Chlorella sp. and Nannochloropsis sp. Inclusion in Plant-Based Diets Modulate the Intestine and Liver Antioxidant Mechanisms of European Sea Bass Juveniles

Abstract

This study aimed to evaluate the effects of including microalgae Chlorella sp. or Nannochloropsis sp. in plant-based diets on antioxidant mechanisms of European sea bass (Dicentrarchus labrax) juveniles. For this purpose, three isoproteic (50%) and isolipidic (19%) diets were formulated: a practical diet, containing 15% fish meal (FM) and plant ingredients as the protein source and a mixture of fish oil and vegetable oils (40: 60) as lipid source (control diet); and two diets identical to the control but with the FM replaced by Nannochloropsis sp. or Chlorella sp. (diets Nanno and Chlo, respectively). The diets were offered to quadruplicate groups of 25 fish (initial body weight: 24 ± 1 g) for 11 weeks and then enzymatic and non-enzymatic antioxidant mechanisms and lipid oxidative biomarkers were assessed in the liver and intestine of these fish. Results showed that the antioxidant response was tissue-dependent, with the liver exhibiting lower glutathione peroxidase and glucose-6-phosphate dehydrogenase (only in Chlo group) activities, and intestine lower superoxide dismutase activity with the diets including microalgae compared to control diet. An increase of oxidized glutathione content was also observed in the intestine of fish fed the microalgae diets. Catalase and glutathione reductase activities, oxidative stress index, and total and reduced glutathione, were unaffected by dietary treatments in both tissues. Overall, the lipid peroxidation status was not compromised by the replacement of FM by microalgae.

Potential application and beneficial effects of a marine microalgal biomass produced in a high-rate algal pond (HRAP) in diets of European sea bass, Dicentrarchus labrax

“…The main microalgal cultured genera are Chlorella , Nannochloropsis , Scenedesmus , Arthrospira , Tisochrysis , and Tetraselmis (Sirakov et al 2015 ; Bleakley and Hayes 2017 ), thanks to their nutritional and health properties and consolidated cultivation technology. Recently, Castro et al ( 2020 ) have proved that the inclusion up to 15 % of Nannochloropsis sp. in diets for European sea bass has decreasing effects on the liver and intestinal antioxidant activity, while Abdelghany et al ( 2020 ) have demonstrated that dietary N. oculata significantly improves growth parameters and resistance to pathogens such as Aeromonas veronii in Nile tilapia ( O. niloticus ).…”

Functional Feeds to Tackle Meagre (Argyrosomus regius) Stress: Physiological Responses under Acute Stressful Handling Conditions

“…Until now, most studies conducted with fish tested whole algae rather than algal extracts [12,21,22]. This can compromise the potential efficiency of bioactive compounds as algae have rigid cell walls that are hard to digest, particularly by carnivorous fish, therefore limiting the availability of several active compounds.…”

Chlorella vulgaris Extracts as Modulators of the Health Status and the Inflammatory Response of Gilthead Seabream Juveniles (Sparus aurata)

“…CTR D1 D2 D3 Fishmeal Super Prime 1 10.00 10.00 10.00 10.00 Fish gelatin 2 2.00 2.00 2.00 2.00 Soy protein concentrate 3 10.00 10.00 10.00 10.00 Wheat gluten 4 7.00 7.00 7.00 7.00 Corn gluten 5 15.00 15.00 15.00 15.00 Soybean meal 6 20.00 20.00 20.00 20.00 Rapeseed meal 7 5.25 5.25 5.25 5.25 Sunflower meal 8 5.00 5.00 5.00 5.00 Wheat meal 9 7.00 5.00 7.00 7.00 Fish oil 10 4.90 4.90 4.90 4.90 Soybean oil 11 9.10 9.10 9.10 9.10 Premix 1% 12 1.00 1.00 1.00 1.00 Binder (Celatom-Diatomite) 13 1.00 1.00 1.00 1.00 MAP (Monoammonium phosphate) 14 1.50 1.50 1.50 1.50 L-Lysine 15 1.00 1.00 1.00 1.00 L-Threonine 16 0.10 0.10 0.10 0.10 DL-Methionine 17 0.15 0.15 0.15 0.15 Chlorella whole biomass-Algafarm 18 0.00 2.00 0.00 0.00 Chlorella-soluble fraction 19 0.00 0.00 0.10 0.00 Chlorella-Insoluble residue 20 0.00 0.00 0.00 0.10…”