Evaluation of Mineral Composition, Physical Properties, and Nutritional Value of Local Rock Flours as Feed Supplements for Laying Quails

The province of West Sumatra is rich in natural rock deposits that could serve as alternative mineral sources in poultry diets. This study evaluated the mineral composition, physical properties, and nutritional value of rock flour from four areas: Padang Panjang (PP), Palupuh (PH), Halaban (HB), and Kamang (KG). Rock flour samples (50 kg each) were analyzed for macro- and trace minerals, particle size distribution, bulk density, and angle of repose. Their nutritional potential was tested by supplementing 2.5– 9.0% rock flour in iso-nitrogenous, iso-caloric, and iso-calcium diets for 200 laying quails (Coturnix coturnix japonica), allocated into five dietary treatments: basal diet + 2.5% oyster shell (control, P0), + 9% PP (P1), + 7% PH (P2), + 6% HB (P3), and + 2.5% KG (P4), with 4 replicates of 10 birds each. Calcium content varied widely (5.08–39.74%), with KG containing the highest level (p<0.01). Rock flours were also rich in Fe (643–3611 ppm), Mn (29.6–320.3 ppm), and Zn (2.50–14.02 ppm). Bulk density ranged from 1.12–1.58 g/mL, and fine particles (<250 μm) dominated (52–88%). Dietary treatments had positive effects on egg production, feed conversion ratio (FCR), and eggshell quality. Kamang rock flour (P4) achieved the highest egg production (333.5 ± 8.6 g/bird/day), heaviest eggshells (0.78 ± 0.03 g), and the lowest FCR (3.42 ± 0.11), while maintaining tibia bone weight (0.84 ± 0.02 g) comparable to the control. These results indicate that locally sourced Kamang rock flour is a viable alternative to oyster shells for improving production performance and bone mineralization in laying quails.