RESUMEN
The aim of this study was to investigate the synbiotic effects of Pediococcus acidilactici (PA) and isomaltooligosaccharide (IMO) on the performance of juvenile common carp (Cyprinus carpio). A total of 360 fish (17.22 ± 0.19 g) were randomly divided into six groups with three replicates of 20 fish each. The trial continued for 8 weeks. The control group was fed only basal diet; PA was fed basal diet supplemented with 1 g/kg (1010 CFU/kg) PA, IMO5 (5 g/kg IMO), IMO10 (10 g/kg IMO), PA-IMO5 (1 g/kg PA and 5 g/kg IMO), and PA-IMO10 (1 g/kg PA and 10 g/kg IMO). The results indicated that the diet containing 1 g/kg PA and 5 g/kg IMO significantly increased the fish growth performance and decreased the feed conversion ratio (p < 0.05). Overall, blood biochemical parameters, serum (lysozyme, complements C3 and C4) and mucosal (protein, total immunoglobulin, and lysozyme) immune responses, and antioxidant defense of fish also improved in the PA-IMO5 group (p < 0.05). Therefore, a combination of 1 g/kg (1010 CFU/kg) PA and 5 g/kg IMO can be recommended as a beneficial synbiotic additive and immunostimulant in juvenile common carp.
RESUMEN
In this study, chitosan coatings incorporated with propolis extract (PE) were utilized to extend the shelf-life of refrigerated Nemipterus japonicus fillets. Microbiological (total mesophilic bacteria (TMB) and total psychrotrophic count (TPC)), physicochemical (pH, total volatile bases nitrogen (TVB-N), 2-thiobarbituric acid reactive substances (TBARS), free fatty acid (FFA)) and sensory (color, odor and preference) characteristics of coated fillets were evaluated during 12days. The results showed that incorporating PE into chitosan solution could significantly (P<0.05) improve the quality of fish fillets. The results showed that the chitosan+PE samples reduced the extent of lipid oxidation, as judged by TBARS and FFA, suggesting that there is a synergistic effect between chitosan coating and propolis. Moreover, the application of chitosan coatings with PE improved the TVB-N and pH values of the Nemipterus japonicus samples significantly compared to untreated sample, thus extending the shelf life of Nemipterus japonicus fillet approximately >10days. All wrapped fillets in treatment samples incorporated with PE had lower bacterial counts compared to control (P<0.05). However, the bacterial counts of chitosan coating combined with PE were lower than those treated by chitosan or PE alone during the storage. The fillets treated with chitosan and PE had the best sensory properties. The increase (>10days) in the shelf-life was attributed to the antioxidant and antimicrobial characteristics of chitosan and PE. These results confirmed that chitosan coating enriched with PE can be an improving method to reducing deterioration of refrigerated Nemipterus japonicus fillets.