Transformation with TT8 and HB12 RNAi Constructs in Model Forage (Medicago sativa, Alfalfa) Affects XXXX Structure and Metabolic Characteristics in Ruminant Livestock Systems.

@entity3918 @entity1735 @entity4383 @entity35839 @entity435
UNASSIGNED: Lignin, a @entity35839 polymer present in secondary cell walls, has a negative impact on feed digestibility. TT8 and HB12 genes were shown to have low expression levels in low-lignin tissues of alfalfa, but to date, there has been no study on the effect of down-regulation of these two genes in alfalfa on nutrient chemical profiles and availability in ruminant livestock systems. The objectives of this study were to investigate the effect of transformation of alfalfa with TT8 and HB12 RNAi constructs on @entity1735 ( @entity435 ) structure and @entity435 nutritive value in ruminant livestock systems. The results showed that transformation with TT8 and HB12 RNAi constructs reduced rumen, rapidly degraded @entity435 fractions (RDCA4, P = 0.06; RDCB1, P < 0.01) and totally degraded @entity435 fraction (TRDCHO, P = 0.08). Both HB12 and TT8 populations had significantly higher in vitro digestibility of neutral detergent fiber (NDF) at 30 h of incubation (ivNDF30) compared to the control (P < 0.01). The TT8 populations had highest ivDM30 and ivNDF240. @entity4383 with TT8 and HB12 RNAi constructs induced molecular structure changes. Different @entity435 functional groups had different sensitivities and different responses to the transformation. The @entity435 molecular structure changes induced by the transformation were associated with predicted @entity435 availability. Compared with HB12 RNAi, transformation with TT8 RNAi could improve forage quality by increasing the availability of both NDF and @entity3918 . Further study is needed on the relationship between the transformation-induced structure changes at a molecular level and nutrient utilization in ruminant livestock systems when lignification is much higher.
