Ovopel and Carp Pituitary Extract as Spawning Inducers in Males of the Amazon Catfish Leiarius marmoratus (Gill, 1970)

The objective of this study was to evaluate Ovopel and carp pituitary extract as spawning inducers in the males of the Amazon catfish L. marmoratus. The following treatments, applied in a single dose, were studied: 0.2, 0.4 and 0.6 Ovopel pellet/kg live weight, and 2.5 mg carp pituitary extract/kg live weight. Each treatment was repeated four times. No significant difference in sperm volume, motility and vigor, time of motility, sperm count, or percentage of normal and abnormal spermatozoa was observed between the treatments. There was also no significant difference in terms of primary or secondary sperm defects, except for the secondary defect of loose heads, which was less frequent in the treatments using 0.4 and 0.6 Ovopel pellet/kg live weight. It was concluded that Ovopel could replace carp pituitary extract for induction spawning in the males of the Amazon catfish L. marmoratus.

Induced spawning and reproductive variables of the catfish Lophiosilurus alexandri Steindachner, 1876 (siluriformes: pseudopimelodidae)

Lophiosilurus alexandri is an endemic fish from the São Francisco River basin, Brazil. The aim of this study was to induce L. alexandri to spawn and to obtain data on several reproductive variables for this species. For induced spawning, adults were submitted to Cyprinus carpio pituitary homogenate (CPH). Nine of the 12 females (75%) responded positively to the treatment. The stripping of oocytes was performed 8.4 h after the second dose of CPH with the water temperature maintained at 26ºC. The number of stripped oocytes per gram of ova was 74 ± 5 oocytes g-1, and the mean oocyte diameter was 3.1 ± 0.2 and 3.6 ± 0.2 mm, before and after hydration, respectively. The oocytes were opaque, yellowish, demersal, highly adhesive, and covered by a gelatinous coat. The total fecundity was 4,534 ± 671 oocytes, and the fertilization rate was 59%. The initial and final fertilities were 2,631 ± 740 and 1,542 ± 416 embryos, respectively. Larval hatching occurred up to 56 h after fertilization, and the larvae had a total length of 8.4 ± 0.1 mm. This work provides important biological information for L. alexandri that can be used for management and conservation of this species.

Lophiosilurus alexandri é um peixe endêmico da bacia do rio São Francisco, Brasil. O objetivo do trabalho foi induzir L. alexandri à desova e obter dados sobre várias variáveis reprodutivas para esta espécie. Para desova induzida, adultos foram submetidos ao homogeneizado de hipófise de Cyprinus carpio (HHC). Nove das 12 fêmeas (75%) responderam positivamente ao tratamento. A extrusão dos ovócitos aconteceu 8,4 h após a segunda dose de HHC com a temperatura da água mantida a 26ºC. O número de ovócitos liberados por grama de ova foi de 74 ± 5 ovócitos g-1 e a média do diâmetro ovocitário foi de 3,1 ± 0,2 e 3,6 ± 0,2 mm, antes e depois da hidratação, respectivamente. Os ovócitos foram opacos, amarelo-castanho, demersais, altamente adesivos e revestidos por capa gelatinosa. A fecundidade total apresentou 4.534 ± 671 ovócitos e a taxa de fertilização foi de 59%. As fertilidades inicial e final foram de 2.631 ± 740 e 1.542 ± 416 embriões, respectivamente. A eclosão das larvas aconteceu até 56 h após a fertilização e as larvas tiveram comprimento total de 8,4 ± 0,1 mm. Este trabalho fornece informações biológicas importantes para L. alexandri, que podem ser utilizadas para o manejo e conservação desta espécie.

Induced reproduction and reproductive characteristics of Rhinelepis aspera Agassiz, 1829 (osteichthyes: Siluriformes, Loricariidae)

Rhinelepis aspera is the largest Loricariidae species found in the São Francisco river basin where it is now rarely caught. Brooders kept in tanks were hypophysed with crude carp pituitary extract (CCPE). Approximately 82 percent of the females responded positive to the treatment. The egg was opaque, demersal, round, yellow and adhesive. Egg stripping was done at 212 hour-degrees (= 8.2 h) after application of the second dose of CCPE (water temperature = 25-26 ºC). Hatching of the larvae occurred at 1022 hour-degrees (= 42.2 h), after fertilization of the eggs (water temperature =24-25 ºC). Fertilization rate of the eggs was 72 percent. Absolute fecundity (AF), initial fertility (IF) and final fertility (FF) in relation to the females' body weight are expressed, respectively, by the equations: AF = - 33993 + 122308 Wt (r² = 0.88), IF = - 14823 + 58619 Wt (r² = 0.71) and FF = - 6553 + 29741 (r² = 0.61).

Rhinelepis aspera é a espécie que atinge maior porte dentre os Locariidae da bacia do rio São Francisco onde é hoje raramente capturada. Reprodutores mantidos em viveiros foram hipofisados com extrato bruto de hipófise de carpa (EBHC). Aproximadamente 82 por cento das fêmeas responderam positivamente ao tratamento. Seus ovos eram opacos, demersais, arredondados, amarelados e adesivos. A extrusão dos ovos foi feita a 212 horas-graus (= 8,2 h) após a aplicação da segunda dose de EBHC (temperatura da água = 25-26 ºC). A eclosão das larvas ocorreu a 1022 horas-graus (= 42,2 h) após a fertilização dos ovos (temperatura da água = 24-25 ºC). A taxa de fertilização dos ovos foi de 72 por cento. Fecundidade absoluta (AF), fertilidade inicial (IF) e fertilidade final (FF) em relação ao peso corporal das fêmeas foram expressa, respectivamente, pelas equações: AF = - 33993 + 122308 Wt (r² = 0,88), IF = - 14823 + 58619 Wt (r² = 0,71) e FF = - 6553 + 29741 (r² = 0.61).