Journal of The World Aquaculture Society最新文献

This study examined the effects of fishmeal substitution with mealworm meal (MWM) in the diets of rainbow trout fingerlings (Oncorhynchus mykiss) on growth performance, flesh quality, amino acid digestibility, and digestive system histology. Five diets, which were iso-nitrogenous (average of 46.50% crude protein), iso-lipidic (average of 19.76% crude lipid), and iso-energetic (average of 15.74 kJ/g), were formulated and fed to triplicate groups of rainbow trout fingerlings (17.02 ± 1.33 g) for 90 days. Dietary treatments included one control (100% fishmeal) and four experimental diets. The experimental diets included MWM30 (150 g/kg MWM, no addition of methionine or arginine), MWM50 (250 g/kg MWM, 1 g/kg methionine, 1 g/kg arginine), MWM70 (350 g/kg MWM, 2 g/kg methionine, 2 g/kg arginine), and MWM100 (500 g/kg MWM, 4 g/kg methionine, 3 g/kg arginine). The growth performance was optimal up to the MWM70 group, while there was a significant decrease in the MWM100 group for weight gain (70.33 ± 1.13 g) and increased feed conversion ratio (1.04 ± 0.04). There was no significant difference in the proximate composition of MWM on crude protein and lipid levels in whole-body and fillet samples. Apparent digestibility coefficients were at acceptable levels, although there was a decrease in crude protein, crude lipid, and amino acid digestibility in parallel with increasing MWM levels. Histological analyses showed little adverse effects, with a significant reduction in liver vacuolization in MWM70 and MWM100 groups, and the experimental treatment did not result in severe negative effects on the formation of interstitial tissue, tubules, or glomeruli in the kidney.

Dissolved oxygen management of ponds plays a critical role in ictalurid catfish aquaculture production. If the minimum dissolved oxygen concentration falls below 3.0 mg O₂ L⁻¹, appetite is reduced, and production ultimately decreases. Although the effect of dissolved oxygen management on catfish production has been well characterized, how dissolved oxygen and aeration impact other water quality parameters is less understood. Six 0.10-ha earthen catfish ponds were stocked with 7500 (74,300 fish ha⁻¹) hybrid catfish (male Ictalurus furcatus × female I. punctatus) fingerlings averaging 39.5 g and were managed for either high (3.3 mg O₂ L⁻¹; high dissolved oxygen [HDO]) or low (1.2 mg O₂ L⁻¹; low dissolved oxygen [LDO]) minimum dissolved oxygen concentrations. Catfish in the HDO treatment grew 35% larger than their LDO counterparts, reached 456 ± 10 g after 189 days and had average net production of almost 30,000 kg ha⁻¹. Although HDO ponds ate 38% more feed on average, total (TAN) and un-ionized (NH₃) ammonia concentrations were not different between treatments. However, nitrite (NO₂⁻) and nitrate (NO₃⁻) concentrations were both significantly higher in the HDO ponds, indicating a greater proportion of ammonia was oxidized through nitrification while maintaining similar concentrations of nitrogen assimilated by phytoplankton. Higher rates of nitrification in HDO ponds are supported through higher dissolved oxygen concentrations, increased water circulation from aeration and increased suspended solids that lead to ammonia oxidation in the water column.

Soybean meal-induced enteritis (SBMIE) remains a major barrier to reducing fishmeal use in salmonid aquaculture. This study evaluated physiological and molecular responses associated with SBMIE resistance in rainbow trout (Oncorhynchus mykiss) by comparing a commercial strain (Com) and a selectively bred strain (Sel) with over two decades of selection for plant-based diet tolerance. Both strains were fed either a traditional fishmeal-based (FM) or high-soybean meal plant-based (PM) diet for 7 months. Growth performance was monitored monthly, and intestinal histology and proteomics were assessed at early (2-month) and late (7-month) timepoints. The Sel strain consistently outperformed the Com strain in final weight, weight gain and feed conversion ratio (p < 0.05), with no differences in feed intake or mortality (p > 0.05). Average weight gain was greatest in the Sel strain across diets (497.3 g on PM; 610.2 g on FM), while Com trout gained less, particularly when fed the PM diet (387.9 g on PM; 482.6 g on FM). Significant strain by diet interactions in distal intestinal histology (p < 0.05) indicated that only the Com strain developed SBMIE on the PM diet, characterized by shortened, widened villi, mucosal fold clubbing, and inflammatory infiltration. Ordinal histopathology scoring confirmed interactions for goblet cells, submucosa, lamina propria, and inflammatory cell counts (p < 0.05), confirming the SBMIE susceptibility in the Com strain. Label-free proteomics identified only 18 significantly altered proteins (FDR ≤0.05, |log₂FC| ≥1), exclusively in plasma, despite pronounced intestinal pathology in Com PM. Key plasma DEPs included upregulation of the inflammasome sensor Nlrp1 in Com PM relative to Com FM, providing molecular evidence for systemic inflammation linked to SBMIE. Exploratory gene set enrichment analysis revealed distinct functional profiles, notably heightened stress, DNA damage, and innate immune signaling (e.g., TLR pathways) in Com PM intestine, while inflammatory signatures were absent in Sel PM. These findings highlight coordinated histological and molecular adaptations underpinning SBMIE resistance in the Sel strain, demonstrate the utility of plasma proteomics for detecting systemic biomarkers like Nlrp1, and emphasizes the combined roles of diet and genetics in improving feed flexibility and sustainability in aquaculture.

Geosmin (GSM) and 2-methylisoborneol (MIB) cause objectionable off-flavors in fish produced in recirculating aquaculture systems (RAS). Remediation solutions have not been developed; therefore, a study was conducted to determine if microbial maturity limits off-flavor production. Triplicate RAS with newly established nitrification (“immature”) were compared to “mature” RAS operated continuously for 2.5 years, while growing market-size Atlantic salmon, Salmo salar. Mean waterborne GSM and MIB levels peaked at 35–40 ng/L in the immature RAS but were maintained at <13 ng/L in the mature RAS. Similar trends were reflected in salmon flesh. After 2 months, fillet GSM levels in the immature and mature RAS were 696 ± 31 and 247 ± 30 ng/kg (p = 0.001) respectively, and MIB was consistently higher in salmon from the immature RAS. The abundance of off-flavor-producing organisms was not associated with off-flavor trends, suggesting production was related to the RAS environment. Total ammonia nitrogen, nitrite-nitrogen, total suspended solids, heterotrophic bacteria count, and true color were significantly higher in the immature RAS, and nitrifier abundance was generally lower and less stable. Of these, machine learning identified true color as the most important feature affecting GSM. Ultimately, the microbially mature RAS minimized off-flavor in water and salmon flesh.

Microalgae are a valuable source of nutrients that are widely used in aquaculture to support the growth of aquatic species. This study aimed to assess the effect of replacing fishmeal with Spirulina powder (Arthrospira platensis) on the growth, survival, body coloration, and meat quality of Macrobrachium caementarius. We investigated the effects of diets containing different levels of fishmeal replaced by Spirulina powder: 0% (control), 25% (S25), 50% (S50), and 75% (S75), using 48 prawns during a 90-day experiment. Our findings indicated that the experimental diets containing Spirulina did not significantly contribute to the growth of the prawns, although the survival rate remained high. The highest (p < 0.05) dry hepatosomatic indices were observed in the prawns fed the S25 (2.85%) and S75 (2.56%) diets. We noted distinct color differences based on the diet: prawns fed the S25 exhibited a yellow-orange color, while those on the S50 and S75 diets developed a red-orange hue. Prawns of the S75 diet had significantly higher (p < 0.05) numbers (239.00/mm²), indices (4.76), and coefficients of chromatophores (95.20). Prawns fed the S50 and S75 diets showed higher protein content but lower lipid levels compared to the control diet. Our findings highlight the potential of Spirulina powder to replace fishmeal in diet formulations without compromising prawn M. caementarius performance. Diets containing 50% and 75% Spirulina powders are recommended as a fishmeal substitute. These results could contribute positively to the developing aquaculture sector for this valued species.

The goals of this research were to resolve the problems of low quantity and poor quality of eggs in cuttlefish aquaculture, and to provide empirical support for the development of formulated feeds. The impacts of different feeds on the quantity and quality of eggs laid by cuttlefish (Sepia pharaonis) were studied using three different species: Litopenaeus vannamei, Nibea albiflora, and Sillago sihama. We explored the influence of dietary composition on the quantity and quality of eggs laid. The results showed that the quantity and quality of eggs laid were significantly affected by the feed species. Compared with the feed of S. sihama and N. albiflora, the feed of L. vannamei increased the number of eggs laid by17.45% and 24.15%, the egg width by 5.05% and 5.91%, the hatching rate by 5.42% and 12.59%, and the weight of newly hatched cuttlefish by 5.05% and 5.98%, and there was no significant difference in the incubation period. The quantity and the quality (the egg width, incubation period, hatching rate, and weight of newly hatched cuttlefish) were significantly positively correlated with protein content, C18:1(n-9), C18:2, C18:3, C20:2, C20:3, arachidonic acids (AAs), eicosapentaenoic acids (EPAs), and docosahexaenoic acid (DHA) of feed. These results demonstrate that L. vannamei is the optimal feed for broodstock cuttlefish during the breeding period, and that diets rich in protein and n-3 highly unsaturated fatty acids (HUFA) can enhance their reproductive performance.

A study conducted at the University of North Carolina Wilmington examined the growth of hatchery-raised black sea bass (BSB), Centropristis striata, juveniles using recirculating aquaculture systems (RAS) technologies. Regression analysis was used to establish the relationship between fish weight and age. Subsequent growth curves were derived for hypothetical genetic generations (F1 and F2) assuming a 12.5% weight increase per generation. A model of a commercial-scale RAS facility was developed to optimize stocking, tank transfer, and harvesting schedules for each generation. The study compared biomass, harvest frequency, annual yield, and tank space efficiency (TSE) under various scenarios. Results showed that a four-stage production plan model consisting of three tanks during the final growout stage was most effective to produce F0 generation fish, yielding 35,389 lbs (16,052 kg) per cohort, 6.02 harvests, and 220,035 lbs (99,806 kg) total biomass annually, with a TSE of 89.29%. For F1 and F2 generations, similar production plan models resulted in increased biomass and TSE. Selective breeding led to an 11.8% increase in annual biomass yield for F1 fish and an additional 9.2% for F2 due to shorter inter-harvest intervals and higher TSE. Iterative testing of stocking and harvesting strategies was determined to be crucial for optimizing harvest quantity and timing in RAS BSB growout facilities.

The present study investigated the effects of replacing low-temperature fishmeal (LT FM) with graded levels of partly deshelled Antarctic krill (Euphausia superba) meal and pea protein concentrate (PDKM + PPC), PDKM alone, or whole krill meal with shells (WKM) as primary protein sources on feed pellet physical quality and sinking velocity (S_v) under varying water temperatures and salinities. Seven experimental diets were formulated and tested for S_v (at water salinities of 20‰ and 34‰ and temperatures of 4, 12, and 20°C), along with pellet length, diameter, bulk density (BD), unit density (UD), apparent porosity (AP), and Ligno pellet durability index (PDI) at four testing times (30, 60, 90, and 120 s). S_v ranged from 8.1 to 12.4 × 10⁻² ms⁻¹across all test conditions and increased curvilinearly with PDKM + PPC inclusion, but significantly (p < 0.001) decreased when PDKM or WKM fully replaced LT FM. Lower salinity and higher water temperature increased S_v; across all diets and water temperatures, S_v was 4.2% higher at 20‰ salinity than at 34‰ salinity and increased by 0.52% per 1°C rise in water temperature. While pellet diameter decreased significantly (p < 0.001) with increasing PDKM + PPC, pellet length was largely unaffected. BD ranged from 561 ± 4 to 674 ± 5 kg m⁻³, UD from 899 ± 9 to 1039 ± 15 kg m⁻³, and PDI from 81.6% to 96.2%, with PDKM + PPC diets showing higher densities and better durability. S_v correlated significantly (p < 0.001) with UD (r = 0.811), BD (r = 0.817), and PDI (r = 0.918). Based on physical pellet quality results, diets containing a mixture of PDKM + PPC can be used up to 487 g kg⁻¹ to produce a pellet with a S_v of 11.6 × 10⁻² ms⁻¹ irrespective of water salinity or water temperature.

The ability of high-value plant protein concentrates to replace fish meal and other expensive animal proteins in diets for rainbow trout depends on their available nutrient composition, cost and consistency. The aim of this study was to assess the effects of two novel corn protein products (ANDVantage™ 40Y and ANDVantage™ 50Y, The Andersons, Inc.) on the growth performance of juvenile rainbow trout. Two parallel replacement series were applied with test products included at 0%, 7.5%, 15%, 22.5%, and 30% diet dry weight replacing dietary fish meal and poultry meal on a digestible protein (DP) basis. All diets were formulated to 42% DP and 18% crude lipid, supplemented with Lys, Met, and Thr to targets of 3.8%, 1.3%, and 2.1%, respectively, and manufactured by cooking extrusion. Diets were randomly assigned to triplicate tanks of rainbow trout (Oncorhynchus mykiss, Troutlodge Inc., Sumner, WA) with a mean initial weight of 38 ± 0.7 g (mean ± SD). Fish were cultured in poly tanks (320 L) at n = 20 fish per tank in a recirculating system with a flow rate of 4–6 L min⁻¹, temperature at 15°C, and a 13:11 light:dark cycle, and fed twice daily to apparent satiation 6 days per week for 12 weeks. Including ANDVantage products at levels above 22.5% decreased growth (gram gain per fish, p < 0.0001). A significant interaction was observed for feed conversion ratio (FCR; p < 0.0001) wherein fish fed ANDVantage™ 40Y had significantly higher FCR than fish fed ANDVantage™ 50Y when fed levels above 22.5%. Optimized inclusion levels, determined by regression analysis for combined data or for each ingredient when interactive effects occurred, indicate that maximum inclusion levels for ANDVantage™ 40Y and ANDVantage™ 50Y in rainbow trout diets range from 13.5% to 21.5% depending on the performance variable assessed.

The aquaculture of Argopecten purpuratus (Peruvian scallop) is a profitable activity with positive impacts on the local economy. However, the development of biofouling on the culture lantern nets generates negative environmental impacts that affect its sustainability. A feasible option aimed at reducing the development of biofouling is to increase the frequency of lantern nets exchange. In this study, we tested whether doubling the lantern net exchange frequency in the final phase of culture reduces biofouling and, in turn, improves the growth and survival of A. purpuratus. For this purpose, in the concession of a company dedicated to the cultivation of A. purpuratus in Samanco Bay, Peru, four 10-floor lantern nets were placed at 25 organisms per floor, divided into two treatments (T1 and T2) with two replicates. One group of these (T1) was exchanged after 30 days, and another group (T2) was maintained until harvest. As a result of the lantern nets exchange, biofouling weight was reduced by 64.6%, survival improved by 10.8%, gonad weight increased by 52.5%, and adductor muscle weight increased by 62.4%, which represents an additional net income of 6582.58 US$ per ha. This study demonstrates the significant benefits of regular lantern net exchanges in mitigating biofouling and enhancing the overall yield and economic viability of A. purpuratus culture, contributing to the advancement of more sustainable aquaculture practices.