Faculty of Animal Science & Veterinary Medicine

STUDY ON ISOLATION, CHARACTERIZATION AND IDENTIFICATION OF LACTIC ACID BACTERIA DERIVED FROM FERMENTED DAIRY PRODUCTS

2026-02-08T09:46:07Z

STUDY ON ISOLATION, CHARACTERIZATION AND IDENTIFICATION OF LACTIC ACID BACTERIA DERIVED FROM FERMENTED DAIRY PRODUCTS RAHMAN, ABDUR Lactic acid bacteria (LAB) are important in dairy food fermentation which have beneficial health properties. The research was conducted to isolate, characterize and identify the LAB derived from fermented dairy products like dahi, borhani, matha, lassi, cheese and to assess their antibiotic susceptibility patterns. The bacteria were isolated based on their colony morphology on de Man, Rogosa, and Sharpe (MRS) agar and selected based on gram-staining properties, biochemical properties and molecular tests. Salt tolerance, sugar fermentation and growth at different temperatures and salt concentrations were observed for all isolates. PCR followed by 16S rDNA sequencing was done to identify the bacteria. All isolates survived at low (≤5%) NaCl concentration, but could not tolerate high (≥6%) NaCl concentration. All isolates can ferment glucose, sucrose, and lactose. All the tested isolates were sensitive to antibiotics like gentamicin, ciprofloxacin, tetracycline and ceftriaxone. Finally, the identified bacterial species were Lactobacillus rhamnosus from dahi, lassi and matha samples and Lactobacillus fermentum was identified from the cheese sample which are known as probiotic species. Ultimately, the research revealed two antibiotic-sensitive LAB species suitable for incorporation into fermented dairy product formulations. A thesis Submitted to the Department of Dairy Science Faculty of Animal Science and Veterinary Medicine Sher-e-Bangla Agricultural University, Dhaka in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN DAIRY SCIENCE

CHARACTERIZATION AND ANTIBIOGRAM STUDY OF SOME PATHOGENIC BACTERIA ISOLATED FROM FERMENTED DAIRY PRODUCTS IN DHAKA CITY

2025-06-19T07:01:38Z

CHARACTERIZATION AND ANTIBIOGRAM STUDY OF SOME PATHOGENIC BACTERIA ISOLATED FROM FERMENTED DAIRY PRODUCTS IN DHAKA CITY SULTANA, MST. TASMIM This study aimed to investigate the microbiological quality of various fermented dairy products by isolating different pathogenic bacteria and antibiogram study. A total of 50 samples consisting packaged (n=30) and non-packaged (n=20) were aseptically collected and subjected to microbiological analysis. The samples were cultured on selective media to isolate and identify pathogenic bacteria based on morphological, biochemical, microscopic and molecular characteristics and finally antibiogram study was done for the isolated bacteria. From the study, it was found that the dahi had the highest titratable acidity, with mean values of 1.003%, while lassi, matha, and burhani had lower mean values of 0.51%, 0.63%, and 0.65%, respectively. The Total Viable Count (TVC) of all fermented dairy products ranged from 6 to 8 log CFU/ml, with the mean Total Coliform Count (TCC) being lowest in packaged dahi and highest in nonpackaged burhani. Furthermore, the Total Salmonella-Shigella Count (TSS) and Total Staphylococcal Count (TSC) is remarkable in non-packaged burhani and non-packaged dahi. Out of the 50 samples in total, 52% contained Escherichia coli, 10% had Staphylococcus, and 4% showed the presence of Salmonella species. In the current research, it was discovered that 52% of the samples contained at least one type of bacteria from three different genera: Staphylococcus, Escherichia coli, and Salmonella. The overall prevalence rate was lower in packaged products (30%) than non-packaged (85%) products. Almost all of the isolated bacteria were resistant to amoxicillin, tetracycline and erythromycin exhibiting less resistance pattern to ciprofloxacin, gentamicin and neomycin. This study revealed that in spite of having high acidity, fermented dairy products sold at different markets in Dhaka city were contaminated with multiple species of antibiotic resistant bacteria. Keywords: Characterization, pathogenic bacteria, fermentation, antibiogram, dairy products, A Thesis Submitted to the Department of Dairy Science Sher-e-Bangla Agricultural University, Dhaka in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN DAIRY SCIENCE

PREVALENCE OF CANINE TICK-BORNE PROTOZOA ASSOCIATED WITH HEMATOLOGY IN DHAKA CITY

2024-02-04T04:40:53Z

PREVALENCE OF CANINE TICK-BORNE PROTOZOA ASSOCIATED WITH HEMATOLOGY IN DHAKA CITY KHATUN, MOST. AKLIMA Dogs, being companion animals serve a variety of economic, social, and cultural purposes. Among the diseases of dogs, tick-borne protozoa are drawing attention globally for both human and animals. The aim of this study was to observe the prevalence of tick-borne protozoan infections as well as some selective hematological parameters of stray dogs in Dhaka city. A total number of 160 dogs from various places in the study area were selected randomly and examined for both tick and protozoan infection. Only one species of hard tick, Rhipicephalus sanguineus was identified where 49 (30.62%) among the study population were found to be infested with this tick. There were differences in tick burdens in two seasons with higher infestation levels in Summer (37.50%) followed by Winter (26.92%). Ticks ranging from 1-16 were removed from dogs where most of the ticks were collected from the neck and chest region (P <0.001). On the other hand, examinations of blood smear confirmed three protozoan species (Babesia canis, Babesia gibsoni, and Hepatozoon spp.) comprising 23.13% of the overall prevalence. Among the protozoan species, B. canis (11.88%) was the most prevalent protozoa. Subsequently, only 10.81% of the infected samples showed multiple infections. In both cases, females were more infected than males. Among the hematological parameters, the RBC counts, Hemoglobin, and PCV of all infected dogs were significantly lower (P <0.001) compared to the healthy group. Moreover, the eosinophil of the infected groups showed higher values (11.00 % and 12.70% for protozoa and ticks, respectively) than the normal range indicating parasitic infections. Therefore, these results suggest the necessity of frequent blood examinations to enhance animals’ welfare and disease prevention. A Thesis Submitted to the Department of Microbiology and Parasitology, Sher-e-Bangla Agricultural University, Dhaka-1207, in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE (MS) IN PARASITOLOGY

EFFECTS OF BACTERIOPHAGE SUPPLEMENTED DIET ON INTESTINAL BENEFICIARY MICROFLORA AND PRODUCTIVE PERFORMANCE OF BROILER

2024-01-28T10:17:42Z

EFFECTS OF BACTERIOPHAGE SUPPLEMENTED DIET ON INTESTINAL BENEFICIARY MICROFLORA AND PRODUCTIVE PERFORMANCE OF BROILER NAIN, MD.ZULKAR The Experiment was done to investigate the effects of dietary bacteriophage (BP) supplementation on production performance and status of microflora in excreta along with carcass characteristics in broilers. A total of 600 day old broiler chicks were reared randomly allotted in 5 treatment groups having 4 replications R 1, R 2, R 3 and R .Where each replication contain 30 birds for 5 weeks at SAU Poultry Farm, Dhaka-1207.These dietary treatments were designed as T 0 (Control diet), T (Control+ 0.5g Bacteriophage per kg feed),T 2 (Control+ 0.75g Bacteriophage per kg feed ) ,T 1 (Control+1g Bacteriophage per kg feed) and T 4 3 ( Control+ANT 0.05g per Kg Feed). In broilers the inclusion of antibiotic and bacteriophages directly affect the feed intake (P= 0.002) among the five groups.BWG (Body Weight Gain) in T group was higher(2209.00 ±16.45 gm) which showed significant differences (P<0.05) among the other groups. LW (Live weight), FC( Feed Consumption) and FCR(Feed Conversion Ratio) at the end of 5 1 th week were significant (P< 0.05) in different group, however better BWG, LW, FC were found in treated group T where BWG, LW and FC were 2209.00 ±16.45 gm , 2251.00±16.45 gm & 3069.00±22.70 gm respectively. Whereas FCR performance was positively correlated with the levels of bacteriophage given in the diet. Highest FCR (1.39 ± 0.02) found in T treatment. However, there are insignificant effect found in survivability (P >0.05) at 35 days of age of broiler .Bacteriophage group showed significant results in case of liver ,spleen, heart & breast weight compared to control and antibiotic except the gizzard weight . Results demonstrated that the average ammonia level was same at the end of the 1 week , however it varied significantly (P<0.05) at the 3 rd & 4 th weeks of age (10.10±0.57 ppm & 13.75 ± 1.02 ppm). But at the end of 5 th week T 2 & T group showed highest ammonia emissions (18.50± 0.65 ppm & 18.25± 0.85 ppm respectively). Ammonia emissions were found lowest in T 1 3 (13.25±1.38 ppm).Flock uniformity demonstrated significant differences between the control and T Group (67.72± 4.27 %.).The lactobacillus was significantly (P<0.05) lower in antibiotic and control group rather than the bacteriophage supplemented diet . T 1 1 showed highest lactobacillus (3.97 ± 0.13 CFU/ml) and T showed the lowest (0.43± 0.07 CFU/ml). In conclusion, it can be said that , bacteriophage supplementation has beneficial effects on production performance of broiler and it can expand the beneficiary microbes in guts of commercial broiler chicken. A Thesis Submitted to the Department of Poultry Science Sher-e-Bangla Agricultural University, Dhaka In Partial fulfillment of the requirements for the degree of MASTER OF SCIENCE (MS) IN POULTRY SCIENCE