Aquaculture International最新文献

Vibrio parahaemolyticus is associated with severe food-borne illness in humans as well as substantial financial setbacks in the fishing sector. To investigate the prevalence, pathogenicity, virulence, as well as the resistance patterns of V. parahaemolyticus retrieved from Oreochromis niloticus, 180 O. niloticus (moribund fish; n = 120 and apparently healthy; n = 60) were indiscriminately collected from Lake Manzala, Egypt. Consequently, the clinical inspection, necropsy finding, and bacteriological analysis were performed. All the retrieved isolates tested positive for the groEL species-specific gene. Herein, the prevalence of V. parahaemolyticus in the collected fish was 8.9% (16/180), whereas the liver was the organ most prominently affected. PCR revealed that the most prevalent virulence-determinant genes associated with V. parahaemolyticus were the toxR and tlh genes (100% for each), then tdh (73.3%) and trh (26.7%) genes. Furthermore, 40% (18/45) of isolated V. parahaemolyticus were extensively drug-resistant (XDR) to seven antimicrobial classes and have bla_TEM, bla_OXA, sul1, aadA, ermB, and tetA genes. Additionally, 17.8% (8/45) of the obtained V. parahaemolyticus were multidrug-resistant (MDR) to three antimicrobial classes and owned bla_TEM, ermB, and aadA genes. The pathogenicity assay accentuated the correlation between cumulative mortality and the virulent characteristics exhibited by the inoculated strain. Definitely, 77% mortality was recorded within eight days in fish injected with a virulent V. parahaemolyticus strain. Briefly, this research accentuated the occurrence of XDR V. parahaemolyticus in fish specifying a public health concern. The emerging MDR and XDR V. parahaemolyticus frequently harbored toxR, tlh, and tdh virulence genes, and bla_TEM, bla_OXA, sul1, aadA, ermB, and tetA or tetB antimicrobial resistance genes.

The aim of this study was to evaluate the impacts of dietary Gracilaria spp. and Sargassum spp. on growth, immunity, antioxidant status, and fatty acid composition of Sobaity seabream (Sparidentex hasta). A total of 540 Sobaity seabream juveniles (19.6 ± 0.5 g) were stocked into 18 tanks (300 L) and divided into six groups (three replicates per group). Fish were fed diets containing 0 (control), 3% (GS3), 6% (GS6), 9% (GS9), 12% (GS12), and 15% (GS15) Gracilaria and Sargassum mixtures in equal amounts for 8 weeks. The results showed that final weight, weight gain rate, and specific growth rate were significantly higher in fish fed GS6, GS9, and GS12 groups. Serum lysozyme, ACH50 activities, complement 4 (C4), and total Ig values were significantly increased in fish fed the 6% and 12% macroalgae mixture. The lowest liver catalase activity was found in the control, while liver superoxide dismutase (SOD) activity in the GS9 and GS12 groups was significantly higher than in the GS3 group. The highest and the lowest values of liver glutathione were observed in the GS12 and GS15 groups, respectively. Liver total antioxidant capacity content was also the highest in the GS12 group. Insulin-like growth factor-1 (IGF-1) relative expression level, in the liver of fish, was increased in the GS6-GS12 groups. Lysozyme relative expression level was significantly higher in the liver of fish fed macroalgae. Arachidonic acid (ARA) and eicosapentaenoic acid (EPA) were significantly higher in the GS9, GS12, and GS15 groups than in the control. Moreover, there were no significant differences in the amounts of docosahexaenoic acid (DHA), n-3 and n-6 polyunsaturated fatty acids (PUFA), long-chain PUFA, and n-3/n-6 PUFA among the experimental groups. Therefore, adding 9–12% Gracilaria and Sargassum macroalgae mixture in equal amounts to fish diets can be recommended to improve growth performance, innate immunity, liver antioxidant status, and muscle fatty acid composition in Sobaity seabream.

The study investigated the effect of replacing fishmeal by varying levels of hydrolyzed feather meal (HFM) as well as dietary probiotic supplementation on growth performance, digestibility, histology, and gene expression of juvenile rainbow trout (Oncorhynchus mykiss). Five iso-nitrogenous (average of 50.60% crude protein), iso-energetic (average of 21.79 kJ/g), and iso-lipidic (average of 21.86% crude lipid) diets were formulated and fed to triplicate groups of juvenile rainbow trout weighing 29.65 ± 0.39 g (mean ± SD) for 75 days. Dietary treatments included one control (50% fishmeal) and four experimental diets, each containing 2 g/kg probiotics (Lactobacillus plantarum and Bacillus subtilis). The experimental diets included HFM30 (150 g/kg HFM, 9 g/kg lysine, and 4 g/kg methionine), HFM35 (175 g/kg HFM, 11 g/kg lysine, and 5 g/kg methionine), HFM40 (200 g/kg HFM, 13 g/kg lysine, and 6 g/kg methionine), and HFM45 (225 g/kg HFM, 15 g/kg lysine, and 7 g/kg methionine). Up to 40% replacement of fishmeal with HFM showed no significant difference compared to control group in growth performance (P > 0.05). Feed utilization of HFM45 was slightly lower than control and all the other experimental groups. There was no statistically significant difference in FCR value between HFM40 and control groups (P > 0.05). The apparent digestibility coefficients (ADCs) for protein and amino acids were very high in all groups (P < 0.05). Intestinal mucosa and sub‐mucosa layers of experimental fish showed general tissue integrity with no signs of tissue necrosis. For intestinal morphology, where 45% HFM replacement was applied, villus length to crypt depth (VL to CD) and villus surface area (SA) decreased by 46.01% and 44.44%, respectively, compared to the control group (P < 0.05). This situation shows that intestinal morphology can be damaged when the highest level (HFM45) of feather meal is used. Dietary HFM upregulated growth-related genes such as IGF-II, IGFBP-1b, IGFr1a, GDF9, and FGF2 and downregulated GHR-I and IGF-I. Overall, inclusion of HFM at 40% showed similar results to control group in juvenile rainbow trout feeding.

Algal oligosaccharides (AOS) have been shown to effectively promote plant growth. While there have been many studies on the use of AOS in promoting crop growth, few have investigated their potential in improving ecological floating bed wastewater treatment. Therefore, this paper aims to explore the effects and mechanisms of AOS in enhancing ecological floating bed wastewater treatment. Water spinach was cultivated in aquaculture wastewater treated with varying concentrations of AOS (0.025, 0.05, 0.1, and 0.2 mg/L), with an ecological floating bed without AOS serving as the control group. Results shows the addition of AOS can significantly enhancing ecological floating bed plant and microbial accumulation, resulting in profound improvement in ecological floating bed wastewater treatment efficiency. This is evident in the increased plant height, stem diameter, main root length, number of roots, leaf area, above water-surface fresh weight, below water-surface fresh weight, above water-surface dry weight, below water-surface dry weight, chlorophyll a, chlorophyll b, and chlorophyll content. The combination of 0.05 mg/L AOS with the ecological floating bed exhibits the most favorable results, with percentage increases in various indicators were 44.0%, 52.9%, 29.9%, 62.0%, 28.0%, 141.6%, 84.0%, 97.7%, 220.0%, 24.6%, 34.2%, 26.9% compared to the control group. The addition of AOS to the water spinach ecological floating bed system significantly enhances the removal efficiency of water turbidity, chemical oxygen demand (COD), ammonia nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃⁻-N), total nitrogen (TN), and total phosphorus (TP) water quality indicators. This experiment also investigated the differences in microbial community structure between the control group and the group with the optimal concentration of AOS to study the mechanism of action of AOS. The combination of 0.05 mg/L AOS with the ecological floating bed demonstrates the optimal removal efficiency. This study offers crucial technical insights for further optimizing ecological floating bed technology and improving water purification efficiency.

Aeromonas hydrophila is an important etiologic agent, triggering an increased trend of disease outbreak in fish farming. In this investigation, we evaluated pathological response in the midgut and liver of three types of grass carps after gut infection. Severe pathological levels of tissue necrosis were observed in common grass carp (GC) and gynogenetic grass carp (GGC), but mild pathological symptom was detected in hybrid grass carp (DRGC), along with the dramatically increased number of goblet cells. Moreover, three types of grass carps showed upregulated levels of immune gene patterns and antioxidant abilities, whereas inflammatory cytokine expression levels in hybrid grass carp (DRGC) were lower than that of gynogenetic grass carp (GGC) and common grass carp (GC). These results suggested that DRGC may exhibit a disease tolerance against A. hydrophila-induced tissue inflammation.

Aquaculture is an important economic and food source in many countries. Due to environmental restrictions and the effects of aquatic diseases, aquaculture requires a lot of labor and expensive materials, and it relies on the expertise of aquaculture experts. The quality of water is essential for aquaculture development. Therefore, in this paper, a novel aquaculture water quality monitoring using autonomous sensors (AquaSense) has been proposed which uses autonomous sensors for efficient monitoring of water in the aquaculture environment. In the AquaSense framework, temperature, pH, dissolved oxygen, and salinity measurements are recorded and collected using a variety of autonomous sensors. Based on the information gathered, users can assess the condition of their farm through the Internet. The MATLAB R2012b platform is employed to verify the effectiveness of the suggested water quality (WQ) monitoring technique and analyze the data. Several criteria including accuracy, precision, recall, specificity, and f1-score have been used to assess the effectiveness of the suggested strategy. AquaSense achieves the high accuracy ranges of 96.98%, and existing techniques ISAS, AquaStat, and IoT-WQI FIS achieve 91.24%, 93.39%, and 88.92%, respectively.

This study aimed to investigate the impact of partially substituting fish meal (FM) and soybean meal (SBM) in the diet with fermented soybean meal (FSBM) on growth, feeding preference, protease activity, and their correlation with gastric evacuation in giant freshwater prawn, Macrobrachium rosenbergii. A 55-day feeding trial was conducted with eight isonitrogenous and isoenergetic diets, followed by a gastric emptying experiment. The results showed that the control group (containing 30% FM and 18% SBM) exhibited the highest feeding preference index, and the SBM-free group (almost devoid of soybean antigen proteins) showed the lowest preference index. Moreover, all diets displayed an initial decrease in preference index followed by an increase and subsequent decline with increasing levels of supplemental fermented soybean meal. This pattern was also observed in terms of digestive enzymes and stomach emptying rates. Notably, there was the same tendency in feeding preference before and after short-term domestication (55 days), and it was consistent with the trend of feeding rate. All the presented findings indicated that the inclusion of fish meal is a crucial factor influencing the feeding preference of M. rosenbergii. The substitution of fish meal and soybean meal in feed with fermented soybean meal would induce feed aversion in M. rosenbergii, which significantly contributes to the decline in growth rate. However, when fermented soybean meal replaced fish meal and soybean meal, the individual action or interaction between antigenic proteins and other anti-nutritional factors resulted in varying changes in digestive enzyme activity and gastric evacuation dynamics.

The intensification of aquaculture industries around the globe has led to increased susceptibility and exposure to diseases. To ensure the well-being of animals and the profitability of the industry, many aquaculture farms resort to antibiotic treatments. However, with the increasing presence of antimicrobial resistance (AMR), it has become important to regulate and limit the use of antibiotics, especially in animal production and regarding the antibiotics that are deemed as critically important for human health by the World Health Organization (WHO). This review describes how AMR mitigation strategies have developed over time in international settings and how they relate to aquaculture. Furthermore, we analyzed how different countries and regions abide by these statutes, as well as the antibiotic standards from a selection of certification schemes. Our results show that the role of aquaculture has been inexplicitly addressed in international guidance documents and that there is a need to further increase the activities of aquaculture operations in combating AMR, with an emphasis on alternatives to antibiotic use. We also found that most countries and regions allow the highest priority-, or critically important antibiotics in aquaculture, which could have detrimental effects on animal, environmental, and public health. As a result, most countries fail to comply with the recommendations and standards set by international organizations and certification schemes.

The thymol chemotype of the essential oil of Thymus vulgaris (EOTV-T) and its nanoemulsion (NEOTV-T) were investigated as anesthetics in the management of Colossoma macropomum. The stability of nanoemulsions was analyzed by zeta potential and dynamic light scattering for an interval of 37 days prior to carrying out two anesthesia experiments. The first experiment determined anesthesia induction and recovery intervals for juveniles anesthetized with different concentrations of EOTV-T and NEOTV-T. Based on the obtained induction and recovery curve, the second experiment adopted concentrations of 75 mg/L of EOTV-T and 50 mg/L of NEOTV-T for use during biometric management every 10 days for 60 days of cultivation of juvenile C. macropomum. The results showed that NEOTV-T had an average diameter of less than 100 nm for up to 22 days and was more effective at inducing anesthesia than EOTV-T. The continuous use of anesthetics during biometrics did not affect juvenile performance in terms of growth, feed consumption, and survival. Furthermore, no significant differences were observed in hematological and biochemical parameters between juveniles of the control treatment and those subjected to biometric management using 75 mg/L of EOTV-T and 50 mg/L of NEOTV-T. It can be concluded that the essential oil of T. vulgaris and its nanoemulsion can be used to facilitate the management of juvenile C. macropomum without compromising their performance or well-being.

A 75-day rearing trial was completed to investigate the effectiveness of different biofloc systems (BFT) on the water quality, growth performance and health status of Florida red tilapia (FRT) grown in brackish groundwater (BGW). The trial consisted of the control and three types of BFT using different carbon sources (CS), starch (ST), rice bran (RB), and wheat bran (WB) in triplicate, expressed as BF-0, BF-ST, BF-RB, and BF-WB, respectively. Fish weighing 4.98 ± 0.01 g/fish were stocked in 250-L tanks at an initial stocking density of 25 fish. The findings demonstrated significant reductions in inorganic nitrogen by-product (NH₃ and NO₂) levels in all BFT groups compared to the control, with an increase in floc volume and floc nutritional value, in the BF-ST and BF-RB groups. Furthermore, fish in the BF-ST and BF-RB groups showed significant improvements in fish growth indices (final weight, weight gain, and FCR). Fish in the BFT groups showed significant improvement in kidney function indices and plasma lipids with no significant changes in liver enzyme activity compared to the control. Lower stress markers (glucose and cortisol) and higher digestive enzyme activity (lipase and protease), innate immune parameters and antioxidants were reported in fish of the BF-ST and BF-RB groups compared to the control fish. Histopathological inspection revealed that the BF-ST fish exhibited healthier livers and shared healthier intestines with BF-RB fish compared to the control group. In conclusion, RB is an appropriate CS with BGW for desert aquaculture due to its availability, inexpensiveness, and comparable outcomes with ST.