Nutritional Evaluation of Tropical Forage Grass Alone and Grass-Legume Diets to Reduce in vitro Methane Production

TY - JOUR

T1 - Nutritional Evaluation of Tropical Forage Grass Alone and Grass-Legume Diets to Reduce in vitro Methane Production

AU - Quintero-Anzueta, Stiven

AU - Molina-Botero, Isabel Cristina

AU - Ramirez-Navas, Juan Sebastian

AU - Rao, Idupulapati

AU - Chirinda, Ngonidzashe

AU - Barahona-Rosales, Rolando

AU - Moorby, Jon

AU - Arango, Jacobo

N1 - This work was implemented as part of the CGIAR Research Program (CRP) on Climate Change, Agriculture and Food Security (CCAFS), and the Livestock CRP which are carried out with support from CGIAR Fund Donors and through bilateral funding agreements. For details, please visit https://ccafs.cgiar.org/donors. We also acknowledge the financial assistance of BBSRC grants: UK—CIAT Joint Centre on Forage Grasses for Africa (BBS/OS/NW/000009); RCUK-CIAT Newton Fund—Toward climate-smart forage-based diets for Colombian livestock (BB/R021856/1); Advancing sustainable forage-based livestock production systems in Colombia (CoForLife) (BB/S01893X/1) and GROW Colombia from the UK Research and Innovation (UKRI) Global Challenges Research Fund (GCRF) (BB/P028098/1).

PY - 2021/6/14

Y1 - 2021/6/14

N2 - Forage grass nutritional quality directly affects animal feed intake, productivity, and enteric methane (CH4) emissions. This study evaluated the nutritional quality, in vitro enteric CH4 emission potential, and optimization of diets based on two widely grown tropical forage grasses either alone or mixed with legumes. The grasses Urochloa hybrid cv. Cayman (UHC) and U. brizantha cv. Toledo (UBT), which typically have low concentrations of crude protein (CP), were incubated in vitro either alone or mixed with the legumes Canavalia brasiliensis (CB) and Leucaena diversifolia (LD), which have higher CP concentrations. Substitution of 30% of the grass dry matter (DM) with CB or LD did not affect gas production or DM degradability. After 96 h of incubation, accumulated CH4 was 87.3 mg CH4 g−1 DM and 107.7 mg CH4 g−1 DM for the grasses alone (UHC and UBT, respectively), and 100.7 mg CH4 g−1 DM and 113.2 mg CH4 g−1 DM for combined diets (70% grass, 15% CB, and 15% LD). Diets that combined legumes (CB or LC) and grass (UHC or UBT) had higher CP contents, gross, and metabolizable energy (GE, ME, respectively) densities, as well as lower concentrations of neutral detergent fiber (NDF) and acid detergent lignin (ADL). The ME and nutritional variables such as NFD, tannins (T), and CP showed a positive correlation with in vitro net gas production, while ruminal digestibility was affected by CP, ADL, T, and GE. Optimal ratios of components for ruminant diets to reduce rumen net gas production and increase protein content were found with mixtures consisting of 60% grass (either UHC or UBT), 30% CB, and 10% LD. However, this ratio did not result in a decrease in CH4 production.

AB - Forage grass nutritional quality directly affects animal feed intake, productivity, and enteric methane (CH4) emissions. This study evaluated the nutritional quality, in vitro enteric CH4 emission potential, and optimization of diets based on two widely grown tropical forage grasses either alone or mixed with legumes. The grasses Urochloa hybrid cv. Cayman (UHC) and U. brizantha cv. Toledo (UBT), which typically have low concentrations of crude protein (CP), were incubated in vitro either alone or mixed with the legumes Canavalia brasiliensis (CB) and Leucaena diversifolia (LD), which have higher CP concentrations. Substitution of 30% of the grass dry matter (DM) with CB or LD did not affect gas production or DM degradability. After 96 h of incubation, accumulated CH4 was 87.3 mg CH4 g−1 DM and 107.7 mg CH4 g−1 DM for the grasses alone (UHC and UBT, respectively), and 100.7 mg CH4 g−1 DM and 113.2 mg CH4 g−1 DM for combined diets (70% grass, 15% CB, and 15% LD). Diets that combined legumes (CB or LC) and grass (UHC or UBT) had higher CP contents, gross, and metabolizable energy (GE, ME, respectively) densities, as well as lower concentrations of neutral detergent fiber (NDF) and acid detergent lignin (ADL). The ME and nutritional variables such as NFD, tannins (T), and CP showed a positive correlation with in vitro net gas production, while ruminal digestibility was affected by CP, ADL, T, and GE. Optimal ratios of components for ruminant diets to reduce rumen net gas production and increase protein content were found with mixtures consisting of 60% grass (either UHC or UBT), 30% CB, and 10% LD. However, this ratio did not result in a decrease in CH4 production.

KW - Sustainable Food Systems

KW - Canavalia brasiliensis

KW - in-vitro fermentation

KW - Leucaena sp.

KW - nutritional quality

KW - Urochloa brizantha cv. Toledo

KW - Urochloa hybrid cv. Cayman

U2 - 10.3389/fsufs.2021.663003

DO - 10.3389/fsufs.2021.663003

M3 - Article

VL - 5

JO - Frontiers in Sustainable Food Systems

JF - Frontiers in Sustainable Food Systems

SN - 2571-581X

M1 - 663003

ER -