Effect of intensity and duration of quantitative feed restriction on broiler caecum microbiota

Abstract

This study evaluated the effects of quantitative feed restriction with different intensity and duration on broiler intestinal microbial flora. Using a completely randomized design, Ross 308 male broiler chicks (115; 3 replications/ treatment; 10 chicks/replication) were assigned to 5 experimental treatments. These included quantitative feed limitations in 50% (T2,T3) and 25% (T4,T5) lower than the recommended by the Ross 308 broiler catalogue in 2 periods of 7 (T2, T4) and 14 days (T3, T5), with one control treatment (T1; feed intake as ad lib.). All chicks were fed ad lib. before and after the limitation period, until slaughter (day 42). The results showed that quantitative feed restriction had significant effects on microbiota of ceca in broilers except for lactic acid bacteria. A feed restriction of 25% during 7 days (T4) resulted in the highest mean value for coliforms and Escherichia coli; in contrast, a feed restriction of 25% during 14 days (T5) resulted in the highest mean value for lactobacilli and enterobacteria. A feed restriction of 50% during 7 days did not affect microbial count when compared with the control group. The number of total bacteria was higher in T4 although the difference had not been statistically significant from T2 and T3. Major alterations occurred for E. coli and coliforms in T4, lactobacilli and enterobacteriaceae in T5 and enterecoccus in both T3 and T4. It is concluded that a feed restriction of 25% during 7 days (T4) gave rise to the growth of other species than those analyzed in this study whereas a feed restriction of 25% during 14 days increased lactobacilli and enterobacteriaceae.