| dc.description.abstract | Two studies were designed to evaluate the growth promoting and prebiotic properties of Yeast Cell Wall (YCW) containing mannanoligosaccharides (MOS) and guar gum galactomannans in starting broilers. In study one, the effects of different sources and concentrations of YCW-MOS and a blend from both the sources were investigated in starting broilers under both challenged (immune stress and Clostridium perfringens challenge) and unchallenged conditions through a series of 6 challenged and 4 unchallenged experiments. Weekly body weights, feed consumption, and daily mortality were recorded. Each experiment was terminated after 3 weeks. YCW-MOS had no effect in the unchallenged birds. Pooled data analysis of challenged broilers revealed no effect of source of YCW-MOS. Both the products tested produced significant improvement in growth rate compare to the control birds. However, the blend of YCW-MOS showed approximately 15% improvement in growth rate with 10% reduction in feed conversion rate (FCR). The optimum dose of tested YCW-MOS products in starting broilers is determined to be 250 ppm. YCW-MOS additives produced increased body weight with a reduction in FCR and may be considered as alternatives to antibiotic growth promoters.
In study two, newly hatched broiler chicks (24 pens, 6 replicates per treatment) were randomly distributed among four dietary treatments to evaluate the effects of guar gum galactomannans (GG) with and without Mannanase Guar® enzyme in starting broilers. Effects of dietary treatments (negative control, positive control-YCW product Safmannan (YCW-S) at 500 ppm, GG at 500 ppm and GG at 500 ppm with enzyme (GGE) on growth, FCR, apparent ileal energy digestibility (AIED), intestinal histomorphology and microbial ecology were investigated. No significant differences were observed in body weight, feed conversion, mortality and productivity index. GG diets produced significantly reduced AIED, villus height, and increased crypt depth compared to the control. Broilers receiving GGE had overall intestinal villus height and AIED equal to YCW-S. Microbial patterns from the YCW-S and GGE treated broilers grouped together with a 95.6% similarity coefficient suggesting near identical microbial populations between these two groups. GG may have potential to consider as a prebiotic in starting broilers when used with an appropriate exogenous enzyme. | en |
