Seletividade alimentar de organismos-alimento por formas jovens de pacu <em>Piaractus mesopotamicus</em> (Holmberg, 1887) e curimba <em>Prochilodus lineatus</em> (Valenciennes, 1836)

Abstract

Objetivou-se avaliar a seleção alimentar de organismos-alimento por formas jovens de pacu (Piaractus mesopotamicus) e curimba (Prochilodus lineatus) com diferentes idades (6, 12, 19 e 26 dias), na presença e ausência de Pistia stratiotes. Foram utilizados quatro tratamentos (T1 = pacu + P. stratiotes; T2 = pacu; T3 = curimba + P. stratiotes; T4 = curimba) e quatro repetições. A cada sete dias, foram coletadas 24 larvas de cada espécie de peixe dos tanques, sendo estas mantidas em jejum por 24 horas. Depois de distribuídas nos aquários com plâncton, as larvas permaneceram por três horas, sendo coletadas e fixadas para análise, juntamente com as amostras de água. Os tratos digestórios das larvas foram retirados e analisados sob microscópio óptico. Observaram-se diferenças estatísticas na seletividade alimentar de organismos planctônicos por larvas de mesma espécie, em diferentes idades e também entre larvas de espécies diferentes, com mesma idade, não diferindo quanto à presença ou ausência de P. stratiotes. As formas jovens de pacu e curimba selecionaram organismos similares aos seis dias de idade, passando por alterações até o 26º dia. À medida que se desenvolveram, as larvas de pacu passaram a selecionar cladóceros e ostrácodos e as de curimba, protozoários e algas.

<b>Influence of <i>Eichhornia crassipes</i> and Lemna sp. on the natural diet of <i>Astyanax altiparanae</i> Garutti & Britski, 2000 in the initial stages

“…Meantime, these larvae started to consume larger organisms, such as Chironomidae immature, in the last two age classes in this treatment, as also observed in tanks with E. crassipes, from 15 to 39 days of age. These results confirm those presented by Marques, Hayashi, Galdioli, & Fernandes (2007), where the cladoceran Macrothrix sp. was the dominant item in the diet of P. mesopotamicus in the early developmental stages from 6 to 33 days of age and P. lineatus, from 6 to 15 days, in tanks with or without P. stratiotes.…”

“…In tanks containing Lemna sp., rotifers and algae were the most frequent in the second, third and fourth age classes, and cladocerans showed a higher frequency in the first class. Similar results were registered by Marques et al (2007) reported that smaller organisms, such as Difflugia sp., Lecane sp. and algae, had higher frequency of occurrence in the diet of P. lineatus in tanks with macrophytes (P. stratiotes) with increasing age, as obtained in this study for A. altiparanae at early developmental stage in tanks with Lemna sp.…”

“…In some studies, such as Furuya et al (2002) on Pseudoplatystoma corruscans, it has been found that smaller organisms like rotifers becomes less frequent with increasing age of the post-larvae, with an increase in the frequency of occurrence of larger organisms, such as cladocerans, copepods, ostracods and insect larvae, as also verified by Makrakis et al (2005) for larvae of Iheringichthys labrosus and Hypophthalmus edentatus, for P. mesopotamicus and P. lineatus by Marques et al (2007) and for Plectropomus leopardus by Qu et al (2012). Changes that take place with increasing age of fish larvae, in which some species prefer smaller organisms and other species, larger ones, depend on feeding habits of each species Acta Scientiarum.…”

Natural food intake by juvenileArapaima gigasduring the grow-out phase in earthen ponds

“…The zooplankton was analysed qualitatively and quantitatively in triplicate samples of 1 ml in a Sedwick-Rafter chamber (Marques, Hayashi, Galdioli & Fernandes, 2007), and pond water quality parameters were analysed (pH, temperature, dissolved oxygen, transparency, total ammonia, alkalinity and hardness). Stomach content was also analysed qualitatively and quantitatively.…”

Feeding activity and influence of intraspecific competition on zooplankton communities by jundiá (Rhamdia quelen Quoy and Gaimard, 1824) in laboratory

“…Planktonic organisms occupy a well-defined position in the transfer of energy in aquatic ecosystems, since the majority of species of fish utilise them as food during the first phases of development, where changes occur with respect to items ingested as the fish grow (Sipauba-Tavares, 1993;Ribeiro et al, 2001;Hayashi et al, 2002Feiden et al, 2006Marques et al, 2007).…”