Abstract: This experiment was conducted to evaluation the effects of Prebiotic, Garlic powder and Turmeric powder on performance and carcass characteristics of broiler chickens. Based a randomized completely design, 240 days old Ross 308 broilers were distributed into 16 floor pens and reared for 42 days. A basal diet was formulated according to NRC recommendations for starter (0-21 days) and grower (22-42 days) periods. The basal diet was also supplemented with prebiotic Biolex-MB, garlic powder and turmeric powder, resulting 4 dietary treatments were prepared including control group. Each dietary treatment was fed ad-libitum to 4 replicates group of 15 birds at the bigining of rearing period. The result of present study indicated that the diets containing feed additives had no significant effect on broilers performance with an except of Biolex-MB, which improved weight gain and feed conversion ratio (p<0.05). Supplementation of biolex-MB in diet significantly (p<0.05) affected the amount of carcass, thigh and breast (p<0.05). The highest percent of carcass and thigh were found in biolex-MB and control bird groups, respectively (p<0.05). The percent of breast was not affected whit feed treatments.

INTRODUCTION

Recently, the use of antibiotic growth promoter in poultry industry has been seriously criticized by governmental policy makers and consumers because of the development of microbial resistance to these products and the potential harmful effects on human health (Botsoglu and Fletouris, 2001; Williams and Losa, 2001; McCartney, 2002). At present and up till 2009, only 4 antibiotic growth promoter are permitted for use in poultry nutrition. On the other hand, there is increasing public and government pressure in several countries of EU and some non-EU to search for natural alternative to antibiotics (Williams and Losa, 2001; McCartney, 2002). Probiotic, prebiotic and medicinal plants as natural feed additives are recently used in poultry diet to enhance the performance and the immune response of birds. Prebiotics are indigestible carbohydrates that leave a desired effect on the host, by selective growth stimulation or activation of one or more bacteria in a large part of the GI tract (Gibson and Roberfroid, 1995). Biolex-MB is a commercial prebiotic of the Mannan-oligosaccharides family, which is obtained by extraction from the outer cell wall of the yeast Saccharomyces cerviciae. Garlic (Allium sativum) is well known as a spice and herbal medicine for the prevention and treatment of a variety of diseases (Adibmoradi et al., 2006). The major active ingredients of garlic are allicin, ajoene, S-allyl cysteine. Garlic has been found to demonstrate antimicrobial activity (Adibmoradi et al., 2006), lower serum and liver cholesterol (Qureshi et al., 1983) and improve productive performance of broiler chicks (Demir et al., 2003). Curcuma longa (turmeric) is a perennial herb that grows to a height of 3-5 feet and is cultivated extensively in Asia (India and China) and other countries with a tropical climate. Curcumin, the active ingredient from the spice turmeric is a potent antioxidant and anti-inflammatory agent with hepatoprotective, anticarcinogenic and antimicrobial properties (Pal et al., 2001).

The purpose of this study was to investigate, the effect of prebiotic, garlic powder and turmeric powder supplementation in diets on broilers performance.

MATERIALS AND METHODS

Bird and diet: In this study, 240 broiler chickens of the commercial Ross 308 strain were used in a randomized completely design with 4 treatment and 4 replicates in each treatment and 15 birds/replicates and reared on the floor pens for 42 days.

Table 1:	Ingredient compositoin (as percent of dry matter) and calculated analysis of the basal diets
Vitamin and mineral provided/kg of diet: vitamin A, 360000 IU; vitamin D3, 800000 IU; vitamin E, 7200 IU; vitamin K3, 800 mg; vitamin B1, 720 mg; vitamin B9, 400 mg; vitamin H2, 40 mg; vitamin B2, 2640 mg, vitamin B3, 4000 mg; vitamin B5, 12000 mg; vitamin B6, 1200 mg; vitamin B12, 6 mg; Choline chloraid, 200000 mg, Manganeze, 40000 mg, Iron, 20000 mg; Zinc, 40000 mg, coper, 4000mg; Iodine, 400 mg; Selenium, 80 mg

A basal deit was formulated as control according to NRC (1994) recommendations for starter (0-21 days) and grower (22-42 days) periods. The required amount of growth stimulating additives under study was added to the basal diet so that in addition to the control treatment, four dietary experimental treatments containing prebiotic Biolex-MB (2000 g ton^-1), Garlic powder (1000 g ton^-1) and Turmeric powder (1000 g ton^-1) were prepared (Table 1). During the experiment, water and feed were given to the birds ad-libitum.

Sample collection: Weighing of the feed and chickens were made on a weekly basis. At the end of the experiment, 2 birds from each replicate of treatments were slaughtered for separation of carcasses (Perreault and Leeson, 1992).

Statistical analysis: All data were analyzed using the one-way ANOVA procedure of SAS^® (SAS, 1998) for analysis of variance. Significant differences among treatments were identified at 5% level by Duncan (1955) multiple range tests.

RESULTS AND DISCUSSION

Growth performance: The effect of experimental treatments on the performance of broiler chickens is given in Table 2. Weight gain and feed conversion ratio were only affected by dietary Biolex-MB in 0-21, 22-42 and 0-42 days of experiment (p<0.05). There were no significant difference in feed intake across treatments. Mohan et al. (1996), Piray et al. (2007), Pelicano et al. (2004) and Thitaram et al. (2005) have observed the beneficial effects of prebiotics on the body weight gain of broiler chickens. Pelicano et al. (2004); Maiorka et al. (2001) and Santin et al. (2001) reported that in birds under prebiotic nutrition, the FCR was improved significantly as compared with the control treatment. In contrast with our study, Ignacio (1995) and Kumprecht and Zobac (1997) reported that the use of prebiotics in the ration of broiler chickens reduce the feed conversion ratio. The use of prebiotics, by increasing in length of the intestinal mucosa, increases the absorption areas and improves the birds growth performance (Santin et al., 2001). The data of present study show that dietary garlic and turmeric meal can not affect the growth performance of broiler chickens.

Our results was consistent whit Horton et al. (1991), Dey and Samanta (1993), Namagirilakshmi (2005) and Mehala and Moorthy (2008), who reported that supplementation of garlic powder and turmeric powder in diet had no significant effect on weight gain and feed conversion ratio. In the other hand, Shi et al. (1999) and Kumar et al. (2005) observed a positive effect of garlic powder and turmeric powder on broiler performance, respectively. Variance between reports of researchers could be related to differences in management and environmental conditions that be exist in various experiments. It's suggested that under benefit management and/or environmental conditions, the effect of such feed additives may be worthless.

Carcass composition: The effect of experimental treatments on the composition of the bird carcasses (in grams) and the carcass efficiency (in %) are given in Table 3. The weight of the dressing carcass, thigh and breast in birds under Biolex-MB treatment was significantly higher as compared with other treatments (p<0.05). The birds under Biolex-MB and garlic powder treatments had the higher carcass percent than other groups. Also, birds under control treatment had the highest thigh percent as compared with Biolex-MB and garlic powder treatments (p<0.05). The positive effect of the prebiotic use on the weight of broiler carcasses (Yusrizal and Chen, 2003; Ammerman et al., 1989; Piray et al., 2007) confirm the results of this experiment. No significant differences were detected in other carcass composition (as gram or percent) of birds fed garlic powder and turmeric powder when compared to control group. Durrani et al. (2006) observed no improvement in amount of breast and thigh by application of turmeric. However, our findings on carcass composition were in contrast to those of Pelicano et al. (2003); Waldroup et al. (1993); Takahashi et al. (2005) and Javandel et al. (2008).

Table 2:	The main effects of treatments on performance of broiler chickens (mean±SE)
a,bMeans in each column with different superscripts are significantly different (p<0.05)

Table 3:	The effect of feed additives on carcass composition of broiler chickens
a,b,cMeans in each row with different superscripts are significantly different (p<0.05)

CONCLUSION

In generally, the results of the present experiment show that prebiotic Biolex-MB can be used as an effective feed additive to improve broilers performance.