Journal of The World Aquaculture Society最新文献

The main cost in aquaculture production is feed, so management practices and feeding strategies aim to optimize both feed intake and efficiency. This study aimed to evaluate the growth performance of beluga, Huso huso, affected by periodic changes in dietary protein sources and hence identify possible innovative feeding strategies toward more efficient use of dietary protein. This study was designed with two experimental diets, namely fish meal (diet A) and plant protein blend (diet B) (protein 40%, fat 16%), which were used in different food schedules for feeding beluga (initial weight 82.08 ± 4.1 g) during 8 weeks. The experimental treatments included: continuously feeding a fish meal diet (A); continuously feeding a plant protein diet (B); alternating between diet A in the morning and diet B in the afternoon (A am/B pm); alternating between diet B in the morning and diet A in the afternoon (B am/A pm); and alternating between diet A for one day and diet B for one day (1A/1B). At the end of the eight-week trial, superior growth performance and feed utilization were respectively observed in fish receiving A, Bam/Apm, and Aam/Bpm diets compared with the remaining treatments. The specific activity of trypsin and chymotrypsin was significantly high in fish fed Aam/Bpm and Bam/Apm. Feeding the fish-meal-based diet (A) continuously, led to decreased protein and increased fat deposition in the carcass. Among the mixed feeding schedules, the highest cost-saving was recorded with the Aam/Bpm and Bam/Apm schedules. Based on economic analysis, applying Aam/Bpm and Bam/Apm schedules led to the reduced cost of beluga production compared with the other treatments. Therefore, the optimal feeding schedules for beluga are Aam/Bpm and Bam/Apm, which should be used as a practical feeding guideline for H. huso production.

Dietary supplementation with synthetic β-carotene was investigated in this study to assess its impact on gonad development, antioxidant status, color parameters, and carotenoid composition in adult female swimming crab (Portunus trituberculatus). Four diets, designated as Diet 1 to 4, were formulated to contain 3.07, 53.78, 103.23, and 205.22 mg/kg dry diets of synthetic β-carotene. The findings revealed the following: (1) No significant differences in body weights or feed utilization were observed, indicating that β-carotene did not significantly enhance the growth of adult P. trituberculatus. (2) The inclusion of 50–100 mg/kg β-carotene in the diets led to improvements in antioxidant capacity indicators (T-AOC, MDA) and immune-related parameters (AKP, ACP) in both hepatopancreas and hemolymph. (3) Notably, the redness of ovaries and hepatopancreas increased significantly with higher dietary β-carotene supplementation for color enhancement. In conclusion, incorporating β-carotene into the diet enhanced the antioxidative capability, nonspecific immunity, and tissue carotenoid contents in adult female P. trituberculatus, and the optimal level of dietary synthetic β-carotene supplementation for adult female P. trituberculatus was suggested to be around 100 mg/kg.

This study investigated the disparities in soil characteristics and pathogenic bacteria prevalence between shrimp ponds affected by acute hepatopancreatic necrosis disease (AHPND) and unaffected ponds, alongside examining the spatial distribution of soil attributes in flat-oriented pond soil strata. Using Pearson correlation and logistic regression analyses, relationships among variables and indicators associated with AHPND prevalence were discerned, leading to the formulation of a predictive model for AHPND occurrence. Soil samples were collected from distinct locations and depths within ponds across three southern provinces of Thailand's Andaman Seaboard. The analysis revealed significantly higher concentrations of several variables, including SOD, TIC, NO₂⁻-N, Ca, Mn, Cu, Zn, and specified Vibrio strains, in AHPND-afflicted ponds, especially at 0–5 cm depth. A prominent differentiation was the escalated concentration of easily decomposable organic matter (EDOM) within infected ponds, implicating potential soil and water quality deterioration alongside heightened shrimp susceptibility to AHPND. Correlational analysis showed links between bacterial densities and organic matter groupings, trace elements, exchangeable bases, and soil pH, in AHPND-infected ponds. The logistic regression model encapsulated three soil variables (TOC, Mg, and Mn) and one pathogen variable (V. parahaemolyticus) and furnished an equation to estimate the log (odds) of AHPND occurrence, facilitating better understanding and potential forecasting of AHPND prevalence in shrimp cultivation environments.

An apparent sexual dimorphism, such as growth rate and immunocompetence, is observed in the Chinese soft-shelled turtle (Pelodiscus sinensis). The identification of sex-related markers and candidate genes holds significance for the sex-controlled breeding of P. sinensis. In this study, through an integration of whole-genome resequencing and Sanger sequencing, 21 female-specific single nucleotide polymorphisms (SNPs) were identified. Based on these SNPs, the rapid and cost-effective molecular methodologies for genetic sex identification in P. sinensis were established. Of note, 19 validated SNPs are located within the zinc and ring finger 3 (ZNRF3) gene, which has been reported to be testis-determining in mammals. Cloning of the ZNRF3 gene from P. sinensis (PsZNRF3) and analysis of its expression profile in tissues and in response to sex steroid hormone treatment demonstrated exhibiting a female-biased expression pattern. These findings not only provide molecular markers for sex-controlled breeding in P. sinensis but also open up a solid basis for revealing the sex-determination mechanism of this species.

Projected growth in insect production as alternative feedstuffs will yield novel by-products that are potentially valuable for aquafeed applications. We analyzed the nutrient composition of three by-products occurring from black soldier fly larvae production (exuvia, cocoon, imago) and the bioavailability of key nutrients for Pacific Whiteleg shrimp (Litopenaeus vannamei). Protein accounted for 317 g kg⁻¹ in exuviae, 433 g kg⁻¹ in cocoons, and up to 521 g kg⁻¹ in adult flies (imagines). Considerable amounts of essential amino acids were detected in imago meal, which significantly matched the ideal dietary amino acid composition for penaeid shrimp (r² = 0.66, p = 0.0076). Exuviae and cocoons contained moderate amounts of lipids (64–140 g kg⁻¹), while imagines comprised 356 g kg⁻¹ total lipid. Saturated fatty acids predominated in all insect materials (47%–83% of total fatty acids). Chitin concentration was highest in cocoons and exuviae (154 and 139 g kg⁻¹) and low in imagines (51 g kg⁻¹). A feeding trial with shrimp, L vannamei, revealed apparent digestibility coefficients of 20%–59% for protein, 24%–54% for energy, 25%–49% for carbon, and 27%–68% for copper. Defatting of imago meal increased the digestibility of protein, energy, and carbon by 77%, 64%, and 61%, respectively. Defatted imago meal can serve as a protein supplement for shrimp diets.

This study investigated the production performance, household fish consumption, and commercial feasibility of prawn–carp–mola mixed gher farming system. Three treatments with different species compositions were compared: prawn + rohu, prawn + mola, and prawn + rohu + mola, each having different stocking densities. The results indicated that the integration of mola improved the utilization of feed protein by prawns. However, mola inclusion did not significantly affect the growth of prawn and rohu or the production system's cost. Mola inclusion led to a significant increase in the gross production, household consumption, and sale of mola, prawn, and rohu. It also increased gross returns, income above variable cost, and net returns to land, family labor, and management. In addition, the inclusion of mola significantly increased household consumption by increasing the intake of nutrient-rich mola and overall fish consumption. This improvement in food consumption contributed to ensuring the nutritional requirements and food security of impoverished rural farmers, especially women and children. Consequently, the integration of small fish mola in prawn–carp gher farming systems is recommended as a beneficial practice for wider adoption, effectively addressing household nutrition security at the rural level and improving the livelihoods of farmers.

Striped catfish are one of the main aquaculture species in Asia. However, the low level of omega-3 fatty acids in its body makes this species less attractive compared with marine fish. This study aimed to investigate the effect of different oils on growth performance, body composition, and fatty acids in striped catfish juveniles. A basal diet (T0) was formulated to contain no oil, while four other diets (T1, T2, T3, and T4) were supplemented at 4% with different oils, including salmon oil (SALO), soybean oil (SBO), linseed oil (LSO), and rapeseed oil (RSO). Catfish juveniles with initial body weight (23–24 g/fish) were randomly stocked in 500-L fiberglass tanks, divided into five treatments, three replicates for each, and fed the experimental diets for 60 days. Results from this study revealed that fish fed the LSO-supplemented diet had significantly (p < 0.05) improved whole body omega-3 (alpha-linoleic acid, 18:3n3) fatty acid levels (7.86%), total n-3 fatty acids (9.12%), and higher growth than those fed the other diets. In conclusion, the findings suggest that linseed oil can be used to improve growth, omega-3 fatty acid, C18:3–3 (ALA), and total n-3 PUFA deposition in the whole body of striped catfish juveniles.

Compound plant extracts (CPE) are beneficial for aquatic animals on growth performance and antioxidant capacity. A 56-day experiment was conducted to investigate its positive effect on rice field eel. The fish were fed a commercial diet and supplementing CPE (mainly containing eucommia polysaccharides, reducing sugar) at 0, 0.8, 1.6, 2.4, and 3.2 g/kg. Results showed that dietary CPE significantly increased weight gain and specific growth rate (p < 0.05). Liver lipid content in 1.6 and 3.2 g/kg groups was significantly lower than in 0.8 and 2.4 g/kg groups (p < 0.05). Muscle lipid content in 0.8, 2.4, and 3.2 g/kg CPE groups was significantly lower than in control (p < 0.05). Meanwhile, intestinal digestive enzymatic activities in the 3.2 g/kg CPE group were the highest in comparison to all other groups (p < 0.05). Dietary CPE enhanced the antioxidant activities of serum and intestine (p < 0.05). Compared with the control, intestinal fold thickness in CPE groups was significantly increased (p < 0.05). Furthermore, dietary CPE reduced the degree of liver steatosis and the number of lipid droplet vacuoles. This study indicated that dietary CPE was beneficial to growth performance, antioxidant capacity, liver, and intestinal histology. Supplementation with 1.6–3.2 g/kg CPE is optimal for this eel species.

Promoting the productivity and environmental sustainability of aquaculture is critical in ensuring its healthy development. This study assesses freshwater aquaculture's technical efficiency and ecological efficiency in China's 19 inland provinces from 2008 to 2019, aiming to reveal its productivity and environmental sustainability status. We employ the three-stage Data Envelopment Analysis-CCR (T-DEA-CCR) and three-stage Slack-Based Measure-DEA (T-SBM-DEA) methods to explore the technical efficiency and the ecological efficiency while accounting for environmental conditions and random errors. The average technical efficiency and ecological efficiency during 2008–2019 are 0.857 and 0.702, respectively, indicating substantial scope for enhancing the productivity and environmental sustainability of China's inland aquaculture. We further investigate the regional development using the club convergence, finding that the provincial-level technical efficiencies have already achieved population convergence while the ecological efficiencies diverge into two clubs, suggesting that Chinese freshwater aquaculture's productivity and environmental sustainability have different development pathways. Acknowledging the pivotal roles of environmental protection and growers' training in aquaculture's productivity and environmental sustainability, policymakers may institute funding and recognition to foster the adoption of innovative, environmentally responsible practices by operators.

The present research evaluates the performance of the Nile tilapia (Oreochromis niloticus) (initial weight 11.5 ± 0.07 g) with biofloc technology. For this purpose, spent grains (malted barley) from the brewing industry after aerobic fermentation were used, as both a carbon source (suspended solids) and partial substitute for the diets at 0, 10, 20, 30, and 40% levels (settleable solids). The partial 20% substitution of the diet did not have significant effects on the biological parameters: final body weight, weight gained, average body weight, specific growth rate, daily growth index, condition factor, feed conversion ratio, protein efficiency rate, and viscerosomatic and hepatosomatic indices. However, the dietary substitution showed a significant effect on the final biofloc chemical composition. Nitrogen compounds, NH₄⁺, NO₂⁻, and NO₃⁻, were adequate for tilapia cultivation in all the treatments. No clear effect of partial dietary substitution was observed on meat quality parameters: pH, color, water holding capacity, and amino acid and fatty acid profile of fillet. The results suggest that a 20% substitution of the diet for malted barley is suitable for satisfactory biological parameters and Nile tilapia fillet quality.