Nutritional intervention in early life to manipulate rumen microbial colonization and methane output by kid goats post-weaning

The growing interest in reducing methane (CH4) emissions from ruminants by dietary means is constrained by the complexity of the microbial community in the rumen of the adult animal. The aim of this work was to study whether intervention in early life of kids has an impact on methane emissions and the microbial ecosystem in the rumen and whether the effects persist post-weaning. Sixteen doe goats giving birth to 2 kids each were randomly split into two experimental groups: 8 does were treated (D+) with bromochloromethane (BCM) after giving birth and over 2 mo, while the other 8 does were not treated (D-). In both groups of does, 1 kid per doe was treated with BCM (k+) for 3 mo while the other was untreated (k-), resulting in four experimental groups: D+k+, D+k-, D-k+ and D-k-. Methane emissions were recorded and ruminal samples collected from kids at 2 mo of age (weaning, W), and 1 (W+1) and 4 (W+4) mo after. At W+1 mo, CH4 emissions by k+ kids were 52% and 59% lower than untreated kids (in D+ and D- groups, respectively). However, at W+4 mo, only D+k+ kids remained lower (33%) emitters and exhibited higher daily weight gain (146 g/d) compared to the other three groups (121.8 g/d). The analysis of the archaeal community structure by DGGE showed a strong effect of BCM treatment on does and kids, that persisted only in D+k+ kids. The study showed that the application of BCM during early life of kids modified the archaeal population that colonized the rumen, which resulted in lower CH4 emissions around weaning. The effect is influenced by the treatment applied to the doe and persisted 3 months later in D+k+ kids.