Journal of The World Aquaculture Society最新文献

US seafood retail markets are highly competitive and have evolved rapidly to supply an increased diversity of seafood products. Retail scanner data collected from grocery outlets using Universal Product Codes (UPC) reveals realistic market trends and provides deeper understanding of consumer trends. Using weekly store-based scanner data (NielsenIQ ScanTrack data) from September 2016 to August 2021, this study analyzed the product characteristics that influence seafood consumption in retail markets for general seafood as well as specific seafood categories such as finfish, crustacea, and mollusks. Explanatory variables included: price of seafood, whether the product was farm-raised, promotional share, product form (frozen or refrigerated seafood, entrée, or others), value-addition, labeling characteristics, seasons, regions, and the effect of the pandemic period. Price had a significantly inverse relationship with the quantity of general and specific seafood products sold. Being farm-raised had a positive impact on the quantity of seafood products sold in retail markets. Promotional practices also had positive effects on retail seafood sales, however with diminishing marginal returns. Among seasons, the spring season had significantly higher sales in the retail market for general seafood and finfish, but significantly lower sales for crustacean and mollusk products. Sales in the Southern region had a consistently positive effect on overall retail seafood sales. Results also indicated that retail market seafood sales were significantly higher during the COVID-19 pandemic period. Private labeling (store brands) exhibited a positive influence on seafood quantity, the same with products without any labeling information compared to products with company labels. The study highlights key market trends in US retail outlets and suggests specific marketing strategies that could be useful for seafood products.

Polychaetes are a promising intertidal resources due to their widespread distribution, considerable biomass, and high nutrition value. The nutritional profiles of two novel tropical polychaetes species (Marphysa sp. and Halla sp.) were determined. Additionally, comparing nutritional levels of polychaetes with other species and requirements of main aquatic animals, this study aimed to explore their potential as aquaculture feed ingredients. The results revealed that both polychaetes species are nutrient-rich with significant interspecific variation. Marphysa sp. showed higher protein, total essential amino acid (EAA) ratio (17.32 ± 0.46 mg/g), lipid, eicosapentaenoic acid (EPA; 10.99%), α-Linolenic acid (ALA; 1.25%), ash and energy content compared to Halla sp. (p < 0.05). Conversely, Halla sp. had a significantly higher docosahexaenoic acid (DHA; 5.68%) index compared to Marphysa sp. (DHA; 2.57%). Meanwhile, the levels of macroelements (K, Ca, Na) and trace elements (Mg, Mn, Cu) also exhibited differences in the two species. Compared with other polychaetes and aquatic feed, both Marphysa sp. and Halla sp. are promising high-quality feed ingredients, as they contain high levels of minerals, essential amino acids, and beneficial lipid profiles. This study will support the identification of alternative substitutes to meet the growing demand for aquafeed ingredients.

To improve the growth of genetically improved farmed tilapia (GIFT), the supplementation of Schizochytrium limacinum and Lactococcus lactis was sequentially optimized by a single-factor method and central composite design combined with response surface methodology (CCD-RSM) using a developed desirability function (Df) as the response value. The optimum supplementary prescriptions obtained by the single-factor method and CCD-RSM were alone 1.5% S. limacinum, alone 1 × 10⁷ CFU/g L. lactis, and 1.22% S. limacinum + 4.01 × 10⁷ CFU/g L. lactis respectively. The Df of the tilapia fed with the diets supplemented with these optimum prescriptions were 0.53, 0.54, and 0.61, respectively. The Df, weight gain rate (WGR), and feed conversion rate (FCR) of the tilapia fed with the optimum prescriptions obtained by CCD-RSM were significantly higher than those of the tilapia fed with the diets obtained by single-factor experiments and the basic diet for 28 days. Furthermore, the results of CCD-RSM can show that there were significant interactive effects between S. limacinum and L. lactis on trypsin, α-amylase, lipase, total cholesterol (TC)⁻¹ and low-density lipoprotein cholesterol (LDL-C)⁻¹, and Df, but those of single-factor method cannot.

The use of processing by-products may reduce pressure on fish stocks as well as diminish wastes and negative environmental impact. Different studies investigated fish by-products used as alternative nutritional source to conventional feedstuffs. Fish protein hydrolysates (FPH), as a protein source derived from discards of rainbow trout processing, were included in feeds and effects were evaluated on productive performances, liver status, and body composition in gilthead sea bream, Sparus aurata L., juveniles. Three groups of 170 juveniles each (initial weight 37.8 ± 0.5 g), in triplicate indoor tanks of 2 m³ volume each, were fed including FPH in L1 (7.5 g/kg) and L2 (15 g/kg) feeds in replacement of fishmeal. LC diet was used as control having fish meal and soybean meal as main protein sources. At the end of the trial (85 days), satisfactory productive performances were obtained in all the groups with similar performances. The final mean weight ranged from 76.6 to 78.0 g. The two FPH diets exhibited high palatability equal to LC. Liver histology did not differ although fat accumulation was detected in all fish. Body composition and fatty acids were similar. FPH as substitute of protein source is suitable in the feeding of gilthead sea bream juveniles.

Toll-like receptor (TLR) is one of the most important pattern recognition receptors in both invertebrate and vertebrate animals. In previous study, three different kinds of TLR cDNAs (PtToll1-3) have been cloned from Portunus trituberculatus. In this study, a novel PtToll4 cDNA sequence was identified in this crab. The PtToll4 ORF is predicted to encode 894 peptides with an initiating signal peptide, an extracellular LRRs domain, a transmembrane region, and an intracellular toll-interleukin-1 receptor domain. Based on the sequence and phylogenetic analysis, PtToll4 distinctly clustered with almost all crustacean tolls, which mostly clustered with some shrimp TLRs and Eriocheir sinensis Toll 2 (EsToll 2). The real-time quantitative polymerase chain reaction analysis showed that the transcript of PtToll4 was constitutively expressed in tissues. In hemocytes, the transcript of PtToll4 in large granulocytes is approximately threefold higher than in small granulocytes and hyalocytes. Moreover, the expression of PtToll4 could be moderately and shortly upregulated by Vibrio alginolyticus or lipopolysaccharide challenge in the primary cultured hemocytes. In HEK 293T cell model, over-expressed PtToll4 was not able to activate the mammal NF-κB, compared with a positive plasmid. In the Drosophila S2 cell model, over-expressed PtToll4 distributed mainly in cell membrane and could affect the activation of some Drosophila antimicrobial peptides promoters. The RNA interference experiment showed that the expressions of PtToll4 was significantly inhibited by its specific double-stranded RNA in the crab hemocytes and accompanied by the suppressed expressions of the anti-lipopolysaccharide factor 4 (ALF4), ALF7, hyastatin3, crustin1, and crustin3.

Because traditional barring facilities have difficulty in controlling the water surface and have low intelligence degree, a new type of intelligent electronic pulse barring facility was developed. The system established a dynamic charging and discharging model, an electric field strength calculation model, and a forward reverse rotation conduction model. The facility used a controller area network field bus to realize cooperative operation between one master machine and multiple slave machines that was suitable for fish blocking in various water areas. By using insulated gate bipolar transistors instead of thyristors, the electrode adopted an instantaneous rotational conduction mechanism that was efficient, safe, reliable, and resulted in low noise pollution. The system realized the application of the Internet of Things and an automatic fault phone alarm function in the aquaculture industry such that users could use phones or computers for real-time remote monitoring. A failure of the fish barring facility would immediately trigger an alarm, such that corresponding measures could be taken to avoid the escape of many fish and complete the unattended aquaculture industry. After multiple freshwater fish arresting tests, the load capacity of the whole machine was 0.5 Ω, and the power consumption was 0.3–2 kW; this could save 65% more electricity than traditional thyristors and had a maximum interception area of 1200 m². This has significant practical application value in improving the digitalization, automation, and intelligence level of the aquaculture industry.

This article aims to shed light on the recent sustainable transformation dynamics of the Norwegian aquaculture industry. Drawing on perspectives from the socio-technical transition studies this article investigates how this process has been shaped by a specific policy instrument known as development licenses (DL) launched in 2015. The article captures the DL as a transformative innovation policy instrument and shows how this has played a key role in steering the directionality of the technological innovations in the sector to instigate the sustainable transformation process of the industry. The article reveals that the DL has prompted the emergence of new challenged-oriented innovation systems through reorientation and reconfiguration processes. These processes specifically involved both the mobilization of actor-networks in the industry, including a functional reorientation by the key regulatory organ—the Directorate of Fisheries—and harnessing locally available pre-existing knowledge and skills—particularly in the Petro-maritime industry. The licensing scheme means that the industry is currently in the process of transition to becoming a sector based on multiple aquaculture production technologies. However, we suggest that addressing the long-term sustainable transformation imperatives of the sector will largely depend upon the ability to identify and support further development of promising niche aquaculture technologies.

Multiple-batch production is the most common farming strategy for raising channel catfish. Increased adoption of intensified alternative production practices has changed the cost structure of many catfish production practices including multiple-batch systems. Production efficiency in multiple-batch production can be enhanced by providing optimal stocking recommendations for fingerlings and carryover fish. Twelve 0.4-ha ponds were understocked with 20,782 channel catfish fingerlings (mean weight = 30 g/fish) at three different carryover biomass rates (3440; 4580; and 5702 kg/ha). Fish were fed once daily to apparent satiation with a 28% protein floating feed, and ponds were aerated with a 7.4-kW electric paddlewheel aerator. Gross, net, daily net yields, sub-marketable yields (<0.54 kg), growth (g/day), and survival were statistically similar among the three treatments, but yield of marketable fish yield (fish ≥0.54 kg) increased significantly with increased carryover biomass. The cost of production was reduced while net returns increased with increased carryover biomass. The lowest carryover biomass treatment (3440 kg/ha) had negative cash flow and net returns when sub-marketable fish were not assigned value. However, all three carryover biomass treatments attained positive annual net cash flows and net returns when sub-marketable fish were valued as revenue, the two higher carryover biomass treatments (4580 and 5702 kg/ha) outperformed the low carryover biomass treatment (3440 kg/ha). This study indicates channel catfish carryover biomass rates should be between 4580 and 5702 kg/ha to improve cost efficiency in intensively aerated, multiple-batch production systems.

Compared with common abalone, the orange-muscle abalone (Haliotis gigantea) has an enhanced ability to accumulate carotenoids. Feeding on asparagus (Gracilaria lemaneiformis) was critical for maintaining carotenoid contents in H. gigantea muscles. However, whether intestinal microbes play the role in carotenoid accumulation in different colored abalone, and the effects of different diets on intestinal microbes in abalone are unknown. In the study, the differences in intestinal microbiota between abalone with different colors and the effects of different diets on the intestinal microbiota of the abalone were analyzed. The results showed that (1) there was no significant difference in intestinal microbial community composition between the orange-muscle abalone and the common abalone, and (2) the intestinal microbial community composition of abalone fed on asparagus was significantly different from that of abalone fed on kelp (Laminaria japonica). At the genus level, the relative abundance of Psychrilyobacter in the intestinal tract of abalone fed with asparagus was significantly higher than that of kelp-fed groups. Stenotrophomonas and Vibrio were the dominant bacteria at the genus level in abalone fed with the kelp. This result excluded the role of intestinal microbes in different colored abalone and provided clues for further study of the coloration mechanism of abalone.

The early life stages of fish are critical for determining the overall productivity and sustainability of aquaculture operations. This study investigated the effects of dietary autolyzed brewer's yeast (ABY) on the growth performance and intestinal health of Nile tilapia fry (Oreochromis niloticus). A 35-day feeding trial with 480 Nile tilapia fry across 12 experimental tanks tested the effects of diets supplemented with 1, 2, and 4 g/kg of ABY, with a control diet for comparison. The results indicated that the diet which had 1 g/kg ABY supplementation (ABY1) significantly enhanced the weight gain and specific growth rate (SGR) while reducing feed conversion ratio (FCR) compared to the control diet. Intestinal gene expression analysis showed significant upregulation of immunoregulatory genes (tlr2, il10, il1β, and igm), and a tight junction gene (occludin) in the ABY1 group. Conversely, tnfα expression was significantly downregulated in the ABY1 and ABY2 groups, indicating a potential anti-inflammatory effect. Histological analysis of the mid-intestine revealed healthy morphology with no significant differences in mucosal fold length, muscularis thickness, lamina propria width, and goblet cell count among the treatment groups. The findings demonstrate that supplementing diets with ABY at 1 g/kg level enhances growth performance and modulates the intestinal immune response of Nile tilapia fry, without compromising intestinal integrity. This study offers valuable insights into using ABY as a functional feed additive to enhance Nile tilapia health and development, as well as to promote aquaculture sustainability.