[Methanogen diversity in the piglet colon and its correlation with environmental factors]

We investigated the correlation between the methanogen diversity in the piglet colon and the environmental factor (weaning stress, diet type and age).

The colonic contents of piglets at 7, 14, 21, 28 and 35 days old were collected for the determination of volatile fatty acids and total DNA extraction. DNA was subject to PCR-DGGE (Denaturing gradient gel electrophoresis) analysis and interesting bands were excised and sequenced. Redundancy analysis (RDA) was performed for the correlation between methanogen diversity and environmental factors.

As the piglets grew, acetate, propionate and the total volatile fatty acid production increased significantly (P < 0.05), but butyrate concentration remained stable (P > 0.05). The similarity indices of DGGE profiles was higher during the period of the 7 day to 24 day after birth, with grouped in one cluster, and the samples from the 35 days were dropped into another cluster. DGGE analysis showed three dominant bands appeared in samples of 35 d old, with their 16S rRNA gene sequences closely related to Methanobacteria and a novel group of uncultivated Achaean. Redundancy analysis (RDA) showed that age has the largest relevance to the community structure of bacteria in colonic samples, followed by the diet type.

The results indicated that the methanogen community in the piglet colon was stable during the first 24 days after birth, and became more diverse at 35 days of age. The methanogens community was mainly affected by age and the diet type.