Xilanase e β-glucanase na digestibilidade aparente de nutrientes do triticale pela Tilápia-do-nilo

Avaliou-se o efeito de diferentes níveis do composto enzimático Natugrain Blend L®, que contém endo-xilanase e endo-beta-glucanase, sobre a digestibilidade dos nutrientes e a energia do triticale pela tilápia-do-nilo. O método para a determinação da digestibilidade foi o indireto, utilizando-se o óxido de crômio III (0,10%). O delineamento experimental foi inteiramente ao acaso, com cinco tratamentos e três repetições. O nível de substituição da dieta-referência foi 50,0% pelo triticale. Os tratamentos foram 0,0; 150,0; 300,0; 450,0 e 600,0mg kg-1 de Natugrain Blend L, que contém 800 unidades g-1 de endo-1,3(4)-β-glucanase (BGU) e 36.600 unidades g-1 de endo-1,4-β-xylanase (EXU). Os coeficientes de digestibilidade aparente foram: da matéria seca, 76,42; 74,01; 83,39; 82,97 e 78,34%; da proteína bruta 88,19; 88,39; 90,52; 92,05 e 88,34%, da energia bruta 75,93; 71,31; 81,78; 80,27 e 78,62%, respectivamente, para os níveis de inclusão na dieta 0,0; 150,0; 300,0; 450,0 e 600,0mg kg-1 de Natugrain Blend L.Os resultados demonstram que 300mg kg-1 do complexo de enzimas foi suficiente para aumentar o coeficiente de digestibilidade aparente da matéria seca. O composto de enzimas pode ser utilizado para aumentar a eficiência de aproveitamento dos nutrientes do triticale.

Cultivation of Rubrivivax gelatinosus in fish industry effluent for depollution and biomass production

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relação lisina digestível: proteína digestível em rações para tilápias-do-nilo

This study was carried out to determine the best digestible protein/digestible lysine ratio that should be present in feed fed to Nile tilapias. Two hundred and sixteen tilapias (11.0 +/- 0.43g) were distributed in 36 fish tanks (205 L) at a density of 6 fish/tank. Twelve feeds were formulated with three different digestible protein (DP) levels 22.0; 26.0 and 30.0% (based on digestible amino acids) and four different lysine percentages of 4.5; 6.0; 7.5 or 9.0% in relation to digestible protein. The fish were fed ad libtum during a 60-day period. There was significant effect of the digestible protein and digestible lysine ratio on weight gain, because the increase in lysine levels in feeds with 26 and 30% DP promoted linear increase in this parameter. The best values for feed conversion were obtained at the levels 26 and 30% DP that increased the daily consumption of digestible protein. The lysine level caused a linear reduction in feed conversion and linear increase in the protein efficiency rate. The results suggested that the 26% DP level might be used in ration to feed Nile tilapia juveniles; however, these should contain digestible amino acids and the digestible lysine/digestible protein ratio should be 6.0%. However, for levels higher than 26% DP, a maximum digestible lysine level of 7.5% DP improved weight gain for the species.

Níveis de proteína digestível e energia digestível em dietas para tilápias-do-nilo formuladas com base no conceito de proteína ideal

This study was carried out to determine the best digestible energy and digestible protein ratio in feeds for Nile tilapia (Oreochromis niloticus) juveniles 30.0 +/- 4.21 g) based on digestible amino acids and the ideal protein concept). Twelve rations were formulated with protein levels 22.0; 26.0; 30.0 and 34.0% of digestible protein and levels 3,000, 3,300 and 3,600 kcal/kg digestible energy. The digestible energy/digestible protein ratio was between 8.94 and 15.19 kcal/g. Three hundred and twenty four tilapias were randomly distributed in thirty six 250 L circular tanks at a density of 9 fish/tank, a total of 12 treatments with three replications. After 60 days, there was no significant difference in weight gain, daily weight gain and feed conversion ratio among the studied treatments. A linear increase was observed in fillet yield with increasing digestible protein. With respect to feed cost/kg weight gain, the treatment with 30.0% DP and 3,000 kcal/kg DE presented low cost and better cost effectiveness index. Therefore, it was concluded that digestible energy did not influence the productive performance parameters and that effective feeds can be formulated with DP levels lower than 34% when feeding juvenile tilapias. The ration should be formulated based on the concept of ideal protein.

Valor nutritivo de macrófitas aquáticas flutuantes (Eichhornia crassipes, Pistia stratiotes e Salvinia molesta) utilizadas no tratamento de efluentes de aqüicultura

The aim of this study was to evaluate the nutritive value of free-floating aquatic macrophytes, Eichhornia crassipes (Mart.) Solms (Pontederiaceae), Pistia stratiotes (L.) (Araceae) and Salvinia molesta (Mitchell) (Salviniaceae) used in a Nile tilapia (Oreochromis niloticus) waste treatment, and these species biomass potential uses. The vegetal biomass samples were collected from 0.25 m 2 floating squares and divided in aerial and submerse parts, to determine the concentrations of cell wall fraction, soluble carbohydrates, polyphenols, lipids, crude protein and total phosphorus. The higher nutritive value was observed in E. crassipes and S. molesta aerial parts, and in P. stratiotes total biomass, due to their lower cell wall fraction mean rates (60.7; 64.2 and 56.9 % dry mass, respectively) and to the higher rates of: crude protein (10.1; 9.1 and 8.8 % dry mass, respectively), soluble carbohydrates (26.6; 18.7 and 12.4 mg.g -1 dry mass, respectively) and lipids (7.6; 4.5 and 4.4% dry mass, respectively). It may be concluded that P. stratiotes total biomass, and E. crassipes and S. molesta aerial biomass have nutritive values with potential use for ruminant feeding or as ration ingredients.

Anesthesia of fish with benzocaine does not interfere with comet assay results

Fish blood erythrocytes are frequently used as sentinels in biomonitoring studies. Usually, fish blood is collected by painful cardiac or caudal vein punctures. Previous anesthesia could decrease animal suffering but it is not known at present whether anesthesia can cause confounding effects. Therefore, using the alkaline single cell gel (SCG)/comet assay with blood erythrocytes of the cichlid fish Nile tilapia, we tested for a possible modulation of induced DNA damage (methyl methanesulfonate; MMS) by the anesthetic benzocaine administered by bath exposure (80mg/l for ∼10min). Furthermore, benzocaine (80-600mg/l) was tested for its genotoxic potential on fish erythrocytes in vitro and for potential interactions with two known genotoxins (MMS and hydrogen peroxide). Our results did neither indicate a significant increase in the amount of DNA damage (even after a 48h follow-up), nor indicated interactions with MMS-induced DNA damage when fish were exposed to benzocaine in vivo. There was also no increase in DNA damage after in vitro exposure of fish erythrocytes to benzocaine. Clear concentration-related effects were observed for the two genotoxins in vitro, which were not significantly altered by the presence of benzocaine. These results suggest that anesthesia of fish does not confound comet assay results and the use of blood samples from anesthetized fish can be recommended with regard to animal welfare. © 2002 Elsevier Science B.V. All rights reserved.

Fauna parasitária de peixes oriundos de pesque-pague do município de Guariba, São Paulo, Brasil

This study describes the occurrence and the seasonality of parasites of cultivated fish from a fee fishing farm located in Guariba, São 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.

First record of chilodonella hexasticha (ciliophora: Chilodonellidae) in brazilian cultured fish: A morphological and pathological assessment

Chilodonelids are small ciliated protozoans found worldwide and can be dangerous in culture conditions. This study presents morphometric data on the ciliate Chilodonella that is found in cultured Nile tilapia (Oreochromis niloticus), native bait fish tuvira (Gymnotus aff. inaequilabiatus) and native pacu (Piaractus mesopotamicus) and includes a histopathological assessment of the changes that occur in the pacu. For parasitic diagnosis, skin and gill samples were scraped onto slides, dried at room temperature, stained with Giemsa or impregnated with silver nitrate, and the measurements were obtained from photomicrographs. In the diseased pacu, the first gill arch was collected and fixed in a 10% buffered formalin solution for histopathological analysis. Parasite specimens from the different collection sites were identified morphologically as C. hexasticha Kiernik (1909). Diseased fish exhibited depigmentation, skin ulceration, scale loss, excessive mucus production and gill lesions. Histopathological analysis of pacu gills displayed epithelial proliferation with mononuclear inflammatory infiltrate, hemorrhages, and scattering necrosis. In Brazilian-farmed fish this is the first record of C. hexasticha, which has great pathogenic potential in cultured freshwater species. In addition, two new hosts are presented. © 2012 Elsevier B.V.

Red Light Stimulates Feeding Motivation in Fish but Does Not Improve Growth

Nile tilapia fish were individually reared under similar light levels for 8 weeks under five colored light spectra (maximum wavelength absorbance): white (full light spectrum), blue (~452 nm), green (~516 nm), yellow (~520 nm) or red (~628 nm). The effects of light on feeding, latency to begin feeding, growth and feed conversion were measured during the last 4 weeks of the study (i.e., after acclimation). We found that red light stimulates feeding, as in humans, most likely by affecting central control centers, but the extra feeding is not converted into growth. © 2013 Volpato et al.

Avaliação ecotoxicológica e risco ambiental dos inseticidas utilizados no controle da larva de Aedes aegypti para Daphnia magna, Lemna minor e peixes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hematologia e ecotoxicidade do teflubenzuron no controle de Trichodina sp. em peixes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Suplementação alimentar com ácidos graxos essenciais para tilápias do Nilo: desempenho produtivo, hematológico e granuloma por corpo estranho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desempenho produtivo e crescimento muscular de linhagens de tilápia-do-nilo cultivadas na fase inicial

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Retenção do cátion do sulfato de cobre nos compartimentos biótico e abiótico de mesocosmos com sistema de fluxo contínuo de água

Pós-graduação em Aquicultura - FCAV

Efeito da privação de ninho sobre a agressividade e o sucesso de acasalamento em machos de tilápia do Nilo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)