Hemp seed is a potential candidate to replace soybean meal dependency due to its rich protein and balanced amino acid profile content despite containing anti-nutrients. This study purposed to evaluate dietary heated hemp seed cake (HSC) and the addition of phytase as a substitution for soybean meal on broiler productive performances, carcass characteristics, visceral organ weight, serum biochemical and intestinal health of broiler chickens. A total of 210 unsexed Ross broiler chicks were randomly divided into 7 treatments and 6 replicates using a completely randomized design and reared for 42 days. The treatments were T1: Corn-soybean-based ration; T2: Ration containing 15% unheated HSC; T3:T2 + 1000 FTU of phytase; T4: Ration containing 15% autoclaved HSC (120 °C,10 min); T5: T4 + 1000 FTU of phytase; T6: Ration containing 15% oven-heated HSC (120 °C,20 min); T7: T6 + 1000 FTU of phytase.

On day 42, the body weight and body weight gain of the T4 group were higher (P < 0.01) compared to the T2, T3, T6, and T7 groups. The relative length of the jejunum, ileum, and cecum in all HSC diets was higher than that of the T1 group (P < 0.01). Dietary T4 lowered total bacteria and E. coli and enhanced L. acidophilus population in the cecum (P < 0.01). The villus height and surface area in all HSC diets were lower than those in the T1 group (P < 0.01). Glucose and calcium levels in the T4 and T5 groups were higher than those in the T1, T2, and T3 groups (P < 0.01). It concluded that dietary autoclaved HSC has positive effects on the gut health and growth of broiler chickens compared to dietary oven-heated HSC and unheated HSC. However, the positive effects cannot match those of soybean meal and corn-based diets.