Dietary nitrate metabolism and enteric methane mitigation in sheep consuming a protein-deficient diet

• Autores: Villar, Maria Laura; Hegarty, Roger S.; Van Tol, M.; Godwin, Ian R.; Nolan, John V.
• Año de publicación: 2019
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Animal production science 59. (20 September 2019)
• Materia: Rumiante; Oveja; Metabolismo; Nutrición Animal; Asimilación de Nitratos; Ruminants; Sheep; Metabolism; Animal Nutrition; Nitrate Assimilation; Blood Plasma; Plasma Sanguíneo; Saliva; Dietas Restrictas en Proteínas; Protein Restricted Diets; Cysteamine Hydrochloride
• Institución: Instituto Nacional de Tecnología Agropecuaria

It was hypothesised that the inclusion of nitrate(NO3 –) or cysteamine hydrochloride (CSH) in a protein deficient diet (4.8% crude protein; CP) would improve the productivity of sheep while reducing enteric methane (CH4) emissions. A complete randomised designed experiment was conducted with yearling Merino sheep (n = 24) consuming a proteindeficient wheaten chaff control diet (CON) alone or supplemented with 1.8% nitrate (NO3 –; DM basis), 0.098% urea (Ur, DM basis) or 80 mg cysteamine hydrochloride/kg liveweight (CSH). Feed intake, CH4 emissions, volatile fatty acids (VFA), digesta kinetics andNO3–, nitrite (NO2–) and urea concentrations in plasma, saliva and urine samples were measured. There was no dietary effect on animal performance or digesta kinetics (P > 0.05), but adding NO3– to the CON diet reduced methane yield (MY) by 26% (P = 0.01). Nitrate supplementation increased blood MetHb, plasma NO3– and NO2– concentrations (P < 0.05), but there was no indication of NO2– toxicity. Overall, salivary NO3– concentration was greater than plasma NO3– (P < 0.05), indicating that NO3– was concentrated into saliva. Our results confirm the role of NO3– as an effective additive to reduce CH4 emissions, even in a highly protein-deficient diet and as a source of additional nitrogen (N) for microbial protein synthesis via N-recycling into saliva and the gut. The role of CSH as an additive in low quality diets for improving animal performance and reducing CH4 emissions is still unclear.
Estación Experimental Agropecuaria Bariloche
Fil: Villar, Maria Laura. Instituto Nacional de Tecnología Agropecuaria (INTA). Estacion Experimental Agropecuaria Bariloche; Argentina
Fil: Hegarty, Roger S. University of New England. School of Environmental and Rural Science; Australia
Fil: Van Tol, M. Wageningen University and Research. Animal Nutrition Group; Holanda
Fil: Godwin, Ian R. University of New England. School of Environmental and Rural Science; Australia
Fil: Nolan, John V. University of New England. School of Environmental and Rural Science; Australia