Effects of dietary nanoliposome‐coated astaxanthin on haematological parameters, immune responses and the antioxidant status of rainbow trout (Oncorhynchus mykiss)

Abstract

BackgroundAstaxanthin is the most prevalent carotenoid in the marine environment and is widely used as an additive in formulated aquafeeds.ObjectivesA 60‐day feeding trial was conducted to consider the effect of dietary nanoliposome‐coated astaxanthin (NA) on haematological parameters, serum antioxidant activities and immune responses of rainbow trout, Oncorhynchus mykiss.MethodsA total of 450 healthy fish weighing 31.00 ± 2.09 g were randomly assigned in triplicate (30 fish per replicate) to 5 dietary treatments: 0 (control), 25.00, 50.00, 75.00, and 100.00 mg kg−1 NA.ResultsFish fed the diet supplemented with 50.00 mg kg−1 NA exhibited the highest values of red blood cells, white blood cells, haemoglobin and haematocrit of 1.64 ± 0.01 × 106 mm−3, 5.54 ± 0.21 × 103 mm−3, 8.73 ± 0.24 g dL−1 and 46.67% ± 0.88%, respectively, which were significantly higher than those fed the basal diet (p < 0.05). The lowest and highest percentages of lymphocytes (67.67% ± 0.33%) and neutrophils (27.33% ± 1.20%) were also obtained in fish fed 50.00 mg kg−1 NA compared to those fed the basal diet (p < 0.05). Fish receiving diet supplemented with 50.00 mg kg−1 NA revealed the highest serum activity in superoxide dismutase, catalase, glutathione peroxidase, lysozyme and alternative complement and the lowest level of total cholesterol, cortisol, aspartate aminotransferase and alanine aminotransferase than fish receiving the basal diet (p < 0.05). Serum immunoglobulin (Ig) and ACH50 contents significantly increased with increasing dietary NA supplementation to the highest values of 43.17 ± 1.46 and 293.33 ± 2.03 U mL−1, respectively, in fish fed diet supplemented with 50 mg kg−1 NA (p < 0.05).ConclusionsSupplementation of NA in rainbow trout diet at 50 mg kg−1 exhibited a positive effect on haematological parameters, antioxidant capacity and immune responses. Administration of such dosage can enhance rainbow trout immune responses against unfavourable or stressful conditions, for example disease outbreaks, hypoxic condition, thermal stress and sudden osmotic fluctuations, which usually happen in an intensive culture system.

Generation of Porcine and Rainbow Trout 3D Intestinal Models and Their Use to Investigate Astaxanthin Effects In Vitro

“…Thanks to these properties, AST finds applications in pharmaceutical, nutraceutical, and cosmetic industries, with various health benefits in humans [ 6 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. In fish, pigs, and broilers, this compound is used as a pigmenting additive, to confer on animals their distinctive and commercially valued skin and fillet color appearance, directly associated with the final product quality [ 4 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. In addition, this carotenoid is a useful supplement in piglet diets, due to its ability to reduce intestinal inflammation and to boost the immune system during the weaning period, when young animals are exposed to a number of stressors [ 29 ].…”