Dose-dependent Role of Natural Betaine on Gut Morphometry, Cecal Microbiota, and EggProduction in Backyard Golden Misri Hens

The study aimed to investigate gut health-based production performance of backyard Golden Misri laying hens upon supplementing natural betaine at 0 (Control), 0.34 (Low betaine), and 0.68g (High betaine) natural betaine/kg body weight.A total of 150 hens (251 weeks) were equally assigned to these groups, with 5 replicates each containing 10 birds.After 7h daily scavenging, birds were offered commercial concentrate and water containing respective betaine doses.Hens in both betaine treatments increased feed intake, and Low betaine improved egg production, egg mass, and eggshell strength relative to Control (P<0.05).The jejunal villus height: crypt depth ratio showed a higher tendency for Low betaine relative to High betaine (P=0.07).By employing 16S rRNA gene sequencing, both betaine treatments indicated a significant increase in microbial alpha diversity parameter Sobs (P=0.02) and a similar trend for Chao1 (P=0.06).The genus Desulfovibrio proliferated at both betaine doses (P=0.04), and Parabacteroides (P=0.02) and Odoribacter (P=0.09)only in the High betaine group in comparison to the Control.Low-dose natural betaine is more suitable for ensuring health of the early gut compartments and production status, while High dose has more pronounced effects in later parts of the gut like ceca.In conclusion, Betaine water containing 0.34g/kg body weight is suggested for backyard hens during captivity.