Journal of The World Aquaculture Society最新文献

Organic aquaculture aims to provide sustainable aquatic products, and utilizing innovative aquafeeds with less fish meal is crucial. This study evaluated the impact of a cost-effective and environmentally friendly diet (51% replacement with plant/animal protein sources like fermented soy, pea, krill, squid, and yeast meals) on gilthead seabream (Sparus aurata) growth, health, and welfare using a multiparametric approach (growth, swimming activity, blood health, and welfare indicators). The innovative diet showed no adverse effects on growth performance and survival. Hematological and biochemical blood indicators demonstrated minimal alterations, with only lactate levels increasing, suggesting no compromise in overall welfare. Immune features indicated a potentially stronger innate immune response in fish fed the innovative diet, as shown by higher levels of total proteins, alpha 1, and beta 1. Finally, a slight difference was observed in swimming activity between diets, but primarily occurred at the end of the day. A comprehensive multiparametric analysis and multi-criteria decision analysis indicated better global welfare and health status with the innovative diet compared to the control. While the innovative diet showed promising results for gilthead seabream organic aquaculture, further long-term investigations are necessary to explore the underlying causes of the observed immune parameter changes.

Fishmeal (FM) is still believed to be the gold standard protein source, especially for high-value aquaculture species such as salmon. However, due to supply and price fluctuations, coupled with environmental issues in FM production, FM is no longer a sustainable source from economic and environmental perspectives. Recently, high-protein corn co-products, such as high-protein distiller's dried grains (HP-DDG) and corn-fermented protein (CFP) have attracted much attention as alternative protein ingredients. Therefore, a 12-week feeding trial was carried out to assess a CFP product on growth performance, feed utilization, antioxidant and non-specific immune responses, and intestinal histopathology as an FM replacer in the diets of Atlantic salmon parr, Salmo salar. Five isonitrogenous (51% crude protein) and isocaloric (22.3 MJ kg⁻¹) diets were formulated to substitute 0% (CFP₀), 25% (CFP₂₅), 50% (CFP₅₀), 75% (CFP₇₅), and 100% (CFP₁₀₀) of FM with a corresponding amount of CFP. The experimental diets were fed to satiation, three times daily, to quadruplicate groups of Atlantic salmon parr (11.6 ± 0.06 g). At the end of the 12-week feeding trial, the final weight, weight gain, and survival of fish did not significantly differ between treatment groups. However, in fish fed CFP100, both the feed conversion ratio (FCR) and the protein efficiency ratio (PER) exhibited significant differences in comparison with those of fish fed other treatments, with FCR being significantly higher and PER being significantly lower. Quadratic regressions of PER and FCR against the dietary CFP inclusion levels suggest that the optimal substitution level was between 18.6% and 25%. Parameters related to antioxidant and non-specific immune responses were not significantly impacted by the dietary treatment except for lysozyme activity. Lysozyme activity exhibited a significant increase in fish fed CFP₂₅ in contrast to the fish fed CFP₇₅. With respect to distal intestinal morphology, fish fed CFP₀ and CFP₂₅ exhibited significantly higher fold height, while fish fed CFP₅₀ showed a reduction in fold height. The mean score of evaluated histopathology features was not significantly influenced by the dietary CFP levels. In conclusion, based on the results of the analysis of variance (ANOVA), replacing 50% of FM with CFP can be implemented without any detrimental effects on growth performance, feed utilization, non-specific immunity, and intestinal health during the parr phase of Atlantic salmon production.

Maintaining a healthy intestine is essential for growth and host defense mechanisms of farmed fish, particularly those densely stocked. In this context, maintaining a healthy intestinal microbiota for proper digestion, absorption, and integrity of the mucosa is of utmost importance. Nano-form (SeNPs)-enriched-Pediastrum boryanum (Turpin) exhibits antimicrobial, antioxidant, and antitumor properties. Therefore, SeNPs are valuable nutritional supplements for farmed aquatic animals. Algogenic Se nanoparticles (SeNPs, 79.26 nm) were synthesized from the green microalga Pediastrum boryanum. A Nile tilapia (Oreochromis niloticus) basal diet was blended with 0.75 or 1.5 mg/kg dry feed of the SeNPs for and fed for 8 weeks. Comprehensive arrays of intestinal biomarker-related parameters were investigated. Supplementation with SeNPs, particularly at a 1.5 mg/kg diet, improved growth performance, amylase and lipase activity, serotonin metabolite level, and intestinal morphometry. In addition, SeNPs supplementation suppressed serotonin levels. SeNPs at a 1.5 mg/kg diet were observed to be the optimal dose, as they showed better results concerning the increase in beneficial microbes and decrease in pathogenic microbes, demonstrating the potential role of SeNPs in growth improvement and enhanced intestinal functions. The sum of our data underscores the benefits of supplementing Nile tilapia feed with SeNPs to promote the growth and profitability of aquaculture.

This study investigates the influence of dietary inulin on the growth and health of juvenile shrimp Litopenaeus vannamei over an 8-week trial, focusing on growth, health, and metabolic impacts because of diet variation. A total of 240 shrimp with an initial mean weight of 0.26 ± 0.01 g were distributed across 12 recirculating tanks and assigned diets with varying inulin concentrations: 0% (Control), 0.5% (T1), 1.0% (T2) and 1.5% (T3). Results indicated that the 1.0% inulin diet resulted in the highest specific growth rate, weight gain, and survival rate. An increase in antioxidative and immune enzyme activities suggested improved health conditions at optimal inulin levels, evidenced by the reduction of malondialdehyde content and potentiation of enzymes like superoxide dismutase and lysozyme. Microbiome analysis via 16S rRNA sequencing showed a significant shift in gut bacterial populations, with an increase in beneficial bacteria such as Xanthomarina and a reduction in pathogenic Vibrio and Flavobacteria in inulin-supplemented groups. Higher dietary inulin increased gut microflora diversity significantly in the T2 group. Metabolomic analysis showed distinct pathway enrichment and differential metabolite regulation, linking inulin intake to significant alterations in lipid metabolism, including pathways like bile secretion, arachidonic acid metabolism, steroid hormone biosynthesis, and ABC transporters. Furthermore, correlation and KEGG enrichment analyses revealed intricate interactions within the shrimp metabolic network, pointing to compensatory and regulatory mechanisms in response to inulin supplementation. In conclusion, dietary inulin substantially improves the health and growth of L. vannamei, likely by modulating gut microbiota and metabolic pathways. This study highlights the potential of inulin as a significant dietary supplement for enhancing shrimp aquaculture efficacy.

The US DOE/ARPA-E MARINER program funded a 4-year project to determine an optimal way to grow kelps in large, nearshore and offshore arrays for the eventual purpose of biofuel production with the goal of keeping the cost below $80 USD per dry metric ton of kelp. This project specifically looked at how Saccharina latissima can be grown in the Gulf of Alaska to reach that goal. There were three major aspects of the research: (1) optimize nursery production and seeding lines for outplanting; (2) design an economical, modular outplanting structure; and (3) develop methods to efficiently harvest the product. Farm designs were based on catenary structures and the use of spreader bars with variable spacing of grow-lines and line types. The spacing of the grow-lines makes a difference in the yield. Grow-line spacing of ≥1.5 m showed about a 50% increase in production (kg m⁻¹). There was no statistical difference in the growth of Saccharina latissima whether in the middle or the outside of the array, but the line type and perhaps line thickness can make a difference in yield. Sagging caused by the weight of the mature fronds resulted in lower growth at depth. Various harvesting approaches for mature kelps were tested by collaborating farmers. One promising innovation is the use of large bags with mesh for temporarily holding the freshly harvested fronds in seawater. Although the weight of the fronds on the grow-lines causes the lines to sink, the bags packed with the harvested fronds float, allowing for temporary storage before loading to a vessel heading to port and processing. Another advance in harvesting is a specially built harvest vessel, the Harvest Buddy, allowing a more mechanized and faster way to harvest. A techno-economic assessment (TEA) using our data has pointed to solutions to reach the goal of $80 USD per dry metric ton of kelp.

Feed conversion efficiency (FCE) is an important determinant of profitability in catfish production. Understanding factors affecting FCE at a physiological level could lead to improvement of FCE at production scale. The effect of sex, family, and size grading within family on juvenile channel catfish (Ictalurus punctatus) growth, feed consumption, feed conversion, visceral fat accumulation, and weight loss during feed deprivation was determined. In Trial 1, fingerlings from five channel catfish families were graded by weight into small, large, and random mixed-size groups, fed for 8 weeks, subjected to 2 weeks of feed deprivation, and then euthanized to determine sex. Family had a significant effect on fish growth, feed consumption, FCE, and percent weight loss during feed deprivation. Large fish had faster growth, better FCE, and lower percent weight gain than small fish from the same family. Mixed-sized fish were generally intermediate for all measured traits. In Trial 2, all-male, all-female, and mixed-sex groups of channel catfish fingerlings were subjected to the same feeding regime and then euthanized to confirm sex and weigh visceral fat. Males had a higher percent weight gain, better feed conversion, and less visceral fat than females; mixed-sex fish were generally intermediate between all-male and all-female groups. FCE was positively correlated with visceral fat percentage in the all-female treatment (i.e., fatter fish had poor feed conversion), but not in the all-male treatment. Feed conversion and weight loss during feed deprivation were generally not correlated in either trial. This is the first report that male channel catfish convert feed more efficiently than females. Future studies should investigate the relationship between fat and feed conversion in channel catfish.

Creatures grown on the island are more susceptible to genetic vulnerabilities because of their isolated nature and often limited genetic diversity. Understanding the genetic structure of these populations is crucial for effective conservation strategies, especially for the species that are commonly found in aquaculture and may inhabit islands. Bufo gargarizans and Pelophylax nigromaculatus were distributed in the Chongming Islands of Shanghai, China. We analyzed mitochondrial DNA cytochrome b (cytb) and D-loop sequences of the populations of the two species across three Chongming islands to investigate genetic diversity, phylogenetics, and infer historical demography, which indicated a lower genetic diversity in island populations compared with their mainland counterparts, reflecting a heightened vulnerability to environmental perturbations and potential extinction risks. Noticeably, a more interlaced genetic pattern was determined in P. nigromaculatus than in B. gargarizans, which was probably attributed to the differences in species' dispersal capabilities among the populations of islands and the mainland. Hence, the genetic analyses propose targeted recommendations for in situ conservation and aquaculture management.

The aquaculture industry plays a crucial role in global food production and is expected to expand in response to the increasing demand for aquatic products. To sustain this growth, aquaculturists must develop new strategies and improve existing practices to address various challenges. In Africa, the sustainable development of aquaculture could be achieved not only by intensifying and integrating breeding techniques for species like Tilapia and Catfish but also by developing and domesticating other promising species with high aquaculture potential. Identifying and understanding these species is vital for overcoming these challenges. Heterotis niloticus is one such valuable species for aquaculture in Africa, offering several advantages including its air-breathing capability, high market value, excellent meat quality, omnivorous diet, resilience to stress, ability to survive in low-oxygen water, and consumer acceptance. In captivity, it has shown significant growth, with individual mean body mass reaching 3 to 5 kg in 12 months. These findings highlight the potential of Heterotis niloticus to enhance aquaculture production, not only in Africa but also globally. However, challenges remain, such as high mortality during early life stages, the determination of its nutritional needs at various ontogenetic stages, and the development of efficient breeding practices. Further research is required in areas like nutrition, physiology, breeding technology, genetics, economics, and environmental impact to optimize the culture of this species.

This study investigates the efficacy of acid-insoluble ash (AIA) as an endogenous digestibility marker in commercial aquaculture ingredients and feeds. AIA is a naturally occurring, low-cost alternative to external markers such as chromic oxide and yttrium oxide. External markers are often impractical in the production of small batches of feed manufactured under commercial settings due to cost and logistical constraints. This manuscript is the first of its kind to quantify the AIA content of 18 commercial aquaculture feeds and 27 commercial ingredients from diverse origins, as well as the recuperation rate of pure AIA. Samples were acquired from various national and international sources based on currently available stock; all samples were analyzed in quadruplets for statistical analysis. Results indicated significant variation in AIA levels across different ingredient categories (p < 0.05), with marine-based meals and rendered animal meals exhibiting the highest AIA concentrations (up to 25.8% and 5.0%, respectively), while vegetable meals displayed the lowest AIA content (up to 0.2%). Shrimp and crab meals had particularly high AIA levels due to their mineral-rich exoskeletons (4.7% and 25.8%, respectively), and meals that had undergone certain commercial processing to increase the meal quality had lower AIA content than their regular counterparts (avian: 2.9% for high quality and 4.4% for regular quality; meat: 0.13% for high quality and 0.8% for regular quality). Additionally, a limit of quantification (LOQ) was determined to define the confidence range of the utilized AIA protocol. This study highlights the importance of considering diet composition and ingredient origin in diet formulation to ensure consistent nutritional outcomes. Furthermore, we demonstrate that a wide range of commercial diets contain a quantifiable amount of AIA. The findings suggest that AIA can serve as a reliable and cost-effective marker for in-vivo digestibility studies, aiding feed manufacturers and farm managers in optimizing production performance by rapidly assessing feed quality.

Automatic feeders are revolutionizing aquaculture by enabling precise and controlled feeding regimens that optimize growth, reduce feed waste, and enhance the overall efficiency of farming operations. Demand feeders provide some similar benefits but with feeding tailored to fish appetites and, in some cases, feed dispersal without electricity. This review explores the evolution, technological advancements, and applications of these feeders with a survey of recent research. It looks at common feeder designs and compares the pros and cons of five automatic feeder configurations in commercial use today. The article contrasts feeders and feed sizes for farmed species in different life stages and facilities, from hatcheries to ponds and offshore cages. It discusses the importance of species-tailored feeding strategies as well as impacts on fish behavior and health, nutrient delivery, and environmental sustainability. Incorporating sensors and on-site computing enables optimization in feeding algorithms that feeders then implement precisely and reliably. The review compiles results from multiple studies comparing growth rate, weight, and feed conversion ratio (FCR) outcomes from automatic feeders and demand feeders versus traditional hand-feeding regimens. The integration of feeders with real-time monitoring and data analytics is also discussed, highlighting future directions for research and adoption across the industry.