Ascorbic acid ameliorated the sperm quality of rainbow trout (Oncorhynchus mykiss) against arsenic toxicity: Impact on oxidative stress, fertility ability and embryo development.

Arsenic (As) is a heavy metal and aquatic pollutant and adversely impacts the reproduction of male fish. As a chain-breaking antioxidant, ascorbic acid (AA) has high water solubility and low toxicity. In this context, the current study was performed to assess the protective role of AA (1 mM) on the sperm cells of the rainbow trout (Oncorhynchus mykiss) exposed to sublethal concentrations of As (8, 16 and 32 mg/L). Sperm quality parameters were analyzed using a sperm class analyzer system. Lipid peroxidation and antioxidant enzyme levels were used as indicators of oxidative stress. The fertilization, eyeing and hatching rates were determined as gamete markers. Reduced sperm quality parameters and fertility capacity resulted from in vitro exposure to As (P < 0.05). The oxidative stress in sperm cells increased after As exposure (P < 0.05). The presence of AA improved sperm movement parameters and fertility potential (P < 0.05). Overall, AA had a positive effect on oxidative stress and fertility ability against As toxicity and AA supplementation ameliorated detrimental effects of As in sperm cells.

Improvement of sperm motility of Oncorhynchus mykiss and Salvelinus fontinalis by L-tryptophan.

Experiments were designed to test the influence of L-tryptophan supplementation of the extender on the sperm motility parameters and bacterial flora of brook trout (Salvelinus fontinalis) and rainbow trout (Oncorhynchus mykiss). The extender containing 0.3 M glucose in 10% Dimethyl sulfoxide (DMSO) was supplemented with 0, 0.5, 1, 2, and 4 mM L-tryptophan. Sperm samples stored for up to 12 days at 4°C for brook trout were motile while motility was not observed after six days of storage for rainbow trout. Diluted sperm samples were spread-plated onto Plate Count Agar (PCA) (Total Bacteria Count), Rose Bengal Agar (RBC) (Yeast-Mold Count), Violet Red Bile Dextrose (VRBD) (Enterobacteriaceae count) and Mannitol Salt Agar (MSA) (Micrococcus/Staphylococcus count) and counts were performed in duplicate and sampling occurred on day 0, 2, 4, 6, and 12 of cold storage. L-tryptophan supplementation of the extender yielded a positive effect, significantly prolonging sperm motility in S. fontinalis and O. mykiss compared to the control group (p < 0.05). The ideal results were obtained above a concentration of 0.5 mM for both species. Total bacteria count in fresh sperm (undiluted samples) was not detectable and not detected in sperm samples treated with different L-tryptophan concentrations. Yeast-mold, Enterobacteriaceae and Micrococcus/Staphylococcus were not detected from fresh and treated sperm brook trout and rainbow trout. On the basis of the results, L-tryptophan-based extender is useful for maintaining sperm quality in short-term storage. L-tryptophan had a negative effect on the bacterial flora. The results of the current study encourages further studies related to long-term storage and reproduction management. Abbreviations: DMSO: dimethyl sulfoxide; PCA: plate count agar; RBC: rose Bengal agar; VRBD: violet red bile dextrose; MSA: mannitol salt agar; SCA: sperm class analyzer; CFU: colony-forming unit.

Determination of bioaccumulation of heavy metals and selenium in tissues of brown trout Salmo trutta macrostigma (Duméril, 1858) from Munzur Stream, Tunceli, Turkey.

The objective of the present work was to determine the bioaccumulation of arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), mercury (Hg), uranium (U) and selenium (Se) in gill, liver, and muscle tissues of the fresh water fish Salmo trutta macrostigma (Duméril, 1858) in Munzur Stream, Tunceli, Turkey. The highest concentrations of U (1.83 µg kg(-1)), Pb (119.84 µg kg(-1)) and Se (1.31 µg kg(-1)) were recorded in the gills of S. t. macrostigma. Concentrations of As (46.27 µg kg(-1)), Cd (109.19 µg kg(-1)), Hg (16.40 µg kg(-1)), Cu (18.19 µg kg(-1)) were recorded at highest levels in the liver. The results showed that there were significant differences in concentrations of As, Cd, Cu, Pb, Se, U and Hg in gill, liver and muscle tissue (p < 0.05). Heavy metals were within the edible parts of the investigated fish were in the permissible safety levels for human uses.