Impact of Global Warming on the Severity of Viral Diseases: A Potentially Alarming Threat to Sustainable Aquaculture Worldwide

With an ever-increasing human population, food security remains a central issue for the coming years. The magnitude of the environmental impacts of food production has motivated the assessment of the environmental and health benefits of shifting diets, from meat to fish and seafood. One of the main concerns for the sustainable development of aquaculture is the emergence and spread of infectious animal diseases in a warming climate. We conducted a meta-analysis to investigate the influence of global warming on mortality due to viral infections in farmed aquatic animals. We found a positive trend between increasing temperature and increasing viral virulence, with an increase in water temperature of 1 °C resulting in an increase in mortality of 1.47–8.33% in OsHV-1 infected oysters, 2.55–6.98% in carps infected with CyHV-3 and 2.18–5.37% in fishes infected with NVVs. We suggest that global warming is going to pose a risk of viral disease outbreaks in aquaculture and could compromise global food security

An EST resource for tilapia based on 17 normalized libraries and assembly of 116,899 sequence tags

<p>Abstract</p> <p>Background</p> <p>Large collections of expressed sequence tags (ESTs) are a fundamental resource for analysis of gene expression and annotation of genome sequences. We generated 116,899 ESTs from 17 normalized and two non-normalized cDNA libraries representing 16 tissues from tilapia, a cichlid fish widely used in aquaculture and biological research.</p> <p>Results</p> <p>The ESTs were assembled into 20,190 contigs and 36,028 singletons for a total of 56,218 unique sequences and a total assembled length of 35,168,415 bp. Over the whole project, a unique sequence was discovered for every 2.079 sequence reads. 17,722 (31.5%) of these unique sequences had significant BLAST hits (e-value < 10^-10) to the UniProt database.</p> <p>Conclusion</p> <p>Normalization of the cDNA pools with double-stranded nuclease allowed us to efficiently sequence a large collection of ESTs. These sequences are an important resource for studies of gene expression, comparative mapping and annotation of the forthcoming tilapia genome sequence.</p

Fish farming as a way for diversifying sources of income in the cocoa sector in Côte d'Ivoire

&lt;p&gt;Côte d'Ivoire is the largest producer of cocoa in the world, with production reaching 2 million tonnes in 2016-2017. The South- and Central-West regions are the main cocoa production areas in the country. However, cocoa production faces a significant crisis due to the instability of prices on world markets, land saturation, ageing plantations, and climate change. Cocoa farmers have adopted fish farming as an additional production to generate new incomes. The objective of our study was to provide the first description of cocoa production diversification practices in Côte d'Ivoire through targeted questionnaires. Surveys were conducted from May 2021 to September 2021 with cocoa farmers practising fish farming in two localities of Central-West: Bédiala (n = 21) and Sinfra (n = 12) and one in South-West: Méagui (n = 12). We used an empirical approach to highlight the farming practices. Our first results showed that all the cocoa farmers interviewed in Bédiala and 67% of the cocoa farmers in Sinfra practice fish-rice farming in which rice and tilapia (&lt;i&gt;Oreochromis niloticus&lt;/i&gt;) are cultivated in the same ponds. In addition, the cocoa plantations in Bédiala (90%) and Sinfra (75%) are characterised by the association of cocoa and cashew for shading cocoa plants. Among the cocoa farmers interviewed in the South-West region, 50% of them practise fish-rice farming, with the monoculture of cocoa. With incomes ranging between 300 to 6000 kFCFA per year, fish farming has become the primary source of revenues for 30%, 40%, and 5% of cocoa farmers in Bédiala, Sinfra, and Méagui, respectively. In such agriculture-aquaculture integrated systems, most of the farmers use the periphery of the ponds in the dry season as cocoa nurseries, which allows the young crops to benefit from fertilised pond water collected by their roots. Such practices are likely to enhance crop growth while reducing the watering effort. In addition, fish ponds act as a natural barrier against bush fires. These results highlight the positive interactions that exist between cocoa and fish farming. Nevertheless, the consequences of using phytosanitary products in cacao production near fish ponds remain to be assessed for human consumers and surrounding environments. Based on a Strengths, Weaknesses, Opportunities, Threats (SWOT) analysis, we explore the possibilities that may be more promising for cocoa production diversification in Côte d'Ivoire.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Keywords:&lt;/strong&gt; Aquaculture, cocoa farming, diversification&lt;/p&gt

Application of the FTA elute card coupled with visual colorimetric loop-mediated isothermal amplification for the rapid diagnosis of Streptococcus agalactiae in farmed tilapia (Oreochromis niloticus)

A method combining the FTA Elute card and visual colorimetric loop-mediated isothermal amplification (FTA-e/LAMP) was tested to diagnose Streptococcus agalactiae infections in vitro and in vivo. FTA-e/LAMP consists of two main steps: first, the FTA card is used to extract DNA and then a colorimetric loop-mediated isothermal amplification (LAMP) reaction is carried out on the extracted DNA. In vitro sensitivity was 1.9 x 10(2) CFU/mL, and regarding specificity, all nine S. agalactiae strains tested positive. All Streptococcus spp. tested negative, except for S. dysgalactiae, thereby indicating the need for another set of primers to distinguish this species from S. agalactiae. To diagnose S. agalactiae infections using FTA-e/LAMP in vivo, two experimental trials on juvenile Oreochromis niloticus infected with bovine or piscine strains were carried out. Sensitivity in symptomatic fish was 100%, and 50.7% of fish without signs were positive. All negative control fish tested negative (n = 28). No bacteria were detected after 16 days post-infection (dpi). Accuracy during the first week (1-7 dpi) was 89% and decreased to 44% thereafter (10-22 dpi). FTA-e/LAMP results suggest that this method is a promising tool for early and fast diagnosis of S. agalactiae on tilapia farms

Estimation of body weight of European sea bass (Dicentrarchus labrax) and Nile tilapia (Oreochromis niloticus) larvae by image analysis

The present study aimed to develop nondestructive methods to accurately follow the growth of fish larvae and post-larvae. European sea bass (Dicentrarchus labrax) aged 71-100 days post fertilization (dpf; 20-419 mg) and Nile tilapia (Oreochromis niloticus) aged 14 dpf (10-25 mg) were used as model species. Several measurements were performed on digital pictures of larvae to model body weight. Using body surface area, contour, length and depth, it was possible to estimate accurately the body weight of young European sea bass and Nile tilapia (r² of 0.98 and 0.95, respectively)

Sex determination and sex differentiation in tilapias.

International audienc

A one-health approach to non-native species, aquaculture, and food security

One-Health is an umbrella term that integrates the health of the environment, humans and non-human animals. This approach is applied here to elucidate the impact of non-native invasive species on aquaculture and food security. Despite inherent biases against these species, a better understanding of their characteristics allows for the identification of those of greatest concern, minimizing the risk of food shortages and infectious diseases. This review summarises the positive and negative impacts of non-native species, delineating the specific areas they may impact. Additionally, this review gives an insight to the expertise and stakeholders that would need to be included if a “One-Health” approach were to be implemented by policymakers to better control non-native species.Detailed examples illustrate the consequences of non-native species on trophic dynamics, ecosystem health, water chemistry, and human health, emphasizing the importance of managing them within a multidimensional framework. The “One-Health” approach is explained, and suggestions are made on how certain non-native species could be used to contribute to food security in low- and middle-income countries. Furthermore, recommendations are made to promote a more inclusive management strategy

Adaptation to extreme salinity variations in tilapias.

International audienc