Resistance to Acute Hepatopancreatic Necrosis Disease of Egg Yolk Antibodies

Application of egg yolk antibodies IgYB to enhance immunity, against AHPND acute hepatopancreatic necrosis disease in white shrimp.

Currently, there are many solutions to help strengthen the immune system of shrimp towards biosecurity, not only with simple practices but also with high efficiency. Recent research by the author Tran Thi Tuyet Hoa and colleagues (Department of Fisheries, Can Tho University) showed that supplementary food IgYB improves survival and enhances the immunity in vannamei when challenged. with V. parahaemolyticus . 

Immunoglobulins (Ig) are antibodies of a glycoprotein nature. Immunoglobulins Y (IgY) are produced from the egg yolks of a hen and differ in protein nature compared to mammalian Ig. To produce specific antibodies, a specific antigen ( Vibrio parahaemolyticus, Vibrio harveyi, Vibrio anguillarum ) is injected into the hens' breast muscle. After the production, the specific antibody will switch to the egg yolk to produce IgY antibodies.

In recent years, egg yolk antibody (IgY) has attracted considerable attention because it has many advantages: it helps the subject object to be resistant to pathogens, is environmentally friendly, stable, Safe, economical and contains high concentrations, with no side effects or harmful residues. Therefore, IgY is successfully used in medical immunology and is applicable for passive immunization in both animals and humans.

Also read: Shrimp Aquaculture and Competitive Exclusion Of Pathogens

Currently, the increase in farming area along with intensive farming leads to widespread epidemic diseases, seriously threatening productivity and  sustainable development of shrimp farming. In which, V. parahaemolyticus is a causative agent of acute hepatopancreatic necrosis  disease (AHPND) causing mortality up to 100% after 20-30 days after stocking. Therefore, the application of egg yolks to resist acute hepatopancreatic necrosis disease of white shrimp is necessary.

The study evaluated the immune parameters and survival rate of shrimp. The experiment includes 4 treatments: negative control; positive control; the IgYA 0.5% treatment and the IgYB 0.5% treatment over a 5 week period. The bacteria were then challenged with V. parahaemolyticus by immersion method with a concentration of 1.6 x 10 7 CFU / mL.

IgYA and IgYB egg yolk antibodies are sprayed over the food pellets at the rate of 0.5%, continue to cover the food pellets with squid oil and stored at 4 ° C.

Also read: Transcriptomic Analysis of Pacific White Shrimp in Response to AHPND

The results of the above experiment showed that adding IgY to the feed has the ability to help shrimp increase resistance to bacteria causing acute hepatopancreatic necrosis disease V. parahaemolyticus , in which shrimp in the treatment treatment supplemented with 0.5 IgYB. % had the lowest mortality during the time of the challenge.

Meanwhile, total blood cells in treatments susceptible to V. parahaemolyticus , NT4 (supplemented with 0.5% IgYB) had the highest values of THC, granulocyte and prophenoloxidase activity, respectively. 1.89x10 4 tb / mm 3 , 1.53x10 4 tb / mm 3 , 0.173x10 4 statistically significant differences (p <0.05) with the remaining treatments.

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The addition of IgY helps to stimulate the immune system specific to the pathogen, so when bacteria enter the shrimp body, it will increase the immune response and the participant (prophenoloxidase, serum lysozyme, ...). In this experiment, the results of analysis of the immune parameters of vannamei shrimp after challenge showed that supplementing with 0.5% IgYB helped increase the immune response of shrimp, through an increase in numbers. amount of blood cells, granulocytes, granulocytes and PO activity thereby increasing disease resistance to V. Parahaemolyticus .

Vannamei shrimp fed with egg yolk antibodies 0.5% IgYB to help vannamei strengthen immunity, increase survival rate when susceptible to V.  parahaemolyticus .

The study of applying Vibrio-resistant egg yolks to white shrimp has opened up a great potential in the way of using biological agents to limit the harmful effects of this dangerous bacteria.

Source: Tepbac.com

Report on  Effects of diets with egg yolk antibodies on the immune response and disease resistance of white leg shrimp (penaeus vannamei) by  Tran Thi Tuyet Hoa, Le Quoc Viet, Tran Thi My Duyen, Tran Nguyen Duy Khoa, Tran Ngoc Hai and Ahn Hyeong Chul.