Effects of feeding restriction and meal pattern of a sugar beet-containing diet and control diet on nutrient digestibility, plasma lipid concentrations and postprandial triacylglycerol response in broiler chickens.

Broiler chickens were fed on a control diet based on maize or a diet containing sugar-beet-pulp fibre (Beetfiber) at an inclusion level of 46 g/kg. Diets were provided ad lib. or at a restricted level either once daily or three times daily. On days 13 and 20, chickens fed on the ad lib. control and sugar-beet-pulp-containing diets generally weighed more and had poorer feed conversion ratios than chickens given the restricted control and sugar-beet-pulp-containing diets respectively. Furthermore, chickens given the restricted diets once daily had greater body weights and generally improved feed conversion efficiencies compared with chickens given the restricted diets three times daily. Generally, elevated plasma lipid concentrations were observed amongst chickens given the restricted diets once daily compared with chickens fed ad lib. as well as the restricted diets three times daily, while chickens fed on restricted diets three times daily had plasma lipid concentrations intermediate between those fed ad lib. and once daily. In a plasma triacyglycerol response study on day 22, feeding of sugar-beet-pulp-containing diets generally reduced postprandial triacylglycerol concentrations and delayed triacylglycerol response relative to chickens given the control diets either ad lib. or restricted, which may indicate gastrointestinal adaptation to feeding of a fibre-rich diet. Postprandial triacylglycerol concentrations observed for chickens receiving restricted diets were increased compared with chickens given the respective ad lib. diets, indicating adaptation of chickens to reduced feed frequency. On day 25, feeding of sugar-beet-pulp-containing diets decreased digesta dry matter content and ileal organic matter digestibility. Chickens given sugar-beet-pulp-containing diets generally had, on day 25, increased caecal short-chain fatty acid (SCFA) concentrations in comparison with chickens given the ad lib. control diet, indicating increased fermentation of dietary components. It is also noteworthy that the greatest SCFA concentrations were observed amongst chickens given the control diet once daily, suggesting enhanced caecal fermentation capacity. This may have been a consequence of increased bacterial activity and caecal hypertrophy due to infrequent feeding of a low-fibre diet.