Influence of dietary plant fats and antioxidant supplementations on performance, apparent metabolizable energy and protein digestibility, lipid oxidation and fatty acid composition of meat in broiler chicken

Abstract This study aimed to evaluate the effects of dietary different antioxidants and plant oils on performance, apparent metabolizable energy and protein digestibility, meat quality and meat fatty acid composition of broiler chickens. In all, 480 male broiler chicks of 1‐day old were assigned in a completely randomized design with factorial arrangement 2 × 5 (plant oil sources [soybean and rapeseed oils] and antioxidant sources [vitamin E, Thyme, Rosemary and Satureja essential oils] furthermore control treatment without antioxidant). The results indicated that at 1–42 d of age, growth performance and carcass yield of birds were not influenced by dietary plant oils and antioxidant supplementations. Dietary Thyme essential oil (300 mg/kg) resulted in an increase in crude protein digestibility and birds fed on diets without antioxidant showed increase in the apparent metabolizable energy (p < .01). Birds receiving the combination of soybean oil with Rosemary essential oil had lowest malondialdehyde concentration in comparison to birds receiving other treatments (p < .05) in the drumstick meat. Also, birds receiving the combination of soybean oil with vitamin E had lowest malondialdehyde concentration in comparison to birds receiving other treatments (p < .05) in the breast meat. The results indicated that treatments did not influence water holding capacity of meat. Also, dietary rapeseed oil and Thyme essential oil supplementations, separately, decreased saturated fatty acid (p < .01) and increased unsaturated fatty acid and unsaturated to saturated fatty acids ratio (p < .01) of drumstick meat tissue in broiler chicken (p < .01). In conclusion, dietary rapeseed oil and Thyme essential oil increased in n‐3 polyunsaturated fatty acids in the drumstick meat (p < .01) and a combination of dietary soybean oil, Rosemary essential oil and vitamin E decreased the lipid oxidation in the meat of broiler chickens (p < .05).


| INTRODUC TION
Natural antioxidants have special importance in the maintenance of high growth levels, reproduction and immunocompetence in poultry production. Insufficient intake of antioxidants, a high intake of pro-oxidants or both may lead to oxidative stress (Gao, Lin, Wang, Song, & Jiao, 2010). Dietary polyunsaturated fatty acids (PUFA) are a group of pro-oxidants known to increase oxidative stress in vivo in hens and chickens (Gao et al., 2010). A large proportion of PUFA in dietary plant oils increase the requirement for antioxidants (Cortinas et al., 2005). Additionally, lipid oxidation has negative effects on meat quality of broiler chickens (Brenes et al., 2008). However, an increase in the amount of n-3 PUFAs in foods, especially docosahexaenoic (DHA) and eicosapentaenoic (EPA), may confer greater susceptibility to lipid oxidation, and oxidative deterioration adversely affects the sensory quality of products, including odours or flavours during storage (Gonzalez-Esquerra & Leeson, 2001).
Also, animal feeds contain a range of different compounds that possess antioxidant activities including vitamin E, carotenoids, flavonoids, ascorbic acid and some other compounds (Surai, 2002).
Among the numerous anti-oxidative defence mechanisms, vitamin E is known as a potent antioxidant that prevents free radical damage to tissues. Different authors propose quite different concentrations of vitamin E as being necessary for the prevention of oxidative stress arising from the PUFA content in poultry diets. Leeson and Summers (2008) recommend 3 IU of vitamin E for each gram of added PUFA in 1 kg of feed, whereas German recommendations suggest an almost three times lower supplementation of 0.6 IU/g of PUFA.
Essential oils derived from herbs and spices have also been studied for antioxidant properties in poultry meat. Many studies have also been conducted on the effects of dietary essential oils or combinations on the performance of poultry but with varying and conflicting results. While some reports (Alcicek, Bozkurt, & Cabuk, 2004) demonstrated that essential oils improved animal performance, some researchers indicated that lipid oxidation may be prevented by dietary plant extracts or essential oils in feeds for laying hens (Schiavone, Marzoni, & Romboli, 2001).
Rosemary is aromatic and medicinal plant which has been recognized to have high antioxidant activity (Carvalho, Moura, Rosa, & Meireles, 2005). The substances associated with the antioxidant activity of Rosemary are the phenolic diterpenes, such as carnasol, rosmanol, 7-methyl-epirosmanol, isorosmanol and carnosoic acid, and the phenolic acids, such as rosmarinic and caffeic acids. On the other hand, the major components of Rosemary volatile oil are monoterpenes such as α-pinene, myrecene, 1,8-cineole and borneol.
These compounds possess strong antibacterial activities (Okoh, Sadimenko, & Afolayan, 2010). However, the properties of the volatile oils have been found to vary depending on extraction method used.
Thyme (Thymus vulgaris) is a medicinal herb that can be used as a natural alternative to antibiotics in poultry production but it also has inhibitory effects on abdominal fat traits in broiler chickens (Al- Kassie, 2009). Al- Kassie (2009) showed that adding 200 ppm Thyme oil to the diets of broiler chickens caused a significant reduction in the abdominal fat percentage. Volatile oil from Thyme was assessed for antibacterial and antiviral activity as inhibitors of microbial growth (Dorman & Deans, 2000). The major components of Thyme essential oil are the two predominant components, thymol and carvacrol (Lawrence & Reynolds, 1984).
In the present study, the effect of dietary different antioxidants (vitamin E, Thyme, Rosemary and Satureja essential oils) and plant oils (soybean and rapeseed) on growth performance, carcass characteristics, meat fatty acid composition, crude protein and apparent metabolizable energy digestibility and meat quality in broiler chickens will be investigated.

| Composition of the essential oils
The composition of the essential oils was determined using gas chromatography (GC; Agilent 6890N, Agilent Technologies, Paris, France) interfaced with mass spectroscopy (MS; Agilent 5973N, Agilent Technologies) ( Table 1). The capillary column used was the HP5-MS 5% phenyl methyl siloxan (length: 30 m; internal diameter: 0.25 mm; film thickness: 0.25 µm) and an automatic passer (Agilent 7683B; Agilent Technologies). Helium was the carrier gas at a flow rate of 1 ml/min. The column temperature was initially adjusted at 5°C (during 1 min) then increased progressively at a rate of 2°C/min to reach 300°C within 130 min. The samples were diluted in ethanol (1/10) then 1 µl was injected into GC-MS (Bampidis et al., 2005).
The components were identified by comparing their relative retention times and mass spectra with the standard data (NIST 05, Mass Spectra Library, National Institute of Standards and Technology, Gaithersburg, MD). The GCMS analyses were conducted at Institut National de la Rechercheetd'Analyses Physico-chimiques (Sidi-Thabet, Tunisia).

| Animal and experimental procedures
A total number of 480 male broiler chicks of 1-day old (Ross 308) obtained from the Mahan Breeder Company (Varamin, Tehran), were weighed and randomly assigned to 10 treatments and each group divided to four replicates with 12 male birds each in a completely randomized design with factorial arrangement 2 × 5 (plant oil sources [soybean and rapeseed oils at level of 4% of diet] and antioxidant sources [200 mg/kg vitamin E, 300 mg/kg rosemary, Thyme and Satureja essential oils] plus a control group that did not receive antioxidant). The basal diet was formulated to meet the nutrient requirements of the broiler chickens as recommended by Ross 308 broiler management guide (AVIAGEN, 2002) ( Table 2). The experimental diets were based on corn-soybean meal containing vegetable oil.
Feed and water were provided ad libitum. Temperature and relative humidity were maintained within the optimum range. The birds were kept in 40 Cage (1 × 1.1 m) and photoperiod of 24 hr light/day was maintained during on days 1-3 of age and 23 hr light/1 hr of darkness on day 42. The ventilation rate was 0.12 m/s during the whole period. The initial house temperature was 32°C and then gradually decreased to reach 20°C at 42 days of age. All animal procedures were approved by the Animal Care Committee of the Animal Sciences Research Institute of Iran. All chicks were fed starter diets (1-10 days of age), grower diets (11-24 days of age) and finisher diets (25-42 days of age). All diets were prepared freshly every week and diets were in mash form.

| Performance and carcass characteristics
Feed intake and body weight were recorded during the starter period (1-10 days), grower period (11-24 days), finisher period (25-42 days) and the total experimental period (1-42 days) and then the weight gain, feed intake and feed conversion ratio (FCR) (feed/gain) were calculated.
At the 42nd day of age, two birds per pen were slaughtered and carcass, drumstick, breast, abdominal fat pad and pancreas were weighed and calculated as a percentage of live body weight.

| Apparent metabolizable energy and digestibility of protein
Digestibility of nutrients was measured using Cr 2 O 3 (0.3% of the grower diet) as indicator described by Petry and Rapp (1971). The digestibility study included 3-d pre-experimental adaptation period (20-22 days of age) followed by 3-d collection period (23-25 days of age). During each 3-d collection period, pooled excreta samples from respective treatment cages (n = 3/treatment) were collected daily. After contaminants, such as feathers and other foreign materials, were carefully removed, the excreta samples (n = 9/treatment) were stored in air-tight containers at -20°C until later analysis. Feed and excreta samples were dried at 60°C for 48 hr, ground to pass through a 0.5-mm sieve, and stored in air-tight containers at −20°C. Gross energy was determined using an adiabatic oxygen bomb calorimeter (Parr Instrument Company, Moline, IL). All samples were analysed in duplicates. Chromic oxide concentrations in the feed and excreta were determined using the procedure described by Fenton and Fenton (1979). The digestibility coefficients (DC) of protein and AME were calculated using the following equation: where Cr 2 O 3diet is the concentration of chromium in the diet (%), Cr 2 O 3excreta is the concentration of chromium in the excreta (%), nutrient faecal is the concentration of the nutrient (also for GE) in the excreta (%), nutrient diet is the concentration of the nutrient (also for TA B L E 1 Composition of essential oils of Rosemary, Thyme and Satureja GE) in the diet (%), GE diet is the GE content of the diet (kcal/kg) and GE excreta is the GE content of the excreta (kcal/kg).

| Lipid oxidation
Malondialdehyde (MDA), the compound used as an index of lipid peroxidation, was determined by a selective third-order derivative spectrophotometric method on the 3, 6 and 9 days of storage (Botsoglou, Florou-Paneri, Christaki, Fletouris, & Spais, 2002 TA B L E 2 Composition of the experimental basal diet 70°C for 30 min. Following incubation, the mixture was cooled under tap water and submitted for conventional spectrophotometry (Shimadzu, Model UV-160A, Tokyo, Japan) in the range of 400-650 nm. Third-order derivative spectra were produced by digital differentiation of the normal spectra using a derivative wavelength difference setting of 21 nm. The concentration of MDA in analysed samples was calculated on the basis of the height of the third-order derivative peak at 521.5 nm by referring to slope and intercept data of the computed least-squares fit of standard calibration curve prepared using 1,1,3,3-tetraethoxypropane (Sigma Chemical Co, St. Louis, MO).

| Water holding capacity
Water holding capacity (WHC) was determined by centrifuging, according to Bertram, Andersen, and Karlsson (2001) on samples collected 4 hr after slaughter (one sample from breast and drumstick meats per chicken). Samples weighing about 1 g were centrifuged at 4,000 x g for 15 min. The expressed juice was defined as the loss in weight after centrifugation at 4,000 x g at 15 min. The expressed juice was defined as the loss in weight after centrifuged and presented as a percentage of the initial weight of the original sample. Total moisture content was determined in duplicate according to AOAC 1 procedures (AOAC, 2005). The WHC was calculated as the fraction of water retained by the meat (1-(expressible juice/total moisture content)).

| Fatty acid composition analysis
Drumstick meat were analysed for their fatty acid composition following the methods of lipid extraction adapted from the procedure of Folch, Lees, and Stanley (1957) and saponification/methylation adapted from the procedure of Metcalfe, Schmitz, and Pelka (1966).
Approximately 0.5 g of drumstick meat was homogenized completely in a 10-ml mixture of chloroform and methanol (2:1). After filtration of samples through Whatman #4 filter paper (>20 to 25 μm), 2 ml of 0.88% KCl solution was added to the extract. The extract mixtures were then centrifuged at 2,000 x g for 30 min at room temperature.
The upper phase of the extract was discarded, and the lower phase was transferred into a reaction vial and dried under nitrogen. After adding 0.5 Ml of 0.5 N NaOH in methanol to the dry samples, samples were heated for 5 min at 100°C in a heating block. Samples were cooled to room temperature; 0.5 ml of boron trifluoride in methanol was then added to the sample, after which the samples were heated an additional 5 min at 100°C and cooled to room temperature. One millilitre of hexane and 1 ml of saturated NaCl were added to samples, and samples were centrifuged at 1,500 x g for 5 min.

| Statistical Analyses
The data were subjected to two-way analysis of variance with plant oil and antioxidant sources as the main effects as a completely randomized design with factorial arrangement 2 × 5 using the general linear models (GLM) procedure of SAS software (SAS, 2003).
Significant differences among the means were determined using Tukey's multiple-range test at p < .05.

| Chemical composition of the essential oils
The results obtained by GC and GC-MS analysis of the SATUREJA, Thyme and Rosemary essential oils are presented in

| Effect of dietary different antioxidants and plant oils on growth performance and carcass yield
Growth performance (feed intake, weight gain and feed conversion ratio) during the starting, growing, finishing and total periods (Table 3) and carcass yield (Table 4) were not influenced by dietary plant oils (soybean and rapeseed) and different antioxidants (Thyme, Rosemary and Satureja essential oils and vitamin E). According to the above study, the interaction of plant oils by antioxidant sources did not affect the growth performance and carcass yield in broiler chicken.

| EFFECT of dietary different antioxidants and plant oils on apparent metabolizable energy and digestibility of protein
As shown in

| Effect of dietary different antioxidants and plant oils on lipid oxidation of meats
The effect of different plant oils and antioxidants on lipid oxidation drumstick and breast meats is shown in Table 6. Furthermore, the effect of different times and treatments on lipid oxidation drumstick and breast meats are shown in Table 7. Thiobarbituric acid (TBA) analysis is an efficient way to measure antioxidant activity in meat products. This analysis is an indicator of malondialdehyde (MDA), a product of oxidation; thus, the TBA value increases during the storage period. MDA is an important index for lipid peroxidation and oxidative damage caused by reactive oxygen species.
At the end of this experiment, malondialdehyde (MDA) concentration in drumstick muscle of combination of rapeseed oil and vitamin E supplemented treatment was significantly higher than the other treatments after 3 days of storage (p < .05). Also, lower MDA TA B L E 3 Effects of different antioxidants and plant oils on growth performance of broilers between 1 and 42 days of age

| Effect of dietary different antioxidants and plant oils on water holding capacity
The effect of different antioxidants and plant oils on water holding capacity is shown in Table 6. Diets with different antioxidants (rosemary, Thyme and Satureja essential oils and vitamin E) and plant oils (soybean and rapeseed) had no marked effect on water holding capacity in drumstick and breast meat. Also, the interaction of plant oils and essential oils had no significant effect (p ˃ .05) on water holding capacity.

| Effect of dietary different antioxidants and plant oils on fatty acids composition
The results of fatty acid composition of the drumstick meat are presented in Table 8. Results showed that the addition of rapeseed oil to the diets modified the fatty acid composition of drumstick muscle by reducing (p < .01) saturated fatty acid and increasing (p < .01) unsaturated fatty acid in drumstick meat. Also, use of the rapeseed oil to the diets caused significant increase in unsaturated to saturated fatty acids ratio in the drumstick meat (p < .01).
Also, use of the Thyme essential oil to the diets caused significant increase in unsaturated fatty acid and unsaturated to saturated fatty acids ratio and decrease saturated fatty acids compared with Satureja essential oil in the drumstick meat (p < .05). Diets with vitamin E, SATUREJA and Rosemary essential oils and without antioxidant treatments had no marked effect on unsaturated fatty acid, unsaturated to saturated fatty acids ratio and saturated fatty acids. Mathlouthi et al. (2012) determined that the there was no differences in weight gain from 1 to 42 d of age when broiler chickens were fed Rosemary essential oil than the other treatments.

| Effect of dietary different antioxidants and plant oils on growth performance
Basmacioglu, Tokusoglu, and Ergul (2004)   of fatty acids (Leeson & Summers, 2008). Moreover, Leeson and Summers (2008) reported that the optimum ratio of unsaturated to saturated fatty acids for maximizing fat digestibility and the metabolizable energy value of fat is around 3 to 1.
Therefore, absence of positive effect of antioxidants in some experiments may be due to using a smaller dose which was insufficient to produce its effect on poultry. Also, the conflicting results of the effects of plant oils on performance traits could be due to differ-

| Effect of dietary different antioxidants and plant oils on carcass characteristics
These findings are in agreement with the results of Ocak et al.  attributable to the saponins in essential oils, which have inhibitory effects on lipogenesis, but in our experiment, these effects were not observed. Absence of positive effect of antioxidants in some experiments may be due to using a smaller dose which was insufficient to produce its effect on poultry.

| Effect of dietary different antioxidants and plant oils on apparent metabolizable energy and digestibility of protein
Herbs and spices have traditionally been used to stimulate the production of endogenous secretions in the small intestinal mucosa, pancreas and liver, and thus aid digestion. Mansoub (2010) reported that the carvacrol in herbs and essential oils has stimulatory influence on pancreatic secretions by increasing the secretions of digestive enzymes, which more amounts of nutrients like amino acids can be digested and absorbed from the intestine and thereby improve some of the carcass characteristics. Herbs and phytogenic products could control and limit the growth and colonization of numerous pathogenic and non-pathogenic species of bacteria in chicks guts. This may lead to a greater efficiency in the utilization of food, resulting in enhanced growth and improved feed efficiency. Also, there are studies that dietary essential oils addition could improve the digestion process. Lee et al. (2003) reported that cinnamaldehyde in diet had a role in the digestion process. In another study in which thymol was used, pancreatic total and activities of trypsin and total lipase activity were significantly greater in 50 mg of thymol than those in the control diet. It has been reported that feeding essential oil, extracted from herbs, improved the secretion of pancreatic digestive enzymes in broiler chickens. A mixture of carvacrol, cinnamaldehyde and capsaicin used as feed additive for broilers is shown to enhance activities of pancreatic trypsin and α-amylase in tissue, as well as in the jejuna chyme content (Jang, Ko, Kang, & Lee, 2007).  monoglycerides and long-chain unsaturated fatty acids to conjugated bile salts promptly forms micelles. Micelles play key roles in solubilizing fatty acids with low polarity and fat-soluble vitamins and leading to their absorption across the intestinal epithelium (Leeson & Summers, 2008).

| Effect of dietary different antioxidants and plant oils on lipid oxidation of meats
Because of high proportion of PUFA, poultry meat is more susceptible to oxidative processes, specifically lipid oxidation, than beef or pork. Unfortunately, plant oils rich in PUFA are highly susceptible to oxidative deterioration. The products of lipid oxidation can decrease the nutrient content of the feed by reacting with proteins, lipids and fat-soluble vitamins, which may even form toxic products that can adversely affect broiler performance and health (Smet et al., 2008).
Therefore, incorporation of dietary antioxidants, such as vitamin E and essential oils in poultry feed, has been implemented to achieve optimal growth performance, reproduction and meat quality.
Yesilbag, Eren, Agel, Kovanlikaya, and Balci (2011)  separately, and the meat samples were exposed to higher oxidation when the storage time was extended; the breast meat was found to be more durable than the thigh meat after 15 d of storage. They also reported that rosemary, Thyme oil and α-tocopherol acetate prevented meat from oxidation equally effectively during the early storage period, but Rosemary and Thyme oil were better at preventing the meat from oxidation than α-tocopherol acetate over a longer storage period. The plants and their essential oils are rich in phenol compounds like polyphenols that might inhibit free radical formation. Thus, the inhibition of lipid oxidation might be related to the phenolic compounds in essential oils. Sahin, Sahin, and Yaralioglu (2001) reported that vitamin E inhibit production of free radicals by blocking lipid peroxidation. Morrissey, Brandon, Buckley, Sheehy, and Frigg (1997) reported that dietary supplementation of chicken diets with α-tocopherol increased concentration while markedly decreasing MDA concentration. Vitamin E is well accepted as the first line of defence against lipid peroxidation.
By its free radical quenching activity, vitamin E breaks chain propagation and thus terminates free radical attack at an early stage. Dransfield and Sosnicki (1999) reported that water holding capacity is related to pH value, and observed that the lower final pH resulted in a decrease in water holding capacity. In postmortem muscle, the substrates glycogen, glucose and glucose-6-phosphate are converted to lactate through anaerobic glycolysis. Lactate accumulation and the release of protons from adenosine triphosphate hydrolysis in postmortem muscle induce a pH decline. A rapid pH decline may induce protein denaturation, resulting in decreased juiciness and less intense (or pale) muscle coloration. Poultry meat with low pH has been associated with low water holding capacity, which results in increased cook-loss and drip loss (Qiao, Fletcher, Smith, & Northcutt, 2001). This finding is consistent with the observations of Mahmoodi Bardzardi, Ghazanfari, Salehi, and Sharifi (2014), who reported that essential oils of diets had no effect on water holding capacity.

| Effect of dietary different antioxidants and plant oils on fatty acids composition
The lipids in poultry exhibit a higher degree of unsaturation compared with red meat because of a relatively high content of phospholipids. The degree of unsaturation of phospholipids in subcellular membranes is an important factor in the determination of oxidative stability of meats (Coetzee & Hoffman, 2001). In relation to the character of the auto-oxidation process, the effect of antioxidants is more significant the sooner they are applied. The ideal situation is when fats are protected immediately after the slaughter of animals.
Such protection can be achieved by feeding animals with feed containing antioxidants (Coetzee & Hoffman, 2001). Feeding of poultry with a higher level of natural dietary antioxidants provides the poultry industry with a simple method for improvement of the oxidative stability, sensory quality, shelf life and acceptability of poultry meats.
Vitamin E and essential oils belong to substances with significant anti-oxidative activity.
The fatty acid profile of meat could be altered by adding plant oils to the feed for broilers (Zelenka, Jarosova, & Schneiderova, 2008).
Generally, the concentrations of n-3 PUFA increased, whereas n-6 PUFA tended to decrease in meat lipids in response to dietary n-3 PUFA. The PUFA are the most sensitive fractions to oxidation processes and lipid oxidation in meat are one of the reasons for quality degradation during storage. Enhancement of unsaturated fatty acids in drumstick lipids would result from diminution of fatty acid oxidation in drumstick, especially at the birds to the received rapeseed oil.
This antioxidant activity of vitamin E was supported in the present study; the linolenic fatty acid concentration in drumstick meat was significantly greater than to other treatments. It was thought that the antioxidant activity of vitamin E blocked lipid peroxidation of drumstick lipids, especially linolenic fatty acid. For this reason, linolenic fatty acid in the drumstick in birds fed diets supplemented with vitamin E increased compared to other groups birds and also, linolenic fatty acid in the drumstick in birds fed diets with rapeseed oil and without antioxidants, had significant decrease (p < .05) compared to other treatments. Botsoglou et al. (2002) determined that α-tocopherol acetate and Thyme oil have nearly similar antioxidant activities, while αtocopherol acetate was sometimes found to be more efficient.
Vitamin E is well accepted as the first line of defence against lipid peroxidation. By its free radical quenching activity, vitamin E breaks chain propagation and thus terminates free radical attack at an early stage (McDowell, 1989). Also, medicinal plants and essential oils may have the potential to improve the fatty acids due to the plant phenolic compounds (e.g. polyphenols) and organic acids because they exerted the antioxidant potential and that might inhibit free radical formation and consequently prevent the oxidation of PUFA (Jang et al., 2008). The anti-hyperlipidaemic activity due to the phenolic acids of medicinal plants might be attributed in the improvement of the fatty acid content of broiler meat through the lipid homeostasis and fatty acid synthase enzyme (Lin, Hsu, & Yin, 2013). Bolukbasi, Erhan, and Ozkan (2006) reported that the addition of Thyme oil to the broiler feed led to a significant reduction in the saturated (SFA) and polyunsaturated fatty acid (PUFA) concentrations of the leg and breast tissues. Consistent to that, several researchers have suggested that it would be possible to modify the fatty acid contents in poultry meat through dietary manipulation of natural plant materials (Ahmed et al., 2015;Sarker, Kim, & Yang, 2009). This finding suggests that fatty acid profile of meat could be altered by adding plant oils to the feed for broilers and antioxidants can extend the shelf life and improve the quality of meat products.

| CON CLUS ION
Results of the present study indicated that feeding broiler chickens with rapeseed oil resulted in increasing unsaturated fatty acids and decreasing saturated fatty acids as compared to soybean oil in the drumstick meat. Furthermore, the feeding broiler chickens with Thyme essential oil resulted in increasing unsaturated to saturated fatty acids ratio as compared to other treatments in the drumstick meat. Therefore, dietary rapeseed oil and Thyme essential oil resulted to increasing in n-3 polyunsaturated fatty acids in the drumstick meat. Also, Thyme essential oil was increased crude protein digestibility. Furthermore, the lipid oxidation was reduced by the combination of dietary soybean oil and Rosemary essential oil and vitamin E in meats of broiler chicken.