Laurel Essential Oil Research Articles

Development of a complex antioxidant for stabilization of dressing enriched with omega-3 fatty acids

The solution to the problem of developing a complex antioxidant for the oxidative stabilization of emulsion systems with a high content of ω-3 polyunsaturated fatty acids (PUFAs) is considered. The object of the study is the oxidative stabilization of dressing using a complex antioxidant of plant origin. The ratio of ω-3:ω-6 PUFAs in model samples of the emulsion system was 1:5.46 and 1:2.21. The reasonable range of antioxidant ratios in the complex was substantiated. The ratio of tocopherol extract, garlic and laurel essential oils in the complex antioxidant is 1:1:1, respectively. Over 30 days of storage of the emulsion system model samples stabilized with a complex antioxidant, there is a gradual accumulation of organic acids (from 0.73 % to 0.75 %). The content of primary oxidation products increases for sample No. 2 – from 0.7 to 1.9 mmol ½ O2/kg, for sample No. 3 – from 0.4 to 1.2 mmol ½ O2/kg. The obtained values of physicochemical parameters meet the requirements of regulatory documentation (DSTU 4561). The peculiarity of the obtained results is that the complex antioxidant showed a significant increase in the stability of the emulsion system of high nutritional value, in particular, slowed down the accumulation of organic acids and peroxides. From a practical point of view, the development can effectively stabilize food emulsion systems with a high content of oxidation-labile PUFAs. An applied aspect of the obtained scientific result is the possibility of modeling and developing new formulations of emulsion and individual fat systems with high nutritional value, containing high PUFA concentrations

Essential oils from Cuminum cyminum and Laurus nobilis and their principal constituents: evaluation of antifungal and antimycotoxigenic potential in Aspergillus species.

The antifungal and antimycotoxigenic activities of the essential oils (EO) from Cuminum cyminum and Laurus nobilis, and their respective principal compounds, cuminaldehyde and 1,8-cineole, were evaluated against fungi of the genus Aspergillus: A.carbonarius, A.niger, A.ochraceus and A.westerdijkiae. The antifungal activity was determined by the contact method and the mycelial growth of the fungi was evaluated. Scanning Electron Microscopic (SEM) images were obtained to suggest modes of action of the compounds analyzed. The antimycotoxigenic activity was determined by HPLC. A.carbonarius was completely inhibited by cumin EO (500 µL L-1), by laurel EO and by cuminaldehyde (5000 µL L-1). The cumin EO (500 µL L-1) completely inhibited the growth of A.niger. All the samples inhibited the mycelial growth of A.ochraceus, especially cumin EO and cuminaldehyde (250 µL L-1). A.westerdijkiae was completely inhibited by cumin EO and cuminaldehyde (1000 µL L-1), by laurel EO and 1,8-cineole (10000 µL L-1). A decrease in the production of ochratoxin A (OTA) was observed post-treatment, except in A. ochraceus, only inhibited by laurel EO. SEM images showed morphological changes in fungal structures and spore inhibition post-treatment. The results confirmed the antifungal and antimycotoxigenic effect of EO and their principal constituents on fungi evaluated.

Antioxidant activity evaluation of the combination of oregano (Origanum vulgare) and laurel (Laurus nobilis) essential oil as two natural “chain-breaking” antioxidants by direct measurement of sunflower oil oxidation

Antioxidants are commonly used to reduce oxidative damage in lipids, and essential oils offer natural alternatives with antioxidant properties. This research seeks to determine the antioxidant efficiency of the combination of laurel (laurus nobilis) and oregano (origanum vulgare) essential oils exhibiting a chain-breaking mechanism. To this end, an accelerated oxidation of sunflower vegetable oil was carried out at 60 °C for 28 days, in combination with concentrations of 0.05% w/w (1) and 0.02% w/w (2) of the essential oils. BHT at 0.02% w/w was used as a reference antioxidant. The chemical indicators of oxidation (dienes conjugated, peroxides, anisidine and TOTOX values) and volatiles (2-heptenal Z, 2,4-Decadienal EZ and EE) were determined. While no substantial differences were found between the studied concentrations of the essential oils, a decrease in the protective effect was observed when the concentration of laurel was increased. Interestingly, the antioxidant effect of both oregano and laurel essential oils was observed to be similar to that of BHT. The results suggest that the combination of these essential oils with chain-breaking antioxidant mechanisms might be used as an antioxidant in food.

Use of machine learning methods in predicting the main components of essential oils: Laurus nobilis L.

Laurus nobilis L. is an export plant that contributes to the industry with its medicinal and aromatic properties, as well as the use of its leaves or fruits in the food, pharmaceutical, and cosmetic industries. This study aims to predict the first three main components of bay laurel essential oil with different machine learning methods as a result of GC-MS analysis, taking into account a wide range of parameters used before and after the analysis of the essential oil in pharmacognostic studies. In this study, the K-Means algorithm was used to detect unknown relationships (chemical or physical properties) between the data obtained as a result of the analysis, and Artificial Neural Network (ANN) and Decision Tree machine learning methods were used to perform prediction operations. Based on this, considering the R2 values obtained from ANN analyses, R2 values of 0.9992 for testing, 1 for training, 1 for validation value, and 0.99992 for all were obtained. The ANN model produced results close to the real values with an accuracy rate of 98.97% in predicting the three main components. The Decision Tree algorithm achieved classification with a 96.23% accuracy rate in predicting the three main components. K-Means clustering was performed with an accuracy rate of 97.83% and significant relationships between the features of the Laurus nobilis dataset were detected. This comprehensive study serves as a guide for machine learning research on other essential oils.

Antibacterial and antibiofilm effect of essential oils on staphylococci isolated from cheese - application of the oil mixture in a cheese model

The aim of the research was to examine the antimicrobial and antibiofilm effects of angelica, immortelle, laurel, hyssop, and sage plant dust essential oils (EOs) against isolated strains of Staphylococcus spp. from cheeses, in vitro and in the model of white cheese. MALDI-TOF MS analysis confirmed two Staphylococcus aureus strains and two coagulase-negative, identified as S. saprophyticus and S. warneri. All isolates produce biofilm, where the strains of S. aureus showed slightly better adherence. The main component of angelica EO was β-phellandrene (48.19 %), while α-pinene (20.33 %) were dominant in immortelle EO, in hyssop EO cis-pinocamphone (37.25 %), in laurel EO 1,8-cineole (43.15 %) and in sage EO epirosmanol (26.25 %). The sage EO exhibited the strongest antistaphylococcal activity against all isolates. Synergism was also detected in combination of sage with hyssop or laurel EO. Better antibiofilm activity was confirmed for sage EO compared to hyssop EO. The mixture of sage/laurel EOs reduced the total number of staphylococci in the cheese after 4 days. Results indicate that in vitro applied EOs showed significant antistaphylococcal and antibiofilm activity, while the oil mixture reduced the initial total number of staphylococci.

Preparation and properties of PCL coaxial electrospinning films with shell loaded with CEO and core coated LEO nanoemulsions

During storage and transportation, the reduction of microbial contamination and management of the exudation of fluids from the fish can effectively mitigate spoilage and degradation of fish fillets. In this work, the coaxial electrospinning films loaded with natural plant preservatives, namely laurel essential oil (LEO) and clove essential oil (CEO), were prepared by the coaxial electrospinning method synergistic with nanoemulsion techniques, and the hydrophilic preservation pads were prepared. The morphology of the film fiber is clear, without beads or damage, with fiber diameters falling within the 230–260 nm range. It has a distinct core–shell structure, exceptional thermal stability, and strong antibacterial and antioxidant properties. The core–shell structure of the fiber subtly regulates the release of preservatives and significantly improves the utilization efficiency. At the same time, the synergistic use of two essential oils can reduce the amount while amplifying their effectiveness. The pads significantly slowed down the increase of key indicators of spoilage, such as total viable count (TVC), pH, thiobarbituric acid reactive substances (TBA), and total volatile base nitrogen (TVB-N), during the storage of the fish fillets. Furthermore, the pads effectively slowed down the decline in water-holding capacity, the deterioration of textural qualities, and the negative changes in the microstructure of the fish muscle. Ultimately, the pads notably delayed the spoilage of fish fillets, extending their shelf life from 5 d to 9 d. The efficient utilization of biological preservatives in this film can provide technical support for the development of food preservation materials.

Inhibition of Shewanella putrefaciens biofilm by laurel essential oil and its potential mechanisms

Shewanella putrefaciens (S. putrefaciens) is a major spoilage bacterium in aquatic products and has strong capacity to form biofilm, which contributes to its contamination and persistence in food system. The study aimed to investigate the effect of laurel essential oil (LEO) on biofilm formation of S. putrefaciens by phenotypic analysis and explore its potential mechanisms using RNA sequencing (RNA-seq) analysis. LEO significantly reduced biofilm formation in laboratory media and food broths (oyster juice and sea bass juice), as well as on shrimp surfaces and different food contact surfaces (304 type stainless steel, glass and food-grade silicone). Moreover, LEO also inhibited bacterial motility, decreased extracellular polymeric substances (EPS) contents, and modified biofilm structure. Additionally, RNA-seq analysis identified 229 differentially expressed genes (DEGs), which were involved in transcriptional regulation, multidrug efflux pump transporter, ribosome, cell motility, environmental factors and two-component systems. In conclusion, these findings identify LEO as a potential natural antibiofilm agent for S. putrefaciens and provide insights into its anti-biofilm mechanisms.

Essential Oils of Laurus nobilis L.: From Chemical Analysis to In Silico Investigation of Anti-Inflammatory Activity by Soluble Epoxide Hydrolase (sEH) Inhibition.

Laurus nobilis L. is commonly used in folk medicine in the form of infusion or decoction to treat gastrointestinal diseases and flatulence as a carminative, antiseptic, and anti-inflammatory agent. In this study, the essential oil (EO) composition of wild-grown L. nobilis L. leaves collected from seven different altitudinal locations in the Molise region and adjacent regions (Abruzzo and Campania) was investigated. EOs from the leaves were obtained by hydrodistillation and analyzed by GC-FID and GC/MS, and 78 compounds were identified. The major oil components were 1,8-cineol (43.52-31.31%), methyl-eugenol (14.96-4.07%), α-terpinyl acetate (13.00-8.51%), linalool (11.72-1.08%), sabinene (10.57-4.85%), α-pinene (7.41-3.61%), eugenol (4.12-1.97%), and terpinen-4-ol (2.33-1.25%). Chemometric techniques have been applied to compare the chemical composition. To shed light on the nutraceutical properties of the main hydrophobic secondary metabolites (≥1.0%) of laurel EOs, we assessed the in vitro antioxidant activities based on 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging activity and the reducing antioxidant power by using a ferric reducing power (FRAP) assay. Furthermore, we highlighted the anti-inflammatory effects of seven EOs able to interfere with the enzyme soluble epoxide hydrolase (sEH), a key enzyme in the arachidonic acid cascade, in concentrations ranging from 16.5 ± 4.3 to 8062.3 ± 580.9 mg/mL. Thanks to in silico studies, we investigated and rationalized the observed anti-inflammatory properties, ascribing the inhibitory activity toward the disclosed target to the most abundant volatile phytochemicals (≥1.0%) of seven EOs.

Antimicrobial effects of laurel extract, laurel essential oil, zahter extract, and zahter essential oil on chicken wings contaminated with Salmonella Typhimurium.

This study aimed to evaluate the antimicrobial effects of zahter extract, zahter essential oil, laurel extract, and laurel essential oil on Salmonella Typhimurium inoculated on chicken wings. A total of 10 groups, including eight study groups and two control groups were formed, consisting of zahter extract and zahter essential oil and laurel extract and laurel essential oil in different proportions. In the study, laurel extract at 6.4% and 12.8% concentrations, laurel essential oil at 0.2% and 0.4% concentrations, zahter extract at 0.2% and 0.4% concentrations, and zahter essential oil at 0.2% and 0.4% concentrations were used. The broth microdilution method was used to evaluate the antimicrobial activity of the extract and essential oils on the S. Typhimurium. Minimum inhibitory concentrations of the extracts and essential oils used in the study against S. Typhimurium were determined. The highest inhibitory effect on S. Typhimurium was observed in the 0.4% laurel essential oil group. It was determined that the inhibitory effect increased as the concentration of laurel essential oil increased. In addition, the antimicrobial activity of zahter essential oil is less inhibitory than the laurel extract, laurel essential oil, and zahter extract. According to the results of this study, it has been revealed that extracts and essential oils obtained from zahter and laurel plants, which have been shown to be natural antimicrobial, can be used in foods as an alternative to chemical additives. To develop research results, the applicability of these extracts and essential oils in different foodstuffs should be examined using different ingredients and concentrations.

ANTIMICROBIAL POTENTIAL OF "KAVALGINE" CLAY BASED NOVEL PREPARATION FOR PROPHYLACTIC SKIN CARE

The demand for novel antimicrobial preparations is high in medicine, veterinary, agriculture, etc. However, numerous classical preparations derived from steroids, oligo-/macro- cyclic lactones, and antibiotics possess notable disadvantages: adverse effects on human health, the potential for ecological risks, etc. Moreover, the increase of antibiotic concentrations in environment escalates the multi-drug resistance problem. Therefore, the need of innovations in that scope, and particularly, the search for alternative new natural preparations is very actual. The current paper discusses "Kavalgine” new preparation, developed using natural components: highly mineralized clay obtained during the table salt mining; propolis, laurel essential oil and other bioactive additives. Its effect was successfully tested on model strains of various opportunistic pathogens: Klebsiella pneumonia, Pseudomonas aeruginosa, Salmonella enteritidis, and Staphylococcus aureus.

Bacteriolytic activity of ruminal protozoa is affected by rate and type of common essential oils: Effect of thyme oil

Over the past two decades, research into the effects of essential oils (EOs) on rumen microorganisms as an alternative to antibiotics has intensified. Yet, there are few investigations on rumen protozoa. To evaluate if EOs have antiprotozoal efficacy against rumen protozoa, the present investigation was conducted. Using the potentiality of rumen protozoa to digest 14C-labeled bacteria, the influence of EOs on in vitro protozoal activity was determined. For the study, orange peel, cinnamon, laurel, oleaster, garlic, and thyme essential oils were selected. Control (without essential oil), 500 mg/kg, 1000 mg/kg, and 5000 mg/kg dosages were used. Except for garlic oil, all essential oils showed a notable effect on antiprotozoal activity. The highest antiprotozoal impact was reported at 500 mg/kg and 1000 mg/kg doses of thyme oil, with respective reductions of 89.1% and 84.8% in bacteria degraded by protozoa. Cinnamon and oleaster oils had the strongest antiprotozoal efficacy at a concentration of 5000 mg/kg. At 5000 mg/kg doses of oleaster and cinnamon oils, the quantity of 14C-labeled bacteria degraded by protozoa was reduced by 96% compared to the group that served as the control. In conclusion, orange peel, cinnamon, laurel, oleaster, and thyme oils demonstrated remarkable in vitro antiprotozoal activity; however, more comprehensive research is required to analyse the effects of the EOs used in this study on rumen living groups such as protozoa, bacteria, and yeast and on rumen dynamics.

Revitalizing the hair ends: Formulation and evaluation of the elderflower (Sambucus nigra) hair mask for enhanced hair health

Background: Elderflower (Sambucus nigra) is esteemed for its historical use in traditional medicine and culinary applications, attributed to its rich content of bioactive compounds, including flavonoids, phenolic compounds, and essential oils. Recognizing its potential benefits for skin and hair health, elderflower has found its place in the cosmetic industry. This study ventured into developing and evaluating the elderflower hair mask, an innovative product tailored to nourish and rejuvenate hair ends. Materials and Methods: The formulation of the elderflower hair mask incorporates a blend of lemon and cedar hydrosols, BTMS (behentrimonium methosulfate, cetearyl alcohol), broccoli oil, elderflower powder, grapefruit essential oil, and laurel essential oil. The research encompasses the detailed preparation process and emphasizes the significance of equipment cleansing and disinfection protocols. A notable aspect is the use of freshly milled elderflower powder, ensuring the preservation of its potency. Comprehensive traceability worksheets are employed to meticulously record ingredients, batch numbers, and due dates, thereby ensuring product quality and traceability. The pH of the elderflower hair mask is at 6, harmonizing with the natural pH of healthy hair, thus facilitating effective conditioning without disrupting the structural integrity of the hair. Results: This study illuminated the distinctive attributes of each ingredient within the formulation. Lemon hydrosol contributes cleansing and clarifying properties, while cedar hydrosol offers soothing effects. BTMS demonstrates its prowess in hair conditioning, while broccoli oil aids in moisture retention. Grapefruit essential oil contributes an invigorating aroma, and laurel essential oil is recognized for its potential to promote hair strength and scalp health. Discussion: The elderflower hair mask embodies a holistic approach to hair care by carefully selecting and formulating these ingredients. The pH alignment with the hair’s natural pH underscores its effectiveness in conditioning. This innovative product has the potential to revitalize and nourish hair ends, offering a fusion of traditional wisdom and modern cosmetic science. Further research may delve into the mask’s specific benefits, supporting its role in enhancing hair health and overall well-being. Key words: Elderflower, Cosmetics, Natural ingredients, Hair mask

IN VITRO ANTIFUNGAL EFFECT OF TWELVE ESSENTIAL OILS ON PENICILLIUM EXPANSUM GROWTH

The questionable safety of food spoiled by microorganisms is and should be the subject of attention and investigation. Pathogens such as Penicillium expansum are more difficult to control due to their resistance and ubiquity. Awareness of plant essential oils (EOs) as alternative natural preservatives is increasing because of their significant antimicrobial activity. The aim of this research work was therefore to contribute to this topic with new results. The antifungal activity of twelve EOs was tested in vitro against five strains of Penicillium expansum, using the vapour-phase diffusion method. Three EOs, from bergamot, star anise and rosaline, inhibited colony growth during two-week cultivation with a partial efficacy, all other EOs showed complete (100%) inhibitory activity at a concentration of 625 μL.L-1. These (EOs from clove, cinnamon, cinnamon bark, laurel, lemongrass, peppermint, Mitcham mint, spearmint, and lavender) were included in the second part of the trial, the aim of which was to determine their minimum inhibitory doses (MIDs). In the case of peppermint, Mitcham mint, spearmint and lavender EOs, some strains of P. expansum grew already at a concentration of 500 μL.L-1. Clove EO stopped the fungal growth of two strains at 250 μL.L-1. Laurel EO was 100% effective at MID 250 μL.L-1 throughout the cultivation period. EOs from lemongrass and cinnamon bark had similar efficacy on the strains. Both EOs were able to inhibit one strain at a MID of 125 μL.L-1, cinnamon bark EO inhibited the remaining strains at 250 μL.L-1, lemongrass EO inhibited three strains at 250 μL.L-1 and one at 500 μL.L-1. The lowest MID was recorded for cinnamon EO, which effectively inhibited two strains at 125 μL.L-1, two strains at 62.5 μL.L-1 and one strain even at 31.25 μL.L-1. The sensitivity of the strains used in this study varied according to the EOs used.

Anti-Biofilm Activity of Laurel Essential Oil against Vibrio parahaemolyticus.

Vibrio parahaemolyticus is a primary seafood-associated pathogen that could cause gastroenteritis. It can attach to various surfaces and form a biofilm, which poses serious threats to food safety. Hence, an effective strategy is urgently needed to control the biofilm formation of V. parahaemolyticus. Laurel essential oil (LEO) is used in food, pharmaceutical and other industries, and is commonly used as a flavoring agent and valuable spice in food industries. The potential antibiofilm effects of LEO against V. parahaemolyticus were examined in this study. LEO obviously reduced biofilm biomass at subinhibitory concentrations (SICs). It decreased the metabolic activity and viability of biofilm cells. Microscopic images and Raman spectrum indicted that LEO interfered with the structure and biochemical compositions of biofilms. Moreover, it also impaired swimming motility, decreased hydrophobicity, inhibited auto-aggregation and reduced attachment to different food-contact surfaces. RT-qPCR revealed that LEO significantly downregulated transcription levels of biofilm-associated genes of V. parahaemolyticus. These findings demonstrate that LEO could be potentially developed as an antibiofilm strategy to control V. parahaemolyticus biofilms in food industries.

Effect of xylanase addition and ultrasonic pretreatment on the yield and volatile profile of bay laurel and sage essential oil

In order to increase the yield of essential oils in hydrodistillation of bay laurel and sage, the effect of pretreatment with ultrasound and enzymes (under different conditions of xylanase pretreatment) was studied. The effects of the optimized conditions (concentration of xylanase 0.20 mg/mL in buffer pH=6.5 at 40°C for 4 h) during the enzymatic pretreatment showed that despite the optimization the activity of xylanase did not significantly affect the quantity and quality of essential oils of bay laurel and sage. Ultrasonic pretreatment prior to enzymatic pretreatment with the addition of optimized xylanase resulted in increased yields of dominant compounds (α-thujone 27.42%, β-thujone 12.15%, and camphor 20.94%) in sage essential oil, while in bay laurel the amount of dominant compounds (1,8-cineole 24.65% and α-terpenyl acetate 11.05%) was not significantly increased. Despite minor changes, ultrasonic and enzymatic pretreatment of the plant materials did not significantly affect the chemical composition of the essential oils of bay laurel and sage compared with the control without pretreatment, as confirmed by the Spearman rank test (p < 0.05). The main advantage of ultrasonic extraction is the reduction in pretreatment time. Ultrasonic pretreatment for only 10 min before enzymatic pretreatment resulted in a 50% increase in sage essential oil yield and a 40% increase in bay laurel essential oil yield.

Essential Oils from Mediterranean Plants Inhibit In Vitro Monocyte Adhesion to Endothelial Cells from Umbilical Cords of Females with Gestational Diabetes Mellitus.

Essential oils (EOs) are mixtures of volatile compounds belonging to several chemical classes derived from aromatic plants using different distillation techniques. Recent studies suggest that the consumption of Mediterranean plants, such as anise and laurel, contributes to improving the lipid and glycemic profile of patients with diabetes mellitus (DM). Hence, the aim of the present study was to investigate the potential anti-inflammatory effect of anise and laurel EOs (AEO and LEO) on endothelial cells isolated from the umbilical cord vein of females with gestational diabetes mellitus (GDM-HUVEC), which is a suitable in vitro model to reproduce the pro-inflammatory phenotype of a diabetic endothelium. For this purpose, the Gas Chromatographic/Mass Spectrometric (GC-MS) chemical profiles of AEO and LEO were first analyzed. Thus, GDM-HUVEC and related controls (C-HUVEC) were pre-treated for 24 h with AEO and LEO at 0.025% v/v, a concentration chosen among others (cell viability by MTT assay), and then stimulated with TNF-α (1 ng/mL). From the GC-MS analysis, trans-anethole (88.5%) and 1,8-cineole (53.9%) resulted as the major components of AEO and LEO, respectively. The results in C- and GDM-HUVEC showed that the treatment with both EOs significantly reduced: (i) the adhesion of the U937 monocyte to HUVEC; (ii) vascular adhesion molecule-1 (VCAM-1) protein and gene expression; (iii) Nuclear Factor-kappa B (NF-κB) p65 nuclear translocation. Taken together, these data suggest the anti-inflammatory efficacy of AEO and LEO in our in vitro model and lay the groundwork for further preclinical and clinical studies to study their potential use as supplements to mitigate vascular endothelial dysfunction associated with DM.

Evaluation of the antibacterial activity of essential oil of Laurus nobilis against Pseudomonas syringae pv. phaseolicola and potential biocidal action

Summary With a continuously growing human population on our planet, the chemical burden of our environment is also growing. In addition, the resistance of microorganisms, like bacteria, to widely used chemicals is evident. Therefore, the application of bactericidal products that reduce the risks for development of resistance as well as the environment and human safety is of great benefit. In this work, we have screened the essential oil extracted from plants of Laurus nobilis L. (laurel) grown at the base of the Greek mountain Olympus for its antimicrobial activity against two strains of the Phaseolus vulgaris pathogen, Pseudomonas syringae pv. phaseolicola as well as human pathogenic bacteria (biocidal use). Our results, obtained with established methods, like Well diffusion and Disc diffusion assay, reveal that laurel essential oil is a very effective bacteriostatic and bactericidal agent. Importantly, the activity of laurel essential oil as growth inhibitor of the plant pathogen Pseudomonas syringae pv. phaseolicola is reported for the first time. This opens the field for more extended investigations regarding its use in crop protection. Additionally, the laurel essential oil tested showed significant antibacterial properties against several human pathogenic bacteria, namely Micrococcus luteus, Escherichia coli, Staphylococcus aureus and Bacillus subtilis.

Influence of laurel (Laurus nobilis) essential oil on gut function of Black Sea salmon (Salmo labrax) juveniles.

The present work investigated the effects of dietary incorporation of laurel (Laurus nobilis) essential oil on the zootechnical performance and digestive physiology of juvenile Black Sea salmon (Salmo labrax). In this trial, 15 fiberglass tanks (39 × 39cm square and 33cm high) were used. Forty-five fish (3.52 ± 0.01g) were placed randomly per tank. Fish were fed for 90days with the diet containing 50, 100, 200, or 400mgkg-1 laurel (Laurus nobilis) essential oils, respectively. The work was performed in the recirculating aquaculture system (RAS) operating with freshwater. Fish were manually fed 3% level of live weight during the experiment period. Final weight (FW), weight gain (WG), feed conversion rate (FCR), and specific growth rate (SGR) were not affected by laurel essential oil supplementation. Dietary laurel essential oil (50mgkg-1) affected positively the surface area of fish intestinal villus that required for digestion. Both villus height and villus width were affected positively in fish fed with 50mg laurel essential oil kg-1. While incorporation with 100mg laurel essential oil kg-1 increased the total α-amylase enzyme, 50mg laurel kg-1 increased lipase enzyme. Moreover, 50mg laurel essential oil kg-1 increased lactic acid bacteria (LAB) count in fish. Besides, 50mg laurel essential oil kg-1 reduced the number of total coliform and E. coli.

Effects of Adding Laurel (Laurus nobilis) Essential Oil to the Diet of Tilapia Fish on Growth and Intestinal Histology

The effects of adding laurel oil to the experimental diet on growth performance, biochemical compositions of fish and feeds, sand liver and intestine histology in Nile tilapia (Oreochromis niloticus) juveniles were evaluated. 180 fish (12±0.02 g) were used in the study. They were randomly placed in 12 tanks with a volume of 500 liters, with 15 fish per tank. The commercial laurel oil was added to the diets at 0, 0.3, 0.6, and 1.2%. The fish were fed with experimental diets twice a day as apparent satiation for 60 days. In the current study, weight gain (WG), feed conversion ratio (FCR), specific growth rate (SGR) and survival rates (SR) were statistically similar (p&gt;0.05). While no difference was observed between protein and ash values in the biochemical analysis of fish, lipid values were found to be lower in the 0.3% and 0.6 supplemented groups compared to the control and 1.2% supplemented groups. In addition, there was no statistical difference in protein, lipid, and ash values in the biochemical composition of the feeds. In the study, essential oil components of Laurus nobilis oil such as Linalool, Elemene, Trans-Caryophyllene, Cis-α-Bisabolene, Α-Terpinyl Acetate, Methyleugenol, β-Eudesmol were determined in low levels. The addition of 0.3% laurel oil to the diet did not cause histopathological findings, and it was found to improve liver and intestinal tissues. In conclusion, it is suggested that 0.3% laurel oil addition can be used as a feed additive in tilapia culture, especially considering the data obtained from growth and histological analyzes. Further studies are deserved need to examine the effects of laurel oil on immunity and resistance to various stress factors in other fish.&nbsp;

Physicochemical and Microbiological Properties of Common Carp (Cyprinus carpio) Fillets Marinated with Rosemary and Laurel Essential Oils

ABSTRACT This study aimed to investigate the effects of rosemary and laurel essential oils added into marination formulas of common carp. All analyses were carried out on the 1st, 4th, and 7th days of marination. During marination, TAMB count was in the range of 3.78–6.16 log cfu/g, while TAPB count was 3.62–5.90 log cfu/g, total coliform bacteria count was 0.00–4.86 log cfu/g, LAB count was 3.37–5.06 log cfu/g, and the total yeast and mold count was 3.68–5.61 log cfu/g. The pH values of the samples varied between 3.65 and 5.64. TBARS values were determined between 0.214–0.556 mg MA/kg fish. The differences both in the color values and the textural properties of the samples were significant. When all the data was considered, the marination process with rosemary and laurel essential oils positively affected the microbiological and physicochemical properties of common carp fillets.