Synergistic effects of dietary selenium nanoparticles and vitamin C improve growth performance, immune response, and antioxidant status of juvenile common carp (Cyprinus carpio).

INTRODUCTION: This study aimed to investigate the synergistic effects of dietary selenium nanoparticles (Se-NPs) and vitamin C (VC) on growth, body composition, antioxidant defense, immunity, and serum biochemical indexes of common carp (Cyprinus carp) juveniles. METHODOLOGY: The test diets were supplemented with three levels of Se-NPs (0, 0.5, and 1 mg/Kg) and three levels of VC (0, 500, and 1000 mg/Kg): the basal diet without supplemental Se-NPs and VC (VC0SeNPs0; control), 0.5 mg Se-NPs /Kg (VC0SeNPs0.5), 1 mg Se-NPs /Kg (VC0SeNPs1), 500 mg VC/Kg (VC500SeNPs0), 1000 mg VC/Kg (VC1000SeNPs0), 500 mg VC/Kg and 0.5 mg Se-NPs (VC500SeNPs0.5), 1000 mg VC/Kg and 0.5 mg Se-NPs (VC1000SeNPs0.5), 500 mg VC/Kg and 1 mg Se-NPs (VC500SeNPs1), 1000 mg VC/Kg and 1 mg Se-NPs (VC1000SeNPs1). The fish were randomly divided into nine experimental groups in triplicate tanks per treatment and fed on their respective diets for 60 days. RESULTS: The findings displayed that fish fed with VC500SeNPs1 and VC500SeNPs0.5 diets had significantly (P < 0.05) higher specific growth rates when compared to other groups. The lowest feed conversion ratio was detected in the VC1000SeNPs1 group and the highest in the control group (P < 0.05). VC, Se-NPs, and their interaction had no significant effect on serum malondialdehyde, ACH50, and IgM (P > 0.05). However, the best parameters associated with antioxidant capacity (higher serum levels of superoxide dismutase and total reduced glutathione) and physiological status (higher concentration of serum globulin and lower amounts of aspartate aminotransferase and lactate dehydrogenase) belonged to the VC1000SeNPs1 and VC500SeNPs1 groups. The results suggest that the Se-NPs and VC combination more efficiently influence the common carp's growth performance, antioxidant status, immunity, and physiological parameters. CONCLUSION: Overall, the diet enriched with 500 mg VC and 1 mg Se-NPs /Kg (VC500SeNPs1) is suitable for boosting the growth and immunity of common carp.

Lacticaseibacillus casei in Diet of Juvenile Convict Cichlid Fish (Amatitlania nigrofasciata): Evaluating Growth Performance, Digestive Enzyme Activities, Immune Responses, and Stress Resistance.

In this study, growth performance, body composition, digestive enzymes activity, mucosal and immunological parameters, cultivable bacterial populations, and stress resistance were investigated in juvenile convict cichlid fish (Amatitlania nigrofasciata) that received a dietary supplement containing 0 (control), 5 × 106 (LC1), 5 × 107 (LC2), and 5 × 108 CFU g-1 diet (LC3) Lacticaseibacillus casei PB-LC39. Two hundred and forty fish (2.44 ± 0.04 g) were assigned to twelve experimental aquariums and feed ad libitum three times a day for 8 weeks. After final sampling, final body weight, percentage of weight gain (WG %), specific growth rate (SGR), food conversion ratio (FCR), and protein content of whole-body composition were significantly higher (P < 0.05) in fish fed LC1 diet than other treatments. Total protease, amylase, and lipase activities were also significantly higher (P < 0.05) in fish fed LC1 diet than other groups. Total protein from serum and mucus, lysozyme activity, total immunoglobulin (Ig), and serum globulin were significantly increased (P < 0.05) in fish fed LC1 diet compared with other groups. Moreover, total counts of lactic acid bacteria (LAB) in fish gut were significantly higher (P < 0.05) by different levels of L. casei PB-LC39 than the control group. Recovery rates of fish fed the probiotic cells, after an air-dive test, was significantly increased (P < 0.05) compared with the control group. Therefore, the results showed that L. casei PB-LC39 resulted in improving growth, health status, and stress resistance of fish during the rearing of juvenile convict cichlid fish.