Antioxidant activity of dietary oregano essential oil and alpha-tocopheryl acetate supplementation in long-term frozen stored turkey meat

Effects of Dietary Supplementation of a Resin-Purified Aqueous-Isopropanol Olive Leaf Extract on Meat and Liver Antioxidant Parameters in Broilers

Olive leaves are byproducts οf the agro-industrial sector and are rich in bioactive compounds with antioxidant properties. They could be supplemented in poultry diets powdered or less frequently as extracts to improve performance, health and product quality. The objective of this study was to investigate the possible beneficial effects of an aqueous isopropanol olive leaf extract-purified through filtration (250-25 µm) and a resin (XAD-4)-when supplemented in broiler chickens' diets, on meat quality parameters, focusing mainly on antioxidant parameters as there is limited published information. For this purpose, four-hundred-and-eighty-day-old broilers were randomly assigned to four dietary treatments: T1 (control: basal diet); T2 (1% olive leaf extract); T3 (2.5% olive leaf extract); T4 (positive control: 0.1% encapsulated oregano oil commercially used as feed additive). At the end of the experimental period (day 42), the birds were slaughtered, and samples from breast, thigh meat and liver were collected for antioxidant parameters evaluation. On day 1, after slaughter, in thigh meat, Malondialdehyde (MDA) was lower in T2 compared to T3, and total phenolic content (TPC) was higher in T2 compared to T3 and T4. Total antioxidant capacity (TAC) was increased in T2 and T4 breast meat compared to the control. In liver, T4 treatment resulted in higher TPC. The lack of dose-dependent effect for olive leaf extract may be attributed to the pro-oxidant effects of some bioactive compounds found in olive leaves, such as oleuropein, when supplemented at higher levels. In summary, it can be inferred that the inclusion of 1% olive leaf extract in the feed of broilers has the potential to mitigate oxidation in broiler meat and maybe enhance its quality.

Effect of oregano oil and cranberry pulp supplementation in finishing pigs on the physicochemical quality of fresh loin during storage

Oregano oil and cranberry pulp supplements were added to the diets of finishing pigs to determine their effects on the meat quality of fresh loins during storage. Two and three levels of oregano oil (250 and 500 mg·kg−1) and cranberry pulp (5, 10, and 20 g·kg−1) were tested, according to a factorial experimental design. The loin meat was vacuum packed and analyzed at 0 (after the 24 h chilling period post slaughter), 23, 45, and 60 d of storage. Samples were repackaged under aerobic conditions after 0 or 23 d and analyzed after 4, 8, and 12 d. Oregano and cranberry supplements did not affect lipid oxidation (microgram of malondialdehyde equivalent per kilogram of meat) during anaerobic or aerobic storage. On day 0, the fatty acid profile of the loin samples demonstrated that the addition of cranberries at a dose of 10 g·kg−1 was associated with a lower percentage of saturated fatty acids (P = 0.04; 42.97% vs. 40.99%) and a trend for a higher percentage of monounsaturated fatty acids (P = 0.06; 47.26% vs. 46.09%). Considering the result obtained, feeding pigs with oregano and cranberry supplements had a limited effect on meat quality parameters measured during storage.

Schemes for enhanced antioxidant stability in frying meat: a review of frying process using single oil and blended oils

Deep-fried meat products are widely popular. However, harmful compounds produced by various chemical reactions during frying have been shown to be detrimental to human health. It is of great necessity to raise practical suggestions for improving the oxidation problem of frying oils and frying conditions in some aspects. Vegetable oils are not as thermally stable as saturated fats, and blended oils have higher thermal stability than single oil. In this review, we discussed the oxidation problems frying oils and meats are subject to during frying, starting from the oil oxidation mechanism, the effects of different oils and fats on the quality of different fried meats under different conditions were concluded to alleviate the oxidation problem, to highlight the necessity of applying blended oils for frying, and effective antioxidants added to frying oils are also introduced, that would provide more convenient and practical options for obtaining higher quality of fried meat products and offer better understanding of the potential of blended frying oils for frying meat products.

Effect of dietary mannan oligosaccharides and fructo-oligosaccharides on physico-chemical indices, antioxidant and oxidative stability of broiler chicken meat

The objective of this present study was to investigate the potentiality of prebiotics (mannan oligosaccharides-MOS and fructo-oligosaccharides-FOS) in replacement of antibiotic growth promoter and their relationship with physico-chemical indices, antioxidant and oxidative stability and carcass traits of broiler chickens meat. Accordingly, 240 day-old broiler chicks of uniform body weight divided in 6 treatment groups with 5 replicate each (5 × 6 = 30) having 8 birds in each replicate. Six corn based dietary treatments were formulated viz. T₁ (control diet), T₂ (T₁ + Bacitracin methylene di-salicylate @ 0.002%), T₃ (T₁ + 0.1% MOS), T₄ (T₁ + 0.2% MOS), T₅ (T₁ + 0.1% FOS), and T₆ (T₁ + 0.2% FOS). Significant (p < 0.05) increase in cut up part yields (%) and reduction in cholesterol and fat content in T₄ (0.2% MOS) group. The water holding capacity (WHC) and extract release volume (ERV) were increase (p < 0.05) in 0.1 or 0.2% MOS supplemented group. DPPH (1, 1-diphenyl-2-picrylhydrazy) was higher (p < 0.05) and lipid oxidation (free fatty acid and thio-barbituric acid reactive substances) was lower (p < 0.05) in T₄ group. The standard plate count (SPC), staphylococcus and coliform counts were decreased (p < 0.05) in T₃ or T₄ group. Thus, it can be concluded that mannan oligosaccharides (MOS) may be incorporated at 0.2% level in diet for improved physico-chemical indices, antioxidant and oxidative stability and carcass characteristics of broiler chickens meat and it may be suitable replacer of antibiotic growth promoter.

Cooked broiler meat quality affected by different Mediterranean medicinal plants in the diet

Objective

This study was conducted to investigate the effects of adding oregano (Origanum syriacum L.) and germander (Teucrium polium L.) to poultry diets individually and/or in combination: i) on cooked chicken meat quality and storage stability, ii) to compare this effect with those of the synthetic antioxidant butylated hydroxyanisole (BHA) and with the normal basic diet (Control: without supplements).

Methods

Broilers (140 birds) were raised for 21 days and then equally divided into five different treatment groups of 28 birds each. The dietary treatments were as follows: i) control; ii) germander (GER, 1.5%); iii) oregano (ORE, 2.5%); iv) combination of GER and ORE (CM, 1.5%, and 2.5%); v) BHA (0.02%). Meat patties from the five treatments were prepared, cooked, and stored at 4°C prior to analysis. During storage, samples were measured for thiobarbituric acid-reactive substances (TBARS) and total carbonyl levels at 0, 4, and 7 days. In addition, cooked thigh meat was prepared separately to evaluate cooking loss and sensory attributes.

Results

The CM dietary treatment showed the highest antioxidant effect, with decreasing TBARS values (breast and thigh meat) throughout the storage time (4 to 7 days). Furthermore, ORE showed a higher antioxidant effect, decreasing the rancidity development (TBARS values), compared to the GER during the storage period (days 0 to 7). The anti-carbonyl effect of the CM supplement was the highest among all treatments from day 0 to 7. Generally, the antioxidant effect of GER was lower compared to that of ORE and BHA alone. The CM treatment most significantly decreased off-odor and rancidity development, with the lowest oxidation odor scores.

Conclusion

The results indicate that the combination of oregano and germander in the diet of boilers improves meat quality and prolongs shelf life.

Plant Feed Additives as Natural Alternatives to the Use of Synthetic Antioxidant Vitamins on Yield, Quality, and Oxidative Status of Poultry Products: A Review of the Literature of the Last 20 Years

Scientific evidence demonstrates that plant feed additives (PFA) can be a viable alternative to synthetic antioxidant vitamins in poultry nutrition. PFA are represented by plants, essential oils, plant extracts, and by-products from herbal or crop processing. The use of PFA in the feed industry has increased in recent years as their biologically active compounds (polyphenols) have demonstrated antimicrobial and antioxidant effects in food-producing animals. However, few trials have directly compared the effects of PFA with synthetic vitamins. After a systematic literature review of studies comparing the effects of PFA and synthetic vitamins on poultry products in the last 20 years (2000–2020), a total of 44 peer-reviewed articles were included in the present work. A positive effect of PFA on poultry products’ oxidative stability during storage, organoleptic characteristics, and fatty acids profile has been observed without a specific impact on their performances. The effects of PFA are variable but often similar to those of vitamin E, suggesting the opportunity for a partial substitution of the latter in poultry diets.

In vitro and in vivo evaluation of thyme (Thymus vulgaris) essential oil as an alternative for antibiotic in quail diet1

The thyme (Thymus vulgaris) essential oil was assessed as antibiotic growth promoter replacement in quail chick diet and in vitro test. In total, 250-d-old Japanese quail chicks (mixed sex) were allocated into 5 dietary treatments of 5 replications (6 females and 4 males in each cage with the size of 40× 90× 25 cm) under a completely randomized design. The dietary treatments were included the control diet, control diet without any additive, control diet plus 100 ppm flavophospholipol as an antibiotic growth promoter, control diet plus 200 ppm TVE, control diet plus 300 ppm TVE, and control diet plus 400 ppm T. vulgaris essential (TVE) oil. Feed intake, BW gain, feed conversion ratio (FCR), organs weight, morphology of intestine, serum lipids, and microbial population were measured on day 35. Lipid oxidation of stored muscle tissue was measured by TBARS test. GC-MS assay, DPPH method, and well diffusion method were evaluated for determination of components, antioxidant, and antimicrobial properties, respectively. FCR improved significantly in 400 ppm TVE compared with 200 and 300 ppm TVE (P < 0.05). The serum triglyceride decreased significantly in both sexes receiving 400 ppm TVE compared with control. Villi height increased significantly in duodenum accompanied by decreasing crypt dept at all TVE levels compared with control and antibiotic. The breast muscle tissue of quail fed on 300 and 400 ppm TVE reduced the rate of oxidation during refrigerated storage compared with control. Thymol was the main component (35.40%) of the thymus oil. The considerable antioxidant activity of TVE was identified by IC50 of 58.48 µg/mL. Moreover, zones of growth inhibition of Gram-positive bacteria and Escherichia coli were numerically greater in different doses of TVE than antibiotics. Therefore, The TVE is suitable alternative component for antibiotic growth promoters by dosing consideration. However, it is possible that antibiotic resistance would increase for these natural compounds along the time.

EFFECT OF TWO CHEMOTYPES OF OREGANO ESSENTIAL OIL ON BROILER PERFORMANCE, NUTRIENT BALANCE, AND LIPID PEROXIDATION OF BREAST MEAT DURING STORAGE

Abstract This study evaluated the functional effects of two chemotypes of oregano essential oil (OEO): Lippia Origanoides (LO) and a comercial product Synergy Essence (SE). Broilers were randomly assigned to one of eight dietary treatments: 1) Basal diet (BD); 2) BD+ antibiotic growth promoters (AGP) (bacitracin 50g/ton); 3) BD+LO125 (125g/ton); 4) BD+LO250 (250g/ton); 5) BD+LO500 (500g/ton); 6) BD+SE125 (125g/ton); 7) BD+SE250 (250g/ton); 8) BD+SE500 (500g/ton). At the time of slaughter (42 d), five birds per treatment were slaughtered. A portion of the breast was minced and stored at -4 ºC for 3, 6, and 9 days. Lipid peroxidation was determined by measuring of malondialdehyde (MDA), data were analyzed as a completely randomized design with a factorial arrangement of treatments (8x4). Broilers fed SE250 had greater average daily gain (ADG) compared to broilers fed BD (P<0.05). Broilers fed LO500 had greater (P<0.05) organic matter digestibility than the ones fed BD. As days of storage increased, MDA concentration increased (P<0.05). Broilers fed SE500 had lower (P<0.05) MDA concentration than those fed BD and AGP. These data indicate that birds fed OEO grow faster than those fed a BD, similar to birds fed AGP. Some of these responses are possibly explained by increased digestibility and energy utilization. In addition, providing OEO from SE at 500g/ton resulted in lower lipid peroxidation in ground breast meat throughout the tested storage time.

Thymol as natural antioxidant additive for poultry feed: oxidative stability improvement

Antioxidant are regularly included in poultry feed as protection from deterioration during storage. Recently the interest for the use of natural phytochemicals in animal diets has been increased. Thymol (THY) has been proven to be an effective antioxidant for extending broiler meat quality during storage with similar action to the widely used butylated hydroxytoluene (BHT). This study evaluates whether THY can also have a protective effect on the feed mash by assessing its antioxidant potential and related changes in fatty acid (FA) balance. Feed mash was assigned to 1 of 4 treatments, control (CON, no additive), vehicle (VEH, ethanol 96%), BHT (400 mg BHT /kg feed) and THY (400 mg THY /kg feed). Three replicates of each treatment were taken after 0, 30, and 60 d of storage at room temperature (23 ± 3°C) and relative humidity (40 ± 5%). Peroxide value (PV), titratable acidity (TA) and FA relative composition were determined. As expected, there were no treatment effects on those variables at 0 d of storage. However, higher PV values were detected in the CON and VEH groups after 30 and 60 d of storage in comparison to the THY and BHT treated samples (CON = VEH > THY = BHT). While a slight increase was also observed in TA through storage time, no particular treatment effects were detected. Relative FA composition changed with storage time only in the CON and VEH group which had a decrease in polyunsaturated fatty acids and an increase in saturated FA. No changes were detected in the Thy and BHT treated feeds. The results suggest a similar THY and BHT protective effect on feed mash lipid oxidation. Thus, THY could be considered as a useful natural alternative to help sustain quality of poultry feed.

Biological Activities of Three Essential Oils of the Lamiaceae Family

Herbs and spices have been used since ancient times to improve the sensory characteristics of food, to act as preservatives and for their nutritional and healthy properties. Herbs and spices are generally recognized as safe (GRAS) and are excellent substitutes for chemical additives. Essential oils are mixtures of volatile compounds obtained, mainly by steam distillation, from medicinal and aromatic plants. They are an alternative to synthetic additives for the food industry, and they have gained attention as potential sources for natural food preservatives due to the growing interest in the development of safe, effective, natural food preservation. Lamiaceae is one of the most important families in the production of essential oils with antioxidants and antimicrobial properties. Aromatic plants are rich in essential oils and are mainly found in the Mediterranean region, where the production of such oils is a profitable source of ecological and economic development. The use of essential oils with antimicrobial and antioxidant properties to increase the shelf life of food is a promising technology, and the essential oils of the Lamiaceae family, such as rosemary, thyme, and sage, have been extensively studied with respect to their use as food preservatives. Regarding the new applications of essential oils, this review gives an overview of the current knowledge and recent trends in the use of these oils from aromatic plants as antimicrobials and antioxidants in foods, as well as their biological activities, future potential, and challenges.

Supplementing oregano essential oil to boar diet with strengthened fish oil: Effects on semen antioxidant status and semen quality parameters

Previous research has shown benefits of dietary fish oil supplementation on semen quality of boars. However, little is known about how antioxidant protects lipid peroxidation on spermatozoa from n-3 polyunsaturated fatty acid (PUFA) addition. This study evaluated the effect of oregano essential oil (OEO) supplementation on semen antioxidant status and semen quality in boars fed a diet enriched with fish oil. Thirty-four mature boars of proven fertility, received daily 2.5 kg basal diet top-dressed with 45 g soybean oil and 15 g fish oil to meet the n-3 PUFA requirement of spermatozoa, randomly allocated to one of four groups supplemented with 100 mg α-tocopheryl acetate kg^-1 (control), or 250 or 500 or 750 mg OEO kg^-1 for 16 weeks. Semen was collected at weeks 0, 8, 12 and 16 for measurements of sperm production, motion characteristics, sperm α-tocopherol content, antioxidant enzyme activities, reactive oxygen species (ROS), DNA damage (8-hydroxydeoxyguanosine, 8-OHdG), lipoperoxidation (malondialdehyde, MDA) and seminal total antioxidant capacity (TAC). Sperm production and motion characteristics were similar (p > .05) among groups throughout the experimental week 16, but increased (p < .01) with experimental week. Although higher α-tocopherol content and superoxide dismutase (SOD) activities were in OEO group spermatozoa, feeding diet with 500 mg/kg OEO resulted in elevation in seminal TAC, decrease in sperm ROS, MDA and 8-OHdG than control group (p < .05). Overall, these results support the view that oregano essential oil has a positive effect on antioxidant capacity in boar when used fish oil.

Oregano Essential Oil as an Antimicrobial and Antioxidant Additive in Food Products

Food consumers and industries urged the need of natural alternatives to assure food safety and quality. As a response, the use of natural compounds from herbs and spices is an alternative to synthetic additives associated with toxic problems. This review discusses the antimicrobial and antioxidant activity of oregano essential oil (OEO) and its potential as a food additive. Oregano is a plant that has been used as a food seasoning since ancient times. The common name of oregano is given to several species: Origanum (family: Lamiaceae) and Lippia (family: Verbenaceae), amongst others. The main compounds identified in the different OEOs are carvacrol and thymol, which are responsible for the characteristic odor, antimicrobial, and antioxidant activity; however, their content may vary according to the species, harvesting season, and geographical sources. These substances as antibacterial agents make the cell membrane permeable due to its impregnation in the hydrophobic domains, this effect is higher against gram positive bacteria. In addition, the OEO has antioxidant properties effective in retarding the process of lipid peroxidation in fatty foods, and scavenging free radicals. In this perspective, the present review analyzes and discusses the state of the art about the actual and potential uses of OEO as an antimicrobial and antioxidant food additives.

The effect of oregano essential oil on microbial load and sensory attributes of dried meat

BACKGROUND

Microbial load can be controlled using either synthetic or natural preservatives. Particular interest has been focused on the potential application of plant essential oils as safer additives for meat. However, there is no published research on the use of essential oils during the meat drying process. This study was focused on enhancing the meat drying process by using oregano essential oil (OEO) to inhibit the growth of bacteria and thus obtain a value-added dried meat product. The sensory response from assessors is presented.

RESULTS

It was found that the application of OEO in meat was effective in inhibiting Salmonella enteritidis and Escherichia coli. After 6 h of drying at 55 °C, 2 mL (0.038 mL L^-1 air) and 1.5 mL (0.028 mL L^-1 air) of OEO were considered as the minimal inhibitory concentrations (MICs) against S. enteritidis and E. coli respectively. Samples treated with 0.75 mL of OEO were more attractive for consumption compared with the control; at a higher concentration of OEO, the sensory quality of the food was affected.

CONCLUSION

A value-added dried meat product obtained by using OEO to enhance food safety received an acceptable sensory response from consumers. © 2016 Society of Chemical Industry.

Effects of plant extracts and essential oils as feed supplements on quality and microbial traits of rabbit meat

The effects of dietary supplementation of onion, cranberry,  strawberry and essentials oils on meat quality were analysed. Five groups of 48 Grimaud female weaned rabbits received the supplemented or the control ration; the experimental unit was a cage of 6 rabbits. Each experimental diet contained 10 ppm of added active ingredients.  Rabbits were fed with the experimental diets for 4 wk before determining slaughter and carcass traits and determining the pH at 1 and 24 h post mortem (pHu) of the <em>Longissimus dorsi</em> (LD) and the <em>Biceps femoris</em> (BF) muscle, left and right, respectively. Cooking loss, drip loss and L*, a* and b* color parameters were obtained of the right<em> </em>LD and for ground meat and antioxidant status (TBARS, DNPH, Folin Ciocalteu). Only the pHu of the LD muscle for the strawberry supplemented group was significantly lower when compared to the control group (P=0.04). However, we note that for the pH of the LD, the average was less than 6 for the meat of animals who received a diet enriched in polyphenols, compared to the control group. Plant extract supplementation did not influence meat quality traits, growth performance or oxidative stability. But under aerobic and anaerobic conditions, our results indicate that diet supplementation with extracts rich in polyphenols, especially with essential oils, had a small bot sporadic positive effect in reducing bacterial microflora compared to the control group (P&lt;0.05). In conclusion, plant extracts and essential oils can be used in a rabbit diet without adverse effects on performance and meat quality traits. This effect could be optimized by investigating higher doses.

Effect of Oregano Essential Oil (Origanum vulgare subsp. hirtum) on the Storage Stability and Quality Parameters of Ground Chicken Breast Meat

A study was conducted to investigate the effect of oregano essential oil on the oxidative stability and color of raw and cooked chicken breast meats. Five treatments, including (1) control (none added); (2) 100 ppm oregano essential oil; (3) 300 ppm oregano essential oil; (4) 400 ppm oregano essential oil; and (5) 5 ppm butylated hydroxyanisole (BHA), were prepared with ground boneless, skinless chicken breast meat and used for both raw and cooked meat studies. For raw meat study, samples were individually packaged in oxygen-permeable bags and stored in a cold room (4 °C) for 7 days. For cooked meat study, the raw meat samples were vacuum-packaged in oxygen-impermeable vacuum bags and then cooked in-bag to an internal temperature of 75 °C. After cooling to room temperature, the cooked meats were repackaged in new oxygen-permeable bags and then stored at 4 °C for 7 days. Both raw and cooked meats were analyzed for lipid and protein oxidation, volatiles, and color at 0, 3, and 7 days of storage. Oregano essential oil significantly reduced (p < 0.05) lipid and protein oxidation, and improved color stability of raw and cooked meat. However, oregano oil at 400 ppm showed the strongest effect for all these parameters. Hexanal was the major aldehyde, which was decreased significantly (p < 0.05) by oregano oil treatment, in cooked meat. Overall, oregano essential oil at 100–400 ppm levels could be a good preservative that can replace the synthetic antioxidant in chicken meat.

Microbial spoilage, quality and safety within the context of meat sustainability

Meat is a nutrient-dense food that provides ideal conditions for microbes to grow and defines its perishable nature. Some organisms simply spoil it while others are a threat to our health. In either case, meat must be discarded from the food chain and, being wasted and consequently an environmental burden. Worldwide, more than 20% of the meat produced is either lost or wasted. Hence, coordinated efforts from farm to table are required to improve microbial control as part of our effort towards global sustainability. Also, new antimicrobial systems and technologies arise to better fulfill consumer trends and demands, new lifestyles and markets, but for them to be used to their full extent, it is imperative to understand how they work at the molecular level. Undetected survivors, either as injured, dormant, persister or viable but non-culturable (VBNC) cells, undermine proper risk evaluation and management.

EssOilDB: a database of essential oils reflecting terpene composition and variability in the plant kingdom

Plant essential oils are complex mixtures of volatile organic compounds, which play indispensable roles in the environment, for the plant itself, as well as for humans. The potential biological information stored in essential oil composition data can provide an insight into the silent language of plants, and the roles of these chemical emissions in defense, communication and pollinator attraction. In order to decipher volatile profile patterns from a global perspective, we have developed the ESSential OIL DataBase (EssOilDB), a continually updated, freely available electronic database designed to provide knowledge resource for plant essential oils, that enables one to address a multitude of queries on volatile profiles of native, invasive, normal or stressed plants, across taxonomic clades, geographical locations and several other biotic and abiotic influences. To our knowledge, EssOilDB is the only database in the public domain providing an opportunity for context based scientific research on volatile patterns in plants. EssOilDB presently contains 123 041 essential oil records spanning a century of published reports on volatile profiles, with data from 92 plant taxonomic families, spread across diverse geographical locations all over the globe. We hope that this huge repository of VOCs will facilitate unraveling of the true significance of volatiles in plants, along with creating potential avenues for industrial applications of essential oils. We also illustrate the use of this database in terpene biology and show how EssOilDB can be used to complement data from computational genomics to gain insights into the diversity and variability of terpenoids in the plant kingdom. EssOilDB would serve as a valuable information resource, for students and researchers in plant biology, in the design and discovery of new odor profiles, as well as for entrepreneurs—the potential for generating consumer specific scents being one of the most attractive and interesting topics in the cosmetic industry.

Database URL: http://nipgr.res.in/Essoildb/

Effects of dietary rosemary, rosemary volatile oil and vitamin E on broiler performance, meat quality and serum SOD activity

1. The current study was conducted to evaluate the effects of dietary supplementation with vitamin E (as alpha-tocopherol acetate), dried rosemary leaves and rosemary volatile oil on the performance, meat quality (measured as sensory variables, pH, colour, malondialdehyde (MDA) level, and bacteria count) and serum superoxide dismutase (SOD) activity in broilers fed on maize-soybean meal based diets. 2. A total of 800 broiler chicks were randomly allocated to 8 dietary treatments, which were set up with 1 control group and 7 experimental groups. The control group (VitE1) was given a basal diet including 50 mg/kg alpha-tocopherol acetate, while the experimental groups were given 5 x 7 g/kg rosemary plant (R1), 8 x 6 g/kg plant (R2), 11 x 5 g/kg plant (R3), 100 mg/kg plant oil (RO1), 150 mg/kg plant oil (RO2), 200 mg/kg plant oil (RO3) or 200 mg/kg alpha-tocopherol acetate (VitE2). 3. Although there were no statistical differences observed for feed consumption, other performance variables including live weight gain, feed efficiency and carcase yield were significantly affected. The addition of rosemary volatile oil had more effect on the performance variables than did the rosemary plant itself. 4. As a measure of meat shelf life, TBA analyses were performed on the meat samples on d 1, 3 and 5 after culling. Meat MDA levels of groups fed diets with rosemary and rosemary volatile oil were significantly lower than that of groups fed diets containing alpha-tocopherol acetate alone. 5. Significant differences were also seen between the control and experimental groups for meat colour and meat pH values as well as for sensory analyses. 6. Microbiological analyses conducted at the end of the experiment showed that E. coli counts were significantly reduced in meat samples from the experimental groups. 7. In conclusion, dietary supplementation with rosemary and its volatile oil improved broiler meat quality. Moreover growth performance was positively affected by the rosemary volatile oil supplementations.

Dietary strategies to improve nutritional value, oxidative stability, and sensory properties of poultry products

Consumers demand both safer and more nutritious food products exempt of non-natural origin preservatives or other food additives. In this frame, products with lower fat content and/or a higher ratio in unsaturated fatty acids, especially n-3 fatty acids, are desired because these lipids can help prevent the development of cardiovascular and inflammatory pathologies. The intake of meat products is of interest because they are an excellent source of vitamins and minerals. In addition, the shelf-life of meat products can be extended by the presence of natural antioxidants coming from different sources such as plant extracts. Therefore, different strategies have been studied to improve the nutritional value, oxidative stability, and sensory characteristics of meat products and eggs through different mineral and natural dietary supplements. In comparison to other strategies, dietary supplements present the advantage that first the living animals may efficiently distribute the compounds throughout the tissues and second, the dietary supplementation is safer because the resulting enriched meat products and eggs ensure tolerable amounts in humans. Poultry meats and eggs are widely consumed and their fatty acid profile and tocopherol content can be easily modified through different dietary strategies thus being excellent models to improve their nutritional value and oxidative stability.

Essential oil of Myrtus communis L. as a potential antioxidant and antimutagenic agents

The present study describes DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and antimutagenic properties of the essential oil of myrtle (Myrtus communis L.). Plant samples were collected from the two distant localities (southernmost and northern point) of the Montenegro coastline. Chemical profiles of the two samples were evaluated by GC-MS. In both of the samples monoterpenes were found to be the predominant compounds. Among them α-pinene, linalool, 1,8-cineole, and myrtenyl acetate were the major compounds. Significant differences between the samples were found in the ranges of α-pinene (14.7%–35.9%) and myrtenyl acetate (5.4%–21.6%). Both oils exhibited moderate DPPH scavenging activity, with IC₅₀ values of 6.24 mg/mL and 5.99 mg/mL. The antimutagenic properties were assayed against spontaneous and t-BOOH-induced mutagenesis in Escherichia coli oxyR mutant IC202, a bacterial strain deficient in removing ROS. Reduction of the spontaneous mutagenesis in presence of myrtle EO was only slight, up to 13% at the highest concentration tested. When the oxidative mutagen was used, EO expressed higher reduction of mutagenesis, in a concentration dependent manner, with statistical significance for effect at the highest concentration tested (28%). Suppression of t-BOOH induced mutagenesis was correlated with the observed scavenging activity.

The effects of dietary oregano oil supplementation on pig meat characteristics

The effects of different concentrations of dietary oregano essential oil supplementation on finishing pig meat characteristics were investigated in the present study. Thirty-two barrows and thirty-two gilts were divided into four equal groups. During the experimental period, which started when the animals were 5 months old and finished after 35 days, the first group was fed the control diet (group C), whereas the other three groups consumed the same diet, with the only difference that the feed was supplemented with oregano essential oil at concentrations of 0.25, 0.5 and 1 ml/kg of fed diet (groups OR1, OR2 and OR3, respectively). At the end of the experiment, pigs were fasted for 12 h, weighed and slaughtered. After overnight chilling, a 50 cm loin section was removed from the half of the carcasses (8 pigs per nutritional treatment; 4 barrows and 4 gilts) and transported to laboratory for further examination. No significant differences were observed after dietary oregano essential oil supplementation in final body weight (kg), body weight gain (g) and dressing out (%). Tenderness of longissimus muscle, expressed as shear force value, pH values at 45 min and 24 h postmortem, colour parameters and sensory attributes of eating quality were not significantly influenced by the dietary treatment. Moreover, the lipid oxidation results suggested a lack of antioxidant effect for the oregano essential oil. In conclusion, carcass and meat quality attributes were unchanged, indicating that the dietary administration of different levels of oregano essential oil did not exert any effect on pig meat parameters in the present experiment.

The incorporation of dehydrated rosemary leaves in the rations of turkeys and their impact on the oxidative stability of the produced raw and cooked meat

Thirty-six 12-week-old turkeys were distributed into six groups and were raised for 4 weeks on rations containing 0%, 0.5% or 1.0% dehydrated rosemary leaves as antioxidant in the presence of alpha-tocopheryl acetate from 10 to 300 mg/kg. Following slaughtering, breast and thigh meat samples, raw or cooked, from all six groups were collected to be refrigerated at 4 degrees C for 9 days. All stored samples were submitted to analysis for their concentration in malondialdehyde (MDA), a lipid oxidation marker, and alpha-tocopherol. The results showed that the rations containing 300 mg/kg alpha-tocopheryl acetate increased the mean alpha-tocopherol content of the breast and thigh significantly (P <0.05) compared with the respective control values. No significant (P>0.05) changes could be observed in the alpha-tocopherol content of breast and thigh of turkeys consuming rations containing up to 1% dehydrated rosemary leaves. The refrigeration of the meats led to spontaneous increase in the MDA content of the breast and thigh meat samples. Samples from turkeys fed rations containing 300 mg/kg alpha-tocopheryl acetate showed the lowest mean levels of MDA after the 9-day refrigerated period. The incorporation of rosemary in the rations led to a modest decrease in the formation of MDA in the meats compared with the respective mean control values. The combination of alpha-tocopheryl acetate and rosemary was not associated with an additional decrease in MDA formation.

Antioxidative potential of raw breast meat from broiler chicks fed a dietary medicinal herb extract mix

This study was performed to evaluate the antioxidative potential and quality of the breast meat of broiler chickens fed a dietary medicinal herb extract mix (MHEM, consisting of mulberry leaf, Japanese honeysuckle, and goldthread at a ratio of 48.5:48.5:3.0). A total of 480 one-day-old male Cobb broiler chicks were randomly allotted to 12 pens, with 40 birds per pen (replicate), and reared for 35 d. Dietary treatments consisted of a corn-soybean meal basal diet (control); a basal diet with 0.3% MHEM (T1); and a basal diet with 1% (T2) MHEM. At the end of the feeding trial, breast meat samples were excised and stored in a refrigerator at 4 degrees C to be analyzed at d 0, 3, and 7. The MHEM did not affect proximate composition of the breast meat. Total phenols content of the breast meats in the T1 and T2 diets was approximately 2 times greater than that of the control diet (P < 0.05). 1,1-Diphenyl-2-picrylhy-drazyl radical-scavenging activity and 2,2-azinobis-(3 ethylbenzothiazoline-6-sulfonic acid) cation-reduction activity were greater in the T2 diet at d 0 and in the T1 diet at d 3 compared with the control diet (P < 0.05). 2-Thiobarbituric acid-reactive substance values in the T1 and T2 diets were lower than in the control diet at d 3 and 7 and did not increase during storage, whereas the value in the control diet increased significantly. The pH of the T1 diet was significantly greater than that of the control diet at d 0 and 3. In a sensory test, panelists preferred the T1 breast meat throughout the 7-d storage period. This research indicates that dietary MHEM could increase the antioxidative potential and overall preference of breast meat during cold storage.

The effect of dietary oregano essential oil on microbial growth of rabbit carcasses during refrigerated storage

The effect of dietary supplementation with oregano essential oil on microbial growth of rabbit carcasses during refrigerated storage was investigated. A total of 45 weaned rabbits were separated into three equal groups with three subgroups each. One group was given the basal diet and served as control and the other two groups were administered diets supplemented with oregano essential oil at levels of 100 and 200mg/kg diet, respectively (OR100 and OR200 groups). Total viable counts, Pseudomonas spp., lactic acid bacteria, Brochothrix thermosphacta, Enterobacteriaceae and yeast and mould counts, as well as off-odours and appearance of slime were all assessed on rabbit carcasses stored at 3±1°C for 12 days. The results showed that performance parameters were not affected (p>0.05) whereas the dietary supplementation with oregano essential oil resulted in lower (p<0.05) average microbial counts on the carcasses, compared to controls, throughout storage. Dietary supplementation with oregano essential oil at 200mg/kg was more effective in inhibiting microbial growth compared with 100mg/kg. Sensory evaluation scores indicated that the carcasses obtained from OR100 and OR200 groups gave a noticeable putrid odour after days 8 and 10, respectively, whereas the control carcasses developed off-odours after the 6th day of storage. Slime formation in the controls was observed after day 6, while the OR100 and OR200 groups were just beginning to show slime after days 8 and 10, respectively.