The effects of dietary galactooligosaccharide on innate immune response and stress resistance of Narrow clawed crayfish (Astacus leptodactylus Eschscholtz, 1823)

The aim of this study was to evaluate the ability of dietary prebiotic galactooligosaccharide (GOS) on the innate immune response and stress resistance of narrow clawed crayfish (Astacus leptodactylus). To this purpose, 120 crayfishes (27.88 ± 0.27) randomly distributed into 12 fiberglass tanks at a density of 10 crayfish per tank. Crayfish fed with different GOS-enriched diets (0, 1, 2 and 3%) two times a day (9 am and 4 pm) at the rate of 1.5 % of body weight. At the end of a 97-day feeding trial, crayfish fed 2% GOS supplemented diets had significantly higher total haemocyte count (THC), semi-granular cell (SGC) and hyaline cell (HC) counts compared to the other groups (P < .05). Moreover, the highest catalase (CAT) activity was observed in crayfish fed 3% GOS-enriched diet while the highest lysozyme (LYZ) activity was detected in treatments fed 2 and 3% enriched diets (P < .05). Furthermore, 24-h post exposure to air, dietary GOS supplemented diet could significantly improve the THC, SGC and HC count in crayfish fed 1 and 2% GOS as well as CAT activity in 3% GOS-supplemented group (P < .05). Based on present results, dietary GOS-enriched diets as prebiotic could beneficiary modulate innate immune response as well as stress resistance of A. leptodactylus.