Dietary Ascorbyl Monophosphate Depresses Lipid Peroxidation in Rainbow Trout Spermatozoa

Abstract

This study was designed to analyze lipid peroxidation in spermatozoa of rainbow trout Oncorhynchus mykiss by an optimized thiobarbituric acid (TBA) method, and to evaluate the effect of graded levels of dietary antioxidant (ascorbic acid in the form of ascorbyl monophosphate, AP) on TBA values of spermatozoa . Sperm from rainbow trout fed diets supplemented with AP at 0, 110, or 870 mg/kg were sampled during the reproductive season . The group given the unsupplemented diet had the lowest ascorbic acid concentration in seminal plasma during most of the spermiation season compared with groups fed diets with AP While the ascorbic acid concentration in seminal plasma decreased toward the end of the reproductive season, spermatozoa malondialdehyde production, indicative of increasing peroxidation, tended to increase . At the end of the season, significant differences (P < 0 .05) were found in peroxidation levels in spermatozoa from fish fed different levels of ascorbic acid . The most abundant polyunsaturated fatty acid in sperm lipids, docosahexaenoic acid (C22 :6), was significantly lower in lipids from spermatozoa of the AP-devoid (control) group than in the 870-mg/kg supplement group . By the end of the reproductive season, spermatozoa from the control group had significantly higher peroxidation levels than did spermatozoa from fish given AP (110 and 870 mg/kg) . Thus, it is the first evidence in fish that dietary AP supplements can increase seminal plasma ascorbic acid concentrations, and it suggests that peroxidative damage to spermatozoa can be reduced during the reproductive season, which in turn may affect sperm fertilizing ability .Spermatozoa of sea urchins Strongylocentrotus intermedius, fish, and mammals, including hu-

Dietary antioxidants, but not courtship effort, affect oxidative balance in the testes and muscles of crickets

“…1) and reduced levels of protein oxidation (Fig. 3) compared with those of males fed a diet with only trace amounts of vitamin E. This finding supports the view that, regardless of endogenous antioxidant defences present in the testes (Aitken and Roman, 2008), dietary antioxidants are important components of germline protection (Ahmadi et al, 2016;Liu et al, 1997;Rengaraj and Ho Hong, 2015;Showell et al, 2011;Surai et al, 1997). Our findings cannot be explained in terms of general nutritional resource acquisition and allocation because our completely synthetic diets differed only in the specific micronutrients beta-carotene and vitamin E, and not in macronutrients such as proteins and carbohydrates, the availability of which was standardized across diet treatments.…”

“…While the testes have a battery of endogenous defences to protect the germline from oxidative stress (Aitken and Roman, 2008), dietary antioxidants have also been implicated as limiting resources involved in male reproductive trade-offs (Blount et al, 2001;Dowling and Simmons, 2009). There is good evidence that dietary antioxidants can affect sperm quality (Ahmadi et al, 2016;Liu et al, 1997;Rengaraj and Ho Hong, 2015;Showell et al, 2011;Surai et al, 1997). For example, male three-spined sticklebacks, Gasterosteus aculeatus, fed a diet rich in carotenoids have increased fertilization success in non-competitive fertilization assays (Pike et al, 2010).…”

Ascorbic acid and reproduction in fish: endocrine regulation and gamete quality

“…There are many potential sources of free radicals generated during spermatogenesis, a lipid peroxidation of rich polyunsaturates in differentiating spermatocytes may be responsible for production of oxygen radicals. We recently tested the hypothesis that increased dietary ascorbic acid levels may protect against lipid peroxidation of rainbow trout spermatozoa (Liu, Ciereszko, Czesny & Dabrowski 1997). Doetray ascorbic acid levels of 360 mg kg −1 significantly lowered the amount of malondialdehyde generated by sperm and increased the amount of docosahexaenoic acid in lipids compared with fish on a vitamin C‐deficient diet.…”

Vitamin C - vitamin E interaction in juvenile lake sturgeon (Acipenser fulvescens R.), a fish able to synthesize ascorbic acid

“…Phospholipid peroxidation was promoted using a combination of ferrous sulfate and AA (Aitken et al 1993). Two-hundred-and-sixty pL of microsome suspension were incubated with 8 pL of 0.025 mM FeS04.7 H 2 0 and 8 pL of 0.2 mM AA for 2 hours at 37°C (Liu et al 1997). Two-hundred pL of incubate were added to 360 pL of TBA reaction mixture, and boiled for 30 min in a water bath.…”