Aquaculture International最新文献

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.

Pugheadedness and shortened lower jaw are frequent abnormalities in reared fish, developing during the early life period up to metamorphosis. In this study, we examined whether these abnormalities in gilthead seabream (Sparus aurata Linnaeus, 1758) could recover during the on-growing period. Furthermore, we examined whether jaw abnormalities affect fish survival and growth rates. At 123 days post-hatching (dph, ca 5.0–7.5 cm standard length, SL), 197–204 seabream juveniles with normal (Nor), pugheaded (UpJ), and shortened lower jaw (LoJ) phenotype were introduced in a common rearing tank. At 162 dph (8.0 ± 0.7 cm SL), fish were pit-tagged and transferred to a sea cage for on-growing up to 514 dph (23.8 ± 1.4 cm SL). Following the morphological examination of fish at 162 and 514 dph, pugheaded individuals were classified into two morphotypes, with (UpJ-Kub) or without (UpJ-Par) gross defects on the maxillary and premaxillary bones. During the on-growing period, 30.4% of the UpJ-Par fish turned into a normal phenotype. No recovery was observed in LoJ and UpJ-Kub juveniles. Geometric morphometric analysis revealed no significant differences in the head shape between the UpJ-Par fish with a recovered phenotype (Rec) and the normal group (p > 0.05, Procrustes distance). A three-landmark-based angle on the snout area was effective in discriminating the normal juveniles (An_sn > 148°) from 62.5% of the UpJ-Par fish without a recovery potential. LoJ, but not pugheadedness, had a significant negative effect on fish growth (p < 0.05, ANOVA) and survival rates (p < 0.05, G-test). The findings are discussed in terms of their practical application for quality control and the removal of abnormal fish in commercial hatcheries.

Vibrio alginolyticus is associated with severe infections in marine fish and immunocompromised people. This study investigated the prevalence, genetic typing, associated virulence traits, unveiling resistance genes, and the pathogenicity of V. alginolyticus isolated from sea bream. A total of 200 sea bream (Sparus aurata) were gathered from secluded farms in Port Said, Egypt. Subsequently, clinical, postmortem, and bacteriological analyses, including morphological, culture, biochemical characterization, and PCR-based collagenase gene detection, were performed. The isolated strains were tested for collagenase gene sequencing, antibiogram, pathogenicity, and PCR monitoring of virulence and resistance genes. Herein, V. alginolyticus was found in 14% (28/200) of the collected sea bream, exclusively from the moribund fish. Moreover, the collagenase phylogeny revealed that the tested V. alginolyticus isolates have a distinguished genetic homogeneity with other V. alginolyticus isolates from China, Japan, and the USA. Moreover, the most predominant virulence genes in the tested V. alginolyticus were the collagenase (100%), trh (90.4%), tlh (59.6%), and tdh (21.1%) genes. In this study, 28.8% of the obtained V. alginolyticus strains were multidrug-resistant (MDR) to five classes and encoded bla_TEM, aadA, tetA, bla_OXA, and sul1 genes. Likewise, 15.4% of V. alginolyticus were MDR to four classes and encoded sul1 and tetB genes. As well, 7.7% were MDR to six classes and encoded bla_TEM, tetM, sul1, and bla_OXA genes. Using the cumulative mortality curve, a high mortality rate (87%) was recorded within 7 days in the challenged Tilapia zillii with a virulent V. alginolyticus strain. Concisely, this investigation draws attention to the evolution of MDR V. alginolyticus in sea bream, instructing a health problem. The collagenase, trh, and tlh virulence-related genes and the sul1, bla_TEM, aadA, tetA, bla_OXA, and tetB or tetM resistance genes commonly accompanied the evolving MDR V. alginolyticus in sea bream.

Fish cultivated in a polluted environment usually face complicated disease cases. Pollution is an evitable event in aquaculture that weakens surface immunity, delaying and lowering the immune responses of aquatic animals. In an indoor experiment, Nile tilapia were reared in water polluted with lead (Pb) at a concentration of 51 µg/l for 8 weeks. A trial was conducted to mitigate the immunosuppression using pre-acclimatized Nile tilapia that were subdivided into six groups in which the exposed fish treated with nanocomposite (chitosan-vitamin C-protected nanoparticles (CVC-NPs)) consisted of 1 g of chitosan nanoparticles containing 400 mg vitamin C/kg fish and 200 mg vitamin C/kg fish feed for 1 week. Fish exposed to Pb pollution were immunocompromised as gene expression of immune-related cytokine and antioxidant enzymes significantly declined. Innate immunity was drastically impacted as OBA, phagocytosis and serum antibacterial activity (SAA) showed low values compared to the control fish; meanwhile, exposed fish was challenged against Streptococcus agalactiae and showed a high mortality rate (MR%). Dietary nanocomposite could restore normal immune status, and supplemented fish achieved low MR% with significantly high gene expression of proinflammatory cytokines. It was concluded that adding 200 mg of CVC-NPs/kg fish feed for 1 week could effectively protect Nile tilapia from S. agalactiae, having superiority over the high dose of 400 mg of CVC-NPs.

Totoaba (Totoaba macdonaldi), an ancient fish endemic to the Gulf of California (Sea of Cortez), has faced significant challenges in recent decades. Since 1990, several serious issues have been raised regarding conservation, fisheries, and sustainable aquaculture. In the search for solutions for sustainable Totoaba aquaculture in Mexico, research from natural and social science disciplines has converged to give explanations and proposals. In light of the scientific findings, publications have brought insights into biology, immunology, ecology, nutrition, reproduction, genetics, policies, and social aspects. This review synthesizes and integrates the current state of knowledge across these fields, offering a comprehensive overview of Totoaba research and highlighting prospects, with a particular emphasis on sustainable aquaculture practices and long-term conservation strategies.

This study aims to evaluate the effect of rearing systems, traditional aquaculture system (TAS) and recirculating aquaculture system (RAS), on the ability of Nile tilapia, Oreochromis niloticus, to tolerate chronic hypoxia, growth, hemato-biochemical and oxidative stress biomarkers, and flesh quality parameters. The study consists of two parts, the first involves rearing fish under TAS and RAS in three replicates for 60 days. Nile tilapia fingerlings (initial weight 41.59 ± 5.21 g) were stocked at 4.15 ± 0.61 kg m^–3 in both systems. The second part is a chronic hypoxia test (dissolved oxygen = 1.0 ± 0.2 mg L^–1) in three replicates for 10 days at a stocking density of 7.60 ± 0.36 kg m^–3, followed by a recovery period of 48 h. Fish reared in RAS outperformed (P < 0.0001) TAS in terms of weight gain by 49.57%. Hypoxic fish in both systems exhibit behavioral and morphological changes, which are more rapid in appearance and severe in TAS compared to RAS. Serum cortisol and glucose levels raised significantly (P ≤ 0.05) in both treatments indicating stress, but return to normal levels after the recovery period. Hematological parameters, AST activity, serum proteins, total antioxidant capacity, and superoxide dismutase activity of fish reared in TAS were significantly (P ≤ 0.05) lower in most sampling times. Flesh quality parameters in TAS-reared fish were significantly (P ≤ 0.05) deteriorated than those reared in RAS at all-time intervals. In conclusion, fish reared in RAS experienced superior growth performance, better tolerance to chronic hypoxia, health status, and flesh quality compared to TAS.

Integrated Aquaculture Wastewater Bioremediation Systems (IAWBSs) are crucial for treating nutrient-rich mariculture water. However, there is a lack of detailed information about the functional mechanisms between nitrogen (N) and phosphorus (P) functional genes and the bacterioplankton community in the presence of photosynthetic bacteria (PSB). This study evaluated the connections between N and P functional genes in IAWBSs under the influence of PSB. The results showed significant improvements in effluent quality, with removal efficiencies of 79, 74, 83, 90, and 71% for NO₂⁻−N_, NO₃⁻−N, PO₄³⁻_-P, NH₄⁺−N, and COD_Mn, respectively. Adding PSB enhanced and altered microbial diversity within the system, promoting the abundance of functional genes related to N and P cycling. Notably, genes associated in denitrification (nirK and nirS), ammonification (ureC) and amoB, involved in nitrification, were significantly increased after PSB was added. Furthermore, genes such as phnK, phoD, and phoX, which are involved in P transformation, also showed increased abundance levels. These genes were closely linked to the microbial community distribution, species diversity, and nutrient cycling. Microbial community changes can result in changes in functional gene abundance. This study provides important and novel insights for developing bioremediation strategies for polluted sites. This demonstrates the fundamental relationships between the IAWBSs’ functional units and the distribution of microbial communities under the influence of PSB.

Aquaculture is an interdisciplinary approach that is based on water-food-energy nexus and involves circular bio-based economy concept. This approach has shown immense potential for reduced resource consumption, anthropogenic discharge mitigation, and recycling of nutrients, energy, and agricultural wastes in meeting the global food demands of ever-increasing population. Thus, in this study, we have analyzed the integration of two farming systems, i.e., lettuce (Lactuca sativa) and gulfam fish (Cyprinus carpio), into an agri-aquaculture and compared them with corresponding non-integrated systems or partially integrated systems. The results showed that both lettuce and gulfam fish supported each other as lettuce provided shade and attracted insects for fish feed and fish nitrogenous wastes were utilized by the lettuce for production of green biomass. Consequently, the fully integrated system showed better biomass production with sustainable resource consumption. The gross revenue, cost variable, and net returns of net cost and benefit flow of lettuce and gulfam fish were found considerably high in fully integrated system compared to partially and non-integrated systems. Overall, the net economic return in fully integrated agri-aquaculture systems (PKR 746.57 ± 61.77) was significantly higher than non-integrated (PKR 4181 ± 4.00) and partially integrated system (PKR 326.66 ± 34.26). In brief, the lettuce-gulfam fish agri-aquaculture system could be adopted as a profitable farming system, especially for resource-constrained small-scale farmers as it requires less expense.