Research Note: Effects of glycerol monolaurate supplementation on egg production, biochemical indices, and gut microbiota of broiler breeders at the late stage of production

The objective of the present study was to determine the effect of glycerol monolaurate (GML) supplementation on egg production, biochemical indices, and gut microbiota of broiler breeders at the late stage of production. Total of 180 healthy Qingyuan Partridge broiler breeders were randomly assigned to 2 groups: 1) corn-soybean meal based diet, and 2) basal diet supplemented with 300 mg glycerol monolaurate/kg. Each treatment group had 6 replicates with 15 birds within each replicate. The experiment started at wk 33 and lasted for 8 weeks. Feed conversion rate, egg weight, egg shape index, shell breaking strength, and shell thickness were not different between control and treatment groups. Supplementation of GML significantly decreased the egg breaking rate. All blood chemical indices and antioxidant parameters were not affected by GML except total antioxidant capacity which increased significantly with GML supplementation. Alpha diversity indices (Shannon, Simpson, Chao1, Ace, goods_coverage, and PD_whole tree) were not different between the 2 groups. Composition of cecal microbiota was not affected by GML supplementation except Euryarchaeota and Proteobacteria at phylum level. Overall, supplementation of glycerol monolaurate at 300 mg/kg level improved eggshell quality but its effect on cecal microbiota composition was limited on broiler breeders at the late stage of production.