Effects of dietary supplementation with butyrate glycerides on lipid metabolism, intestinal morphology, and microbiota population in laying hens.

The present study investigated the impact of butyrate glycerides (BG) on lipid metabolism, intestinal morphology, and microbiota of laying hens. Four hundred eighty 54-week-old Hy-line Brown laying hens were randomly selected and divided into five groups. The control group (ND) was fed a basal diet. Meanwhile, the remaining groups were given a basal supplemented with 0.5, 1, 2, and 4 g/kg of the product containing BG and were designated as BG-0.5, BG-1, BG-2, and BG-4 groups, respectively. The findings showed that: (1) BG supplementation significantly decreased (P < 0.001) the blood Glu levels (BG-0.5, BG-1, BG-2, and BG-4) and increased (P < 0.001) the serum HDL-C levels (BG-2, and BG-4). (2) The BG-2 and BG-4 groups showed an increase (P < 0.01) in abdominal lipid HSL activity. (3) The levels of hepatic TC and TG in all BG groups were significantly decreased (P < 0.05). (4) The addition of BG resulted in a significant reduction in the mRNA expression of the liver X receptor alpha (LXRα) (P < 0.05). (5) All BG groups presented a substantial reduction in duodenal crypt depth and a notable increase in the ratio of villus height to crypt depth (V/C) (P < 0.01). Additionally, all BG groups exhibited a significant increase in villus height in the ileum (P < 0.001). (6) Both the BG-1 and BG-4 groups exhibited a significant reduction in the amounts of n-butyric and n-glutaric acids in the cecum contents (P < 0.05). (7) The inclusion of BG did not substantially impact the diversity of cecal microbiota in laying hens. However, it dramatically boosted the proportion of the beneficial bacterium Alistipes (P < 0.05) and reduced the abundance of the harmful bacterium Verrucomicrobiota (P < 0.05). Overall, incorporating BG with glycerol monobutyrate as the diet's primary active component reduces fat accumulation in laying hens' blood and liver. It potentially regulates lipid metabolism via the PPARγ-LXRα-SREBP1c pathway. Additionally, BG has the potential to enhance the structure of the small intestine's mucous membrane and increase the presence of beneficial bacteria. Under the experimental conditions, late-laying hens supplemented with 4 g/kg BG performed best overall.