Reviews in Aquaculture最新文献

Nitrogenous waste is a global concern in aquatic ecosystems. In the shrimp farming system, feeding is the main input of nitrogen, which leads to the accumulation of nitrogenous waste, such as ammonia, nitrite, and nitrate. Nitrogen cycling is crucial for nitrogenous waste removal and for the stability of the aquaculture system. Under the action of different functional microorganisms, a variety of nitrogen cycling pathways can be used for the transformation and removal of nitrogenous waste. Understanding the complexity of the nitrogen cycle is necessary for improving the aquaculture environment. This review examines the many components and mechanisms involved in the nitrogen cycle in shrimp farming system, including nitrification, denitrification, anammox, heterotrophic assimilation, and autotrophic assimilation. Because of the difference in aquaculture characteristics, nitrogen cycling pathways in different shrimp culture modes are diverse. The current application of the nitrogen cycle in shrimp farming system, including the outdoor pond mode and indoor industrialized mode, was presented in combination with the requirements for dissolved oxygen (DO), organic matter, carbon–nitrogen ratio, light, and other environmental factors. Overall, nitrification, heterotrophic assimilation, autotrophic assimilation, and heterotrophic denitrification are the main nitrogen cycle processes in the shrimp culture system. According to the characteristics of aquaculture modes and microorganisms, utilizing different nitrogen cycle processes can enhance the efficiency of the nitrogen cycle, facilitate the elimination of nitrogenous waste, optimize the aquaculture water environment, and improve overall aquaculture benefits.

Salmonids, specifically Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss), are commonly farmed and their gut microbiota plays important roles for optimal growth, health, and physiology. However, differences in experimental design, technical factors and bioinformatics make it challenging to compare the results from different studies and draw general conclusions about their influence on the fish gut microbiota. For a more comprehensive understanding of the gut microbiota, we collected all the publicly accessible 16S rRNA gene sequencing data with clearly stated sample metadata from freshwater Atlantic salmon and rainbow trout intestinal contents and mucosa sequenced on the Illumina MiSeq platform. A total of 783 samples from 19 published studies were included in this meta-analysis to test the impact of the technical, environmental, and host-accociated factors. This meta-analysis revealed that all the tested factors significantly influenced the alpha and beta diversities of the gut microbiota of salmon and trout. Technical factors, especially target region and DNA extraction kit, affected the beta diversity to a larger extent, while host-associated and environmental factors, especially diet and initial fish weight, had a higher impact on the alpha diversity. Salmon had a higher alpha diversity and higher abundance of Enterococcus and Staphylococcus than trout, which had higher abundance of Weissella and Mycoplasma. The results of this meta-analysis fill in a critical knowledge gap that demonstrate technical methodologies must be standardized and factors associated with host and environment need to be accounted for in the future design of salmonid gut microbiota experiments.

Peracetic acid (PAA) has a long history as an efficacious and eco-friendly disinfectant. It was first synthesised in 1902, and since then a wide range of applications has been developed in various industries. Aquaculture is a more recent industry wherein the potential of PAA is significant. As the global demand for sustainable development increases, there has likewise been growing interest in using PAA in aquaculture as an alternative to less environmentally friendly practices. PAA has no carcinogenic risk to humans (unlike formalin), has negligible harmful by-products (unlike chlorine-based disinfectants) and with appropriate precautions, the risks of causing severe human health damage is easier to control than ozone. Fish show strong physiological recovery and adaptation to PAA, whereas susceptible life stages of pathogens are highly vulnerable, enabling a safe and efficacious disinfection of the entire culture water and not the flow-restricted disinfection by such processes as ultraviolet radiation or ozone. The effective concentration of PAA against many fish pathogens is usually below 2 mg L⁻¹, which is tolerable for most fish, and it has very low environmental risk due to rapid degradation. However, such degradation and the hydrodynamics in production-scale aquaculture systems complicate the practical use of PAA. In this review, we summarise key results of safe concentrations of PAA and its effectiveness specifically for fish farmers. We also outline major difficulties and possible solutions for practical uses of PAA. We intend to bring global attention to this compound and inspire future possibilities for its sustainable use as a water disinfectant in aquaculture.

In recent years, the production of economically important crustaceans, and decapods in inland saline areas has increased considerably. The osmoregulatory capacity of these decapods renders them culturable in wide salinity ranges, contributing to a global industry valued at billions of dollars. Therefore, gaining insights into the fundamental mechanisms that drive the adaptive capacity of crustaceans to thrive in diverse salinity ranges is essential. This comprehensive review paper unveils the pivotal adaptations of decapods that allow them to flourish in diverse salinities, ranging from freshwater to saline waters. This article discusses the molecular mechanisms of osmoregulation in decapod crustaceans with more emphasis on Litopenaeus vannammei. Moreover, the importance of maintaining an ideal osmotic balance for efficient digestion and nutrient absorption in L. vannamei is discussed. Furthermore, the effect of salinity on disease resistance in these species is explored, highlighting the need for effective disease management in aquaculture. Overall, this review explores the multifaceted factors influencing decapod crustaceans' adaptation to shifting salinities and also emphasizes the ongoing need for continued research in this domain.

Abalone is a commercially important mariculture mollusc because of its nutrient-rich value and extensive market demand. To date, over 95% of the abalone supply has been contributed by farming. Macroalgae are the natural food of abalones. However, the supply of macroalgae is unstable owing to seasonal restrictions. This limits the success of abalone farming. Therefore, formulated diets are crucial for the ongoing expansion and sustainable development of abalone culture. The most important considerations in formulated diets are the nutrient composition and commercially available feed ingredients. This review presents a comprehensive description of the nutrient requirements of abalones and the role that nutrients play in regulating abalone growth and health. The dietary proteins, lipids, carbohydrates, macroalgae sources and feed additives currently used in abalone feeds were subsequently summarised. Additionally, this review also highlights the importance of prioritizing the development of sustainable alternative sources of proteins, carbohydrates and macroalgae to meet the increasing demand for abalone feed. Based on the information provided, future directions in the knowledge of abalone nutrition and feeds are subsequently discussed, which will guide further research towards the development of well-balanced commercial feeds that enhance feed utilisation and promote abalone growth and health.

For over 70 years, aquaculture practices have relied on the same methods for biosecurity, however epidemics remain a primary limitation of global aquaculture yields with billions in revenue being lost every year due to disease. The intense nature of fish and shellfish farming necessitates the regular use of synthetic chemicals as both preventive and treatment measures, covering broodstocks to hatching and continuing through all stages of rearing. This practice, however, results in the contamination of rearing environments with persistent xenobiotics. A specific drawback in this foundational strategy for aquaculture biosecurity is highlighted in the current review: the consistent use of a water-soluble polymer polyvinylpyrrolidone (PVP) across most, if not all, stages of rearing aquacultural livestock. PVP is used intensively within aquaculture practices as it is a ubiquitous additive within commercially available germicidal, prophylactic, and therapeutic products applied to control and prevent disease outbreaks within aquacultural farms. As a polymer, PVP is synthetic and biodegradation-resistant, and has recently been described as an emerging contaminant of freshwater ecosystems. It is well documented that other persistent, synthetic polymer pollutants such as microplastics, reduce the fecundity, growth, and significantly deplete immune function in commercially important aquatic species. Despite this, intentionally added persistent soluble polymers, such as PVP, have not been considered in the context of aquaculture productivity. This review explores the potential impact of PVP on fish and shellfish highlighting the need for aquaculture to adopt sustainable chemical practices, drawing inspiration from advancements in nanotechnology applied within human medicines to address biosecurity protocol deficiencies.