Hemograma e sobrevivência de camarões marinhos após silenciamento do WSSV por RNA de interferência

Abstract

O objetivo deste trabalho foi avaliar a proteção antiviral específica via RNA de interferência (RNAi) contra o vírus da síndrome da mancha-branca (WSSV), em camarões marinhos (Litopenaeus vannamei). Os camarões foram injetados com uma sequência dsRNA específica (vp28 do envelope viral), seguida por desafio com WSSV após 48 horas. Avaliaram-se o hemograma às 0, 3, 6, 24, 48 e 72 horas após o desafio, e a taxa de mortalidade durante 30 dias. Nos animais tratados com dsRNA vp28, a infecção viral foi limitada, e a sobrevivência (73%) e a "clearance" viral (80%) foram maiores do que nos camarões infectados, não tratados, que apresentaram 100% de mortalidade em cinco dias. Nos camarões tratados com dsRNA, o hemograma diminuiu até 6 horas após o desafio, seguido por aumento, tendo atingido o nível normal em 72 horas. O tratamento com dsRNA vp28 limita a infecção nos camarões por WSSV, restaura as suas condições imunológicas e promove "clearance" viral na maioria dos sobreviventes. Esses resultados são indicativos de que dsRNA vp28 pode servir como ferramenta molecular para combater o WSSV e que o RNAi representa abordagem promissora para controlar doenças virais em camarões cultivados.

Effects of adding rotifers on the water quality, plankton composition and growth of Pacific white shrimp,Litopenaeus vannameijuvenile, when cultured with biofloc technology

“…At the end of shrimp culture and after the final salinity stress test, a haemolymph sample was taken according to Guertler et al (2013) with a 1‐ml syringe containing 200 μL of precooled anticoagulant modified Alsever solution (MAS) (336 mmol/L NaCl, 115 mmol/L glucose, 27 mmol/L sodium citrate, 9 mmol/L EDTA, pH 7.2) at a proportion of 1:2 (v:v). For total haemocyte counting (THC), triplicates of 100 μL of diluted haemolymph were counted for the number of haemocytes using a haemocytometer under a light microscope.…”

Effects of addition ofNaviculasp. (diatom) in different densities to postlarvae of shrimpLitopenaeus vannameireared in a BFT system: Growth, survival, productivity and fatty acid profile

“…The measurement of presumptive analysis (Morales‐Covarrubias, ) and total haemocyte count (THC) (Guertler et al, ) were performed for 40 shrimp at the end of the rearing period (day 42). To measure presumptive analysis, the following scores were considered: degree of intestinal repletion—(0) empty; (1) slightly full; (2) moderately full; and (3) full; hepatopancreas–Tubules: (0) shows no signs of infection or deformation; (1) low presence of tubular deformation (1–5/field/organism); (2) moderate presence of tubular deformation (6–10/field/organism), atrophy, melanization and tubular necrosis; and (3) high presence of tubular deformation (11–16/field/organism), with moderate to severe lesions, with melanization, necrosis and tubular atrophy; epicomensals in the gills lamellae—(0) does not present lesions caused by epicomensals; (1) low presence of protozoa (1–5/lamella/organism) and lesions caused by epicomensals; (2) moderate presence of protozoa (6–10/lamella/organism) and increased epicomensal lesions (melanization and formation of haemocytic nodules); and (3) high presence of protozoa (10–15/lamella/organism), moderate to severe lesions caused by epicomensals (multifocal melanized areas and formation of haemocytic nodules).…”

“…The measurement of presumptive analysis (Morales-Covarrubias, 2010) and total haemocyte count (THC) (Guertler et al, 2013) were performed for 40 shrimp at the end of the rearing period (day 42).…”

Effect of the transference of animals to different culture systems on growth performance and response to infection by white spot syndrome virus in the marine shrimp Litopenaeus vannamei (Boone, 1931) in the nursery phase

“…The haemolymph (12 shrimp per treatment) was collected for the blood analysis before and after the viral challenge following the protocol described by Guertler et al (2013). For such, the haemolymph (100 μl) was collected from the haemocoel located in the ventral region of the surviving animals with the aid of a syringe (1 ml) containing anticoagulant (modified Alsever's solution [MAS: 336 mmol L −1 of NaCl, 115 mmol L −1 of glucose, and 27 mmol L −1 of sodium citrate, and 9 mmol L −1 of EDTA, pH 7.2]) at a proportion of 1:2 (v:v).…”