Kenan Köprücü

The effect of dietary vitamin E on the pleopodal egg number of Astacus leptodactylus (Eschscholtz, 1823)

The effect of vitamin E on the pleopodal egg number of Astacus leptodactylus (Eschscholtz, 1823) was studied. Crayfish were fed 2% of their total wet weight daily with vitamin E supplemented diets and a control for 70 days. The vitamin E content of the control diet, diet 1, diet 2 and diet 3 were 20 mg kg−1, 40 mg kg−1, 80 mg kg−1 and 160 mg kg−1 respectively on a dry weight basis. Vitamin E levels of the control and experimental diets were analysed by High Performance Liquid Chromatography. Results showed that diets containing supplemental vitamin E were associated with an increase in the number of pleopodal eggs. The best result was obtained with diet 2 containing 80 mg kg−1 supplemental vitamin E.

Effect of dietary n-3 polyunsaturated fatty acids on antioxidant defense and sperm quality in rainbow trout (Oncorhynchus mykiss) under regular stripping conditions.

This study examined the effect of dietary n-3 polyunsaturated fatty acids (PUFA) on malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and reduced glutathione (GSH) levels; semen and liver fatty acid compositions; and spermatological values (semen volume and pH, sperm density, percentage and duration of sperm motility) in rainbow trout (Oncorhynchus mykiss) under regular stripping conditions. For this purpose, one control and two experimental diets were prepared as isonitrogenous and isocaloric. The control diet did not contain n-3 PUFA. However, the D1 and D2 diets were supplemented with n-3 PUFA concentrated anchovy oil at a 1% and 2% level, respectively. The n-3 PUFA content in the semen and liver, semen volume, initial sperm motility, duration of 50% sperm motility, total duration of sperm motility and sperm density values of the control fish fed the n-3 PUFA-deficient diet were decreased and were accompanied by a reduction of the antioxidant defense (SOD, CAT, GSH-Px and GSH) and an elevation of MDA in the blood, gonad, liver and kidney at all of the sampling periods (P<0.01 for each case). However, the effects of the sampling period on the MDA and antioxidant defense values in the blood, gonad, liver and kidney of the control diet fish (with the exception of the GSH and GSH-Px activities) and the D1 and D2 diet fish were not significant (P>0.01). However, supplementation with n-3 PUFA protected the fish from these adverse effects. The modulations were clearly observed in the fish fed the D2 diet because they were under lower oxidative stress, as indicated by MDA. The increased enzyme activity corresponds with the physiological mechanisms combating the elevation of free radicals under oxidative stress. The highest n-3 PUFA levels in the semen and liver and spermatological values were obtained from the fish fed the D2 diet at all of the sampling periods. On the other hand, the effects of the sampling stage on the spermatological values of the fish fed the D1 and D2 diets were not significant (P>0.01). However, the effects of the sampling stage in the fish fed the control diet on these values (with the exception of semen pH) were significant (P<0.01). In conclusion, the addition and balance of n-3 PUFA in the diet of broodstock fish can improve sperm quality and ultimately cause successful reproduction.

Effects of dietary propolis on the number and size of pleopadal egg, oxidative stress and antioxidant status of freshwater crayfish (Astacus leptodactylus Eschscholtz)

Four different crayfish diets; control, E1, E2 and E3, respectively containing 0, 1, 2 and 4% propolis, were tested to determine the effects of dietary propolis on the number and size of pleopadal egg, and malondialdehyde (MDA) level, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities in the freshwater crayfish (Astacus leptodactylus). The crayfish were kept at 9.6±5.3°C water temperature and fed three times daily during a six month period The pleopodal egg number (from 7 to 9) produced per gram of the body weight and total pleopodal egg number (from 201 to 263) significantly increased (P<0.05) with the dietary propolis supplemantation. However, an increase in the dietary propolis led to a significant decrease (P<0.05) in the pleopodal egg size (from 3.22mm to 2.76mm). MDA level significantly (P<0.05) decreased in the hepatopancreas (from 4.78 to 3.04 nmol/g protein) and ovarium (from 3.52 to 1.98 nmol/g protein) of the crayfish fed with the increased dietary propolis level. On the other hand, an increase in the dietary propolis led to a significant increase (P<0.05) in SOD activities in hepatopancreas (from 21.8 to 41.1U/g protein) and ovarium (from 16.8 to 26.8U/g protein). However, CAT activities significantly decreased (P<0.05) in the hepatopancreas (from 23.8 to 18.9 nmol/g protein) and ovarium (from 21.8 to 17.5 nmol/g protein) of the crayfish fed with the increased dietary propolis level. Similarly, an increase in the dietary propolis caused a significant decrease (P<0.05) in GSH-Px activities in the hepatopancreas (from 21.8 to 41.1U/g protein) and ovarium (from 16.8 to 26.8U/g protein) with the formation of the pleopodal egg. The dietary propolis improves reproductive efficiency in the crayfish and decreases the oxidative stress under controlled hatchery conditions.