Assessment of In vitro Solubility of Stone Grit-A Major Calcium Source in Poultry Feed

In-vitro solubility estimation experiments were conducted on 156 stone grit samples to analyze the major factors influencing solubility and their strength of correlation by using five different strengths of hydrochloric acid (HCl at 0.1N, 0.2N, 0.3 N, 0.5 N, and 1N), three different volumesofHCl (200mL,100mLand 50mL), two different reaction duration (10 minutes and 30 minutes), two different particle sizes (2mm and 4mm) and two different sample weights (1g and 2g) based on the weight loss method. Solubility data analyzed in multiple linear regression model revealed that the variables such as stone grit size (X1), strength of HCl (X2), volume of HCl (X3), and reaction duration (X4) were statistically significant (P<0.01) and the sample weight (X5) was statistically not significant. The strength of HCl, volume of HCl, and duration were positively correlated, whereas the stone grit size was negatively correlated with solubility. The regression equation (Y= -21.993 – 3.888 X1 + 99.607 X2 + 0.123 X3 + 1.83 X4 + 2.295 X5 + µ) was derived to predict the solubility values for different particle sizes of stone grit easily with known sample weight, HCl volume and strength, and reaction duration. In order to obtain the accurate solubility values of stone grit, the estimation procedure was modified in the existing weight loss method by taking 2 grams of sample to react in 100mL of 0.2N HCl for 10 minutes duration. This modified procedure was ideal and suggested for analyzing the solubility for various particle sizes of stone grits available in the market.