Vet Res Forum. 2017 Spring; 8(2): 145–153.

Published online 2017 Jun 15.

Mahdi Banaee,^* Vahid Soleimany, and Behzad Nematdoost Haghi

Abstract

This study evaluated preclinical and clinical safety of marshmallow (Althaea officinalis L.) extract as a naturopathic medicine in common carp deliberately infected with Aeromonas hydrophila. The fish were fed 0 (control), 2.50, 5.00 and 10.00 g of marshmallow extract for 60 days in a preclinical experiment and then, challenged with A. hydrophila for a 10-day experiment. Significant increases were observed in aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), creatine phosphokinase (CPK) activities and plasma creatinine levels in fish fed 10 g marshmallow extract per kg feed. However, alanine aminotransferase (ALT) significantly decreased on day 60. The fish fed 2.50 g marshmallow extract per kg feed indicated increased levels of total protein and globulin. There were no significant changes in albumin levels (p > 0.05). 2.50 and 5.00 g marshmallow significantly decreased triglyceride and cholesterol levels and increased glucose levels (p < 0.05). A. hydrophila significantly increased AST, ALT, LDH, ALP and CPK activities and plasma glucose, cholesterol, triglycerides and creatinine levels after 10 days (p < 0.05). Total plasma protein, albumin and globulin levels in fish challenged with A. hydrophila were significantly lower than the control group (p < 0.05). Marshmallow extract at 5.00 and 10.00 g can adjust plasma biochemical parameters in fish challenged with A. hydrophila. The results of preclinical studies and pharmaceutical toxicity of marshmallow extract revealed that dietary levels lower than 5.00 g were safe and effective. The results of this clinical study demonstrated that marshmallow extract (5.00 g kg^-1 feed) can protect fish against A. hydrophila.

Key Words: Aeromonas hydrophila, Biochemical parameters, Common carp, Marshmallow

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Introduction

Aeromonas infection is a serious problem in aquaculture and various antibiotics are used to treat or control fish morbidity. However, the overuse of antibiotics can lead to bacterial resistance and drug residues in final products and environment.¹ Therefore, in recent years, many attempts have been made in veterinary science to replace chemically synthetic drugs with natural medicine.^2–4 One of the most important aspects of veterinary pharmacology is identification and discovery of new drug compounds which can be divided into three phases including discovery, preclinical development and clinical trials.

Medicinal plants have been widely used in folk veterinary medicine for treating or preventing from various diseases in farm animals.^5,6 Herbal products provide an important source of potential medicines and often contain organic compounds with different effects including chemotherapeutic, immune-stimulant, bacteri-ostatic, bactericidal, antifungal and anti-parasitic functions.^3,7,8 In the last two decades, numerous studies have been conducted to determine the feasibility of using herbal medicine in prevention and treatment of aquatic animals’ diseases.^2, 9–11

Marshmallow (Althaea officinalis) is a medicinal plant, the roots, leaves and flowers of which are usually used in traditional medicine in many countries all over the world. This herb contains peptins, starch, monosaccharides, disaccharides, mucilage, flavonoids, anti-oxidants, coumarins, scopoletin, tannin, asparagines and many amino acids. The extracts obtained from the roots and flowers of marshmallow have antibacterial (both Gram-positive and Gram-negative bacteria), antifungal, anti-inflammatory, anti-mycobacterial and anti-cough properties¹² as well as antiviral, anti-yeast, anti-complement¹³ and free radicals scavenging activities. The aqueous extract of marshmallow is also helpful in lowering hyperlipidemia, inflammation, reducing gastric ulcers and inhibiting platelets adhesion without showing any adverse effects on the consumers.^14,15 This plant can also prevent inflammation through inhibition of cytokinins, interleukin-6 and tumor necrosis factor synthesis and/or release. The increases of phagocytic and macrophage activities¹⁶ and the number of T lymphocytes are the main immuno-modulatory effects of the marshmallow root extract. That is why marshmallow would be a good alternative in prevention and treatment of bacterial, viral and fungal infections of aquatic animals.

Therefore, this study was carried out to determine the efficiency of marshmallow extract (Althaea officinalis L.) against experimental infection by Aeromonas hydrophila, so that marshmallow extract might eventually be developed as alternative controls for Aeromonas disease in aquaculture.

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Materials and Methods

Fish preparation and storage conditions. One hundred eighty common carps (average body weight and length: 37.65 ± 4.40 g and 14.15 ± 0.80 cm) were purchased from a private farm (Carp Farm, Shush, Iran) and transferred to the aquaculture laboratory of Aquaculture Department at Behbahan Khatam Al-Anbia University of Technology, Behbahan, Iran. After transferring, 15 fish were randomly allocated to each of 12 fiberglass tanks (300 L) equipped with aeration. Fish were acclimated to the experimental conditions for two weeks (24 ± 2 ˚C; pH: 7.40 ± 0.20; 16 L-8D; 40% water exchange rate per day). During acclimation, fish were fed a commercial diet (Beyza Feed Mill, Shiraz, Iran; including gross energy: 3500 Kcal kg^-1; crude protein: 35 to 37%; crude lipid: 9 to 11%; crude fiber: 5%; moisture: < 10%; ash: < 10%; total volatile nitrogen: < 45 mg per 100 g) twice a day and near to 2% of their respective body weight.

Extract of marshmallow flower. The powder of dried flower of A. officinalis was mixed with distilled water and ethanol (1:1), and the mixture was put on the shaker for 24 hr at room temperature. The resulting hydro-alcoholic extract was filtered through Whatman filter paper and evaporated to dryness on a rotary evaporator until it became creamy and then, dried in an oven at 50 ˚C that finally gave 8 g (8% of initial amount) dried powder. The concentration used in the experiment was based on the dry weight of the extract (Table 1).

Reference:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5524553/