The synchronized absorption of amino acids and glucose in the gut is essential for amino acid utilization and protein synthesis in the body. The study aimed to investigate how the starch digestion rate and amino acid levels impact the growth and intestinal starch and amino acid digestion, transport, and metabolism in juvenile broilers. The experiment was conducted with 702 Arbor Acres Plus broilers at 1 d old, which were randomly divided into 9 treatments with 6 replicates of 13 chickens each. The treatments included 3 different starch sources (corn, waxy corn, and tapioca) with 3 different apparent ileal digestible lysine (AID Lys) levels (1.08%, 1.20%, and 1.32%). A notable interaction was noted for dietary starch sources and AID Lys levels in the feed-to-gain ratio (F/G) and distal ileal starch digestibility (P < 0.01). The tapioca starch and waxy corn starch diets with 1.32% of AID Lys significantly decreased F/G compared with corn starch (P < 0.01). There was no significant difference in F/G of broilers among waxy corn starch diet with 1.08% AID Lys level, tapioca starch diet with 1.20% AID Lys level, and corn starch diet with 1.32% AID Lys level (P > 0.05). The 1.32% AID Lys level and the waxy corn starch both improved the body weight (BW) of broilers from 0 to 3 weeks of age, intestinal starch digestibility, and intestinal villi height or the ratio of villi height to crypt depth (P < 0.05). Compared with the corn starch diet, waxy corn starch and tapioca starch diets significantly elevated the AID of Met, Glu, Lys, Arg, Asp, His, Ile, Tyr, Gly, and Val levels (P < 0.05). The carbon metabolomics results revealed that the waxy corn starch diet significantly reduced malic acid and cis-aconitic acid levels (P < 0.05) in the tricarboxylic acid cycle compared to the corn starch diet. It was concluded that a waxy corn starch diet improves the growth performance of broilers by improving intestinal morphology, increasing the absorption and transport of amino acids, reducing the amino acid oxidation for energy supply in the intestinal mucosa, and promoting protein synthesis in muscles, which not only reduces the need for dietary AID Lys but also saves on production costs.

This study investigated the effects of digestible lysine (dLys) in different dietary starch sources on liver lipid metabolism and breast muscle protein metabolism in broiler chickens. The experimental design was a 3 × 3 two-factor completely randomized design. A total of 702 one-day-old male Arbor Acres Plus broilers were randomly divided into nine treatments of six replicate cages with thirteen birds each. The treatments consisted of three different starch sources (corn, cassava and waxy corn) with three different dLys levels (1.08%, 1.20% and 1.32%). The trial lasted from 1 to 21 days. Carcass traits, serum metabolites, breast muscle protein and liver lipid metabolism were evaluated. A significant interaction effect (p < 0.05) for dietary starch sources and dLys levels was noted in the percentage of abdominal fat and gene expression related to breast muscle protein metabolism throughout the experimental period. The waxy corn starch diet and a 1.08% dLys level in the diet increased both the percentage of abdominal fat (p < 0.01) and blood total cholesterol (p < 0.05) in the broilers. The waxy corn starch diet significantly upregulated the mRNA expressions of Eif4E, AMPK, FABP1, ACC and CPT1 (p < 0.05). The 1.32% dLys level significantly upregulated the mRNA expressions of mTOR, S6K1, Eif4E, AMPK and PPARα (p < 0.05) and significantly downregulated the mRNA expressions of MuRF and Atrogin-1 (p < 0.05). In summary, the waxy corn starch diet resulted in significantly higher expression levels of fat-synthesis-related genes than lipolysis-related genes, leading to abdominal fat deposition in broilers. Increasing the level of dLys in the diet increased the protein content in muscle by promoting protein synthesis and inhibiting protein degradation and also promoted the expression of lipolysis-related genes, thereby degrading the generation of abdominal fat in broilers. Our findings signify that increasing the dLys level to 1.32% when using the waxy corn starch diet could improve carcass traits.

This study was conducted to investigate the impact of EGCG on antioxidant stress, immune response, and intestinal microbiota flora in post-weaning rabbits. A total of 144 40 d Ira rabbits (equally divided by sex), were randomly allocated to six treatments. with five groups receiving doses of 200, 400, 600, 800, and 1000 mg/kg of EGCG, while one group served as a control without EGCG. Over 48 days, this study the assessed growth performance, antioxidant capacity, immune system, intestinal morphology, and cecal microbiota in the rabbits. The results showed that EGCG did not affect growth performance; however, significant linear and quadratic correlations were observed between the MDA, T-AOC, and GSH-Px activities in the liver and jejunum (p < 0.05). Quadratic effects were observed for the spleen and thymus indexes and serum IgG levels with increasing EGCG dosages (p < 0.05). Additionally, positive linear and quadratic effects were found on the ileal villus height and the villus height/crypt depth ratio. The relative abundances of Euryarchaeota, Patescibacteria, and Synergistota were significantly enriched in rabbits fed with high dosages (600–1000 mg/kg) of EGCG. Conclusively, the addition of large doses of EGCG (400–800 mg/kg) can effectively suppress oxidative stress and alleviate weaning stress, thereby contributing to the protection of post-weaning rabbits.

This study evaluated the effects of dietary starch characteristics on intestinal energy metabolism and microbial profiles in Epigallocatechin gallate (EGCG)-supplemented broiler chickens. A total of 300 Arbor Acres male broilers were assigned to five dietary treatments consisting of a corn–soybean basal diet (NC), EGCG supplementation (500 mg/kg) (PC), or diets in which 20% corn was substituted with purified corn (CS), cassava (TS), or pea starch (PS) in the presence of EGCG (500 mg/kg). Growth performance, starch digestion, intestinal energy status, cecal microbiota, and metabolomic profiles were evaluated. The results showed that broilers fed the corn starch-containing diet under EGCG supplementation showed improved average daily gain and feed conversion ratio (p < 0.05). This treatment also increased intestinal ATP and cAMP concentrations while reducing AMP and the AMP/ATP ratio, accompanied by enhanced activities of Na⁺-K⁺-ATPase, citrate synthase, and pyruvate dehydrogenase. Cecal microbiota analysis showed that Lactobacillus abundance was increased in the CS group, whereas Barnesiella was enriched in the PS group. Differential metabolites associated with energy metabolism, including lipoic acid, palmitoylcarnitine, and crotonic acid, were significantly changed among treatments. In conclusion, dietary starch characteristics influenced intestinal energy metabolism-related indicators, microbial profiles, and metabolite patterns in broilers receiving EGCG supplementation.