On October 21, at the VNUHCM-University of Science (HCMUS), Researcher Lê Hồng Linh successfully defended a doctoral thesis titled “Study on the Preparation and Testing of a Biological Product Using Yeast Cell Surface Technology (Saccharomyces cerevisiae) for the Prevention of White Spot Syndrome Virus (WSSV) in Whiteleg Shrimp (Litopenaeus vannamei)”, under the supervision of Prof. Đặng Thị Phương Thảo.

The research demonstrated a significant biological effect of Saccharomyces cerevisiae W303::vp28 extract in stimulating immune responses and enhancing resistance against white spot disease in whiteleg shrimp. Supplementation of 10 g yeast extract per kilogram of feed resulted in a protection rate against WSSV of 87.19 ± 2.15% after 14 days. Based on these findings, the researcher developed an optimized formula combining 50% yeast extract containing VP28 and 50% beneficial microorganisms (density 10⁹ cfu/g). The optimal application method was determined as a daily feed supplement at 10 g of biological product per kilogram of feed, which improved both shrimp growth and disease resistance.

Laboratory trials confirmed that the completed formulation achieved a protection rate of 77.8 ± 1.9% against WSSV and enhanced shrimp immunity, with enzyme activity levels of SOP reaching 61 ± 1 and PO reaching 2.2 ± 0.1—markedly higher than treatments using only probiotic supplements (SOP: 34 ± 1.2; PO: 1.5 ± 0.1) or industrial feed alone (SOP: 25 ± 1; PO: 1.1 ± 0.1).

The most significant impact of the study was demonstrated through field trials at commercial shrimp ponds in Binh Dinh Province. The product exhibited a dual effect: boosting shrimp immune system activity throughout the cultivation period and improving pond water quality by effectively controlling H₂S gas, reducing NH₃ and COD concentrations, and inhibiting Vibrio spp. proliferation.

After 90 days of cultivation, shrimp raised in ponds treated with the new formulation achieved an average weight of 16.02 ± 0.37 g (an 18.2% increase) and a length of 12.54 ± 0.29 cm (a 6.6% increase) compared to the control group. Economically, the trial pond yielded a profit of VND 129.7 million, approximately 1.6 times higher than ponds using existing commercial products. The yeast extract–probiotic formulation demonstrated strong potential for practical application in shrimp aquaculture, enhancing immune function, reducing disease incidence, and improving profitability for farmers.