Since long time, antibiotics (growth promoters) in animal feeds under intensive farming had positive impact on feed conversion efficiency. The use of antibiotics in broilers feeds has been limited in the European Union and many other regions of the world. A manipulation of gut function and microbial habitat of domestic animal with feed additives has been recognized as an important tool for improving growth performance and feed efficiency [1] . Approximately 80% of domestic animals have been fed synthetic compounds for the purpose of either medication or growth promotion [2] . The banning of the use of antibiotics as feed additives has accelerated and led to find nontraditional feed additives to be used in animal feeds. Herbal extracts are being used as feed additives to improve animal performance especially under the intensive management systems [3] . Both health status and general performance can be supported by plant extracts [4] - [9] . The positive impact on animals health and performance could be achieved through the stimulation of appetite and feed intake, the improvement of endogenous digestive enzyme secretion, activation of immune response and, antiviral, antioxidant and antihelminthic actions. It was found that Fenugreek seeds are rich in protein, fat, total carbohydrates and minerals such as calcium, phosphorus, iron, zinc and magnesium [10] . Moreover Fenugreek benefits the digestive system [11] .

Chamomile flowers inhibit the excessive growth of intestinal harmful microorganism, thus counteracting inflammation, [12] . Nettle (Urtica dioica) has been used to promote health. Numerous analyses of nettle have revealed the presence of more than fifty different chemical constituents. It has been extensively studied and found to contain starch, gum, albumen, sugar, and two resins. Histamine, acetylcholine, choline, and serotonin are also present. Thyme (Thymus vulgaris ) with the main components of Phenols, thymol (40%) and carvacrol (15%) [13] . This herb is also used traditionally for medicinal purposes [13] .

Mentha species―of the family labiatae―are being valued especially for its antiseptic properties and its beneficial effects on the digestion [14] .

The pharmacological action of active plant substances or herbal extracts in humans is well known, but in animal nutrition the number of precise experiments is relatively low. The objective of this research was to investigate effects of a blended natural herb extract when supplemented to regular broiler and an antibiotic free broiler feed.

The data which obtained from performance of broiler chickens fed by herbs and their combination are shown in Table 2. There were a significant effect on food intake of treated chicks (P < 0.05). The highest amount of food intake were in birds consuming the chicken plus compared to the control birds consuming the regular broiler diets. At age of 33 d birds supplemented with the herb extract ate 10 and 12% more feed compared to the control birds. However, birds supplemented with the extract gained more (P < 0.05) weight compared to birds consuming the regular broiler diet. At time of termination of the feeding trial (day 33) birds supplemented with the herb extract had 18 and 22% increase in the average weights. Similar trend was observed in the FCR where it was higher (P < 0.05) in birds supplemented with the herb extract.

Carcass and visceral organ variables were expressed as percentages of live weights. Table 3 shows the effect of extract on carcass and its parameters. According to the data, there were no significant differences in the carcass characters. However, there was a numerical differences among the tested parameters. The lowest percen-

¹C = control basal diet, CC plus = control basal diets supplemented with chicken plus (300 ml/m³), AFC plus = antibiotic free diet supplemented with chicken plus (300 ml/m³). ²Means in the same raw with different superscripts are significantly different (P < 0.05) using Tukey’s HSD test.

¹C = control basal diet, CC plus = control basal diets supplemented with chicken plus (300 ml/m³), AFC plus = antibiotic free diet supplemented with chicken plus (300 ml/m³).

tage of gizzard, bursa and spleen were in birds supplemented with the herb extract, especially when associated with feeds lacking growth promoters. Bursa relative weight was numerically the lowest in the control birds compared to the other two treatments (0.10, 0.12, 0.16). Similar trend was observed for spleen where relative weights were 0.07, 0.11 and 0.11 for the control, birds fed regular or growth promoter deficient feeds, respectively.

Carcass cuts relative weights were not affected by type of treatment (Table 4). Feeds supplemented by the herb extract resulted in higher dressing proportions compared to control birds. The dressing proportions were 70.5%, 77.0% and 75% for the control, birds fed regular or growth promoter deficient feeds, respectively.

Mortality percent was around 3% and cases of sudden death were minimal (only 2 cases).

The results of economical efficiency (EF) and relative economical efficiency (REF) estimated for the experimental diets used during the experiment are shown in Table 5. According to the input?output analysis, the best R.E.E were recorded by the birds fed CC plus followed by birds fed AFC plus compared to the control birds.

The initial live body weight of chicks at one-day old showed similar values with no significant differences among treatment groups. There were a significant effect on food intake of treated chicks. The highest amount of food intake were in birds consuming the C plus and AFC plus diets compared to the control birds consuming the

¹C = control basal diet, CC plus = control basal diets supplemented with chicken plus (300 ml/m³), AFC plus = antibiotic free diet supplemented with chicken plus (300 ml/m³). ²Means in the same raw with different superscripts are significantly different (P < 0.05) using Tukey’s HSD test.

¹C = control basal diet, CC plus = control basal diets supplemented with chicken plus (300 ml/m³), AFC plus = antibiotic free diet supplemented with chicken plus (300 ml/m³). ²Means in the same raw with different superscripts are significantly different (P < 0.05) using Tukey’s HSD test.

regular broiler diets (C). The positive effects of herbs on body weight and general performance may be due to the presence of a mixture of essential fatty acids including linolenic and linoleic acids presented in some herbs, especially the black seeds which are essential for growth [17] . Toghyani et al. [18] reported that the low dosage (5 g/Kg) of Thyme have significant effect on broiler body weight and their feed conversion ratio. Najafi et al. [19] reported that the group which fed by thyme-included diet had significantly better body weight and feed conversion ratio, But Tekeli et al. [20] and Demir et al. [21] reported opposite results; they found that thyme has no influence on broilers performance.

Our findings showed that there was 8 to 11% improvement in FCR of birds supplemented with the herb extract. The improvement in protein utilization, absorption and suppression of gram negative bacteria and Cholostridium that cause growth depression might be the reason for the improvement in body weight and feed conversion ratios [22] [23] . El-Gendy et al. [24] reported that the improvement in feed conversion ratio with feeding herbal extract could be associated with improving the digestibility of dietary protein in the small intestine. The action of herbal extracts as antioxidants, anti bacterial, anti fungal and anti protozoa also add to the positive improvement in birds performance [25] .

Several metabolites play the role in the physiological, chemical function of digestive tract and the microbial population in animals gut among these are the isoprene derivatives, flavonoids, glucosinolates and other plant metabolites may affect the physiological and chemical function of the digestive tract [5] [26] [27] .

Our findings are in agreement with what was reported by [28] . Elbushra et al. [28] reported that live body weight at 6 weeks old, body weight gain, feed conversion ratio and protein efficiency ratio were significantly improved for chicks fed diets supplemented with fenugreek at rate of 0.5% or 1.5% as compared to control diet. Supplementation of fenugreek had significant effect for broiler chicks in live body weight, body weight gain, feed conversion ratio, protein efficiency ratio, feed consumption and efficiency of energy utilization [28] . Similarly, supplementation of chamomile flowers at level of 2.5 kg/ton of broiler diet improved growth performance and feed conversion [29] . Chamomile (Matricaria Chamomilla L.) contains chemicals as flavones opigenin, essential oil such as bisaboloxide B, α-bisabolol, chamazulene and bisababoloxide A [30] .

According to our data, there were no significant differences in the carcass characters and visceral organ relative weights. However, there was a numerical differences among the tested parameters. However, the debate on the real effects of nettle on broilers performance can be explained by the nettle variety or chickens used, farm management and operations used in the rearing of broiler chickens. The carvacrol in nettle has stimulatory effects on pancreatic secretions [31] by increasing the secretions of digestive enzymes more amounts of nutrients like amino acids can be digested and absorbed from the digestive tract and thereby improve carcass traits.

The results of economical efficiency (EF) and relative economical efficiency (REF) estimated for the experimental diets used during the experiment are shown in Table 5. According to the input-output analysis, the best R.E.E were recorded by the birds fed CC plus followed by birds fed AFC plus compared to the control birds.

These results indicated that the diets containing herbal extract were more economical than the control diet. This improvement could be due to improving the feed conversion or reducing the amount of feed required to produce one unit of meat. These findings are in agreement with previous research where herbal extracts improved the economic evaluation [29] [32] - [34] .

The recorded mortalities were 3% in average compared to that in commercial operations which is 5% - 7%. This reduction in broilers’ mortalities could be explained by improvement in birds general performance and better build up of the immunity caused by the supplement.

The herb extract had several advantages when supplemented to broilers. Significant improvement in body weights, FCR and dressing percentages. The relative economic efficiency was up to 10% improved by the herb supplement. Our results were comparable to Cobb 500 standards and more.

The authors wish to thank Mr. Afif Tanous for his valuable support. Appreciation is extended to Dr. Nasouh Badran; Dr. Mohamad Badran and Mr. Ahmad Abu Al Rub for their endless assistance in many aspects of this project. The authors also thank the Bajjora Company and its staff.

J. AboOmar,A.Hejazi,R.Badran, (2016) Performance of Broilers Supplemented with Natural Herb Extract. Open Journal of Animal Sciences,06,68-74. doi: 10.4236/ojas.2016.61009