Pyrosequencing-based analysis was used to characterize and compare bacterial communities in manure samples of piglets (GSPM) and adult pigs (GBPM) bred with green feeds without additives, and piglets (ASPM) and adult pigs (ABPM) bred with synthetic feeds containing additives. For each sample, 5,010 effective sequences were selected and utilized to do the bacterial composition analysis, respectively. In total, 1,489, 1,327, 941, and 883 operational taxonomic units were obtained at 5 % distance cutoff in GBPM, GSPM, ABPM, and ASPM, respectively. Bacterial phylotype richness in GBPM was higher than the other samples, and ASPM had the least richness. The most dominant class in the four samples is Bacteroidia. Approximately 41 % sequences in GBPM were affiliated with the Clostridiales order. Campylobacter, Clostridium and Streptococcus genera containing pathogenic bacteria were detected in the four samples. Bacterial diversity and abundance in swine manures varied with piglets, adult pigs, and feeds. In the four samples, higher bacterial diversity but less potentially pathogenic bacterial genera in manures of adult pigs bred with green feeds were found, which indicated that those manures were more suitable for resource utilization. This study also provides evidence for the reasonableness of pig farming with green feeds.