Reviews in Aquaculture最新文献

The replacement of fish oil with plant oils is a common practice in aquaculture to compensate for the shortage of fish oil supply and has been thoroughly studied. However, because the experimental conditions vary in many aspects, the results are usually inconsistent quantitatively. Therefore, a meta-analysis was conducted based on a dataset containing 328 articles to systematically model the influence of plant oils on the main aquaculture fish. In addition to demonstrating the species-specific dose-dependent impact of plant oils on fish growth, feed utilization efficiency, lipid deposition and health parameters, we have also investigated the role of other factors in this process. We found that the adverse effects caused by plant oils worsen as the experimental duration extends for Atlantic salmon, while Gilthead seabream and European seabass gradually adapt to the change. Further, water temperature could be a decisive factor for Rainbow trout, and early adaptation to plant oils would be helpful for Gilthead seabream. Moreover, sufficient fishmeal supply could alleviate the adverse effects caused by plant oils for most species, but for Gilthead seabream and European seabass, the growth suppression effect of plant oil was larger when fed high-fishmeal diets. Besides, by comprehensively considering the effects of plant oils, we matched the potential optimal plant oil for each fish species. Our article quantitatively modelled the adverse effects of replacing fish oil with plant oils, investigated the influences of assistant factors and offered a panorama of the research status with emphasis on potential breakthrough orientations.

The life history, distribution and diversity of fishes are largely influenced by environmental salinity. Changes in salinity affect a range of physiological processes including metabolism, nutrition, reproduction and growth. Therefore, fish can be conditioned to environmental parameters most suitable for production, where distinct traits are optimised through species-specific manipulation of salinities. The primary purpose of this review is to summarise the existing literature on the salinity tolerance of aquacultured fish. The various experimental approaches for determining salinity tolerance are compared, along with summarised information for key species employed in aquaculture, including their native distributions, life history stage and optimal salinity for survival and growth. The implications for production were assessed by considering the effects of salinity on growth, reproduction, management, disease mitigation and marketability.

Aquaculture plays an important role in meeting human demand for animal protein. Disease is a critical factor that restricts the green and healthy development of aquaculture. Intensive aquaculture practices can increase the susceptibility of aquatic animals to pathogens due to environmental stress. Antibiotics are commonly used for disease prevention and control, but their frequent use in aquaculture can increase the risk of antibiotic-resistant bacteria and resistance gene transmission, posing a threat to the health of aquatic animals and humans. Recent studies have shown that bacteriocins have inhibitory effects on different species of bacteria, fungi and viruses, and can even affect natural resistance structures such as bacterial biofilms, presenting promising prospects as antimicrobial agents. Bacteriocins have potential applications in various fields such as agriculture, food and medicine, but limited research has been conducted on their impact on aquaculture disease prevention and control, and the underlying mechanisms remain to be explored. Therefore, this review aims to summarise the classification, sources, preparation methods, antibacterial activity against multidrug-resistant bacteria and application of bacteriocins as antimicrobial agents in aquaculture disease prevention and control. In addition, limitations of bacteriocin application in aquaculture and future research directions are also discussed.

Aquaculture provides an important and expanding source of protein rich and healthy food to the world. However, to minimize environmental harm from aquaculture, interactions with wild fish communities need to be thoroughly assessed. Here, we characterize the existing knowledge pertaining to such interactions, exemplified with Atlantic salmon (Salmo salar) farming in open net pens along the Norwegian coast and potential consequences for wild Atlantic cod (Gadus morhua) populations. Importantly, the wild cod fishery also provides a protein rich, high quality food source with high economic value. We identify seven risk sources that may affect behaviour, physiology, and survival in wild cod. Of particular importance is the large amount of waste feed that causes wild fish to aggregate around farms, thereby altering a multitude of ecological interactions including predation and disease transmission. Moreover, altered food quality in pellets may alter physiological processes and cause mortality to vulnerable life-stages in wild cod. More research is needed on mechanisms and thresholds for harm. As the most important cod fisheries are found in northern Norway, where climate change also is rapid, we expect stronger and potentially more harmful interactions between fish farming and wild cod fisheries as aquaculture continues to expand. We hope that our analysis will inspire further research, on farmed salmon and wild cod interactions, but also on aquaculture and wild fish interactions in general. Such research is fundamental for the development of management systems that can reduce the impact of aquaculture on fisheries and the environment.

Polyculture is a relevant practice for improving the sustainability of aquaculture, which raises interest in implementing it in a variety of production systems. However, polyculture is a complex approach that can result not only in complementarity among species but also competition among them and animal welfare issues. Potential polyculture benefits can be expected provided that compatibility and complementarity occur among the combined species. This places a premium on identifying the best species combinations for a given aquaculture system. Here, we developed a conceptual integrative workflow to standardise and plan the development of new fish polycultures. This workflow is designed to screen all possible combinations in a set of species based on three successive steps of assessment. Overall, these steps consider the compatibility and complementarity of co-farmed species as well as stakeholder demands, sustainability and fish welfare. Step 1 consists of selecting the most promising compatible species combinations (i.e., ‘prospective combinations’) as a function of stakeholder opinion and expectations using databases and surveys. Step 2 validates the effectiveness of prospective combinations based on bioassays by considering species complementarity and animal welfare. Step 3 implements the best species combination(s) in aquaculture production, during which prototyping allows the sustainability of the resulting commercial production system to be studied. In conclusion, the workflow aims at being a valuable tool to innovate in aquaculture by exploiting the opportunities and the strengths of polyculture.

Periods of fasting occur for a multitude of reasons in Atlantic salmon aquaculture. Feed withdrawal is widely used prior to transport, parasite treatments, preslaughter and for depuration purposes in recirculating aquaculture systems. Voluntary fasting is a coping response when fish have poor health or are exposed to poor farm environments. Owing to increased attention to animal welfare in aquaculture, concerns have been raised regarding ethical issues when farmed fish are subjected to fasting. However, thorough science-based recommendations for fasting and feed-withdrawal regimes have been lacking. The purpose of this review is to provide a synthesis of the various causes for fasting in Atlantic salmon aquaculture and evaluate their associated welfare implications so that guidelines for appropriate practices can be formulated. To interpret impacts, we describe biological responses and tolerance limits to fasting in Atlantic salmon and consider adaptations in the wild. Fry and parr are highly sensitive to feed withdrawal. However, post-smolts and adults are well-adapted to endure prolonged fasting without experiencing compromised functionality or health. Here, short periods of feed withdrawal prior to operations should therefore not constitute significant welfare concerns. Serious concerns are instead associated with voluntary fasting that may continue for weeks. We emphasize that environmental extremes that exceed appetite impairing thresholds must be avoided. Additionally, farmed fish should not be subjected to practices that lead to chronic stress that induce cessation of appetite. Diseases or parasites that impair appetite should also be mitigated. Fasting is here a symptom rather than a cause for poor welfare.

Improving feed suitability and bolstering the global upsurge in fish production is a strategic challenge for aquaculture. The utilization of plant and animal derived ingredients in aquafeed for achieving sustainable in finfish aquaculture is affected by various factors, including the presence of antinutritional factors, lowered nutrient bioavailability, indigestible particles and microbial contaminants. Applying fermentation to overcome these problems in aquafeed ingredients has received considerable attention in recent years as fermentation provides health-promoting probiotic benefits to host organisms. Fermentation has also been shown in many studies to improve nutrient availability and bioavailability of feed, increased palatability and digestibility and eliminate anti-nutritional compounds in dietary feed ingredients, making them more easily digestible which eventually improve growth and health performance of fish. Therefore, it is imperative to accelerate the use of fermented feedstuffs as aquafeed if sustainable aquaculture is to be achieved. This review reported the various methods of fermentation, characteristics of fermented feed ingredients, factors that are considered during fermentation and overall nutritional quality of fermented feed ingredients for aquaculture production. The role of fermented feed ingredients for various farmed species in terms of growth, feed utilization, gut microbiota composition, immunity and disease resistance in fish is thoroughly discussed. The possible drawbacks associated with the fermentation process are also discussed in the article.

The holobiont theory expands the notion of individual multicellular organisms as a community composed of a host and all its associated microorganisms. This concept has been extensively studied in the field of aquaculture, where increasing evidence has highlighted the importance of the host associated microorganisms in species fitness. Here, we focus our review on mollusc and crustacean species in which microbiota dysbiosis has recently been described in the context of various diseases, resulting in significant economic losses. Influencing the holobiont structure through the use of probiotics is a potential strategy that could improve the fitness or the robustness of cultivated species. We discuss here the possibility of developing microbiome targeted prophylactic approaches by promoting (1) methods to identify host microbial community that fosters good health status and (2) early life microbial education to favour long-term resistance to stress or disease. This review aims to inform the aquaculture industry about potential strategies in rearing practices to mitigate diseases and economic losses.

Reactive oxygen species (ROS), which are key cellular signalling molecules, are reactive chemicals containing oxygen. Cell survival or death is a critical issue in the inflammatory response. Accumulation of ROS involves ROS generation and scavenging, which determine ROS homeostasis. Understanding the roles of ROS in modulating the inflammatory response in fish is vital for helping protect fish from the damage of water pollutants in harsh environmental conditions. ROS-related key genes and signalling pathways are relatively conserved in fish but vary among different species. Recent frequent incidences of fish diseases have posed a considerable challenge to large-scale aquaculture. ROS is important in stress perception, integration of diverse stress-responsive signalling networks, and activation of animal defence mechanisms, which frequently occur during inflammation in fish. This review summarises recent studies on ROS signalling pathways during inflammation in fish. Furthermore, it examines the relationship between ROS and inflammation in fish. This review may contribute to the understanding of the underlying mechanisms by which ROS regulate inflammation in fish and provide suggestions for sustainable development in aquaculture.

One of the primary sustainability challenges in aquaculture is replacing fish meal with plant-based ingredients in aquafeeds. Plants are not optimal due to low protein content and antinutritional factors which can cause gut dysbiosis. Duckweed (Lemnaceae) is a family of aquatic plants with high protein content and has been used successfully for various types of animal feeds. In this systematic review and meta-analysis of 58 papers, we summarize the extent by which duckweed has been used in fish production including the species of fish tested, the grow-out stage of fish, and method of application. Duckweed studies spanned a total of 18 species of fish (16 freshwater and two marine) that collectively are valued at 263 billion USD annually, and comprise 28% of total aquaculture production by mass. The average experiment length was 72 days (SD 42), primarily at the fingerling life stage. Duckweed was fed to the fish through live grazing, dried, and pelleted forms with 20% inclusion as the most common formulation. The Lemna spp., dominated by L. minor, L. gibba, and unknown Lemna species, were the most commonly used for feeds. Spirodela polyrhiza was the second most common. Duckweed inclusion levels between 15% and 30% were associated with positive outcomes on fish growth and feed conversion ratio without any negative impact on survival rates. Most duckweed species, especially from Wollfiella have not been tested as a fish feed but should be explored whereas most studies focused on freshwater fishes rather than marine.