High amylose to amylopectin ratios in nitrogen-free diets decrease the ileal endogenous amino acid losses of broiler chickens

• Published in: Animal Nutrition Vol. 14; no. 3; pp. 111 - 120
• Main Authors: Zhou, Huajin, Mahmood, Tahir, Wu, Wei, Chen, Yanhong, Yu, Yao, Yuan, Jianmin
• Format: Journal Article
• Language: English
• Published: China Elsevier B.V 01.09.2023; State Key Laboratory of Animal Nutrition,College of Animal Science and Technology,China Agricultural University,Beijing 100193,China%Adisseo Animal Nutrition,DMCC,Dubai 00000,United Arab Emirates; KeAi Publishing; KeAi Communications Co., Ltd
• Subjects: alpha-glucosidase; Amylopectin; Amylose; animal nutrition; blood serum; Broiler chicken; corn starch; diet; digestibility; digestible carbohydrates; Endogenous amino acid losses; Firmicutes; glucagon; Goblet cells; homeostasis; ileum; intestinal microorganisms; malnutrition; Nitrogen-free diet; Original; physiological state; Proteobacteria; species richness; thyroxine; villi; Nitrogen-free diet; Broiler chicken; Amylose; Goblet cells; Amylopectin; Endogenous amino acid losses
• ISSN: 2405-6545; 2405-6383; 2405-6383
• DOI: 10.1016/j.aninu.2023.03.011

This study explored the variation of ileal endogenous amino acid (IEAA) losses and its influencing factors in chickens offered nitrogen-free diets (NFD) containing different ratios of amylose to amylopectin (AM/AP). A total of 252 broiler chickens at 28 d old were randomly allocated into 7 treatment groups for a 3-d trial. The dietary treatments included a basal diet (control), a NFD containing corn starch (CS), and 5 NFD with AM/AP ratios of 0.20, 0.40, 0.60, 0.80, and 1.00, respectively. As the AM/AP ratio increased, the IEAA losses of all AAs, starch digestibility and maltase activity linearly decreased (P < 0.05), but the DM digestibility linearly and quadratically decreased (P < 0.05). Compared with the control, the NFD increased the number of goblet cells and its regulatory genes mucin-2 and krüppel-like factor 4 (KLF-4) while decreasing serum glucagon and thyroxine concentrations, ileal villus height, and crypt depth (P < 0.05). Additionally, NFD with lower AM/AP ratios (0.20 and 0.40) decreased the ileal microbiota species richness (P < 0.05). In all NFD groups, the number of Proteobacteria increased whereas the abundance of Firmicutes dropped (P < 0.05). However, the broilers in the AM/AP 0.60 group were closer to the digestive physiological state of chickens fed the control diet, with no significant change in maltase activity and mucin-2 expression (P < 0.05). In conclusion, increasing AM/AP ratio in a NFD decreased the IEAA losses and the apparent ileal digestibility of starch but inevitably resulted in malnutrition and disruption of gut microbiota homeostasis. This study recommends AM/AP in NFD at 0.60 to measure IEAA of broiler chickens.