Folic Acid-Coated Nanochitosan Ameliorated the Growth Performance, Hematological Parameters, Antioxidant Status, and Immune Responses of Rainbow Trout (Oncorhynchus mykiss).

Sahar Farahnak Roudsari,Seyed Abdolmajid Mousavi,Houman Rajabi Islami,Mehdi Shamsaie Mehrgan

doi:10.3389/fvets.2021.647722

Abstract

In recent years, chitosan has gained considerable attention due to its favorable properties such as excellent biocompatibility and biodegradability for which it can be used as a health supplement for delivering bioactive compounds in the food industry and nutrition. In the present study, the effect of nanochitosans coated with folic acid (FA) was considered on the growth performance, hematological parameters, antioxidant status, and serum immune responses of rainbow trout (Oncorhynchus mykiss) fingerlings. Graded levels of FA-coated nanochitosan (0, 0.1, 0.25, 0.5, and 1 mg kg−1 diet) were added to the basal diet, and each experimental diet was fed to three groups of fish with an approximate weight of 31 g for 8 weeks. The experimental study demonstrated that dietary FA-coated nanochitosan significantly (P < 0.05) improved the weight gain ration (WGR), specific growth rate (SGR), and feed conversion ratio (FCR) of fish at the end of the feeding trial. There were also linearly increasing trends in red blood cells (RBCs), white blood cells (WBCs), hemoglobin (Hb), and hematocrit (Hct) of fish fed with increasing dietary chitosan/FA levels, whereas no significant difference was recorded in differential leukocyte count of fish among the treatments. In case of antioxidant responses, fish fed diet supplemented with 0.50 mg kg−1 FA-coated nanochitosan had the highest CAT and SOD activities, while the maximum activity of GPX was found in fish fed diet supplemented with 1.00 mg kg−1 FA-coated nanochitosan. Malondialdehyde activity also reached the lowest value in fish fed with 1.00 mg kg−1 FA-coated nanochitosan-supplemented diet (P < 0.05). Measured immune responses showed a linear augmentation in lysozyme activity (LA) with increasing dietary FA-coated nanochitosan, while linearly and quadratically increasing trends were recorded in immunoglobulin M (IgM) content as well as complement component C3 and C4 activities by increasing the supplementation of nanochitosan coated with FA (P < 0.05). Findings of the current study illustrated the positive effect of dietary FA-coated nanochitosan as a promising compound on improving the growth performance, feed utilization, antioxidant status, and immune responses of rainbow trout.

Highlights

Folic acid (FA) is the completely oxidized form of vitamin B9 that plays essential roles in key metabolic pathways involved in purine and pyrimidine synthesis, amino acid metabolisms, methylation reactions, and formate generation [1, 2]
In comparison with the nanochitosan diagram, the FA-coated nanochitosan spectra have a significant difference at 1687.97 cm−1, which may be due to the formation of the amide bond between the amino group of chitosan and the carboxyl group of folic acid
Folate is a key component with profound impact on the cellular metabolism, growth, and proliferation by providing one carbon unit for numerous biochemical reactions involved in the synthesis of DNA, amino acids, creatine, and phospholipids [38, 39]

Summary

Introduction

Folic acid (FA) is the completely oxidized form of vitamin B9 that plays essential roles in key metabolic pathways involved in purine and pyrimidine synthesis, amino acid metabolisms, methylation reactions, and formate generation [1, 2]. It consists of an aromatic pteridine ring linked through a methylene bridge to paraaminobenzoic acid and glutamate to form FA [3], which acts in a variety of physiological processes such as cell multiplication, protein methylation, gene activity regulation, and red blood cell creation after conversion to active tetrahydrofolate [4, 5]. Based on the latest published statistics, about 814 thousand tons of rainbow trout are cultured by 80 countries such as Japan, Iran, United States, Chile, Norway, Denmark, Turkey, Italy, and Germany with the global production value of more than 3.6 million U.S dollars [20]

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Results

Conclusion