Antioxidant System Response of Freshwater Mussel Anodontacygnea to Cadmium Exposure

Cadmium is one of the widespread toxic substances being hazardous for man as it capable to enter from the environment into animal and plant tissues and spreading along the food chain. We have studied the effect of Cd on the gills and hepatopancreas of the fresh water bivalve mollusks Anodontacygnea. After 12-day acclimation the mollusks were kept for 24 and 72 hours in aquariums with Cd2+ concentrations of 10, 50 and 100 μg/L. Mass-spectrometric analysis has shown that Cd accumulation rate increased with increasing metal concentration in the water. At cadmium concentration of 100 μg/L the mollusk was capable of accumulating up to 0.44 μg of Cd per day. The accumulation of such high metal concentrations in the mollusk tissues did not kill the animals, but signs of oxidative stress, more pronounced in the gills than in the digestive gland, were observed. Exposure to cadmium ions decreased GSH concentration and increase Рx activity in the mollusk gills as early as 24 hours after the beginning of the experiment. Changing the water in the aquarium had a considerable influence on SOD activity in the gills comparable with the effect of the addition of Cd

Survival, Growth Performance, and Hepatic Antioxidant and Lipid Profiles in Infected Rainbow Trout (<i>Oncorhynchus mykiss</i>) Fed a Diet Supplemented with Dihydroquercetin and Arabinogalactan

Natural feed supplements have been shown to improve fish viability, health, and growth, and the ability to withstand multiple stressors related to intensive cultivation. We assumed that a dietary mix of plant-origin substances, such as dihydroquercetin, a flavonoid with antioxidative, anti-inflammatory, and antimicrobial properties, and arabinogalactan, a polysaccharide with immunomodulating activity, would promote fish stress resistance and expected it to have a protective effect against infectious diseases. Farmed rainbow trout fish, Oncorhynchus mykiss, received either a standard diet or a diet supplemented with 25 mg/kg of dihydroquercetin and 50 mg/kg of arabinogalactan during a feeding season, from June to November. The fish in the control and experimental groups were sampled twice a month (eight samplings in total) for growth variable estimations and tissue sampling. The hepatic antioxidant status was assessed via the quantification of molecular antioxidants, such as reduced glutathione and alpha-tocopherol rates, as well as the enzyme activity rates of peroxidase, catalase, and glutathione-S-transferase. The lipid and fatty acid compositions of the feed and fish liver were analyzed using thin-layer and high-performance liquid chromatography. The viability, size, and biochemical indices of the fish responded to the growth physiology, environmental variables such as the dissolved oxygen content and water temperature, and sporadic factors. Due to an outbreak of a natural bacterial infection in the fish stock followed by antibiotic treatment, a higher mortality rate was observed in the fish that received a standard diet compared to those fed supplemented feed. In the postinfection period, reduced dietary 18:2n-6 and 18:3n-3 fatty acid assimilation contents were detected in the fish that received the standard diet in contrast to the supplemented diet. By the end of the feeding season, an impaired antioxidant response, including reduced glutathione S-transferase activity and glutathione content, and a shift in the composition of membrane lipids, such as sterols, 18:1n-7 fatty acid, and phospholipids, were also revealed in fish fed the standard diet. Dietary supplementation with plant-origin substances, such as dihydroquercetin and arabinogalactan, decreases lethality in fish stocks, presumably though the stimulation of natural resistance in farmed fish, thereby increasing the economic efficacy during fish production. From the sustainable aquaculture perspective, natural additives also diminish the anthropogenic transformation of aquaculture-bearing water bodies and their ecosystems

Antioxidant System Response of Freshwater Mussel Anodontacygnea to Cadmium Exposure

Cadmium is one of the widespread toxic substances being hazardous for man as it capable to enter from the environment into animal and plant tissues and spreading along the food chain. We have studied the effect of Cd on the gills and hepatopancreas of the fresh water bivalve mollusks Anodontacygnea. After 12-day acclimation the mollusks were kept for 24 and 72 hours in aquariums with Cd2+ concentrations of 10, 50 and 100 μg/L. Mass-spectrometric analysis has shown that Cd accumulation rate increased with increasing metal concentration in the water. At cadmium concentration of 100 μg/L the mollusk was capable of accumulating up to 0.44 μg of Cd per day. The accumulation of such high metal concentrations in the mollusk tissues did not kill the animals, but signs of oxidative stress, more pronounced in the gills than in the digestive gland, were observed. Exposure to cadmium ions decreased GSH concentration and increase Рx activity in the mollusk gills as early as 24 hours after the beginning of the experiment. Changing the water in the aquarium had a considerable influence on SOD activity in the gills comparable with the effect of the addition of Cd