Determining The Carbon And Nitrogen Budget From Growing Process Of Caged Broilers

The broilers industry is currently facing new challenges with respect to environmental impacts of manure management and nutrient loss from broilers production facilities. Broilers production continue to become larger and more concentrated, leading to a greater concentration of nutrients in the form of waste products such as manure and waste gas emissions. The objective of this research was to determine the respective content of carbon (C) and nitrogen (N) in the feed input and the output of broiler and its manure, and analyze the broilers emission of C and N budget through mass balance, to provide emission rates of methane and carbon dioxide for livestock greenhouse gas inventories and potential mitigation technologies. Understanding the fate of N inputs and outputs from commercial broiler operations is important for increasing N efficiency and reducing N emissions. Firstly, NH₃ and GHGs emissions from three commercial high-rise broiler house(102m×7m×2.8m) with mechanically-ventilation system were monitored by using INNOVA 1312 multi-gas monitor with multi-channel samplers. Building ventilation rates were determined by calibrated on site FANS measurement systems. A total direct measurement C and N balance trial was conducted on broilers from 0 to 42 d of age with all C and N inputs and outputs measured. The main conclusions are as follows:1. The NH₃ emission rates show the expected dependence on the NH₃ concentrations and house ventilation rates,with the daily emissions ranging from 8.5 to 342.1 mg·d^-1·bird^-1 and an average daily emission rate of 137.9 mg.d^-1.bird^-1 (48.6 g·day^-1·AU^-1) over the 42-d period.The GHGs emission rates were 19.5-351.9 mg·d^-1·bird^-1 with an average of 154.5 mg·d^-1·bird^-1 (54.4 g·day^-1·AU^-1) for CH₄, 2.2^-152.9 g·d^-1·bird^-1 with an average of 65.9 g·d^-1.bird^-1 (23.2 kg·day^-1·AU^-1) for CO₂. No emissions of N₂O was observed neither during the growth of the broiler nor above the manure at the end of the experiment.The rise in estimated CH₄ and CO₂ emission rates from o to 42 d occurred along with an increase in broilers weights. NH₃ emission factors showed a trend first and then decreased.2. The total NH₃ emission over the 42 d averaged 5.65±1.02g·bird^-1·life cycle^-1(weight of 2680±27.9g). The majority of TAN, specifically 36.4%, was emitted during from 18 to 27 d (growing phase 2,GP2),with 33.6% in growing phase 1 (GP1) and 29.9% in Growing phase 3(GP3). GP2 of the NH₃ emission factors were significantly higher than the cumulative GP1 and GP3. CH₄ and CO₂ cumulative emission rates was 6.30±0.16g·bird^-1·life cycle^-1, 2.68±0.18 kg·bird^-1·life cycle^-1, respectively. The cumulative emission rates of CH₄ and CO₂ in GP3 were significantly higher than emission rates in GP1 and in GP2 (P <0.0001), accounting for total emissions of 50%.3. Estimated carbon and nitrogen budget over the whole rearing period. Broiler total intake of carbon and nitrogen over the 42-d period were 53.13 g N·kg^-1, 622.9 g C·kg^-1, respectively. Carbon and nitrogen intake in drinking water can be ignored. Broiler nitrogen accumulation in the ranging from 29.9 to 33.2 g N·kg^-1, with an average of 31.1 g N·kg^-1.The range of carbon accumulation in broiler was 186.9～207.6 g·kg^-1, averaging 195.0 g·kg^-1.Manure carbon and nitrogen accumulation was 139.9 g C·kg^-1, 18.3 g N·kg^-1, respectively.4. At the end of 42-d growth period, the N recovery relative to the total feed N intake was 148.2±3.78 g N·bird^-1 (mean±SD) 58.6±2.20% in live birds, 34.5±1.42% in manure, and 3.14±0.60% in TAN emissions, with the amount of N₂O emitted being negligible. The C input recovery relative to the total feed C intake was 1,738±33.4 g C·bird^-1,31.3±1.17% in live birds, 22.5±0.11% in manure, 41.4±3.47% in CO₂-C emissions, and 0.27±0.01% in CH₄-C emissions. The C and N accumulation of the market broilers was, respectively, 544 g·bird^-1 and 86.9 g·bird^-1, whereas the manure C and N accumulation was, respectively, 390 g C·bird^-1 and 51.1 g N·bird^-1. The total TAN emission over the 42 d averaged 4.65±0.84g·bird^-1·life cycle^-1.Total CH₄-C and emissions were estimated to 4.72 g·bird^-1·life cycle^-1 and 0.73±0.05 kg·bird^-1·life cycle^-1.5. Broilers house carbon and nitrogen balance Day-old chicks and all feed entering the facility were considered to be all the C and N input. Day-old chicks represented less than 1% of all C and N input, while feeds were calculated to be greater than 99% of all C and N inputs. After 42d, the percentage of N input recovered was as follows: 60.4% in live broilers, 1.3% in dead chicken, 0.4% in water, 32.2% accumulated in the litter, and 2.9% in TAN emissions. The percentage of C input recovered was as follows: 31.1% in live broilers,0.8% in dead chicken,22.9% accumulated in the litter,0.1% accumulated in water,42.3% in CO₂-C emissions, 0.3% in CH₄-C emissions...