The effects of potential dietary prebiotics and grain particle size on the growth performance and intestinal microflora of young poultry

Experiments were conducted to evaluate the effects of grain particle size and several potential prebiotic feed additives when fed for varying lengths of time on growth performance, nutrient utilization, and select cecal and ileal microbial populations in young chicks. In addition, some of these dietary additives were also evaluated for their ability to ameliorate the negative effects of an Eimeria acervulina coccidiosis infection on the above response variables. In the first study, large particle corn, whole sorghum, and Grobiotic (GB) were evaluated in a cornsoybean meal diet with or without the addition of distillers dried grains with solubles (DDGS). In general, the results showed that larger particle sizes from large ground corn or whole sorghum, as well as the addition of GB, can be supplemented to a corn-SBM or corn-SBM DDGS diet with no adverse effect on growth performance and nutrient digestibility when fed from 0 to 21 d of age. Also, relative gizzard weights can be significantly increased (P < 0.05) when large ground corn, whole sorghum, or DDGS is included in young chick diets. The second study evaluated the effects of fine or large ground corn, whole sorghum, or whole wheat in the presence or absence of an acute E. acervulina infection in chicks fed a corn-soybean meal diet. The results of this study indicated that feeding large ground corn, whole wheat, or whole sorghum in the presence or absence of a coccidial challenge significantly increased (P < 0.05) relative gizzard weights and decreased E. coli populations, but had no consistent effects on overall growth performance or responses to E. acervulina infection. The next study evaluated the effects of short-term feeding (3, 7, or 21 d) of GB, Dairylac-80, and lactose in both a corn-soybean meal diet and a casein-dextrose diet, as well as the effects of these additives in the presence or absence of an acute E. acervulina infection. The results of this study indicated that an E. acervulina infection reduced chick performance, MEn, and AA digestibility (P < 0.05), and the addition of GB, Dairylac-80, and lactose were not effective in alleviating the negative effects of a coccidiosis infection. In the absence of a coccidiosis infection, the results indicated that the feeding of GB, Dairylac-80, and lactose may yield some beneficial responses in chick growth performance, especially when added to a casein-dextrose diet; however, the responses were not consistent. Also, short-term feeding of various potential prebiotics, especially those which contain some lactose, can beneficially influence cecal microbial populations in young chicks, particularly elevated levels of bifidobacteria and lactobacilli and decreased levels of E. coli, even when given to the chick for a period of only 3 or 7 d. The final study evaluated the prebiotic potential and the effects of short-term feeding (3, 7, or 21 d) of Elusieve fiber (higher fiber fraction obtained from DDGS), Temulose products (high mannan by-products from the lumber industry), and Alternan (oligosaccharides produced from alternansucrase catalysis) in a corn-soybean meal and caseindextrose diet. Temulose and partially hydrolyzed Temulose had no consistent effects on weight gain, feed intake, or feed efficiency over all time periods. The addition of partially hydrolyzed Temulose for 3 d did increase populations of bifidobacteria and lactobacilli (P < 0.10) when compared to the original, nonhydrolyzed Temulose; however, at 7 d both compounds decreased lactobacilli populations. Diets containing Elusieve fiber and Alternan also had no consistent effects on growth performance when added to a corn-soybean meal diet or casein-dextrose diet. Bifidobacteria were decreased (P < 0.10) when 2% Alternan was added to both types of diets. Overall, this study also indicated that short-term feeding of various potential prebiotics can beneficially influence cecal microbial populations in young chicks even when given for a period of only 3 or 7 d.