DETERMINATION OF TITANIUM-DIOXIDE ADDED AS AN INERT MARKER IN CHICKENDIGESTIBILITY STUDIES

A method was developed to determine the concentration of titanium diox ide in poultry digesta samples, obtained from the lower half of the sm all intestine of three-week-old male broiler chickens. Titanium dioxid e was added at a rate of 5 g kg(-1) as a dietary marker, Only 0.1 g of freeze-dried digesta sample was required. The sample was ashed and di ssolved in 7.4 M sulphuric acid. Hydrogen peroxide (30% vol.) was subs equently added, resulting in the typical orange colour the intensity o f which was dependent upon the titanium concentration. Aliquots of the solutions obtained and of similarly prepared standard solutions were analysed using a UV spectrophotometer and measuring the absorbance at 410 nm. Validation of the method showed that: 1. Prepared samples coul d be kept for at least 48 h before measuring on the spectrophotometer. 2. Titanium dioxide recovery was not significantly affected by ashing or filtering of the sample during preparation. 3. Other components in the digesta sample did not affect absorbance. 4. Accurate and reprodu cible results were obtained when using the chicken digesta samples. It was concluded that the method was suitable in the quantitative determ ination of titanium dioxide concentration in chicken digesta samples o btained during digestibility studies.