Digestibility and gastrointestinal transit of Ulva fasciata seaweed meal in tilapia (Oreochromis niloticus) juveniles: basis for the inclusion of a sustainable ingredient in aquafeeds

The seaweed Ulva fasciata has many features favorable to integrated multi-trophic aquaculture (IMTA). It is efficient at biofiltering, shows high biomass production, and is rich in many nutrients useful in aquatic animal diets. We evaluated the digestibility of the seaweed meal of U. fasciata produced in IMTA and its effects on gastrointestinal transit time in tilapia (Oreochromis niloticus) juveniles. Juveniles (6.30 ± 1.80 g initial weight, and 5.5 ± 0.61 cm initial length) were cultivated in six tanks (50 individuals per tank) in a closed recirculating aquaculture system. The digestibility of Ulva meal was 57.92 ± 5.21% for dry material, 78.59 ± 1.91% for protein, and 69.87 ± 3.72% for energy. The inclusion of 10% seaweed meal did not alter the gastrointestinal transit time in tilapia juveniles as compared to controls. The earliest colored feces were observed four hours after first feeding in both treatments (feed diets with [10%] and without seaweed); all fecal material was colored after ten hours. The digestibility of seaweed meal was satisfactory for dry material, protein, and gross energy, and the inclusion of 10% of that meal did not change gastrointestinal transit time - indicating that the inclusion of 10% seaweed meal in tilapia diet is safe and without any nutritional use losses

Desenvolvimento larval de Acetes americanus Ortmann, 1893 (Crustacea, Decapoda, Sergestidae)das baías de Paranaguá e Laranjeiras (PR)

Orientador: Chossi SinqueDissertaçao (mestrado) -Universidade Federal do Paraná. Curso de Pós-Graduaçao em ZoologiaBibliografia: f. 100-10

Testes de Toxicidade, congelamento e refrigeração em sêmen de espécie nativa

In the first part of this study, toxicity tests were performed on the sperm of Macrobrachiumacanthurus using four cryoprotectants for periods of 10 and 20 min at concentrations of 10 and 20%.In the second part, cryopreservation was performed by applying the least toxic cryoprotectant, andtwo freezing methods were tested over 24 hours: automated (protocols A and B) and conventional(protocols C and D). Protocol A exhibited a cooling rate of 0.5°C min-1 from -6°C to -32°C; protocolB was similar to A except for the starting temperature, which was room temperature; whereasprotocols C and D exhibited a cooling rate of 2 and 10°C min-1, respectively. The third part ofthe study was conducted to assess the lifespan of the sperm when stored at 5°C, in which spermviability was evaluated by a semen smear with eosin-nigrosin. The least toxic cryoprotectants were10 and 20% glycerol, and 10% methanol, and the equilibrium time was 10 minutes. The optimalcooling rate was 2°C min-1 for 10% glycerol, which had a sperm survival rate of 21.8%. Cold storagefor up to 3 days is recommended, presenting a sperm survival rate of 35.3%.Key words: caridea; cryopreservation; cryoprotectants; glycerol; methanol; shrimpA primeira estapa deste trabalho testou a toxicidade de quatro crioprotetores em espermatozoides de Macrobrachium acanthurus durante 10 e 20 min nas concentrações de 10 e 20%. A segunda etapa foi realizar a criopreservação aplicando o crioprotetor com menor grau de toxicidade, testanto dois mecanismos de congelamento, um automatizado (protocolos A e B) e outro convencional (protocolos C e D), durante 24 horas. O protocolo A apresentou velocidade de resfriamento de 0,5°C min-1 até alcançar -32°C, partindo de uma temperatura de -6°C e idem o protocolo B, com a diferença de partir de uma temperatura ambiente; os protocolos C e D apresentaram uma velocidade de resfriamento de 2 e 10°C min-1, respectivamente, sendo as palhetas transferidas ao nitrogênio líquido. A terceira etapa foi verificar o tempo de vida do espermatozoide quando refrigerado a 5°C. A viabilidade espermática foi avaliada por meio do esfregaço de sêmen com eosina-nigrosina. Os crioprotetores que se apresentaram menos tóxicos foram o glicerol 10 e 20% emetanol 10%, num tempo de equilíbrio de 10 minutos. A melhor velocidade de congelamento foi a de 2°C min-1 para glicerol 10%, com 21,8% de sobrevivência espermática, sendo a refrigeração até três dias recomendada, com uma sobrevivência de 35,3%.Fil: Costa, Tiago Viana. Universidade Federal do Amazonas; BrasilFil: Oshiro, Lidia Miyako Yoshii. Universidade Federal Rural do Rio de Janeiro; BrasilFil: Mattos, Luciana Antunes. Universidade Federal Rural do Rio de Janeiro; BrasilFil: Lopez, Laura Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Melo, Emanuela Paula. Universidade Federal Rural do Rio de Janeiro; BrasilFil: Flor, Helaine dos Reis. Universidade Federal Rural do Rio de Janeiro; Brasi

Determination of adequate voltage and animal size for the extraction of spermatophores in the freshwater prawn Macrobrachium acanthurus Determinación del voltaje y el tamaño del animal óptimos para la extracción de espermatóforos en el camarón de agua dulce Macrobrachium acanthurus

So far Macrobrachium acanthurus reproduction studies are poorly advanced being important if there is the possibility of cultivation. The aim of this study was to identify the most suitable voltage for the extraction of spermatophores and the smaller size at which these prawns produce them, as a prior step to develop in vitro fertilization techniques. Voltages of 4.5 and 6.0 were used, performing sperm count based on survival of sperm smears, colored with eosin-nigrosine. In the study of size, prawns were separated into class intervals and analyzed for production of spermatophore and sperm survival. The best voltage for the extraction of seminal material due to lower mortality was 6.0 volts and from 5 g of body weight, and 18 mm of length prawns could be used for the extraction of spermatophores.Fil: Viana da Costa, Tiago. Universidade Federal Do Amazonas; BrasilFil: Yoshii Oshiro, Lidia Miyako. Universidade Federal do Rio de Janeiro; BrasilFil: Lopez, Laura Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Melo, Emanuela Paula. Universidade Federal do Rio de Janeiro; BrasilFil: Antunes de Mattos, Luciana. Universidade Federal do Rio de Janeiro; BrasilFil: Bambozzi Fernandes, Andrea. Universidade Federal do Rio de Janeiro; Brasi