Effect of replacement of shell grit with stone grit on egg quality characteristics in Namakkal Gold Quail

Premkumar, K., Kannan1, D., Vasanthakumar, P. , Rajendran, K., Ramakrishnan, S. and Kannan, V. 2025. Effect of replacement of shell grit with stone grit on egg quality characteristics in Namakkal Gold Quail. Indian Journal of Poultry Science, 60(1): 19-28. A study was undertaken to evaluate the feasibility of using stone grit as an alternative calcium source in egg type Japanese quail diet. A biological trial was conducted by using 360 numbers of five week old female “TANUVAS Namakkal Gold quail” strain developed for egg production, divided into five dietary treatment groups, by replacing shell grit with 2 mm or 4 mm stone grit at 50 or 100 per cent levels in the diet. The study was conducted for 52 weeks, monitoring egg quality and calcium content in eggshell for every 28 days period. Both external and internal quality of the eggs was ascertained from 8 to 52 weeks of age, totally seven periods at 8, 12, 20, 28, 36, 44 and 52 weeks of age. Five eggs having the average egg weight without any shell defects from each replicate were selected for egg quality analysis. Partial (50 per cent) replacement with 2 mm stone grit resulted in significantly heavier eggs at 36 (P<0.05) and 52 (P<0.01) weeks of age, compared to control and other groups. Albumen quality (albumen index and Haugh unit) was significantly lower (P<0.01) in both 50 per cent replacement groups at 8, 28 and 36 weeks. Yolk quality (yolk index) was lower (P<0.01) in the 50 per cent replacement with 2 mm stone grit group at 20, 36, 44 and 52 weeks. Yolk color was significantly reduced (P<0.01) in the 50 per cent replacement with 4 mm stone grit group at 28, 36 and 44 weeks. Eggshell thickness and eggshell weight was significantly higher (P<0.01) in 50 per cent replacement with 2 mm stone grit fed group at 8 and 52 weeks of age. Eggshell calcium content and shape index were unaffected by treatments throughout the study period. However, all egg quality parameters were not significant for the overall study period, suggesting that both 2 mm and 4 mm stone grit can be safely included in the egg type quail ration without compromising the egg quality.