Aquaculture International最新文献

The combined effects of restricted feeding rates [50–75% apparent satiation (AS) and 100% AS] and culture systems [biofloc (BFT) and traditional pond system (TP)] on the growth, production, and economics of Nile tilapia-freshwater prawn polyculture were examined in a 2 × 2 factorial feeding trial for 120 days. Each treatment was carried out in triplicate following complete randomized design. Nile tilapia fingerlings (2.09 g) and freshwater prawn post larvae (PL₂₀; 0.05 g) were stocked at an initial density ratio of 6:6 individuals/m². Lower dissolved oxygen (DO) and higher Total Ammonia Nitrogen (TAN) and nitrite concentrations were observed in BFT system. Similarly, higher levels of DO were recorded in 50–75% AS-fed group, while TAN, nitrite, nitrate, and total suspended solids (TSS) were significantly higher at 100% AS-fed group. Culture system, feeding rate, and their interactions had significant effect on final body weight (FBW) and daily growth rate (DGR) of Nile tilapia. Lower FCR in Nile tilapia was noted in both BFT system and 50–75% AS-fed group. For freshwater prawn, the highest FBW and DGR were obtained in BFT system and fed 100% AS. However, survival rates and condition factor did not differ across all treatments for both species. Higher yield for both species and more large-size tilapia were obtained when fed at 100% AS. An increase in yield and significant improvement on the size distribution of prawns were also achieved in BFT system. Although both BFT and 100% AS have led to better performance, cost and return analysis have instead revealed better profitability using TP system and feeding rate of 50–75% AS. The lower cost of production in these treatments has economically compensated for the unfavorable growth, yield, and size distribution.

Apostichopus japonicus is a significant aquaculture species in the eastern coastal regions of China. A. japonicus is a dioecious species, but it lacks secondary sexual characteristics that aid in sex identification in the sea cucumber breeding industry. An integrated comparative analysis of microRNAs and mRNA in female and male gonadal whole transcriptome datasets was conducted to identify female gonad- and male gonad-specific genes or microRNAs, particularly molecular networks between protein-coding genes and non-coding microRNAs. We identified 7613 differentially expressed genes (DEGs) and 225 differentially expressed miRNAs (DEmiRs) in total by analyzing male gonad and female gonad transcriptomes. In total, 754 DEGs were considered sex-related genes within Gene Ontology terms associated with reproductive processes or gonadal differentiation by means of GO and KEGG enrichment analysis. Among these, twenty hub genes in the female gonad (e.g., mcm5, mov10l1) and seven hub genes (e.g., tent4b, msh5) in the male gonad potentially contribute to gonadal function or reproductive processes in A. japonicus within protein–protein interaction networks. There were 140 potential miRNA-mRNA negative correlation pairs identified when predicting target genes for differentially expressed microRNA. The integrated mRNA-miRNA analysis identified 16 DEmiRs with negative regulatory relationships with key genes in the PPI network, primarily targeting five DEGs (cct2, sdr16c5, act5c, fnip1, and pla2g6). This study could provide insights into regulatory mechanisms on gonadal differentiation in A. japonicus and the molecular foundation of sexual development and reproductive biology in echinoderms.

Good water quality is a key factor to ensure the success of aquaculture. Filter-feeding clams are essential economic species in aquaculture and can produce important ecological functions through their physiological activities. To evaluate the potential of clams to improve water quality in integrated aquaculture ponds, five groups of land-based enclosure aquaculture systems were established, i.e., a swimming crab (Portunus trituberculatus)-kuruma shrimp (Marsupenaeus japonicus) bi-species culture system (referred to as PM) and four swimming crab-kuruma shrimp-razor clam (Sinonovacula constricta) tri-species culture system based on PM with different clam densities (referred to as PMS₁, PMS₂, PMS₃, and PMS₄ in order of increasing clam density). The basic physiochemical parameters, water nutrients, and heavy metals of the aquaculture water in different systems were measured during the experimental period, and the water quality was assessed and contrasted utilizing both a single-factor approach and a comprehensive water quality index (WQI) evaluation method. The results showed that water pH, contents of chlorophyll-a (Chl-a), suspended particulate matter (SPM), and total nitrogen (TN) decreased significantly with the increase of clam stocking density, while chemical oxygen demand (COD), transparency, total inorganic nitrogen (TIN), phosphate (PO₄³⁻), and total phosphorus (TP) increased significantly, and there was no significant difference in the contents of Cu²⁺ and Zn²⁺ in the water. During the aquaculture period, except for PO₄³⁻ content, the water pH, TIN, Cu²⁺, and Zn²⁺ levels in the various aquaculture systems all met the class II standard for the discharge of marine aquaculture tailwater, while COD and SPM generally fell within the class I standard. As the clam density increased, the WQI initially rose, peaking in PMS₂, but subsequently declined, attaining its lowest point in PMS₄. The above findings suggest that co-culturing razor clams at an appropriate density (50 g m⁻² under the condition of the present study) within the integrated aquaculture system combining swimming crabs and kuruma shrimp can serve as an efficient means of enhancing water quality and promoting environmental sustainability.

The adoption of innovations by hatcheries is closely linked to their preferences for those innovations. Hatchery preferences for live cold-stored Artemia affect hatchery management, production, and business performance. The objectives of this study were to assess the preferences and satisfaction levels of hatcheries and to analyze the financial performance of live cold-stored Artemia as the primary natural feed in L. vannamei hatcheries. Surveys were conducted in this study. A nonprobability sampling technique was used, with information collected through purposive sampling. A total of 18 hatcheries participated in the survey, including 11 that fully adopted live cold-stored Artemia (AC) and 7 that combined the use of live cold-stored Artemia and freshly self-hatching Artemia (AFC). The results of the classification tree analysis revealed that the predictors deemed highly influential on the full adoption of live cold-stored Artemia were technical and market support from producers, as well as the number of employees in the hatcheries. Hatcheries showed satisfaction with live cold-stored Artemia, demonstrated by a customer satisfaction index (CSI) of 81.02% and a customer loyalty index (CLI) of 71.76% in the loyal category. Financial analysis indicated that AC benefited the L. vannamei hatchery business more than the AFC, with benefit–cost ratios of 9.74 and 9.24, respectively. In addition, the IRR value of AC is 158% higher than 150% for AFC. The survival rate is a highly sensitive parameter of L. vannamei hatcheries. The L. vannamei hatcheries will suffer losses when the SR is 30% and lower, resulting in a negative NPV and IRR.

In fish, the intestine acts as a multifunctional organ, especially a single layer of epithelial cells that play a major role in osmoregulation, absorption of nutrients, and protection against invading microbes. India and other Southeast Asian countries are major carp producers, including Labeo rohita, often known as rohu. Disease outbreaks have led to a decline in aquaculture productivity. Edwardsiella tarda, a gram-negative bacteria, can cause severe intestinal diseases in fish and has zoonotic potential. Edwardsiella tarda predominantly infects the mucosal lining of the host intestine. To gain deeper insights into the molecular mechanisms following infection with E. tarda, a quantitative tandem mass tagging (TMT)-based proteomics was conducted to assess the protein expression in the rohu intestine. A total of 1839 proteins, with at least one unique peptide, were identified. Following quantitative analysis, 63 proteins were differentially abundant in response to E. tarda infection. Among differentially abundant proteins (DAPs), 35 were classified as highly abundant, while 28 were classified as low abundant in E. tarda infection. Metascape analysis was used for the gene ontology of DAPs and genes were involved in the lysosome (tinagl1, tpp1), neutrophil degranulation (bin2, nbeal2), biosynthesis of cofactors (ugt1a1, ugt2b5), extracellular matrix (ECM), and receptor interaction and basement membrane (lama4, tnca, vwa1). This study is the first to report on the rohu intestine using TMT-based proteomics after E. tarda infection. The results from the current intestinal proteome contribute to an in-depth understanding of the disease mechanisms and resilience in aquaculture.

The aim of the present study was to investigate the effects of seasons (summer and winter) on the proximate, amino acid and fatty acid compositions of gilthead sea bream fish fed with commercial diets in sea cages and earthen ponds in the Aegean Sea in Türkiye. In general, the nutrient composition of the diets met the nutritional needs of the fish. Proximate analysis of fish fillets revealed that fish reared in earthen ponds had the lowest moisture and highest lipid content in the winter season (p < 0.05). Although fillet protein contents were comparatively higher in the winter (p < 0.05), there was no significant difference between systems in the same season (p > 0.05). Growing gilthead sea bream in marine cages produced fillets with high contents of the essential fatty acids (EFA) eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). On the other hand, the 18:1n-9 and 18:3n-3 contents of fish reared in earthen ponds increased by 25.64 and 18.80% respectively, compared to those in marine cages. Fillet content of total n-3 fatty acid were comparatively higher (p < 0.05) in gilthead sea bream from marine cages, and this increase was even more evident in the winter months. The n-3/n-6 ratios of fillets were significantly high in gilthead sea bream from marine cages in the summer. The levels of the essential amino acids (EAAs) arginine and leucine were higher in fillets from both systems in the winter. On the other hand, fillet contents of lysine were higher in the summer. In general, the total EAA content of fillets was higher in fish from the sea cages in summer. EAA/NEAA ratios in both systems in summer and winter were found to be at good levels in terms of fish fillet quality. Fillet contents of EFA and EAA from both systems and seasons were found to be good for human consumption and will have positive effects on human nutrition. In conclusion, commercial diets used in feeding gilthead sea bream improved the proximate, fatty acid and amino acid compositions of fillets to a good extent. Different seasons and culture systems may affect the nutritional composition of fish fillets, especially on fillet EFA contents. Results of fillet samples in marine cages and earthen ponds in summer and winter showed that the fish were of good quality for human health. Evaluation of the results in the present study shows that that gilthead sea bream can also be successfully cultured in earthen ponds in areas unsuitable for agriculture.

Fluctuations in dissolved oxygen (DO) levels in aquaculture systems can induce hypoxia and hypercapnia, leading to physiological disruptions in fish. This study aimed to assess the effectiveness of dietary supplementation with camel whey protein hydrolysate (CWP) in mitigating the effects of hypoxia stress on physiological limits in Oreochromis niloticus. To attain this, firstly, we applied an in silico study to predict the protein–protein interaction of camel’s α-lactalbumin, lactoferrin, and lysozyme with tilapia’s NF-κB, TNF-α, IL-1β, IL-6, and IL-8 via PDBsum Generate. Then we planned for the in vivo trial; 160 obviously healthy Nile tilapia (average16.40 ± 0.40 g) were divided into four groups in four replicates for a 30-day feeding experiment. The control group (normoxic) received a basal diet without supplementation, maintaining DO levels > 90%, while the CWP group received a basal diet supplemented with 75 g/kg CWP under normoxic conditions. The hypoxic group was exposed to 20% DO levels (approximately 1.7 mg/L), and the hypoxia + CWP group received a CWP-supplemented diet under hypoxic conditions. Results exhibited a protein–protein interaction between the CWP and targeted proteins related to inflammation of the gut in Nile tilapia indicating its efficacy to protect the tissue against hypoxia stress-induced gut inflammation. Also, CWP dietary supplementation significantly alleviated hypoxia-induced impairments in weight gain, growth rate, and feed conversion ratio (FCR). Moreover, CWP consumption restored the depleted activities of intestinal lipase, trypsin, and amylase induced by hypoxia. Additionally, CWP supplementation normalized disrupted serum leptin and growth hormone levels caused by hypercapnia stress. Furthermore, CWP significantly corrected the pathological alterations, depletion of antioxidants, and increased lipid peroxidation product (MDA) in intestinal tissues induced by low DO levels. Furthermore, CWP supplementation restored the expressions of tight junction protein-coding genes (zo-1, zo-2, claudin-4, and occludin) and inhibited intestinal inflammation by modulating the MAPK/PI3K/Akt signaling pathway in hypoxic fish. In conclusion, dietary supplementation with CWP shows promise in mitigating the detrimental events of hypoxia stress on fish growth, likely through its antioxidant activity and regulation of intestinal tight junction proteins, along with its anti-inflammatory potential and significantly enhances the activities of key digestive enzymes such as amylase, lipase, and trypsin. This enzyme potentiation plays a crucial role in promoting growth in Oreochromis niloticus.

The study aims to evaluate the reproductive performance, serum biochemical indices, growth, antioxidant capacity, and immune response of Florida Red Tilapia (Oreochromis sp.) progeny reared at different salinity levels within biofloc technology (BFT) systems, focusing on egg production, fertilization rates, tolerance to oxidative stress, and offspring performance. Broodstock reared in biofloc systems (BF) were compared to those in clear water (Without biofloc, WBF) across three salinity levels (18, 28, and 36‰) over a 7-month period. The study also assessed the tolerance of fry reared in biofloc systems to direct transfer to high salinity (36‰) without prior acclimatization. A total of 216 females (initial body weight: 182 ± 1.8 g) and 72 males (initial body weight: 201 ± 0.88 g) were randomly assigned to 18 concrete tanks (2 × 6 × 1 m) to investigate the effects of BFT on spawning performance and larval survival under high-salinity conditions. The findings indicated that appropriate salinity (18‰) in BFT systems positively affected reproductive efficiency, enhanced immunological parameters, and improved growth performance, but elevated salinity levels (36‰) led to reduced reproductive success and hindered growth performance. Florida red tilapia thrive in water quality conditions that are within acceptable limits. High salinity environments led to increased dissolved oxygen but reduced pH, especially in BFT ponds. BFT improved reproductive performance, reduced spawning time, and increased egg production. It also improved hatchability, larval quality, and yolk sac absorption. The BFT broodstock showed higher levels of key proteins (total protein, albumin, and globulin) and improved immune parameters, which helped counteract the negative effects of elevated salinity and enhanced their overall health and stress tolerance. In high-salinity environments, offspring in BFT systems showed higher survival rates and growth rates. In conclusion, BFT improves the reproductive performance, growth, and immune response of Florida red tilapia under high salinity. It enhances egg production, hatchability, and larval survival, while also improving water quality and immune function, making it a sustainable solution for tilapia aquaculture in saline environments.

Ensuring a well-balanced diet is paramount for the growth and productivity of farmed fish. The interplay of nutrients, particularly essential vitamins like C and E, is crucial for supporting growth and maintaining health. This study seeks to explore the impact of varying levels of dietary vitamins C and E on the growth performance, survival rates, hematological and biochemical parameters, skeletal abnormalities, and disease resistance of hybrid grouper juveniles against Vibrio harveyi. Six experimental diets were formulated, varying in vitamin C (0, 20, and 250 mg/kg) and vitamin E (0, 50, and 800 mg/kg) contents. After a 14-week feeding trial, results revealed that vitamin C–deficient diets significantly reduced growth performance compared to other treatments. Interestingly, a high level of vitamin C without vitamin E supplementation produced growth effects similar to the control diet. Vitamin C and vitamin E supplementations influenced both hepatic vitamin C and vitamin E concentrations. Surplus supplementation of vitamin C improves immune response and disease resistance of a hybrid grouper. Skeletal abnormalities were influenced by dietary vitamin C levels. Overall, supplementation with both vitamins C and E improved growth and disease resistance in hybrid grouper juveniles. Optimal results were achieved with two specific combinations: 18.3 mg/kg of vitamin C paired with 814.8 mg/kg of vitamin E or 271.8 mg/kg of vitamin C paired with 13.4 mg/kg of vitamin E.