Fatty Acid Composition of Eggs and its Relationships to Egg and Larval Viability from Domesticated Common Sole (Solea solea) Breeders

Abstract

The study of lipids and fatty acids (FAs) has been used in the assessment of egg quality because their composition can influence the fertilization rate, hatching, survival and growth of marine fish larvae. For these reasons, the lipid content (TL) and fatty acid composition of common sole (Solea solea) eggs were measured and correlated to egg and larval viability parameters throughout an entire reproductive season. Seventeen batches of fertile eggs obtained from natural spawning of captive breeders were characterized for the TL, FA profile, hatching rate (HR) and survival rate of larvae (SR) at 0-6 days post-hatching (dph). The egg FA composition reflected the composition of the feed supplied to the broodstock during summer and autumn (before and during vitellogenesis) rather than that supplied during the spawning season. In general, the egg FA profile showed minimal differences among the early-, mid- and late-spawning periods (possibly due to the change of the diet and/or water temperature) indicating that it is possible to obtain a similar egg quality in terms of egg FA profile over 2 months of spawning. Saturated FAs and monounsaturated FAs (MUFA) were positively correlated with HR, while TL, 22 : 6n-3 (DHA), 20 : 4n-6 (ARA), polyunsaturated FAs of the (n-3) series (n-3 PUFA) and polyunsaturated FAs of the (n-6) series were negatively correlated (p ≤ 0.05). MUFA, 20 : 5n-3 (EPA), n-6/n-3 were positively correlated with SR, while DHA, n-3 PUFA, DHA/EPA were negatively correlated (p ≤ 0.05). In conclusion, the feed supplied before and during vitellogenesis has a major role in determining the egg FA profile in common sole. The relationships found between TL and FAs with egg and larval viability parameters differ from many other farmed marine fish species, which may suggest the need for a specific broodstock feed for this species.

Farmed and wild common sole (Solea solea L.): Comparative assessment of morphometric parameters, processing yields, selected nutritional traits and sensory profile

“…At this regard, natural dietary regime of sole, such as Polychaeta species, is generally poor in lipid and proportionally high in EPA with only residual amount of DHA. In addition, the DHA tissue levels of the present study may be also related to the possible capability of sole species for a selective tissue retention of DHA or biosynthesis of DHA from EPA as recently highlighted in egg quality and lipid metabolism studies of sole species (Morais et al, 2016;Parma et al, 2015). Commercial aquafeed is expected to contains higher lipid and DHA level (depending on the fishmeal and fish oil dietary level) then the natural sole's diet, thus leading to a higher content in the flesh of fish under farming condition.…”

“…During the same period farmed common sole (FS, n = 220) were collected at first commercial size (20.4 ± 1.13 cm) from a farm located in south-eastern Italy (Panittica Italia, Fasano, BR). Fingerlings were produced from common sole breeders with northern Adriatic origin maintained at the Aquaculture Laboratory of the Department of Veterinary Medical Sciences at the University of Bologna according to Parma et al (2015). Fingerlings were transferred to the farm at a size of 0.5 g and then on-grown for 18 months in intensive conditions (density, 5-20 kg/m 2 ) in a concrete outdoor tank (40 m 2 , 60 m 3 ) supplied by natural seawater (salinity 35 ‰, temperature 20 ± 2 °C).…”

“…The two species are really almost indistinguishable to consumers and are often combined in production and most market statistics (Bjørndal et al, 2016). Regarding common sole, the main investigation areas have been devoted to exploring larval rearing, nutrition of juveniles, egg quality and genetics (Bonvini et al, 2015;Ferraresso et al, 2016;Parma et al, 2013Parma et al, , 2015 while no data on fish flesh quality from farmed specimens are available. The flesh quality of fish is determined by a combination of multiple characteristics including extrinsic factors such as freshness, pre-and post-slaughter handling procedures, (Johnston, 1999;Jonhston et al, 2006) and intrinsic traits such as morphometric characteristics, chemical composition of the flesh and sensory profile attributes (Fuentes et al, 2010;Johnston et al, 2006).…”

Dietary inclusion of mussel meal enhances performance and improves feed and protein utilization in common sole (Solea solea, Linnaeus, 1758) juveniles

“…Subsequently, FAME of all samples, including FO, were separated and quantified as described by Parma et al. ().…”

“…For FM, MM, diets and whole body samples, FAME were prepared by acid-catalyzed transmethylation of total lipids (Christie, 1989). Subsequently, FAME of all samples, including FO, were separated and quantified as described by Parma et al (2015).…”