Journal of The World Aquaculture Society最新文献

The culture of seahorses Hippocampus erectus in captivity represents a window of opportunity for the diversification of the aquaculture activity in the ornamental industry. In this study, we have constructed a bioeconomic model to evaluate the optimal harvest time (OHT) over a culture period of 562 days. The bioeconomic model was integrated with three submodels: biological, technological, and economic. Three different mortality rates were used for different periods in culture, registering a higher survival in the period from 0 to 60 days with a rate of 53.4%. The sensitivity analysis showed that the mortality rate in this period was the parameter with the greatest influence on the benefits. The Von Bertalanffy growth model was indicated to describe the growth of H. erectus given its statistical significance using Theil's inequality coefficient, registering parameters of (L∞ = 141.62 mm) and (k = 0.0049 month-1). The bioeconomic model determined the OHT in the 4th month of culture, the time when the maximum profit is recorded. It is concluded that the culture presents challenges to be addressed although the bioeconomic model allows for demonstrating the OHT.

We aimed to investigate the effects of Bacillus cereus YB1 on the growth, intestinal digestive enzyme activity, liver antioxidant enzyme activity, and intestinal tissue structure of juvenile black rockfish (Sebastes schlegelii). A 50-day feeding experiment was conducted. Feeding was conducted in four diet groups: control group with no YB1 supplement in diet and three treatment groups E-L, E-M, and E-H containing 10⁵, 10⁶, and 10⁷ CFU/g YB1, respectively. The results revealed that the weight gain and specific growth rate of juvenile fish significantly increased, while the feed coefficient was reduced in all three diet treatment groups. This indicated that the growth of black rockfish was significantly and positively affected by YB1 feeding. Enzyme activity in the intestinal tract was not significantly affected by YB1. However, the activity of protease, amylase, and lipase increased because of YB1 treatment, except for the proteases in the E-M diet group. Meanwhile, no significant differences were recorded in the activities of the antioxidant enzymes in liver, but the level of catalase, superoxide dismutase, and malondialdehyde activities in treatments shows a better performance compared with the control in overall perspective. Furthermore, the structural features of the intestine (i.e., number of intestinal villi, length of gut villi, and thickness of muscularis) was significantly elevated with the inclusion of B. cereus YB1 in the diet. These results reveal that dietary supplementation of B. cereus YB1 is beneficial to the boosting of enzymatic activities and structure of intestinal tissue as well as the antioxidative ability of liver tissue. Such findings suggest that fish growth would be improved under YB1 feeding conditions.

Replicating maternal care and incubating octopus embryos artificially is advantageous to improve access to embryonic stages, split and share broods, and reduce the required space to culture large quantities of embryos. However, without female care and adequate rearing systems, the risk of bacterial and fungal infections can be high. This study evaluated the potential effects of low-concentration sodium hypochlorite (NaOCl) as a disinfectant on embryonic survival, hatchling survival, and growth. Embryos of a holobenthic octopus, Amphioctopus fangsiao, and of a merobenthic octopus, Octopus sinensis, were disinfected with 0.004% NaOCl for 3 min either once at the start (IB), at the start and halfway point (RB), and without disinfection (control). Survival of A. fangsiao embryos differed among treatments initially, but the final number of hatchings did not differ among treatments. No differences in the final survival for O. sinensis embryos were observed among the three treatments. Wet weight and growth for A. fangsiao juveniles did not differ among treatments at any point. In contrast, initial and final dry weight for O. sinensis paralarvae from the control treatment were heavier compared to the IB and RB treatments. These results suggest that NaOCl used as disinfectant has a species-specific effect on early hatchlings depending on the octopus life history.

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.