RESUMO
AIMS: The present study evaluated the effect of four functional diets and a reference diet on the survival and intestinal bacterial community of shrimp Penaeus vannamei infected with acute hepatopancreatic necrosis disease (AHPND). METHODS AND RESULTS: After 42 days of feeding trail, shrimp were inoculated with a Vibrio parahaemolyticus (CIB-0018-3) carrying the plasmid encoding for the PirAB toxins responsible for AHPND. After 120 h postinfection (hpi), shrimp fed with a diet containing 2% of a mix with Curcuma longa and Lepidium meyenii (TuMa) and a diet containing 0.2% of vitamin C (VitC) showed a significantly higher survival (85%) compared to the remaining treatments (50%-55%) (p < 0.05). Infected shrimp fed with TuMa diet, showed a significant reduction of Vibrionales, and VitC diet promoted an increase of Alteromonadales. CONCLUSIONS: Our findings suggest that the TuMa diet conferred protection against AHPND and could be attributed to a combined effect of antibacterial properties against Vibrionales, and promoting a desirable bacterial community in the shrimp intestine, while the VitC diet protection could be attributed to their antioxidant capacity and in a lower proportion to a bacterial modulation in shrimp gut. SIGNIFICANCE AND IMPACT OF THE STUDY: Acute hepatopancreatic necrosis disease is a devastating disease that significantly affects aquaculture production of shrimps. Therefore, the use of functional diets that promote resistance to AHPND represents a valuable tool to reduce the mortality of farmed shrimp.
Assuntos
Microbioma Gastrointestinal , Penaeidae , Vibrio parahaemolyticus , Animais , Dieta/veterinária , Hepatopâncreas/microbiologia , Necrose , Penaeidae/microbiologiaRESUMO
The white spot syndrome virus (WSSV), the most lethal pathogen of shrimp, is a dsDNA virus with approximately a 300,000 base pairs and contains approximately 180-500 predicted open reading frames (ORFs), of which only 6% show homology to any known protein from other viruses or organisms. Although most of its ORFs encode enzymes for nucleotide metabolism, DNA replication, and protein modification, the WSSV uses some of its encoded proteins successfully to take control of the metabolism of the host and avoid immune responses. The contribution of the shrimp innate immune response to prevent viral invasions is recognized but yet not fully understood. Thus, the role of several components of Toll pathway of the shrimp Penaeus vannamei against WSSV has been previously described, and the consequential effects occurring through the cascade remain unknown. In the current study the effects of WSSV over various components of the shrimp Toll pathway were studied. The gene expression of Spätzle, Toll, Tube, Cactus and Dorsal was altered after 6-12â¯h post inoculation. The expression of LvToll3, LvCactus, LvDorsal, decreased ~4.4-, ~3.7- and ~7.3-fold at 48, 24 and 48 hpi, respectively. Furthermore, a remarkable reduction (~18-fold) in the expression of the gene encoding LvCactus in WSSV infected specimens was observed at 6 hpi. This may be a sophisticated strategy exploited by WSSV to evade the Toll-mediated immune action, and to promote its replication, thereby contributing to viral fitness.
Assuntos
Imunidade Inata/genética , Penaeidae/imunologia , Transdução de Sinais/imunologia , Receptores Toll-Like/imunologia , Replicação Viral , Vírus da Síndrome da Mancha Branca 1/fisiologia , Animais , Penaeidae/genética , Penaeidae/virologia , Distribuição Aleatória , Receptores Toll-Like/genéticaRESUMO
The decapod penstyldensovirus (PstDV1) is a widely spread shrimp pathogen that causes high mortalities in the shrimp Penaeus stylirostris, while in P. vannamei, it has been associated with induction of the runt deformity syndrome. Using shrimp post-larvae (PL, stages PL13-PL21) collected from 16 commercial hatcheries from Mexico, and a sensitive PCR protocol for its detection, a survey of the PstDV1 prevalence in larvae was undertaken. A high overall prevalence of PstDV1 (49.5 %) in shrimp PL from the studied hatcheries was found. This study reveals that PstDV1 occurs persistently in PL populations, which may have significant implications for its dispersal.
Assuntos
Densovirinae/isolamento & purificação , Penaeidae , Animais , México , Reação em Cadeia da Polimerase , PrevalênciaRESUMO
The Penaeus stylirostris densovirus (PstDV) (also known as infectious hypodermal and hematopoietic necrosis virus, IHHNV), one of the major shrimp pathogens, has a worldwide distribution in farmed and wild shrimp populations. Outbreaks of IHHNV have been associated with substantial economic losses which are accompanied by a negative social impact. Current diagnostic PCR tests may result in false-positive results as several parts of PstDV genome may be endogenized in the nuclear genome of the shrimp P. stylirostris. A one-step qPCR SYBR-Green based quantitative real-time polymerase chain reaction (qPCR) assay to detect different isolates of the IHHNV in shrimp samples was developed. The detection limit of the assay was 81 viral copies of targeted DNA per reaction. The specificity of the assay was evaluated by melting curve analysis, which showed that the IHHNV product generated a single melt peak at 81.4±0.044°C. The assay was more sensitive than conventional PCR. The standardized PCR was shown to be highly sensible, specific, robust, and reproducible, which makes it an economical and powerful tool for both diagnostic applications and general research of IHHNV.
Assuntos
Densovirus/isolamento & purificação , Penaeidae/virologia , Reação em Cadeia da Polimerase em Tempo Real/métodos , Virologia/métodos , Animais , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , TemperaturaRESUMO
The Penaeus stylirostris densovirus (PstDNV or IHHNV) is the smallest of the known shrimp viruses. It causes severe mortalities in juveniles and sub-adults of the blue shrimp Penaeus stylirostris, while specimens of the white shrimp Penaeus vannamei infected by this virus exhibit reduced growth rates and negative effects on the feed-conversion rate (FCR). To date, no descriptive epidemiological surveys on the prevalence of this virus in shrimp broodstock have been performed. In this study, the prevalence of IHHNV in broodstock of the white shrimp P. vannamei from hatcheries on the northwest of Mexico region was estimated. Prevalence vary across different regions from high (63%) to low (6%) in shrimp broodstock. Several factors, as transport of pathogens by human activities, or the absence or implementation of ineffective biosecurity measures, may explain the observed differences. To the best of our knowledge, the present study is the first to examine the prevalence of IHHNV on broodstock.
Assuntos
Densovirinae/isolamento & purificação , Penaeidae/virologia , Animais , Interações Hospedeiro-Patógeno , México , PrevalênciaRESUMO
The susceptibility of the endemic copepod Calanus pacificus californicus to white spot syndrome virus (WSSV) was established by the temporal analysis of WSSV VP28 transcripts by quantitative real-time PCR (qRT-PCR). The copepods were collected from a shrimp pond located in Bahia de Kino Sonora, Mexico, and challenged per os with WSSV by a virus-phytoplankton adhesion route. Samples were collected at 0, 24, 48 and 84 h postinoculation (hpi). The VP28 transcripts were not detected at early stages (0 and 24 hpi); however, some transcript accumulation was observed at 48 hpi and gradually increased until 84 hpi. Thus, these results clearly show that the copepod C. pacificus californicus is susceptible to WSSV infection and that it may be a potential vector for the dispersal of WSSV. However, further studies are still needed to correlate the epidemiological outbreaks of WSSV with the presence of copepods in shrimp ponds.
Assuntos
Copépodes/virologia , Penaeidae/parasitologia , Penaeidae/virologia , Vírus da Síndrome da Mancha Branca 1/isolamento & purificação , Animais , Vetores de DoençasRESUMO
BACKGROUND: Prevention providers wonder whether benefits achieved in the original, researcher-led, efficacy trials of interventions are replicated when the intervention is delivered in real-world settings by their agency's staff. METHODS: A replication study was conducted at 2 public sexually transmitted disease (STD) clinics (New York City and San Juan, PR). Using a controlled trial design, intervention (VOICES/VOCES) and comparison conditions (regular clinic services) were assigned in alternating 4-week blocks. Trained agency staff delivered the intervention. Effectiveness was assessed for incident STDs, redemption of coupons for condoms at neighborhood location after the visit, and improved knowledge and attitudes about STDs and condoms. RESULTS: A total of 3365 patients were recruited, completed the protocol, and followed through STD surveillance systems for an average of 17 months. Of 397 with an incident infection, 226 (13.4%) were among those enrolled during comparison blocks; 171 were among those in the intervention condition (10.2%). Controlling for site and gender, participants enrolled during intervention blocks were significantly less likely to have an incident STD reported to the surveillance system (hazard ratio, 0.78; 95% confidence interval, 0.64-0.96). Intervention block participants scored higher on scales of STD knowledge (4.89 vs. 3.87, P < 0.001) and condom knowledge, attitude, and efficacy (10.98 vs. 9.16, P < 0.001). More of those exposed to VOICES/VOCES redeemed condoms (P < 0.05). Positive effects were more consistent in New York, which may be related to fidelity of implementation. CONCLUSIONS: A packaged human immunodeficiency virus prevention intervention can be delivered by agencies, with benefits similar to those achieved in the research setting.