Abstract:
Antibiotics are used to fight against bacterial infection and bacterial resistance to
antibiotic are increasing. Hence, this study was conducted to find out the efficacy of
probiotics Bacillus subtilis (BS) and Bacillus licheniformis (BL) on performance and
antimicrobial activity of broiler chicken. One-Day old of cobb-500 broiler chicks
(n=150) were divided into 5 experimental groups with 3 replicates as 10 chicks in
each replication. One of the 5 experimental group fed diet without probiotic was as
control and the remaining four groups fed diet with 4 levels of commercial probiotics
were T
1
(20g BS/metric ton feed), T
2
(50g BS/metric ton feed), T
(20g BL/metric ton
feed) and T
4
(50g BL/metric ton feed). The group T
4
3
treated with 50g BL/ metric ton
feed (MT) showed higher body weight (1607.50±30.98g) compared to control
(1472.14±38.51). Feed consumption was significantly (P<0.05) higher in control
group than probiotic treated groups. FCR was better in all probiotic treated groups
compared to the control (1.52±0.04) and the best feed conversion ratio (FCR) result
was found in T
group (1.33±0.02). Carcass percentage was significantly (P<0.05)
higher in T
4
4
group (71.33±1.30) compared with the control (65.67±1.33). The weight
of breast, thigh, drumstick and giblet was significantly (P<0.05) high in T
group as
compared to others treatment groups and control (T
). In addition, the present study
showed that feeding dietary probiotics in different groups had no significant effect
(P>0.05) on relative weight of neck, wing, intestine, gizzard, spleen and bursa. The
numbers of intestinal microflora (E. coli and Salmonella) were significantly higher
(P<0.05) in control group compared to other groups and among the treatment groups
the number of salmonella bacteria was significantly lower (P<0.05) in T
0
group. Total
expenditure per bird was significantly higher (P<0.05) in treated group (T
) than
control group (T
0
). Feed cost was significantly higher (P<0.05) in control group (T
)
compared to different treated groups. BCR and profit per bird was significantly higher
(P<0.05) in treatment groups than control (T
0
4
4
) and among the treatment groups T
performed better than others. Overall, between these two probiotics (BS and BL), 50g
BL/MT feed showed better results in terms of improved growth performance with
better FCR, better carcass yield with net economic benefit.
2
0
4
Description:
A Thesis
Submitted to the Faculty of Animal Science & Veterinary Medicine,
Sher-E-Bangla Agricultural University, Dhaka-1207,
in Partial Fulfillment of the Requirements
For the Degree of
MASTER OF SCIENCE (MS)
IN
ANIMAL NUTRITION
SEMESTER: JULY-DECEMBER/2019
