INFLUENCE OF METHOD UPON THE DETERMINATION OF APPARENT DIGESTIBILITY IN THE PIG

Abstract

Three experiments were conducted, the first to determine the effects of adding celite to the diets to increase the HCl insoluble ash level, the second to compare a "grab" method of collecting samples with that of total collection, and the third to study the effects that time of sample collection would have on the mean digestible energy (DE) and digestible nitrogen (DN) coefficients. It was found that the addition of celite to the diets of pigs weighing either 5.6 or 22.4 kg did not alter the DE or DN coefficients as compared with coefficients obtained by the total fecal collection method. Both with and without the addition of celite, total fecal collection gave DE and DN coefficients which were higher than those obtained by the HCl insoluble ash method, but the difference was significant only in one of the three experiments. There was no significant difference between "grab" samples and total collection methods, indicating that the former could be used in place of total collection. Over a 72-h period, no differences associated with diurnal variation were noted in DE and DN coefficients as determined by the HCl insoluble ash method. This indicates that the time of collecting samples should not influence DE and DN values.