Aquaculture International最新文献

Whereas most analyses of prices for seafood have focused on point-valued prices, typically means over a period, in this paper we analyze time series of the intervals created by the maximum (i.e., high) and the minimum (i.e., low) prices constructed at monthly frequency. This is important as seafood prices in general are characterized by high volatility. Our econometric analysis is based on the notion that the highs and the lows of prices of a fish product could be cointegrated. That is, there is a stable, long-term relationship between highs and lows of prices of a given fish product so that they do not drift apart forever even though they might move up and down on their own in the short term. Our results indicate that the aquaculture product prices tend to adjust faster towards their long-term equilibrium relationship after a market shock, compared to prices of capture fisheries products.

The combined toxic effects of nanoplastics (NPs) and heavy metals on aquatic organisms have attracted widespread attention. The mechanism of the effects of combined exposure to NPs and Cu²⁺ on crustaceans remains unclear. This study aimed to evaluate the effects of NPs and Cu²⁺ on the antioxidant capacity, immune response, and gut microbiota of Eriocheir sinensis. Both NPs and Cu²⁺ exposures disrupted the morphological integrity of the gut tissues of E. sinensis. Both combined exposures increased the levels of intestinal antioxidant indices (SOD, CAT, GSH, and MDA) and hemolymphatic enzyme activity indices (TP, ALP, ALT, AST, CK, and LDH) compared to NPs and Cu²⁺ single exposure. The results of intestinal flora showed that NPs and Cu²⁺ exposure increased harmful bacteria. Combined exposure reduced the abundance of Proteobacteria and Vibrio compared to NPs and Cu²⁺ single exposure. This study indicates that E. sinensis may regulate the combined toxicity of NPs and Cu²⁺ through alterations in the intestinal microbiota, providing a potential reference for elucidating the mechanisms of joint toxicity of NPs and Cu²⁺ in aquatic species.

Current debate on the sustainability of using cleaner fish to control parasitic lice in salmon farming suffers from extremely variable scientific evidence on the efficacy of this practice. This paper presents novel experimental results on evacuation rates of salmon lice through the digestive tract of ballan wrasse. These results are combined with quantitative field data on contents of salmon lice in ballan wrasse, to derive a method to study the efficacy of ballan wrasse in cleaning salmon of salmon lice. From a fitted binomial regression model on the probability of finding lice in the digestive tract after ingestion, we found a median evacuation time of 11.0 h. The mean evacuation time was 12.2 h. Furthermore, by integration, we found that if a wrasse on average consumes one louse per day, then the expected number of observable lice in the digestive tract is 0.472. This gave an estimated daily consumption of salmon lice per wrasse expressed as the number of salmon lice in the digestive tract divided by 0.472. As an example, analyses of lice contents in the digestive tract of 6406 ballan wrasse used as cleaner fish in salmon farming revealed that salmon lice were found in 2.9% of the wrasses, with a mean number of 0.15 lice per fish. This translates to an estimate of 0.32 lice consumed per day per ballan wrasse. The present way of estimating the efficacy of wrasse as cleaner fish may contribute to a more robust evaluation of louse control effects of ballan wrasse.

The transport of fish is a critical stage in aquaculture, as it may cause stress and compromise animal health. The use of phytotherapeutics, such as essential oils, has been investigated as an alternative to mitigate the negative impacts of this management practice. This study evaluated the effect of essential oil Lippia origanoides (EOLO) in the transport water of Nile tilapia (Oreochromis niloticus) juveniles. Four EOLO concentrations (5, 10, 15, and 20 mg L⁻¹) and a control were tested in a completely randomized design with four replicates during a 5-h transport period. Water quality parameters, survival, hematological and biochemical indices, and gill histopathological changes were analyzed. Transport increased dissolved oxygen, electrical conductivity, and total ammonia levels, but values remained within non-toxic limits for the species. Survival was 100% at the end of transport, with no significant differences during recovery. No relevant changes were observed in hematological or biochemical parameters, except for an isolated increase in AST in the 10 mg L⁻¹ group. Gill histological changes were classified as mild and attributed to transport itself, only the concentration of 20 mg L⁻¹ of EOLO differed from the control group. It can be concluded that EOLO, at concentrations up to 20 mg L⁻¹, can be safely used in the transport water of Nile tilapia juveniles, representing a natural and potentially sustainable approach to decreasing reliance on synthetic anesthetics in aquaculture.

In order to boost productivity based on mutual gain for the co-cultured species and enhanced ecosystem health, integrated multi-trophic aquaculture (IMTA) combines species from various trophic or nutritional levels in a single system. In Bangladesh’s coastal regions, edible oysters, Crassostrea belcheri, are widely available. Because it is a filter-feeder, it can be employed as an extractive species in IMTA to remove organic materials. An experimental trial was carried out to gauge the impact of varying C. belcheri stocking densities on the performance, i.e., growth, feed utilization, and economic returns of seabass (Lates calcarifer) and sea lettuce (Ulva lactuca) and environmental remediation in an IMTA system. Seabass (200.51 ± 0.05 g) were placed in 750-L fiber-reinforced plastic (FRP) circular fish tanks (FT) with 1.5 (T₁) and 2 (T₂) kg/m³ of oyster and seaweed (500.36 ± 0.02 g) in hydroponic tanks (HT), respectively. The same quantity of seabass and seaweed without oysters was stocked in the control tanks. There were three duplicate tanks for each of the two treatments and the control. The results showed that treatment T₂ yielded the highest final weights for both seaweed (4245.12 ± 9.24 g) and seabass (527.19 ± 2.31 g), which were significantly greater (p < 0.05) than those recorded in the control group (2452.12 ± 7.12 g for seaweed and 442.33 ± 1.89 g for seabass). Seabass and oyster survival did not differ; however, T₂ had the highest rates of both. According to this experiment, when stocked at a density of 2 kg m⁻³, the oyster C. belcheri can function as an efficient extractive species in the IMTA system. As a result, treatment T₂ IMTA was more effective and had a positive environmental bioremediation impact.

Magnesium (Mg) in feed or water is critically important for the growth and molting of crustaceans. The aim of this study was to determine the optimal water Mg concentration for the aquaculture of Chinese mitten crabs (Eriocheir sinensis) (initial body weight: 30.11 ± 0.93 g). Six experimental groups (M0, M15, M30, M45, M60, and M75) were established with varying Mg levels for eight weeks to evaluate growth, Mg deposition, antioxidant capacity, immunity and molting performance. A total of 240 male crabs with intact appendages were randomly allocated to 6 treatment groups (4 replicates per group, 10 crabs per replicate). Results showed that the M30 group exhibited superior growth, molting and immune responses (P < 0.05). Meanwhile, a significant upregulation was observed in genes related to the antioxidant and non-specific immune defense systems and the molting signaling pathway (P < 0.05). While Mg deposition in gill and hepatopancreas tissues significantly increased in the M60 and M75 groups (P < 0.05), excessive Mg²⁺ concentrations (M60 and M75) inhibited growth, molting and immune function and caused tissue damage. Additionally, Mg affected ecdysteroid and molt-inhibiting hormone levels in hemolymph (P < 0.05). The ‌broken-line model‌ and quadratic regression model analysis identified ‌33.84–37.37 mg/L Mg²⁺‌ as the optimal concentration for culturing E. sinensis. This research identifies the optimal Mg²⁺ concentration for E. sinensis aquaculture industry, establishing a scientific foundation for future mineral nutrition studies.

Ectoparasitic infestations present a significant challenge to aquaculture health management by disrupting the oxidative stress balance, immune defense mechanisms, and energy metabolism of European seabass (Dicentrarchus labrax). These effects are further influenced by seasonal environmental changes that impact both host physiology and parasite prevalence. This study assessed seasonal changes in oxidative stress, immune response, energy metabolism, growth, and tissue damage in a total of 200 European seabass collected seasonally from a marine fish farm in Damietta, Egypt. Fish showed increased oxidative stress and immune activity in the autumn, the winter, and the spring, with glutathione (GSH) peaking in the spring, while malondialdehyde (MDA) and nitric oxide (NO) levels increased in autumn and winter. Immune markers like immunoglobulin M (IgM) and lysozyme were significantly elevated in winter and spring, while interleukin-1β (il-1β) increased during autumn and winter. Liver energy biomarkers increased during autumn and spring compared to summer and winter. Histopathological lesions, including necrosis, hemorrhage, and inflammation, were found especially during temperature extremes. Principal component analysis (PCoA) revealed biomarker clusters linked to parasite loads and environmental stress. Seasonal infestations induce oxidative damage, immunological problems, and metabolic changes that compromise fish health. These findings highlight the significance of employing oxidative, immunological, and metabolic biomarkers as indicators of ectoparasitic stress, enabling seasonal health management measures to improve fish welfare and mitigate production losses in aquaculture.

Three Trials were performed to understand better how soy processed in different ways impacts the growth, feed conversion ratio, and health of the Florida pompano (Trachinotus carolinus). The first two growth Trials were performed to evaluate the efficacy of an open soy-based diet compared to a commercially produced, fish meal (FM)–based diet. Trial 1 compared a soy-based diet to a commercial FM-based diet using juvenile fish (23.2 ± 1.87 g) across six replicates over 42 days. The FM-based diet significantly outperformed the soy diet in final biomass (p = 0.026), weight gain (p = 0.006), and feed conversion ratio (FCR) (p = 0.015). Trial 2 used larger fish (38.1 ± 0.86 g) with three replicates over 56 days and found no significant differences between diets. Histological samples of the distal intestine showed no statistical differences in symptoms conducive to soy-induced enteritis between the practical soy diet and the commercial FM diet. Trial 3 evaluated nine experimental soy-based diets in juvenile pompano (4.82 ± 0.09 g) across quadruplicate tanks for 76 days. The basal diet containing 49.97% solvent-extracted soybean meal (SBM) was compared with diets where SBM was replaced at 50% or 100% with low oligosaccharide SBM, soy protein concentrate, or enzyme-treated SBM, or at 25% or 50% with expeller-extruded SBM. No significant differences were found in weight (p = 0.493), survival (p = 0.925), or FCR (p = 0.874). Histological analysis showed no adverse intestinal effects in lamina propria thickness, lamina propria cellularity, connective tissue thickening, or abundance of goblet cells.

The adoption of high-fat diets (HFD) in aquaculture, while economically beneficial, often induces hepatic injury, posing a major challenge to farmed fish like Monopterus albus. This study aimed to investigate the potential of dietary soy isoflavones (SIF) to alleviate HFD-induced liver damage by concurrently modulating lipid metabolism, oxidative stress, endoplasmic reticulum stress (ERS), and inflammation. Four isonitrogenous diets were formulated: a control diet (CON, 5.96% lipid), a high-fat diet (HFD, 11.96% lipid), and the HFD supplemented with 50 or 100 mg/kg SIF (HSIF50 and HSIF100 groups, respectively). Following an 8-week feeding trial, the HFD group exhibited significantly impaired growth performance and intestinal digestive enzyme activity, alongside severe hepatic steatosis. This was driven by a marked dysregulation of hepatic lipid metabolism, evidenced by upregulated lipogenic genes (srebp1, fas) and downregulated β-oxidation genes (aco, cpt1). Furthermore, HFD feeding triggered substantial hepatic injury, characterized by exacerbated vacuolization, diminished antioxidant capacity (reduced SOD and CAT activities), induced ERS (elevated grp78 and atf6), and activation of pro-inflammatory cytokines (upregulated il1β and tnfα). Dietary SIF supplementation, particularly at 50 mg/kg, effectively mitigated these adverse effects by restoring lipid metabolic balance, enhancing antioxidant defenses, alleviating ERS, and suppressing inflammatory responses. These results demonstrate that SIF confers hepatoprotection in M. albus by targeting the integrated pathway of metabolic and cellular stress, with an optimal dose of 50 mg/kg. Further studies should explore the long-term effects and molecular mechanisms underlying SIF-mediated protection in aquatic species.