Nutrient composition and degradation profiles of anthocyanidin-accumulating Lc-alfalfa populations

Abstract

P. 2010. Nutrient composition and degradation profiles of anthocyanidin-accumulating Lc-alfalfa populations. Can. J. Anim. Sci. 90: 401Á412. Alfalfa (Medicago sativa L.) is one of the most used forages in the world but suffers the disadvantage of having poor protein utilization by the animal. The poor protein utilization is the result of excessive ruminal protein degradation, which might be reduced by the protein precipitating capacity of anthocyanidin (AC) and condensed tannins (CT). The objective of this study was to determine the effects of the Lc-transgene on survival, anthocyanidin, condensed tannin and chemical profiles in crossed populations of western Canadian-adapted Lc-alfalfa. These were compared with their nontransgenic (NT) parental varieties, Rangelander, Rambler, and Beaver. Lc-alfalfa forage accumulated enhanced amounts of anthocyanidin, with an average concentration of 197.4 mg g(1 DM, while condensed tannins were not detected. Both of these metabolites were absent in the NT parental varieties. Lc-alfalfa had a lower (24.8 vs. 27.3% DM; PB0.02) crude protein (CP) and higher (58.3 vs. 55.5% DM; P B0.01) carbohydrate (CHO) concentration, which resulted in their decreased (P B0.01) N:CHO ratio (68.1 vs. 79.2 g kg ) compared with NT alfalfa. Slowly degradable N:CHO ratio was decreased by 5.9 g kg (1 (P B0.03) and total rumen-degradable N:CHO ratio was decreased by 12.9 g kg (1 (PB0.03) in Lc-alfalfa compared with NT alfalfa. In conclusion, Lc-gene transformation resulted in the accumulation of anthocyanidin, decreased total protein content, increased total carbohydrate content and improved the balance between nitrogen and carbohydrates in the crossed transgenic populations of western Canadian-adapted alfalfa compared to their NT western Canadian parental alfalfa varieties. La luzerne (Medicago sativa L.) est une des plantes fourrage`res les plus utilise´es dans le monde, cependant elle souffre du fait que les animaux assimilent mal ses prote´ines. Cette pie`tre assimilation re´sulte de l'excessive de´gradation de ses prote´ines dans le rumen, une de´gradation que pourrait freiner le pouvoir de pre´cipitation des prote´ines de l'anthocyanidine et des tanins condense´s. L'e´tude devait pre´ciser les effets du transge`ne Lc sur la re´sistance des prote´ines et la concentration 6

Fermentation, degradation and microbial nitrogen partitioning for three forage colour phenotypes within anthocyanidin‐accumulating Lc‐alfalfa progeny

“…Second‐generation transgenic (T 1 ) Lc ‐alfalfa crossed progeny Beav Lc 1, Ramb Lc 3 and Rang Lc 4 used in this study were developed at Forage Genetics International (West Salem, WI, USA)14 and compared with commercially available parental non‐transgenic (NT) alfalfa cultivars Beaver, Rambler and Rangelander. Seeds from Lc ‐alfalfa progeny and NT‐alfalfa cultivars were sown initially in a greenhouse and then transplanted into a Canadian Food Inspection Agency (CFIA)‐approved experimental field at the Saskatoon Research Centre farm of Agriculture and Agri‐Food Canada (AAFC).…”

“…Seeds from Lc ‐alfalfa progeny and NT‐alfalfa cultivars were sown initially in a greenhouse and then transplanted into a Canadian Food Inspection Agency (CFIA)‐approved experimental field at the Saskatoon Research Centre farm of Agriculture and Agri‐Food Canada (AAFC). Plants that had been genotyped earlier in the field for the presence of the Lc gene14 were phenotyped by forage colour (green, light purple‐green (LPG) and purple‐green (PG)) within each of the three Lc ‐progeny. Field‐grown alfalfa plants were harvested manually with shears at ca 5 cm above ground level on 4 and 25 July and 15 and 25 August 2007 at a vegetative pre‐bud stage according to CFIA‐imposed confined field trial regulations,15 and samples were transported and stored as described by Jonker et al 14 The four harvests were pooled into one sample per phenotype within each Lc ‐progeny (three phenotypes × three Lc ‐progeny) and for each NT‐alfalfa cultivar (three cultivars) to obtain sufficient material for in vitro incubations and analysis of original samples for their chemical and phytochemical composition.…”

“…Plants that had been genotyped earlier in the field for the presence of the Lc gene14 were phenotyped by forage colour (green, light purple‐green (LPG) and purple‐green (PG)) within each of the three Lc ‐progeny. Field‐grown alfalfa plants were harvested manually with shears at ca 5 cm above ground level on 4 and 25 July and 15 and 25 August 2007 at a vegetative pre‐bud stage according to CFIA‐imposed confined field trial regulations,15 and samples were transported and stored as described by Jonker et al 14 The four harvests were pooled into one sample per phenotype within each Lc ‐progeny (three phenotypes × three Lc ‐progeny) and for each NT‐alfalfa cultivar (three cultivars) to obtain sufficient material for in vitro incubations and analysis of original samples for their chemical and phytochemical composition. Prior to conducting in vitro incubations, each pooled sample was freeze‐dried and ground to pass through a 1 mm screen using a cyclonic mill (Retsch SM‐3000, Brinkmann Instruments, Mississauga, ON, Canada).…”

“…Non‐fibre carbohydrates (NFC) were calculated as 1000 − (aNDF + CP + EE + ash) and total carbohydrates (CHO) as 1000 − (CP + EE + ash). Anthocyanidin extractable in methanol/HCl (99:1 v/v) was analysed according to the method described by Jonker et al 14 with cyanidin as standard.…”

Gene-Transformation-Induced Changes in Chemical Functional Group Features and Molecular Structure Conformation in Alfalfa Plants Co-Expressing Lc-bHLH and C1-MYB Transcriptive Flavanoid Regulatory Genes: Effects of Single-Gene and Two-Gene Insertion

“…However, extremely high soluble protein content in alfalfa plants causes major issues when ruminant livestock graze on alfalfa pasture, which include bloating causing animal death, N-to-energy unsynchronization, and nutrients being under-utilized [1,2]. How can we solve these issues?…”