VNF BULLETIN 0??1??3?? – Nano Chitosan: The Key to Growth and Immune Enhancement in Nile Tilapia
In mid-February 2023, in Egypt, more than 25,000 juvenile Nile tilapia reared in a 4,000m2 earthen pond unexpectedly died in mass following a period of heavy rainfall. Water sample analysis revealed that the main cause was septicemia, with Pseudomonas fluorescens (P. fluorescens) identified as one of the two main pathogenic bacteria responsible for the outbreak. This bacterium is capable of causing mortality rates of up to 53.3% when fish are exposed (Hossam et al., 2015).?
In 2023, also in Egypt, a research group investigated the effects of Nano Chitosan (CNPs) and Silver Nanoparticles (AgNPs) on fish growth, immunity, and survival rates when challenged with Pseudomonas fluorescens. The study found that supplementing CNPs (2g/kg feed) resulted in a weight gain of 72g and reduced the feed conversion ratio (FCR) from 1.71 (control) to 0.94 over 60 days. After 10 days of bacterial exposure, the survival rate increased from 60% (control) to 90% with CNPs supplementation. AgNPs supplementation (1mg/kg feed) also showed promising results. These findings highlight the potential of CNPs and AgNPs as effective solutions for enhancing disease resistance in aquaculture.?
Infection with P.fluorescens leads to ulcers and necrosis in various freshwater fish species, including pangasius, basa, and catfish. However, treatment options are limited due to concerns about antibiotic residues. Environmentally friendly alternatives, CNPs and AgNPs have gained attention for their ability to boost immunity and enhance digestion, offering a sustainable approach to controlling P. fluorescens infections in fish.
EXPERIMENTAL INFORMATION?
(*) At the end of the experiment, 10 fish from each group were challenged by intraperitoneal injection with P.fluorescens. The survival rate of the fish was monitored over the following 10 days.?
RESULTS?
?? Improved weight gain and feed conversion ratio (FCR): CNPs significantly enhanced weight gain (72g) compared to AgNPs (37.67g) and the control group (21g). Additionally, FCR was markedly improved, reaching 0.94 in the CNPs group—nearly 45% lower than the control group's FCR of 1.71.??
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? Enhanced health indicators: In the CNPs group, the antioxidant enzyme superoxide dismutase (SOD) increased by 33%, while the number of immune white blood cells in the blood rose by 56%. Additionally, markers indicating liver and kidney damage—Alanine Aminotransferase (ALT) and Urea—decreased by 26% and 11%, respectively, compared to the control group.?
? Improved intestinal health post-challenge: Intestinal villi proliferation was observed, with a notable increase in villi height in the CNPs group compared to the control. This improvement enhances the surface area for nutrient absorption, supporting better recovery and overall gut health.?
? Increased survival rate post-challenge: The survival rate of Nile tilapia after infection with P.fluorescens improved significantly, reaching 90% in the CNPs group and 75% in the AgNPs group, compared to 60% in the control group.??
The study highlights the effectiveness of nano chitosan (CNPs) and silver nanoparticles (AgNPs) in enhancing growth and immunity in Nile tilapia, particularly in increasing survival rates when infected with P.fluorescens to 75–90%, compared to 60% in the control group. In the context of sustainable aquaculture development in Vietnam, the application of CNPs emerges as a promising solution to reduce antibiotic usage and enhance production efficiency.?
Vietnam Food Joint Stock Company (VNF) offers a wide range of Chitosan-based products, including KITO–SIL, a new product combining Chitosan and Silver Nanoparticles, specifically designed to enhance aquatic animal health. If you are interested in this product, please feel free to contact the VNF team.?
Source: Salah M. Aly, 2023, The antibacterial activity and immunomodulatory effect of naturallysynthesized chitosan and silver nanoparticles against Pseudomonasfluorescence infection in Nile tilapia (Oreochromis niloticus): An in vivo study, Link?