ABSTRACT This study aims to identify relative proportions of beneficial and pathogenic bacteria in the gut of broilers and risk factors that may be contributing to the development of colibacillosis disease in broiler farms of District Kasur, Punjab, Pakistan. For this, 10 healthy and 10 colibacillosis affected broiler farms were surveyed for ileum and blood sample collection along with data regarding farm management, antibiotic use and hygiene practices. Lactobacillus and Escherichia coli number was estimated using Miles and Misra method and colibacillosis was confirmed by Congo red dye assay. Lactobacillus and E. coli were identified biochemically. For risk factors analysis chi-square analysis was performed to find any significant association between the health status of the farm and risk factors. Results showed during disease and healthy conditions Lactobacillus and Escherichia coli counts differ significantly (p<0.05). E. coli counts (106-108 to 107-109) increased (p<0.05) about three folds and Lactobacillus counts decrease (106-108 to 105-107) about four folds in disease conditions. Risk factor analysis showed colibacillosis disease was significantly associated (p<0.05) with non-vaccinated flocks, natural ventilation systems, rodent presence and the lack of outfit disinfection or change by workers when moving between different houses. It is concluded that E. coli and Lactobacillus work antagonistically to each other. However, further research is necessary to determine the exact mechanisms by which E. coli and Lactobacillus influence the development of colibacillosis. While Lactobacillus as probiotic may help with prevention, good hygiene and management practices are still crucial in preventing the spread of disease.

This study was designed to investigate the effects of a probiotic plus an immunomodulatory product on the growth performance, immune response and net economic returns of broiler chicks vaccinated against Infectious bursal diseases virus (IBDV). A flock of 350 day-old chicks were equally and randomly distributed in seven groups, each comprising 50 birds. A mixture of microorganisms (¹Probiotic) or Cyclophosphamide (immune suppressor) was offered through feed supplementation to different groups. The Probiotic, consisting of Lactobacillus species, Bifidobacterium, Streptococcus salivarius and Enterococcus faecium, in addition to Aspergillus oryza and Candida pintolopessii. Compared with control treatment group, the probiotic-supplemented chicks had better feed conversion ratio (FCR) (1.938 and 1.959), with significantly heavier live body weight 2141.0±34.2 and 2120.3±33.2, respectively. Similarly, their antibody titers against IBDV were significantly higher (941 and 832) on day 35. No morbidity and mortality were observed in these groups. This study suggests that a product composed of a probiotic and cyclophosphamide enhanced the growth rate as well as the immunity against infectious bursal disease virus of broilers chicks.