University of Guilan Aquatic Animals Nutrition 2980-8499 11 3 2025 09 23 Effect of Saccharomyces cerevisiae fermentation product on growth performance, survival and some hemato-immunological indices of Asian seabass (Lates calcarifer) Effect of Saccharomyces cerevisiae fermentation product on growth performance, survival and some hemato-immunological indices of Asian seabass (Lates calcarifer) 63 79 9756 10.22124/janb.2026.31927.1299 FA Marzieh Ghanbarpour Department of Fisheries, Faculty of Nano and Bioscience and Technology, Persian Gulf University, Bushehr, Bushehr, Iran Gholamreza Badzohreh Department of Fisheries, Faculty of Nano and Bio Science and Technology, Persian Gulf University, Bushehr, Iran , 0000-0001-9464-1789 Ebrahim Sotoudeh Department of Fisheries, Faculty of Nano and Bioscience and Technology, Persian Gulf University, Bushehr, Bushehr, Iran Vahid Morshedi Department of Fisheries and Biology, Persian Gulf Research Institute, Persian Gulf University, Bushehr, Bushehr, Iran Journal Article 2025 07 23 Introduction: For many years, antibiotics have been extensively applied in aquaculture, serving both to treat bacterial infections and to act as growth promoters. However, using antibiotics can negatively impact the environment and human health alike. For example, antibiotic use may result in the release of resistant bacterial strains into the environment, as well as the accumulation of drug residues in fish tissues. The EU has currently banned the use of antibiotics in animal nutrition. Consequently, efforts have been made to find an effective substitute for antibiotics in aquafeed. As eco-friendly alternatives to antibiotic reliance, various additives such as probiotics and postbiotics have been used to improve resistance to diseases in aquatic animals. Among different types of probiotic strains, Saccharomyces cerevisiae (yeast) and yeast fermentation products have been widely used in aquaculture since they enhance nonspecific immunity. Yeast fermentation products, as a product separated from inner yeast cells, could be a functional source of nutrients. S. cerevisiae fermentation product is a new fermented product. This product comprises a rich source of nutrients that can enhance the immunity and growth of fish. Materials and methods: In this experiment, the effects of various levels of S. cerevisiae fermentation product were investigated on the growth performance, survival, and some hematological and immunological responses in juvenile Asian seabass (Lates calcarifer). First, 240 healthy fish with an average body weight of 9.08 ± 0.41 g were randomly distributed to 12 polyethylene tanks with a capacity of 300 L and a density of 20 fish per tank. The fish were divided into four experimental groups in three replications and were fed four diets as follows: control (without adding S. cerevisiae fermentation product), FP1: 0.5%, FP2: 1%, and FP3: 2% S. cerevisiae fermentation product. The fish were fed three times a day until satiation for 8 weeks. At the end, fish were anesthetized for biometric measurements, and growth indices including weight gain percentage (WG), specific growth rate (SGR), protein efficiency ratio (PER), and feed conversion ratio (FCR) were calculated. Hemato-immunological parameters were assessed by collecting blood samples from the treatment and control groups at the end of the experiment. The data analysis in this study was performed using SPSS software version 21. Data were presented as the mean of 3 replicates ± standard deviation using the Duncan post-hoc test to compare means of each treatment. Results and Discussion: The results indicated that adding S. cerevisiae fermentation product in the diet significantly enhanced the growth performance of juvenile Asian seabass. In this study, WG, PER, SGR in FP1, FP2 and FP3 were significantly higher than in control. In contrast, the lowest FCR values of 1, 1.05, and 1.09 were recorded in FP3, FP2, and FP1, respectively, indicating a positive effect of these products on improving FCR. In the present study, growth indices showed a direct correlation with the level of added yeast, and all diets containing yeast resulted in increased growth indices, which could be attributed to enhance nutrient absorption. Bioactive compounds such as nucleotides, mannan oligosaccharides, and amino acids present in the fermentation products can enhance the palatability and food consumption in fish. The present results showed that hematological indices had no significant differences between the treatments and control group (P>0.05). Hematological alterations in fish may be different and depend on fish species, yeast types, experimental conditions, yeast concentrations, and the duration of trials. In the present study, the level of neutrophils in diets containing yeast was significantly higher than in the control group. The number of neutrophils in the treatment FP3 showed significant differences compared to the control group (P<0.05). Immunological assessments demonstrated significant increases in lysozyme activity, total protein, immunoglobulin levels, and albumin in the serum of Asian seabass fed with S. cerevisiae fermentation product (P<0.05). In this study, the increase in neutrophils in the blood may be responsible for the elevated lysozyme level in Asian seabass. Compounds such as beta-glucans and mannan oligosaccharides in fermented products can enhance the innate immune system in fish, resulting in increased levels of immune-active proteins Conclusion: The results of the present study showed that the growth performance of juvenile Asian seabass fed with diets containing different levels of S. cerevisiae improved. Additionally, the innate immune responses and antioxidant capacity of Asian seabass improved in this study. However, no significant changes were observed in the blood parameters. The findings of this study suggest that using 1-2% S. cerevisiae fermentation product in diets could improve the growth and immunity of juvenile Asian seabass. Introduction: For many years, antibiotics have been extensively applied in aquaculture, serving both to treat bacterial infections and to act as growth promoters. However, using antibiotics can negatively impact the environment and human health alike. For example, antibiotic use may result in the release of resistant bacterial strains into the environment, as well as the accumulation of drug residues in fish tissues. The EU has currently banned the use of antibiotics in animal nutrition. Consequently, efforts have been made to find an effective substitute for antibiotics in aquafeed. As eco-friendly alternatives to antibiotic reliance, various additives such as probiotics and postbiotics have been used to improve resistance to diseases in aquatic animals. Among different types of probiotic strains, Saccharomyces cerevisiae (yeast) and yeast fermentation products have been widely used in aquaculture since they enhance nonspecific immunity. Yeast fermentation products, as a product separated from inner yeast cells, could be a functional source of nutrients. S. cerevisiae fermentation product is a new fermented product. This product comprises a rich source of nutrients that can enhance the immunity and growth of fish. Materials and methods: In this experiment, the effects of various levels of S. cerevisiae fermentation product were investigated on the growth performance, survival, and some hematological and immunological responses in juvenile Asian seabass (Lates calcarifer). First, 240 healthy fish with an average body weight of 9.08 ± 0.41 g were randomly distributed to 12 polyethylene tanks with a capacity of 300 L and a density of 20 fish per tank. The fish were divided into four experimental groups in three replications and were fed four diets as follows: control (without adding S. cerevisiae fermentation product), FP1: 0.5%, FP2: 1%, and FP3: 2% S. cerevisiae fermentation product. The fish were fed three times a day until satiation for 8 weeks. At the end, fish were anesthetized for biometric measurements, and growth indices including weight gain percentage (WG), specific growth rate (SGR), protein efficiency ratio (PER), and feed conversion ratio (FCR) were calculated. Hemato-immunological parameters were assessed by collecting blood samples from the treatment and control groups at the end of the experiment. The data analysis in this study was performed using SPSS software version 21. Data were presented as the mean of 3 replicates ± standard deviation using the Duncan post-hoc test to compare means of each treatment. Results and Discussion: The results indicated that adding S. cerevisiae fermentation product in the diet significantly enhanced the growth performance of juvenile Asian seabass. In this study, WG, PER, SGR in FP1, FP2 and FP3 were significantly higher than in control. In contrast, the lowest FCR values of 1, 1.05, and 1.09 were recorded in FP3, FP2, and FP1, respectively, indicating a positive effect of these products on improving FCR. In the present study, growth indices showed a direct correlation with the level of added yeast, and all diets containing yeast resulted in increased growth indices, which could be attributed to enhance nutrient absorption. Bioactive compounds such as nucleotides, mannan oligosaccharides, and amino acids present in the fermentation products can enhance the palatability and food consumption in fish. The present results showed that hematological indices had no significant differences between the treatments and control group (P>0.05). Hematological alterations in fish may be different and depend on fish species, yeast types, experimental conditions, yeast concentrations, and the duration of trials. In the present study, the level of neutrophils in diets containing yeast was significantly higher than in the control group. The number of neutrophils in the treatment FP3 showed significant differences compared to the control group (P<0.05). Immunological assessments demonstrated significant increases in lysozyme activity, total protein, immunoglobulin levels, and albumin in the serum of Asian seabass fed with S. cerevisiae fermentation product (P<0.05). In this study, the increase in neutrophils in the blood may be responsible for the elevated lysozyme level in Asian seabass. Compounds such as beta-glucans and mannan oligosaccharides in fermented products can enhance the innate immune system in fish, resulting in increased levels of immune-active proteins Conclusion: The results of the present study showed that the growth performance of juvenile Asian seabass fed with diets containing different levels of S. cerevisiae improved. Additionally, the innate immune responses and antioxidant capacity of Asian seabass improved in this study. However, no significant changes were observed in the blood parameters. The findings of this study suggest that using 1-2% S. cerevisiae fermentation product in diets could improve the growth and immunity of juvenile Asian seabass.

https://janb.guilan.ac.ir/article_9756_fbeebfc1031a96ef6f09a2fd2a2e4eae.pdf