Fish Oocyte Ageing and its Effect on Egg Quality

Abstract

In fish, delayed spawning in nature, delayed egg collection in capture and delayed fertilization after egg stripping can lead to oocyte ageing and over-ripening. Oocyte ageing is reported as one of the most important factors affecting the egg quality. During over-ripening, morphological, physiological, biochemical, histological, cellular, and molecular changes occur inside the eggs and ovarian fluid. These alterations can negatively affect the egg fertilization capacity and successive developmental stages. The time period during which eggs remain viable after ovulation or stripping has been reported from a few minutes to a few weeks depending on the fish species and the storage temperature. Although several biomarkers that characterize the over-ripening phenomenon have been defined, the reliability of these parameters in the field of aquaculture is controversial. For future researches, inhibition of oocyte ageing by antioxidants could be a valuable research topic. In the present article, the morphological, physiological, biochemical, histological, cellular, and molecular changes that occur during oocyte over-ripening under in vivo conditions and during in vitro storage are reviewed and possible reasons for the decrease in viability of eggs are presented. Species-specific changes in the egg viability and larval development are also considered.

Investigating fish migration, mortality, and physiology to improve conservation planning of anadromous salmonids: a case study on the endangered North Sea houting (Coregonus oxyrinchus)

“…Reduced upstream migration speeds through the artificial lakes could eventually delay spawning activities further upstream. Previous studies have reported that forced delays of spawning often reduce egg survival because of excessive egg ageing after ovulation (Gaudemar and Beall 1998;Samarin et al 2015). It is well known that migratory delays can have severe negative consequences (Svendsen et al 2011;Crozier et al 2017;Schwinn et al 2018); however, we found no correlation between the times spent traversing the artificial lakes and subsequent arrival dates in the spawning areas, suggesting that the reduced migration speeds through the lakes did not translate into delayed spawning.…”

The substrate selection and spawning behaviour of pikeperch Sander lucioperca L. broodstock under pond conditions

“…The pikeperch Sander lucioperca is a promising fish species for aquaculture production because of its flesh quality and high market value (Blecha, Kristan, Samarin, Rodina, & Policar, 2015;Samarin, Policar, & Lahnsteiner, 2015). Over the past 10 years, pikeperch production in Europe has increased (FAO, 2018;Steenfeldt et al, 2015).…”

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

“…In ovulating teleosts, the mature eggs are released into the ovarian lumen, or into the abdominal cavity in salmonids (Bobe & Labbe, 2010), and remain there until spawning. If the eggs are retained, they will lose their ability to be fertilized; i.e., they over ripen (Lam et al, 1978;McEvov, 1984;Rime et al, 2004;Samarin et al, 2015). The time that this takes depends on species and temperature (Bromage et al, 1992(Bromage et al, , 1994Gillet, 1991;Springate et al, 1984).…”

“…If spawning or spontaneous release (G. aculeatus females may drop their eggs in the absence of males) of the ovulated eggs does not happen, the eggs will become overripe, i.e. they will not be viable, they harden and cannot even be laid as the female becomes egg-bound (Samarin et al, 2015). Overripe ovulated eggs are not to be confused with non-ovulated oocytes that become atretic.…”