Assessing the effect of rate and extent of starch digestion on laying hen performance

Effects of supplementing a polyphenol-rich sugarcane extract through drinking water on egg production and quality of laying hens

Polyphenols are a wide group of naturally occurring compounds found in plants and have the potential to safeguard living cells. The objective was to evaluate whether the inclusion of a polyphenol-rich sugarcane extract (PRSE) in drinking water could improve egg production and the quality of commercial layers. A total of 120 Shaver Brown hens, aged 43 weeks, were randomly allocated to 12 litter-floor pens in two open-sided poultry houses. The pens were divided into two treatment groups: one receiving 0% (control) and the other 0.05% PRSE in drinking water throughout the study duration. The treatments were prepared by adding PRSE manually into the drinking water daily, and water was given ad libitum. The birds were given commercial layer feed throughout the study. The number of eggs produced, abnormal eggs, and mortality were recorded daily. Egg weight, yolk colour, yolk height, albumen height, Haugh units, and antioxidant properties, were measured at weeks 45, 47 and 49. Supplementing PRSE in the drinking water did not impact hen-day egg production, hen-housed egg production, egg weight, egg mass, or feed conversion ratio. However, there was a trend toward significance in egg weight at week 45. The results indicated that PRSE supplementation led to a significant reduction in yolk colour during week 45 (P = 0.001), although no differences were observed in subsequent weeks. Yolk height, thick albumen height, and haugh units were unaffected by the treatment, while thin albumen height showed a trend towards reduction in the PRSE group at weeks 47 and 49 (P = 0.05). The DPPH assay revealed a significant increase in antioxidant capacity in the PRSE group at week 45 (P = 0.02). The 0.05% PRSE supplementation in drinking water initially enhanced antioxidant capacity but later adversely affected yolk color and thin albumen height.

Dietary starch structure modulates nitrogen metabolism in laying hens via modifying glucose release rate

The objective of this study was to investigate the effects of starch structure (Amylopectin/Amylose, AP/AM) in a low-protein diet on production performance, nitrogen utilization efficiency, and cecal flora in laying hens. Four hundred eighty 45-wk-age Hy-Line Gray laying hens were randomly allocated to five dietary groups and subjected to a 12-wk feeding trial. The AP/AM ratios of the five experiment diets were 1.0, 1.5, 2.0, 3.0, and 4.0. The results indicated that compared to other groups, laying hens fed with AP/AM 4.0 diets showed significantly improved average egg weight and feed conversion ratio (P < 0.05). Furthermore, as the AP/AM ratio increased, there was a significant linear enhancement in intestinal amino acids apparent digestibility, apparent metabolizable energy, and villus area (P < 0.05). Compared to the high AP groups, high-AM diets significantly increased eggshell thickness, crude protein digestibility, and reduced energy supply from amino acid oxidation in ileum (P < 0.05). Additionally, moderate-AM diets enriched with short-chain fatty acid-producing bacteria in the cecum, such as Lactobacillus, Rikenellaceae_RC9_gut_group, and Christensenellaceae_R-7_group, which are associated with the promoting nitrogen utilization. These findings may offer useful information on optimizing starch structure for the design of food products and relevant therapies due to the potential effects on nutrient metabolism and gut homeostasis.

Assessing the effect of starch digestion characteristics on ileal brake activation in broiler chickens

The objective of this research was to evaluate activation of the ileal brake in broiler chickens using diets containing semi-purified wheat (WS; rapidly and highly digested) and pea (PS; slowly and poorly digested) starch. Diets were formulated to contain six WS:PS ratios (100:0, 80:20, 60:40, 40:60, 20:80, 0:100) and each starch ratio was fed to 236 Ross 308 male broilers housed in 4 litter floor pens. At 28 d of age, the effect of PS concentration was assessed on starch digestion, digestive tract morphology, and digesta pH and short-chain fatty acid (SCFA) concentration. Glucagon-like peptide-1 (GLP-1) and peptide tyrosine-tyrosine (PYY) status were assessed in serum (ELISA) and via gene expression in jejunal and ileal tissue (proglucagon for GLP-1). Data were analyzed using regression analyses, and significance was accepted at P ≤ 0.05. Increasing dietary PS resulted in reduced starch digestibility in the small intestine, but had no effect in the colon. Crop content pH responded quadratically to PS level with an estimated minimum at 55% PS. Total SCFA increased linearly in the crop with PS level, but changed in a quadratic fashion in the ileum (estimated maximum at 62% PS). Ceacal SCFA concentrations were highest for the 80 and 100% PS levels. The relative empty weight (crop, small intestine, colon), length (small intestine) and content (crop jejunum, Ileum) of digestive tract sections increased linearly with increasing PS concentration. Dietary treatment did not affect serum GLP-1 or PYY or small intestine transcript abundance. In conclusion, feeding PS increased the presence of L-cell activators (starch, SCFA) and increased trophic development and content of the digestive tract, suggestive of L-cell activation. However, no direct evidence of ileal brake activation was found by measuring venous blood levels of GLP-1 or PYY or corresponding gene expression in small intestine tissue.