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Temporal dynamics of oocyte development, plasma sex steroids and somatic energy reserves during seasonal ovarian maturation in captive Murray cod Maccullochella peelii peellii

journal contribution
posted on 2007-12-01, 00:00 authored by Dane Newman, Paul Jones, Brett Ingram
The temporal dynamics of oocyte growth, plasma sex steroids and somatic energy stores were examined during a 12 month ovarian maturation cycle in captive Murray cod Maccullochella peelii peelii under simulated natural photothermal conditions. Ovarian function was found to be relatively uninhibited in captivity, with the exception that post-vitellogenic follicles failed to undergo final maturation, resulting in widespread pre-ovulatory atresia. Seasonal patterns of oocyte growth were characterised by cortical alveoli accumulation in March, deposition of lipids in April, and vitellogenesis between May and September. Two distinct batches of vitellogenic oocytes were found in Murray cod ovaries, indicating a capacity for multiple spawns. Plasma profiles of 17β-oestradiol and testosterone were both highly variable during the maturation period suggesting that multiple roles exist for these steroids during different stages of oocyte growth. Condition factor, liver size and visceral fat stores were all found to increase prior to, or during the peak phase of vitellogenic growth. Murray cod appear to strategically utilise episodes of high feeding activity to accrue energy reserves early in the reproductive cycle prior to its deployment during periods of rapid ovarian growth.

History

Journal

Comparative biochemistry and physiology. Part A, Molecular & integrative physiology

Volume

148

Issue

4

Pagination

876 - 887

Publisher

Elsevier Inc

Location

Amsterdam, Netherlands

ISSN

1095-6433

eISSN

1531-4332

Language

eng

Notes

Available online 11 September 2007.

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2007, Elsevier Inc.