Aspectos reprodutivos e perfil hormonal dos esteróides sexuais do pirarucu, Arapaima gigas (SCHINZ,1822), em condições de cativeiro

Abstract

RESUMOEsta pesquisa teve como objetivo caracterizar a reprodução e o perfil hormonal dos esteróides sexuais do pirarucu, Arapaima gigas, além de validar um aspecto do dimorfismo sexual secundário. O experimento foi realizado na Fazenda Santo Antônio II, em Presidente Figueredo-AM, no período de fevereiro de 2004 a fevereiro de 2005. Foram selecionados 24 exemplares e divididos em três grupos de oito peixes (grupo "A", "B" e "C" com pirarucus de mais de quatro anos de idade, com três anos e dois anos, respectivamente). Os pirarucus foram estocados em três tanques de 400m 2 , um para cada grupo. Aspectos comportamentais, como o interesse por alimento, brigas, formação de casais e presença de ninhos, foram observados ao longo de todo o experimento. Amostras de sangue foram coletadas mensalmente, de todos os peixes, observou-se a presença de uma mancha alaranjada no macho como uma característica sexual secundária. Foram mensurados os níveis de testosterona (T), 17beta-estradiol (E 2 ) e 17alfa-hidroxi-progesterona (17aOHP) através de radioimunoensaio (RIA) de fase sólida. Todos os machos dos grupos "A" e "B" puderam ser identificados pela mancha alaranjada na região inferior da cabeça, corroborada pela concentração de testosterona, comprovando o conhecimento empírico dos ribeirinhos. Os níveis de T e E 2 nos peixes do grupo "A" e "B" tiveram maiores picos no início do período de chuva, enquanto que o 17aOHP teve oscilações constantes e pequenos picos no final do período chuvoso, os peixes do grupo "C" acompanharam essa tendência em concentrações menores. PALAVRAS-CHAVE: pirarucu, reprodução, esteróides sexuais, Arapaima gigas. Reproductive Aspects and Sexual Steroids Hormonal Profiles of Pirarucu, Arapaima gigas (SCHINZ,1822), in Captivity Conditions ABSTRACTThe purpose of this study was to characterize the growth, reproduction and hormonal profile of pirarucu, Arapaima gigas, and validate one sexual dimorphism characteristic. The experiment was carried in the fish farm Santo Antonio II, Presidente Figueredo city in the state of Amazonas -Brazil, from February 2004 to February 2005 In the experiment, 24 fishes were selected and divided in three groups, with eight fish in each one. The pirarucus from "A" group were older than four years. In "B" group the fishes were three years old and in "C" group these were two years old. The pirarucus were stocked in 400 m 2 excavated ponds, one pond for each group. Reproductive behavior like feeding interest, fights, pair formation and presence of nest were observed. Blood samples were taken monthly from all fishes during the experiment period, the sexual dimorphism characteristic was observed. Testosterone (T), 17b-estradiol (E 2 ) and 17ahidroxi-progesterona (17aOHP) levels were measured by radioimunoassay (RIA) in solid phase. All males of group "A" and "B" could be identified by an orange mark under the head, and the levels of T validated this data, proving the empirical knowledge of river men. T and E 2 levels of group "A" and "B" picked in the beginning of raining period an...

Cytogenetics, genomics and biodiversity of the South American and African Arapaimidae fish family (Teleostei, Osteoglossiformes)

“…The natural distribution of these fishes covers a large part of the Brazilian Araguaia–Tocantins and Amazon River basins [ 16 , 17 ]. They live preferentially in lentic environments such as floodplains and lakes, with significant sedentary behavior [ 18 , 19 ], displaying complex reproductive strategies, including nest building and a high level of parental care [ 20 , 21 ]. Being one of the largest freshwater fishes of the planet, with individuals measuring up to 4 m in length, they have been subjected to extensive fishery activities for years [ 6 ].…”

Pirarucu: from its origins to commercial breeding

“…Pirarucu is an ovuliparous monogamous fish (Monteiro, 2005) whose sexual maturation occurs from the 4th to the 5th year of life, when it reaches 1.60-1.85 m in length and 40-45 kg in weight (Lüling, 1964;Flores, 1980). During the dry season, the fish forms couples that last throughout their lifetime.…”

“…Despite the good results generated with projects like RDSM, which in 2011 achieved the production of 305 t of pirarucu in all areas managed by the Mamirauá Institute, which reported an increase in both production and number of fishermen registered in the period of 1999 to 2011 (production of 3 t of pirarucu in 1999 and 42 to 961 fishermen), the current availability of pirarucu per extractive fishing operation does not meet the market demand, which grows daily (Amaral et al, 2011). Therefore, in addition to the maintenance of conservation-management strategies in nature, much research has been done on the captive breeding of pirarucu, which can be a viable alternative to meet the domestic and external market demands without compromising the native population (Monteiro, 2005).…”

Caracterización histológica de folículos ováricos de Arapaima gigas (Cuvier, 1817) de 12, 18 y 24 meses de edad

“…Sin embargo, no existe información sobre el desarrollo folicular en el crecimiento, tal y como se conoce en otras especies de teleósteos (Rocha M y Rocha E, 2006). La insuficiente información disponible acerca de la biología reproductiva de la especie trae como consecuencia un manejo inadecuado de programas de reproducción según la edad del pez, dificultando la obtención de alevinos (Monteiro et al, 2010).…”