Changes in Red Color Sensitivity over the Spawning Cycle of Female Three-spined Stickleback ().

Male red nuptial coloration is a primary mating signal for three-spined sticklebacks (), and the retinae of both sexes are especially sensitive to red during the breeding season. Red sensitivity is an important aspect of female mate choice in this species, but only when they are ready to spawn and not over the entire breeding period. Here, we aimed to determine if the red sensitivity of female sticklebacks change over their repeat spawning cycle.

Ovarian fluid in the three-spined stickleback Gasterosteus aculeatus: effects of egg overripening and sex steroid treatment.

The ovarian fluid properties of the three-spined stickleback Gasterosteus aculeatus were studied in overripe and non-overripe ovulated female sticklebacks and in females that were implanted with Silastic capsules containing testosterone (T), oestradiol (E2), 17,20β-dihydroxypregn-4-en-3-one (17,20β-P) or progesterone (P4) into the abdominal cavity. Overripe females had less ovarian fluid than non-overripe females, but with higher dry mass, higher protein concentration and lower viscosity. T and 17,20β-P increased the amount of ovarian fluid and the fluid protein concentration was increased by 17,20β-P.

Hormonal changes over the spawning cycle in the female three-spined stickleback, Gasterosteus aculeatus.

Female three-spined sticklebacks are batch spawners laying eggs in a nest built by the male. We sampled female sticklebacks at different time points, when they were ready to spawn and 6, 24, 48 and 72h post-spawning (hps) with a male. Following spawning, almost all females (15 out of 19) had ovulated eggs again at Day 3 post-spawning (72hps).

Starvation and re-feeding affect Hsp expression, MAPK activation and antioxidant enzymes activity of European sea bass (Dicentrarchus labrax).

In the context of food deprivation in fish (wild and farmed), understanding of cellular responses is necessary in order to develop strategies to minimize stress caused by starvation in the aquaculture section. The present study evaluates the effects of long term starvation (1F-3S: one-month feeding-three-month starvation) and starvation/re-feeding (2S-2F: two-month starvation-two-month re-feeding) compared to the control group (4F-0S: four-month feeding-zero month starvation) on cellular stress response and antioxidant defense in organs, like the intestine, the liver, the red and white muscle of European sea bass Dicentrarchus labrax. Molecular responses were addressed through the expression of Hsp70 and Hsp90, the phosphorylation of stress-activated protein kinases and particularly p38 mitogen-activated protein kinase (p38 MAPK) and the extracellular signal-regulated kinases (ERK-1/2).

Expression of developmental-stage-specific genes in the gilthead sea bream Sparus aurata L.

The mechanism of early fish development as well as the control of egg quality is of great importance for the ability of the oocyte to develop after fertilization. Embryonic development is initially regulated by maternally provided mRNAs and later by the zygotic genome. Maternal mRNAs have an important role in initiating processes crucial to patterning the developing fish embryo.