in Brazilian aquaculture. Females are almost 20% heavier than males and therefore are more profitable. Based on this information, we tested four different concentrations (20, 40, 80, and 120 mg/kg diet) of oestradiol (E2) offered during 6 weeks to tambaqui larvae and analysed their efficiency in producing female monosex batches of the species. The study was performed in two independent tests, using different genetic backgrounds (broodstocks). All treatments increased the percentage of females in the population, but only the highest E2 dose was "free" of males in both tests. All treated groups contained intersex individuals (when sex inversion is not complete). Plasmatic E2 concentration was similar between treated and non‐treated fish 60 days after the treatment in fish treated with 20, 40, and 80 mg E2/kg diet. However, tambaqui treated with a 120 mg E2/kg diet showed lower E2 plasma concentration in comparison with the control group. Last, we chlorinated the water to ensure the environmental integrity of the study. Three days after chlorination, the water was completely free of any oestradiol residue (analysed by high‐performance liquid chromatography). [ABSTRACT FROM AUTHOR]

Abstract: The South American continent is known for its high production and exports in fisheries and aquaculture, but has not reached its full potential in fish farming. The latest data on fish production in Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Uruguay and Venezuela were explored in this review. Aspects of biology, production, market and health of the species most produced in South America are described in detail. These species include the round fish (Colossoma spp., Piaractus spp. and hybrids) and catfish (Pseudoplatystoma spp. and hybrids), in addition to the promising pirarucu Arapaima gigas, yellowtail tetra Astyanax altiparanae and silver catfish Rhamdia quelen. Among the countries mentioned, Chile and Brazil are two of the largest intensive fish producers in the world. Chile relies primarily on marine fish, whereas Brazil is prominent for continental production. Special emphasis is given to the black pacu Colossoma macropomum because it is a commonly farmed fish in South American countries and offers several desirable productive characteristics (domesticated, omnivorous and easy to reproduce). Furthermore, this fish has the greatest potential to compete economically with tilapia production in South America. The production of native fish is currently overtaking the production of exotic species in some countries, which is considered a milestone for South American aquaculture. Regarding diseases, the main pathogens are similar to those observed throughout the world, such as Ichthyophthirius multifiliis, different species of monogeneans and trichodinids, and the bacteria Aeromonas hydrophila. Local pathogens, such as the parasites Perulernaea gamitanae and Goezia spinulosa, are also concerning. [ABSTRACT FROM AUTHOR]

The effects of dietary calcium chloride (CaCl2) concentration on the growth, survival, moulting and body composition of Astacus leptodactylus were studied. Diets were prepared using supplementation of 0 (control), 30, 60 and 120 g kg−1 calcium chloride commercial trout larvae diet containing 50% protein and 12% lipid. Astacus leptodactylus larvae with an average total length of 22.0 ± 0.05 mm ( TL) and weight of 0.53 ± 0.01 g obtained from eighteen ovigerous females collected from Seydisehir Sugla Dam lake in Konya, Turkey, were stocked in 0.2-m2 aquariums at a rate of 50 crayfish m−2 and reared for 90 days. The experiments included four treatments (diets) with three replicates each. Calcium chloride exerted positive effects on growth, moulting frequency, feed efficiency and survival of narrow-clawed crayfish. Crayfish fed with 60 g calcium kg−1 calcium chloride-supplemented diet exhibited the highest weight gain and specific growth rate ( SGR) but the lowest survival rate (63.3%) ( P < 0.05). There were no significant differences ( P > 0.05) in mean moisture (803.5 g kg−1) and protein content (177.0 g kg−1) in crayfish tail meat. However, lipid values were between 3.8 and 11.6 g kg−1 and significantly different among the diets ( P < 0.05). Diet with 60 g kg−1 calcium chloride is recommended for the best growth of freshwater crayfish. [ABSTRACT FROM AUTHOR]

An economical and efficient approach to reduce the impact of P discharge by aquaculture industry is to adjust the P level in fish feeds to the precise nutrient requirement at different growth stages in a digestible nutrient basis. However, P requirement seems to be species specific and affected by several physiological, dietary and environmental factors. Based on the importance of tambaqui ( Colossoma macropomum) to Latin American aquaculture, we designed a 63-day trial to evaluate the effect of available P ( AP) levels on growth, nutrient digestibility, haematology and blood biochemical parameters, carcass proximate composition and bone mineralization. Quadruplicate groups of tambaqui juveniles (144 ± 2.0 g) were fed five isonitrogenous (278 g kg−1 digestible protein) and isocaloric (13.5 Mj DE kg−1) diets containing graded AP levels (3.0, 5.6, 7.5, 9.1 and 11.0 g kg−1) following a completely randomized design. Dicalcium phosphate ( DCP) was used as the main P source. No mortalities and signs of P deficiency were observed among the dietary treatments. A remarkably high P digestibility was observed in all plant-based diets with a tendency of decreasing P digestibility with the increase in total P levels. Tambaqui seems to be able to grow well without inorganic P supplementation during the trials; however, this species required 7.0 g AP kg−1 diet for proper bone mineralization. P supplementation had a limited effect on haematology and blood biochemistry of tambaqui. Ecological implications of natural feeding habit and evolutionary position of this species are further discussed, and new hypothesis are drawn based on our results. [ABSTRACT FROM AUTHOR]

Climate change and species invasions interact in nature, disrupting biological communities. Based on this knowledge, we simultaneously assessed the effects of climate change on the native distribution of the Amazonian fish Colossoma macropomum as well as on its invasiveness across river basins of South America, using ecological niche modeling. We used six niche models within the ensemble forecast context to predict the geographical distribution of C. macropomum for the present time, 2050 and 2080. Given that this species has been continuously introduced into non-native South American basins by fish farming activities, we added the locations of C. macropomum farms into the modeling process to obtain a more realistic scenario of its invasive potential. Based on modelling outputs we mapped climate refuge areas at different times. Our results showed that a plenty of climatically suitable areas for the occurrence of C. macropomum occurrence are located outside the original basins at the present time and that its invasive potential is greatly amplified by fish farms. Simulations of future geographic ranges revealed drastic range contraction in the native region, implying concerns not only with respect to the species conservation but also from a socio-economic perspective since the species is a cornerstone of artisanal and commercial fisheries in the Amazon. Although the invasive potential is projected to decrease in the face of climate change, climate refugia will concentrate in Paraná River, Southeast Atlantic and East Atlantic basins, putting intense, negative pressures on the native fish fauna these regions. Our findings show that short and long-term management actions are required for: i) the conservation of natural stocks of C. macropomum in the Amazon, and ii) protecting native fish fauna in the climate refuges of the invaded regions. [ABSTRACT FROM AUTHOR]

In vivo and in vitro antiparasitic activity of the essential oil of Lippia sidoides and blood and histological alterations were assessed in Colossoma macropomum (tambaqui). Essential oil concentrations of 10, 20, 40, 80, 160 and 320 mg/L were assayed in vitro against monogenoideans Anacanthorus spathulatus , Notozothecium janauachensis and Mymarothecium boegeri from fish gills. Lippia sidoides essential oil concentrations of 320 and 160 mg/L were 100% effective against monogenoideans in 10 min and 1 h of exposure, respectively. However, the effectiveness of 100% concentrations of 80 mg/L and 40 mg/L occurred in 3 and 6 h, respectively. In the in vivo tests, juvenile fish were submitted to 60 min of baths with 10 mg/L and 15 min of baths with 20 mg/L of the essential oil of L. sidoides . These therapeutic baths were not efficient against Ichthyophthirius multifiliis , and monogenoideans present in the gills of C. macropomum . In addition, 10 and 20 mg/L of the essential oil of L. sidoides caused an anesthetic effect on the fish and did not influence total glucose and protein plasma levels; however, it decreased the number of total erythrocytes in fish exposed to the higher concentration of this essential oil. Severe alterations and irreversible damage were observed in the fish gills just after L. sidoides essential oil baths and after 24 h of recovery. The most recurrent lesions found were hyperplasia and fusion of the lamellar epithelium, vasodilation, detachment of the gill epithelium and lamellar aneurism, epithelial breakdown with hemorrhage, congestion, edema and necrosis, proliferation of the mucous cells and chloride cells and lamellar hypertrophy. Therefore, since the essential oil of L. sidoides has in vitro antiparasitic activity and low concentrations of it have shown toxic effects, the bioactive potential of its main chemical components should be investigated, as well as more efficient forms of its administration in therapeutic baths in order to eliminate fish parasites. [ABSTRACT FROM AUTHOR]

Un experimento fue conducido para evaluar los efectos de cinco niveles de proteína (25,27, 29, 31 y 33%) sobre el comportamiento productivo de alevinos de la gamitana, Colossoma macropomum Cuvier 1818, alimentados con dietas isocalóricas (2,7 kcal de ED/g). Los parámetros medidos fueron ganancia de peso (GP), conversión alimenticia (CA), proteína retenida (PR), razón de eficiencia proteica (REP) y energía retenida (ER). En la preparación de las dietas experimentales se utilizaron como fuentes de proteína harina de anchoveta y harina de torta de soya y como fuentes de energía maíz amarillo duro, subproducto de trigo y aceite de pescado. Se encontraron diferencias significativas (P

Lufenuron is a benzoylurea insecticide that interfere in chitin synthesis in insects. Although lufenuron is widely used in agriculture and aquaculture, rare are studies described that relates to possible toxic effects in fish. This work aimed to evaluate acute and chronic toxic effects of benzoylurea pesticide (lufenuron) on biological parameters of Colossoma macropomum (Tambaqui). In the acute test, juveniles of Tambaqui were divided into control group and five experimental groups with exposure from 0.1 to 0.9 mg/L of lufenuron for 96 h. Animals were also submitted to chronic toxicity test for four months in concentrations of 0.1 and 0.3 mg/L of lufenuron, the concentration used in the treatment of ectoparasites in fish and 50% of LC 50 96 h, respectively. The presence of hemorrhages was observed in eyes, fins and operculum of fish exposed to 0.7 and 0.9 mg/L of lufenuron. Histological analysis showed changes in the morphology of fish gills submitted to acute toxicity test, as lamellar aneurysm and blood congestion inside lamellae. Lufenuron promoted damage in fish retina as in ability to respond to stimuli in photoreceptors and in ON-bipolar cells in acute test. In chronic test, blood glucose analysis and morphometric parameters showed no significant differences (p > 0.05). In general, Tambaqui exhibited behaviors associated with stress when exposed to lufenuron. Thus, lufenuron showed several toxic effects in relation to biological parameters in Tambaqui. This concerns about the use and discard of lufenuron, and indicates the requirement of environmental actions to prevent potential contamination of aquatic biota. [ABSTRACT FROM AUTHOR]

Hybrid fish production has increased, leading this sector to occupy a prominent place in the regional and national economy. Thus, the present study aimed to develop a Quality Index Method for gutted ice-stored hybrid tambatinga ( Colossoma macropomum × Piaractus brachypomum ) and estimate its shelf life. Twelve assessors were selected to develop and validate the QIM protocol, and microbiological and physicochemical analyses were performed every other day for 28 days of storage. The final protocol was composed of five quality attributes divided into 10 parameters, with 18 demerit points. Based on the microbiological and physicochemical results, the shelf life of gutted ice-stored hybrid tambatinga is 10 days. [ABSTRACT FROM AUTHOR]

Summary: This short review will focus on the nutritional requirement of tambaqui (Colossoma macropomum) and pirapitinga (Piaractus brachypomus), two important aquacultured neotropical fishes for Latin American countries. Demonstrated is that despite the large number of studies on protein requirement for C. macropomum, most are inadequate. The principal difficulties with the various published papers are described. Using the nutritional ecology of the fish, some recommendations are presented to identify future research needs in the area. A focus on determining the nutrient requirement for P. brachypomus is featured since there are few studies regarding this species, as well as a focus on the differences in feeding plasticity with C. macropomum. Market and farming constraints and the nutritional ecology of these species in Latin America with special emphasis on Brazil, are also described. [ABSTRACT FROM AUTHOR]

O objetivo desta nota foi avaliar o efeito do volume do tanque-rede na produtividade de juvenis de tambaqui durante a recria. Juvenis de tambaqui foram criados por 60 dias, na densidade de 300 peixes/m³, em tanques-rede de dois diferentes volumes: 1 e 6 m³. Foram avaliados parâmetros de crescimento e de produtividade final. Não houve diferença no crescimento em peso e em comprimento. O coeficiente de variação do comprimento foi significativamente menor para os peixes do tanque-rede pequeno. A sobrevivência, produção por volume e o ganho de peso não diferiram entre os tratamentos. Os peixes do tanque de maior volume foram significativamente mais eficientes na conversão alimentar. A recria pode ser realizada em tanques dos dois volumes testados sem prejuízo zootécnico para o criador.The goal of this note was to evaluate the effect of cage volume on the productivity of juvenile tambaqui during second growth phase. Tambaqui juveniles were raised for 60 days on a density of 300 fish/m³, in two different volumes cage: 1 and 6 m³. We evaluated growth and productivity parameters. There are no differences in fish weight and length. The coefficient of variation of length was significantly lower for fish in the small volume cage. There was no differences in survival, volume production, and weight gain between treatments. Fish from the larger volume cage were significantly more efficient in food conversion. The second growth phase may be undertaken in both cage volumes without losses to fish farmers.

Transposable elements (TEs) are DNA sequences that have the ability to move and replicate within the genomes. TEs can be classified according to their intermediates of transposition, RNA (retrotransposons) or DNA. In some aquatic organisms, it has been observed that environmental factors such as pH, temperature and pollution may stimulate differential transcription and mobilization of retrotransposons. In light of this information, the present study sought to evaluate the expression of Rex6 TE transcripts in Colossoma macropomum, which is a very commercially exploited fish in Brazil. In order to establish a comparative analysis using real-time PCR, the samples were collected from Amazonian rivers with different physical and chemical characteristics (distinguished by clear water and black water). Quantitative RT-PCR analyses revealed a differential pattern of expression between tissues collected from different types of water (clear and black waters). When it came to the hepatic and muscle tissues sampled, the levels of Rex6 transcripts were significantly different between the two Amazonian water types. These results suggest that environmental conditions operate differently in the regulation of Rex6 transcription in C. macropomum, results which have implications in the reshaping of the genome against environmental variations. [ABSTRACT FROM AUTHOR]

The article offers information on a research to compare and define the normal cross-sectional gross and computed topographic (CT) anatomy for the fish pacu to gain insight into the use of advanced diagnostic imaging for future clinical cases. Topics discussed include reasons for choosing pacu in the experimental design, comparison of frozen cross sections of the fish with transverse images of cadaver fish, and anatomic detail for future research and clinical investigation provided by images.

In this study was evaluated the fatty acids composition of tambaqui (Colossoma macropomum) fillet, fish species cultivated in Roraima State, Brazil. For the extraction of tambaqui oil was used Sohxlet device and then it was methylated. The oil was identified using a gas chromatograph and were identified 24 acids and these were divided into characteristic groups such as: saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA) and series fatty acids omega-6 and omega-3. The ratios obtained were PUFA/SFA and omega-6/omega-3. The results of chromatographic analysis were subjected to tests by variance ANOVA and multiple comparisons of Tukey at 5%. The ratios omega-6/omega-3 and PUFA/SFA showed values of 8.58 and 0.75 respectively. [ABSTRACT FROM AUTHOR]

Tambaqui Colossoma macropomum is the most important Amazonian native species in South American aquaculture. Innate immunity at least partially depends on the recognition of pathogen-associated molecular patterns by receptor-recognizing pathogens (PRRs). Some PRRs have been characterized in fishes, and several studies have focused on the role of lectins in the immune system of various fishes. Lectins are proteins that specifically recognize carbohydrates and which have important biological functions. Tambaqui serum lectin (ComaSeL), which was identified on the basis of its hemagglutinating activity, was pre-purified, biochemically characterized, and used in assays of antibacterial activity against pathogenic bacteria in freshwater fishes. A study of the seasonality of this lectin was performed. Comasel activity was stable at a pH between 4.0 and 9.0 and lost 100 % of its activity at 70 °C. It recognized the carbohydrates d-galactose, 1- O-methyl- d-galactopyranoside, and d-fucose, showing antibacterial activity for Gram-negative bacteria. Its activity showed significant differences between the summer and winter ( p < 0.05, Tukey test), thereby corroborating observations that tambaqui becomes more susceptible to mortality from diseases caused by bacteria and fungi during the winter. With this information, new tools may be developed for gaining a better understanding of the role of these proteins in the immune system of the tambaqui, ultimately resulting in the improved management of this fish by pisciculturists. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: There is an increasing demand for intensive care in hospitals, which can lead to capacity limitations in the intensive care unit (ICU). Due to postponement of elective surgery or delayed admission of emergency patients, outcome may be negatively influenced. To optimize the admission process to intensive care, the post anaesthesiacare unit (PACU) was staffed with intensivist coverage around the clock. The aim of this study is to demonstrate the impact of the PACU on the structure of ICU-patients and the contribution to overall hospital profit in terms of changes in the case mix index for all surgical patients. Methods: The administrative data of all surgical patients (n = 51,040) 20 months prior and 20 months after the introduction of a round-the-clock intensivist staffing of the PACU were evaluated and compared. Results: The relative number of patients with longer length of stay (LOS) (more than seven days) in the ICU increased after the introduction of the PACU. The average monthly number of treatment days of patients staying less than 24 hours in the ICU decreased by about 50% (138.95 vs. 68.19 treatment days, P <0.005). The mean LOS in the PACU was 0.45 (± 0.41) days, compared to 0.27 (± 0.2) days prior to the implementation. The preoperative times in the hospital decreased significantly for all patients. The case mix index (CMI) per hospital day for all surgical patients was significantly higher after the introduction of a PACU: 0.286 (± 0.234) vs. 0.309 (± 0.272) P <0.001 CMI/hospital day. Conclusions: The introduction of a PACU and the staffing with intensive care staff might shorten the hospital LOS for surgical patients. The revenues for the hospital, as determined by the case mix index of the patients per hospital day, increased after the implementation of a PACU and more patients can be treated in the same time, due to a better use of resources. [ABSTRACT FROM AUTHOR]

The article discusses the analysis of the infestation rate in Colossoma macropomum, hybrid tambacu (C. macropomum x Piaractus mesopotamicus) and hybrid tambatinga (C. macropomum x Piaractus brachypomum) with Perulernaea gamitanae from two fish farms in Amapá State, Brazil. Inflammation and fibrous nodules were observed on the attachment sites of the parasites. There was higher intensity of P. gamitanae in tambacu and tambatinga, but its intensity was moderate.

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To determine the digestible lysine requirement for pacu juveniles, a dose–response feeding trial was carried out. The fish (8.66 ± 1.13 g) were fed six diets containing the digestible lysine levels: 6.8, 9.1, 11.4, 13.2, 16.1 and 19.6 g kg−1 dry diet. The gradual increase of dietary digestible lysine levels from 6.8 to 13.2 g kg−1 did not influence the average values of the parameters evaluated ( P > 0.05). The increase of dietary digestible lysine level to 16.1 g kg−1 significantly improved weight gain (WG), specific growth rate (SGR), protein productive value (PPV), protein efficiency rate (PER), and apparent feed conversion rate (FCR), but was not different from fish fed diets containing 19.6 g kg−1 lysine. Fish fed diets containing 16.1 and 19.6 g kg−1 digestible lysine showed lower body lipid contents than fish in the other treatments. The digestible lysine requirement as determined by the broken-line model, based on average WG values, was 16.4 g kg−1. The other essential amino acid requirements were estimated based on the ideal protein concept and the value determined for lysine. [ABSTRACT FROM AUTHOR]

Tambaqui, Colossoma macropomum, were fed with three vitamin C levels and two iron levels for 21 d: Diet 1 without vitamin C and with 30 mg of iron/kg; Diet 2 with 100 mg of vitamin C and 30 mg of iron/kg; and Diet 3 with 100 mg of vitamin C and 300 mg of iron/kg. Mortality was not observed during the feeding experiment. There were no changes in hematological parameters in fish that were fed the different diets. Iron contents in liver, muscle, and plasma were significantly different in fish fed with different iron content in the diets; when associated with vitamin C, changes were observed only for plasma iron. Therefore, tambaqui exhibits varied iron absorption in response to different levels of iron with and without vitamin C, a conclusion consistent with findings for other species of fish. [ABSTRACT FROM AUTHOR]

Seed dispersal is a critical stage in the life history of plants. It determines the initial pattern of juvenile distribution, and can influence community dynamics and the evolutionary trajectories of individual species. Vertebrate frugivores are the primary vector of seed dispersal in tropical forests; however, most studies of seed dispersal focus on birds, bats and monkeys. Nevertheless, South America harbors at least 200 species of frugivorous fishes, which move into temporarily flooded habitats during lengthy flood seasons and consume fruits that fall into the water; and yet, we know remarkably little about the quality of seed dispersal they effect. We investigated the seed dispersal activities of two species of large-bodied, commercially important fishes ( Colossoma macropomum and Piaractus brachypomus, Characidae) over 3 years in Pacaya-Samiria National Reserve (Peru). We assessed the diet of these fishes during the flood season, conducted germination trials with seeds collected from digestive tracts, and quantified fruit availability. In the laboratory, we fed fruits to captive Colossoma, quantified the proportion of seeds defecated by adult and juvenile fish, and used these seeds in additional germination experiments. Our results indicate that Colossoma and Piaractus disperse large quantities of seeds from up to 35% of the trees and lianas that fruit during the flood season. Additionally, these seeds can germinate after floodwaters recede. Overexploitation has reduced the abundance of our focal fish species, as well as changed the age structure of populations. Moreover, older fish are more effective seed dispersers than smaller, juvenile fish. Overfishing, therefore, likely selects for the poorest seed dispersers, thus disrupting an ancient interaction between seeds and their dispersal agents. [ABSTRACT FROM AUTHOR]

Abstract: This study evaluated the effect of paraquat (PQ) and temperature on hematological parameters and nonspecific immune system of fish Colossoma macropomum (Cachama). Juveniles were used for all experiments. Fish were exposed to three temperatures (18, 28, 35°C) and 10mg/L PQ during 21 days (PQ LC50 96h was of 48.05mg/L). Hematological (Hb, Ht, VCM, HCM and CHCM and RBC) and immunological parameters (WBC, differential count of white cells, phagocytes, and bacterial killing by phagocytes) were analyzed for 7, 14 and 21 days. Fishes PQ exposed at 18°C decreased Hb, MCH and MCHC; we observed sickle erythrocytes in control group at 18°C, and in PQ-exposed groups at 18 and 35°C. Immunological parameters were not affected by temperature. Neutrophils decreased significantly in all PQ-exposed groups. Bacterial killing by phagocytes decreased in 18 and 35°C PQ-groups; a synergistic interaction was shown between PQ and temperature on WBC and lymphocytes. These results indicate that PQ affected neutrophils counts independently of temperature exposure; the temperature exerted a synergistic effect on PQ toxicity in lymphocyte counts and phagocytic response and besides nonspecific immune response, PQ and temperature affects hematological parameters such as Hb, MCH, MCHC and erythrocytes morphology. [Copyright &y& Elsevier]

The article discusses a study which examines the histopathological changes in the gill, kidney and liver of pacu (Piaractus mesopotamicus) exposed to different levels of trichlorfon in Brazil. Trichlorfon is an organophosphate pesticide. It is the most frequently used products against parasites in farmed fish. A toxicity assay was used to examine the lethal effects of trichlorfon. Histological analysis of the tissues was also performed. Low concentrations of trichlorfon were found to be toxic to pacu.

To facilitate economical culture of black pacu, Colossoma macropomum, and red pacu, Piaractus brachypomus, in the Amazon region of South America, we assessed locally available alternative energy sources for practical diets. We tested the effects of control diets (containing wheat products) versus diets with different Amazonian feedstuffs (yucca, Manihot sculenta, plantain, Musa paradisiaca, or pijuayo, Bactris gasipaes) on the performance of the pacus in three feeding trials. Black pacu (22.5 ± 0.03 g; Trial 1) or red pacu (2.56 ± 0.01 g; Trial 2) were fed diets containing 30% wheat bran (control) or cooked or uncooked yucca, plantain, or pijuayo for 12 wk. In Trial 3, larger black pacu (86.9 ± 6.4 g) were grown to market size in 24 wk on similar diets. Weight gain, feed conversion, survival, alternative complement activity, and lysozyme were similar among diets. Hepatosomatic index, liver glycogen, and dry matter were affected by diet in Trials 1 and 2, but effects were not consistent among trials. In Trial 3, protein efficiency ratio was lower in fish fed the diet containing wheat middlings. However, relative to wheat bran or wheat middlings, all feedstuffs tested were effective energy sources for juvenile black pacu and red pacu. [ABSTRACT FROM AUTHOR]

Estimation of the apparent digestibility coefficient ADC(%) of C3 and C4 plants in experimental diets for fingerlings of tambaqui ( Colossoma macropomum, Cuvier, 1818) was calculated by applying chromic oxide (Cr2O3) external marker methodology and by a proposed mathematical expression based on the isotopic composition ( δ13C). A total of 240 tambaqui fingerlings each weighing ±48.2 g and measuring ±9.8 cm were maintained in eight 500-L aquariums specially designed for faeces collection. The ADC(%) of the C3 and C4 diets did not differ significantly between the two methods, producing results of 75.6%; 76.2% and 74.4%; 72.8%, respectively. The ADC(%) results obtained by isotopic method presented less variation than by chromic oxide. The proposed mathematical expression for calculating the ADC(%) based on δ13C values offers an alternative methodology, which can reduce errors and diminish the effort required to collect biological material. However, it is important to note that this method is limited to analysis of diets or food items with distinct isotopic signals. [ABSTRACT FROM AUTHOR]

Tambaqui Colossoma macropomum (Cuvier) is a fish of primary importance in Amazon aquaculture. It has been described as an acid-resistant species that moves seasonally between white (muddy) water and black water rivers and enters the extremely dilute acidic areas of flooded jungle to feed during the rainy season. To analyse the pH tolerance of this species, tambaqui were exposed to three water pH levels for 40 days (pH 4.0, 6.0 and 8.0). The water was acidified slowly over 3 h, allowing the fish to acclimate. A similar protocol was used to adjust water pH to 8.0. No mortality was observed during the exposure period. Several haematological parameters were significantly changed in alkaline-exposed animals, with significant decreases in haematocrit (20%), haemoglobin concentration (8%) and red blood cells (12%). Tambaqui showed severe blood variations when exposed to alkaline pH. Fish final weight, condition factor and specific growth rate (SGR) was inversely proportional to a pH increase, and SGR were higher for fish reared in acidic water. The relative insensitivity of tambaqui to low pH confirms its acid tolerance and is in accordance with its natural occurrence in black water habitats. [ABSTRACT FROM AUTHOR]

No abstract available. [ABSTRACT FROM AUTHOR]

The present study examined the role of branchial and orobranchial O2 chemoreceptors in the cardiorespiratory responses, aquatic surface respiration (ASR), and the development of inferior lip swelling in tambaqui during prolonged (6 h) exposure to hypoxia. Intact fish (control) and three groups of denervated fish (bilateral denervation of cranial nerves IX+X (to the gills), of cranial nerves V+VII (to the orobranchial cavity) or of cranial nerves V alone), were exposed to severe hypoxia (PwO2=10 mmHg) for 360 min. Respiratory frequency (fR) and heart rate (fH) were recorded simultaneously with ASR. Intact (control) fish increased fR, ventilation amplitude (VAMP) and developed hypoxic bradycardia in the first 60 min of hypoxia. The bradycardia, however, abated progressively and had returned to normoxic levels by the last hour of exposure to hypoxia. The changes in respiratory frequency and the hypoxic bradycardia were eliminated by denervation of cranial nerves IX and X but were not affected by denervation of cranial nerves V or V+VII. The VAMP was not abolished by the various denervation protocols. The fH in fish with denervation of cranial nerves V or V+VII, however, did not recover to control values as in intact fish. After 360 min of exposure to hypoxia only the intact and IX+X denervated fish performed ASR. Denervation of cranial nerve V abolished the ASR behavior. However, all (control and denervated (IX+X, V and V+VII) fish developed inferior lip swelling. These results indicate that ASR is triggered by O2 chemoreceptors innervated by cranial nerve V but that other mechanisms, such as a direct effect of hypoxia on the lip tissue, trigger lip swelling. [ABSTRACT FROM AUTHOR]

This study quantified the accumulation of nitrogen (N) in the water column, sediments, fish and seepage water during a production cycle ofColossoma macropomum. By combining estimates of the deposition rates of uneaten feed, faeces and dead phytoplankton with measurements of N accumulation in the sediment, the rate of decomposition of organic matter in the sediment was estimated. The first-order rate constant for organic matter decomposition was 0.237±0.019 day−1. Total N recovery during the first weeks of the experiment was about 65%. Later, the N recovery was close to 100%. The cumulative recovery at the end of the experiment was almost 100%, meaning that the N budget in the system studied can be fully explained without consideration of N volatilization, due to either denitrification or ammonia volatilization. In the beginning of the growth cycle, the major flux of N was sedimentation. Intensive microbial degradation process occurred about 3–4 weeks later, leading to a release of inorganic N and an approach towards a steady state as to the accumulation of organic N. Feed was irregularly applied during the experiment but fish growth was constant, showing that the fish utilized detrital or planktonic feed during periods of low feeding. Nitrogen accumulated in the pond during periods of excessive feeding and was utilized by the fish during periods of low feeding. This cycling should be further studied and may be an important pond management technique. [ABSTRACT FROM AUTHOR]

Juvenile tambaqui, Colossoma macropomum, were exposed to sulfide and hypoxia for 12, 24, 48 and 96 h. Hemoglobin concentrations, red blood cell counts, and mean cell hemoglobin, were higher at 12 h in fish exposed to hypoxia. However, control fish and those exposed to sulfide and hypoxia had lower red blood cell count, hemoglobin concentration and hematocrit at 96 h. Methemoglobin was higher than in the controls, probably due to the hypoxemia induced by these stressors. Sulfhemoglobin was not detected in significant amounts in the blood of fish exposed to sulfide (in vivo), yet hemoglobin converted into sulfhemoglobin at 1–15 mM sulfide in vitro. Anaerobic metabolism seemed to be an important mechanism for adapting to sulfide exposure and blood pH returned to control values after 24 h of sulfide, preventing acidosis. The high sulfide tolerance in tambaqui is associated with its high tolerance to hypoxia. [ABSTRACT FROM AUTHOR]

Pacu, Piaractus mesopotamicus (=Colossoma mitrei), is a South American warm water fish species found in the temperature range of 15–35°C. The culture of a warm water species in temperate regions demands knowledge on its temperature requirements. Pacu introduction into the Israeli fish culture system is being considered. Temperature range in the region is 8–33°C, thus the minimum winter water temperatures might be a limiting factor. To determine what is the minimum temperature pacu would tolerate, and hence which overwintering operations in warm-temperate regions are required for this warm water species, low temperature tolerance tests in the laboratory and observations in the field were carried out. Laboratory experiments reducing temperature by 1–3°C per day were carried out with fish of 150–200 g, about the size pacu reach after one culture season. The field observations compared survival of two-year-old pacu of 1.3 kg mean weight overwintered in outdoors and in greenhouse ponds. For one-year-old fish 7.5°C was found to be the lower temperature tolerance limit. Two-year-old fish withstand short exposures to this temperature rather well and their lower tolerance limit might be lower. This indicates that in warm-temperate regions pacu should survive in outdoors ponds. In this case some loss of weight should be expected, and suspension of feeding when temperature drops below 16–18°C is recommended to avoid wasting feed that the fish will not consume anyway. To be in the safe side, inflow of the warmest available water into the ponds is recommended if maximum water temperature drops to 10°C or below. Overwintering in greenhouses or other heated facilities would be recommended if an exceptionally cold winter is expected and for regions with lower winter minimum temperatures. [ABSTRACT FROM AUTHOR]

RID=""ID="" Correspondence to: J. Cunha Bastos http://link.springer.de/link/service/journals/00128/bibs/0064002/00640191.htm [ABSTRACT FROM AUTHOR]

Feeding trials with juvenile Colossoma macropomum Cuvier (approximately 40g) were carried out to study their protein requirements and their efficiency in metabolizing vegetable protein. Two groups of diets were used. In one group, the crude protein consisted exclusively of fish protein concentrate. In the second group the protein consisted of a mixture (55:45) of vegetable and animal protein without fish meal. In each group 30 and 50% protein levels were used. The highest weight increase (1.64%/day) and the lowest feeding rate were obtained with the 50% protein fish meal free diet. During the trial all fish accumulated visceral fat while body protein content decreased and dry matter increased. There was a high correlation between liver weight and liver glycogen. The highest amounts of liver glycogen were induced by diets containing fish meal and/or low protein content. In contrast lo visceral fat deposits, accumulated liver glycogen was of less significance for surviving starvation periods. The activity of digestive enzymes depends on both stomach and gut fullness. Trypsin activity, contrary to pepsin, was correlated with diet protein content, α-amylase activity was not correlated with diet composition. [ABSTRACT FROM AUTHOR]

Juvenile, 0.87 g Colossoma macropomum (Cuvier) were submitted to different ad libitum feeding regimes. Feeding frequency ranged from one to five meals per day and intervals between meals from 3 h to 24 h. Higher feeding frequencies resulted in higher feed uptake, a higher growth rate and a decreased feed utilization efficiency. Feed consumption was lower at 0700 h than at 1900 h. The amount of feed from different meals persisting in the digestive tract was determined with chromic-oxide-marked feed. This method revealed that with ad libitum feeding, about 21% of the feed remained uneaten. Feed losses did not differ significantly between feeding regimes. Feed accumulated in the digestive tract in the morning and early afternoon. In the late afternoon most feed rests disappeared from the digestive tract and feed consumption increased. It is suggested that feed uptake and growth of C. macropomum can be improved by extending the feeding period after 1900 h. [ABSTRACT FROM AUTHOR]

Trials on induced breeding of the native Amazonian fish tambaqui, Colossoma macropomum (Cuvier), using CPE and HCG treatments, were carried out during 1992–93 at the Fish Culture Station in Natal, Brazil. Final maturation, ovulation and spermiation of tambaqui broodstock, reared in earthen ponds, were induced by injecting heteroplastic carp pituitary gland extracts (CPE) and human chorionic gonadotrophin (HCG) separately. The female spawners received double injections and the males received a single dose. Females were tranquillized using quinaldine and their genital openings were sutured before the resolving injection was administered. Latent period between the resolving injection and ovulation varied from 6 to 11 h according to the prevailing water temperature. Milt was obtained by extrusion. Stripping and dry fertilization of the eggs produced viable larvae. Relative fecundity was estimated at 140 000 eggs kg-1. Mean fertilization and hatching rates varied from 50% to 70% and from 60% to 80%, respectively. [ABSTRACT FROM AUTHOR]

Este trabalho avalia a importância da pesca do tambaqui (Colossoma macropomum) nas bacias dos rios Amazonas e Orinoco e, mais especificamente, na região do médio Solimões. As análises foram baseadas em dados de literatura e da pesca praticada pela frota de Tefé no médio Solimões, coletados no mercado de Tefé, entre 1991 e 1995, e a bordo de embarcações da frota pesqueira comercial, entre 1994 e 1995. A importância relativa da espécie pode alcançar 21% da produção de pescado em alguns centros urbanos da bacia do Orinoco, na Venezuela; 8% da Amazônia peruana; e 35% da Amazônia boliviana. No Brasil, na região do rio Madeira, a importância relativa do tambaqui subiu de 10% em 1977 para 32% entre 1984 e 1989. Em Manaus, a espécie já respondeu por 44% do pescado desembarcado. Porém, a proporção de tambaqui desembarcado nesta cidade sofreu uma grande diminuição nos anos 80 e 90, chegando a representar apenas 2,5% do total desembarcado. No médio Solimões, região apontada como a principal área de pesca para esta espécie, são utilizados diversos tipos de aparelhos e explorados diferentes habitats, de acordo com a flutuação do nível da água dos rios. A pesca do tambaqui nesta região é realizada principalmente em lagos, através de malhadeira e rede de cerco, incidindo sobre peixes jovens (