Effect of dietary supplementation of lauric acid on growth performance, antioxidative capacity, intestinal development and gut microbiota on black sea bream (Acanthopagrus schlegelii)

A feeding trial of eight weeks was conducted to examine the influence of food supplementation with lauric acid (LA) on Acanthopagrus schlegelii (juvenile black sea bream). A 24 percent fish meal baseline diet was created, while the other two diets were generated with dietary supplementation of graded points of LA at 0.1 percent and 0.8 percent, respectively. Each diet was given a triplicate tank with 20 fish weighing 6.22 ± 0.19 g. In comparison with the control group, the weight gain rate, growth rate, as well as feed efficiency of fish fed of 0.1 percent diet of LA were considerably (P < 0.05) greater. The total body and dorsal muscle proximate compositions did not change significantly between groups (P > 0.05). Triglyceride (TG) content was considerably (P < 0.05) greater in the LA-supplemented meals eating group in comparison with the control group. In the group eating LA-supplemented meals, the height of villus and the number of goblet cells/villus were considerably (P < 0.05) larger. The microbial makeup of the gut was also studied. The differences in phyla, class, and family level were not statistically significant (P > 0.05). Firmicutes in the phylum, Betaproteobacteri, Gammaproteobacteria, and Clostridia in the class, and Clostridiaceae in the family were all substantially increased with higher levels of LA supplementation (P < 0.05). According to the findings of this study, an LA-supplemented diet improves fish development, antioxidative capability, gut microbiota and intestinal health.

Sinop İli Su Ürünleri Üretiminin Mevcut Durumu ve Türkiye Su Ürünleri Üretimindeki Yeri

In the present study, the production amount in the last five years (2015-2019) of Sinop province, which is located in the Black Sea Region and a significant part of fisheries production is carried out, was evaluated. For this purpose; Sinop Provincial Directorate of Agriculture and Forestry and TUIK (Turkish Statistical Institute) data were used. There are 2.326 commercial fishermen and 444 fishing boats in Sinop province. In the sea area of Sinop, 5 enterprises still produce culture fish in cages. The 2 potential marine culture areas identified in Sinop have an annual production capacity of 32.430 tons (31 enterprises). In addition, 5 bivalves (4.940 tons/year) and 1.000.000 number/year capacity juvenile fish production facilities are at the project stage. The total fisheries production of Sinop Province in 2019 was 34.620,9 tons, and 1.505 tons were obtained from aquaculture. In addition to these, 3.924 tons of fish processing facilities per year, and 35 tons of fish meal and oil processing facilities per year are operated. 66% of sea fish caught in Sinop are anchovy (Engraulis encrasicolus ponticus), 16% sprat (Sprattus sprattus phalericus), 13% horse mackerel (Trachurus trachurus), 3% bluefish (Pomatomus saltatrix) and 2% consists of other species. The most preferred marine fish by the consumers are anchovy (Engraulis encrasicolus ponticus), horse mackerel (Trachurus trachurus), whiting (Merlangus merlangus), red mullet (Mullus barbatus), bluefish (Pomatomus saltatrix), turbot (Psetta maxima) and bonito (Sarda sarda) and sea bream (Sparus aurata), sea bass (Dicentrarchus labrax) and rainbow trout (Oncorhyncus mykiss) are the culture fish species offered for sale throughout the year.

Influence of diet and feeding strategy on the performance of nitrifying trickling filter, oxygen consumption and ammonia excretion of gilthead sea bream (Sparus aurata) raised in recirculating aquaculture systems

Gilthead sea bream (Sparus aurata) was raised in six individual recirculating aquaculture systems (RAS) whose biofilters’ performance was analyzed. Fish were fed with three different diets (a control diet, a fishmeal-based diet (FM), and a plant meal-based diet (VM)) and with three different feeding strategies (manual feeding to apparent satiation, automatic feeding with restricted ration, and auto-demand feeding). For every combination of diet and feeding strategy, the mean oxygen consumption, ammonia excretion, and ammonia removal rate were determined. Fish fed with the VM diet consumed the most oxygen (20.06 ± 1.80 gO2 consumed kg−1 day−1). There were significant differences in ammonia excretion depending on the protein content and protein efficiency of the diet, as well as depending on feeding strategy, which in turn affected ammonia removal rates. Fish fed by auto-demand feeders led to the highest mean ammonia removal rate (0.10 gN-TAN removed m−2 biofiltration area day−1), while not leading to peaks of high ammonia concentration in water, which preserve fish welfare and growth.

Effective and Low-Maintenance IMTA System as Effluent Treatment Unit for Promoting Sustainability in Coastal Aquaculture

Integrated multitrophic aquaculture (IMTA) is a versatile technology emerging as an ecological and sustainable solution for traditional monoculture aquacultures in terms of effluent treatment. Nevertheless, IMTA is still poorly applied in aquaculture industry due to, among other reasons, the lack of effective, low-investment and low-maintenance solutions. In this study, one has developed a practical and low maintenance IMTA-pilot system, settled in a semi-intensive coastal aquaculture. The optimisation and performance of the system was validated using Ulva spp., a macroalgae that naturally grows in the fishponds of the local aquaculture. Several cultivation experiments were performed at lab-scale and in the IMTA-pilot system, in static mode. The specific growth rate (SGR), yield, nutrient removal, N and C enrichment, protein and pigment content were monitored. Ulva spp. successfully thrived in effluent from the fish species sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) production tanks and significantly reduced inorganic nutrient load in the effluent, particularly, NH4+, PO43− and NO3−. The enrichment of nitrogen in Ulva spp.’s tissues indicated nitrogen assimilation by the algae, though, the cultivated Ulva spp. showed lower amounts of protein and pigments in comparison to the wild type. This study indicates that the designed IMTA-pilot system is an efficient solution for fish effluent treatment and Ulva spp., a suitable effluent remediator.

Myomaker and Myomixer Characterization in Gilthead Sea Bream Under Different Myogenesis Conditions.

The skeletal muscle is formed by multinucleated myofibers originated by waves of hyperplasia and hypertrophy during myogenesis. Tissue damage triggers a regeneration process including new myogenesis and muscular remodeling. During myogenesis, the fusion of myoblasts is a key step that requires different genes’ expression, including the fusogens Myomaker and Myomixer. The present work aimed to characterize these proteins in gilthead sea bream and their possible role in in vitro myogenesis, at different fish ages and during muscle regeneration after induced tissue injury. Myomaker is a transmembrane protein highly conserved among vertebrates; whereas Myomixer is a micropeptide that is moderately conserved but maintains its crucial AxLyCxL motif. myomaker expression is restricted to skeletal muscle, while the expression of myomixer is more ubiquitous. In primary myocytes culture, myomaker and myomixer expression peaked at day 6 and day 8, respectively. During regeneration, the expression of both fusogens and all the myogenic regulatory factors showed a peak after 16 days post-injury. Moreover, myomaker and myomixer were present at different ages, but in fingerlings there were significantly higher transcript levels than in juveniles or adult fish. Overall, Myomaker and Myomixer are valuable markers of muscle growth that together with other regulatory molecules, can provide a deeper understanding of myogenesis regulation in fish.