Biochar litter amendment concerning environmental health and immunity in broilers

Environmental hygiene is an important factor in poultry production to keep broiler chickens’ health and welfare. This study aimed to evaluate biochar-amended poultry litter to enhance environmental hygiene and broiler chickens’ health and immunity by reducing bacterial load and improving environmental quality. For 5 consecutive weeks, a total of 60 one-day-old Cobb broiler chickens were divided into three groups: a control group (CN) reared on sawdust litter, and two treated groups where sawdust litter was amended with 10% biochar (10%BC) and 20% biochar (20%BC) groups. BC was produced from poultry litter of the CN group through pyrolysis at 450 °C. Total bacterial count, as well as Escherichia coli and Salmonella count in the air and litter environments, were weekly increased in the CN group. Biochar treatment, especially with the 10%BC group, significantly reduced bacterial counts. Hematological analysis revealed an elevated white blood cell (WBCs) count and a reduced heterophils/lymphocytes (H/L) ratio in the biochar-treated groups, indicating enhanced immune status and reduced stress compared to the CN group. Flow cytometry indicated significant increases in peripheral blood CD4 and CD8 T-lymphocytes, particularly with the 10%BC group. Serum immunoglobulins (IgA, IgY, IgM) were also released significantly with BC groups, especially 10% BC, compared to the CN group. Histopathological alterations in the spleen and thymus gland of broiler chicken biochar groups revealed structural improvements compared with the CN group. These findings suggested that biochar addition to poultry litter optimally enhances environmental hygiene, immune function, and overall broiler health, especially with 10%BC concentration. Thus, biochar represents a promising litter management strategy to mitigate bacterial load and improve poultry welfare.