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

•The freshwater crayfish under the controlled conditions was used in this study.•Dietary propolis is effective on the pleopodal egg production of freshwater crayfish.•The dietary supplementation of propolis could reduce the oxidative stress in the crayfish.•The highest pleopodal egg number and antioxidant capacity were obtained from the crayfish fed the E3 diet.

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 3.22 mm to 2.76 mm). 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 41.1 U/g protein) and ovarium (from 16.8 to 26.8 U/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 41.1 U/g protein) and ovarium (from 16.8 to 26.8 U/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.