Papers by Pedro Pousão-ferreira
Aquaculture, Aug 1, 2012
The present work aims to study the effect of a soluble non-starch polysaccharide (NSP), guar gum ... more The present work aims to study the effect of a soluble non-starch polysaccharide (NSP), guar gum on white sea bream intestinal health through oxidative status and distal intestine morphology evaluation. A control diet was formulated to contain 40% crude protein, 14% crude lipids and 35% pregelatinized maize starch. Three other diets were formulated to include the same levels of all ingredients as control diet except for guar gum, which was included at 4% (diet GG4), 8% (diet GG8) or 12% (diet GG12). Compared to the control, lower catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR) activities and higher SOD, glutathione peroxidase (GPX) and glucose-6-phosphate dehydrogenase (G6PD) activities were observed in the whole intestine of fish fed with diets GG4 and GG12, respectively. Thiobarbituric acid-reacting substances (TBARS) levels were unaffected by diet composition. No morphological alterations in the distal intestine were found among groups. Overall, data on key enzymes of the antioxidant enzymatic defense mechanism suggested that diet-induced reactive oxygen species (ROS) generation is dependent on guar gum inclusion levels and low dietary inclusion of soluble NSP (up to 4%) may have a gut oxidation stress prevention effect.
Aquaculture Nutrition, Feb 1, 2017
This study aimed at evaluating the effects of short-chain fructooligosaccharides (scFOS), xylooli... more This study aimed at evaluating the effects of short-chain fructooligosaccharides (scFOS), xylooligosaccharides (XOS) and galactooligosaccharides (GOS) on growth performance,hepaticmetabolism,gutmicrobiotaanddigestiveenzymesactivitiesof whiteseabreamjuveniles.Fourdietswereformulated:acontroldietwithfishmeal (FM)andplantfeedstuffs(PF)(30FM:70PF)andthreetestdietssimilartocontrolbut supplementedwith10gofscFOS,XOSorGOSperkilodiet,whichwerefedtofish during12weeks.Prebioticshadnoeffectongrowth,feedefficiencyorgutmicrobiota. Plasmatic triglycerides were lower in fish fed XOS than FOS and GOS diets. Malic enzymeactivitywaslowerinfishfedXOSthanFOSdiet.FishfedXOSdiethadlower fatty acid synthetase (FAS), a key lipogenic enzyme and higher alanine aminotransferaseactivities.Fifteendaysafterthestartofthetrial,anenhancementoftotalalkalineprotease,trypsinandlipaseactivitieswasobservedinfishfedprebiotics,butsuch effectdisappearedat12weeks.Inconclusion,scFOS,XOSorGOSseemtohavelimitedapplicabilityinwhiteseabreamfeed.
Animals, Nov 22, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of insects as food and feed, Oct 28, 2022
The effects of black soldier fly (Hermetia illucens) meal (HM) on gut morphology, gut microbial c... more The effects of black soldier fly (Hermetia illucens) meal (HM) on gut morphology, gut microbial community, and humoral immune response was evaluated in meagre (Argyrosomus regius) juveniles. For that purpose, fish with 18.0±0.02 g were fed a control diet (CTR) without HM, and 3 other diets including 10, 20 and 30% HM (diets HM10, HM20 and HM30, respectively), replacing 17, 35 and 52% of fish meal (FM), for 9 weeks. The meagre distal intestine (DI) showed no significant histomorphologic alterations in fold height, lamina propria, submucosa width and cellularity, and enterocytes shape, between dietary treatments. Increasing numbers of eosinophilic granulocytes and intraepithelial leukocytes were observed in fish fed the HM30 diet compared to the CTR and HM10 diets. The mean DI score was higher in meagre fed the HM30 diet, denoting increased overall histomorphological alterations in that group compared to fish fed the CTR diet. No differences in gut bacterial profiles (number of operational taxonomic units, microbiota richness, diversity, and similarity indices) were observed between dietary treatments, either in allochthonous (digesta) and autochthonous (mucosa) communities. Plasma anti-protease activity increased with increasing dietary HM level, while no significant differences were observed in the plasmatic protease, peroxidase, lysozyme and bactericidal activities, nitric oxide production and total immunoglobulins. Overall, and in order to avoid gut histomorphological alterations, an inclusion level up to 10% of HM, corresponding to 17% of FM replacement, is recommended for meagre juveniles.
Antioxidants
This study aimed to determine the effects of dietary inclusion of Tenebrio molitor larvae (yellow... more This study aimed to determine the effects of dietary inclusion of Tenebrio molitor larvae (yellow worms) meal (TM) on meagre fish (Argyrosomus regius) whole-body fatty acids (FA) profile and hepatic and intestine oxidative status. For that purpose, fish were fed for 9 weeks a fishmeal-based diet (control) or diets including 10%, 20%, or 30% TM. With the increase in dietary TM level, whole-body oleic acid, linoleic acid, monounsaturated FA, and n−6 polyunsaturated FA (PUFA) increased while saturated FA (SFA), n−3 PUFA, n−3 long chain-PUFA, SFA:PUFA ratio, n3:n6 ratio, and FA retention decreased. Hepatic superoxide dismutase (SOD), glucose-6-phosphate dehydrogenase (G6PDH), and glutathione reductase (GR) activities increased and catalase (CAT) and glutathione peroxidase (GPX) activities decreased with dietary TM inclusion. Hepatic total and reduced glutathione were lower in fish fed 20% TM. Intestinal CAT activity and oxidized glutathione increased and GPX activity decreased with diet...
Toxins
The dinoflagellate Amyloodinium ocellatum is the etiological agent of a parasitic disease named a... more The dinoflagellate Amyloodinium ocellatum is the etiological agent of a parasitic disease named amyloodiniosis. Mortalities of diseased fish are usually attributed to anoxia, osmoregulatory impairment, or opportunistic bacterial infections. Nevertheless, the phylogenetic proximity of A. ocellatum to a group of toxin-producing dinoflagellates from Pfiesteria, Parvodinium and Paulsenella genera suggests that it may produce toxin-like compounds, adding a new dimension to the possible cause of mortalities in A. ocellatum outbreaks. To address this question, extracts prepared from different life stages of the parasite were tested in vitro for cytotoxic effects using two cell lines derived from branchial arches (ABSa15) and the caudal fin (CFSa1) of the gilthead seabream (Sparus aurata), and for hemolytic effects using erythrocytes purified from the blood of gilthead seabream juveniles. Cytotoxicity and a strong hemolytic effect, similar to those observed for Karlodinium toxins, were obse...
Marine Drugs, 2021
Marine algae are recognised sources of bioactive compounds that have attracted great interest as ... more Marine algae are recognised sources of bioactive compounds that have attracted great interest as nutritional supplements for aquaculture fish. Intensive rearing conditions often expose fish to husbandry-related stressors, rendering fish more susceptible to disease and reducing production yields. The present work evaluated the potential of two marine algae extracts (Fucus vesiculosus and Nannochloropsis gaditana) as nutritional supplements to mitigate stress effects in meagre (Argyrosomus regius) exposed to an acute handling stress (AS). A plant-based diet was used as a control, and three other diets were prepared, which were similar to the control diet but supplemented with 1% of each algal extract or a combination of the two extracts (0.5% each). The effects of supplemented diets on stress biomarkers, antioxidant enzyme activities, and immune response were analysed in fish exposed to AS after 4 weeks of feeding. Supplemented diets did not affect growth performance but the inclusion...
Marine Biotechnology, 2021
Aquaculture is responsible for more than 50% of global seafood consumption. Bacterial diseases ar... more Aquaculture is responsible for more than 50% of global seafood consumption. Bacterial diseases are a major constraint to this sector and associated with misuse of antibiotics, pose serious threats to public health. Fish-symbionts, co-inhabitants of fish pathogens, might be a promising source of natural antimicrobial compounds (NACs) alternative to antibiotics, limiting bacterial diseases occurrence in aquafarms. In particular, sporeforming Bacillus spp. are known for their probiotic potential and production of NACs antagonistic of bacterial pathogens and are abundant in aquaculture fish guts. Harnessing the fish-gut microbial community potential, 172 sporeforming strains producing NACs were isolated from economically important aquaculture fish species, namely European seabass, gilthead seabream, and white seabream. We demonstrated that they possess anti-growth, anti-biofilm, or anti-quorum-sensing activities, to control bacterial infections and 52% of these isolates effectively antagonized important fish pathogens, including Aeromonas hydrophila , A. salmonicida , A. bivalvium , A. veronii , Vibrio anguillarum , V. harveyi , V. parahaemolyticus , V. vulnificus , Photobacterium damselae , Tenacibaculum maritimum , Edwardsiela tarda , and Shigella sonnei . By in vitro quantification of sporeformers’ capacity to suppress growth and biofilm formation of fish pathogens, and by assessing their potential to interfere with pathogens communication, we identified three promising candidates to become probiotics or source of bioactive molecules to be used in aquaculture against bacterial aquaculture diseases.
Aquaculture, 2020
Water quality is critical for fish health in aquaculture production. In flow-through systems, the... more Water quality is critical for fish health in aquaculture production. In flow-through systems, the inflowing water normally requires quality controls and treatments for being supplied from coastal water bodies that can be polluted by nutrients, suspended solids, and microorganisms. Here we assess how seagrass meadows benefit aquaculture systems through the provision of ecosystem services (water filtration, biological control, and regulation of dissolved gasses) in the water reservoir that supplies earthen ponds in an aquaculture system in southern Portugal. In the 1.45-ha reservoir, seagrasses retained daily an estimate of 0.8-1.8 kg d-1 of nitrogen, 0.04-0.07 kg d-1 of phosphorus in their biomass, and 0.7-1.1 kg dw d-1 of suspended total particulate matter, bringing benefits in terms of nutrient and particle removal from the water column. Diel and spatial variation in faecal coliforms levels (Escherichia coli) in the reservoir suggested that seagrasses, in combination with light exposure, may reduce the levels of this pathogen. Furthermore, the seagrassdominated system oxygenated the water through photosynthesis at a faster rate than the respiratory oxygen consumption, maintaining the system above the aquaculture minimum oxygen. This study demonstrates that seagrasses can be used as a nature-based solution to overcome water quality challenges in flow-through aquaculture ponds.
Aquaculture, 2021
Abstract This study aimed to evaluate the effect of including 10%, 20% and 30% of mealworm (Teneb... more Abstract This study aimed to evaluate the effect of including 10%, 20% and 30% of mealworm (Tenebrio molitor, TM) larvae meal (diets TM10, TM20 and TM30, respectively), replacing 25%, 50% and 75% of fishmeal (FM) in a isoproteic (50%) and isolipidic (19%) FM-based diet (CTR) for meagre (Argyrosomus regius). The diets were fed for 9 weeks to triplicate groups of fish with 18.0 g initial body weight and results were evaluated for growth performance; whole-body composition; amino acid (AA) catabolism and digestive enzymes activity; nutrients and chitin digestibility. A digestibility trial was also simultaneously conducted for 48 days. Growth and feed utilization parameters decreased linearly as dietary TM inclusion level increased, while mortality, hepatosomatic and visceral indexes, and AA catabolism enzymes activity were unaffected by the dietary treatments. Whole-body protein was reduced in fish fed TM20 and TM30 diets, with the latter group also having lower energy content than fish fed the CTR diet. The apparent digestibility coefficients (ADC) of dry matter, energy, protein, and AA (except leucine, valine and phenylalanine), decreased as dietary TM inclusion level increased. The lower ADC of protein was related to a linear decrease in trypsin activity. Lipase and total alkaline protease activities were also lower in fish fed the TM30 diet than in the other groups. A quadratic response of total alkaline protease with the increase of dietary TM meal was similar to that observed in the intensity of zymograms bands corresponding to proteases other than trypsin or chymotrypsin-like. Chitin ADC was null and no chitinolytic activity was found in the intestine. Overall, meagre presented a limited capacity to utilize TM, with a 10% TM dietary inclusion already resulting in significant impairment of fish digestive capacity and growth performance, while higher TM dietary levels further negatively affecting fish whole-body composition.
Aquaculture, 2019
In order to demonstrate that IMTA can be profitable and a good alternative to regular semi-intens... more In order to demonstrate that IMTA can be profitable and a good alternative to regular semi-intensive fish mariculture production in earthen ponds three different production treatments with distinct combinations of trophic levels were designed: (i) a combination of fish, filter feeders, phytoplankton and macroalgae, (ii) fish, filter feeders and phytoplankton and (iii) fish, phytoplankton and macroalgae, to evaluate the role of each trophic level within the Integrated Multi-Trophic Aquaculture system (IMTA). Each treatment was carried out under semi-intensive conditions with two replicates, in a total of 6 earthen ponds of 500 m 2 surface and depth of 1.5 m. The results showed that fish, oyster, phytoplankton and macroalgae integrated aquaculture is a healthy sustainable production system for mariculture in the earthen ponds, providing much more fish supply compared with the other two treatments.
Fishes, 2019
Amyloodiniosis is a disease that represents a major bottleneck for semi-intensive aquaculture, es... more Amyloodiniosis is a disease that represents a major bottleneck for semi-intensive aquaculture, especially in Southern Europe. The inefficacy of many of the treatments for this disease on marine fish produced in semi-intensive aquaculture has led to a new welfare approach to amyloodiniosis. There is already some knowledge of several welfare issues that lead to amyloodiniosis as well as the stress, physiological, and immunological responses to the parasite by the host, but no work is available about the influence of fish age on the progression of amyloodiniosis. The objective of this work was to determine if stress, hematological, and histopathological responses are age dependent. For that purpose, we determined the mortality rate, histopathological lesions, hematological indexes, and stress responses (cortisol, glucose, lactate, and total protein) in “Small” (total weight: 50 ± 5.1 g, age: 273 days after eclosion (DAE)) and “Big” (total weight: 101.3 ± 10.4 g, age: 571 DAE) white sea...
Aquaculture Reports, 2019
In this paper we report a case of amyloodiniosis in a sea bass (Dicentrarchus labrax) broodstock ... more In this paper we report a case of amyloodiniosis in a sea bass (Dicentrarchus labrax) broodstock in Portugal. Microscopic examination of gill filaments showed the presence of trophonts while histological observation revealed gills epithelial hyperplasia, hypertrophy and lamellar fusion of secondary lamellae. The amplification and sequencing of the small subunit ribosomal RNA gene allowed the identification of the parasite as Amyloodinium ocellatum. It was also possible to amplify a partial sequence of ribosomal RNA from a Colpodellid, a predator of protists.
Fish & shellfish immunology, 2018
Many studies have assessed the effects of incorporation of plant feedstuffs in fish diets on grow... more Many studies have assessed the effects of incorporation of plant feedstuffs in fish diets on growth performance, whereas few studies have addressed the effects of fish meal replacement by plant protein sources on fish immune parameters. Thus, the aim of this study was to evaluate the effects on immune response of different inclusion levels of carob seed germ meal (CSGM) as partial replacement for fish meal in diets for meagre (Argyrosomus regius) juveniles. Fish were fed four experimental diets with increased CSGM inclusion levels [0% (control), 7.5% (CSGM7.5), 15% (CSGM15) and 22.5% (CSGM22.5)]. After 1, 2, and 8 weeks of feeding fish were sampled to determine haematological profile and several humoral parameters in plasma and intestine. Results showed that dietary inclusion of CSGM did not negatively affect the immune parameters of meagre. In addition, total numbers of red and white blood cells, as well as thrombocytes, lymphocytes, monocytes, and neutrophils counts were not affec...
Journal of Fish Diseases, 2017
Amyloodiniosis represents a major bottleneck for semi‐intensive aquaculture production in Souther... more Amyloodiniosis represents a major bottleneck for semi‐intensive aquaculture production in Southern Europe, causing extremely high mortalities. Amyloodinium ocellatum is a parasitic dinoflagellate that can infest almost all fish, crustacean and bivalves that live within its ecological range. Fish mortalities are usually attributed to anoxia, associated with serious gill hyperplasia, inflammation, haemorrhage and necrosis in heavy infestations; or with osmoregulatory impairment and secondary microbial infections due to severe epithelial damage in mild infestation. However, physiological information about the host responses to A. ocellatum infestation is scarce. In this work, we analysed the proteome of gilthead sea bream (Sparus aurata) plasma and relate it with haematological and immunological indicators, in order to enlighten the different physiological responses when exposed to an A. ocellatum outbreak. Using 2D‐DIGE, immunological and haematological analysis and in response to the...
Fish & Shellfish Immunology, 2016
The aim of this study was to evaluate the effects of short-chain fructooligosaccharides (scFOS), ... more The aim of this study was to evaluate the effects of short-chain fructooligosaccharides (scFOS), xylooligosaccharides (XOS) and galactooligosaccharides (GOS) on immune and hepatic oxidative status, and gut morphology of white sea bream juveniles. Four diets were formulated: a control diet with fish meal (FM) and plant feedstuffs (PF) (30FM:70PF) and three test diets similar to the control but supplemented with 1% of scFOS, XOS or GOS. Dietary prebiotic incorporation did not affect total blood cell counts, hematocrit, hemoglobin, red blood indices or differential white blood cell counts. Fish fed GOS had lower ACH50 and nitric oxide than fish fed control diet. XOS enhanced immune status through the increase in alternative complement pathway (ACH50), lysozyme and total immunoglobulin. The higher activity of glucose 6-phosphate dehydrogenase in fish fed FOS compared to the other dietary groups was the only related antioxidant enzyme affected by prebiotics in the liver. GOS ameliorated the precocious adverse effects of PF based diet on gut histomorphology, as denoted by the lower incidence of histological alterations in fish fed GOS for 15 days. In conclusion, XOS and GOS at 1% might have potential to be used as prebiotics in white sea bream juveniles.
Aquaculture, 2016
Carob seed germ meal (CSGM) was evaluated as ingredient for meagre juveniles' diets. For that pur... more Carob seed germ meal (CSGM) was evaluated as ingredient for meagre juveniles' diets. For that purpose meagre was fed diets with increasing levels of CSGM (75 g kg −1 , 150 g kg −1 and 225 g kg −1) replacing fish meal. Effects on growth performance, feed efficiency, activities of digestive enzymes and key liver amino acid catabolism enzymes were assessed. Digestive tract and liver histology were also evaluated for morphological alterations. Dietary CSGM inclusion up to 225 g kg −1 did not affect growth performance or whole-body composition. Nevertheless, N retention was lower in fish fed the diets with more than 75 g kg −1 CSGM. Digestive enzymes activity decreased with the increase of dietary CSGM. Liver histomorphology and lipid deposition were not affected, while distal intestine showed hyaline droplets of varying sizes with the increase of CSGM in the diets. No signs of inflammation were recorded. Overall, the present study indicates that inclusion of CSGM in meagre juveniles' diets, replacing dietary fish meal as protein source, was suitable up to 225 g kg −1. However, the decrease of digestive enzymes activity, together with decreased protein retention in fish fed the higher levels of CSGM suggest that problems may arise with long-term feeding high levels of CSGM, and this should be confirmed in further studies. Statement of relevance The successful inclusion of carob in aquafeeds may reduce the amount of fish meal used, having the advantage of producing more cost-effective and environmental friendly aquafeeds. Additionally, meagre is as important candidate for Mediterranean aquaculture diversification and if aquafeeds for this species would benefit from using locally produced feedstuffs such as carob, both aspects will contribute to the industry's sustainability.
Communications in agricultural and applied biological sciences, 2013
Aquaculture, 2015
Corn distillers dried grains with solubles (DDGS) is a co-product of corn ethanol production whic... more Corn distillers dried grains with solubles (DDGS) is a co-product of corn ethanol production which biological value is dependent on technological processes and so may be highly variable among production plants. Therefore, two digestibility trials were conducted to evaluate the apparent digestibility coefficients (ADCs) of nutrients and energy of two commercial sources of DDGS and their effects on digestive enzyme activities in European seabass and meagre juveniles. DDGS digestibility was determined based on the substitution of 30% of a reference diet (45%CP; 16%CL) by each test DDGS. ADCs of protein (92-98%), most amino acids (75-99%) and lipids (82-89%) were high while that of energy (58-68%) was low, reflecting the high indigestible fiber content of DDGS. ADCs of nutrients and energy of DDGS were similar in both species, except for some amino acids (lysine, arginine, histidine, isoleucine, tyrosine and aspartic acid) which were higher for seabass than for meagre. Independent of fish species, ADCs of protein and energy were higher in DDGS 1 than in DDGS 2 , whereas ADCs of lipids and most amino acid were not affected by DDGS source. Digestive enzymes activities were species specific: protease activity was higher in meagre while lipase and amylase activities were higher in seabass. For both species, all digestive enzymes activities were higher in mid intestine than in anterior or distal intestine. Overall, it is concluded that corn DDGS is well digested and seem to have high potential for inclusion in diets for seabass and meagre juveniles.
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Papers by Pedro Pousão-ferreira