Rearing conditions and life history influence the progress of gametogenesis and reproduction performances in pikeperch males and females

Abstract

Pikeperch (Sander lucioperca) is a highly valuable fish in Europe. However, development of aquaculture of pikeperch is highly limited due to seasonality of production. This can be overcome by the controlled reproduction of domesticated fish. The first steps of domestication process may induce changes at anatomical, physiological and molecular levels, thereby affecting a variety of biological functions. While there is abundant literature on their effects on stress and growth for example, these effects on reproduction received limited attention notably in pikeperch, a promising candidate for the development of aquaculture. To answer the question of this life-history effect on pikeperch's reproduction, we compared two groups (weight: 1 kg) originated from Czech Republic and with the same domestication level (F0). The first group was a recirculating aquatic system cultured one (2 years, previously fed with artificial diet, never exposed to natural changes in temperature/photoperiod conditions) and the second one was a pond cultured group (3 to 4 years, bred under natural feeding and temperature/photoperiod). The wild group successfully spawned, while the farmed one did not spawn at all. During the program, gonadosomatic indexes of both males and females were significantly higher for the wild fish, as well as the sexual steroids. Gene expression analysis revealed significantly lower LH transcript levels at the pituitary level for the farmed females and lower FSH transcript levels at the pituitary level for the males. In conclusion this study showed that the previous rearing conditions (e.g. culture system, age, diet, etc.) alter the further progress of gametogenesis and the reproductive performances in response to controlled photothermal program for both sexes in pikeperch.

How domestication alters fish phenotypes

“…Other recent studies did not find clear differences in the reproductive features between wild and domesticated fish. Gonadogenesis in the Eurasian perch and pikeperch (Sander lucioperca), was more precocious in populations that were more domesticated (Khendek et al 2017(Khendek et al , 2018 De Almeida et al 2019), but reproductive performance was generally better for the wild fish (K ri s tan et al 2012; Khendek et al 2017). As another example, reproductive parameters and the biological quality of eggs in a farmed population were compared with those of the original wild population in brown trout (Salmo trutta).…”

“…For example, the exposure of embryos to early stressful situations can lead to further alteration of juvenile physiology (Cadiz et al 2018). A comparison of populations with different histories before an experiment led to specific responses to experimental treatments of reproductive control (Khendek et al 2018) but also of growth and behaviour (Jonsson & Jonsson 2014). Attention in all cases should be paid to the description of these life paths in order to determine whether the effects of domestication are due to adaptation to rearing conditions or to previous life events.…”

Domestication modulates the expression of genes involved in neurogenesis in high‐quality eggs of Sander lucioperca

“…Studies have revealed that besides the positive effect of domestication (evident in increased growth rate and disease and stress resistance; Douxfils et al, 2011; Teletchea & Fontaine, 2014), there are a number of processes that are negatively affected. This includes functionality of the endocrine system (Khendek et al, 2017, 2018) and gamete quality (Křišťan, Stejskal, & Policar, 2012; Lanes, Bizuayehu, de Oliveira Fernandes, Kiron, & Babiak, 2013), which leads to lowered spawning effectiveness and consequently limited production of high‐quality progeny and subsequent generations (Migaud et al, 2013; Schaerlinger & Żarski, 2015). The intensification of negative consequences are more apparent whenever the entire life cycle of the fish is closed indoor in intensive production systems (such as recirculating aquaculture systems; RAS).…”

A novel approach for induced out-of-season spawning of Eurasian perch, Perca fluviatilis

“…During the domestication process, fish, together with the adaptation to the culture environment, deviated in terms of gonadal development and physiological responses to photothermal manipulations (Khendek et al, 2018(Khendek et al, , 2017. This phenomenon puts in question the effectiveness of the potential transfer of reproductive protocols developed based on wild (or wild-like, similar to the protocols used in this study) fish to the domesticated stocks.…”

“…However, reproductive protocols were mainly developed with the use of wild or pond-reared fish (which is considered a wild-like fish due to its exposure to natural photothermal fluctuations and its foraging on live prey; Żarski et al, 2015) because of very limited access to domesticated breeders. The transfer of knowledge from wild to domesticated fish is often questioned due to the physiological differences reported between the two types of broodstock (Khendek et al, 2017(Khendek et al, , 2018. To date, there have been no attempts to transfer the protocols developed for wild percids to domesticated stocks.…”