24 research outputs found

    Feed transition in larval rearing of bocudo, Steindachneridion scripta (Pisces, Pimelodidae), using Artemia spp. nauplii and artificial diet Transição alimentar na larvicultura do bocudo, Steindachneridion scripta (Pisces, Pimelodidae), com o uso de náuplios de Artemia spp. e dieta artificial

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    Feed transition of Steindachneridion scripta larvae was investigated using seven treatments in which the reference diet, Artemia spp. nauplii, was totally substituted for a 56% crude protein artificial diet in two-day intervals. Initially, all treatments were fed with Artemia spp. nauplii and, subsequently, during the transition period, feed was equally composed by Artemia sp. nauplii and artificial diet. Everyday, one of the treatments began the feed transition, which was implemented between the second and the eighth days of culturing. Two treatments were used as control: one exclusively fed Artemia spp. nauplii and another only with artificial diet. Total weight, total length, and survival rate were not influenced by the day in which feed transition was implemented (P>0.05), and their mean values (± SD) were 31.1&plusmn;25.0mg, 13.3&plusmn;1.5mm and 58.8&plusmn;12.0%, respectively. This suggests that Steindachneridion scripta larvae adapted well the transition to artificial diet.<br>A transição alimentar de larvas de Steindachneridion scripta foi investigada utilizando-se sete tratamentos, nos quais a dieta básica, composta por náuplios de Artemia spp., foi integralmente substituída, em intervalo de dois dias, por uma dieta artificial contendo 56% de proteína bruta. Inicialmente, todos os tratamentos receberam náuplios de Artemia spp. No período de transição alimentar, metade da alimentação foi formada por náuplios de Artemia spp. e metade por dieta artificial. A cada dia, um dos tratamentos entrou na fase de transição, que foi implementada entre o segundo e o oitavo dia de cultivo. Utilizaram-se dois tratamentos como controle; em um as larvas foram alimentadas, exclusivamente, com náuplios de Artemia spp. e em outro, somente, com dieta artificial. Peso total, comprimento total e sobrevivência não foram influenciados pelo dia de implantação da transição alimentar (P>0,05) e, apresentaram valores médios iguais a (&plusmn; desvio padrão) 31,1&plusmn;25,0mg, 13,3&plusmn;1,5mm e 58,8&plusmn;12,0%, respectivamente, sugerindo que as larvas Steindachneridion scripta aceitaram bem a transição alimentar para a dieta artificial

    Survival and growth of Pseudoplatystoma corruscans (Pisces - Pimelodidae) larvae: effect of photoperiod Sobrevivência e crescimento de larvas de surubim, Pseudoplatystoma corruscans (Pisces, Pimelodidae): efeito do fotoperíodo

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    The survival and the growth of Pseudoplatystoma corruscans larvae exposed to four photoperiods: light:dark (LD) 0:24, LD 10:14, LD 14:10, and LD 24:0, in a brackish water (5&#8240;) culture were analyzed. Larvae were fed with Artemia sp. nauplii at a 500 nauplii/larvae/day ratio. Survival on day 5 was inversely related to the length of photoperiod. From days 5 to 10, intermediate photoperiods resulted in a better survival, although LD 0:24 and LD 14:10 resulted in similar survival on day 10. Larvae presented higher weight at intermediate photoperiods. The results suggested that photoperiod requirements shifted during early development of P. corruscans larvae.<br>A sobrevivência e o crescimento de larvas de surubim, Pseudoplatystoma corruscans, submetidas a quatro fotoperíodos: luz:escuro (LE) 0:24, LE 10:14, LE 14:10 e LE 24:0 em água salinizada (5&#8240;) foram avaliadas. As larvas foram alimentadas com náuplios de Artemia sp. na proporção de 500 náuplios/larva/dia. Após cinco dias de experimento, a sobrevivência apresentou relação inversa ao aumento do fotoperíodo. Entre o quinto e o 10º dia, houve tendência de maior sobrevivência nos fotoperíodos intermediários, mas foram registradas sobrevivências semelhantes no intervalo entre LE 0:24 e LE 14:10 no 10º dia. As larvas apresentaram maior peso nos fotoperíodos intermediários. Os resultados sugerem que a exigência de fotoperíodo das larvas de P. corruscans sofre mudanças durante o cultivo

    Inferring phylogenetic trees using answer set programming

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    We describe the reconstruction of a phylogeny for a set of taxa, with a character-based cladistics approach, in a declarative knowledge representation formalism, and show how to use computational methods of answer set programming to generate conjectures about the evolution of the given taxa. We have applied this computational method in two domains: to historical analysis of languages, and to historical analysis of parasite-host systems. In particular, using this method, we have computed some plausible phylogenies for Chinese dialects, for Indo-European language groups, and for Alcataenia species. Some of these plausible phylogenies are different from the ones computed by other software. Using this method, we can easily describe domain specific information (e.g., temporal and geographical constraints), and thus prevent the reconstruction of some phylogenies that are not plausible
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