Dietary DHA and ARA level and ratio affect the occurrence of skeletal anomalies in pikeperch larvae (Sander lucioperca) through a regulation of immunity and stress related gene expression

Abstract

Several causative factors have been proposed for the occurrence of skeletal anomalies in fish larvae, among which we quote nutritional factors, such as LC-PUFAs. This study aimed to investigate the effect of different dietary DHA and ARA level and ratio on pikeperch (Sander lucioperca) larval development and performance, digestive capacity, fatty acids composition, skeleton anomalies and molecular markers of oxidative stress status (sod, gpx, and cat), stress response (StAR, gr, pparα, hsl and pepck), fatty acid synthesis (fadsd6, elovl5), eicosanoids synthesis (pla2, cox2, lox5, pge2, and lta4h), and bone development (twist, mef2c, sox9, and alp). Pikeperch larvae were fed six microdiets containing two different dietary levels of DHA (0.5% and 3.5%) combined with three levels of ARA (1.2%, 0.6%, and 0.3%). Dietary fatty acid changes did not affect growth performance but significantly influenced enzymatic activities. A significant increase in skeletal anomalies with DHA intake increment was recorded. StAR, cox2, pla2 and hsl expression were significantly depressed in 2.5% DHA larvae. An opposite effect of dietary DHA elevation was recorded in gpx expression. Both DHA and ARA had a significant effect on pparα, gr, and pge2 expressions. Although no significant interactions were found, pge2, gr, and pparα displayed a differential pattern of expression between the different treatments. A strong association was found for the larval tissue amount of ARA and DHA with eicosanoid metabolism, stress response and skeleton anomaly related genes. These results denoted the effects of dietary LC-PUFAs on immune/stress gene regulation and their potential implication in skeleton development.

Effects of dietary docosahexaenoic acid enrichment in Artemia feed on the growth, survival, and fatty acid composition of Pacific cod ( Gadus macrocephalus ) larvae

“…In the present study, despite the increase in EPA content in the experimental diets, the EPA content in larvae was not significantly altered by these diets; thus, EPA metabolism seems to be favoured over ARA metabolism in Pacific cod larvae. A negative correlation between the EPA and ARA in tissues has been reported in other studies, which suggests that they compete for inclusion in the tissues (Alves Martins et al, 2012;El Kertaoui et al, 2021;Izquierdo, 2005;Van Anholt et al, 2004). However, further studies on the effects of DHA, EPA, and ARA concentrations in live feed on the nutritional metabolomics of G. macrocephalus larvae are required.…”

Exploring Omega-3′s Impact on the Expression of Bone-Related Genes in Meagre (Argyrosomus regius)

“…Previous studies have indicated that the onset of skeletal disorders is multifactorial, linked to alterations in biotic and abiotic factors that can regulate the systemic and local factors controlling bone metabolism [1,[71][72][73][74]. Among the nutrients that can control skeletal development, dietary highly polyunsaturated fatty acids seem to play a crucial role in skeletal metabolism and bone composition in fishes [20,73,[75][76][77]. Although fatty acids have been one of the most studied nutrients, their effects on bone metabolism have not been well identified [78].…”

“…However, different studies have indicated that the consumption of moderate levels of Omega-3 promotes correct skeletal development [79]. Consequently, it is considered that the consumption of these nutrients in adequate amounts can improve bone formation and health [79], while imbalances in dietary levels have been related to several bone disorders and types of skeletal malformations [20,80]. However, the molecular mechanism involved in this beneficial effect remains mostly unknown.…”

“…Still, excessive levels seem to increase oxidative stress, ultimately affecting bone health [19]. Regarding ARA, the current literature denotes that high levels negatively affect skeletal development because it can increase bone resorption and reduce bone formation [20,21]. These effects can be related to the ability to increase the production of pro-inflammatory cytokines or ROS [22].…”

COMPARISON OF NUTRITIONAL AND PROTEASE ACTIVITY PROFILES OF TWO LIVE FEED CANDIDATES OF Pseudodiaptomus SPECIES

“…Thus, ARA plays an important role in supporting the pigmentation process and eye migration, as well as the growth and survival of either tropical and also cold water fish larvae (Mejri et al, 2021). Moreover, the content of ARA and DHA in larval tissue is closely related to eicosanoid metabolism, response to stress, and genes related to skeleton development (El Kertaoui et al, 2021), although to achieve those, it was necessary DHA, EPA, and ARA in the correct ratio (Boglino et al, 2014;El Kertaoui et al, 2021). Even though these three essential FAs are not required at high levels by marine fish larvae, the FAs are essentially present in a live feed to support the metamorphosis and growth of fish lar vae.…”