Effects of rearing density on growth, digestive conditions, welfare indicators and gut bacterial community of gilthead sea bream (Sparus aurata, L. 1758) fed different fishmeal and fish oil dietary levels

In Mediterranean aquaculture, significant advances have been made towards a reduction of marine-derived ingredients in aquafeed formulation, as well as in defining the effect on how environmental factors such as rearing density interact with fish health. Little research, however, has examined the interaction between rearing density and dietary composition on main key performance indicators, physiological processes and gut bacterial community. A study was undertaken, therefore to assess growth response, digestive enzyme activity, humoral immunity on skin mucus, plasma biochemistry and gut microbiota of gilthead sea bream (Sparus aurata, L. 1758) reared at high (HD, 36–44 kg m−3) and low (LD, 12–15 kg m−3) final stocking densities and fed high (FM30/FO15, 30% fishmeal FM, 15% fish oil, FO) and low (FM10/FO3; 10% FM and 3% FO) FM and FO levels. Isonitrogenous and isolipidic extruded diets were fed to triplicate fish groups (initial weight: 96.2 g) to overfeeding over 98 days. The densities tested had no major effects on overall growth and feed efficiency of sea bream reared at high or low FM and FO dietary level. However, HD seems to reduce feed intake compared to LD mainly in fish fed FM30/FO15. Results of digestive enzyme activity indicated a comparable digestive efficiency among rearing densities and within each dietary treatment even if intestinal brush border enzymes appeared to be more influenced by stocking density compared to gastric and pancreatic enzymes. Plasma parameters related to nutritional and physiological conditions were not affected by rearing densities under both nutritional conditions a similar observation was also achieved through the study of lysozyme, protease, antiprotease and total protein determination in skin mucus, however; in this case lysozyme was slightly reduced at HD. For the first time on this species, the effect of rearing density on gut bacterial community was studied. Different response in relation to dietary treatment under HD and LD were detected. Low FM-FO diet maintained steady the biodiversity of the gut bacterial community between LD and HD conditions while fish fed high FM-FO level showed a reduced biodiversity at HD. According to the results, it seems feasible to rear gilthead sea bream at the on-growing phase at a density up to 36–44 kg m−3 with low or high FM-FO diet without negatively affecting growth, feed efficiency, welfare condition and gut bacterial community.info:eu-repo/semantics/acceptedVersio

Yeast-extracted nucleotides and nucleic acids as promising feed additives for European sea bass (Dicentrarchus labrax) juveniles

Nowadays functional ingredients have a significant potential for improving current low fish meal (FM) aquafeed formulation in sustaining growth and enhancing animal robustness for Mediterranean aquaculture. Among them, nucleotides (NT) and nucleic acids (NA) drew attention for their application in the last two decades. NT are organic molecules involved in many life-supporting pathways, and are the building blocks of NA, which stand as genetic repositories. NT are naturally present in organic ingredients, and among them FM is known to be one of the highest NT sources. When this NT source is seriously limited, fish might be under the minimum NT requirements, especially in fast growing life stages of carnivorous species. Hence, a trial on European sea bass juveniles was carried out, testing two dietary FM levels (FM10, FM20 as 10% and 20% FM, respectively) supplemented with 500 mg kg-1 yeast-originate NT or NA dose over 80 days. Thereafter, fish were exposed to one week of sub-optimal thermal and dissolved oxygen condition (30°C and 4.0 mg/L O2) to further explore the effect of NT and NA inclusion on immune response and gut microbiome alteration. At the end of the growth period NT increased feed intake at both FM dietary levels. FM20 combined with NA and NT further improved growth performance, enhancing lipid efficiency and increased anti-inflammatory TGF-b. After sub-optimal environmental conditions both NT and NA exerted prebiotic functions on gut microbiome by promoting beneficial lactic acid bacteria such as Weissella and Leuconostoc. At the same time NT in 10% FM diet increased the abundance of Bacillus taxon. In conclusion, the combination of NT/NA included at 500 mg kg-1 was able to promote growth when included in 20% FM level, assuming higher nutritional NT requirement when combined with 10% FM. On the other hand, NT/NA added in 10% FM upregulate proinflammatory IL-1b and favor beneficial gut bacterial taxa

Different Fish Meal and Fish Oil Dietary Levels in European Sea Bass: Welfare Implications After Acute Confinement Stress

To provide practical feeding management guidelines preceding a stressful episode during farming practices, European sea bass juveniles (initial weight: 72.3 g) were fed for 60-days different fish meal (FM) and fish oil (FO) dietary levels [high (30% FM, 15% FO, FM30/FO15), intermediate (20% FM, 7% FO, FM20/FO7), and low (10% FM, 3% FO, FM10/FO3)] in triplicate conditions. Fish were then fasted for 36 h and exposed to a 2-h acute crowding (80 kg m–3 biomass). Plasma biochemistry, skin mucus parameters and gene expression of stress and immune-related genes were performed before, at 2 and 24 h after crowding. At the end of the trial, the FM10/FO3 group showed lower final body weight, weight gain, and specific growth rate compared to the other treatments. Most of the plasma parameters were mainly affected by crowding condition rather than diet; however, after stress, lactate was higher in the FM30/FO15 group compared to the other treatments. Similarly, protease, antiprotease, peroxidase and lysozyme in skin mucus were mostly affected by crowding conditions, while fish fed FM10/FO3 displayed higher skin mucosal IgM and bactericidal activity against Vibrio anguillarum and V. harveyi. Most of the stress-related genes considered (hsp70 and gr-1 in the brain; hsp70, gr-1 and gr-2 in the head kidney), showed an overall expression pattern that increased over time after stress, in addition, hsp70 in the head kidney was also up-regulated in fish fed FM30/FO15 after stress. Higher plasmatic lactate together with the up-regulation of some stress-related transcripts suggest a higher reactivity to acute crowding of the stress-response mechanism in fish fed high FM and FO dietary levels. Otherwise, the higher skin mucosal IgM and bactericidal activity observed in fish fed FM10/FO3 dietary levels seems to indicate that acute crowding was able to activate a higher pro-inflammatory response in this treatment. Overall, the results of the present study seem to indicate that 10% FM and 3% FO dietary levels might affect stress and immune responses.info:eu-repo/semantics/publishedVersio

Interaction Between Dietary Lipid Level and Seasonal Temperature Changes in Gilthead Sea Bream Sparus aurata: Effects on Growth, Fat Deposition, Plasma Biochemistry, Digestive Enzyme Activity, and Gut Bacterial Community

A 121-day feeding trial was undertaken to test the effects of two dietary lipid levels (16 and 21% L16, L21) in triplicated gilthead sea bream groups (initial weight: 67.5 g) reared at two different water temperatures (high, H 23°C and low, L 17°C) in the same recirculation system but exposed to a switch in temperature after 58 days. Fish kept at H were transferred to L (HL transition, autumn shift), and the fish kept at L were exposed to H (LH transition, summer shift), while continuing to receive the same diet to apparent satiation in each group. At the end of the trial, no significant diet effect on specific growth rate (SGR), feed intake (FI), and feed conversion rate (FCR) were detected in fish exposed to HL transition compared with those exposed to LH transition, while gross lipid efficiency (GLE) and lipid efficiency ratio (LER) were higher in L16. After temperature changes, L16 displayed higher SGR, FI, GLE, and LER, while mesenteric fat index was reduced. After temperature changes, the combined effects of low lipid diet and low temperature conditions resulted in higher pepsin activity, while trypsin, chymotrypsin, and lipase activities were generally higher at high lipid content. The combined effect of diet and temperature did not alter the metabolic plasma profile, except for the observed final higher aspartate aminotransferase (AST) and alkaline phosphatase (ALP) values when combining high dietary lipid (L21) and temperature changes. Different diets showed a significantly different gut microbiome layout, only at high temperature with L16 diet resulting in a higher load of Lactobacillus. On the contrary, no dietary impact on ecosystem diversity was observed, independently from the temperature. In addition, L16 diet in the HL transition favored an increase in Weissella and Bradyrhizobium genera in the gut microbiome, while in the final condition of LH transition, L21 diet favored a significant increase in Streptococcus and Bacillus. According to the results, the utilization of 16% dietary lipid levels in gilthead sea bream should be preferred during seasonal temperature changes in order to optimize feed utilization and gut health.This research was undertaken under the MedAID (Mediterranean Aquaculture Integrated Development) project, which has received funding from the European Union’s Horizon 2020 Research and Innovation Programme, Call H2020-SFS-23-2016, Grant agreement no. 727315 (http://www.medaid-h2020.eu/). MY and NG received support from the Spanish Ministry of Science, Innovation and Universities (MCIU), the State Research Agency (AEI), the European Regional Development Fund (FEDER/ERDF), and project Thermodigest (RTI2018-096134-B-I00) granted to MY

MedAID. WP2. Improving zootechnical performance. Raw data on Gilthead Sea Bream (Sparus aurata) feeding trials

The dataset contains the results of MedAID project in vivo feeding trials performed on Gilthead seabream (Sparus aurata) at University of Bologna facilities. Each feeding trial was focused on studying the interaction between a specific environmental condition (rearing density in one, seasonal temperature changes in another, daily feeding frequencies in another one) in presence of different dietary conditions. The results of the trials were presented in the following papers: 1) “Parma, L., Pelusio, N. F., Gisbert, E., Esteban, M. A., D'Amico, F., Soverini, M., Candela, M., Dondi, F., Gatta, P. P. and Bonaldo, A. (2020). Effects of rearing density on growth, digestive conditions, welfare indicators and gut bacterial community of gilthead sea bream (Sparus aurata, L. 1758) fed different fishmeal and fish oil dietary levels. Aquaculture, 518, 734854”. doi: 10.1016/j.aquaculture.2019.734854; 2) “Pelusio, N. F., Scicchitano, D., Parma, L., Dondi, F., Brini, E., D’Amico, F., Candela, M., Yufera, M., Gilannejad, N., Moyano, F. J., Gatta, P. P. and Bonaldo, A. (2021). Interaction Between Dietary Lipid Level and Seasonal Temperature Changes in Gilthead Sea Bream Sparus aurata: Effects on Growth, Fat Deposition, Plasma Biochemistry, Digestive Enzyme Activity, and Gut Bacterial Community. Frontiers in Marine Science, 8, 549”. doi: 10.3389/fmars.2021.664701; 3) “Busti, S., Bonaldo, A., Dondi, F., Cavallini, D., Yúfera, M., Gilannejad, N., Moyano, F. J., Gatta, P. P. and Parma, L. (2020). Effects of different feeding frequencies on growth, feed utilisation, digestive enzyme activities and plasma biochemistry of gilthead sea bream (Sparus aurata) fed with different fishmeal and fish oil dietary levels. Aquaculture, 529, 735616”. doi: 10.1016/j.aquaculture.2020.735616

Feeding strategies and functional feeds to improve growth and welfare of farmed fish

European Mediterranean aquaculture urges to deepen knowledge on sustainable feeding strategies and additives sparing fish meal and fish oil and adopt new functional feeds to sustain animal welfare and reduce antimicrobials utilization. This thesis investigated fish nutrition and welfare conditions response of commercial relevant species experiencing different feeding strategies and functional feeds. In conclusion, this manuscript explored fish nutrition and physiology insights related to feeding strategies and the pro-health potential of feed additives, developing new and ready to use tools to sustain Mediterranean aquaculture developmentand increase sustainability

Effects of rearing density on growth, digestive conditions, welfare indicators and gut bacterial community of gilthead sea bream (Sparus aurata, L. 1758) fed different fishmeal and fish oil dietary levels.

In Mediterranean aquaculture, significant advances have been made towards a reduction of marine-derived ingredients in aquafeed formulation, as well as in defining the effect on how environmental factors such as rearing density interact with fish health. Little research, however, has examined the interaction between rearing density and dietary composition on main key performance indicators, physiological processes and gut bacterial community. A study was undertaken, therefore to assess growth response, digestive enzyme activity, humoral immunity on skin mucus, plasma biochemistry and gut microbiota of gilthead sea bream (Sparus aurata, L. 1758) reared at high (HD, 36-44 kg m 123) and low (LD, 12-15 kg m 123) final stocking densities and fed high (FM30/FO15, 30% fishmeal FM, 15% fish oil, FO) and low (FM10/FO3; 10% FM and 3% FO) FM and FO levels. Isonitrogenous and isolipidic extruded diets were fed to triplicate fish groups (initial weight: 96.2 g) to overfeeding over 98 days. The densities tested had no major effects on overall growth and feed efficiency of sea bream reared at high or low FM and FO dietary level. However, HD seems to reduce feed intake compared to LD mainly in fish fed FM30/FO15. Results of digestive enzyme activity indicated a comparable digestive efficiency among rearing densities and within each dietary treatment even if intestinal brush border enzymes appeared to be more influenced by stocking density compared to gastric and pancreatic enzymes. Plasma parameters related to nutritional and physiological conditions were not affected by rearing densities under both nutritional conditions a similar observation was also achieved through the study of lysozyme, protease, antiprotease and total protein determination in skin mucus, however; in this case lysozyme was slightly reduced at HD. For the first time on this species, the effect of rearing density on gut bacterial community was studied. Different response in relation to dietary treatment under HD and LD were detected. Low FM-FO diet maintained steady the biodiversity of the gut bacterial community between LD and HD conditions while fish fed high FM-FO level showed a reduced biodiversity at HD. According to the results, it seems feasible to rear gilthead sea bream at the on-growing phase at a density up to 36-44 kg m 123 with low or high FM-FO diet without negatively affecting growth, feed efficiency, welfare condition and gut bacterial community