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The capacity for n-3 polyunsaturated fatty acids (PUFA) to improve broiler chicken growth, influence the intestinal microbial communities, and modify the PUFA content of meat was studied. Male Cobb 500 chickens were fed 1 of 4 diets from hatch: control (standard diet with no additives), ZnB (standard diet with added antibiotics), 2% SALmate (standard diet with 2% SALmate, which is composed of 42% fish oil and 58% starch), and 5% SALmate (standard diet with 5% SALmate). A 7-d energy metabolism study was conducted between d 15 and 22 posthatch. Birds were killed at d 25 and intestinal samples were collected to assess microbial communities by terminal restriction fragment length polymorphism and Lactobacillus PCR-denaturing gradient gel electrophoresis. Diet did not affect BW, feed intake, feed conversion, or ileal digestible energy (P > 0.05). Apparent ME was greater in ZnB-fed birds compared with all other diets (P < 0.05). Breast tissue levels of eicosapentaenoic acid, docosahexaenoic acid, docosapentaenoic acid, and total n-3 PUFA were elevated significantly in 2% SALmate- and 5% SALmate-fed chickens compared with control and ZnB diets (P < 0.05). No significant differences in overall microbial communities were observed in the ileum or cecum as assessed by terminal RFLP (P > 0.05). Birds fed 2% SALmate had a significantly different cecal Lactobacillus species profile compared with birds fed the control diet (P < 0.05); however, no differences were observed in birds fed 5% SALmate compared with birds fed all other diets. In addition to the expected increase in breast tissue n-3 fatty acid levels, a low level of dietary n-3 PUFA also altered the intestinal Lactobacillus species profiles. However, n-3 PUFA supplementation did not alter the overall microbial communities or broiler performance.

Aims: Prebiotics are a potential alternative to in-feed antimicrobials to improve performance of chickens. We investigated the effects of mannanoligosaccharide (MOS) and fructooligosaccharide (FOS) on growth, performance and the intestinal microbiota., Methods and Results: Cobb 500 birds were fed either: Control, starter diet without antimicrobials; ZnB, Control + 50 ppm zinc bacitracin; MOS, Control + 5 g kg(-1) MOS; or FOS, Control + 5 g kg(-1) FOS. An energy metabolism study was conducted and intestinal microbial communities assessed by T-RFLP and Lac PCR-DGGE. Diet did not influence performance. Ileal microbial communities were significantly different in ZnB-fed birds compared to all diets, and FOS-fed chickens compared to Control. MOS-fed chickens had a different caecal profile to ZnB and FOS-fed birds. Consensus Lac PCR-DGGE profiles indicated Lactobacillus communities clustered according to diet with Lactobacillus johnsonii characteristic of ZnB diet. Control and MOS-fed chickens displayed significantly different jejunal Lactobacillus profiles to each other whilst ileal profiles were different between MOS and FOS-fed birds., Conclusion: Prebiotics influenced the intestinal microbiota, but did not affect performance., Significance and Impact of the Study: In light of pressure for in-feed antimicrobial withdrawal, the impact of alternative compounds on the intestinal microbiota and bird performance is critical to the poultry industry.

A high-throughput microbial profiling tool based on terminal restriction fragment length polymorphism was developed to monitor the poultry gut microbiota in response to dietary manipulations. Gut microbial communities from the duodena, jejuna, ilea, and ceca of 48 birds fed either a barley control diet or barley diet supplemented with exogenous enzymes for degrading nonstarch polysaccharide were characterized by using multivariate statistical methods. Analysis of samples showed that gut microbial communities varied significantly among gut sections, except between the duodenum and jejunum. Significant diet-associated differences in gut microbial communities were detected within the ileum and cecum only. The dissimilarity in bacterial community composition between diets was 73 and 66% within the ileum and cecum, respectively. Operational taxonomic units, representing bacterial species or taxonomically related groups, contributing to diet-associated differences were identified. Several bacterial species contributed to differences between diet-related gut microbial community composition, with no individual bacterial species contributing more than 1 to 5% of the total. Using canonical analysis of principal coordinates biplots, we correlated differences in gut microbial community composition within the ileum and cecum to improved performance, as measured by apparent metabolizable energy. This is the first report that directly links differences in the composition of the gut microbial community with improved performance, which implies that the presence of specific beneficial and/or absence of specific detrimental bacterial species may contribute to the improved performance in these birds.