Antifungal activity of sodium chloride on Saprolegnia diclina and Aphanomyces sp.

Abstract

Sixteen identified and three unidentified species belonging to six genera of zoosporic fungi were isolated from forty water samples which were collected from different fish and fish hatcheries farms at Abbassa city, Sharkiya governorate, Egypt, using sesame seeds baiting technique at 20±2°C. Saprolegnia and Achlya contributed the broadest spectra of species diversity amongst the other genera of zoosporic fungi. Saprolegnia diclina and Aphanomyces sp. were the most prevalent species of zoosporic fungi. The abundance of zoosporic fungal species in these aquacultures was correlated with some physicochemical characteristics of the water samples. The two dominant species of zoosporic fungi were tested for their tolerance of NaCl solution and its impact on some morphological and metabolic activities of these fungi. Saprolegnia diclina tolerated concentrations of NaCl solution till 12000 μg/ml whereas the maximum resistance of Aphanomyces sp. was 8000 μg/ml. The examined morphological aspects of the two studied fungal species, which included the colony diameters, the vegetative hyphae, zoosporogenesis, zoospores discharge, sexual reproductive structures and gemmae formation, were generally affected depending upon the tested fungal species and the applied dose of NaCl solution. The low treatments of NaCl solution were significantly stimulative compared with the control for protease production by S. diclina but higher doses were significantly suppressive. A significant decline in protease activity at all applications was found when Aphanomyces sp. was treated with NaCl solution. The total free amino acids and total protein content of S. diclina and Aphanomyces sp. mycelia were almost significantly increased relative to untreated controls at the low dose of NaCl solution and they were significantly dropped at the higher concentrations by the two zoosporic fungi.

The in vitro antifungal activity of 30 Chinese herb extracts to Saprolegnia sp.

“…With restrictions on the use of malachite green, more emphasis has been directed toward identifying suitable alternatives. Alternative antifungal agents have focused mainly on three candidates: formalin (Barnes and Soupir, 2006;Akpoilih and Adebayo, 2010), hydrogen peroxide (Rach et al, 2004;Mitchell et al, 2009;Matthews et al, 2012), and sodium chloride or seawater (Waterstrat and Marking, 1995;Koeypudsa et al, 2005;Ali, 2009). Formalin is widely used as a topical treatment for saprolegniosis; however, it has the potential of being toxic, particularly at temperatures above 25°C (Akpoilih and Adebayo, 2010) and reported dosages of 50-150 mg L À1 (Barnes and Soupir, 2006;Akpoilih and Adebayo, 2010), and is impractical for use in large ponds.…”

Straminipiles fungi growing on the alevins of the Nile tilapia in limnologically and trophically different water bodies

“…The occurrence of zoosporic fungi has been investigated in bodies of water that are the areas of natural distribution of Nile tilapia on the African continent, mainly in the Northern part of the continent, especially in upper Egypt (Khallil et al, 1993) and lower Egypt (Ali, 2007(Ali, , 2009. Zoosporic fungi were collected from accumulated rainfall water (El-Nagdy and Nasser, 2000), ponds in oases (El-Nagdy and Abdel-Hafez, 1990), the Nile River (El-Hissy et al, 1982), Nile Delta Region waters (El-Hissy and Khallil, 1989;Ali, 2007), Lake Nasser on the Aswan High Dam (El-Hissy et al, 2000), and other Egyptian lakes (Ali and Abdel-Raheem, 2003;El-Hissy et al, 2004), and fungal zoosporic species belonging to the Saprolegnia, Pythium, Phytophthora, and Achlya genera were found.…”

Ecological diversity and economical importance of species from Aphanomyces genus

“…The occurrence of Aphanomyces species has been registered in water bodies of African continent by El-Sharouny and Badram (1985), Shaheen et al (1999), El-Hissy et al (2004) and Ali (2009). Aphanomyces species have been associated with skin lesions and mortality of some fish species.…”