Enhancement of superoxide dismutase and catalase activity in juvenile brown shrimp, Farfantepenaeus californiensis (Holmes, 1900), fed β 1.3 glucan vitamin E, and β caroteneand infected with white spot syndrome virus

Abstract

ABSTRACT. Infectious pancreatic necrosis virus (IPNV) is the causal agent of a highly prevalent disease that affects salmonid fish, mostly during their fresh water life period. Like many other viruses, IPNV produces highly heterogeneous populations. Therefore, diagnostic methods need to be checked constantly so that no variants of the virus escape detection. The IPNV genome is composed of two double-stranded RNA segments: A and B, polymerase chain reaction (PCR) methods normally use segment A as a target. In order to develop an optimized protocol to diagnose IPNV, we present a real-time RT-PCR (reverse transcription) technique, using primers designed to recognize segment B of the virus. To validate the ubiquity of the primers used, the IPNV isolates tested were sequenced and compared with previously published cladograms, which include a wide spectrum of genogroups. These primers made it possible to detect viral isolates belonging to genogroups 1 and 5, which were obtained from different locations linked to fish farming. As expected, we were able to detect the virus from distant Aquabirnavirus genogroups. Keywords: infectious pancreatic necrosis virus (IPNV), real-time RT-PCR assay, VP1 gene, phylogenetic tree.Detección y cuantificación de cepas chilenas del virus de la necrosis pancreática infecciosa por medio de la técnica de RT-PCR en tiempo real usando el segmento B como objetivo RESUMEN. El virus de la necrosis pancreática infecciosa (IPNV) es el agente causal de una enfermedad altamente prevalente que afecta a peces salmónidos, principalmente durante su período de vida en agua dulce. IPNV, así como muchos otros virus, produce poblaciones altamente heterogéneas. Por lo tanto los métodos de diagnóstico necesitan ser constantemente revisados para evitar que ciertas variantes del virus escapen de la detección. El genoma del IPNV está compuesto por dos segmentos de ARN de doble hebra, A y B, los métodos de PCR (reacción en cadena de la polimerasa) normalmente usan el fragmento A como blanco. Con el propósito de generar un protocolo optimizado para el diagnóstico del IPNV, se presenta una técnica de RT-PCR (transcripción reversa-) en tiempo real, usando partidores diseñados para reconocer el segmento B del virus. Para validar la universalidad de los partidores utilizados, los aislados del IPNV probados fueron secuenciados y comparados con cladogramas previamente publicados, los cuales incluyen un amplio rango de genogrupos. Con estos partidores fue posible detectar aislados virales pertenecientes a los genogrupos 1 y 5, provenientes de distintas localidades relacionadas con el cultivo de peces. Como se esperaba, se logró detectar virus pertenecientes a genogrupos distantes de Aquabirnavirus. Palabras clave: virus de la necrosis pancreática infecciosa (IPNV), ensayo en tiempo real RT-PCR, gen VP1, árbol filogenético.

Effects of β-glucan on ROS production and energy metabolism in yellow croaker (Pseudosciaena crocea) under acute hypoxic stress

“…Although hypoxic stress with b-glucan had similar effects on activities of aerobic metabolic enzymes compared with hypoxic stress alone, b-glucan responsible for energy production from glycolysis remained the high levels for up to 48 h of hypoxia exposure in comparison with hypoxic stress alone. A more plausible explanation for the fact that hypoxic stress with b-glucan reduced ROS formation compared to hypoxic stress alone may be that b-glucan confers a protective role against hypoxia-induced damage probably by means of a yet unknown anaerobic energyproducing system, besides its function in enhancing the effects of oxidative stress (Kim et al 2009;Pacheco et al 2011). Similar results have previously been observed in trained rats fed b-glucan (Xu et al 2013).…”

Effect of dietary supplementation of periphyton on growth, immune response and metabolic enzyme activities inPenaeus monodon

“…This agrees with the earlier reports where higher immune response in terms of SOD and catalase activities were recorded in shrimps fed β‐glucan, carotene (Pacheco et al . ), microalgae (Madhumathi & Rengasamy ) and macro algal supplements (Felix & Murugan ). These suggest that dietary supplementation of periphyton can elicit the anti‐oxidative enzymes in shrimp and enhance the defence potential against oxidative stress.…”

“…Immunostimulants are used in shrimp culture to improve the shrimp health through the induction of non-specific immune system (Sakai 1999). Widely used dietary immunostimulants are b-glucan and yeast (Pacheco, Ascencio, Zarain, Gomez & Campa 2011), microalgae and carotenoids (Supamattaya, Kiriratnikom, Boonyaratpalin & Borowitzka 2005) and probiotics (Li, Tan & Mai 2009). Dietary immunostimulants affect the physiological status of aquatic organisms (Akhtar, Pal, Sahu, Alexander, Gupta, Choudhary, Jha & Rajan 2010).…”

Comparison of mortality and viral load in rainbow trout (Oncorhynchus mykiss) infected with infectious pancreatic necrosis virus (IPNV) genogroups 1 and 5

“…Chile is currently the largest producer of anadromous rainbow trout grown in marine cages (FAO, 2019), and it was in this species that IPNV was isolated for the first time in the country (McAllister & Reyes, 1984). The isolate corresponded to serotype VR-299 or 1A (Espinoza, Farías, Soler, & Kuznar, 1985), and it was later classified in genogroup 1 (Eissler, Pavlov, Conejeros, Espinoza, & Kuznar, 2011), according to the genetic classification proposed by Blake et al (2001). During the late nineties, IPN disease was confirmed in Atlantic salmon farms, and since then, the virus has spread through the country's different farming areas.…”

“…Samples from mortality and survivor fish were tested to confirm the presence of IPNV and to estimate viral load. A RT-qPCR assay for the VP1 region of the virus (Eissler et al, 2011) was used to confirm the presence of the virus in both mortality and survivor fish samples, while an indirect fluorescent antibody test (IFAT) targeting the VP2 protein of the virus (Espinoza & Kuznar, 2002) was used only on samples from mortalities. For the latter, homogenization was done in 1 ml of L-15 medium using bead beating in the Minlys (Bertin) homogenizer.…”