Effects of modified corn straw supplementation on laying performance, egg quality, immune response, antioxidant capacity, lipid metabolism and intestinal microbiota of post-peak laying hens.

Corn straw is potential dietary fiber-rich resources, which can be used as functional feed after appropriate modification. This research investigated the impact of modified corn straw (MCS) on production performance, egg quality, immune responses, antioxidant capacity, lipid metabolism, intestinal morphology and microbiota of post-peak laying hens. 225 Hy-Line brown laying hens aged 50-wk were divided into three groups: basal diet, basal diet added with 0.5 % MCS and basal diet added with 1.5 % MCS. The experiment lasted 56 d. The results showed that compared to control group, the average egg production in 0.5 % MCS group was increased by 11.48 % during 1-28 d and 14.47 % during 29-56 d (P<0.05). 0.5 % and 1.5 % MCS increased albumen height and haugh unit of eggs, serum levels of IgA, IgG, IgM and SOD, hepatic levels of GSH-PX, as well as villus height and villus height to crypt depth ratio of jejunum and ileum (P<0.05), while concurrently reducing hepatic MDA levels (P<0.05). 0.5 % MCS addition decreased serum levels of LDL-C, TG and TC, hepatic levels of fat, TC, TG, fat droplets and fat vacuoles, as well as the abdominal fat index (P<0.05), while simultaneously increasing serum HDL-C levels (P<0.05). Furthermore, 0.5 % MCS addition increased Firmicutes, unclassified_f__Lachnospiraceae, Ruminococcus_torques_group and Christensenellaceae_R-7_group (P<0.05), while decreasing Bacteroidota and Spirochaetota (P<0.05). These microorganisms regulates lipid metabolism. In conclusion, adding 0.5 % MCS to post-peak laying hens' diet increased the laying performance, egg quality, humaoral immune response and antioxidant capacity, reduced liver steatosis and fat deposition, and improved the intestinal health.