Bifidobacteria in Broiler Starter Rations: Factors Affecting Survival

The viability of freeze-dried cells of bifidobacteria (B. thermophilum ATCC 25525) in broiler starter rations was monitored at different storage temperatures during a twelve-week period. A total of five treatments (control plus four bifidogenic factors), at low (1.55% moisture, aw< 0.4) and high water activity (10.52% moisture, aw = 0.64) were included in the study. Results indicated that lower moisture and water activity enhances the survival of bifidobacteria when incorporated into feeds. Refrigeration temperatures (5•Ž and 18•Ž) also increase the survival of bifidobacteria in rations stored for up to twelve weeks. Bifidogenic factors, when included in the feeds, had a limited protective effect on bacterial survival. The use of probiotics, containing bifidobacteria, is an area that needs to be closely evaluated before they can be added to animal rations under commercial condi-