Stella Dokou

Ms. Stella Dokou


Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 August 2022 in Frontiers in Veterinary Science
Verified
Journal Article
Open access
Ilias GiannenasIlias Giannenas
Ilias Giannenas
Panagiotis SAKKASPanagiotis SAKKAS
Panagiotis SAKKAS
Georgios PapadopoulosGeorgios Papadopoulos
Georgios Papadopoulos
IMIoannis K Mitsopoulos
Ioannis K Mitsopoulos
ISIoanna Stylianaki
Ioanna Stylianaki
VBVasileios Bampidis
Vasileios Bampidis
Chronic exposure to high ambient temperatures is detrimental to laying hen performance and egg quality. Plant secondary metabolites may alleviate effects, partly due to their antioxidant activities. Herein, we investigated the effects of dietary supplementation with a phytonutrient solution (PHYTO) consisting of a plant extract combination of Scutellaria baicalensis and Curcuma longa on young layers (25–32 wk of age) raised under naturally elevated temperature conditions. Four hundred, 24-wk-old Lohmann hens were allocated in 50 cages and, after a week of adaptation, were offered a diet either containing 2 g/kg of PHYTO or not, for 8 wk. Hen BW was measured at the beginning and end of the trial, and egg production and feed intake were recorded weekly. At week 32, four eggs per cage were collected to determine egg quality characteristics as well as the rate of lipid and albumen oxidation in fresh eggs. At the end of the trial, two hens per cage were blood sampled for assessment of biochemical markers, one of which was euthanized for histopathological evaluation of the liver and intestine and assessment of intestinal histomorphometry. The herbal mixture supplementation significantly increased egg production rate at weeks 28 and 29 and for the overall production period, and feed efficiency at weeks 26–29. In addition, the degree of liver necrosis and microvascular thrombosis was lower (P < 0.05) whereas intestinal villosity was greater in duodenal and jejunal segments (P < 0.05) in the PHYTO compared to the control group. Supplementation also reduced (P < 0.05) blood concentrations of corticosterone, alanine aminotransferase activity, and TBARS, and a reduction in catalase activity was observed. Egg quality characteristics were not affected, except for eggshell thickness, egg diameter, and eggshell breaking strength that were superior in the PHYTO group (P < 0.05). PHYTO supplementation significantly improved egg lipid oxidation status of fresh eggs. In conclusion, supplementation with PHYTO improved laying hen productivity and egg quality, which was associated with an improvement in laying hen thermotolerance.

5 May 2022 in Poultry
Verified
Journal Article
Open access
PDF file
SVStelios Vasilopoulos
Stelios Vasilopoulos
SDStella Dokou
Stella Dokou
Georgios PapadopoulosGeorgios Papadopoulos
Georgios Papadopoulos
Soumela SavvidouSoumela Savvidou
Soumela Savvidou
SCStamatia Christaki
Stamatia Christaki
Ilias GiannenasIlias Giannenas
Ilias Giannenas
The purpose of this trial was to evaluate the effects of Punica granatum L. and Allium cepa L. peels aqueous and cyclodextrin extracts on broiler chicks’ performance and welfare status, as well as on the meat chemical composition and oxidative stability. A total of 120 one-day-old male Ross-308 chicks were randomly allocated to three treatments with four replicate pens (10 chicks per pen). Broiler chicks in the control group were fed typical commercial rations in mash form, based on maize and soybean meal. The rations of the other two treatments were further supplemented with the mixture of Punica granatum and Allium cepa aqueous and cyclodextrin extracts at the level of 0.1% of the feed, respectively. At the end of the trial (day 35), tissue samples were collected for analysis. Body weight (BW), feed intake (FI), average daily gain (ADG) and the feed conversion ratio (FCR) during the period of 1–10 days, 11–24 days, 25–35 days and 1–35 days were evaluated. Litter score, dry matter in litter, pododermatitis and feather score were also assessed at the end of the trial. Data were analyzed with ANOVA using SPSS v25 software. The results showed that BW, FI and FCR values did not differ among the groups. Scoring of pododermatitis, diarrhea, feather, fecal moisture, wooden breast and white stripping did not differ (p ≥ 0.05) among the groups. Punica granatum and Allium cepa aqueous and cyclodextrin extracts favorably affected (p < 0.05) meat composition, color parameters, TBARS and protein carbonyls. Diet supplementation also increased (p < 0.05) ∑n-3 fatty acids as well as ∑n-6 fatty acids in the thigh meat. The cis-4,7,10,13,16,19-Docosahexaenoic acid fatty acids in the breast meat of broilers fed with diets supplemented with the aqueous pomegranate and onion peel extracts were found to be higher (p < 0.05), while these fatty acids in the thigh meat were found increased (p < 0.05) in the cyclodextrin group. Aqueous and cyclodextrin pomegranate and onion peel extracts may provide a promising additive to the broilers diet with functional properties, in the absence of stressful conditions.

25 October 2024 in British Poultry Science
Verified
Journal Article
Open access
Ilias KyriazakisIlias Kyriazakis
Ilias Kyriazakis
SDStella Dokou
Stella Dokou
JTJames Taylor
James Taylor
Ilias GiannenasIlias Giannenas
Ilias Giannenas
EME. Murphy
E. Murphy
1. Shifting to higher welfare systems is expected to increase their environmental impact and mitigation strategies need to be identified. The environmental impacts associated with various broiler production systems (BPS: conventional, higher welfare indoors, free-range or organic) and the characteristics of BPS which contribute to these impacts were investigated via a literature review and meta-analysis. 2. The impact metrics considered were global warming (GWP), acidification and eutrophication potentials, NH3 emissions, land use, water use, energy use (EU) and biodiversity. Due to the paucity of data, analysis was limited to the impacts of the characteristics of the BPS: stocking density (STD), slaughter weight (SW), feed conversion ratio (FCR), on GWP, NH3 emissions and EU. 3. After correction for system boundaries and functional units, no statistical effects of BPS on GWP were found, while higher welfare systems were associated with higher EU. Reduced STD was associated with reductions in GWP and EU. The SW was positively associated with GWP and NH3 emissions, while higher FCR was associated with increased NH3 emissions and EU. 4. Environmental impacts arose from feed-associated activities (>75%). Most of the GWP impacts were associated with land use change (LUC), especially when associated with 'unsustainable' soya. High variation in values for different environmental metrics within BPS indicated a lack of standardisation in the assessment of environmental impact across the industry. 5. The results suggested that practices within a system contributed greatly to the environmental impact of the system. Rather than comparing systems, it may be more productive to focus on improving practices that have the potential to reduce environmental impacts within a system, without compromising animal welfare.

13 June 2023 in Animals
Verified
Journal Article
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INIoannis Nanas
Ioannis Nanas
SDStella Dokou
Stella Dokou
Labrini V. AthanasiouLabrini V. Athanasiou
Labrini V. Athanasiou
EDEleni Dovolou
Eleni Dovolou
TCThomas Chouzouris
Thomas Chouzouris
GAGeorgios S Amiridis
Georgios S Amiridis
Flaxseed and lupin seed were offered as an alternative dietary approach in dairy cows, through the partial substitution of soybean meal. Milk production and fertility traits were investigated. A total of 330 animals were allocated into two groups, treated (n = 176) and control (n = 154). From each group, 30 animals were selected for hematological and cytological studies. The experimental feeding period lasted for 81 days (25 days prepartum and 56 days postpartum). The control ration (group C) contained corn, barley, soybean meal, rapeseed cake, corn silage and lucerne hay; whereas, in the treatment group (group T), 50% of the soybean meal was replaced by an equal mixture of flaxseed and lupins. The two rations were formulated to be isonitrogenous and isoenergetic. Milk samples were analyzed for chemical composition, somatic cell count (SCC) content and total colony forming units (CFU). Blood samples were collected, and serum was analyzed for non-esterified fatty acids (NEFA), acute phase proteins (haptoglobin and serum amyloid) and lipid oxidation indices, namely thiobarbituric-acid-reactive substances (TBARS) and catalase activity. To assess polymorphonuclear neutrophils (PMN) numbers, endometrial samples from each cow were collected on days 21 and 42. No difference was recorded between groups in milk yield (p > 0.05). In multiparous cows, NEFA (mMol/L) concentrations were significantly lower in group T than in group C on day 14 (p > 0.009) and on day 42 (p = 0.05), while no difference was detected in the group of primiparous cows. At all time points, serum TBARS and catalase values were similar in both groups (p > 0.05). Multiparous cows in group T expressed the first postpartum estrus and conceived earlier than cows in group C (p ≤ 0.05). Between days 21 to 42 postpartum, the PMN reduction rate was higher in group T animals (p ≤ 0.05). Acute phase protein levels were in general lower in group T animals, and at specific time points differed significantly from group C (p ≤ 0.05). It was concluded that the partial replacement of soybean meal by flaxseed and lupins had no negative effect on milk yield or milk composition, and improved cow fertility; which, along with the lower cost of flaxseed and lupins mixture, may increase milk production profitability.

16 May 2025 in Foods
Verified
Journal Article
Open access
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VPVasiliki Papanikolopoulou
Vasiliki Papanikolopoulou
Anestis TsitsosAnestis Tsitsos
Anestis Tsitsos
SDStella Dokou
Stella Dokou
SPStergios Priskas
Stergios Priskas
SVSotiria Vouraki
Sotiria Vouraki
Georgios ArsenosGeorgios Arsenos
Georgios Arsenos
The objective of this study was to assess the impact of breed and slaughter hygiene practices on beef quality traits in Northern Greece. A random sample of 159 beef carcasses from three breeds, Aberdeen Angus (AA, n = 38), Holstein (HO, n = 42), and Limousin (LI, n = 40), and crossbred (CR, n = 39) males were used. The chroma, pH, texture, chemical composition, and fatty acid profile were assessed using the Longissimus dorsi muscle. The muscle histomorphometry was assessed using the psoas major samples. Microbiological analyses were conducted on the beef carcasses to evaluate slaughter hygiene. A comparative analysis using ANOVA, Mann–Whitney, and Kruskal–Wallis tests was performed to assess the effects of breed and slaughter hygiene on the meat quality traits. The meat quality differed significantly (p < 0.05) between the breeds. Specifically, the LI beef exhibited higher lightness (L*) values compared to those of the AA and HO beef. The CR breed produced the reddest beef, which differed significantly from the AA and HO beef. The beef yellowness (b*) was higher in the AA breed compared to the other breeds. The AA and CR beef was more tender than the LI beef. The AA beef exhibited the lowest protein and highest fat content, while the LI beef was the leanest. The monounsaturated fatty acid (MUFA) concentrations in the AA beef were 22% higher than those in the HO beef, whereas the HO beef had 23% higher levels of saturated fatty acids (SFAs). The total mesophilic viable counts among the slaughterhouses exceeded the lower acceptable threshold (3.5 log CFU/cm2), indicating inadequate slaughter hygiene practices that could impact beef quality and safety. Globally, this is the first comprehensive study that uniquely combines techniques for assessing beef quality from whole carcasses to individual muscle fibers.

26 November 2024 in Animals
Verified
Journal Article
Open access
PDF file
Anestis TsitsosAnestis Tsitsos
Anestis Tsitsos
SDStella Dokou
Stella Dokou
TCTryfon Chatzimanou
Tryfon Chatzimanou
Ilias GiannenasIlias Giannenas
Ilias Giannenas
Vangelis  EconomouVangelis Economou
Vangelis Economou
Georgios ArsenosGeorgios Arsenos
Georgios Arsenos
Beef is a dominant meat commodity produced mainly from beef cattle breeds. Dairy cattle breeds are reared for milk production, but their calves could be raised to produce high quality meat subject to designated feeding. The objective here was to investigate the role of oregano oil-enriched diets on the quality characteristics of meat produced by Holstein bulls. Fifty Holstein bulls, aged 12 ± 2 months and with an average weight of 365 ± 60 kg, were used. They were equally allocated in two experimental groups (n = 25). One group (group CON) was offered a basal diet and the other (group OREG) the same diet enriched with 50 mg/kg DM of oregano oil, for a period of 90 days. Afterwards, meat samples were subjected to microbiological (1 h after slaughter), physicochemical (1st and 15th day after slaughter), and sensory analyses (15th day after slaughter). The beef of group OREG is characterized with improved color parameters and a lower malondialdehyde (MDA) production rate and content (68.52 ng/g versus 105.91 ng/g, p = 0.01). The sensory evaluation of beef revealed higher scores for group OREG in flavor (3.88 versus 3.17, p = 0.0007) and color (3.87 versus 3.21, p = 0.001), as well as higher nutritional value, which was associated with significantly higher levels of alanine, arginine, aspartic acid, histidine, isoleucine, leucine, lysine, valine, and total amino acids (p < 0.05). Thus, the results suggest that the quality of the meat of Holstein bulls can be improved when they are fed a diet enriched with oregano oil.