Comparison of In Vitro Fermentation and Molecular Microbial Profiles of High-Fiber Feed Substrates Incubated with Chicken Cecal Inocula

Abstract

High fiber and nonstarch polysaccharide-based poultry diets have received more interest recently for retaining or promoting beneficial gastrointestinal microbial populations. The objective of this study was to investigate and compare the in vitro potential fermentability of high-fiber feed substrates (HFFS) by laying hen cecal microflora. Feed sources examined included soybean meal, soybean hull, beet pulp, wheat middlings, ground sorghum, cottonseed meal, 100% alfalfa meal, 90% alfalfa + 10% commercial layer ration, 80% alfalfa + 20% commercial layer ration, and 70% alfalfa + 30% commercial layer ration. Cecal contents and HFFS were incubated anaerobically in serum tubes at 39 degrees C for 24 h. Samples from 2 trials were analyzed at 0 and 24 h for short-chain fatty acids (SCFA). Short-chain fatty acids in samples at 0 h were subtracted from 24-h samples to determine the net production of SCFA. In both trials involving HFFS incubations with cecal inocula, acetate production was highest followed by propionate and butyrate whereas isobutyrate and isovalerate production were in trace amounts. In trial 2, detectable valerate production appeared to consistently occur with alfalfa-based HFFS. It was clear that SCFA production was largely dependent upon HFFS, because cecal inoculum alone yielded little or no detectable SCFA production. For HFFS incubations without cecal inocula, acetate production was highest; propionate and butyrate were similar, and isobutyrate, valerate, and isovalerate production were in trace amounts. Polymerase chain reaction-based denaturing gradient gel electrophoresis results from both trials indicated 69 and 71% similarity for comparison of all feed mixtures in trials 1 and 2, respectively. All alfalfa-based HFFS yielded a higher similarity coefficient in trial 2 than in trial 1 with a band pattern of 90% similarity; diets containing 90% alfalfa + 10% commercial layer ration and 80% alfalfa + 20% commercial layer ration in trial 2 formed a subgroup with a 94% microbial similarity coefficient. These data suggest that high fiber sources may contribute to the fermentation and microbial diversity that occurs in the ceca of laying hens.

Comparison of Nonlinear Models Describing Growth Curves of Broiler Chickens Fed on Different Levels of Corn Bran

“…They reported that adding raw fiber sources had no effect on average daily feed intake from day 1 to day 21 of the age, but it improved the average daily weight gain and feed conversion ratio (FCR). Adding fiber to the diet improves bowel function and development of the digestive system, increases the production of hydrochloric acid (HCl), bile acids and secretion of digestive juices [37], changes the composition and gastrointestinal tract micro flora population of poultry and pig laboratory conditions [38] and breeding conditions [39][40][41]. So, the positive effects of adding fiber on growth performance of broiler chickens is related to the improvement of the digestibility of nutrients and metabolic pathways changes [42].…”

Salmonella Pathogenicity and Host Adaptation in Chicken-Associated Serovars

“…Ricke hypothesized that the key to limiting S. Enteritidis during molt was to develop low-nutrient dietary strategies, such as formulations with high fiber content, that would still induce molt due to low energy density but were sufficiently fermentable to support an active GIT microflora that would serve as a barrier to pathogen establishment (255). Several molt diets with fermentable substrate combinations have been screened in vitro and shown to support optimal avian cecal fermentation (396)(397)(398) and retain similar cecal microbial molecular profiles (397). In vivo application of some of these diets was shown to retain fermentation and GIT populations during molt while limiting the ability of S. Enteritidis to colonize the GIT and become invasive (255,270,392,399,400).…”

HSV (Herpes Simplex Virus)

“…It's interesting to note that these treatments correspond to the highest levels of crude fiber and differed by the fiber's quality (raw material profiles). This is in agreement with previous study which showed that fiber's quality (in diet with high levels of fiber) influence bacterial profile (Dunkley et al, 2007). Moreover, Green (1988) postulated that intestinal bacteria may be responsible of degradation of some non-cellulose fraction of the crude fibers in broilers.…”