Dried Chlorella powder supplementation: Impact on broiler chicken growth, health, and intestinal microflora

The use of dried Chlorella as an immune and growth stimulant to enhance nonspecific host defense mechanisms or as an antimicrobial to inhibit bacterial growth has been reported. This study aimed to assess the effects of dried Chlorella powder (DCP) supplementation on the growth, health, and intestinal microflora of commercial broiler chicks, comparing a diet containing DCP with an antibiotic-based diet. A total of 120 pieces day-old Cobb 500 broiler chicks were reared at Sher-e-Bangla Agricultural University Poultry Farm, Dhaka, and randomly divided into four experimental groups of three replicates each, with 10 chicks per replication. One group was fed a control diet, while the remaining three groups were fed diets with 0.5% and 1.0% DCP, and antibiotics, respectively. Results indicated significant (P<0.05) improvements in body weight and dressing percentage with DCP inclusion compared to control-fed broilers. A linear increase in body weight was observed with higher DCP levels, with birds on the 1% DCP diet achieving superior body weights (1665.13±8.82) compared to the control and antibiotic groups. Feed Conversion Ratio (FCR) and feed consumption were also significantly (P<0.05) improved, with the best FCR at 1% DCP (1.37±0.01) and the highest FCR in the control group (1.45±0.00). The highest feed consumption was noted in the control group. No significant (P>0.05) differences were observed in the relative weight of spleen and bursa among the groups. DCP had no significant (P>0.05) effects on liver, gizzard, intestine, and heart weights. Hematological studies revealed no significant (P>0.05) differences, except for Hemoglobin and Red Blood Cells (RBC), which were significantly (P<0.05) increased by DCP compared to control and antibiotic groups. DCP supplementation significantly (P<0.05) reduced E. coli and Salmonella sp. counts while increasing Lactobacillus sp. counts. Additionally, treatments with DCP significantly (P<0.05) boosted Newcastle disease (ND) titre levels compared to the control group. The study showed that DCP can be effectively replaced antibiotics in broiler diets, enhancing growth, health, and immune response, thereby promoting sustainable and safer poultry production practices.