Laboratory of Aquatic Animal Health and Therapeutics, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, 43400 UPM, Malaysia.
Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor, 43400 UPM, Malaysia.
Arch Microbiol. 2024 Oct 23;206(11):444. doi: 10.1007/s00203-024-04166-2.
Feed-based bivalent vaccine (FBBV) containing killed whole organism (KWO) of Streptococcus agalactiae and Aeromonas hydrophila with 10% palm oil was previously proved to improve red hybrid tilapia's (Oreochromis sp.) immunity against streptococcosis and Aeromonas infections. This study characterized the FBBV's stability following the preparatory process and storage. The FBBV was prepared, and the KWO's stability was determined microscopically and molecularly. The efficacy of FBBV stored at room temperature (25 ± 2 °C) for 0, 30 and 60 days was investigated in red hybrid tilapia. The results indicated the addition of palm oil was not affecting the KWO's structure and helping in the FBBV's pelletization. In 1 g of FBBV contained 1.5 × 10 CFU/g of S. agalactiae and 4.9 × 10 CFU/g of A. hydrophila, respectively, even after 60 days of storage at room temperature. The KWO's structure in FBBV was not affected following in vitro acidic tolerance analysis, as noted from light and electron microscopies. The FBBV's carbohydrate, energy, moisture, total protein and total ash contents remained stable at 95% after 60 days of storage at room temperature, while the KWO's concentration was slightly reduced to 83.3% for S. agalactiae (1.25 × 10 CFU/g) and 80.6% for A. hydrophila (3.85 × 10 CFU/g), respectively. Fish vaccinated with FBBV that was stored for 0, 30 and 60 days did not show any significant differences (p ≥ 0.05) in the relative percent survival when challenged with pathogenic Streptococcus spp. and Aeromonas spp. These findings suggested that the FBBV is a stable vaccine, which underscores its potential application as aquatic vaccines in aquaculture.
基于饲料的双价疫苗（FBBV）含有已杀死的蓝氏贾第鞭毛虫和豚鼠气单胞菌的全菌体（KWO），并用 10%棕榈油佐剂，此前已被证明可提高红杂交罗非鱼（Oreochromis sp.）对链球菌病和豚鼠气单胞菌感染的免疫力。本研究对 FBBV 经过制备过程和储存后的稳定性进行了特征描述。制备了 FBBV，并通过显微镜和分子学方法确定了 KWO 的稳定性。在红杂交罗非鱼中，研究了在室温（25 ± 2°C）下储存 0、30 和 60 天的 FBBV 的功效。结果表明，添加棕榈油不会影响 KWO 的结构，并有助于 FBBV 的颗粒化。在 1g 的 FBBV 中，分别含有 1.5×10 CFU/g 的链球菌和 4.9×10 CFU/g 的豚鼠气单胞菌，即使在室温下储存 60 天后也是如此。通过体外耐酸性分析，从光镜和电子显微镜观察到，FBBV 中的 KWO 结构没有受到影响。在室温下储存 60 天后，FBBV 的碳水化合物、能量、水分、总蛋白和总灰分含量保持稳定在 95%，而链球菌的 KWO 浓度略有下降至 83.3%（1.25×10 CFU/g），豚鼠气单胞菌的 KWO 浓度略有下降至 80.6%（3.85×10 CFU/g）。用储存 0、30 和 60 天的 FBBV 接种的鱼在受到致病性链球菌和豚鼠气单胞菌的挑战时，相对存活率没有任何显著差异（p≥0.05）。这些发现表明，FBBV 是一种稳定的疫苗，这突出了其作为水产养殖中水生疫苗的潜在应用。
