Reviews in Aquaculture最新文献

Aquaculture is an essential source of protein and essential fatty acids for humans. However, the sustainable development of aquaculture faces numerous challenges, including a shortage of high-quality feed and feedstuff, and a degeneration in the safety and quality of aquatic products. This review explores how the use of microalgae as an aquafeed ingredient may help to solve these problems. Microalgae are a vital food source for larval bivalves, shrimps, and fish due to their high nutritional value and suitable cell size. Particularly, bivalves rely on microalgae as a direct feed source throughout their entire life cycle. Microalgae are also indispensable food sources or nutrient supplements for secondary live prey, including rotifers, Artemia, and copepods. Microalgae containing a large amount of protein and lipid can be used as alternatives to fishmeal and fish oil in aquafeed. Moreover, microalgae are rich in ω-3 polyunsaturated fatty acids, carotenoids, vitamins, and β-glucan. These bioactive substances can be used as feed additives to improve the growth rate, skin coloration, antioxidant capacity, immunity, and survival rate of aquatic animals. However, the high production cost of microalgae limits its widespread application in aquaculture. Recent advancements in the technology used to culture microalgae intensively, especially fermentation technology, have significantly improved the production efficiency and decreased the production cost. Therefore, accelerating the use of microalgae as aquafeed is crucial if sustainable aquaculture is to be achieved. The review concludes by discussing the opportunities and challenges involved in integrating microalgae into sustainable aquaculture and suggests a way forward.

Breeding has played an important role in the mariculture and industrialization of kelp in China. However, the current kelp breeding systems in China have encountered some problems relating to germplasm diversity, management, technological innovations, and regional co-operation. This review summarizes the main challenges, such as top-down and fragmented management of germplasm libraries, as well as private industry breeding without government regulations, inter-cultivar accidental admixing and genetic erosion, loss of heterozygosity due to repeated selection and self-crossing. We outline multiple potential approaches to breed cultivars with improved qualitative/quantitative traits which can be subjected to changing environments, for example: (i) establishing a national germplasm repository to enhance integrative collection and preservation of kelp resources; (ii) planning and implementing kelp breeding programmes according to strategic priorities and goal-orientations; (iii) optimizing a hybridization-based breeding pipeline to produce robust cultivars through the introgression of novel alleles and thus the expression of hybrid vigour; (iv) enriching the high-quality annotated reference genomes and functional analysis of trait-associated markers/loci to develop DNA-based breeding technologies; (v) developing new priming-based (e.g., thermal and disease resistance) bio-engineering breeding strategies to meet future unpredictable climate change; and (vi) breeding towards an ecological kelp-microbiome interaction-based technique to produce cultivars with enhanced performance and adaptability to environmental scenarios. Collectively, the lessons learned from kelp breeding in China and the solutions proposed here may not only potentially improve or re-invigorate the Chinese kelp industry, but will also assist other developing countries in taking corrective actions to develop a sustainable future kelp farming industry.

In recent years, aquaculture has seen tremendous growth worldwide due to technological advancements, leading to research and development of various innovations. Aquaculture farmers prioritise early diagnosis for timely treatment to achieve better productive and economic performance. Aquatic animal health experts still employ traditional diagnostic methods using visual diagnosis, cell culture, media culture, histopathology and serology. However, the developments of technologies in aquamedicine, such as sequencing, biosensors and CRISPR, have enabled rapid disease detection within minutes. Furthermore, integrating sensors, drones, artificial intelligence and the internet in aquaculture farm monitoring has helped farmers take decisive actions to improve production. Advancements in diagnostic techniques have significantly enhanced the efficient detection of bacterial, viral, parasitic and fungal diseases in aquatic animals. Moreover, monitoring water quality, aquatic animal health and animal behaviour on farms has become exceptionally streamlined with cutting-edge tools like drones, sensors and artificial intelligence. Summarising research and development in aquatic animal health and monitoring aids efficient technology adoption in aquaculture. With these advanced technologies' continued development and adoption in developed countries, the aquaculture industry is experiencing growth and increased efficiency, benefiting farmers and consumers in these regions. However, farmers and educators in developing countries lack information about these technologies. Training of agricultural educators and efficient dissemination of knowledge and technologies through advertising and publication in collaboration with companies is essential. This review delves into emerging technologies capable of replacing the conventional diagnostic and monitoring methods utilised in aquaculture. We also explore their strengths, limitations and potential future applications within aquaculture settings.

Oysters are one of the most commercially important shellfish species and have been cultured for thousands of years. Oyster aquaculture supports the major aquaculture industries in many countries. Over the last few decades, the oyster breeding and aquaculture industries have developed rapidly to meet the continually growing demand. Many researchers have made significant efforts toward the genetic improvement of commercially important traits in oysters. Some strains with fast-growing, disease-resistant, and stable shell-colours have been developed through selective breeding. Some hybrid varieties have been developed by crossing different geographical populations or cultivated strains. Several hybrids exhibit considerable genetic variation and improved productive performance. Additionally, polyploid induction technologies have been applied in the oyster aquaculture industry, which provides a useful tool for performance improvement and genetic containment of cultured stocks. At present, the development of molecular breeding also provides a great opportunity for oyster genetic improvement. These advances in oyster breeding have improved the quality of oysters, brought great economic benefits, and been conducive to the sustainability of oyster production. Nonetheless, there are still some limitations and obstacles in oyster breeding, such as infectious diseases, summer mortality, conservation of germplasm resources, environmental contamination, and climate change. The present review provides an overview of the current status, challenges, and prospects in oyster breeding.

Fish microbiome plays an important role in maintaining host homeostasis, with many bacterial functions directly linked to host fitness. Fish microbiome research is advancing fast, especially in the context of aquaculture where several stressors are known to disrupt stability of host-associated bacteria, prompting dysbiosis. Therefore, understanding the signatures of dysbiosis in different fish mucosae and their association with such stressors is fundamental to set up efficient health-monitoring strategies, as well as sound and objective working hypothesis for future research. Herein, we reviewed studies that employed culture-independent approaches to assess the effects of disease, chemotherapeutics and water quality changes on several diversity metrics of gut, skin and gill microbiomes. We conclude that increases in abundance of potential pathogens and changes to bacterial community structure are reliable indicators of dysbiosis in fish. The gut microbiome emerged as being highly susceptible to salinity changes and chemotherapeutics, whereas external microbiota seems to be more susceptible to dysbiosis caused by disease and temperature changes. Our analysis showed that treatments with tetracyclines and florfenicol are more likely to elicit severe dysbiosis compared to quinolones and disinfectants that cause lesser disturbance to fish microbiome. Bacterial diseases also frequently elicit severe dysbiosis (enteritis in particular), whereas parasitic diseases are far less deleterious. Regarding impacts on water quality, only changes to salinity and temperature are reasonably studied. Recent developments in metagenomics, that include a fast turn-around time of results, can be used to detect changes to fish homeostasis during critical periods of fish production, assisting aquaculture management.

Aquaculture in China has undergone significant evolution in recent decades, transitioning from traditional practices to a vital food production industry. Alongside the rapid growth of aquaculture in China, aquafeed production continues to expand swiftly. This review attempts to establish an overview of the history and achievements in aquaculture nutrition research and feed industry in China. The development of scientific concept and methodology, especially the advanced molecular biology technology guarantees the shift from traditional nutrition to molecular nutrition, and subsequently to precision nutrition in aquaculture nutrition research. This evolution has facilitated the formulation of effective strategies to enhance the growth, health and product quality of aquatic animals. The advancements of aquaculture nutrition research and feed industry have also been propelled by innovative research concepts rooted in principles such as the health and safety of aquatic animals, the quality of aquatic products, resource conservation and environmental friendliness, and the advancements in key processing technologies within the aquafeed industry. The future perspectives of the aquaculture nutrition research and feed industry in China are also proposed. The present work aims to provide a reference for promoting the development of aquaculture nutrition research and feed industry in China.

Microbial flocs (bioflocs) present in the water of intensive culture tanks are formed by a variety of microorganisms and other kinds of particulate organic matter, such as faeces and uneaten feed. During shrimp culture, biofloc concentrations increase. It has been reported that some level of control over biofloc levels, which can be quantified by the concentration of total suspended solids (TSS), is necessary for the adequate performance of the system. Some authors suggest that TSS concentrations below 600 mg L⁻¹ are more appropriate for the superintensive culture of the Pacific white shrimp Litopenaeus vannamei in biofloc technology (BFT). However, subsequent research results contradict some of the arguments supporting the suggested solids limits, for example, the impact of increased solids on gill obstruction and subsequent shrimp survival. Recent studies have also shown the relationship between the control of solids and other important aspects of the system not considered so far, such as the control of opportunistic bacteria. Therefore, this topic seems worthy of revisiting, and it will be helpful to find new guidance toward understanding the levels of bioflocs that should be kept in L. vannamei culture tanks. In this review, we addressed the reasons that led to the establishment and limitations of the current biofloc levels for L. vannamei culture. The effects of maintaining low and high levels of bioflocs on both shrimp performance and the culture system are also analysed. Finally, perspectives on the management of biofloc levels are discussed, highlighting the advantages and disadvantages of each proposed strategy.

Interspecies hybridization has been widely used in the development of aquaculture in fish species but there is not much impact in crustacean species. Several species of crustaceans that have been successfully crossed still have low hatching rates and the hybrids obtained have not met expectations. This review tries to summarize and analyse interspecific hybridization of cultured crustacean species (shrimps, lobsters, crayfish and crabs) and its potential for development of crustacean aquaculture production. The success of cross-breeding on several species of shrimp and lobster has been supported by artificial insemination technology. In crabs, artificial insemination cannot be applied and cross-breeding still relies on natural mating with an unstable success rate. In addition to cross-breeding in captivity, cross-breeding of crustacean species (shrimp, lobster, crayfish and crab) in nature has also been found. Interbreeding of crustacean species in nature cannot always be distinguished morphologically, hybrids between them can be known with certainty after carrying out molecular analysis. Even though the level of reproductive performance in cross-breeding of shrimp, lobster, crayfish and crab species is still low, cross-breeding efforts must be continued to obtain more information so that it can later be mapped which species have the potential to develop hybrids for cultivation. Furthermore, growth, reproductive performance, monosex hybridity and disease resistance are all hybrid parameters that must be evaluated.

Aquaculture creates ‘aquatic foods’ such as fish, shellfish, and seaweeds that are critical for food security. Gene editing using CRISPR-Cas9 has the potential to transform aquaculture by improving animal welfare, nutritional attributes, and farming efficiency, with benefits for environmental sustainability. However, gene editing also poses risks of harm via side effects on other important traits or genetic introgression into wild populations. Public acceptance of gene edited aquatic species will rapidly erode if risk mitigation is ineffective or not applied. Here, we review the benefits and risks for gene editing in aquaculture. A general framework for risk–benefit analysis of gene editing in aquaculture is proposed, incorporating nine key considerations: genetic impacts, ecological impacts, disease risk mitigation, nature of edit, supply chain environmental footprint, animal welfare, human nutrition, ethical business implications and impacts on local communities. When applied on a case-by-case basis, the framework will help identify how gene editing of a farmed species can most enhance production and nutritional benefits while minimising harms to animal welfare, the environment, and society.