Neutralizing mineral salts with various acids can be used to give some idea of mineral availability, and when an assay is monitored over time then information on rate of solubility is also obtained. Hopefully, all mineral sources will be totally available to the bird, although, at least with calcium sources, there is concern about solubility. Slow solubilization is preferable to very rapid solubilization, because the former more closely matches the prolonged duration of need for calcium supply to the shell gland in laying hens.
Limestone solubility can easily be measured by monitoring pH of the mineral in dilute acid. After recording the original pH of a 90 ml aliquot of 0.1 N HCl, 10 g of limestone is gradually added, and without stirring, pH measured after time intervals of say 10, 20, 30 and 60 minutes. Limestone will result in an increase in pH, as H+ ions are liberated from solution. A pH change of +0.1 relates to a 20% solubility, while changes of 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1.0 relate to about 37, 50, 60, 70, 75, 80, 84, 87 and 90% solubility respectively. A pH change of +2.0 means 99% solubility. A high solubility after 60 minutes is expected from a quality limestone, whereas the rate of achieving 95 - 99% solubility will give an indication of the rate of calcium release in the proventriculus. Particle size and particle porosity are the factors most likely to affect rate of change of solubility. Optimum eggshell quality, and perhaps bone development in young birds, are dependent upon a consistent pattern of calcium solubility.
Neutralization of ammonium citrate has been used to assess solubility of phosphate sources and also of manganese and zinc salts.
Was this article helpful?
The first trimester is very important for the mother and the baby. For most women it is common to find out about their pregnancy after they have missed their menstrual cycle. Since, not all women note their menstrual cycle and dates of intercourse, it may cause slight confusion about the exact date of conception. That is why most women find out that they are pregnant only after one month of pregnancy.