Risk factors perceived predictive of ISA spread in Chile: applications to decision support.

Aquaculture is anticipated to be a critical element in future solutions to global food shortage. However, diseases can impede industry efficiency and sustainability. Consequently, diseases can and have led to dramatic re-structuring in industry or regulatory practices. The emergence of infectious salmon anemia (ISA) in Chile is one such example. As in other countries, many mitigations were instituted universally, and many incurred considerable costs as they introduced a new layer of coordination of farming activities of marine sites within common geographic areas (termed 'neighborhoods' or 'barrios'). The aggregate response led to a strong reduction in ISA incidence and impact. However, the relative value of individual mitigations is less clear, especially where response policies were universally applied and retrospective analyses are missing 'controls' (i.e., areas where a mitigation was not applied). Further, re-focusing policies around disease prevention following resolution of an outbreak is important to renew sustainable production; though, again, field data to guide this shift in purpose are often lacking. Expert panels can offer timely decision support in the absence of empirical data. We convened a panel of fish health experts to weight risk factors predictive of ISA virus (ISAV) introduction or spread between Atlantic salmon barrios in Chile. Barrios, rather than sites, were the unit of interest because many of the new mitigations operate at this level and few available studies examine their efficacy. Panelists identified barrio processing plant biosecurity, fallowing strategies, adult live fish transfers, fish and site density, smolt quality, hydrographic connection with other neighborhoods, presence of sea lice (Caligus rogercresseyi), and harvest vessel biosecurity as factors with the greatest predictive strength for ISAV virulent genotype ('HPR-deleted') occurrence. Fewer factors were considered predictive of ISAV HPR0 genotype ('HPR0') occurrence, with greatest strengths assigned to fish and site density, adult live fish transfers, and smolt facility HPR0 status. Field validation based on ISAV and risk factor occurrence after panel completion generally supports expert estimates, and highlights a few factors (e.g., broodstock HPR0 status) less conclusive in the original study. Results inform legislation, industry best management practices and surveillance design.

Simultaneous allergen inactivation and detoxification of castor bean cake by treatment with calcium compounds

Ricinus communis L. is of great economic importance due to the oil extracted from its seeds. Castor oil has been used for pharmaceutical and industrial applications, as a lubricant or coating agent, as a component of plastic products, as a fungicide or in the synthesis of biodiesel fuels. After oil extraction, a castor cake with a large amount of protein is obtained. However, this by-product cannot be used as animal feed due to the presence of toxic (ricin) and allergenic (2S albumin) proteins. Here, we propose two processes for detoxification and allergen inactivation of the castor cake. In addition, we establish a biological test to detect ricin and validate these detoxification processes. In this test, Vero cells were treated with ricin, and cell death was assessed by cell counting and measurement of lactate dehydrogenase activity. The limit of detection of the Vero cell assay was 10 ng/mL using a concentration of 1.6 x 10(5) cells/well. Solid-state fermentation (SSF) and treatment with calcium compounds were used as cake detoxification processes. For SSF, Aspergillus niger was grown using a castor cake as a substrate, and this cake was analyzed after 24, 48, 72, and 96 h of SSF. Ricin was eliminated after 24 h of SSF treatment. The cake was treated with 4 or 8% Ca(OH)2 or CaO, and both the toxicity and the allergenic properties were entirely abolished. A by-product free of toxicity and allergens was obtained.

Simultaneous allergen inactivation and detoxification of castor bean cake by treatment with calcium compounds.

Ricinus communis L. is of great economic importance due to the oil extracted from its seeds. Castor oil has been used for pharmaceutical and industrial applications, as a lubricant or coating agent, as a component of plastic products, as a fungicide or in the synthesis of biodiesel fuels. After oil extraction, a castor cake with a large amount of protein is obtained. However, this by-product cannot be used as animal feed due to the presence of toxic (ricin) and allergenic (2S albumin) proteins. Here, we propose two processes for detoxification and allergen inactivation of the castor cake. In addition, we establish a biological test to detect ricin and validate these detoxification processes. In this test, Vero cells were treated with ricin, and cell death was assessed by cell counting and measurement of lactate dehydrogenase activity. The limit of detection of the Vero cell assay was 10 ng/mL using a concentration of 1.6 x 10(5) cells/well. Solid-state fermentation (SSF) and treatment with calcium compounds were used as cake detoxification processes. For SSF, Aspergillus niger was grown using a castor cake as a substrate, and this cake was analyzed after 24, 48, 72, and 96 h of SSF. Ricin was eliminated after 24 h of SSF treatment. The cake was treated with 4 or 8% Ca(OH)2 or CaO, and both the toxicity and the allergenic properties were entirely abolished. A by-product free of toxicity and allergens was obtained.

TaqMan real-time RT-PCR detection of infectious salmon anaemia virus (ISAV) from formalin-fixed paraffin-embedded Atlantic salmon Salmo salar tissues.

The objective of this study was to evaluate the application of a TaqMan real-time reverse transcriptase PCR (RT-PCR) assay for the detection of infectious salmon anaemia virus (ISAV) in formalin-fixed paraffin-embedded (FFPE) fish tissues from Atlantic salmon Salmo salar with and without clinical signs of infection, and to compare it with histological and immunohistochemical (IHC) techniques. Sixteen fish samples obtained in 2007 and 2008 from 4 different farms in Chile were examined. The real-time RT-PCR allowed the detection of ISAV in FFPE samples from 9 of 16 fish, regardless of the organs analyzed, whereas 4 of the real-time RT-PCR negative fish were positive as indicated by histological examination and 3 of the real-time RT-PCR positive fish were negative as indicated by immunohistochemistry evaluation. The presence of ISAV in RT-PCR positive samples was confirmed by amplicon sequencing. This work constitutes the first report on the use of real-time RT-PCR for the detection of ISAV in FFPE sections. The assay is very useful for the examination of archival wax-embedded tissues, and allows for both prospective and retrospective evaluation of tissue samples for the presence of ISAV. However, the method only confirms the presence of the pathogen and should be used in combination with histopathology, which is a more precise tool. The combination of both techniques would be invaluable for confirmatory diagnosis of infectious salmon anaemia (ISA), which is essential for solving salmon farm problems.

Inhibition by diazepam of the effect of additional training and of extinction on the retention of shuttle avoidance behavior in rats.

Rats were submitted to a training and a test session in a shuttle avoidance task. In some groups, a second training session was interpolated 2 or 24 hr after the first session. In others, a session of extinction was interpolated 2 or 24 hr after the training session. When the interpolated task was 2 hr after training, training-test interval was 24 hr. When the interpolated task was 24 hr after training, training-test interval was 48 hr. The additional training enhanced, and the extinction depressed, retention test performance. Diazepam, given 30 min prior to the first (or only) training session enhanced the performance of avoidance responses in that session but inhibited it in the subsequent retention test. Diazepam given 90 min after training had no effect on retention. Diazepam given 30 min prior to either the additional training session or the extinction session did not affect performance in that session but cancelled their effects on retention test performance. The effects are related to the previously described prevention by diazepam of interfering effects on memory.

Memory facilitation by posttraining and pretest ACTH, epinephrine, and vasopressin administration: two separate effects.

Rats were trained in a step-down inhibitory avoidance task using a 0.3-mA, 2-s, 60 Hz footshock and tested 24 hr later. The animals received, 1 min after training and/or 5 min before testing, an ip injection of saline, ACTH (0.2 microgram/kg), lysine-vasopressin (10 micrograms/kg), epinephrine (5 micrograms/kg), naloxone (0.4 mg/kg), or a combination of naloxone with one of the hormones. Both the posttraining and the pretest injection of the hormones enhanced retention test performance; the enhancement was larger in animals that received the two treatments. Posttraining, but not pretest, naloxone administration also caused an enhancement. However, posttraining naloxone potentiated, and pretest naloxone antagonized, the effect of the concomitantly injected hormones. These data show that the posttraining and the pretest effect of the hormones are independent, are due to different mechanisms, and can be additive. In addition, it does not seem possible to explain posttraining memory facilitation by the hormones as owing to an addition to the reinforcement.

Post-training and pretest effects of adrenocorticotropin on retention: the influence of the hour of the day, the training-test interval, and pretest naloxone administration.

Rats received an ip injection of 0.2 microgram/kg of ACTH-(1-39) 1 min after step-down inhibitory avoidance training and/or 5 min prior to retention testing. Experiments were carried out either in the morning or in the afternoon using either a 3- or a 24-h training-test interval. Post-training ACTH induced memory facilitation in the morning and amnesia in the afternoon at both training-test intervals. Pretest ACTH reversed the afternoon amnesic effect, also at both training-test intervals. In addition, pretest ACTH induced a naloxone-reversible memory enhancement, both on its own and in animals treated with a facilitatory post-training dose of ACTH in the morning; this effect was seen only at the 24-h training-test interval. Naloxone had no effect of its own and did not influence the reversal of ACTH-induced amnesia caused by pretest ACTH in the afternoon. The results point to the variety of memory modulatory influences of ACTH, and to some of the factors involved in the elicitation of one or other effect, namely, the presumable basal rate of secretion of endogenous ACTH, and the previous pharmacological history of the animal.