Single or combined consumption of resveratrol and the probiotic, Lactobacillus acidophilus attenuate the effects of crowding stress on growth, immune characteristics, and antioxidant defense in the common carp, (Cyprinus carpio)

In the present study, dietary resveratrol (RE) and Lactobacillus acidophilus (LAB) were individually or combined added to the diet of common carp (Cyprinus carpio) to protect against crowding stress. Fish (30.16 ± 0.7; Mean ± SE) were randomly allocated to seven groups in three replicates, as follows: T1: basic food as control, T2: LAB with a concentration of 1.5 × 107 CFU/g, T3: LAB with a concentration of 3 × 107 CFU/g, T4: 300 mg resveratrol/kg, T5: 600 mg resveratrol/kg, and T6: 1.5 × 107 CFU/g + 300 mg resveratrol/kg and T7: 3 × 107 CFU/g + 600 mg resveratrol/kg. After 60 days feeding, the supplemented fish had the highest final body weight (FBW), weight gain (WG), and specific growth rate (SGR), and the lowest feed conversion ratio (FCR) as compared with the control group (P < 0.05). The activities of amylase, protease and lipase were noticed markedly higher in fish supplemented with 1.5 × 107 CFU/g + 300 mg resveratrol/kg and 1.5 × 107 CFU/g diets compared to the control (P < 0.05). Generally, fish in supplemented diets, particularly T2 and T6 groups, had the highest lysozyme, alternative complement activity (ACH50), total immunoglobulin (Ig), nitroblue tetrazolium test (NBT), myeloperoxidase (MPO), complement component 3 (C3), complement component 4 (C4), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and lower levels of malondialdehyde (MDA), glucose, cortisol, alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) when were compared with the control before crowding stress (P < 0.05). After crowding stress challenge, fish in the supplemented groups, particularly T2 and T6, generally showed significantly higher values of lysozyme, ACH50, total Ig, NBT, MPO, C3, C4, SOD, CAT, GPx and lower levels of MDA, glucose, cortisol, ALT, ALP, LDH when compared with the control (P < 0.05). Also, recovered fish in the control group demonstrated significantly declined levels of lysozyme, ACH50, total Ig, NBT, MPO, C3, C4, SOD, CAT, GPx and higher levels of MDA, glucose, cortisol, ALT, ALP, LDH as compared to other group (P < 0.05). In conclusion, a combined administration of RE and LAB effectively improved growth performance and health status as well as protected common carp against crowding stress.