Aquaculture Research最新文献

This study investigates the immunomodulatory effects of fish protein hydrolysates (FPHs) derived from Atlantic salmon (Salmo salar) by-products using the Dicentrarchus labrax brain (DLB-1) cell line. Utilizing aquaculture by-products for FPH production offers significant potential in aquaculture, providing both economic benefits and a reduction on environmental impact. FPHs contain bioactive peptides with several biological properties, including health-promoting, antioxidant, anti-inflammatory, and antimicrobial activities. This study focused on the immunological properties of three FPHs, namely SS1, SS4, and SS5, obtained from salmon skin by-products using enzymatic hydrolysis with trypsin, α chymotrypsin, and bromelain, respectively. Cytotoxicity assays showed that SS5 hydrolysate exhibited no toxic effects on DLB-1 cells, even at high concentrations (up to 80 µg/mL), unlike SS1 and SS4 that showed a 50% cytotoxic concentration (CC₅₀) of 7.0 and 11.8 µg/mL, respectively. Gene expression analysis revealed that SS1, SS4, and SS5 hydrolysates significantly upregulated the proinflammatory gene IL-1β (p  < 0.05), especially after LPS stimulation, indicating their potential to activate macrophages and modulate immune responses after bacterial infections. Interestingly, SS5 also significantly upregulated the anti-inflammatory gene IL-10 when treated with LPS (p  < 0.05), suggesting its ability to regulate inflammation and balance immune responses. These results highlight the role of hydrolysis conditions, such as enzyme selection and peptide molecular weight, in determining the bioactivity of FPH. Moreover, the study suggests that smaller peptides with mass >1.0 and <2.0 kDa, particularly those produced with the bromelain enzyme in SS5, exhibit enhanced anti-inflammatory properties. This research supports the use of FPH in promoting fish health by improving immune responses, and it contributes to sustainable aquaculture practices by transforming waste into valuable bioactive compounds, offering insights for future applications in functional feeds.

A 90-day nutritional trial was conducted to evaluate the effect of two dietary carbohydrate to lipid ratios and an attractant, star anise oil (Illicium verum), on marron (Cherax cainii Austin and Ryan, 2002) growth and organosomatic indices at 18 and 22°C under laboratory conditions. Three isonitrogenous diets were formulated, with two different carbohydrate to lipid (CHO:L) ratios, each with a crude protein level of 35%: D1 (CHO:L of 3.32), D2 (CHO:L of 3.22 + star anise oil), and D3 (CHO:L of 5.77 + star anise oil). Protein sources were also adjusted in D3 to allow for the higher carbohydrate content. Marron were held in cages to prevent cannibalism and to allow for individual feeding. The marron cultured at 22°C and fed D1 produced the highest specific growth rate (SGR), weight gain (WG), lowest molt intervals (MIns), and the lowest feed conversion ratios (FCRs). At 18°C, the highest molt frequency (MF) was in marron fed D1. The apparent feed consumption was highest at 22°C, and was unaffected by any diet. The total meat yield of marron was higher at 22°C when fed D3. The condition factor (CF) and organosomatic indices were unaffected by the diet, except the tail muscle moisture content (TM%) which was highest in marron fed D3 at 22°C. The supplementation of star anise oil did not increase the ingestion rate, and therefore, did not increase growth rates under laboratory conditions. Furthermore, a dietary carbohydrate to lipid ratio of 3.32 produced the highest growth rate of juvenile marron at 22°C, whereas there was no significant effect of diet on the growth rates at 18°C.

Probiotics are increasingly used in aquaculture to improve growth and water quality and boost disease resistance in farmed species. This study investigated the application of various concentrations of a commercial probiotic (mix of Bacillus subtilis and B. licheniformis) added to culture water to evaluate its effects on growth performance, water quality, and resistance to Vibrio parahaemolyticus infection. Over a 9-week trial, Pacific white shrimp (1.20 ± 0.01 g; stocked at 160 shrimp m⁻³) were reared in static biofloc culture systems consisting of 24 independent 156 L circular black polyethylene tanks. Shrimp were subjected to various probiotic concentrations weekly (×4, ×8, and ×16 of the recommended dose, which was one pellet per 200 g of feed) as three treatments. The control group (×0), without any probiotic addition, was used as the fourth treatment. Each treatment had six replicate tanks and shrimp were provided a commercial diet (Zeigler Shrimp Grower SI-35, CP 35%) four times per day via hand feeding. Following 9 weeks of culture, probiotic addition did not significantly impact growth or water quality (besides significant dissolved oxygen (DO) and temperature variations), but improved disease resistance. During the disease challenge, survival in all probiotic treatments (×4, ×8, and ×16) was significantly higher (regardless of dose) than that of the control group (x0; p < 0.05). These results suggest that the commercial probiotic may enhance shrimp resilience against Vibrio spp. infections. These findings suggest that although growth or water quality improvements were not confirmed in this trial, this probiotic appears to positively affect disease resistance in shrimp against V. parahaemolyticus infection in biofloc systems.

This study was conducted to investigate the effects of dietary cerium oxide nanoparticles (CeO₂-NPs), on growth performance, plasma biochemistry and histopathological changes of koi fish (Cyprinus carpio koi) exposed to florfenicol (FF) antibiotic in a 60-day experiment. The fish with an average weight of 2.38 ± 0.44 g were completely randomly distributed into six different groups with three replications. The experimental groups included: Basal diet without additives (control), basal diet + oral antibiotic, basal diet + antibiotic bath, basal diet supplemented with CeO₂-NPs, basal diet supplemnted with CeO₂-NPs + antibiotic bath, and basal diet supplemented with CeO₂-NPs + oral antibiotic. The experimental unit was a glass aquarium with a capacity of 110 L of water and 10 fish were stocked in it. At the end of the experimental period, growth performance of fish, blood plasma indices, and histopathology of liver, kidney, gill, and intestine were investigated. The results showed that the final body length of the fish in the basal diet + antibiotic bath group was significantly higher than the control group and the basal diet supplemented with CeO₂-NP + oral antibiotic group (p  < 0.05). Histological studies showed that the kidney, liver, and intestinal lesions of fish in different groups did not differ microscopically. In gill tissues, changes in secondary lamellae and their destruction occurred in different parts of the primary lamellae in different groups, but overall, no differences were observed among the different groups. The plasma aspartate transaminase (AST) and alanine transaminase (ALT) levels were significantly decreased in all groups compared to the control (p  < 0.05), except the basal diet supplemented with CeO₂-NPs + antibiotic bath group. The plasma blood urea nitrogen (BUN) level decreased significantly in the basal diet supplemented with CeO₂-NPs + antibiotic bath group compared to the control, while this value increased in the basal diet + oral antibiotic and the basal diet supplemented with CeO₂-NPs + oral antibiotic groups compared to the control (p  < 0.05). The results of this study revealed that adding CeO₂-NPs to the basal diet at level of 0.8 mg/kg decreased the alkaline phosphatase (ALP), AST, and ALP levels in plasma of koi fish compared to the control (p  < 0.05). The simultaneous administration of dietary CeO₂-NPs with the bath and oral FF antibiotic increased the AST and ALT levels and the BUN level in plasma, respectively (p  < 0.05).

In this study, the effects of dietary supplementation of Indian Sphagnum junghuhnianum peat moss pectin were evaluated in Catla catla fingerlings. A total of 375 fish (10.47 ± 0.2 g) were randomly divided (n = 25/tank) into basal diet (Sphagnum peat moss pectin [SPMP] at 0% control) (crude protein: 37%, crude fat: 8%) or four treatment diets, 2% (SPMP2), 4% (SPMP4), 8% (SPMP8), and 16% (SPMP16) for 60 days. The water temperature was 27.5 ± 0.6°C, and fish were fed with the experimental diets at 4% of their live body mass. The results of this research revealed that the SPMP8 diet substantially enhanced growth indices in catla fingerlings (p < 0.05). The highest and lowest whole-body lipid levels were in SPMP8 (5.03%) and control (4.06%), respectively. The gut amylase activity was significantly higher in the SPMP8 group, while lipase and protease remained unchanged. Additionally, fish given 8% and 16% SPMP had a significant decrease in the liver’s malondialdehyde concentration. Superoxide dismutase (SOD) activity was increased in SPMP-supplemented groups, with the highest value in group SPMP8 while catalase (CAT) activity was higher in SPMP4, SPMP8, and SPMP16 compared to the other groups. Supplementing the diet with 4%–16% SPMP increased the fish’s red blood cell count and hemoglobin level. An 8% SPMP diet increased white blood cell count, phagocytic activity, lysozyme, acid, and alkaline phosphatase (AKP) activities compared to the other groups. The cumulative mortality of fish after challenge with virulent Aeromonas hydrophila significantly decreased in SPMP8 and SPMP16 groups, compared to the other treatments. The results of this study indicated enhancements in immunological markers, specifically an increase in levels of AKP, SOD, and CAT. This research proposes that providing catla fingerlings with 8% SPMP effectively boosts their growth, immune response, and disease resistance.

Unproductive land affected by brackish water is a global challenge, particularly in aquaculture and agriculture; it has certain limitations that can hinder its use economically or ecologically, so it requires proper management to become more valuable and useful. This study evaluates the effectiveness of powdered and liquid organic fertilizers (LOFs) in a coculture system integrating rice and tiger shrimp cultivation on brackish water-affected land. The experiment was conducted on 12 pond plots, each measuring 560 cm², with four treatments: (a) LOF; (b) powdered organic fertilizer (POF); (c) a combination of liquid and POFs (LPOFs); and (d) no fertilizer (NF). Observed parameters included rice plant growth, tiger shrimp growth and survival rates, and water quality, measured every 14 days. The findings revealed that the highest growth and survival rates of tiger shrimp (8.48 g/individual and 76%, respectively) were achieved with LPOF treatment. In comparison, the lowest growth and survival rates (4.84 g/individual and 37%) occurred without fertilizer. Tiger shrimp weight increased significantly over 70 days, from an initial average of 0.2–8.48 g/individual (LPOF) and 6.58 g/individual (NF); likewise, the rice plant grows well during 105 days of maintenance. Organic fertilizer applications proved beneficial for rice and shrimp, enhancing plankton growth and serving as a natural feed source for shrimp. This reciprocal relationship demonstrates the potential of organic fertilizers to boost productivity and sustainability in rice-shrimp coculture systems. This research offers valuable insights and practical strategies to overcome the challenges faced by tiger shrimp farmers in brackish water aquaculture.

Microalgae are highly nutritious and fast-growing organisms that are utilized in aquaculture as premix for feed formulation and as live feed for the larvae culture industry. The aim of the research was to reduce live feed production costs for aquaculture through the utilization of cow dung as a biological waste. This research reports on the growth, pigments, and nutritional contents of two marine microalgal species (Chlorella sp., and Gonyostomum sp.). Each of the microalgae was cultured in four treatments: C (control, conway medium), T1 (50% conway, 50% cow dung), T2 (25% conway, 75% cow dung), and T3 (100% cow dung). The outcomes exhibited that the C treatment of Chlorella sp. and T1 treatment of Gonyostomum sp. had the highest growth in terms of cell density. Moreover, both species had significantly higher (p  < 0.05) protein percentage in C which were 42.7% ± 4.03%, and 42.9% ± 1.96%, respectively, and greater total lipid and carbohydrate contents in either T1 or T2 treatment. Gonyostomum sp. exhibited the highest carotenoid content (2.48 ± 0.09 µg/mL) in C, while Chlorella sp. had significant amount of total phycobiliprotein contents in all treatments compared to Gonyostomum sp. Although polyunsaturated fatty acid (PUFA) contents were higher in conway medium, both of the microalgae in T1 and T2 treatments had high saturated fatty acids (SAFA) and monounsaturated fatty acid (MUFA) contents. Furthermore, both species had notable concentrations of nonessential amino acids in comparison to essential amino acids. The cost estimation confirmed C had the highest preparation cost compared to other treatments.

Inland aquaculture using underground brackish water is a promising method to alleviate pressure on freshwater resources. Nile tilapia stains utilized for commercial production can also tolerate low-salinity brackish water. Therefore, the goal of this study was to compare the reproductive performance of females and males of five genetically different Nile tilapia strains under brackish water cultivation. The GIFT, Big Nin, Mag Nin, Thai red, and Taiwanese red strains, with initial mean weights of 165.5 ± 18.3, 157.8 ± 26.1, 157.1 ± 27.6, 163.3 ± 26.3, and 175.9 ± 27.3 g (±standard deviation), respectively, were used. The fish were individually tagged and each strain was maintained in 8 m² rectangular concert tanks for 120 days (two fish/m²). The fish were fed at 1.5% of their body weight twice a day with a commercial diet (42% crude protein) at 29.0 ± 0.5°C. The highest female body weight was obtained in the red color strains (Thai and Taiwanese strains) compared to Big Nin strain (p < 0.05) and it was not significantly different in other black tilapia strains. The results of the reproductive indices including spawning frequency and cycles, fertilization and hatching rates, and hepatosomatic index indicated no significant differences among the strains (p > 0.05). However, Mag Nin strain exhibited higher working and relative fecundity values than GIFT strain. A longer reproduction cycle was recorded in GIFT strain than Taiwanese red strain (p < 0.05). In terms of egg quality, no significant differences were obtained among the tilapia strains. A higher sperm motility was recorded in GIFT strain than Mag Nin strain, while other groups showed no significant differences. Overall, GIFT strain demonstrated superior values of sperm motility and reproduction cycles, while Mg Nin strain showed high working and relative fecundity values. The results of the reproductive performance of each genetically improved Nile tilapia strain will be discussed by fish farmers upon their specific environmental conditions and production goals.

Gracilaria verrucosa and Ulva lactuca were cocultured with Crassostrea belcheri for 120 days in captivity while controls were the independent culture of these three species. The study assessed the water quality parameters, growth performance, proximate and biochemical composition of the organisms undergoing the different treatments. Moreover, they were compared with outdoor farmed seaweeds and oysters to assess their nutritional quality. Significant variations were seen in the growth rates of the two seaweeds, U. lactuca exhibiting the highest live weight gain (LWG) and specific growth rate (SGR) in coculture settings. The percentage of surviving oysters varied from 60% to 80% across experiments, with the fastest growth rates observed when cocultured with U. lactuca. The seaweeds’ moisture, ash, protein, carbohydrate, and fiber contents varied significantly, with U. lactuca (indoor) having the highest protein and carbohydrate content (p < 0.05) compared to U. lactuca (outdoor) and G. verrucosa (indoor and outdoor), and also recording the maximum total chlorophyl, carotenoids, and fucoxanthin. Significant variations were found in the fatty acid content of seaweed and oyster samples. Outdoor oyster samples had more omega-3 fatty acids (p < 0.05) than indoor while the indoor seaweed samples had lower saturated fatty acids (SAFA), and higher polyunsaturated fatty acids (PUFA) than outdoor. U. lactuca grown indoors exhibited the highest levels of both essential amino acids (EAAs) and non-essential amino acids (NEAAs). The study emphasizes how culture conditions affect the nutritional and biochemical profiles of seaweeds and oysters, and it offers indoor coculture as a potential substitute for inclement environmental conditions and as a backup strategy to enhance sustainable seaweed mariculture that allow for optimal growth and nutritional quality ensuring the maximum space utilization.

Canadian salmonid aquaculture provides a sustainable protein source; however, there are concerns that Atlantic salmon (Salmo salar L.) mariculture reduces wild Pacific salmon survival through interspecific disease transfer. Tenacibaculosis, caused by species of Gram-negative bacteria in the genus Tenacibaculum, has the potential to be transmitted interchangeably between farmed Atlantic salmon and wild Pacific salmon, though there is a lack of corroboration establishing transmission. To provide evidence for interspecific horizontal transmission of tenacibaculosis from Atlantic salmon to Pacific salmon, Atlantic salmon were bath-exposed to an isolate of Tenacibaculum maritimum and cohabitated with naïve Atlantic or Chinook salmon (Oncorhynchus tshawytscha W.) for 25 days. Exposed and naïve cohabitant Atlantic salmon exhibited morbidity with multifocal superficial and ulcerative epidermal lesions with intralesional T. maritimum (culture, histology, and qPCR). At 10⁸ CFU mL⁻¹, exposed and naïve cohabitant Atlantic salmon had 43% and 60% mortality, respectively. Contrastingly, cohabitant Chinook salmon experienced no morbidity or mortality, despite successful culture of T. maritimum (10⁸ CFU mL⁻¹n = 5/6 fish; 10⁶ CFU mL⁻¹n = 0/6 fish) from skin swabs. These findings suggest that BC Chinook salmon do not develop clinical tenacibaculosis through interspecific horizontal transmission from farmed Atlantic salmon with mouthrot under the tested conditions and that the presence of T. maritimum alone is insufficient for disease. Further research needs to clarify the genetic differences between hosts and pathogens in different geographical locations, and investigate additional T. maritimum isolates, alternative Tenacibaculum species, environmental variables, and temporal scales that could lead to clinical tenacibaculosis in Chinook salmon.