Growth performance and gene expression in gilthead sea bream (Sparus aurata) fed microdiets with high docosahexaenoic acid and antioxidant levels

Abstract

This study aimed to determine the effects of increasing docosahexaenoic acid (DHA) levels in Sparus aurata diets supplemented with antioxidants vitamins (vitamins C and E). Six isoproteic and isolipidic formulated diets, which varied in the DHA content (38-78 g kg À1 TFA), were fed to 19 dph S. aurata larvae. No significant differences were found in survival rates or growth, which indicates that all the diets covered the minimum essential fatty acid requirements of this species. Stress resistance was not negatively affected by dietary DHA contents. In agreement, two biomarkers of the oxidative stress of the fish and the gene expression of superoxide dismutase and glutathione peroxidase were not affected by the elevation of dietary DHA, denoting that fish were sufficiently protected from oxidative damage even at high dietary DHA contents. The elevation of dietary DHA did affect neither the occurrence of skeletal malformations nor the expression of osteological markers such as run-related transcription factor 2 or alkaline phosphatase. The results of this study have confirmed that increase of the dietary DHA levels in gilthead sea bream diets does not negatively affect larval performance if the larvae are protected from peroxidation risks. Despite not being harmful, increase of DHA over the recommended requirements does not have any significant improvement in larval performance.

Effect of increasing docosahexaenoic acid content in weaning diets on survival, growth and skeletal anomalies of longfin yellowtail (Seriola rivoliana,Valenciennes 1833)

“…On the other hand, inclusion of dietary DHA did not significantly affect S. rivoliana larval growth. Similar results have been reported in other marine teleost species, such as S. aurata (Hernández‐Cruz et al., ; Izquierdo et al., ), P. pagrus (Roo et al., ), Coryphaena hippurus (Kraul, ) and Centropomus parallelus (Seifert, Cerqueira & Madureira, ), where fish performance was not influenced by increasing dietary levels of DHA. Contrarily to what could be expected taking into account other studies from the Seriola genus (Furuita, Takeuchi, Watanabe et al., ; Matsunari et al., ; Takeuchi et al., ), larval growth was slightly higher among the larvae fed the lowest DHA dietary content (Diet DHA0; 0.25% DHA, dw), albeit no significant differences were observed.…”

“…The inclusion of dietary DHA in inert diets up to 3.71% (dw) increased the final survival in S. rivoliana larvae (81.5%), being higher than previous studies with other marine finfish species such as 25% (Eryalçin et al., ), 45% (Saleh et al., ) and 48% (Hernández‐Cruz et al., ) in S. aurata or 49% (Betancor, Caballero, Terova, Corà et al., ) and 73% in D. labrax (Cahu, Zambonino‐Infante & Takeuchi, ). In agreement, larvae from species from the same genus fed live preys enriched with DHA displayed enhanced final larval survival (Furuita, Takeuchi, Watanabe et al., ; Ishizaki, Takeuchi, Watanabe, Arimoto & Shimizu, ; Matsunari et al., ; Takeuchi, Ishizaki, Watanabe, Imaizumi & Shimizu, ; Yamamoto et al., ).…”

“…In this sense , a comparison between reared and wild specimens of S. quinqueradiata determined that the triglycerides content observed in reared fish was higher than in wild fish, as well as the amount of n − 3 PUFA, particularly DHA (Arakawa et al., ). Curiously, in other marine teleost species, increased DHA levels did not result in alterations in the total SFA content in larvae (Hernández‐Cruz et al., ; Izquierdo et al., ).…”

Feeding frequency and dietary protein/carbohydrate ratio affect feed intake and appetite regulation-related genes expression in gilthead seabream (Sparus aurata)

“…However, no other significant differences were observed regarding gene expression, which might be connected with the observed high standard deviations, not allowing to make stronger conclusions. These high variation in appetite-relates genes expression was already presented in some other studies (Hernández-Cruz et al, 2015;Perelló-Amorós et al, 2018;Torrecillas et al, 2021). Moreover, due to the small fish size and as previously done in other studies on appetite regulation in gilthead seabream we analyzed the whole-brain (Babaei et al, 2017;Perelló-Amorós et al, 2018;Basto-Silva et al, 2021;Pulido-Rodriguez et al, 2021).…”

Optimizing Artemia Enrichment: A Low DHA/High EPA Protocol for Enhanced n-3 LC-HUFA Levels to Support Greater Amberjack (Seriola dumerili) Larval Rearing

“…Most published studies report that DHA is more limiting for growth, survival, and nervous system and schooling behavior development than EPA [ 15 , 36 ]. On the contrary, other studies identify high levels of dietary DHA as a cause of muscular dystrophy [ 37 ] or spinal anomalies in larvae [ 38 ] due to the high peroxidation risk of DHA and the formation of toxic oxidized compounds, if they are not properly protected with antioxidant substances [ 18 , 35 ].…”