Effect Of Field Pea And Multicarbohydrase Enzymes Inclusion On Growth, Diet Digestibility, And Greenhouse Gas Emissions Of Finishing Pigs And Their Manure

Abstract

Introduction of field pea into a crop rotation cycle can reduce the use of nitrogenous fertilizers. Nitrogen fertilizer production and application is one of the largest greenhouse gas (GHG) emission sources from crop production. Multicarbohydrase enzymes improve diet digestibility by breaking down resistant starch and non-starch polysaccharides (NSPs), thereby reducing manure organic matter (OM). We hypothesized that the inclusion of field pea and multicarbohydrase enzymes in a finisher pig diet would mitigate GHG emissions from pork production. Three studies were conducted to determine the effect of field pea and multicarbohydrase enzymes inclusion in finisher pig diet on digestibility, growth performance and GHG emissions of pork production. Inclusion of 40% inclusion of field pea resulted in no difference in average daily gain (ADG), average daily feed disappearance (ADFD), gain to feed ratio (G:F), days to market or carcass traits compared to feeding a conventional wheat-barley based diet. Multicarbohydrase enzymes inclusion had no effect on growth performance or carcass parameters. Inclusion of 20 and 40% field pea decreased apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE), and N, but increased acid detergent fibre (ADF), neutral detergent fibre (NDF) digestibility compared with feeding the control diet. Inclusion of multicarbohydrase enzymes resulted in an increase in ADF digestibility. There were no field pea-enzyme interactions on animal growth or nutrient digestibility. The addition of field pea to the diet resulted in a shift from urinary to fecal N excretion. The 40% dietary inclusion of field pea did not affect carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) production from pig housing and stored manure. Multicarbohydrase enzymes inclusion reduced CO2 emissions from pig housing, however manure associated emissions were unaffected. An LCI (life cycle inventory) evaluating emissions from combined crop production and pig housing found a 13% reduction in global warming potential (GWP). The GWP from pig housing increased with 40% inclusion of field pea, but multicarbohydrase enzymes inclusion showed a decrease. The inclusion of up to 40% field pea and multicarbohydrase enzymes to the diet of finishing pigs has the potential to reduce overall GHG output of pork production.