An experiment was conducted with 240, 1-d-old, male broilers to investigate the effects of Saccharomyces cerevisiae (SC) cell components on the growth performance, meat quality, and ileal mucosa development. There were 4 dietary treatments, each consisting of 6 replicates. Whole yeast (WY), SC extract (YE), and SC cell wall (CW) were added at 0.5, 0.3, and 0.3%, respectively, to the control starter and finisher diets. From 0 to 3 wk of age, a lower feed/gain ratio (P < or = 0.05) was observed with CW, whereas the WY-fed birds at 4 to 5 wk of age showed a lower feed/gain ratio compared with the control. From 0 to 5 wk of age, WY and CW gave higher BW gains than did the control. The shear force of raw drumstick decreased in the WY treatment relative to the control, and YE and CW treatments were intermediate. The shear forces in cooked breast and drumstick in treatments WY and YE decreased when compared with the control. The amount of 2-thiobarbituric acid-reactive substances (TBARS) in the breast meats of WY, YE, and CW were lower than the control at 10 d of incubation. In raw drumstick meats, TBARS values were lower in treatments WY and YE than that of the control at 6 and 10 d of incubation. At 10 d of incubation, skins from YE and CW treatments had lower TBARS values than did the control. Villus height was greater in WY and CW compared with those in control and YE. No differences were found in crypt depth among the 4 treatments. The villus height/ crypt depth ratios in WY and CW were greater than those of the control and YE. It could be concluded that dietary yeast components, such as WY or CW supplementation improved growth performance. Meat tenderness could be improved by the WY or YE. Both YE and CW had oxidation-reducing effects. Yeast cell wall may improve ileal villus development.

Inorganic phosphate (Pi) is present in bacteria, fungus, plant, and animal cells. Pi plays a critical role in mineral metabolism, and diverse cellular functions involving intermediary metabolism and energy transfer. It is a vital component of membrane phospholipids, nucleotides that provide energy, DNA and RNA, and is necessary for phosphorylated intermediates in cellular signaling (1).Bronchial epithelial cells, the progenitor cells for bronchogenic carcinomas, are often exposed to diverse xenobiotics, including toxicants. Many investigators elucidated the precise mechanisms of pulmonary toxicant-induced normal bronchial epithelial cell damage. The response of bronchial epithelium to chemical and physical injury has been associated with the induction of hyperplasia and the subsequent development of squamous metaplasia (2). The modified response of nontumorigenic bronchial epithelial cells to external/internal stimuli causes a disturbance in the homeostasis between normal cell survival and growth. Therefore, the elucidation of such disturbed homeo-