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Litopenaeus vannamei , with high plant protein acceptance and high global aquaculture production, is a potential species for rapeseed meal application. However, rapeseed meal has been associated with anorexia in fish, and whether the same occurs in L. vannamei remains unknown. This study demonstrated the effects of rapeseed meal on the feeding and anorexigenic endocrine of L. vannamei based on feeding behavior and transcriptomics. Soybean meal was replaced with fermented rapeseed meal (50%), and a significant increase in remaining diet and dietary discard was observed with a significant reduction in dietary visits. Transcriptome analysis revealed that the pathways involved in rapeseed meal-induced anorexia mainly included signal transduction, the digestive system, the sensory system, the endocrine system, phototransduction-fly, the thyroid hormone signaling pathway and pancreatic secretion. Moreover, this study further analyzed and identified seven neuropeptides involved in rapeseed meal-induced anorexia, and it explored the complex expression regulation strategies of these neuropeptides. In summary, this study confirmed through feeding behavior that rapeseed meal causes anorexia in L. vannamei , and it identified seven neuropeptides that were closely related to the anorexia process.

White Spot Syndrome Virus (WSSV) continues to cause considerable loss to shrimp farmers globally with frequent outbreaks even in specific pathogen free Peneaus vannamei. Our studies showed that the bodyweight (BW) of PL has a bearing on their susceptibility to the virus. To test this hypothesis, PL of the same age group and family were grouped according to BW (10-20, 30-40, and 50-60 mg) and challenged through immersion route with two viral doses (10 6 and 10 7 virus copies/L of water). It was observed that the PL became susceptible to WSSV at ≥50 mg BW. In the 50-60 mg PL group, the higher challenge dose shows a sharp mortality curve with 100% mortality at 10 days post immersion, while the lower dose shows a steady increase in cumulative mortality that reaches 100% on the 13th day post immersion. The study also brings out that an in vivo viral load of approximately 3.5 to 4.5 × 10 7 WSSV copies/100 ng shrimp DNA results in mortality. This is the first report on the relationship between BW and WSSV susceptibility in shrimp PL. Also reported here is a quantitative assessment of WSSV infection in P. vannamei PL and an optimized challenge protocol., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

Probiotic feed additives can support the gut health of shrimp and thereby improve performance, production efficiency and disease resistance. Two experiments in white leg shrimp aimed to investigate the effects of a multi-species probiotic feed supplement (AquaStar ® , 3 g/kg feed, Biomin GmbH, Getzersdorf, Austria) in feed formulations with different marine meal levels (32% and 15%) on growth performance and resistance against Vibrio parahaemolyticus . Juvenile shrimp were stocked in a recirculating aquaculture tank system at a density of 20 shrimp/46.8 L and were fed diets with and without the probiotic supplementation for 8 weeks. Afterwards, a bath immersion with V. parahaemolyticus was performed and mortality was observed over a period of 14 days. Independent of the diet formulation, probiotic supplementation significantly improved the survival rate of the shrimp and the specific growth rate while decreasing feed consumption and feed conversion ratio when compared to the control ( p ≤ 0.042). After the Vibrio immersion challenge, mortality was significantly decreased by 13.33% with probiotic supplementation in the high marine meal diet experiment ( p = 0.042) and numerically decreased by 11.67% in the low marine meal diet experiment ( p = 0.133). Overall, the results suggest that the beneficial effects of the probiotic can occur independently of the diet formulation.

Viral diseases have seriously restricted the healthy development of aquaculture, and decapod iridescent virus 1 (DIV1) has led to heavy losses in the global shrimp aquaculture industry. Due to the lack of effective treatment, early detection and regular monitoring are the most effective ways to avoid infection with DIV1. In this study, a novel real-time quantitative recombinase polymerase amplification (qRPA) assay and its instrument-free visualization improvement were described for the rapid detection of DIV1. Optimum primer pairs, suitable reaction temperatures, and probe concentrations of a DIV1-qRPA assay were screened to determine optimal reaction conditions. Then, its ability to detect DIV1 was evaluated and compared with real-time quantitative polymerase chain reactions (qPCRs). The sensitivity tests demonstrated that the limit of detection (LOD) of the DIV1-qRPA assay was 1.0 copies μL -1 . Additionally, the presentation of the detection results was improved with SYBR Green I, and the LOD of the DIV1-RPA-SYBR Green I assay was 1.0 × 10 3 copies μL -1 . Both the DIV1-qRPA and DIV1-RPA-SYBR Green I assays could be performed at 42 °C within 20 min and without cross-reactivity with the following: white spot syndrome virus (WSSV), Vibrio parahaemolyticus associated with acute hepatopancreatic necrosis disease ( V p AHPND ), Enterocytozoon hepatopenaei (EHP), and infectious hypodermal and hematopoietic necrosis virus (IHHNV). In conclusion, this approach yields rapid, straightforward, and simple DIV1 diagnoses, making it potentially valuable as a reliable tool for the detection and prevention of DIV1, especially where there is a paucity of laboratory equipment.

Currently, count size is applied globally as a grading standard to sell head-less shell-on farmed shrimp. Although count size does not indicate directly the quality of shrimp, the price of shrimp generally increases proportionally with the increase of shrimp size. The importance of the size of white leg shrimp has been previously reported, where a strong correlation was found between size and metabolome data. In this study, we aimed to improve the predictive power of the orthogonal projection to latent structure (OPLS) model by expanding the metabolite coverage using liquid chromatography mass-spectrometry (LC/MS) and gas chromatography-mass spectrometry (GC/MS) analysis. The training set consisted of 11 different-sized white leg shrimps from Indonesia and was validated in a step-wise manner by introducing an independent dataset consisting of commercial shrimp from the Japanese market. The first validation set consisted of commercial white leg shrimp, resulting in standard deviation error estimation and prediction values of 1.648 and 2.617, respectively. IMP and AMP, which are metabolites responsible for the umami taste in crustaceans, showed the highest variable importance in projection (VIP) scores and positively correlated with the increase in shrimp size. The second validation was carried out to evaluate the applicability of the size-metabolome relationship to other commercial penaeid shrimp species. The commercial black tiger shrimps with count sizes of 31/40, 21/25, 16/20, and 13/15 failed to predict the size of shrimp, suggesting that the importance of size in relation to the metabolome profile was rather species-specific., (Copyright © 2022 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

The polysaccharide-fucoidan plays a fundamental role in shrimp aquaculture by being used as a natural immunostimulant and dietary supplementation. In this study, Cystoseira trinodis fucoidan (FCT) was extracted, its structure was determined using FT-IR analysis, and its effect of fucoidan on growth performance and WSSV resistance in Litopenaeus vannamei was evaluated. Four experimental diets, including the control (without FCT), 0.1, 0.2, and 0.4% FCT, were formulated and fed to shrimps for 60 days. Next, they were exposed to WSSV, and their mortality rate was noted daily up to 20 days. The results of the growth experiment demonstrated a significant increase in the final weight, WG, and SGR, and a lower FCR in treatments than in control. During the challenge trial, 100% mortality was recorded in control within ten days. However, FCT-treated shrimps indicated a mortality increase from 43.33 to 75.00% during 20 days of infection. The immunological and biochemical parameters and the expression of immune-related genes in individuals fed the FCT-incorporated diet considerably (p < 0.01) improved over control before the challenge (0 days) and after the challenge on days 5, 10, 15, and 20. It was concluded that L. vannamei fed on diets supplemented with all concentrations of FCT (especially 0.4%) had improved the growth, immunological and biochemical parameters, and the expression of immune-related genes, as well as enhancing the resistance against WSSV., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

This study was aimed at comparatively analyzing the sterols, tocopherols and fatty acids from edible flesh and processing waste obtained from three shrimp species, utilizing rapid liquid chromatography (LC)-atmospheric-pressure chemical ionization (APCI)-tandem mass spectrometry (MS/MS) and gas chromatography-mass spectrometry (GC-MS). Results revealed the presence of significantly ( p < 0.05) high proportions of health-beneficial omega-3 (n3) polyunsaturated fatty acids (PUFAs) in Argentine red shrimp (34.3% in waste and 38.2% in the flesh), compared to black tiger shrimp (16.5-24.2%) and whiteleg shrimp (13.2-22.6%). Among sterols, cholesterol was found most dominant, accounting in the range 349.4 (white shrimp flesh) to 559.3 µg/g fresh weight (FW) (black shrimp waste). Surprisingly, waste was found to contain a substantially higher amount of α-tocopherol, for instance, 21.7 µg/g FW in edible flesh and 35.3 µg/g FW in the waste of black tiger shrimp. The correlation analysis indicated that shrimp with low total contents of lipids might have higher proportions of health-beneficial long-chain (LC)-n3-PUFAs eicosapentaenoic (EPA) and docosahexaenoic acid (DHA). The fat quality indices, including the high ratios of hypocholesterolemic (h)/hypercholesterolemic (H) fatty acids, and lowest values of the atherogenic index (AI) and thrombogenic index (TI) indicated the health-beneficial potential associated with fat intake from red shrimp. Overall, a significant amount of health-beneficial compounds in edible flesh of studied shrimp confers its extraordinary nutritional benefits. Moreover, considering the richness of processing waste with these compounds, their valorization can be prompted.