Effects of Dietary Garlic Powder on Cholesterol Concentration in Native Desi Laying Hens
Sohail Hassan Khan,
Muhammad Ashraf Anjum
The research was conducted to evaluate the potential
for local dietary garlic to influence egg yolk and blood cholesterol concentrations
and overall performance of native desi layers. Forty 30-week-old desi
layers (ten hens per diet) were caged individually and fed diets supplemented
with 0 (control), 2, 6 and 8% oven dried garlic powder (at low temperature
i.e., 55°C) for 6 week. The results showed that differences among
diets in weight gain and egg production were found significant (p<0.01)
as averaged over 6 week. However, no differences (p>0.05) were observed
among diets in feed intake, feed efficiency, egg weight and egg mass with
increasing levels of dietary garlic. Serum and egg yolk cholesterol concentrations
decreased (p<0.05) with increasing levels of dietary garlic. It may
be concluded that dried garlic powder in the diets of desi laying hens
reduced serum and yolk cholesterol concentrations and dietary garlic powder
had better effects on layer performance.
Garlic (Allium sativum) has acquired in the folklore of many
cultures as a therapeutic agent (Amagase et al., 2001). According
to folk medicine, garlic was used to treat cardiac disease (Essman, 1984).
Some clinical reports, including meta-analyses, have described the hypocholesterolemic
effect of garlic in human (Warshafsky et al., 1993; Silagy and
Neil, 1994). Some studies, however, suggested that commercial garlic oil,
garlic powder and commercially available garlic extract may not be hypocholesterolemic
(Berthold et al., 1998; McCrindle et al., 1998). Although
the reason for this is unknown, it likely relates to preparation methods,
the stability of chemical components and the duration of the study (Amagase
et al., 2001).
Animal studies suggest that garlic has potential hypolipidemic, hypoglycemic,
hypotensive and hypothrombotic properties (Bordia et al., 1975;
Shoetan et al., 1984). The biochemically active constituent of
garlic is allicin (thio-2-propene-1-sulfinic acid S-allyl ester) and its
production from an odorless precursor alliin is catalyzed by an enzyme
alliinase or alliin lyase and is responsible for smell of garlic (Murad
and Baseer, 1997). Moreover, chronic exposure to small amount of tellurium
found in garlic may reduce endogenous cholesterol production through inhibition
of hepatic squalene epoxidase (Barhagallo et al., 1998). Garlic
paste (3.8%), solvent fractions, or garlic oil equivalent to this amount
reduced serum cholesterol by 18 and 23% in broilers and 12-week-old leghorn
pullets, respectively, when diets were fed for 4 week (Qureshi et al.,
1983b). Experiments in which garlic was fed to 5-week-old male broilers
for 3 week and in vitro studies with chicken hepatocytes exposed
to polar fractions of garlic powder (garlic equivalent to 1, 2, 4, 6 and
8% fresh garlic paste) showed a dose-dependent inhibition of hepatic HMG-CoA
reductase, cholesterol 7α-hydroxylase and fatty acid synthetase (Qureshi
et al., 1983a). Sklan et al. (1992) reported decreased
hepatic cholesterol concentration in chicken when 2% garlic was fed for
14 days. However, Birrenkott et al. (2000) reported that 3% garlic
powder, did not have any significant effect on yolk and serum cholesterol
concentrations when laying hens were fed diets for 8 months. Reddy et
al. (1991) reported that egg production; egg mass, body weight, feed
intake and feed efficiency were not affected during the 8 week when 0.02%
garlic oil was fed to the Babcock B-300 strain. Egg yolk cholesterol concentrations
have been shown to vary depending on the genetic strain of the laying
hens (Han and Lee, 1992).
In Pakistan, rural poultry is one of the important segments of poultry
production which contributes about 42 and 60% in poultry meat and eggs
produced in the country, respectively (Sahota and Bhatti, 2003). Most
of work on garlic supplementation has been carried out in commercial layers
(Rehman, 2001; Ashfaq, 2001) but there is no research done on native desi
layers in Pakistan. Therefore, the current study was planned to characterize
the hypocholesterolemic effects of various levels of local oven-dried
garlic powder in the diets of native desi laying hens.
MATERIALS AND METHODS
Experimental Birds and Diets
Forty, 30-week-old hens of desi strain (ten birds per diet) were used
in this study. Hens were caged individually and provided with 16 h of
light daily. All birds were fed isonitrogenous and isocaloric mash diets
for 6 weeks. The basal diet was formulated to meet the nutrient requirements
of laying hens (NRC, 1994). The basal diet was supplemented with 0 (control),
2, 6 and 8% oven dried garlic powder. The composition of the experimental
diets is shown in Table 1. The nutrient composition of
experimental diets is given in Table 2. The proximate
analysis and cholesterol concentration of each experimental diet was done
at feed testing laboratory of Poultry Research Institute, Rawalpindi.
The other nutrients were calculated on the basis of available nutrient
composition of each ingredient. Feed and water were provided ad libitum.
Source and Preparation Methods for Dietary Garlic
Locally produced garlic bulbs were purchased from market. The garlic
was harvested in April-May. The age of the bulbs, when dried, was 2 to
4 months. Fresh garlic bulbs were cut into pieces with husk. Then it was
subsequently thinly spread on hot air oven trays at 55°C. Drying process
was continued for 20-24 h to ensure the appropriate consistency for the
grinding to make a powder form. Diets were prepared the following day
and were stored at room temperature for a maximum of 6 weeks.
||Composition of experimental basal diet
Birds were randomly assigned to four diets and fed daily. Body weight
was measured weekly and body weight gain was recorded. Weekly feed consumption
was recorded and feed efficiency was calculated during the 6 weeks experimental
period. Daily egg production was recorded and egg weights were determined
weekly. Egg mass was calculated on the basis of egg production and egg
weight. Eggs were collected weekly from each bird for cholesterol analysis
beginning at the 21 day of feeding.
Blood was also collected from each bird weekly beginning at the 21 day
of feeding from the wing vein using sterilized syringes and needles. Serum
was isolated 4 to 6 h after blood collection. Serum samples were maintained
at -5°C for upto 2 day until cholesterol analysis. For extraction
of yolk and diet lipids, one gram of yolk was placed into a centrifuge
tube. Fifteen milliliters of chloroform: methanol (2:1 v/v) was added,
blended on a vortex mixture and allowed to extract for 12 h. Diet lipid
was also extracted by the same method using a 5 g sample with 40 mL of
Serum, extracted yolk and diet samples were analyzed for cholesterol
according to the colorimetric method of Abell et al. (1952). Diets
were analyzed for dry matter, crude protein, crude fat and crude fibre
according to the AOAC (1980).
Data were statistically analyzed by using Completely Randomized Design.
Duncan`s Multiple Range tests were used to compare the treatment means
(Steel and Torrie, 1982).
RESULTS AND DISCUSSION
Cholesterol concentrations in all diets were observed low and similar
to those found in the control diet (Table 2). The first
2 week that garlic was added as a supplement to the diet allowed the birds
to be acclimatized with the experimental diets.
The birds fed diets containing garlic gained more weight (p<0.01) than
those of birds fed diets without garlic (Table 3). Similar
trend was observed in egg production. However, feed consumption, feed
efficiency, egg weight and egg mass were not affected by diet (p>0.05)
as averaged over the 6 week period (Table 3). The results
of the present study are in line with the findings of Samanta and Dey
(1991), who reported that Japanese quails gained more weight and egg production
(p<0.05) without affect on feed consumption and feed efficiency with
garlic powder. This effect was attributed to allicin, an active component,
present in garlic powder which inhibits the growth of pathogenic bacteria
and aflatoxin producing fungi. Ashfaq (2001) also reported that supplementation
of garlic powder had non-significant (p<0.05) effect on egg weight
in commercial layers. Reddy et al. (1991) however, reported that
body weight gain and egg production in Babcock layer with 0.02% garlic
oil was not affected during the 8 weeks trial. The reason of this difference
might be the use of low level of garlic concentration and commercial garlic
oil. El-Habbak et al. (1989) reported that egg weight in commercial
layers increased with supplementation of ethanol extracted garlic because
of egg laying rate was decreased. However in our study, egg laying rate
was increased with supplementation of garlic powder.
||Nutrient composition of experimental diets after supplementation
of garlic powder
||Effects of dietary garlic on performance of desi
|abc: Means with the different superscripts
within rows are significantly different (p<0.01); A: 0% garlic;
B: 2% garlic; C: 6% garlic; D: 8% garlic
||Effects of dietary garlic on serum cholesterol concentrations
in desi laying hens (mg/100 mL)1
|abc: Means with the different superscripts
within column are significantly different (p<0.01); 1:
Data are reported at least square means n = 6
Blood Serum Cholesterol
Serum cholesterol concentrations decreased (p<0.01) with increasing
levels of garlic powder in weeks 3, 4, 5 and 6 of the study (Table
4). In this study, 2, 6 and 8% garlic powder reduced serum cholesterol
concentrations on average over 6 weeks by 20.6, 38.12 and 50.62%, respectively.
Plasma cholesterol was reduced by 30% when rats were fed diets supplemented
with 2 or 3% garlic powder (Myung et al., 1982). Qureshi et
al. (1983a) reported that diets equivalent to 1, 2, 4, 6 and 8% garlic
paste reduced serum cholesterol by 18, 21, 21, 24 and 25%, respectively,
in male broiler chickens. Similarly, in another study, Qureshi et al.
(1983b) also reported that serum cholesterol concentration in White Leghorn
pullets was reduced from 20-25% with supplementation of garlic paste,
a solvent extracted garlic paste and commercial garlic oil. This reduction
in cholesterol concentration with supplementation of garlic was attributed
to the inhibition of fatty acid synthesis; organic tellurium compounds
and allicin found in garlic might contribute to lower serum cholesterol
by inhibiting squalene epoxidase needed in the synthetic pathway of cholesterol.
The cholesterol concentrations in desi laying hens fed the control diet
in the current study were higher (157-160 mg/100 mL) than those reported
by Bhatti et al. (2003), who observed 140 mg/100 mL plasma cholesterol
in desi hens when fed similar levels of crude fibre as the current study.
This variation may be due to differences in analytical techniques and
ages of birds (Yeh Suhni et al., 1996).
Egg Yolk Cholesterol
Cholesterol concentrations per gram of yolk decreased (p<0.01) with
increasing levels of garlic powder in the diet (Table 5).
Dietary garlic at 2, 6 and 8% reduced egg yolk cholesterol, on average
||Effects of dietary garlic on egg yolk cholesterol concentrations
in desi laying hens (mg g-1)1
|abc: Means with the different superscripts
within column are significantly different (p<0.01); 1:
Data are reported at least square means n = 6
6 weeks, by 5.7, 14.28 and 23.57%, respectively. Sharma et al.
(1979) also reported that egg yolk cholesterol was reduced by 4.1 or 5.5%
when laying hens were fed 1 or 3% garlic powder for 3 weeks. Similarly,
egg yolk cholesterol was decreased by 7.28 and 6.83% through feeding diets
containing 5 and 10% of Amaranthus (herbs) which smells like garlic (Angelovicova,
1997). Yolk cholesterol values of desi birds were found lower in the current
study, when hens were comparable with those of Jiang et al. (1991),
who reported 14.6 mg g-1 yolk using the same procedure in White
Some earlier studies have suggested that commercial garlic oil, garlic
powder and commercially available garlic extract may not be hypocholesterolemic
(Berthold et al., 1998; Isaacsohn et al., 1998; McCrindle
et al., 1998). Some contradictory results about hypocholesterolemic
effect of dietary garlic might be due to use of different commercial garlic
products. The different commercial garlic products may be divided into
allicin-rich products and non-allicin rich products. The former are made
from raw garlic and the latter are made from processed garlic All may
differ significantly in the substances they contain (Kasuga et al.,
2001).The use of oven dried (at low temperature i.e., 55°C) garlic
powder in the present study maximized the possibilities of the presence
of active components.
It may be concluded that supplemental oven dried garlic powder decreased
serum and yolk cholesterol concentrations without adverse effect on layer
performance. Oven dried garlic powder up to 8% may be used as a hypocholesterolemic
agent in practical layer diets.
Abbel, L.L., B.B. Levey, B.B. Brodie and F.E. Kendall, 1952.
A simplified method for the estimation of total cholesterol in serum and demonstration of its specificity. J. Biol. Chem., 195: 357-366.Direct Link |
Amagase, H., B.L. Petesch, H. Matsuura, S. Kasuga and Y. Itakura, 2001.
Intake of garlic and its bioactive components. J. Nutr., 131: 955S-962S.PubMed | Direct Link |
Angelovicova, M., 1997.
Reduced cholesterol content in market eggs as influenced by diets with Amaranthus (Amaranthus hypochondriacus
). Acta-Zootechnica, 53: 81-87.Direct Link |
Official Methods of Analysis. 3rd Edn., Association of Official Analytical Chemists, Washington, DC
Ashfaq, M., 2001.
Effect of a dietary mixture of garlic powder (Allium sativum
) and ground kalongi (Nigella sativa
) on the performance of layers. M.Sc. Thesis, Faculty of Animal Husbandry, Univ. Agric., Faisalabad, Pakistan.
Barhagallo, C.M., M.R. Averna, G. Frada, D. Noto, G. Cavera and A. Notarbartolo, 1998.
Lipoprotien profile and HDL: Subfractions distributions in centenarians. Gerontology, 44: 106-110.CrossRef | PubMed |
Berthold, H.K., T. Sudhop and K. von Bergmann, 1998.
Effect of a garlic oil preparation on serum lipoproteins and cholesterol metabolism: A randomized controlled trial. J. Am. Med. Assoc., 279: 1900-1902.PubMed | Direct Link |
Bhatti, B.M., T. Talat and R. Sardar, 2003.
Estimation of serum glucose, cholesterol and uric acid contents and proximate analysis of meat in different strains of chickens. Pak. J. Vet. Res., 1: 26-28.Direct Link |
Birrenkott, G., G.E. Brockenfelt, M. Owens and E. Halpin, 2000.
Yolk and blood cholesterol levels and organoleptic assessment of eggs from hens fed a garlic-supplemented diet. Poult. Sci., 79(Suppl. 1): 75-75.
Bordia, A., H.C. Bansal, S.K. Arora and S.V. Singal, 1975.
Effect of the essential oils of garlic and onion on alimentary hyperlipemia. Atherosclerosis, 21: 15-18.CrossRef | PubMed | Direct Link |
El-Habbak, M.M., E. Saleh, M.S. Arbid, A.G. Hegazi and H. Sofi, 1989.
Influence of garlic (Allium sativum
) on some biological and biochemical changes in Japanese quails with special reference to its hypocholesterolaemic activity. Archivfur Geflugelkunde, 53: 73-79.
Essman, E.J., 1984.
The medical uses of herbs. Fitoterapia, 55: 279-289.
Han, C.K. and N.H. Lee, 1992.
Yolk cholesterol content in eggs from the major domestic strains of breeding hen. Asian-Aust. J. Anim. Sci., 5: 461-464.
Isaacsohn, J.L., M. Moser, E.A. Stein, K. Dudley, J.A. Davey, E. Liskov and H.R. Black, 1998.
Garlic powder and plasma lipids and lipoproteins: A multicenter, randomized, placebo-controlled trial. Arch. Int. Med., 158: 1189-1194.Direct Link |
Jiang, Z., M. Fenton and J.S. Sim, 1991.
Comparison of four different methods for egg cholesterol determination. Poult. Sci., 70: 1015-1019.Direct Link |
Kasuga, S., N. Uda, E. Kyo, M. Ushijima, N. Morihara and Y. Itakura, 2001.
Pharmacologic activities of aged garlic extract in comparison with other garlic preparations. J. Nutr., 131: 1080S-1084S.Direct Link |
McCrindle, B.W., E. Helden and W.T. Corner, 1998.
Garlic extract therapy in children with hypercholesterolemia. Arch. Pediatt. Adolesc. Med., 152: 1089-1094.PubMed | Direct Link |
Murad, K. and A. Baseer, 1997.
Garlic (Allium sativum
): A review of controlled studies. Hamdard Medicus., 11(4).
Chi, M.S., E.T. Koh and T.J. Stewart, 1982.
Effects of garlic on lipid metabolism in rats fed cholesterol or lord. J. Nutr., 112: 241-248.PubMed |
Nutrient Requirements of Poultry. 9th Edn., National Academy Press, Washington, DC., USA., ISBN-13: 9780309048927, Pages: 155Direct Link |
Qureshi, A.A., N. Abuirmeileh, Z.Z. Din, C.E. Elson and W.C. Burger, 1983.
Inhibition of cholesterol and fatty acid biosynthesis in liver enzymes and chicken hepatocytes by polar fractions of garlic. Lipids, 18: 343-348.CrossRef | Direct Link |
Qureshi, A.A., Z.Z. Din, N. Abuirmeileh, W.C. Burger, Y. Ahmad and C.E. Elson, 1983.
Suppression of avian hepatic lipid metabolism by solvent extracts of garlic: Impact on serum lipids. J. Nutr., 113: 1746-1755.PubMed | Direct Link |
Reddy, R.V., S.F. Lightsey and D.V. Maurice, 1991.
Effect of feeding garlic oil on performance and egg yolk cholesterol concentration. Poult. Sci., 70: 2006-2009.CrossRef | Direct Link |
Rehman, M.S., 2001.
Effect of different levels of dietary garlic powder (Allium sativum
) on the performance of layers. M.Sc. Thesis, Univ. Agric., Faisalabad, Pakistan.
Sahota, A.W. and B.M. Bhatti, 2003.
Productive performance of desi field chickens as affected under deep litter system. Pak. J. Vet. Res., 1: 35-38.Direct Link |
Samanta, A.R. and A. Dey, 1991.
Effect of feeding garlic (Allium sativum
Linn.) as a growth promoter in Japanese quails (Coturnix coturnix japonica
) and its influence on dressing parameters. Indian J. Poult. Sci., 26: 142-145.
Sharma, R.K., R.A. Singh, R.N. Pal and C.K. Aggarwal, 1979.
Cholesterol contents of chicken eggs as affected by feeding garlic, sarpagandha and nicotinic acid. Haryana Agric. Univ. J. Res., 9: 263-265.
Shoetan, A., K.T. Augusti and P.K. Joseph, 1984.
Hypolipidemic effects of garlic oil in rats fed ethanol and a high lipid diet. Experimenta, 40: 261-263.CrossRef | Direct Link |
Silagy, C. and A. Neil, 1994.
Garlic as a Lipid-Lowering Agent. In: A Meta-Analysis, Coll, J.R. (Ed.). Physicians, London, pp: 39-45
Sklan, D., Y.N. Burner and H.D. Rabinowitch, 1992.
The effect of dietary onion and garlic on hepatic lipid concentrations and activity of antioxidative enzymes in chicks. J. Nutr. Biochem., 3: 322-325.Direct Link |
Steel, R.G.D. and J.H. Torrie, 1982.
Principles and Procedures of Statistics. 1st Edn., McGraw Hill, New York, USA
Warshafsky, S., R.S. Kamer and S.L. Sivak, 1993.
Effect of garlic on total serum cholesterol. A meta-analysis. Ann. Int. Med., 119: 599-605.PubMed | Direct Link |
Yeh Suhni, H., L. Tai jui Jane, S. Luoh Yea, C. Huang Sheng, L. Chang Hsui and C. Tai, 1996.
Blood profile of native chicken in Taiwan. J. Taiwan Livestock Res., 29: 257-263.