Health Benefits of Verjuice on Immune System and Gene Activity in Young Fish

Jenn Hoskins
22nd June, 2024

Health Benefits of Verjuice on Immune System and Gene Activity in Young Fish

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Islamic Azad University found that adding verjuice (VJ) to rainbow trout diets significantly improved their immune and blood health
  • The group receiving 9 mL/kg of VJ showed notable increases in white blood cells, neutrophils, and monocytes
  • VJ supplementation enhanced skin mucus immunity, boosting enzymes and proteins that fight infections
  • The study revealed that VJ-treated fish had higher mRNA levels of key immune markers and better antibacterial activity against Aeromonas hydrophila
The development of green aquaculture practices has led to the supplementation of fish diets with natural immunostimulants such as organic acids. This study, conducted by researchers at Islamic Azad University, aimed to assess the dietary effects of verjuice (VJ; unfermented unripe grapes; Vitis vinifera) on hematological parameters, skin mucosal immunity, transcriptional immune responses, and antibacterial serum activity against Aeromonas hydrophila in rainbow trout[1]. The fish were randomly distributed into 15 tanks and fed ad-libitum thrice daily with diets containing different levels of VJ for 56 days. The results showed that immuno-hematological parameters, including total white blood cells, neutrophils, and monocytes, were significantly improved in the groups receiving VJ (P ˂ 0.05). Specifically, the VJ-9 group (9 mL/kg) demonstrated notable enhancements in serum immunological parameters. Skin mucus immunology exhibited significant increases in various parameters such as alkaline phosphatase, lysozyme activity, alkaline protease, total protein, total immunoglobulin, and esterase levels in the VJ-9 group compared to the control group (P < 0.05). Additionally, the mRNA expression of interleukin-1β, interleukin-6, interleukin-8, and immunoglobulin M were significantly higher in the VJ-9 group (P ˂ 0.05). The antibacterial evaluation indicated that A. hydrophila growth was significantly inhibited in the serum samples from the VJ-3 to VJ-9 groups after the 56th day and in all VJ-treated groups after the 70th day (P ˂ 0.05). The study concluded that dietary VJ is a novel immunostimulant, with the optimal dietary supplementation level being 6.65-7.46 mL/kg, effectively improving immune responses in rainbow trout. This study ties together previous findings in several ways. For instance, earlier research demonstrated the benefits of dietary lactic acid (LA) supplementation on rainbow trout, showing improvements in hematological characteristics, humoral antioxidant and immunological factors, and intestinal microflora[2]. Similarly, the current study found that VJ supplementation enhances immune responses and hematological parameters in rainbow trout, aligning with the beneficial effects observed with LA. Moreover, the study's findings on the enhanced skin mucosal immunity with VJ supplementation can be compared to the effects of propolis on rainbow trout, where certain concentrations of propolis led to increased leukocyte counts and changes in biochemical parameters[3]. Both studies highlight the potential of natural substances to modulate immune responses and improve fish health. Additionally, the antibacterial properties of VJ against A. hydrophila observed in this study are consistent with the findings from a study on Pacific white shrimp, where a blend of organic acids and essential oils improved disease resistance and immune responses[4]. This suggests that natural dietary supplements can play a crucial role in enhancing the overall health and disease resistance of aquaculture species. In conclusion, the study conducted by Islamic Azad University provides compelling evidence that dietary verjuice is an effective immunostimulant for rainbow trout, enhancing various immunological and hematological parameters, and offering protection against bacterial infections. These findings, in conjunction with previous studies, underscore the potential of using natural substances to promote sustainable and healthy aquaculture practices.

NutritionGeneticsAnimal Science

References

Main Study

1) Immunostimulatory effects of dietary verjuice (Vitis vinifera) on immune response and transcription of immune-related genes in juvenile rainbow trout (Oncorhynchus mykiss).

Published 19th June, 2024

https://doi.org/10.1016/j.fsi.2024.109714

Related Studies

2) Modulation of humoral immunological and antioxidant responses and gut bacterial community and gene expression in rainbow trout, Oncorhynchus mykiss, by dietary lactic acid supplementation.

https://doi.org/10.1016/j.fsi.2022.04.038

3) Effects of various propolis concentrations on biochemical and hematological parameters of rainbow trout (Oncorhynchus mykiss).

https://doi.org/10.1016/j.ecoenv.2009.04.011

4) Effects of organic acids and essential oils blend on growth, gut microbiota, immune response and disease resistance of Pacific white shrimp (Litopenaeus vannamei) against Vibrio parahaemolyticus.

https://doi.org/10.1016/j.fsi.2017.09.007


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