Red seaweed Chondracanthus chamissoi supplementation improved the growth performance of broiler chickens partially through effects on intestinal morphology and cecal microbiota

Marine macroalgae has the potential to improve growth performance in broiler chickens due to the presence of bioactive compounds. This study examined the effects of a red seaweed (SW) powder, from Chondracanthus chamissoi, on the growth performance, intestinal morphology, and cecal microbiota of broiler chickens. A total of 256 male Cobb-500 broiler chicks were housed in battery cages and allocated on d 0 post hatching to 4 diets for 21 days in a randomized complete block design consisting of 8 replicate cages and 8 birds per replicate. The 4 diets included a corn-soybean-based diet (basal diet), or the basal diet supplemented with 0.5 %, 1 %, or 1.5 % SW. Body weight (BW) and feed intake (FI) were recorded weekly. On d 7, 14, and 21 post hatching, SW diets linearly increased the BW gain of birds (P < 0.01), but the gain-to-feed ratio (G: F) was not affected by the treatments except from day 0 to 7 (P < 0.05). Dietary SW linearly increased the feed intake throughout the experiment (P < 0.05). Dietary SW increased (P < 0.05) the ileal villus height to crypt depth ratio (VH: CD) and showed a tendency (P = 0.08) to linearly increase ileal villus height (VH). Additionally, dietary SW increased both jejunal VH and the VH: CD ratio (P < 0.05). No differences were observed in alpha diversity metrics; however, beta diversity analysis showed variations in the composition of the microbial community. Differential abundance showed that Bifidobacterium, and Butyricicoccus were abundant taxa in the SW diets. In conclusion, graded inclusions of SW improved the growth performance of broiler chickens when fed for 21 days, by altering the intestinal morphology and microbiota. However, the nutrient digestibility was not improved by seaweed.