Microalgae feed additives improve growth, immunity, and resistance to Vibrio anguillarum infection in juvenile rainbow trout, Oncorhynchus mykiss

Authors

1 Major of Aquaculture and Applied Life Sciences, Division of Fisheries Life Sciences, Pukyong National University, Busan 48513, Republic of Korea

2 Universidad Científica del Sur, Lima 15067, Peru

3 CJ Feed & Care, Seoul 04560, Republic of Korea

4 Aquaculture Research Institute, University of Idaho, Hagerman, ID 83332, USA

5 Aquafeed Research Center, National Institute of Fisheries Science, Pohang 37517, Republic of Korea

6 East Sea Branch, Korea Fisheries Resources Agency, Pohang 37601, Republic of Korea

7 Feeds and Foods Nutrition Research Center, Pukyong National University, Busan 48547, Republic of Korea

10.22092/ijfs.2024.131267

Abstract

The present study was conducted to evaluate the effects of three different dietary microalgae on growth, intestinal histology, immune biomarkers, and resistance to a bacterial pathogen (Vibrio anguillarum) in juvenile rainbow trout, Oncorhynchus mykiss. Four experimental diets were prepared, including a basal diet (CON) and three diets containing Chlorella sp. (CHL), Haematococcus sp. (HAE), or Schizochytrium sp. (SCH), at 0.5% for each microalga which was supplemented in the basal diet. A total of 180 juvenile rainbow trout with an initial body weight of 12.16±0.01 g (mean±SD) were randomly distributed into 12 tanks and reared by the semi-recirculation system. After six weeks of the feeding trial, the weight gain (99.4%), specific growth rate (1.92%/day), and myeloperoxidase activity (5.08), of the fish fed the HAE were significantly higher than those of fish fed the other diets (p<0.05). The intestinal villus length of the fish fed the HAE diet (1.34 µm) was significantly higher than that of those fed the CHL (1.13 µm) and CON (1.14 µm) diets. The cumulative survival rates (CSR) were recorded for 27 days after intraperitoneal injection of the bacterial pathogen V. anguillarum. The CSR of the fish fed the HAE diet (75%) was significantly higher than that of those fed the other diets. It is suggested that Haematococcus sp. (0.5% inclusion in the diet) may improve weight gain, specific growth rate, intestinal villus length, and myeloperoxidase activity as well as increase the survival rate of juvenile rainbow trout against the V. anguillarum challenge.

Keywords

Iranian Journal of Fisheries Sciences
Volume 23, Issue 4
July 2024
Pages 537-557

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