the present invention uses a dietary composition for dogs which contains garlic in an amount of between about 1 to 10 g / kg diet . such a diet provides sufficient garlic to provide antioxidant , anticancer , and immunomodulatory effects . a preferred garlic for use in the present invention is a premium garlic powder which is commercially available from gilroy foods . this form of garlic is preferably comprised of dehydrated garlic prepared from fresh pungent varieties of allium sativum which has been cleaned , sliced , dehydrated and milled to powder . however , it should be appreciated that other forms of garlic which provide the desired antioxidant , anticancer , and immunomodulatory effects may also be used . the dietary composition may be in the form of any suitable dog food formula which also provides adequate nutrition for the animal . for example , a typical canine diet for use in the present invention may contain about 20 - 40 % crude protein , about 4 - 30 % fat , and about 1 - 11 % total dietary fiber on a dry matter basis . however , no specific ratios or percentages of these or other nutrients are required . the garlic may be blended with such a dietary composition to provide the beneficial amounts needed . alternatively , the garlic may be provided in the form of a dietary supplement . an experiment was conducted to study the potential beneficial effects of garlic on the immune response of dogs . 28 beagle dogs ( age range : 2 - 4 years ) were fed a basal control diet for 30 days . dogs were then randomized by body weight and divided into 2 groups . within each group , half the dogs continued to receive the control diet and the other half were switched onto the garlic diet . this experimental period was conducted over a 77 - day period . blood was taken at the end of the baseline period ( t 1 — day 0 of the experimental period ), in the middle of the experimental period ( t 2 — day 35 ) and at the end of the study ( t 3 — day 77 ) in order to determine in vitro immune function ( by lymphocyte blastogenesis ) as well as cytokine production ( tumor necrosis factor ; tnf - α ), interleukin - 1 ( il - 1 ), and il - 6 . urine was collected at these time points and immediately frozen in order to analyze for various markers of oxidative stress . in vivo immune function was determined by a delayed - type hypersensitivity ( dth ) response test using a nonspecific antigen ( phytohemagglutinin ), a specific mitogen ( duramune ® vaccine [ fort dodge laboratories ]), and control ( saline ) to induce an inflammatory response and induration was measured at 24 , 48 , and 72 hours postinjection with data expressed as measurements corrected for saline . dogs were weighed weekly and fed to maintain body weight throughout the study . water was provided ad libitum . see table 1 for the ingredients and composition of diets . isolation of mononuclear cells . blood collected in heparinized tubes was diluted in calcium - and magnesium - free hanks balanced salt solution ( hbss ) ( 1 : 1 ), layered onto ficoll - hypaque , and centrifuged at approximately 400 × g for 20 minutes . the mononuclear cells were harvested , washed in hbss , and resuspended in rpmi - 1640 growth medium containing 5 mg / ml bovine serum albumin ( bsa ), 100 u / ml penicillin , 100 μg / ml streptomycin , and 1 % l - glutamine . cells were counted in a coulter counter ( coulter corporation , hialeah , fla . ), and 1 × 10 6 cells in 7 ml of medium were plated in 60 mm well plates and allowed to adhere for 2 - 3 hours in a humidified co 2 incubator at 37 ° c . the nonadherent cells were removed by gentle washing with medium , and the isolated monocytes incubated with growth medium plus 10 μg / ml of o55 : b5 eschericia coli lipopolysaccharide for 24 hours . the culture supernatant fluid was harvested , and the adherent cells digested with 1n ammonium hydroxide and 0 . 2 % triton x - 100 for total cellular dna quantitation . cytokine assays . bioassays for il - 1 , tnf - like activity , and il - 6 were performed as previously described . mouse plasmacytoma cell line ( t1165 . 17 ), which proliferates in response to il - 1 and il - 6 , was used to assay for il - 1 activity . to determine specific il - 1 activity , the il - 1 receptor on the t1165 . 17 cell line was blocked using a monoclonal antibody ( la 15 . 6 ) to the il - 1 receptor . murine fibroblasts ( l929 ) were used to assay for tnf - like activity and the il - 6 bioassay was performed using b9 cells . data from the bioassays were expressed as pg of cytokine per μg of monocyte dna . lymphocyte blastogenesis . mononuclear cells from the blood were isolated as described above via centrifugation on ficoll - hypaque . after washing in hbss cells were resuspended in culture medium containing 10 % heat inactivated fetal calf serum , 100 u / ml penicillin , 100 μg / ml streptomycin , and 1 % l - glutamine and adjusted to a final concentration of 1 × 10 6 cells / ml . concanavalin a ( con a ) was added to 3 wells of a 96 - well plate for each sample and 200 μl of the mononuclear cell suspension added . the final concentration of con a in each well was 10 μg / ml . the culture plates were incubated at 37 ° c . in a cell culture incubator for 72 hours , and then each well was pulsed with 1 μci of [ 3 h ] thymidine ( 50 μl volume ) and incubated an additional 24 hours . cells were harvested on glass fiber filters ( phd cell harvester ), and the amount of [ 3 h ] thymidine incorporation determined ( decays per minute ; dpm ) in a scintillation counter . cytokine production . there was no significant difference between the control - and garlic - fed animals for any of the cytokines measured . there was also no significant change in the garlic - fed animals compared to baseline values ( t 1 ), although there was a slight trend ( not significant ) for reduced tnf and il - 6 with garlic feeding ( fig1 ). lymphocyte blastogenesis . there was no significant difference between the control - and garlic - fed group in lymphocyte proliferative response to the mitogen con a . however , in the garlic - fed group there was a significant linear trend ( p = 0 . 0003 ) for increased lymphocyte blastogenesis from t 1 ( baseline ) to t 3 ( 77 days ). moreover , lymphocyte blastogenesis was significantly increased ( p & lt ; 0 . 05 ) at t 3 ( 77 days ) compared to the initial baseline values at t 1 ( fig2 ). delayed - type hypersensitivity . there were no significant differences between the dietary groups in delayed - type hypersensitivity ( dth ) response . at the midpoint of the study ( 35 days ), there was some indication of a trend ( not significant ) for increased hypersensitivity to duramune vaccine in the garlic - fed group , but this trend was not maintained and there was no evidence of a garlic effect on dth by the end of the study . garlic powder had no effect on cytokine production from canine peripheral blood mononuclear cells or on dth response . however , the garlic - fed dogs had significantly enhanced lymphocyte blastogenesis compared to their baseline values . the results demonstrate that garlic can function as an immunomodulatory agent . garlic demonstrated an immunomodulatory effect with respect to mitogen - induced lymphocyte blastogenesis . while certain representative embodiments and details have been shown for purposes of illustrating the invention , it will be apparent to those skilled in the art that various changes in the methods and apparatus disclosed herein may be made without departing from the scope of the invention , which is defined in the appended claims .
a composition and method for enhancing immune response and improving the overall health of canines is provided which includes feeding the canines a dietary composition containing an effective amount of garlic in an amount of from about 1 to 10 g / kg diet . the dietary composition , when fed to canines , provides antioxidant , anticancer , and immunomodulatory benefits . the canines are fed the composition containing an effective amount of garlic in a quantity and frequency appropriate for their nutritional needs resulting in an enhanced immune response by increased lymphocyte blastogenesis and improves the overall health of the animal .