Effect of water temperature and prey concentrations on initial development of Lophiosilurus alexandri Steindachner, 1876 (Siluriformes: Pseudopimelodidae), a freshwater fish

Abstract

The aim of this study was to investigate the effects of water temperature and prey concentrations (Artemia nauplii) on the initial development of Lophiosilurus alexandri larvae. The experiment was conducted using a 4 x 2 factorial design, with four water temperatures (23, 26, 29 and 32 °C), two different initial prey concentrations (P 700 and P 1,300 ) and three replicates. Feeding was increased during the fifteen-day experiment. At the end of the experiment, the survival and condition factor were affected only by prey concentrations, with elevated numbers of Artemia nauplii leading to higher averages of these variables. The total length (TL) and specific growth rate were separately influenced by temperature and prey concentration, without interaction between them, and weight showed an interaction with these factors. In general, an increase of temperature (23 to 32 °C) improved the growth and nitrogen gain in L alexandri larvae. For TL, the optimal temperatures estimated were 31.4 and 31.0 °C for P 700 and P 1,300 , respectively. Similar mean body weight larvae and nitrogen gain were observed at 23 °C for both levels of prey concentrations. For other temperatures, the P 1,300 level provided greater weight gain for L. alexandri. Therefore, it is suggested that temperatures between 29-32 °C combined with a higher level of prey concentration maximise the development and nitrogen gain in L. alexandri larvae. Moreover, this is the first result about nitrogen incorporation in neotropical fish larvae.O objetivo deste estudo foi investigar os efeitos da temperatura da água e concentrações de presas (náuplios de Artemia) no desenvolvimento inicial de larvas de Lophiosilurus alexandri. O experimento foi conduzido em esquema fatorial 4 x 2, com quatro temperaturas da água (23, 26, 29 and 32 °C), duas concentrações de presas (P 700 e P 1.300 ) e três réplicas. A quantidade de alimento ofertado aumentou durante os 15 dias de experimento. Ao final do experimento a sobrevivência e o fator de condição foram afetados apenas pela concentração de presas, sendo que a maior concentração proporcionou médias superiores para as variáveis mencionadas. O comprimento total (CT) e a taxa de crescimento específico foram influenciados separadamente pelos fatores temperatura e concentração de presa, sem interação entre os fatores, e o peso individual das larvas apresentou interação entre os fatores estudados. Em geral, o aumento da temperatura (de 23 para 32 °C) promoveu o crescimento e o ganho em nitrogênio nas larvas de L alexandri. Para o CT, a temperatura ótima ficou em 31,4 e 31,0 °C para P 700 e P 1.300 , respectivamente. Médias semelhantes do peso individual e ganho em nitrogênio foram observadas nos animais cultivados a 23 °C em ambos os níveis de concentração de presas. Nas demais temperaturas, o nível de P 1.300 levou a um maior ganho em peso para as larvas de L. alexandri. Desta forma, conclui-se que o desenvolvimento inicial das larvas de L. alexandri é afetado por ambos os fatores estudados, e temperaturas entre 29-32 °C combinad...

Development, nutrition, and rearing practices of relevant catfish species (Siluriformes) at early stages

“…This species is considered vulnerable to extinction, 47 although it has not yet been classified by the IUCN. In this context, efforts have been made to improve the production of fingerlings for restocking programmes in the Rio São Francisco basin, 48‐51 as well as for human consumption 52,53 . No hybrids with other catfish species have been reported.…”

Description of amino acid and fatty acid content during initial development of Lophiosilurus alexandri (Siluriformes: Pseudopimelodidae), a carnivorous freshwater catfish

“…In L. alexandri, a sedentary species that occupies the bottom of rivers, this reduction in Trp levels during ontogeny may indicate that the concentration of this AA is reduced dramatically before the first feeding. One has to also consider that this species exhibits cannibalistic behavior in the early stage of life, which can be stopped when a source of live food is offered (Santos, Luz, 2009;Takata et al, 2014).…”

“…Pacamã, Lophiosilurus alexandri (Siluriformes: Pseudopimelodidae) (Steindachner, 1876), is a carnivorous freshwater fish that reproduces naturally in captivity (Costa et al, 2015). The use of Artemia during the larviculture has provided survival values around 96.9% (Takata et al, 2014). After the process of feeding training, juveniles respond positively to the exclusive consumption of pelleted feed (Cordeiro et al, 2016), a factor that is favorable for the potential captive production of the species.…”

Feed management and stocking density for larviculture of the Amazon ornamental fish L333 king tiger pleco Hypancistrus sp. (Siluriformes: Loricariidae)

“…Newly hatched Artemia spp. nauplii obtain satisfactory results when given from the first feeding, promoting larval growth and development (Jomori et al., 2008; Leitão et al, 2011; Luz et al., 2011; Takata et al, 2014). This has been observed for the Amazon ornamental fish species Nannostomus beckfordi (Abe et al., 2019), Pyrrhulina brevis (Abe et al., 2016), Heros severus (Abe et al., 2018), Astronotus ocellatus (Jomori et al., 2013) and others, such as pacu Piaractus mesopotamicus (Jomori et al., 2012; Leitão et al., 2011; Portella et al., 2014), Rhinelepis aspera (Santos et al., 2012), Lophiosilurus alexandri (Santos et al., 2016), tambaqui Colossoma macropomum , matrinxã Brycon amazonicus (Barros et al, 2019) and piau Leporinus macrocephalus (Jomori et al., 2013).…”