Aquaculture International最新文献

Super-intensive shrimp culture has been proven to increase shrimp production in ponds, but it has consequences for the waste generated, which is quite large, up to 10–20 tons/cycle. This great potential is expected to benefit the growth of mangroves as coastal ecosystem plants. This study evaluated mangrove growth performance using the ratio between super-intensive pond (SIP) solid waste and coastal soil. The study was set using a completely randomized design using four treatments, each with three replications, namely treatment, A = 25% SIP solid waste + 75% coastal soil, B = 50% SIP solid waste + 50% coastal soil, C = 75% SIP solid waste + 25% coastal soil, and D = 100% SIP solid waste. Each treatment planted mangrove seeds with a spacing of 50 × 60 cm², and 30 trees were obtained per experimental unit. The results obtained showed that the treatments tested had a significant effect (P < 0.05) on plant height growth, while stem diameter, number of leaves, plant sturdiness, and survival rate of mangrove did not significantly different results (P > 0.05) for all treatments. The 100% SIP solid waste treatment produced the highest plant height of 16.2 cm, good plant sturdiness, and achieved 100% survival of mangrove seedlings across all treatments. The use of shrimp pond solid waste as mangrove seedling media has an impact on reducing waste in coastal areas, maintaining the aquaculture environment, developing sustainable aquaculture, and supporting the enhancement of mangrove restoration.

The aquaculture industry faces significant challenges in maintaining fish production due to the high concentrations of ammonia, which needs to be addressed in an environmentally sound and economically viable approach. The present study explores the use of cheap, readily available, and environmentally friendly sugarcane bagasse and luffa sponge fiber as porous lignocellulosic biomass for biotransforming ammonia in experimental aquaponics water. A 45-day experiment was set up, with Pangasianodon hypophthalmus as the experimental fish in tanks containing aquaponics water. The study consists of a control (CON) and three treatments, viz. BAF (Bagasse), LuF (Luffa fiber), and MixF (Bagasse + Luffa fiber). Weekly spiking of ammonia at different doses was carried out (2, 2.5, 3, 5, and 10 mg L⁻¹). Porous lignocellulose reduced ammonia, resulting in lower stress and better growth through two mechanisms, viz., substrate for the autotrophic nitrifiers to perform nitrification shown by the increase in nitrite with the decrease in ammonia and the assimilation of ammonia by the aerobic heterotrophs using the lignocellulose as a carbon source, which is indicated by the increase in the colony-forming units in terms of biofloc in the water. The result showed the ammonia removal efficiency to be highest in MixF with 67.75% ± 3.26 after 96 h of spiking 10 mg L⁻¹ TAN, followed by BAF and LuF, while the control group was ineffective at 10 mg L⁻¹ TAN. The treatment groups also showed higher fish yield performance and better hematological and serum biochemical parameters as compared to the control group, as plant-assisted bioremediation protects fish against ammonical stress. The study addresses the critical issue of ammonia management in aquaculture by developing an economically sound and sustainable bioremediation model based on the combined effect of biofilm and biofloc. The research enhances the understanding of ammonia’s impact on cultured species and offers a novel, cost-effective solution using lignocellulosic biomass.

There exists a need for simple, objective, noninvasive digital testing methods to ensure the quality of seafood products as they move from harvest sites to consumers. In this study, Paralichthys olivaceus sourced from a land-based aquaculture tank were harvested and bioelectrical impedance analysis (BIA) scores and organoleptic sensory data were recorded for each fish. The Certified Quality Reader 3.0 BIA device (“CQR®;” CQ Foods Inc.) used BIA data to generate a certified quality number (CQN) that was used to objectively quantify results. Organoleptic scores were obtained by Safe Quality Seafood Associates (SQSA) using standard methods. Mean CQN increased from day 1 to day 5 post-harvest and then decreased from day 5 to day 20 post-harvest. There was strong correlation between BIA data and organoleptic data, indicating the usefulness of BIA for objectively quantifying levels of degradation in this species of fish. Mean CQN and mean organoleptic scores were inversely related in post rigor mortis fish. Notably, BIA was able to differentiate objectively between fresh versus frozen fish samples. This study suggests that BIA can be used for rapid, noninvasive quality assurance of the degradation state of fish, though individual variability is high for measurements which may be controlled by the development of a standardized sample location.

The temperate genus Porphyra sensu lato has a long history of marine farming. Members of the genus are amongst the most common and economically valuable, commercially cultivated seaweeds on nets in the open sea. Species have a heteromorphic life cycle, alternating between a macroscopic blade and a microscopic, phase. The latter is an endolithic, shell-borne, filamentous thallus called the conchocelis which is cultivated separately within various bivalve shells in shallow ponds, on land. As a crop, its cultivation is accompanied by ever-increasing incidences of pests and diseases of both the blade and conchocelis phases. Serious damage is reported to be caused by the oomycete fungus Pythium (Py.) porphyrae and the chytrid Olpidiopsis spp., which have decreased the productivity of large-scale open sea farms especially in Korea and the northern coast of China. Interestingly, calcium propionate is effective combating oomycete infections. Early detection and development of resistant Porphyra strains, perhaps with some prophylactic, prebiotic treatments of low molecular weight oligoagars and selected probiotic, immune-stimulating bacteria might limit the damaging effects and economic consequences of this disease. In addition, cultivation nets are washed in acid to prevent carry over of disease-causing agents. As with any marine farming activity, epiphytes and grazers can also be issues faced by the farmers, but nothing as serious as the various rotting diseases. A summary of these studies is presented as a guide for rapid responses and applied management techniques for the amelioration of cultivation diseases, grazers, and harmful epiphytes affecting the two distinct phases of commercial Porphyra cultivation.

Nile tilapia stocking density effect is determined by growth performance, muscle protein composition, and production cost in the on-growing stage. Randomized Nile tilapia were stocked at three densities 59 (D59), 89 (D89), and 117 (D117) fish m⁻³ in four tanks per treatment. The experiment was performed in 12 indoor 40 m⁻³ rectangular tanks with brackish water (4 ppt salinity) and constant aeration for 69 days, analyzing final body weight (FBW), feed conversion ratio (FCR), final biomass (FB), food consumption (FC), average weight gain (AWG), biomass gain (BG), carcass yield (CY), fillet yield (FY), crude protein (CP), digestible protein (DP), true protein (TP), and unit production cost (UPC). Stocking density affected FBW, FCR, FB, FC, AWG, BG, CP, and DP (P < 0.05). FBW and AWG decreased significantly, and FCR, FB, FC, and BG increased significantly with increasing stocking density (P < 0.05); CP and DP ranged from 66.8 to 72.2% and 66.7 to 72.0% respectively, being higher in D59 and lower in D89. Stocking density had no effect on CY, FY, and TP of Nile tilapia (P > 0.05). Stocking density had a direct effect on UPC increasing with stocking density. Overall, high stocking density had a negative effect on growth performance, muscle protein composition, and production cost of Nile tilapia juveniles. These findings are important for vertically integrated tilapia farms due to high stocking densities resulting in a more expensive product with lower quality, which affects the tilapia production chain.

This study compared tubes and drums as containers for the grow-out culture of abalone Haliotis asinina using mixed seaweeds and formulated diet as feed. The recycled drums were newly tested containers for abalone culture as the cheaper and larger alternative. However, on the 10th month of culture, serpulids (Pomatoceros sp. and Spirorbis sp.) were observed on the abalone shells; hence, the 12-month culture was extended to 16 months to observe further the effects of these ectoparasites on the growth and survival of abalone. Throughout the culture period, abalone reared in tubes had significantly higher mean shell length and body weight than those reared in drums, measuring 45.42 ± 0.36 mm, 23.40 ± 0.99 g, and 41.45 ± 0.23 mm, 18.26 ± 0.40 g at harvest, respectively. Mean growth rates of those in tubes were significantly higher than those in drums before serpulid infestation but did not differ during months of infestation. Survival was consistently higher in tubes than drums, except during May–September 2023. At harvest, survival in tubes was 46.7 ± 11.0%, 37.8 ± 5.9% in drums. Daily water temperature ranged 28.00–32.33 °C, salinity 16.00–34.37 ppt. Monthly readings (ppm) of dissolved oxygen ranged 3.1–7.4, sulfide 0.00–0.73, phosphate 0.01–0.87, nitrate 0.00–0.99, nitrite 0.00–0.22, and total suspended solids 0.22–4.83. In April–October 2023, serpulids became prevalent (tubes = 31.5 ± 3.4%; drums = 38.3 ± 3.4%) when mean DO was significantly lower and sulfide higher than in June 2022-March 2023. These fluctuations in water parameters may have triggered the infestation, resulting in lower growth rates and abalone survival. But, despite these fluctuations and infestations, tubes remained a better culture container for the abalone.

Salinity could directly influence the survival and physiological conditions of fishes. Because of its importance, the salinity adaptation and osmoregulation mechanism have been extensively studied in the last decade. However, the adaptation to high-salinity environments has yet to be explored, particularly at the post-transcriptional level. In the present study, 18 RNA-seq datasets were utilized to investigate the alternative splicing (AS) events of functional genes in the gills of Mozambique tilapia (Oreochromis mossambicus) exposed to different salinity environments ranging from 0‰ (T0) to 110‰ (T110). A total of 1266 ~ 3194 differential alternative splicing (DAS) events were identified in 5 pairwise comparisons (T30 vs. T0, T50 vs. T0, T70 vs. T0, T90 vs. T0, and T110 vs. T0). It was derived from 971 to 2080 functional genes that were defined as DAS genes. Enrichment analysis indicated that these DAS genes in 5 comparison groups were commonly enriched in the spliceosome pathway. In detail, 31 spliceosome-associated genes were tightly related to spliceosome assembly, RNA binding, and RNA splicing. DAS events of these spliceosome-associated genes would alter the splicing decisions of downstream target genes. Differential expression analysis, together with protein interaction networks, was performed to determine their target genes. Functional categorization revealed that these target genes were mainly involved in energy metabolism in the mitochondrion, protein synthesis in the ribosome, and signal transduction in the cytoplasm, which may be responsible for the high-salinity adaptation in the gills of Mozambique tilapia. This study provides novel insights into the post-transcriptional regulation mechanisms underlying high-salinity adaptation in fishes.

Reference genes (RGs) are crucial for reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis as they allow accounting for uncontrolled environmental variations in gene expression results. Thus, prior reliability assessment of RGs is essential. In this study, candidate RGs were evaluated to investigate the gene expression responses of Piaractus mesopotamicus (pacu) reared in biofloc technology (BFT) and recirculating aquaculture systems (RAS). Samples from skeletal muscle (n = 9 BFT and 9 RAS) and kidney (n = 9 BFT and 9 RAS) were collected from juvenile pacu weighing 68 ± 4.43 g. The stability of three candidate RGs (GAPDH, ACTB, and 18S) was evaluated using GeNorm, BestKeeper, and NormFinder software. GAPDH was the least stable gene in pacu, due to high variability within and between BFT and RAS. In kidney tissue, ACTB was identified as the most stable gene by all three software. In skeletal muscle, NormFinder and BestKeeper classified 18S as the most stable gene, while GeNorm suggested a combination of 18S and ACTB. This is the first investigation on reference genes for qPCR in juvenile pacu tissues, and the findings will provide valuable support for gene expression studies in this species. Among the three candidate RGs tested in this study, ACTB and 18S genes are recommended for qPCR in kidney and muscle tissues of pacu, respectively, while GAPDH was deemed the least suitable. The observed differences in the expression of candidate genes among BFT and RAS and tissues emphasize the importance of appropriate RG selection prior to conducting RT-qPCR experiments.