Temporal and spatial progress of the diseases caused by the crinivirus tomato chlorosis virus and the begomovirus tomato severe rugose virus in tomatoes in Brazil

Efficient management of whitefly-borne diseases remains a challenge due to the lack of a comprehensive understanding of their epidemiology, particularly of the diseases tomato golden mosaic and tomato yellowing. Here, by monitoring 16 plots in four commercial fields, the temporal and spatial distribution of these two diseases were studied in tomato fields in Brazil. In the experimental plots these diseases were caused by tomato severe rugose virus (ToSRV) and tomato chlorosis virus (ToCV), respectively. The incidence of each virus was similar in the plots within a field but varied greatly among fields. Plants with symptoms for both diseases were randomly distributed in three of four spatial analyses. The curves representing the progress of both diseases were similar and contained small fluctuations, indicating that the spread of both viruses was similar under field conditions. In transmission experiments of ToSRV and ToCV by Bemisia tabaci MEAM1 (former biotype B), these viruses had a similar transmission rate in single or mixed infections. It was then shown that primary and secondary spread of ToCV were not efficiently controlled by insecticide applications. Finally, in a typical monomolecular model of disease progress, simulation of the primary dissemination of ToSRV and ToCV showed that infected plants were predominantly randomly distributed. It is concluded that, although the manner of vector transmission differs between ToSRV (persistent) and ToCV (semipersistent), the main dispersal mechanisms are most probably similar for these two diseases: primary spread is the predominant mechanism, and epidemics of these diseases have been caused by several influxes of viruliferous whiteflies.     

Innovation strategies for smart specialisation (RIS3): Past,present and future research

The recent change in the regional development strategy of the European Union (EU) results in an important need to study the terms of change and their respective implications. This study seeks, through a bibliometric analysis, to ascertain the developments taking place in studies on research and innovation strategies for smart specialisation (RIS3) to identify shortcomings and opportunities for future research. This bibliometric review drew upon the Scopus database with the sample selected containing all the articles containing the keywords “Research and Innovation Strategies for Smart Specialisation” or “RIS3.” This correspondingly reports how some authors maintain that the path the EU should take involves imitative innovation. Meanwhile, others propose that each region should specialise in those industries that are already established there and thus avoid targeting any areas they do not already know/specialise in. Our findings detail six clusters in RIS3 research, which help in contextualising the literature review: (a) business discovery; (b) smart specialisation; (c) innovation; (d) specialisation; (e) regional policies; and (f) regional development. This study furthermore sets out perspectives for future lines of research and correspondingly seeks to convey a vast theoretical basis that may serve as the point of departure for future studies.     

Soil quality assessments in integrated crop–livestock–forest systems: A review

Integrated crop–livestock–forest is a promising strategy to improve soil quality. It comprises four different integrated farming systems: crop–livestock, crop–forest, forest–livestock and crop–livestock–forest. This work systematically reviewed studies about integrated crop–livestock–forest systems and soil quality. A total of 92 papers were retrieved from the Web of Science—Clarivate Analytics platform, and the following information was analysed: publication year, institution, region of the studied site, type of integrated system, soil type, tillage system, maximum soil depth and the soil quality indicators assessed. Most studies were published in the second half of the 2010s. Brazil is a prominent focus of research about soil quality and integrated crop–livestock–forest systems, with significant contribution from its central and southern regions. The Embrapa was the main publishing institution, present in over one‐third of the studies. Crop–livestock was the most common integrated system, Ferralsols was the most common soil group, and most of the studied soils were clayey. No tillage was the main tillage system. Most studies focused on the topsoil, assessing physical and/or chemical soil quality indicators. More emphasis on biological indicators of soil quality is required, as well as assessments integrating biological, physical and chemical indicators of soil quality. Future works should compare different integrated systems, including assessments deeper in the soil profile, especially in systems with the forest component, and also in sandy and silty soils. Soil quality indicators that have been rarely used should be further tested. Novel indicators should be added to better understand the promotion of soil quality by integrated crop–livestock–forest systems.     

Homeopathic complex increases survival without affecting the performance of Nile tilapia during masculinization

During the masculinization of Nile tilapia, Oreochromis niloticus, the effect of a homeopathic complex (containing Chamomilla, Quina, and sulphur) was evaluated based on survival, performance, gills and liver integrity, and parasitism. Group fed with basal diet + 17 alpha-methyltestosterone (control) showed low survival (40.02%), while the group that additionally received homeopathy and the group that received sucrose (vehicle) showed 73.7% and 87.7% survival, respectively. The growth performance of the group that received homeopathic and the control group was significantly higher than that of the group that received only sucrose. Still, fish that received the homeopathic complex showed higher branchial and hepatic integrity as compared to the other groups. The homeopathic complex contributes to a greater survival of fish in addition to maintaining satisfactory growth. Furthermore, homeopathy contributes to the improvement in gill and liver integrity of the Nile tilapia larvae.     

Antioxidant activity and lipid peroxidation in Artemia nauplii enriched with DHA‐rich oil emulsion and the effect of adding an external antioxidant based on hydroxytyrosol

Artemia nauplii catabolize polyunsaturated fatty acids (PUFA); in particular, they retroconvert docosahexaenoic acid (DHA, 22:6n‐3), so enrichment is a continuous quest towards increasing PUFA through the use of PUFA‐rich enrichment products. However, optimal conditions during enrichment (aeration, illumination and temperatures around 28°C) tend to accelerate autoxidation of PUFA and the formation of potentially toxic oxidation products. Water‐soluble antioxidants like the polyphenolic compound hydroxytyrosol (3,4‐dihydroxyphenylethanol), a polar molecule found in the water fraction resulting after the milling process of olives, arise as promising compounds to prevent oxidation during Artemia enrichments. We investigated the antioxidant activity and lipid peroxidation in Artemia nauplii during enrichment and the effect of adding an external antioxidant based on hydroxytyrosol during the enrichment with a PUFA‐rich emulsion (M70). For this purpose, the activity of antioxidant enzymes (catalase, superoxide dismutase, glutathione‐S‐transferase, glutathione peroxidase), as well as lipid peroxidation, was determined in enriched and unenriched Artemia nauplii. To validate antioxidant activity and lipid peroxidation, in a first experiment, nauplii were enriched with microalgae (Tetraselmis suecica), yeast (Saccharomyces cerevisiae) and M70 emulsion. In a second experiment, enrichment with a commercial emulsion (DC Super Selco), M70, and a combination of M70 and hydroxytyrosol (Hytolive, HYT) added as an external antioxidant were performed. The combination of M70 with HYT produced the best results, in terms of activity of antioxidant enzymes. The analysis of the fatty acids from total lipids showed that the addition of hydroxytyrosol preserved the DHA percentage of enriched nauplii.     

Nutritional Contribution of Biofloc within the Diet of Growout and Broodstock of Litopenaeus vannamei,Determined by Stable Isotopes and Fatty Acids

The relative contributions of feed sources were determined through the isotopic signal (δ¹³C and δ¹⁵N) and fatty acid profile of feed items, shrimp muscle, and eggs of Litopenaeus vannamei reared in a biofloc system. In the growout phase, the isotope analysis showed the biofloc particle size class ≥250 μm contributed 55–100%; size ≥50 < 250 μm contributed 0–22%; and artificial feed contributed 0–45%. Principal component analysis applied to fatty acid profiles showed that biofloc ≥250 μm and artificial feed were the most important items in shrimp growout. For the egg production, isotope analysis suggested that the most important feed sources according to their relative contributions were polychaetes (0–100%), followed by artemia biomass (0–86%) and semi‐moist feed (0–66%), with lower contributions from squid, mussel, and the muscle of L. vannamei broodstock that had been cultured in biofloc. In terms of fatty acids, the most important items were artemia, polychaetes, and semi‐moist feeds. This work clarified the importance of feed sources for shrimp during culture in biofloc systems and during reproduction. Analysis of stable isotopes and fatty acids can be successfully used to trace the assimilation of nutrients during the nutrition of shrimp.     

Factors affecting the reproductive efficiency in crayfish: implications for aquaculture

In recent years, crayfish aquaculture industry has been developing rapidly in different regions of the world. Crayfish aquaculture is often carried out in dams, lakes and extensive pond systems. There is an increasing demand for crayfish juvenile in aquaculture sector. Therefore, it is important to know which factors affect reproductive efficiency in crayfish. In the present review, factors affecting the reproductive efficiency of crayfish are divided into two main sections, external and internal factors. Dietary lipids, phospholipids, highly unsaturated fatty acids, protein and amino acids, vitamins and carotenoids are important external factors affecting broodstock crayfish reproduction. In addition, various external (i.e. female size, stocking density, temperature, photoperiod, sex ratio) and internal (i.e. endogenous hormones) factors affect the reproductive efficiency in crayfish. This study reviews the present knowledge with the purpose of realizing the factors that are important to reach optimal crayfish nutrition, maturation and reproduction (i.e. pleopodal egg number and quality). This review will particularly be useful for crayfish farmers and crayfish hatchery units.     

Histological alterations in gills of shrimp Litopenaeus vannamei in low‐salinity waters under different stocking densities: Potential relationship with nitrogen compounds

Two experimental modules with different stocking densities (M1 = 70 and M2 = 120 shrimp /m²) were examined weekly over a culture cycle in tanks with low‐salinity water (1.9 g/L) and zero water exchange. Results showed survival rates of 87.7 and 11.9% in M1 and M2, respectively. Water temperature, pH, dissolved oxygen, electrical conductivity and chlorophyll a were not significantly (p > .05) different between modules. In contrast, the concentrations of nitrogen compounds were significantly (p < .05) different between modules, except nitrite‐N (M2 were 2.31 ± 1.38 mg/L N‐TAN, 0.18 ± 0.49 mg/L N‐NO₂^? and 6.83 ± 6.52 mg/L N‐NO₃^?; in M1: 0.97 ± 0.73 mg/L N‐TAN, 0.05 ± 0.21 mg/L N‐NO₂^? and 0.63 ± 0.70 mg/L N‐NO₃^?). When waters of both modules reached higher levels of ammonia and nitrite, histological alterations were observed in gills. The histological alterations index (HAI) was higher in M2 (5‐112) than in M1 (2‐22).