As wheat dried distillers’ grains with solubles (WDDGS) become increasingly available in western Canada, there is currently a great interest in evaluating its potential as a feedstuff for pigs. Thus, the apparent, standardized and true ileal crude protein (CP) and amino acid (AA) digestibilities in WDDGS were determined. Six finishing pigs (∼82kg initial BW) fitted with a simple T-cannula at the distal ileum were fed diets containing either 400g/kg WDDGS or 50g/kg casein as the sole protein source in a simple crossover design. Chromic oxide (3g/kg) and acid insoluble ash (AIA, 10g/kg) were included in the diets as indigestible markers. The casein diet was used to quantify endogenous protein and AA losses. Standardized ileal CP and AA digestibilities were estimated using published basal endogenous protein and AA losses. Pigs were acclimatized to their diets for 5 days followed by a continuous 12-h digesta collection period on days 6 and 7. Ileal CP and AA digestibility coefficients obtained with AIA as a marker were similar to those obtained with Cr2O3 (P>0.05). Endogenous losses, coefficient of apparent ileal digestibility and coefficient of true ileal digestibility in g/kg dry matter intake were 22.81, 0.64 and 0.79 for CP, 0.94, 0.73 and 0.89 for arginine, 0.41, 0.68 and 0.79 for histidine, 0.46, 0.73 and 0.81 for isoleucine, 0.59, 0.78 and 0.83 for leucine, 0.54, 0.36 and 0.56 for lysine, 0.10, 0.71 and 0.77 for methionine, 0.32, 0.82 and 0.86 for phenylalanine, 0.89, 0.62 and 0.78 for threonine and 0.59, 0.71 and 0.79 for valine. Of all the essential AA analyzed, lysine had the lowest digestibility value, which suggests reduced availability of this AA.

An in vitro trial was conducted to evaluate the fermentation characteristics of soybean meal oligosaccharides (SMO) and changes in the caecal contents microbial community of broiler chickens as affected by SMO by using cumulative gas production and a PCR/DGGE technique. An in vivo trial aimed to study the effect of SMO on the caecal contents lactic acid bacteria (LAB) population and caecal wall attached microorganisms by means of a real-time PCR technique and scanning electron microscope, when SMO was used in the diet of broiler chickens during the first 2 weeks of post-hatch. In vitro trial results indicated SMO produced 245.7 ml gas/g DM, 261.8 mg acetic acid/g DM, 187.2 mg propionic acid/g DM and 155.2 mg butyric acid/g DM. In vivo experimental results showed that dietary SMO increased visible microbial populations attached on caecal walls and increased the population of a group of lactic acid bacteria (genera of Lactobacillus, Pediococcus, Weissella and Leuconostoc) in the caecal contents of young broiler chickens (P<0.05). In conclusion, SMO does show promise for use as a product which may promote competitive exclusion of potential pathogens. SMO may therefore, be a suitable substitute for dietary antibiotics in young broiler chickens in the future. As a potential prebiotic material, the selective stimulation of SMO on LAB could not be certified by the current experimental results and needs to be further studied.

Fermentable carbohydrates can lead to changes in the gut microflora, which may have positive consequences for health. However, often, ingredients are added to diets without prior investigating about their potential fermentability within the target animal. The experiment reported, was conducted to investigate the fermentation kinetics of some non-digestible carbohydrates (NDC) by the caecal microbial community of broiler chickens by an assessment of the cumulative gas production during fermentation of each substrate. It also aimed to study changes in the microbial community, following fermentation of these non-digestible carbohydrates, by use of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Four extracted non-digestible carbohydrates (ENC): soybean meal oligo- and water-soluble polysaccharides (SMO and SMP), alfalfa meal oligo- and water-soluble polysaccharides (AMO and AMP) were studied. Two pure sugars, raffinose (RAF) and stachyose (STA) were also included. To assess the fermentability of the substrates, cumulative gas pressure was monitored continuously, for 72 h, and at the end of fermentation, pH, volatile fatty acid (VFA), and ammonia (NH3) concentrations were measured in the fermentation solution. The PCR-DGGE technique was applied to compare microbial DNA fingerprints between substrates at the end of the fermentation. The inoculum for the in vitro gas production was obtained from a mixture of caecal contents of forty 81-day-old broiler birds. Soy oligosaccharides led to significantly more butyric acid production (P<0.05) after fermentation compared with other ENC. The production of butyric acid was 155.2 mg/g DM, 100.3 mg/g DM, 84.5 mg/g DM and 71.8 mg/g DM for SMO, SMP, AMP and AMO, respectively. Soy oligosaccharides had the lowest pH (5.5) and ammonia–nitrogen concentration (199.3 mg/l) after fermentation. This was significantly different from other ENC and the pure sugars. DGGE analysis revealed that, the fingerprint of caecal bacterial communities showed some variation (C, value >60–80%) between some of the substrates. It was concluded that SMO, SMP, AMO and AMP, as well as RAF and STA were significantly different, both in terms of their fermentation kinetics and end-products using caecal contents from adult broilers. The extent to which these non-digestible, but fermentable, carbohydrates could change the microbial community of the broiler caecum, either in terms of the species detected, or its activity, needs to be investigated further, and then related to its effect on gut health in the animal itself.

To understand the relationship between the gastrointestinal inhabiting microbial community and broiler health, a literature review is presented. The available information on the development of gut microbial community, the relationship between commensal microflora and digestive function, the role of gut microorganisms on competitive exclusion of chickens against pathogens, and modulation of the gut microbial community by addition of prebiotics to the diet is summarized. Gut dominant microbial communities become more complex as broilers grow older. The establishment of the dominant bacterial community is affected by dietary and host-related factors. Dietary prebiotics can modulate bacterial community shift towards non-harmful bacteria, which is beneficial for the health of broiler chickens. Gut commensal microorganisms play an important role in the prevention of colonization by pathogens in the gastrointestinal tract of chickens, a process known as competitive exclusion. In conclusion, the dilemma caused by the forthcoming ban of antibiotics feed additives and need to maintain the intestinal health of broiler chickens, has produced an enormous interest in finding alternatives. Modulating the intestinal microbial community in a healthy direction, by dietary ingredients such as prebiotics, could be a good solution.

This experiment was conducted to test whether dietary soybean meal oligosaccharides (SMO) and water-soluble polysaccharides (SMP) can assist broiler chickens in resisting Eimeria tenella, and to determine the survival of lactic acid bacteria in cecal contents postinfection. All birds received a soybean meal-free diet. The 6 experimental treatments were as follows: positive (COR) and negative (COW) control groups, 2 groups fed diets containing either 1% SMO or 0.5% SMP from 1 to 11 d of age; a vaccinated group (VAC), and an anticoccidial medicated group (ANT). Chickens of all treatments except COW were orally infected with 1000 sporulated oocysts of E. tenella on d 15. Fecal oocyst shedding was monitored per treatment group between d 5 and 13 postinfection. Lactic acid bacteria (LAB) in cecal contents were evaluated by a real-time PCR technique on d 7 postinfection. The results showed that the SMO and SMP groups had a lower number of oocysts per gram of feces during the monitoring period than the COR group. Threshold cycles were 22.21, 27.68, 13.99, 14.92, 12.97, and 14.85, for COW, COR, SMO, SMP, VAC, and ANT groups, respectively; specific PCR products were confirmed by the results of melting curve analysis and agarose gel electrophoresis. The results suggest that these LAB communities were promoted by SMO and SMP and have a competitive exclusion function when broiler chickens are infected with E. tenella.