ESPOL Polytechnic University, Escuela Superior Politécnica del Litoral, ESPOL, Centro Nacional de Investigaciones Marinas (CENAIM), Campus Gustavo Galindo Km. 30.5 Vía Perimetral, P.O. Box 09-01-5863, Guayaquil, Ecuador; Facultad de Ingeniería Marítima y Ciencias del Mar, Escuela Superior Politécnica del Litoral, ESPOL, Guayaquil, Ecuador.
ESPOL Polytechnic University, Escuela Superior Politécnica del Litoral, ESPOL, Centro Nacional de Investigaciones Marinas (CENAIM), Campus Gustavo Galindo Km. 30.5 Vía Perimetral, P.O. Box 09-01-5863, Guayaquil, Ecuador; Programa de Doctorado en Biotecnología, Pontificia Universidad Católica de Valparaíso. Valparaíso, Chile. Universidad Técnico Federico Santa María, Valparaíso, Chile.
Fish Shellfish Immunol. 2024 Nov;154:109938. doi: 10.1016/j.fsi.2024.109938. Epub 2024 Oct 5.
Penaeus vannamei is the main species of shrimp farmed worldwide, and for Ecuador it is the first non-oil economic sector. However, various pathogens, including white spot syndrome virus (WSSV), threaten the sustainability of shrimp farming. P. vannamei larvae are susceptible to WSSV infection via vertical or horizontal transmission. To decrease the incidence of WSSV in PLs, a bioassay was performed by exposing P. vannamei shrimp (PL25), which were negative for WSSV and white spot disease (WSD), to two protective factors, water temperature (T = 24 °C and T = 31 °C), and immunestimulation using β-1,3-glucans (BG) (with and without BG added to the food), using a crossed two-factor design, for 20 days. The incidence of WSSV and WSD was modeled using generalized linear model (GLM). The strength of the association between the response and explanatory variables was estimated using the odds ratio [Exp (Beta)] and interpreted as the level of risk for the incidence of WSSV or WSD in one of the categories compared to the baseline category in the GLM. Odds ratios were considered significant if their 95 % confidence interval did not include the value 1. The results showed that BG had a significant negative effect on the number of WSSV-positive animals. In addition, a lower probability of WSSV infection was determined by combining 31 °C and BG. In this treatment, the WSD injuries were almost undetectable. Most larvae shrimps affected by WSD exhibited injuries to the antennal gland and connective tissue. In situ hybridization analysis revealed that 29 % of shrimp, initially negative by histology, were positive for WSSV. The virus was detected mainly in the nervous tissue of the head, epithelium, connective tissue of the head appendages, and the oral region surrounding the integumental glands. Apoptosis analysis showed a weak signal in nerve tissue but was more intense in epithelial cells of the head appendages, in association with cuticular damage. According to the findings, WSSV could disseminate among shrimp populations by infecting them through the TG and epithelium of the head appendage, followed by connective tissue and nervous tissue. However, applying BG at 31 °C may serve as a protective measure to reduce WSD injuries and restrict WSSV dissemination.
凡纳滨对虾是世界范围内主要的养殖虾种，对厄瓜多尔而言，它是第一大非石油经济部门。然而，包括白斑综合征病毒（WSSV）在内的各种病原体威胁着虾养殖业的可持续性。凡纳滨对虾幼虫可通过垂直或水平传播感染 WSSV。为降低 PL 中 WSSV 的发病率，通过生物测定，将未感染 WSSV 和白斑病（WSD）的凡纳滨对虾（PL25）暴露于两种保护因素下，即水温（T=24°C 和 T=31°C）和使用 β-1,3-葡聚糖（BG）进行免疫刺激（BG 添加或不添加到食物中），采用交叉两因素设计，进行 20 天。使用广义线性模型（GLM）对 WSSV 和 WSD 的发病率进行建模。使用优势比[Exp（Beta）]估计响应和解释变量之间的关联强度，并将其解释为 GLM 中与基线类别相比，WSSV 或 WSD 发病率的风险水平。如果优势比的 95%置信区间不包括 1，则认为其具有统计学意义。结果表明，BG 对 WSSV 阳性动物的数量有显著的负影响。此外，31°C 和 BG 的组合降低了 WSSV 感染的可能性。在这种处理下，WSD 损伤几乎无法检测到。受 WSD 影响的大多数幼虾表现出触角腺和结缔组织损伤。原位杂交分析显示，29%的最初组织学阴性的虾对 WSSV 呈阳性。该病毒主要存在于头部的神经组织、上皮组织、头部附属物的结缔组织以及围绕表皮腺的口腔区域。凋亡分析显示神经组织中信号较弱，但头部附属物的上皮细胞中信号较强，与角质层损伤有关。根据研究结果，WSSV 可通过感染 TG 和头部附属物的上皮组织在虾群中传播，然后传播到结缔组织和神经组织。然而，在 31°C 下应用 BG 可能是一种减轻 WSD 损伤和限制 WSSV 传播的保护措施。
