Continuous lighting inhibits the onset of reproductive cycle in pikeperch males and females

Abstract

The effect of a constant photoperiod on the inhibition of male and female reproductive cycles was studied in pikeperch Sander lucioperca. Over a 153-day period, batches of pikeperch (2 years, 950 g) breeders were kept under either under natural or artificial photoperiod conditions (24L:0D) (30-35 fish/tank, triplicate) and sampled in late June (start of the photoperiod decrease in natural conditions), late August (start of temperature decrease) and late November (exogenous vitellogenesis) (7-10 fish/tank/sampling date). Morphological parameters, sexual steroids, alkaline-labile phosphate (µg/mL) levels and gamete developmental stages were investigated. Gonado-somatic index (%), developmental stages and sexual steroid levels (17β-estradiol, testosterone and 11-ketotestosterone, ng/mL) in both sexes and oocyte diameter (µm) and plasma alkaline-labile phosphate (µg/mL) in females were lower in response to a continuous lighting (24L:0D). In both sexes, continuous lighting applied in June for 153 days totally inhibited or delayed the onset of the reproductive cycle. In conclusion, photoperiod manipulation can be used to delay the pikeperch reproductive cycle, even if temperature decreases. This is the first report of the inhibitory effect of photoperiod on the onset of the reproductive cycle in pikeperch.

Seasonal simulated photoperiods influence melatonin release and immune markers of pike perch Sander lucioperca

“…The decrease in day length is involved in the initiation of gametogenesis in many fish species including the walleye (Sander vitreus) 55 and the Eurasian perch 56 . Our results are also consistent with results from Ben Ammar et al 57 showing that the initiation of gonadogenesis seems to be mainly driven by photoperiodic changes. However, both temperature and photoperiod variations must be considered in the control of pikeperch reproductive cycle 57,58 .…”

“…Our results are also consistent with results from Ben Ammar et al 57 showing that the initiation of gonadogenesis seems to be mainly driven by photoperiodic changes. However, both temperature and photoperiod variations must be considered in the control of pikeperch reproductive cycle 57,58 .…”

Influence of waterborne gallic and pelargonic acid exposures on biochemical and reproductive parameters in the zebrafish (Danio rerio)

“…Midpart of two males and two females per exposure tank ( n total = 12 specimens per treatment) were fixed in Bouin–Holland solution for 1 week, washed once with water, twice with 70% ethanol, and stored in absolute ethanol (Abdulfatah et al, ). Fragments of 5 mm thick slices were cut from each individual, dehydrated in OTTIX solution and embedded in the Diawax paraffin substitute (adapted from Langeron, and Ben Ammar et al, ). For females, sections of 6 µm were cut from the Diawax block and stained with a trichrome: hematoxylin Gill III, 0.5% phloxine B, and 0.5% light green (Rinchard and Kestemont, ).…”

“…The number of oocytes at each developmental stage was counted using an optical microscope (Nikon Eclipse Ni‐U) equipped with a DS‐Fi2 digital camera associated to the software NIS BR (Nikon France, Champigny‐sur‐Marne, France), and expressed as relative percentage of total follicle number in the whole section examined. For male gonad examination, sections of 4 µm of fixed midpart of specimens in Diawax blocks were cut and also stained with a trichrome (Ben Ammar et al, ): Regaud's iron haematoxylin, 1% Ponceau‐Fushine of Masson, and 0.1% light green. Testes cells were classified according to three general sperm germ cell categories (Fig.…”

Constant long photoperiod inhibits the onset of the reproductive cycle in roach females and males

“…Samples of both ovaries and testis were stored in a Bouin-Holland solution for one week, washed once with water, twice with 70% ethanol and stored in absolute ethanol (Ben Ammar et al, 2015). Then, fragments of gonads were cut into 5 mm thick slices, dehydrated with OTTIX solution (DIAPATH SpA, Italy/ MM France), and embedded in a paraffin substitute dubbed Diawax (DIAPATH SpA, Italy / MM France) (adapted from Langeron, 1913).…”