Effect of Using Garlic on the Economical and Physiological Characteristics of Broiler Chickens

This investigation aimed to evaluate the beneficial effects of garlic powder as a phytogenic supplement on broilers chickens' performance. The assumption that garlic could improve some economic and performance characteristics of broiler chickens (i.e., body weight, feed intake, water intake, feed conversion ratio, feeding cost, carcass yield, and mortality rate) was tested. A total of 400 one-day-old chicks of mixed sex (Hybrid) were weighed and randomly assigned to four treatment groups, each with four replicate pens of 25 chicks. The dietary treatments included the basal diet (control), control + 2.5 kg/ton garlic, or control + 5 kg/ton garlic or 7.5 kg/ton garlic as powder. The results of the study revealed that incorporation of garlic powder in broiler diets as feed additive significantly enhanced growth, economic and productive performance of these chickens. Physiological measurements (body weight, weight gains, feed intake, feed conversion ratio, carcass weight and internal organs) showed better performance of garlic treated chickens compared with control group under same rearing system. The results similarly showed lower susceptibility to diseases and medicament treatment consequently; lower mortality rate compared to control groups. Furthermore, blood and meat analysis showed lower cholesterol, Triglyceride, LDL, and, HDL levels compared with control group. The study concluded that garlic could be effectively used in broilers feeding to replace antibiotic as a growth promoter.


INTRODUCTION
Feed additives have been widely used in poultry nutrition as a tool for increasing animal productivity [1], improving performance and, the health of broiler chickens [2]. Most of the plant parts contain compounds with proven antibacterial, antiviral, antiparasitic, antifungal properties and have antihypertensive, hypoglycemic, antithrombotic, antihyperlipidemic, anti-inflammatory and antioxidant activity. Garlic (Allium Sativum) has been found that lower serum and liver cholesterol [3], inhibit bacterial growth [4], inhibit platelet growth and reduce oxidative stress. In pursuit of improved chicken healthiness and to fulfill consumer expectations using natural feeding supplements mainly herbs will be the best alternative [5].
Feed additives are used to improve feed intake and, increase growth rate in broilers [6]. Garlic is a perennial herb with a bulb divided into cloves [7] and belongs to the family Amaryllidaceae and genus Allium. Garlic has several valuable effects on both humans and animals through having antibiotic, antifungal, anticancer, antioxidant, immunomodulatory, anti-inflammatory, hypoglycemic and cardiovascular-protecting antiviral [8][9][10][11]. It is extensively used in all parts of the world as a spice and herbal medicine for prevention and treatment of a variety of diseases ranging from infection to heart diseases. Previous studies showed that supplementation of garlic to broiler diets motivating immune system, and digestion efficiency of birds due to the abundant of bioactive compounds present in garlic such as alliin, daillylsulphide, and allicin [11][12][13]. These components possess antimicrobial activity [14] that could be responsible for the growth promoting the effect of garlic. Elagib et al. [15] reported that the best performance was gotten by a group of birds fed on a diet containing 3% garlic powder and they got the highest feed consumption. Garlic supplementation at 0.25% in broiler finisher diets enhanced the feed conversion ratio, and hence growth 1 The article is published in the original.

ANIMAL HUSBANDRY
rate of the birds and the best performance was attained by the group of birds fed on a diet containing 3% garlic powder had best feed conversion efficiency [16]. Tollba and Hassan [17] reported that garlic improved broiler growth, feed conversion ratio (FCR) and decreased mortality rate. Onibi et al. [18] reported that powdered garlic at 0.5% might integrate as a growth promoter in the ration of Japanese quails.
To the author's knowledge, this is the first study carried out to investigate the effect of using garlic in a basal diet of broilers on the overall performance, reduce the spread of diseases and parasites in poultry cycles. For that reason, we aimed to examine the effect of adding garlic powder in broiler diet on its productivity and physiological characteristics (i.e., body weight, feed intake, water intake, feed conversion ratio, feeding cost, carcass yield, and mortality rate). The results of this investigation will be used for further research studies in layers and other animal species (Turkey or sheep and goats… etc.).

MATERIALS AND METHODS
The experiment was conducted at Livestock Field Research Station; Department of Animal Production, Faculty of Agriculture, at Jerash University/Jordan. The care and use of experimental animals act by local animal welfare laws, guidelines, and policies.

Animals and Dietary Treatments
Fourteen hundred one-day-old chicks of mixed sex (Hybrid) were weighed and randomly assigned to each of the four treatment groups, each with 4 replicate pens of 25 chicks. The dietary treatments included the basal diet (control), control + 2.5 kg/ton garlic, or control + 5 kg/ton garlic or 7.5 kg/ton garlic as powder. The basal diet was formulated according to nutrient requirements of broilers provided by National Research Council [19]. Birds were served a starter diet from day 0 to 21 and grower diet from day 22 to 42. Chicks were raised in floor pens (120 × 120 × 80 cm) for six weeks. Water and feed were offered freely throughout the entire experimental period that lasting for 42 days. The lighting program consisted of a period of 23 h light and 1 h of darkness. The ambient temperature in the experimental house was maintained at 32°C during the first week and gradually decreased by 3°C in the second and third weeks, and finally fixed at 22°C after that. Both groups either control or treatment groups were vaccinated according to vaccination schedule that is used in Jordanian farming under normal rearing system according to the following vaccination program. (d 1 and 7: Infectious Bronchi and New Castle, d 14: Gumboro; d 21: New Castle vaccine). During the experimental period, no medicaments were offered to the chicken's groups either controlled or treated with garlic.

Performance and Carcass Components
Body weights of birds were determined every week. Feed intake and weight gain were recorded during a 7 d period on a per cage basis, and feed conversion ratio (FCR) was calculated. Mortality was recorded as it occurred and was used to adjust the total number of birds to determine the total feed intake per bird and FCR. At 42 d of age, two birds per replicate were randomly chosen, based on the average weight of the group and slaughtered through cutting carotid arteries. Carcasses weights, dressing percentages, carcass cuts that included: wings, back, breast and legs, abdominal fat were weighed. Internal organs (Crop, proventriculus, gizzard, liver, heart, and small intestine) were weighed separately. The length of small intestine and the weight were recorded. Meat samples from (Breast, leg, liver) after boneless, were separately ground in a meat grinder and samples from each part were used for dry matter, protein and fat determination. Cecal microbial count and populations, mortality rate, meat sensory quality test, and intestinal lesion scoring were also measured with a veterinary specialist. Blood samples were collected after slaughtering of the chickens into heparinized tubes from 8 chicks within treatments deprived of feed for 24 h at the end of the experiment (42 d). Serum was obtained by centrifuge blood at 4000 round per minute for 10 min to evaluate s cholesterol, triglycerides, HDL, LDL, total protein, and albumin.

Statistical Analysis
Data from the randomized design were subjected to an analysis of variance using the MIXED model procedure of SAS. An ANOVA with repeated measures was used. Tukey-Kramer test separated the mean differences among different treatments. A level of (P < 0.05) was used as the criterion for statistical significance. In the model, the performance traits of the birds were included as dependent variables. The independent fixed effects consisted of the effect of treatment (control or garlic supplementation), the age in a week and the respective interaction. The bird was included as random effect.
where Y ijk is the observation value (Performance traits); μ is the overall mean; T i is the effect of the treatment (control vs. garlic supplementation); A j is the effect of the age (week); TA ij is the effect of the interaction between treatment and age, and e ijk is the residual error.

RESULTS
Results showed that garlic powder improved bird's body weight. The body weight increased significantly every week with higher rates when garlic powder offered at 5 kg/ton level. Furthermore, using garlic showed the earlier effect on body weight at the second week of age (Table 1). Feed intake significantly (P < 0.05) tended to be higher in the birds that fed on garlic powder diets compared to the control group under same rearing system ( Table 2).
The internal organs including the digestive tract and other inedible parts, which form a large part of the weight further, have heavier weight when garlic was offered compared to control group. Carcass weight showed the better characteristic of treated chicken with garlic compared with the control group under same rearing system.
Increasing body weight resulted in increasing carcass and eviscerated yields at 5 kg/ton of used garlic powder (Table 3). Also, using garlic powder resulted in increased body weight changes and improved feed conversion ratio compared with control group birds.
Using garlic powder promotes small intestine length in comparison with control groups and depressed in lesion scores of the small intestine and lowering the coccidian eggs account when garlic powder is added to the ration (Table 4).
Using garlic in broiler diet reduced the blood cholesterol, Albumin, Triglyceride, and HDL as compared to the standard levels. As shown in the Table 5, chicken those have garlic in their feeding are with lower cholesterol, Triglyceride, LDL, HDL levels compared with control groups.

DISCUSSION
Garlic has several beneficial effects on both humans and animals because it is having antimicrobial, antioxidant as well as antihypertensive properties. These functions were endorsed to bioactive components present in garlic, one of which is a sulfur-containing organic compound known as diakylpolysufides that possess antimicrobial activity that could be responsible for the growth promoting the effect of garlic [8]. Similar results obtained by a study conducted by Safa et al., [20] that showed, using a diet with 3% garlic powder had significantly (P < 0.05) heavyweight  gain, highest feed intake, best feed conversion ratio with highest dressing and breast percentages. Improved feed intake was noticed in chicks fed with garlic powder compared with the control chicks under same rearing system. Improvement of body weight could be attributed to the growth-promoting effect of garlic. Similar results obtained by Elagib et al. [15] who reported that the best performance was attained by the group of birds fed on a diet containing 3% garlic as a powder. Furthermore, Racesi et al. [21] indicated that diet supplemented with garlic powder at level 1-3% had significantly feed intake compared to the control diet without garlic.
Using garlic powder improved feed conversion ratio in this investigation that can be attributed to allicin active ingredients in garlic that promotes the performance of intestinal flora, thereby improving digestion and enhance the utilization of energy. Also, the better-feed conversion ratio can be attributed to the antibacterial properties of the garlic powder, which caused better absorption of the nutrients in the gut and finally leading to improvement in feed conversion ratio. Tollba and Hassan [17] reported that added garlic to broiler ration improved broiler growth and feed conversion ratio (FCR) and decreased mortality rate. Data presented in Table 5 shows that addition of garlic in the diet reduced the blood cholesterol, Albumin, Triglyceride, and HDL levels compared with standard levels that reflect the possible mechanism of the lowering action of S-allyl cysteine sulfoxide which is found in garlic. Prasad et al. [22] reported similar findings were total cholesterol, Triglycerides, and LDL was significantly decreased by adding Garlic to broiler ration. It can be concluded from our investigation that; incorporation of garlic powder in broiler diet as feed additive significantly enhanced growth, economic and productive performance of broiler chicks. Physiological measurements (body weight, weight gains, feed intake, feed conversion ratio, carcass weight and internal organs) showed the better characteristic of chicken fed with garlic compared with control group under same rearing system. Our investigation showed lower mortality rate, lower susceptibility to diseases and medicament treatment when we used garlic. Meat and blood characteristics showed lower cholesterol, Triglyceride, LDL, HDL levels compared with control group. Furthermore, the economic evaluation of the experimental diets indicated that the diet with garlic powder showed higher profitability as compared to the control group.