Antibiotic – based growth promoters have been commonly used as supplements in animal feeds for many years because they are well known to help growing animals to digest their food more efficiently and to grow strong and healthy individuals (Sojoudi et al., 2012). Some of the common antibiotics used in animal feeds are virginiamycin, salinomycin, neomycin, doxyclin and avilamycin (kumar et al., 2010). The use of antibiotic – based growth promoters has faced serious criticism and global concern due to their purported hazardous effects including microbial resistance and their potentially harmful effects on human health (Rahmatnejad et al., 2009). These shortcomings lead to the search for alternative substances that eliminate these threats (Manesh, 2012). Nowadays there is increasing interest in the use of natural growth promoters such as probiotics, prebiotics or their combination and medicinal plants as feed additives in poultry diets to enhance the performance of poultry birds (Khan et al., 2012, 2011a).
Garlic (Allium Sativum) has been known in folk medicine for thousands of years in the history of Greeks and Egyptians (Horton et al., 1991). Garlic is best known as a spice and herbal medicine for the treatment and prevention of an array of diseases (Adibmoradi et al., 2006).
Garlic contains at least 33 sulphur containing compounds, several enzymes and 17 amino acids and minerals including selenium (Newall et al.,1996). The major active ingredients in garlic active ingredients in garlic are allicin, ajoene, diakyl polysulphides, s– allylcysteine, diallylsulphide, s – methyl – cysteine sulphoxide and s– allylcysteine sulphoxide, which may be responsible for the therapeutic properties of garlic observed (Chi et al., 1982; Canogullari et al., 2010). In the last decade, garlic has been widely reported to be incorporated into poultry diets to determine any effects on poultry performance. In this review, the literature regarding the use of this natural product is discussed.  

Numerous reports have been published, advocating the beneficial effects of garlic on feed efficiency and growth of broiler chickens. According to (Mansoub, 2011), feed conversion ratio (FCR) and body weight (BW) of broilers were improved when they were fed garlic (Ig/kg) in the basal diet. (Aji et al., 2011) reported that administration of 100mg of garlic resulted in improved body weight gain at 7, 14 and 21days of treatment in broilers chicks, although feed intake, FCR and carcass yield did not change. (Kumar et al., 2010) found that a garlic supplemented diet (250 ppm) significantly increased the body weight grain of broilers chickens in a 42 days trial. In the same year, (Pourali et al., 2010), reported that garlic powder improved average daily feed intake, body weight, FCR, performance index as well as survivability. (Mahmood et al., 2009), Concluded that a basal feed containing 0.5% garlic improved FCR and body weight gain in broilers but failed to produce positive effects on carcass yield in term of dressing percentage, relative weight of heart, gizzard, liver, spleen and pancrease.(Javed et al.,2009),found that feed intake and  FCR, body weight and carcass quality (dressing percentage, breast weight and leg weight) were improved in a 35days experimental trial, when broilers were supplemented (at the rate of 10ml/litre of drinking water) with an aqueous extract of medicinal plants containing garlic. (Ramakrishna et al., (2003), suggested that garlic supplementation enhances the activity of pancreatic enzymes and provides an environment for better absorption of nutrients. (Javandel et al., 2008), observed that feeding garlic at the level of 0.125 and 0.25% resulted in higher feed intake during the starter phase of broilers although the same levels were not efficacious during the growing phase. Additionally, in this experiment, the authors did not find any difference in body weight and carcass characteristics in term of percentage of carcass, small intestines, proventriculus, gizzard, liver and abdominal fat. (Ashayerizadeh et al., 2009), Demonstrated that garlic powder added into broilers feed had a significant effect on carcass yield, but feed intake and efficiency body weight, thigh and breast weight did not change, although abdominal fat percentage decreased in garlic supplemented birds. Similarly, (Mohebbifar and Torki., (2011), reported that feeding garlic at of 0 or 2g/kg did not affect feed intake, FCR and weight gain in Ross broilers (Rahmatnejad et al., 2009), concluded that garlic given at the rate of 1000g/ ton of feed did not affect feed intake, FCR and body weight gain. (Horton et al., 1991); (Konjufea et al., 1997), could not trace any effect of garlic supplementation on the performance of broiler chicks .such a wide range of results may be attributed to the dose, duration and processing of the medicinal plants as well as the experimental conditions. (Khan et al., 2008), suggested that difference in the results determined by different authors may be due to the use of different commercial garlic products may be divided into raw garlic (Allicin rich) and processed garlic (non-Allicin rich) which differ in the active substance they contain.

            Egg production and Quality are heritable traits of major concern for breeders, industry and consumers. To improve these characteristics, correct nutritional, management and environmental practices are needed to enhance egg production and quality. Eggs are a delicate product which can be lose quality rapidly during the period of collection to consumption. Thus improvement in egg quality is of paramount importance in the field of production and management (Mahmound et al., 2010). There is a dearth literature available concerning the beneficial effects of garlic on egg quality. For example (Yalcin et al., 2006), found that egg weight increased when laying hen were fed 5 and 10g/kg garlic powder. (Khan et al., 2007), reported that egg production increased during the six weeks in which 0, 2, 6, or 8% garlic powder was fed to laying hens.(lim et al., (2006) concluded that with increasing dietary garlic powder, the Haugh unit increased linearly after two weeks. (Chowdhury et al.,2002) also reported that yolk weight responded in a quadratic manner to increasing level, of sun – dried dietary garlic paste, (canogullari et al., 2010) demonstrated that egg production increased significantly by adding 1% garlic powder in the feed of the laying hens although egg weight yolk index, shell weight, shell thickness, yolk weight did not change. In the same experiment, egg shield index and haugh unit decreased significantly in the birds supplemented with 4% garlic powder. (Yalcin et al., 2006), reported that supplementation of garlic powder had no significantly effect on egg albumen index, egg shell index, egg haugh unit value, when laying hens were fed 5 and 10g/kg garlic powder for 22 weeks. According to (Mahmond et al., 2010), egg albumin, yolk and shell weight as well as albumin height and haugh unit were improved when laying hens were supplemented with 0.25, 0.50 and 1% garlic juice.                                       
(Mottaghitalab and Taraz. 2002), showed that the inclusion of 0, 5, 10 and 15g/kg garlic powder significantly decreased yolk weight. (Reddy et al., 1991); Chowdhury et al., 2002). Concluded that supple mentation of garlic did not affect egg production. (Khan et al., 2008) ,concluded that feeding 8% dried garlic powder may result in better egg production in Densi laying hens, with no effect in egg mass and egg weight. The difference in the results of different reports may be due to the different experimental protocols and garlic preparation in their experiments (Canogullari et al., 2010).

The immune system of poultry can be broadly divided into two categories namely, the lymphoid and non-lymphoid systems, bursa of fabricius and thymus are considered to be the primary lymphoid Organs, where as spleen is usually termed as secondary lymphoid organ. The non-lymphoid parts of the immune system include cells that provide a non – specific immunological defence of the host. Blood monocytes and tissue macrophages are unique due to their ubiquitous distribution throughout the body fluids, organs and cavities (Khan et al., 2011b). Recently, (Zialarimi et al., 2011), found that aqueous extract of garlic was more effective in inhibiting E.coli culture than mint (Menthe spp.) and onion (Allium Cepa) in broiler Chicks, Suggesting the role of garlic in Suppressing pathogenic bacteria.
Several reports are available advocating the strong Immune potentiating effects of garlic. (Szigeti et al., 1998), reported that supplementing chickens with a modified product including garlic increased antibody production against Salmonella enteritidis, Pasteur rella multocida and leptospira Pomona bacteria. (Ahsan-ul-Haq et al., 1999), reported that feeding broilers at the rate of 20g/kg increased significantly antibody titre against Newcastle disease virus (NDV) and infectious bursal disease (IBD) in broiler Chicks. (Szigeti et al., 1998), found that a product containing garlic, acidifers and bacterial cell extracts enhances antibody production against NDV, where as, (Jafari et al., 2008), reported that supplementing boilers with garlic (1 or 3%) does not have any beneficial effects on antibody production. (Hanieh et al.,2010), found that feeding garlic at the level of 10g/kg diet enhanced titre against NDV and sheep red  blood cell, (RBC,) in white leghorn chickens, although such effect , were not recorded when the dose was at high as 30g/kg. In the same line ,(Dorhoi et al., 2006) observed that  macro phage engulfing RBCs percentage was higher when the laying hen were supplemented with 50ug/ml of garlic and the engulfment was low when the dose was increased to 200ug/ml. Recently, (Nidaullah et al., 2010) found that a plant mixture containing garlic at the level of 4g produced better antibody response against NDV and IBD in boilers chicks.(Rahimi et al.,2011) found that o.1% garlic in the diet of broilers improved antibody response against sheep RBC, and NDV, increased bursa of fabricious weight and spleen weight and Augmented hypersensitivity coetaneous baso philic response. (Dorhoi et al.,2006), reported that garlic supplemented birds had heavier spleen and thymus weight and white blood cells, (WBC) count . The increase in the weight of the spleen and thymus are attributed to the enhanced lymphocyte proliferation and the increase in the WBC productions. (pourali et al., 2010) showed that different concentration of garlic powder improved antibody titre against NDV virus at 14th day of age. (Hanieh et al., 2010), suggested that the immuno – modulating effect of garlic is associated with it ability to enhanced phagocytosis of peritoneal macrophages, increased production of interleukins, interferon (INF – Y) and tumour necrosis factors (TNF – a) secretary metabolism of macrophages, antigen presenting cells and antioxidant function of this plant. (Mohebbifar and Torki., 2011), demonstrated that adding 0 or 2g/kg garlic in the basal feed of Ross broilers did not affect the heterophil, lymphocyte, monocytes, eosinophil, basophil and heterophil to eosinophil ratio nor the serum antibody against NDV was positively changed. The discrepancies observed in the results are likely related to the preparation methods of garlic. In addition, the experimental design and dose of garlic used have a great deal in the differences of the results of immune functions (Hanieh et al., 2010).

In the scientific literature, the hypolipidic and hypocholesterolimic effects of garlic are well documented. (Ahsan – ul – Haq  et al., 1999), reported that feeding garlic at the rate of 20g/kg decreased blood cholesterol significantly in broiler chicks. Egg yolk cholesterol of laying hens decreased significantly in birds supplemented with I and 2% garlic powder (Canogullari et al., 2010). (Chowdhury et al., 2002), concluded that cholesterol concentration per gram of yolk decreased linearly with increasing levels of sun – dried dietary garlic paste. (Khan et al., 2007), showed that feeding dietary garlic at 2, 6 or 8% reduced egg yolk cholesterol, on average over six weeks, by 5.7, 14.3 and 23.6% respectively. (Khan et al., 2008), found that garlic powder given at the level of 8% may result in better serum and egg yolk cholesterol profile in laying hens. However (Mahmoud et al., 2010), observed that egg cholesterol did not change  when laying hens were supplemented with garlic extracts in different concentration (0, 0.25, 0.5, and 1%). If egg cholesterol can be reduced to minimum level, it would assist in the consumer perception regarding the healthiness of table eggs (Mahmond et al., 2010). Recently, in the study of (Canogullari et al., 2010), garlic powder at the rate of 1, 2 and 4% were found to reduced total lipid concentration and total triglyceride level was reduced by garlic powder supplementation at the levels of 1 and 2% garlic in laying hens (Azeke and Ekpo., 2008). Similarly, (Yalcin et al., 2006), reported a significant decrease in plasma triglycerides with the supplementation of garlic powder (Youn et al., 1996) concluded that serum triglyceride was lowered by supplementing garlic powder to the diet.
(Horton et al., 1991), found that broilers fed garlic at 10,000 mg/kg reduced plasma cholesterol in 35days treatment. Publications by (Qureshi et al., 1983b), documented that the serum cholesterol concentration in white leghorn pullets was reduced from 20 to 25% using supplements of garlic paste, solvent extracted from garlic paste and commercial garlic oil (Canogullari et al., 2010), found that 1, 2 and 4% garlic powder increased high density lipoprotein (HDL) cholesterol in laying quails. However, (Lim et al., 2006), did not found any difference in HDL – Cholesterol concentration by feeding garlic (1, 3 and 5%). (Qureshi et al., 1983b), reported a 28 – 41% reduction in low density lipoprotein (LDL) cholesterol in an experimental diet containing 3.8% garlic paste or a solvent extract of garlic paste, the residue or commercial garlic oil fed for four weeks. Recently, (Mansoub, 2011) reported reduction in total cholesterol, LDL – cholesterol and triglycerides  when broilers were supplemented with 1g/kg garlic. (Prasad et al.,2009),observed that total cholesterol triglycerides, LDL and very low density lipoprotein (VLDL) were significantly decreases, while HDL was significantly increased by garlic supplementation in chicken up to eight 8 weeks of age in comparison to control group. (Rahimi et al., 2011) noted that supplementation of 0.1% garlic decreased cholesterol, triglyceride and LDL cholesterol but increased HDL level. Recently, (Rehman et al., 2011), documented that a mixture of plants containing garlic as an active ingredient improved the cholesterol profile in terms of cholesterol, triglyceride, LDL cholesterol, VLDL cholesterol, total cholesterol to HDL ratio, LDL to HDL ratio, VLDL to HDL ratio in broiler chicken serum. (Konjufea et al., 1997), conducted an experiment on male Ross 208 which were fed a basal diet supplemented with 1.5, 3.0 or 4.5% commercial garlic powder from hatching to 21 days of age, and found that garlic powder resulted in reduced level of plasma cholesterol, liver cholesterol, breast and thigh muscle cholesterol.
The mechanism by which garlic reduces plasma cholesterol concentration is not fully understood. Some of the investigators are of the opinion that garlic depresses lipogenic and cholesterogenic activities of liver enzymes such as malic enzyme, fatly acid synthase, glucose – 6- phosphate dehydrogenases and 3 – hydroxyl – 3 – methyl – glutaryl – COA (HMG – COA) reductase (Qureshi et al., 1983a; 1983b; Youn et al., 1996; Chowdhury et al., 2002; Canogullari et al., 2010; (Mahmoud et al., 2010). This hypothesis was demonstrated when several researchers measured cholesterol – clearing enzymes. For example. (Qureshi et al., 1983a), reported a dose dependent inhibition of hepatic HMG – COA reducase and cholesterol 7a – hydroxylase and falty acid synthetase in chicken fed polar fractions of garlic powder equivalent to 1, 2, 4, 6, and 8% of fresh garlic paste. (Knojufca et al., 1997), reported that feeding 3% commercial garlic powder reduced the activities of HMG – COA reductase and cholesterol 7a – hydrotylase by 40%. Allicin has been proposed as the active compound in garlic responsible for health promotion and hypocholesterolaemic benefits (Lawson, 1998). In terms of the mechanism of action, it is believed to reduce cholesterol synthesis, and platelet aggregation and prevent thrombosis (Canogullari et al., 2010). Allicin is a volatile organic compound which has been shown to reduce serum lipids, phospholipids and total cholesterol and suppress cholesterol synthesis in chickens (Horton et al., 1991). According to (Mahmoud et al., 2010), the difference in the results may be due to allicin degradation as it is an unstable compound and poorly absorbed from the gut, Additionally, they suggested that the garlic preparation that involved heating or solvent processes may destroy active allicin.

Several studies have pointed out the possibility to use essential oils and/or their components for medical purposes as well as in the food industry for controlling micro – organisms responsible for food spoilage (Cantore et al., 2009). Today we know that the essential oils and plant extracts have broad activity against the Gram – positive and Gram – negative Bacteria and also antifungal activity (Kotzekidou et al., 2008). Garlic oil has antimicrobial activity (Feldberg et al., 1988) and a high dose of garlic could have detrimental effects on ruminal fermentation. For instance, (Busquet et al., 2005b) reported that the molar proportion of acetate was reduced by 11% and NDF digestibility was decreased by 22% when 312mg of garlic L-1 was added to in vitro batch culture rumen fermentation at a constant PH (busquet et al., 2005a). several studies have suggested that essential oils may be conserves of degradation of AMINO acid (AA) in rumen by inhibiting microbial deamination (Newbold et al., 2004).
Antibacterial properties of garlic and onion were described by Louis Pasteur. The sulphur – containing compounds from these plants act against both gram positive and gram negative bacterial (Carson, 1987). The extracts of garlic and onion are known to inhibit growth of many pathogenic fungi belonging to Aspergillus, Candida and other species (Carson, 1987).

A recent review (Srinivasan et al., 2004) shows the following results. The spices Fungreek, red pepper, turmeric, garlic, onion and ginger were found to be effective as hypocholesterolemic agents under various conditions of experimentally induced hyper cholesterolemia/hyperlipemia. Furthermore, fenugreek, onion and garlic are effective in human with hyperlipemic condition. Curcumin and capsaicin, the active principles of turmeric and red pepper, respectively, are also efficacious at doses comparable to calculated human daily intake. Turmeric and curcumin showed excellent hypo cholesteremic effect in experimental animals. However, endogenous cholesterol synthesis was not affected. Extracts of garlic and onion inhibit platelet aggregation and lower cholesterol levels. The raw form is more effective than the cooked form. About 50g of onion and garlic corresponding to 5 – 6 cloves per day may be adequate to bring these beneficial effects.
Other work also documents hypo cholesterolemic effects of spices. Fenugreek seeds were hypo cholesterolemic in rats with hyperlipidemia induced by either high fat (Singhal et al., 1982) or a high cholesterol diet (Sharma, 1984, 1986). Defatted fenugreek seed was effective in diabetic hyper cholesterolemia in dogs (valette et al., 1984) and in humans (Sherma, 1986). The hypolipidemic effectiveness of tumeric/curcumin (Srimal, 1997), red pepper/capsaicin (Suzuki and Iwai, 1984; Govindarajan and Satyanarayana, 1991; Surh and Lee, 1995; Majid et al., 1997) and of onion and garlic (Fenwick and Hanley, 1985; Carson, 1987; Jain and Apitz castro, 1994) has been periodically reviewed in recent years by different authors .
(Kleijnen et al., 1989) reviewed the Clinical research concerning garlic and its preparations. Their main concern is that large amounts of garlic (up to 20 cloves) are needed to prove clinical effectiveness. This is indeed true because large quantities are reguired to provide relatively very small amounts of active oils or other derivatives. But with the introduction of dehydrated garlic powder containing a standardized level of the parent sulphur compound, alliin, effective clinical work could be undertaken with a relatively low and acceptable daily dosage of 300 – 900mg (= 1 clove of garlic) this level produces a consistent 10% - 13% reduction in blood cholesterol and triglycerides.
In a resent study, dietary supplementation with aged garlic extract showed better beneficial effects, relative to flesh garlic, on the lipid profile and blood pressure of moderately hyper cholesterolemic subjects (Steiner et al., 1996). In another study (Adler and Holub, 1997), garlic supplementation significantly decreased both total and LDL cholesterol in hyper cholesterolemic subjects. Co-administration of garlic with fish oil had a better beneficial effect on serum lipid and lipoprotein concentrations by providing a combined lowering of total cholesterol, LDL cholesterol, and Triglyceride concentration as well as the rations of total cholesterol to HDL cholesterol. According to (Lin, 1994), the antiplatelet aggregation, the antiplatelet adhesion and the anti proliferation properties of aged garlic extracts appear to contribute more to cardiovascular protection than do the hypolipodemic properties. Apart from the hypo cholesterolemic effect on overall lipid metabolism under different conditions of lipemia has also been reported (Srinivasan and satyanarayana, 1987, 1988; Sambaiah and Satyanarayara, 1982).

Garlic and onion and other  spices that have been widely used for their anti-diabetic potential. both spices were shown to be hypoglycemic in different Diabetic animal models and in limited human trails. The hypoglycemic potency of garlic and onion has been attributed to the sulphur compounds, namely di (2 – propenyl) disulphide and 2 – propenylpropyl disulphide, respectively (Kumudkumari et al., 1995; Augusti and Sheela, 1996). Animal studies indicate that the isolated compounds possess as much as 60% - 90% of the hypoglycemic action probably involves direct or indirect Stimulation of secretion of insulin by the pancreas. In addition, it is also suggested that these disulphide compounds have an insulin – sparing effect by protecting – SH inactivation by reacting with endogenous thiol – containing molecules such as cysteine, glutathione, and serum albumins (Srinivasan, K. 2004).
Garlic (Allium Sativum) is reported to have many biological activities, including protective role in cardiovascular function (Mukherjee et al., 2009) as an antihypertensive (Ried et al., 2008). Allicin, a major constituent of garlic, was evaluated for its antihypertensive effects. Chronic oral administration of allicin lowered blood pressure in hypertensive rats (Ali et ai., 2000). Allicin also caused pulmonary vasodilatation in lung at rat (Kin – park and KU, 2000).
It have been reported that garlic and garlic extracts, through their antioxidant activities prevent free radical damage in the body. (Chung, 2006) investigated antioxidant properties of garlic compounds (Alliin, Allylcysteine, Allyl Disulphide and Allicin) prepared by chemical synthesis or purification. Alliin Scavenge superoxide, while Allyl cysteine and Allyl sulphide did not scavenge superoxide, Allicin suppresses the formation of superoxide by the xanthine / xanthine oxidase system, likely through thiol exchange mechanism. Garlic compounds such as Alliin, Allyl cysteine and allyl disulphide scavenge hydroxyl radicals. Allin, allicin and allyl cysteine did not prevent microsomal lipid peroxidation but alliin and allyl cysteine were scourer of hydroxyl and allyl disulphide was a lipid peroxidation terminator. In summary, allyl disulphide, alliin, allicin and allyl cysteine indicates different patterns of anti-oxidants as protective compounds against free radicals damage (chung, 2006).

Spices are well recognized to stimulate gastric function. They are generally believed to intensify salivary flow and gastric juice secretion and, hence, aid in digestion (Glatzel, 1968). Spices like turmeric are know to reduce the pungency of the food and irritation to stomach. Turmeric has the property of increasing the mucin content of the gastric juice. Spices such as ginger, mint, Ajowen, Cumin, fennel, coriander, and garlic are used as ingredients of commercial digestive stimulants as well as of home remedies for digestive disorders. Earlier reports on the digestive stimulant action of spices are largely empirical; its only in recent years that this beneficial attribute of spices has been authenticated in exhaustive animal studies (Platel and Srinivasan, 2004).
Animal studies have revealed that a good number of spices, when consumed through diet, bring about an enhanced secretion of bile with a higher bile acid content, which plays a vital role in fat digestion and absorption (Bhat et al., 1984, 1985; Sambaiah and Srinivasan, 1991:Platel and Srinivasan, 2000). Spices that stimulate bile acid production by the liver and its secretion into bile include curcumin (Turmeric), capsaicin (red pepper), ginger, cumin, coriander, Ajowen, fenugreek, mustard, onion, and tarnarind. Spices such as curcumin, capsaicin, piperine, ginger, and mint have also been shown to stimulate pancreatic digestive enzymes like lipase, amylase, trypsin, and chymotrypsin, which play a crucial role in food digestion (Platel and Srinivasan, 2000a, 2001). A few spices have been shown to have beneficial effect on the terminal digestive enzymes of small intestinal mucosa (platel and sririvasan, 1996, 2000a,). Thus, many of the common spices act as digestive stimulants by enhancing biliary secretion of bile acids, which are vital for fat digestion and absorption, and by stimulating the activities of pancreatic and intestinal enzymes involved in digestion.

Garlic is yet another spice widely studied in recent years for its chemo preventive potential. Epidemiological studies have shown that higher intake of allium products is associated with reduced risk of several types of cancers, especially stomach and colorectal (Fleis chauer and Arab, 2001). These epidemiological findings are well correlated with several laboratory investigations. Several mechanisms have been proposed to explain the cancer – preventive effects of garlic and its organosulphur compounds, As recently reviewed (sengupta et al., 2004). Suggested mechanisms include inhibition of mutagenesis, modulation of enzyme activities that suppress bioactivation of carcinogen molecules, inhibition of carcinogen-­DNA adducts formation, free radical scavenging, inhibitory effects on cell proliferation and tumor growth, and induction of a large apoptosis. Although there is a large body of evidence supporting these mechanisms, they are still speculative, and further research is needed to support causality between such properties and cancer preventive activity in experimental animals. The important observation on the cancer preventive potential of garlic and its sulphur compounds are summarized in the table below .

Garlic and cancer prevention
Rat/Liver, mammary gland
Dietary garlic powder
DMBA, nitrosamine
in vivo inhibition of DNA adduct
Liu et al., 1992, 1992a; Lin et al., 1992.
Rat/Colon, esophagus
Wargovich et al., 1988.
Garlic, S-Allyl cysteine, DADS
Delayed onset
Schaffer et al., 1996.
Dietary garlic powder
Park et al., 2002
Sumiyoshi and wargovich, 1990
Garlic oil-topical
Belman, 1983
Surh et al., 1995
suppression Inhibition
Nishikawa et al., 2002
Arora et al., 2004
Hamster/Buccal pouch
S-Allyl cysteine
Balasenthil et al., 2001

Crushed fresh garlic: 5g

Inhibition of nitrosation
Mei et al., 1989

China (Cangshan Country)
Garlic: 20g/day

decreased  gastric cancer mortality, decreased NO2 in gastric juice.
Mei et al., 1985; You et al., 1989
Garlic consumption

Decreased incidence of stomach and colo-rectal cancer
Fleischauer and Arab, 2001
Garlic consumption

Lesser incidence of prostate cancer
Hsing et al., 2002

            From the overview of Garlic, It has high nutritive value, Anti-microbial activity, anti-oxidant, hypo cholesterolemic, Anti diabetic, Anti-mutagenic and anti – Carcinogenic, Anti – hypertensive, immuno – modulating activities. Garlic may be a useful alternative to antibiotic in poultry production due to it wide range safety margin. Garlic may be a useful alternative to antibiotic in poultry production due to it wide range safety margin.

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