The poultry market is expected to increase by 17.8 % by 2030, with poultry meat consisting of 41 % of the global meat market (FAO, 2023). The demand for poultry is driven by its affordability and nutritional content (FAO, 2023). The United States produces the most poultry products worldwide, with broiler (meat chicken) production consisting of 67 % of total poultry sales (USDA, 2023). Because of the rising demand, broiler producers must implement practices to improve efficiency and bird productivity while meeting bird welfare and sustainability standards.
Broiler farms may contain multiple houses with flocks ranging from 23,000 birds per house to 56,000 in larger facilities (ACES, 2022, MSDAC, 2023). Birds are grown on a substrate called litter, which is a heterogeneous mixture of bedding material (wood shavings, sawdust, rice hulls), excreta, spilled feed, wasted water, and feathers. Birds are in contact with litter throughout the grow-out cycle, and litter quality has a substantial impact on performance and welfare (Nagaraj et al., 2007). Poor litter conditions prevent broilers from reaching their genetic potential, and ultimately cause economic losses (Ritz et al., 2017). Continuous excreta deposition into the litter contributes to high moisture, ammonia (NH3) concentrations, and microbial loads, all of which negatively impact bird health (Tabler et al., 2021). High pH and moisture promote the generation of ammonia gas, which can cause irritation to birds’ skin, eyes, and lungs, and decrease growth rate (Martland, 1984; Nairn and Watson, 1972; Nagaraj et al., 2007). In addition, excess moisture provides favorable environments for pathogens and NH3-generating bacteria to grow (Ritz et al., 2017). A litter moisture range of 20-25 % is optimal and can mitigate excess NH3 volatilization and microbial growth (Ritz et al., 2017). NH3 levels should not exceed 25 ppm because it negatively affects bird and worker health (Miles et al., 2004; Sheikh et al., 2018).
Chicken feet (paws) are a major export to overseas markets. Paws bring in more revenue than chicken legs, falling just behind breast and wing revenue (USPEEC, 2009). If NH3 and moisture are not managed effectively, it can become a threat to paw quality, eye health, and the respiratory system. Furthermore, footpad lesions allow bacteria from the litter to infect the bird, which can result in weight loss, stunted growth, and death (Tabler et al., 2022). Footpad quality is used as a criterion to audit bird welfare in the United States and Europe (Martland, 1985; Mayne, 2005).
One strategy to mitigate NH3 is to apply litter amendments. Commonly used amendments include acidifiers, such as Poultry Litter Treatment® (PLT). PLT consists of sodium bisulfate and reduces NH3 volatilization through reducing litter pH. Litter pH typically ranges between a pH of 7.5 to 8.5, and NH3 is present in a gaseous phase at a pH > 8.0 (Ritz et al., 2017). Reducing NH3 volatilization also sequesters nitrogen in the litter as non-volatile ammonium (NH4+), which increases its value as a fertilizer and reduces the release of air pollutants. However, studies indicate that litter acidifying agents, including PLT, can lose effectiveness after 14 to 21 days (Ritz et al., 2017; Linhoss et al. 2019). PLT does not affect litter moisture, and excess moisture can contribute to increased NH3 volatilization (Terzich et al., 1998).
Lowering litter pH can reduce overall bacterial populations, including NH3-generating bacteria that grow in basic environments (Ritz et al. 2017). However, in a bench-scale study, PLT application resulted in significantly higher E. coli populations than the control litter (Mohammadi-Aragh et al., 2022b). The study also reported that total aerobic bacteria populations were comparable between PLT-treated litter and the control litter. Similarly, a study conducted by Pope and Cherry (2000) found no statistical difference between PLT-treated and control litter bacterial loads after one week following PLT application. The varying results of PLT on bacterial populations indicates that its application may not significantly reduce bacterial populations in all cases. Researchers need to improve the understanding of PLT’s impact on litter bacteria and moisture to provide integrators with reliable information.
Biochar (BC) is a highly stable and porous material that is generated as a byproduct in some agricultural and forest products operations. In Mississippi, forestry is the third largest agricultural industry and wood is a dominating agricultural commodity in the southeastern United States (MSDAC, 2023). Some operations use wood wastes (sawdust, trimmings, shavings, etc.) to generate electricity for the plants through gasifying the wastes at high-temperature, low-oxygen conditions. The solid byproduct of the gasification process is a charred material, known as BC. BC has a high surface area and porosity that confer absorptive and adsorptive properties. BC morphology and chemical characteristics are affected primarily by pyrolysis conditions and feedstock (Ippolito et al., 2020). BC has been extensively studied in agricultural applications and it has been shown to be an effective soil amendment and soil conditioner. In addition, it is currently being studied to determine its effectiveness as a broiler litter amendment. Previous research has found that BC increases water-holding capacity and reduces NH3 volatilization in broiler litter without negatively impacting bird performance (Linhoss et al., 2019). However, there is limited information on BC as a litter amendment in broiler facilities and how it compares to conventional amendments regarding litter quality and bird performance.
Water activity (Aw) is a thermodynamic property that describes the availability of the water to escape. Specifically, Aw is defined as the vapor pressure of water in a system divided by that of pure water at the same temperature (Fernández, 2011). It is commonly used in the food industry to determine the amount of free water available for microbial metabolism (Van Der Berg and Bruin, 1981). Aw may also be useful for a more in-depth evaluation of moisture in various environments and for determining the amount of bioavailable water for microorganisms. There are limited studies of how BC impacts Aw in broiler litter environments; however, previous research demonstrated a positive relationship between MC and Aw (Dunlop et al., 2016a; Linhoss et al., 2023).
Because BC’s effectiveness as a litter amendment is poorly understood, the study aimed to compare how BC compares to PLT as a litter amendment with regards to NH3 volatilization and live performance of broilers grown to 42 d. In addition, the impact of litter amendments on Aw, MC, and pH was evaluated. The current study intends to bridge this knowledge gap and provide integrators information on the effects of BC on litter quality and live bird performance compared to PLT.
MATERIALS AND METHODS
Experimental Design
A total of 660 straight run Ross 708 chicks were obtained from a local commercial hatchery on the day of the trial. Chicks were randomly distributed among 15 environmental chambers (1.52 × 2.74 m) containing used litter with 44 birds per chamber. The litter was used in a previous trial at the USDA-ARS Poultry Research Unit in Mississippi State, MS. The chambers were equipped with two tube feeders, a nipple drinker line, and one 5000K LED bulb. Birds had access to food and water ad libitum. The trial began on October 4th, 2023 (d 0) and ended on November 15th, 2023 (d 42). The air temperature was adjusted from 33 °C at d 0 to 22 °C at d 42.
Birds were fed three phases of feed diets: starter (d 1 – d 14), grower (d 15 – d 28), and finisher (d 29 – d 42), all of which met or exceeded NRC recommendations (NRC, 1994). Diet formulations are reported on a percent-by-mass basis and not the complete diet formulation. Methionine, lysine, threonine, and valine were included as crystalline feed-grade amino acids for DL-methionine, L-lysine, L-threonine, and L-valine, respectively. Choline was included as 70 % choline chloride salt. The starter diet consisted of 56.14 % corn, 37.55 % soybean meal, 2.97 % soy oil, 0.36 % methionine, 0.23 % lysine, 0.16 % threonine, 0.09 % choline, and 0.05 % valine. The grower diet consisted of 62.86 % corn, 31.27 % soybean meal, 2.55 % soy oil, 0.20 % methionine, 0.20 % lysine, 0.10 % threonine, 0.07 % choline, and 0.02 % valine. Lastly, the finisher diet consisted of 67.14 % corn, 27.99 % soybean meal, 2.42 % soy oil, 0.30 % methionine, 0.20 % lysine, 0.08 % threonine, and 0.06 % choline. Starter, grower, and finisher diets comprised 21.55 %, 19.32 %, and 18.57 % crude protein, respectively. Corn and soybean meal contained 6.50 % and 46.50 % crude protein, respectively. Digestible lysine levels were 1.21 %, 1.06 %, and 1.00 % for starter, grower, and finisher diets, respectively.
Chambers were checked daily for mortalities, and five birds from each treatment were weighed on d 14 and 42. Paw quality was assessed on day 42 to assign footpad scores (FPS). Scores were assigned based on three degrees of skin lesion severity: 0 = no visible lesions; 1 = mild lesions; 2 = severe lesions (Ekstand et al., 1998). All methodologies and procedures were approved for this study by the USDA Agricultural Research Service Animal Care and Use Committee.
Pine (Pinus spp.) BC was collected from a local commercial sawmill in Mississippi. The BC was generated at 700 – 1000 °C and was air dried prior to sieving. BC was sieved to a particle size range of 750 – 1400 µm and was surface applied to used broiler litter at a 30 % inclusion rate (vol/vol). Poultry Litter Treatment® (PLT) was surface applied at 0.73 kg∙m-2, following the manufacturer’s instructions (Jones-Hamilton Co., Walbridge, OH, USA). Litter treatments of BC and PLT were applied the day before chick placement (d 0) (Fig 1). Litter samples were collected on the morning before chicks were introduced to form a baseline measurement MC and Aw. Litter NH3 was also analyzed on d 0 before chicks were placed.
Fig. 1. Litter treatments were applied the day prior to chick placement: Control (a), BC (b), PLT (c).
Equilibrium NH3 concentration was analyzed using a stainless-steel dynamic flux chamber connected to a LumaSense photoacoustic field gas monitor (Innova-1412, LumaSense Technologies, Inc., Santa Clara, CA, USA). Woodbury et al. (2006) provides a description of the flux chamber’s construction and functionality, and a similar protocol was followed as Davis et al. (2015). A stir fan (Radio Shack model 273-240, Radio Shack, Fort Worth, TX) was attached to the top of the flux chamber’s interior to promote uniform gas distribution. The flux chamber was placed on the surface of the litter at approximately the same location in each chamber. NH3 concentrations (ppm) were recorded after a 20 min run time. The flux chamber was then cleaned with disinfectant wipes and ran for 2 min to allow clean air to pass through before reading the next sample. Litter NH3 concentrations were measured on d 0, 14, 28, and 41.
Litter treatments included BC, PLT, and a control of no litter amendment. Each treatment contained five replicate chambers. Two composite samples were collected per chamber for MC, Aw, pH, and nutrient analysis on d 0, 17, 29, and 41. A portion of the samples were set aside for nitrogen, phosphorus, potassium (N-P-K) and pH analysis, which were stored at -20 °C until submission to the Mississippi State Chemical Laboratory. Nutrient analysis data were reported as the nutrient percentage on a dry matter basis. Briefly, total nitrogen was determined using an Elementar vario El Cube (Elementar Americas, Inc., Ronkonkoma, NY), and pH was measured by mixing 20 mL of deionized water with 5 g of litter sample. The pH was measured after 30 min. Chamber temperature and relative humidity (RH) were measured with combination probes (HMP60, Vaisala, Helsinki, Finland). Data were recorded at two-minute intervals using a datalogger (CR1000X, Campbell Scientific, Logan, UT, USA) through an analog multiplexer (VOLT116, Campbell Scientific, Logan, UT, USA). MC was measured using an oven-drying protocol described in the ASAE S358.2 standard (ASABE, 2008). Wet-basis moisture content was calculated using Equation 1.(1)
A dewpoint soil water potential meter (WPAC, Meter, Pullman, WA) was calibrated with 0.50 mol∙kg-1 KCL per the manufacturer’s instruction. Aw was then measured at 25 °C, and Equation 2 was used to convert the water potential data to Aw.(2)
BC physiochemical characteristics were measured at the Mississippi State University Department of Chemistry. Total pore volume (PV), pore diameter, and specific surface area (SSA) were measured using Brunaeuer-Emmet-Teller (BET) analysis (Micrometircs, Tristar II Plus, Norcross, GA) using N2 as the adsorption gas at 77 K. BC ultimate analysis was conducted using an elemental analyzer (Elementar, Unicube, Langenselbold, Hesse, Germany). Oxygen percentage was calculated by subtracting N, C, S, and H percentages from 100. Ash content was determined by comparing sample weights before and after placing them in an oven at 600 °C for 24 hr.
Statistical Analysis
The study consisted of litter treatments (BC, PLT, and control), and four sampling days. Each treatment included five replicate chambers, and each chamber was considered the experimental unit. Results were analyzed using Statistical Analysis Software (SAS) using PROC MIXED (SAS, 2022). Means were separated using Fisher’s LSD and PDMIXX800. Bird performance data was analyzed using PROC GLIMMIX in SAS and, means were separated using Fisher’s LSD. Mortality data was arcsin transformed. A significance level of P ≤ 0.05 was used for all statistical analyses.
RESULTS AND DISCUSSION
Pine (Pinus spp.) BC ultimate analysis showed a composition of carbon (91.4 %), O (2.1 %), N (0.2 %), H (1.3 %), S (0.1 %), and ash (4.9 %). These chemical compositions are consistent with a previous study using pine BC from the same source (Mohammadi-Aragh et al., 2022a). BET analysis revealed a lower SSA and PV than BC used in the previous trial, but a larger pore diameter. SSA, PV, and pore size were 5.12 m2 g-1, < 0.0022 cm3 g-1, and 17.3 Å, respectively. In the previous study using pine BC, the SSA and PV were 34.65 m2 g-1 and 0.009 cm3 g-1, respectively. Pore diameter in the current BC measured 6.37 Å longer than BC used previously. It is expected that BC sourced from local operations would have variability in morphological and physiochemical properties, which should be considered prior to use. The BC pH used in this study was 9.97.
Litter treatment, grow-out time, and their interaction had a significant impact on NH3 volatilization (P < .0001) (Table 1). Overall, BC demonstrated the highest NH3 levels (43 ppm) and PLT the lowest (4 ppm). The mean BC NH3 concentrations were likely higher due to increased NH3 production later in the grow-out cycle (Fig 2a). At day 41, mean NH3 concentrations were 104 ppm for BC-treated rooms, which was over the recommended levels of 25 ppm (Miles, 2004) (Fig 2a). This concentration was significantly elevated compared to the control (5 ppm) and PLT (9 ppm) at d 41. However, BC-treated litter did not have abnormally high MC or pH at d 41, indicating there are other factors driving the high NH3 levels. Reviewing the data from day 41 BC treatments indicated all BC-treated chambers contained high equilibrium NH3; therefore, the mean concentration was not skewed by one or two anomalous readings. The cause of the elevated NH3 is unknown and needs further investigation. Litter NH3 decreased from days 0 to 28 for the control and BC-treated litter, and there was no significant change in NH3 between days 28 and 41 for PLT and the control.
Table 1. Broiler litter characteristics and equilibrium ammonia concentrations over a 42 d grow-out
| Treatment | Total N ( %) | Phosphorus ( %) | Potassium ( %) | pH | Aw | NH3 (ppm) | MC ( %) |
|---|---|---|---|---|---|---|---|
| Amendment | |||||||
| Control | 3.85b | 3.63 | 5.26ab | 6.99ab | 0.68 | 23.91b | 21.48a |
| PLT | 3.98a | 4.10 | 5.69a | 6.69b | 0.71 | 4.58c | 21.02a |
| Biochar | 3.10c | 3.10 | 4.50b | 7.18a | 0.66 | 43.17a | 16.01b |
| SEM | 0.03 | 0.34 | 0.31 | 0.11 | 0.02 | 4.44 | 0.02 |
| P-value | <.0001 | 0.0883 | 0.0174 | 0.0031 | 0.2048 | <.0001 | 0.0250 |
| Time | |||||||
| Day 0 | 3.30d | 3.73ab | 4.94b | 7.09a | 0.56c | 40.96a | 12.58c |
| Day 17 | 3.53c | 3.80a | 5.19a | 7.13a | 0.52d | 8.80b | 12.89c |
| Day 29 | 3.73b | 3.55bc | 5.27a | 6.89b | 0.79b | 6.28b | 22.53b |
| Day 41 | 4.01a | 3.36c | 5.19a | 6.69c | 0.86a | 39.51a | 30.03a |
| SEM | 0.05 | 0.21 | 0.19 | 0.21 | 0.02 | 3.54 | 0.001 |
| P-value | <.0001 | 0.0010 | 0.0118 | <.0001 | <.0001 | <.0001 | <.0001 |
| Interaction Effect | |||||||
| P-value | 0.0013 | 0.2428 | 0.0773 | <.0001 | 0.873 | <.0001 | 0.889 |
Meansa-d within the same column that do not share a similar letter are significantly different at P ≤ .05. Total Nitrogen, phosphorus, and potassium are reported as % of dry weight.
Phosphorus is reported as % of P2O5.
Fig. 2. Combined mean interaction effect responses for equilibrium NH3 concentration (a), MC (b), pH (c), and Aw for litter treatments over time. The LS-means are provided for NH3 and pH because their litter treatment x time interaction effect was significant at P ≤ 0.05. a-fMeans that do not share a letter are significant at P ≤ 0.05.
Initial NH3 measurements were elevated for the control and BC, which can be attributed to preheating the chamber (Purswell et al. 2013). In addition, factors such as oxygen, moisture, and carbon-nitrogen ratio can impact NH3 volatilization (Wang et al., 2015). The low NH3 concentrations for the control over time are inconsistent with previous studies that reported an increase in NH3 for untreated broiler litter. (Purswell et al., 2013; Calvet et al., 2011; Hile et al., 2012; Reece et al., 1979; Singh et al., 2009; Choi and Moore 2008) (Fig 2a). The cause of the low NH3 measurements at d 28 and 41 for the control is unclear; however, the litter pH for the control was 6.9 and 6.6 on d 28 and 41, respectively. It is possible that more nitrogen was stored in the litter as non-volatile NH4+. Although no issues with the photoacoustic gas monitor were reported during the experiment, future studies will consider using a second device to verify NH3 concentrations.
Treatment and grow-out time had a significant effect on MC; however, there was no interaction effect (P = 0.889) (Table 1). BC-treated litter had the lowest average MC at 16 %. This may be attributed to BC’s porosity and surface area that help absorb moisture. All treatments significantly increased in MC from day 17 to 41. This was likely a result of increased moisture deposition as birds matured. At day 41, all treatments were above the recommended threshold for MC (25 %); however, BC was closest to the recommended levels (25.8 %) (Collett, 2012). The results suggest that BC may be effective at reducing litter MC; however, an extended trial would give greater insight into BC’s effect on moisture. The mean RH across all chambers ranged from 63.3 % – 65.8 %, with an overall mean of 64.1 % RH. The RH was within the recommended range of 50 % – 70 % (Winn and Godfrey, 1967).
Litter amendment did not significantly affect Aw; however, grow-out time had a significant effect (P <.0001). Similar to MC, Aw would increase as birds matured and deposited more moisture into the litter. There were no significant interaction effects for Aw (P = 0.873). Aw measures the amount of free water in a system that can be used by microorganisms. The minimum Aw for pathogens such as Salmonella spp., Escherichia coli, and Clostridium perfringes is 0.95, indicating the litter from this study was not at high risk of pathogen colonization (Barbosa-Canovas et al., 2008). However, litter MC and Aw likely vary within a pen, with higher water deposition found near drinker lines. Drinker line spillage and leaks are a primary moisture source in broiler operations (Dunlop et al., 2015, Dunlop et al., 2016b). Wet litter promotes the proliferation of microorganisms, including pathogens. (Agnew and Leonard, 2003, Wadud et al., 2012, Ritz et al., 2017).
The application of PLT and BC on day 0 resulted in a significant reduction in NH3 compared to the control (Fig 2a). However, there was no statistical difference between the control and PLT from d 14 – 41. PLT can lose its efficacy after approximately 14 – 21 d, which is consistent with the current findings (Ritz et al., 2017; Linhoss et al., 2019). The pH results also showed that PLT caused a significant reduction in pH at d 0 compared to the control but were comparable to the control and BC treatments from d 29 – 41 (Fig 2c). The primary purpose of PLT is to lower litter pH to reduce NH3 volatilization; however, this study indicates PLT’s acidifying properties are diminished around 29 d, or halfway through a typical commercial broiler grow-out of 56 d (Danko, 2023). However, PLT treatments and control groups NH3 concentrations did not exceed recommended levels of >25 ppm after d 14. Studies have found that multiple applications of PLT on a biweekly basis reduce NH3 generation throughout the grow-out cycle (Purswell et al., 2013). This may be an effective method to maintain NH3 reductions in commercial broiler houses; however, more research is needed to evaluate the effects of multiple PLT applications on equipment and operational costs (Purswell et al., 2013).
The effects of litter treatment, time and their interaction on nutrients are provided in Fig. 3. Total nitrogen was highest in PLT-treated litter at 3.98 % (32.2 g kg-1), likely due to a lower pH that favored N retention. BC-treated litter contained the least nitrogen at 3.10 % (25.4 g kg-1). The nitrogen content reported in this study for BC amended litter is similar to previous results that reported a nitrogen content of 24.7 g kg-1 (Linhoss et al., 2019). Additionally, the study reported a litter pH for control and BC-amended litter of 6.68 and 6.79, respectively, at day 35 (Linhoss et al., 2019). These results were comparable to the current study, which reported a pH of 6.95 and 6.59 for d 41 BC treatments and the control, respectively. Nitrogen increased over time for all treatments, and there was an interaction effect between treatment and time (P = 0.0013) (Fig. 3a). An increase in nitrogen over time is likely due to the increased deposition of nitrogen-rich excreta as birds matured. Overall, PLT-treated litter was not statistically different regarding pH when compared to the control litter. Similar to NH3, PLT-treated litter was more acidic compared to the control in the first half of the study but was comparable to the control from d 29 – 41.
Fig. 3. Combined mean interaction effects for broiler litter nitrogen (a), potassium (b), and phosphorus (c) content over time reported as % dry mass. LS means are provided for nitrogen content because of the significant interaction effect with litter treatment x time (P = 0.0013). a-hMeans that do not share a letter are significant at P ≤ 0.05.
Overall, litter amendments did not impact live bird performance variables including body weight (BW), body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), or FPS (Table 2). Mortalities were not different between litter treatments (P = 0.42). Mean mortalities were 1.0, 3.5, and 1.6 for the control, BC, and PLT, respectively. These results are similar to several other studies that have examined BC and PLT as litter amendments (Nagaraj et al., 2007; Purswell et al., 2013; Davis et al., 2015; Linhoss et al., 2019). Average weights for d 42 were 3,300 g for the control, 3,193 g for BC, and 3,178 g for PLT-treated pens.
Table 2. Broiler performance data over a 42 d grow-out
| Age | Variable1 | C Mean2,3 | BC Mean3 | PLT Mean3 | SEM | P-value |
|---|---|---|---|---|---|---|
| 14 d | BW (g) | 443 | 435 | 443 | 6 | 0.5033 |
| BWG (g) | 401 | 393 | 402 | 6 | 0.4956 | |
| FI (g) | 442 | 445 | 459 | 10 | 0.4590 | |
| FCR | 1.10 | 1.13 | 1.14 | 0.02 | 0.3486 | |
| 28 d | BW (g) | 1581 | 1579 | 1564 | 20 | 0.8061 |
| BWG (g) | 1539 | 1537 | 1522 | 20 | 0.8009 | |
| FI (g) | 1982 | 1987 | 1995 | 26 | 0.9431 | |
| FCR | 1.29 | 1.29 | 1.31 | 0.01 | 0.4091 | |
| 42 d | BW (g) | 3230 | 3216 | 3217 | 59 | 0.9826 |
| BWG (g) | 3188 | 3174 | 3175 | 59 | 0.9826 | |
| FI (g) | 4658 | 4620 | 4737 | 75 | 0.5548 | |
| FCR | 1.47 | 1.50 | 1.50 | 0.01 | 0.2802 | |
| 42 d | 4FPS | 0.32 | 0.68 | 0.6 | 0.13 | 0.1155 |
| 42 d | Mortality ( %) | 1.0 | 3.5 | 1.6 | 2.7 | 0.4190 |
- 1
-
Performance variables include body weight (BW), body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), foot pad scores (FPS), and mortalities.
- 2
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Control of no litter amendment (C), biochar (BC), and poultry litter treatment (PLT) used as litter treatments.
- 3
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Values represent the LS mean of 5 replicate pens containing 44 birds/pen at placement.
- 4
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Foot pad quality was evaluated using a 3-point system that assigned lesions the following scores: 0 = no lesions, 1 = lesions < 1.5 cm, 2 = lesions > 1.5 cm
FPS showed no significant difference in foot pad lesions among treatments (P = 0.1152). Birds raised on BC-amended litter had an overall mean FPS of 0.68, followed by PLT (0.60) and the control (0.32). Studies have reported similar live performance results that found no difference in performance and paw quality for birds raised on PLT or BC (Nagaraj et al., 2007, Purswell et al., 2013; Linhoss et al., 2019). The presented results support that BC and PLT as amendments do not have an adverse effect on broiler FPS and performance.
Litter treatment and grow-out time had a significant impact on NH3 volatilization, MC, pH, and nitrogen content. It is likely the treatment and time effects on NH3 were driven by elevated readings in BC-treated chambers at d 41, and future studies will consider using multiple NH3 measuring equipment. Overall, BC addition to litter reduced MC and may be beneficial for lowering litter moisture, which can improve litter quality through reducing NH3 emissions, litter caking, and microbial growth. The application of litter amendments did not have a negative impact on bird performance.
CONCLUSIONS AND APPLICATIONS
- 1.
BC may not be suitable for reducing NH3 in commercial broiler houses.
- 2.
BC significantly lowered litter MC and may be a beneficial amendment for reducing moisture in commercial broiler litter.
- 3.
PLT and BC amendments did not significantly affect bird live performance or FPS.
- 4.
Equilibrium NH3 concentrations were not significantly different between PLT-treated litter and the control after 14 d, indicating that PLT may not perform better than non-amended litter after two weeks.
Source: Science Direct
