Dietary supplementation with RG92 improves laying performance and egg quality in laying hens

The productive lifespan of commercial laying hens has been extended through genetic improvement; however, age-associated declines in egg production and egg quality remain major challenges for the poultry industry. This study evaluated the long-term effects of supplementation with the microalga Mucidosphaerium sp. RG92 on laying performance and egg quality in laying hens. In an experimental trial, Boris Brown laying hens were maintained as one control flock (10 hens) and one RG92-supplemented flock (10 hens) from 5 to 119 weeks of age. To assess whether a similar pattern was observed under practical commercial farming conditions, a separate field evaluation was conducted using one control flock (309 hens) and one RG92-supplemented flock (289 hens) from 47 to 79 weeks of age. During the experimental trial, the RG92-supplemented flock showed a less pronounced age-associated decline in hen-day egg production, lower proportions of broken and oversized eggs, and a higher proportion of acceptable eggs during the late laying period. Under commercial farming conditions, eggs sampled from the RG92-supplemented flock showed higher albumen height, Haugh unit, and yolk index. To investigate physiological and molecular responses associated with RG92 supplementation, fecal short-chain fatty acid (SCFA) concentrations and peripheral blood mononuclear cell (PBMC) transcriptomic profiles were evaluated. RG92 supplementation was associated with higher fecal concentrations of acetate, propionate, and butyrate. RNA sequencing of PBMCs revealed transcriptomic differences associated with immune regulation and cellular redox homeostasis. Collectively, these observations suggest that RG92 supplementation may help attenuate age-associated deterioration in laying performance and egg quality during prolonged laying and was accompanied by changes in fecal SCFA profiles and PBMC transcriptomic profiles, supporting further evaluation of RG92 as a functional nutritional strategy for laying hens.