Dietary arginine silicate inositol supplementation supports egg quality and bone metabolism in late phase laying hens

Dietary Arginine Silicate Inositol (ASI) was investigated as a nutritional intervention to enhance performance, egg characteristics, and bone quality of hens in late lay through mechanisms related to calcium metabolism. Lohmann LSL-Lite laying hens (7 hens/cage) were randomized into 5 dietary treatments: control, 0.025 %, 0.05 %, 0.10 %, or 0.15 % ASI with 10 cage replicates for a 16-wk trial separated into 2 phases, 65 to 75 wk (phase 5) and 76 to 81 wk (phase 6). Hens were weighed monthly, and feed intake, egg characteristics, and additional production parameters were recorded weekly and compiled by phase and overall. Blood and fecal samples were collected once monthly for calcium metabolism analysis (1 hen/cage; and 24 h total fecal collection/cage via pan, respectively). A subset of hens and excised tibia were scanned by dual-energy x-ray absorptiometry at baseline and study conclusion. ASI supplementation did not affect weight, feed intake, feed conversion ratio, or egg production in phase 5, phase 6, or overall (P > 0.05). Feeding 0.05 % ASI improved eggshell strength in phase 5 and overall compared to all treatments (P < 0.05). Dietary ASI supplementation of 0.10 and 0.15 % increased the bone mineral content (BMC) vs control at wk 81 (P < 0.05). Calcium excretion linearly decreased with increasing ASI levels at 69 wk (excreta; P < 0.05), while phosphorus excretion was unaffected. Excreta trace minerals, including iron, manganese, and zinc, decreased linearly with higher dietary ASI levels at 81 wk of age (P < 0.05). Overall, dietary ASI supplementation supported egg quality and bone metabolism in a dose-dependent manner in aged hens, likely by improving mineral retention and calcium bioavailability during the late-laying cycle.