Source of Guava (Psidium guajava) leaf: Guava leaf was collected from different places of Dinajpur district of Bangladesh. The leaves were coarsely powdered after treating by means of physical and chemical processes. Then it was directly mixed with manually prepared diets in 0%, 2.5%, 3.5% and 4.5% doses, accordingly. Treatment of guava leaf as feed samples: At first guava leaf was boiled in water for one hour, boiled in alkaline solution 0.1 N for one hour. Then alkali treated guava leaf was boiled in acid solution 0.1 N for one hour, and autoclaved for 20 minutes at 15 IP pressure. Chemical analysis was conducted on both raw and treated guava leaves. Treated guava leaves were dried at 80°C in an electric oven and grind in hummer mill then samples were taken for determination of chemical composition according to AOAC (1990). Experimental diets: The experimental diets in mash form and drinking water was provided adlibitum. All diets were formulated manually to meet the nutrient requirements of broiler (NRC, 1994) .The chicks were fed starter diet from 1 to 10 days, grower diet from 11-20 days and a finisher diet from 21 to 42 days old broiler. Basically Tables (1, 2 and 3) show the composition and the chemical composition of the starter, grower and finisher rations, respectively. The experimental diets were designed asT1 : control T2 : control+ 2.5% guava leaves as mash form T3 : control+ 3.5% guava leaves as mash form T4 : control + 4.5% guava leaves as mash form.
Experimental design: The experiment was conducted at the open sided poultry shed in Hajee Mohammad Danesh Science and Technology University, Dinajpur. A total 180 day-old broiler chick (Cobb 500) were purchased from CP Bangladesh Ltd. All animal experiments were carried out according to the guidelines of “Cobb 500 Breeder Management Guide”. At first chicks were reared at brooding house to adjust with the environmental condition up to 10 days. After 10 days chicks were randomly assigned to their treatments and was divided into four dietary treatment groups composed of 45 chicks in each; each treatment was composed of three replications with 15 birds in each in a complete randomized design (CRD).
Bird’s management: The birds were housed on floor and routinely managed as any other commercial broiler flock. Heating was provided by a single electric brooder, where the initial temperature was set at 37°C and decreased by 1°C per day to final temperature of 28°C at the end of experiment. Supplementary heating was provided as required by mobile butane gas heaters besides to electricity heater. During brooding period, linear feeder and round plastic drinker were used. After that linear feeder was replaced by round plastic drinker. Feed and fresh water were offered to the bird manually according to the experimental schedule. One round plastic feeder and drinker were provided for seven birds. All birds were vaccinated against Newcastle disease at day one and boostering by day 21. Against Gumboro disease the birds were vaccinated firstly at day seven and boostering at day 14. At very first week Gluco- C was used @ 50g/liter water. Water solublable vitamin Rena WS @ 1g/liter and normal saline also provided for first 3 days of brooding.
Observation of birds: All the birds were examined twice daily for any visible physical changes like restlessness, lordosis, abnormal gait, vices and depression as well as feeding style during study period. The performance trial: During the 42 days of experimental period, growth performance was evaluated. Before treatment, body weight was taken for each group of birds. Then body weight and feed consumption were recorded daily and body gain and feed conversion ratio were then calculated by using the following formula. Mortality was recorded throughout the study period.
Determination of Antimicrobial activity of guava leaf extract Collection of samples: Swaps were taken using sterile swap sticks from the naval of day-old chicks. These were inoculated into the plates containing MacConkey and blood agars. Using the half and quarter plate streaking method, respectively. Culturing and identification of the organisms: The inoculated plates were incubated immediately for 24h at 37°C. The growth was then identified using colonial appearance, gram stain, examination of the organisms under microscopes. Sub-culture was done by using different media for confirmation of the organisms earlier identified. All media used were prepared according to manufacturer’s instructions. Determination of Antimicrobial properties Bacterial isolates: The bacteria were isolated by special media culture; e.g. MacConkey for E. coli. The bacterial isolates from the naval of day-old-chicks were used for determining the anti bacterial properties of guava leaf extract. The isolates were propagated and stored on nutrient agar plates. All the isolates were maintained on nutrient agar plate at 4°C and sub-cultured in nutrient broth at 37°C for 8 hours prior to antimicrobial testing. One milliliter of the broth culture was then used to flood the agar plates. Concentration of extracts: Stock solutions of the extract were prepared by dissolving known weight of the extract in known volume of distilled water 0.01, 0.02 and 0.04g of the extracts were dissolved in 1ml of distilled water to afford 100, 200 and 400mg/ml of the extract, respectively. Standard antibacterial agent oxytetracycline (Renamycin -500mg, renata animal health. Bangladesh) at a concentration of 10mg/ml was also used on all the bacteria and the zones of inhibition compared with those of the plant extract.
Determination of Antimicrobial activity of guava leaf extract Collection of samples: Swaps were taken using sterile swap sticks from the naval of day-old chicks. These were inoculated into the plates containing MacConkey and blood agars. Using the half and quarter plate streaking method, respectively. Culturing and identification of the organisms: The inoculated plates were incubated immediately for 24h at 37°C. The growth was then identified using colonial appearance, gram stain, examination of the organisms under microscopes. Sub-culture was done by using different media for confirmation of the organisms earlier identified. All media used were prepared according to the manufacturer’s instructions. Determination of Antimicrobial properties Bacterial isolates: The bacteria were isolated by special media culture; e.g. MacConkey for E. coli. The bacterial isolates from the naval of day-old-chicks were used for determining the anti bacterial properties of guava leaf extract. The isolates were propagated and stored on nutrient agar plates. All the isolates were maintained on nutrient agar plate at 4°C and sub-cultured in nutrient broth at 37°C for 8 hours prior to antimicrobial testing. One milliliter of the broth culture was then used to flood the agar plates. Concentration of extracts: Stock solutions of the extract were prepared by dissolving known weight of the extract in known volume of distilled water 0.01, 0.02 and 0.04g of the extracts were dissolved in 1ml of distilled water to afford 100, 200 and 400mg/ml of the extract, respectively. Standard antibacterial agent oxytetracycline (Renamycin -500mg, renata animal health. Bangladesh) at a concentration of 10mg/ml was also used on all the bacteria and the zones of inhibition compared with those of the plant extract.
Statistical analyses: Data were analyzed by two factor analysis (diet and strain) of variance using Completely Randomized Design with factorial arrangement of time and treatments (Steel and Torrie, 1986). The significance differences between the treatment means were calculated by the Duncan’s Multiple Range Test. All analyses were performed by MSTATC and SPSS Program.