Spawning kinetics and egg/larval quality of greater amberjack (Seriola dumerili) in response to multiple GnRHa injections or implants.
Gen Comp Endocrinol
; 279: 78-87, 2019 08 01.
Article
en En
| MEDLINE
| ID: mdl-30571964
ABSTRACT
The greater amberjack (Seriola dumerili) is one of the most promising finfish species for aquaculture, due to its cosmopolitan distribution and acceptability, high growth rates and large size. However, lack of reproduction control has been one of the main bottlenecks for its commercialization. The study examined two endocrine methods for the induction of oocyte maturation/ovulation and spawning, which are based on the induction of endogenous Luteinizing Hormone (LH) release from the pituitary, through the use of Gonadotropin Releasing Hormone agonist (GnRHa) either in the form of sustained-release delivery systems (implants) or injections (acute release). The stock (nâ¯=â¯28) consisted of wild fish captured in 2011 and each GnRHa administration method was conducted in two replicates, with 6 and 8 fish per tank, respectively, at a 11 sex ratio. Fish were given a GnRHa injection once a week (three administrations), or a GnRHa implant every 2â¯weeks (two administrations). Mean daily relative fecundity was significantly higher (t1.3â¯=â¯-5.24, Pâ¯=â¯0.012) in the implanted fish (15,170⯱â¯2,738â¯eggsâ¯kg-1 female day-1) compared to the injected fish (6,119⯱â¯2,790â¯eggsâ¯kg-1 female day-1). Total relative fecundity was also significantly higher (t1.3â¯=â¯-9.93, Pâ¯=â¯0.003) in the implanted fish (102,402⯱â¯20,337â¯eggsâ¯kg-1 female) compared to the injected ones (26,517⯱â¯9,938â¯eggsâ¯kg-1 female), but there were no differences in the quality of eggs in terms of fertilization, 24-h embryo survival, hatching and 5-d larval survival. The number of females with fully vitellogenic oocytes eligible for induction of spawning decreased from the initial to the final sampling, from 7 to 6 females for the GnRHa implant treatment and from 7 to 3 females for the GnRHa injection treatment. In addition to apparently promoting the proper endocrine changes leading to multiple cycles of oocyte maturation, ovulation and spawning, and thus producing larger numbers of eggs; the use of GnRHa implants may be more appropriate in greater amberjack than multiple injections because (a) it also stimulates vitellogenesis and (b) involves less handling of the fish.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Óvulo
/
Reproducción
/
Perciformes
/
Hormona Liberadora de Gonadotropina
/
Implantes Experimentales
Límite:
Animals
Idioma:
En
Revista:
Gen Comp Endocrinol
Año:
2019
Tipo del documento:
Article
País de afiliación:
Grecia