Nitrate in the ruminant nutrition as a strategy for mitigation of enteric methane

Abstract

Enteric methane production is the main source of greenhouse gases emissions from agricultural activities and generates energy loss to the animal up to 12% of gross energy consumption. Recent works bring gaps to be answered before testing the hypothesis related to nitrate as methane mitigating agent in animals on pasture, such as on the palatability of the product encapsulated nitrate and the influence feeding behavior of sheep.The objective of this study is to evaluate the use of nitrate in the ruminant nutrition as a strategy aimed at mitigation of enteric methane emission and energy loss decrease due to methanogenesis. The experiment will be consisted in three phases. Phase I: Diets were test using the in vitro gas production in a semi-automatic system to determine the best diet to be tested in vivo. Phase II: The diets what have the best obtained results in phase I, were evaluated in vivo. For this, six rumen cannulated lambs were distributed in experiment 6 x 6 Latin square. Experimental treatments were be consisted by the inclusion of nitrate in the diet (% DM) in the gradual replacement of soybean meal. The levels of soybean meal replacement by nitrate were defined based on the equivalent protein so as to leave the diets isonitrogenous. In that phase ruminal metabolism, nitrogen metabolism, toxicity of diets and CH4 emission rate by technique of semi open chamber were evaluated. Given the challenges arising from recent research, the new scope for Phase III: will investigating the palatability and feeding behavior of sheep supplemented with PNE product as diet selected in Phase II. In this fhase 14 lambs with an average whethe of 26.5 kg will will be distributed in a randomized block design in three treatments. T1) lambs receiving diet based on soybean and corn and hay Tifton (60% concentrate: 40% roughage); T2) diet equal treatment 1 with palatability additions; and T3) diet treatment 1 with inclusion of 3% nitrate encapsulated product replacing soybean meal as non-protein nitrogen source. Both diets will be offered for three flavor: patterns, sweet and bitter. The inclusion of 3% of nitrate was selected according to the results of the second phase of this project. We will evaluate the palatability of the diet; feeding behavior, intake, water balance and methemoglobinemia.