Growth performance, carcass traits, blood indices, and cecal bacterial load of Koekoek chickens fed diets containing neem leaf meal, bitter leaf meal, and garlic powder

This study evaluated the effects of dietary inclusion with phytogenic feed additives, namely neem leaf ( Azadirachta indica ), bitter leaf ( Vernonia amygdalina ), and garlic powder ( Allium sativum ), on growth performance, carcass traits, haematobiochemical indices, and cecal microbial load in Koekoek chickens. A total of 192 male Koekoek chicks were randomly allocated to four dietary treatments in a completely randomized design (CRD): a basal control diet (T1) and three experimental diets supplemented with neem leaf meal (T2), bitter leaf meal (T3), and garlic powder (T4), each at an inclusion level of 2.5%. The results demonstrated that chickens fed the phytogenic-supplemented diets, particularly the bitter leaf-inclusion diet (T3), exhibited significantly higher ( P < 0.05) average daily body weight gain, feed conversion ratio (FCR), and final body weight than control diet (T1). Carcass trait analysis revealed significant enhancement ( P < 0.05) in slaughter weight, dressing weight, different cut parts, and liver. The haematological analysis indicated a reduction in white blood cell counts in chickens fed the control diet (T1). Serum biochemical analysis revealed significant differences ( P < 0.05) among treatments in total protein, globulin, creatinine, glucose, and high-density lipoprotein levels. Analysis of the cecal microbiota revealed a significant increase ( P < 0.01) in Lactobacillus counts, accompanied by a notable reduction in pathogenic bacteria, including Escherichia coli and Salmonella . Overall, chickens receiving the bitter leaf-inclusion diet (T3) showed the most pronounced improvements in body weight gain and FCR, together with a favorable cecal microbial profile characterized by higher Lactobacillus counts and lower E. coli and Salmonella loads. This finding suggests that bitter leaf supplementation has potential as a dietary strategy for improving growth performance and promoting a favorable gut microbial balance in Koekoek chickens.