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Simple Summary: The aquaculture industry is constantly looking for alternative ingredients to fishmeal and terrestrial-plant feedstuffs. Here, we have studied the effects of the combined administration of Chlorella fusca and ethanol-inactivated Vibrio proteolyticus DCF12.2 in the diet of the thick-lipped grey mullet (Chelon labrosus), a promising candidate species for aquaculture diversification. The combined diet enhanced growth performance, n-3 polyunsaturated fatty acids, and fish lipid quality. Furthermore, the experimental diet increased several metabolic enzymes' activity, as well as the intestinal absorption capacity. It can thus be concluded that the experimental diet composed of C. fusca and V. proteolyticus was suitable for feeding C. labrosus. This study aimed to evaluate the combined effect of dietary Chlorella fusca and ethanol-inactivated Vibrio proteolyticus DCF12.2 (C + V diet) in Chelon labrosus juveniles, highlighting their nutritional, physiological, and morphological effects. The results showed that the combined dietary inclusion of C. fusca and V. proteolyticus significantly enhanced growth performance and feed utilization compared to the control group. The C + V diet increased the fish lipid quality index (FLQ), n-3 polyunsaturated fatty acids, and n-3/n-6 ratio, which might be beneficial in terms of human nutrition. The C + V diet considerably increased carbohydrate metabolic activity by statistically boosting plasma glucose. The dietary inclusion of C. fusca in conjunction with V. proteolyticus increased metabolic enzyme activity as well as intestinal absorption capacity compared to that found in the control group. In conclusion, the experimental diet was suitable for feeding C. labrosus, increasing their growth and the nutritional characteristics of the muscle and intestine, without causing tissue damage. [ABSTRACT FROM AUTHOR]

Given the potential of microalgae as new aquafeed ingredients, this study focuses on using a blend of microalgae, Tisochrysis lutea, Nannochloropsis gaditana, and Scenedesmus almeriensis, as a dietary ingredient for feeding Sparus aurata juveniles. The growth performance, carcass composition, tissue fatty acid profile, and intestinal microbiota were evaluated after a 30 day-feeding period. A microalgae-free diet was used as control, and three experimental diets were formulated containing 5%, 15%, and 25% of the microalgae blend (MB-5%, MB-15%, and MB-25%, respectively). After 7, 15, and 30 days of feeding experimental diets, biological samples were taken. Growth performance and nutrient utilization were not significantly modified at the end of the experiment. Microalgae inclusion tended to decrease body lipids and affected the fatty acid profile, especially MB-25 diet increased DHA levels. Diet MB-25 promoted appropriate microbial diversity, favoring the presence of probiotic bacteria, such as Lactobacillus, and significantly influencing the fatty acid composition and lipid metabolism in fish. In conclusion, using a short pulse of dietary administration of 25% microalgal blend in S. aurata modulates the intestinal microbiota and lipid composition while maintaining growth performance. [ABSTRACT FROM AUTHOR]

Microalgae are commonly referred to as 'unicellular factories' due to their size and their capacity to produce and accumulate valuable biomolecules. The synthesis of a given biomolecule is generally triggered by external stimuli (e.g., light). This work evaluated the effect of different types of water and nutrient sources (freshwater, wastewater, fertilisers, or pig slurry) on the biochemical composition of the microalga Tetradesmus almeriensis produced on a pilot-scale. Overall, significant differences were observed in the biochemical composition of the biomasses (p < 0.05). The biomass produced using freshwater and fertilisers showed potential to be used as food given its high content of essential amino acids, carotenoids (mainly lutein and β-carotene), and PUFAs (C18:2 and C18:3). The microalgae produced using wastewater showed potential applications in the animal feed and agricultural industries. They showed a higher abundance of essential amino acids and carotenoids, including fucoxanthin and lycopene; the latter was only detected when the biomass was produced using secondary wastewater. The biomass produced using pig slurry as the source of nutrients showed potential for being used as animal feed or as an agricultural product given its high content in essential biomolecules and amino acids. The biochemical composition was not only a cause of different microbial diversities but also of the effect of the different composition of the culture medium that trigger different responses of the microalgal cells. • Microalgal biomass was produced using different types of water and nutrients. • The culture medium had a striking effect on their biochemical composition. • The biomass produced using freshwater showed potential for being used as food. • The biomass produced using wastewater showed potential for use in agriculture. • The biomass produced using pig slurry showed potential for use as animal feed. [ABSTRACT FROM AUTHOR]

Considering algae as novel dietary ingredient for aquafeeds, this study evaluates the effects of three algae, Ulva rigida, Crassiphycus corneus (formerly Hydropuntia cornea) and Scenedesmus almeriensis, on non‐specific immune response and fatty acid profile in juvenile Nile tilapia (Oreochromis niloticus) after a short dietary administration period (30 days). U. rigida, C. corneus and S. almeriensis diets (UL‐25, CC‐25 and SC‐25 respectively) included 25% dry algae biomass, whereas an algae‐free diet was used as control. Biological samples were taken at 7, 15 and 30 days. Diet SC‐25 significantly improved respiratory burst, alternative complement (ACH50) and lysozyme activity (p <.05). Regarding tissue fatty acid composition, SC‐25 diet reduced the levels of saturated fatty acid in liver and muscle, while increased levels of C20:3n6 and eicosapentaenoic acid (EPA) in liver, and total n‐3 content, arachidonic acid (ARA), EPA and docosahexaenoic acid (DHA) in muscle (p <.05). UL‐25 and CC‐25 groups showed the lowest levels of ARA in liver but increased levels of monounsaturated fatty acids. In conclusion, the results obtained lead us to consider the use of a short pulse of dietary algae is suited for improving the immune response and modulating the tissue fatty acid composition in this fish species. [ABSTRACT FROM AUTHOR]

Simple Summary: The thick-lipped grey mullet (Chelon labrosus) has good potential for aquaculture diversification in Europe. However, research studies about this species are scarce, particularly focusing on the nutritional attributes of wild and cultivated thick-lipped grey mullets that might help to optimize its feeding regime. In order to determine the nutritional composition of thick-lipped grey mullet juveniles, wild and cultivated specimens were collected and compared. To do so, the liver fatty acids, muscle proximate composition, fatty acids and amino acids were analyzed. The wild specimens had higher levels of polyunsaturated fatty acids and a higher content of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids than the farmed specimens. Furthermore, all the amino acid scores were above 100% compared to the Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO) standard. This study provides new knowledge and contributes to understanding the nutritional attributes of wild and cultured C. labrosus and helps to design diets according to their nutritional demands. The thick-lipped grey mullet (Chelon labrosus) is a nominee fish species for aquaculture diversification in Spain because it is an omnivore and euryhaline species, but limited knowledge about the nutritional attributes of this species is available. This study aimed to characterize the chemical composition of wild and cultured fish. The muscle proximate composition, and fatty acid and amino acid profiles were assessed. The cultivated specimens showed a higher lipid content and lower protein and ash contents compared with the wild specimens. The predominant tissue fatty acids in both the wild and cultivated fish were palmitic acid (16:0), oleic acid (18:1n-9) and docosahexaenoic acid (DHA, 22:6n-3). A higher content of arachidonic acid (ARA, 20:4n-6), eicosapentaenoic acid (20:5n-3) and DHA were detected in the muscle of wild mullets, while the fish supplied with commercial pellets showed higher quantities of monounsaturated fatty acids, and lower quantities of saturated fatty acids and polyunsaturated fatty acids (PUFAs). Regarding PUFAs, n-3 fatty acids were predominant in wild mullets, while n-6 and n-9 were more abundant in farmed fish. In terms of amino acid composition, except for histidine in wild specimens, the amino acid amounts were higher than the FAO/WHO standard. In conclusion, C. labrosus may contribute to improving the dietary intake of highly polyunsaturated n-3 fatty acids, with a benefit to human health, owing to that fact that a 100-g fillet portion of cultivated and wild C. labrosus can provide 770 mg and 1160 mg of EPA and DHA, respectively, which exceeds the 250 mg dietary daily intake recommended by the FAO/WHO. [ABSTRACT FROM AUTHOR]