Search

Abstract: Laboratory scale digesters were used to study effects of tetracycline (TC) and sulfamethoxydiazine (SMD) on CH4 production from anaerobic digestion of pig manure at 25°C. Tetracycline and SMD were added to digesters at concentrations of 0, 25 and 50mg/L. Results show a delay in initial production of CH4 and lower daily CH4 production peaks with addition of antibiotics compared to control. Cumulative CH4 volumes for all treatments within 20d were lower (P<0.05) than the control indicating that TC and SMD in manure reduced CH4 production. The extent of inhibition on CH4 production depended on the dosage of antibiotics added. Concentrations of TC and SMD in digesters declined rapidly with more than half of the antibiotics disappearing after 12h of digestion, with only trace antibiotics remaining after 2–3d. Rapid disappearance of antibiotics could be due their adsorption onto solid materials or degradation by microorganisms. Antibiotics appear to inhibit bacterial activity resulting in a delay and overall decline in CH4 production. This article is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors; K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson. [Copyright &y& Elsevier]

Abstract: Methane from enteric fermentation and manure decomposition from livestock contributes to greenhouse gas (GHG) emissions. Research on CH4 production from enteric fermentation has mainly focused on ruminant livestock. However, CH4 production from enteric fermentation in pigs may be important due to the large global pig population. This experiment measured enteric CH4 from growing and finishing pigs in China. Five 58.9±1.15kg and five 89.4±0.85kg Duroc×Landrace×Large Yorkshire female pigs were randomly selected from a commercial farm in Shenzhen, Guangdong province (China). The pigs were transferred to individual 2.0m×1.0m×1.2m respiration chambers located on the same farm and continued to be fed the commercial diets of their respective weight group on the farm. After 3 d of adaptation to the respiration chambers, daily CH4 emissions were measured from the 10 pigs for 3 d. The CH4 production of the 60 and 90kg pigs was 1.13 and 2.01g pig/d, respectively, with that of 90kg pigs higher than the 60kg group (P<0.05). When the values are adjusted/kg DM feed intake (i.e., 0.70g/kg DM versus 0.82g/kg DM) and per kg body weight (19.01g/kg versus 22.47g/kg) for the 60 and 90kg groups, there were no differences. Using these values, estimated annual CH4 production from the 60 and 90kg pigs was 0.41kg and 0.73kg, respectively, values which are lower than the 1kg pig/year adopted by the Intergovernmental Panel on Climate Change. The high variation in CH4 emission among our pigs, and those in the literature, suggest that differences in CH4 emission exist among pigs within the same herd housed under similar nutritional and husbandry management. This article is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors; K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson. [Copyright &y& Elsevier]