Evaluating the impact of gypsum as a novel bedding material on broiler performance, foot pad health, and fear response

Flue Gas Desulfurization (FGD) gypsum is a byproduct of the coal-fired power plant process commonly used to remove sulfur dioxide emissions from the flue gas. FGD gypsum has numerous industrial, agricultural, and environmental applications. This study aimed to explore a novel approach involving the use of FGD gypsum combined with different litter treatments as bedding for broiler production. It focused on performance metrics, including adjusted feed conversion ratio (AFCR) and average body weight (BW), foot pad dermatitis (FPD), and fear response over 5 consecutive flocks. A total of 1,800 one-day-old Ross 708 chicks were randomly assigned to 24 pens (75 birds/pen), divided into 6 treatment groups (4 pens/treatment), with 5 replications and raised until 42 d old (d). Treatments were gypsum that was decaked (D), rotovated (E), and rotovated then windrowed (F) between flocks. Control treatments using pine shavings were decaked (A), rotovated (B), and windrowed postrotovating (C). AFCR, average BW, and mortality were used as a measure of production. Foot pad dermatitis scores were taken on d42 using a scale of 0 (absence), 1 (mild), and 2 (severe). Response to observer and human approach test were used to measure fear response. Data were analyzed as a 2-way ANOVA (Proc Glimmix) for the main effects of bedding type and litter treatment. Means were identified using Tukey's HSD. No effect of bedding type or litter treatment was found for AFCR, BW, or mortality. FPD scores 2 and 1, were higher with pine shavings than gypsum (P = 0.01 and P = 0.01, respectively). While FPD scores 0 were higher for gypsum than the pine shaving (P = 0.01). No difference in fear response was found among birds raised on any of the gypsum litter treatments and any of the pine shaving litter treatments. Overall, the use of gypsum as bedding results in equivalent production and fear response to pine shavings, while increasing FPD quality when compared to pine shaving.

Electrostatic particle ionization for suppressing air pollutants in cage-free layer facilities

The increasing demand for cage-free (CF) poultry farming raises concern regarding air pollutant emissions in these housing systems. Previous studies have indicated that air pollutants such as particulate matter (PM) and ammonia (NH3) pose substantial risks to the health of birds and workers. This study aimed to evaluate the efficacy of electrostatic particle ionization (EPI) technology with different lengths of ion precipitators in reducing air pollutants and investigate the relationship between PM reduction and electricity consumption. Four identical CF rooms were utilized, each accommodating 175 hens of 77 wk of age (WOA). A Latin Square Design method was employed, with 4 treatment lengths: T1 = control (0 m), T2 = 12 ft (3.7 m), T3 = 24 ft (7.3 m), and T4 = 36 ft (11.0 m), where room and WOA are considered as blocking factors. Daily PM concentrations, temperature, and humidity measurements were conducted over 24 h, while NH3 levels, litter moisture content (LMC), and ventilation were measured twice a week in each treatment room. Statistical analysis involved ANOVA, and mean comparisons were performed using the Tukey HSD method with a significance level of P ≤ 0.05. This study found that the EPI system with longer wires reduced PM2.5 concentrations (P ≤ 0.01). Treatment T2, T3, and T4 led to reductions in PM2.5 by 12.1%, 19.3%, and 31.7%, respectively, and in small particle concentrations (particle size >0.5 μm) by 18.0%, 21.1%, and 32.4%, respectively. However, no significant differences were observed for PM10 and large particles (particle size >2.5 μm) (P < 0.10), though the data suggests potential reductions in PM10 (32.7%) and large particles (33.3%) by the T4 treatment. Similarly, there was no significant impact of treatment on NH3 reduction (P = 0.712), possibly due to low NH3 concentration (<2 ppm) and low LMC (<13%) among treatment rooms. Electricity consumption was significantly related to the length of the EPI system (P ≤ 0.01), with longer lengths leading to higher consumption rates. Overall, a longer-length EPI corona pipe is recommended for better air pollutant reduction in CF housing. Further research should focus on enhancing EPI technology, assessing cost-effectiveness, and exploring combinations with other PM reduction strategies.

Ammonia emissions, impacts, and mitigation strategies for poultry production: A critical review

Confined animal feeding operations (CAFOs) are the main sources of air pollutants such as ammonia (NH₃) and greenhouse gases. Among air pollutants, NH₃ is one of the most concerned gasses in terms of air quality, environmental impacts, and manure nutrient losses. It is recommended that NH₃ concentrations in the poultry house should be controlled below 25 ppm. Otherwise, the poor air quality will impair the health and welfare of animals and their caretakers. After releasing from poultry houses, NH₃ contributes to the form of fine particulate matters in the air and acidify soil and water bodies after deposition. Therefore, understanding the emission influential factors and impacts is critical for developing mitigation strategies to protect animals' welfare and health, environment, and ecosystems. This review paper summarized the primary NH₃ emission influential factors, such as how poultry housing systems, seasonal changes, feed management, bedding materials, animal densities, and animals' activities can impact indoor air quality and emissions. A higher level of NH₃ (e.g., >25 ppm) results in lower production efficiency and poor welfare and health, e.g., respiratory disorder, less feed intake, lower growth rates or egg production, poor feed use efficiency, increased susceptibility to infectious diseases, and mortality. In addition, the egg quality (e.g., albumen height, pH, and condensation) was reduced after laying hens chronically exposed to high NH₃ levels. High NH₃ levels have detrimental effects on farm workers' health as it is a corrosive substance to eyes, skin, and respiratory tract, and thus may cause blindness, irritation (throat, nose, eyes), and lung illness. For controlling poultry house NH₃ levels and emissions, we analyzed various mitigation strategies such as litter additives, biofiltration, acid scrubber, dietary manipulation, and bedding materials. Litter additives were tested with 50% efficiency in broiler houses and 80-90% mitigation efficiency for cage-free hen litter at a higher application rate (0.9 kg m^-2). Filtration systems such as multi-stage acid scrubbers have up to 95% efficiency on NH₃ mitigation. However, cautions should be paid as mitigation strategies could be cost prohibitive for farmers, which needs assistances or subsidies from governments.

Physical Characterization of Ten Hemp Varieties to Use as Animal Bedding Material

Hemp (Cannabis sativa L.) hurds, the inner bark of the stem, are a poorly appreciated part of the plant that typically represents waste. The aim of this experiment was to describe the physical characteristics, including moisture (M), water absorption (WA), and ammonia absorption (AA), of 10 hemp varieties (Fibranova, Codimono, USO31, CS, Futura 75, Eletta Campana, Carmaleonte, Felina 32, Santhica, and Ferimon) cultivated in Italy. Samples of hemp hurds were ground to 8 mm obtaining hemp shives. Values of M, WA, and AA were determined following the official procedures. The results showed an average of 7.78%, 251.9%, and 50.0% for M, WA, and AA, respectively. Data of M and WA were similar among varieties, whereas a significant difference was found for the AA, varying from 45.0 to 55.5% for the Fibranova and Ferimon varieties, respectively. In conclusion, hemp shives have good physical characteristics, similar to other commercial bedding materials (i.e., wood shavings) but other parameters and on-farm trials will be required to make a full assessment of hemp.

Assessment of Husbandry Practices That Can Reduce the Negative Effects of Exposure to Low Ammonia Concentrations in Broiler Houses

Simple Summary

We used two commercial breeds, differing in growth rate: Fast-growing breed and slow-growing breed. We stocked these birds in two different densities. The slow-growing birds was stocked at a high density and the fast-growing birds at a high density and low density. These birds were reared under two different environmental conditions: A control room with a low concentration of ammonia and a second room with a higher concentration. We analyzed management practices such as the effect of ventilation, animal density and growth rate as management possibilities to reduce the negative effect of ammonia on production parameters.

Abstract

Ammonia is an important pollutant emitted by broiler litter that can accumulate inside farms, impairing animal health and welfare productivity. An experiment was designed to evaluate of precision husbandry practices such as the effect of ventilation, animal density and growth rate as management options to reduce the adverse effects of ammonia exposure on productive parameters in broiler houses. Two identical experimental rooms were used in this study. They were programmed to differ in ammonia concentration from day 32 of the growing period (10 and 20 ppm in Room 1 and Room 2, respectively). Three treatments were tested in each room: slow growth in high stocking density (SHD), fast growth in low density (FLD) and fast growth in high density (FHD). Animal weight, feed intake and feed conversion ratio were determined weekly. In addition, the immune status of animals was assessed by weighing the organs related to immune response as stress indicators. Increasing ventilation was effective to control ammonia concentrations. Exposure to ammonia caused no significant effect on productive parameters. However, lowering stocking density improved response to higher ammonia concentrations by lowering the feed conversion ratio. No other relevant effects of differential exposure to ammonia were found in fast-growing animals, either at high or low stocking density. The use of slow-growing breeds had no effect on production parameters. Despite having a slower growth rate, their feed conversion ratio was not different from that of fast-growing breeds. The productive performance of slow-growing animals was not affected by the differential exposure to ammonia, but the reduced spleen size would suggest an impairment of the immune system.

Recovery of E. coli From Liver and Spleen of Broiler Birds and the Effects of Induced High Ammonia Level on Haematobiochemical Parameters and Its Amelioration by Different Modifiers

The poultry sector is one of the most vibrant segments of the agriculture industry of Pakistan. In addition to different infections, ammonia (NH₃) production from litter material of broiler is the most harmful pollutant and causes serious threats for the environment. To overcome this problem, different methods are proposed assuring poultry bird’s health and production. This study was carried out to evaluate the effect of toxic levels of NH₃ on the haematology and serum proteins of broiler birds and its amelioration by using different modifiers. The recovery of Escherichia coli (E. coli) from liver and spleen of broiler birds was also carried out. A total of 100 birds were divided into 5 separate groups (groups A–D). The groups C, D and E were treated with potassium aluminium sulphate, aluminium silicate and Yucca schidigera plant extract, respectively. Blood and tissue samples were collected after slaughtering the birds at 42 days of age. This study revealed increased RBC, total leucocyte count, Hb and heterophils percentage. Serum proteins were decreased in Yucca-treated and potassium aluminium sulphate–treated groups. This study concluded that NH₃ production was reduced by the application of different modifiers, and these modifiers also neutralized the changes in blood parameters induced by NH₃.

Energy metabolism disorder mediated ammonia gas-induced autophagy via AMPK/mTOR/ULK1-Beclin1 pathway in chicken livers

Ammonia gas is a well-known environmental pollution gas, threatening human health. Ammonia gas is also one of the most harmful gases to livestock and poultry for many years. Many studies have demonstrated toxic effect of ammonia gas on animal health, such as eyes, respiratory system, and digestive system. However, the effect of ammonia gas toxicity on chicken livers and underlying molecular mechanism remains unclear. In this study, we selected chicken liver as research object and duplicated successfully ammonia gas poisoning model of chickens. 1-day-old Ross-308 broilers were randomly divided into the control group (the low ammonia gas group), and two treatment groups (the middle ammonia gas group and the high ammonia gas group) (3 replicates per group and 12 chickens per replicate). Ammonia gas concentration in the low ammonia gas group was ≤5 mg/m³ during day 1-42. Ammonia gas concentration in the middle group was set as 10 ± 0.5 mg/m³ during day 1-21, and 15 ± 0.5 mg/m³ during day 22-42). Ammonia gas concentration in the high ammonia gas group was set as 20 ± 0.5 mg/m³ during day 1-21, and 45 ± 0.5 mg/m³ during day 22-42. The ultrastructure of chicken livers was observed. The activities of four ATPases (Na⁺K⁺-ATPase, Mg⁺⁺-ATPase, Ca⁺⁺-ATPase, and Ca⁺⁺Mg⁺⁺-ATPase), the expression of twelve energy metabolism-related genes (HK1, HK2, PK, PFK, PDHX, CS, LDHA, LDHB, SDHA, SDHB, avUCP, and AMPK), as well as the expression of ten autophagy-related genes (PI3K, LC3I, LC3II, Beclin1, SQSTM1, mTOR, ULK1, ATG5, ATG12, and ATG13) were measured to explore the effect of ammonia gas on energy metabolism and autophagy in chicken livers. Our results showed that excess ammonia gas induced mitochondrial and autophagic damage in chicken liver tissue cells. Meanwhile, ATPases activities were inhibited and the expression of energy metabolism-related genes changed during ammonia gas treatment, meaning that excess ammonia gas caused energy metabolism disorder. Furthermore, ammonia gas exposure altered the expression of autophagy-related genes, suggesting that ammonia gas treatment caused autophagy in chicken livers. Moreover, ammonia gas-induced AMPK compensatory up-regulation activated autophagy process through inhibiting mTOR and promoting ULK1. In addition. there were dose-dependent and time-dependent effects on all detected indexes in ammonia gas-caused chicken liver cell damage. Taken together, AMPK/mTOR/ULK1-Beclin1 pathway participated in energy metabolism disorder-mediated autophagic injury caused by ammonia gas exposure in chicken livers.

The effect of ammonia exposure on energy metabolism and mitochondrial dynamic proteins in chicken thymus: Through oxidative stress, apoptosis, and autophagy

Ammonia (NH₃) gas is an atmospheric pollutant, produced from different sources. In poultry houses NH₃ is produced from the biological process of liter, manure, and protein composition. It has been well documented that NH₃ adversely effects the health of chickens. However, the underlying mechanism of NH₃ toxicity on chicken thymus is still unknown. Thymus is an important immune organ, which play a critical role in eliciting protective immune responses to ensure healing process and elimination of harmful stimuli. The results showed that NH₃ exposure reduced antioxidant activities and induced oxidative stress in thymus tissues. Histological observation showed normal morphology of chicken thymus in control group. In contrast, increased number of nuclear debris, vacuoles, and cristae break were seen in NH₃ affected chickens. Ultrastructural analysis indicated mitochondrial breakdown, disappearance, vacuoles, and chromatin condensation in NH₃ treated groups. The mRNA and protein expression of apoptosis related genes were significantly enhanced in the chicken thymus of NH₃ affected chickens compared to control group. Moreover, Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay results suggested that NH₃ exposure increased positive stained nuclei in the chicken thymus. Meanwhile, NH₃ exposure reduced the number of CD8⁺ T-lymphocytes, decreased the adenosine triphosphate (ATPase) activities. The mRNA and protein expression of autophagy, energy metabolism, and mitochondrial dynamics proteins were altered by NH₃ exposure. In summary, these results showed that NH₃ induced oxidative stress, apoptosis and autophagic cell death (ACD), which could be the possible causes of immune damage and structural impairment in chicken thymus.

Floor Substrate Preferences of Chickens: A Meta-Analysis

Environmental enrichment promotes sensory and motor stimulation for species-typical behaviors, which in turn enhance animal well-being. For farmed Galliformes, housing systems often limit enrichment to bedding and litter, that simultaneously act as material for dustbathing and foraging. Therefore, this meta-analysis sought to systematically review and synthesize the substrate preference test literature for Galliformes. Data based on the following four welfare-related behaviors were extracted for analysis: (1) dustbathing, (2) foraging, (3) pecking, and (4) time spent on a given substrate. Literature searches in CAB Direct, Web of Science, and Google Scholar yielded 239 articles, and hand searching yielded an additional five articles. Ten publications that used different chicken strains as test subjects, met the criteria to be included in the systematic review. The effects of bedding type, the number of days birds had access to tested substrates, enclosure area, and substrate area, on the examined behaviors were determined. We found that birds preferred dustbathing in sand and peat moss more than on any other substrates. The bedding type, size of the enclosure, and size of the substrate area affected the amount of time that birds spent on the tested substrates. When provided the choice between bedding materials, birds spent more time on sand or peat moss than on any other substrate or on no substrate. Notably, most studies did not report relevant physical or chemical characteristics of substrate that may influence birds' preferences, such as grain size, moisture content and the level of soiling. Focusing future studies on identifying substrate characteristics that influence preferences can lead to the discovery of new, practical, enriching beddings that can be easily implemented in housing systems for Galliformes.

Potential contaminants and hazards in alternative chicken bedding materials and proposed guidance levels: a review

Bedding material or litter is an important requirement of meat chicken production which can influence bird welfare, health, and food safety. A substantial increase in demand and cost of chicken bedding has stimulated interest in alternative bedding sources worldwide. However, risks arising from the use of alternative bedding materials for raising meat chickens are currently unknown. Organic chemicals, elemental, and biological contaminants, as well as physical and management hazards need to be managed in litter to protect the health of chickens and consequently that of human consumers. This requires access to information on the transfer of contaminants from litter to food to inform risk profiles and assessments to guide litter risk management. In this review, contaminants and hazards of known and potential concern in alternative bedding are described and compared with existing standards for feed. The contaminants considered in this review include organic chemical contaminants (e.g., pesticides), elemental contaminants (e.g., arsenic, cadmium, and lead), biological contaminants (phytotoxins, mycotoxins, and microorganisms), physical hazards, and management hazards. Reference is made to scientific literature for acceptable levels of the above contaminants in chicken feed that can be used for guidance by those involved in selecting and using bedding materials.

Tenacity of Enterococcus cecorum at different environmental conditions

AIMS

Our aim was to analyse the survival of Enterococcus cecorum (EC) at various temperatures, relative air humidities and on different substrates commonly existing in broiler houses.

METHODS AND RESULTS

A pathogenic EC isolate (EC14) was used to inoculate sterile litter, polyvinyl chloride (PVC) and dust samples. Incubation at 37, 25 or 15°C with either 32% relative humidity (RH) or 78% RH followed. At defined time points (0-4272 h post-inoculation), samples were examined in triplicate for the total viable count. Selected combinations were repeated for a non-pathogenic and two additional pathogenic EC strains. For EC14, the measured survival time ranged from 48 to 4272 h (178 days) depending on the substrate-humidity-temperature combination. The longevity was the highest on litter, followed by dust and then PVC. Lower temperatures facilitated its survival, lower relative air humidity favoured the survival only in combination with 25 or 15°C. All three pathogenic strains showed longer survival times (up to 432 h, 18 days) compared to the non-pathogenic EC strain (168 h, 7 days) under the same conditions.

CONCLUSIONS

Enterococcus cecorum demonstrates a high persistence in the environment especially at 15°C and 32% RH.

SIGNIFICANCE AND IMPACT OF THE STUDY

Hygiene management plans should consider the durability of EC and the risk of a carry-over to control consecutive EC outbreaks.

Ammonia-triggered apoptosis via immune function and metabolic process in the thymuses of chickens by proteomics analysis

Ammonia (NH₃), an environmental pollutant with a pungent odor, is not only an important volatile in fertilizer production and ranching, but also main basic component of haze. In present study, we found that ultrastructural changes and 3167 differentially expressed proteins (DEPs) using proteomics analysis in the thymuses of chickens exposed to NH₃ on day 42. Obtained DEPs were enriched using GO and KEGG; and 66 DEPs took part in immune function, metabolic process, and apoptosis in the thymuses of chickens treated with NH₃. 9 genes of DEPs were validated using qRT-PCR, and mRNA expression of 2 immune-related genes (CTSG and NFATC2), 3 metabolic process-related genes (APOA1, GOT1, and GOLGA3), and 4 apoptosis-related genes (PIK3CD, CTSS, CAMP, and NSD2) were consistent with DEPs in chicken thymuses. Our results indicated that excess NH₃ led to immunosuppression, metabolic disorder, and apoptosis in chicken thymuses. Present study gives a novel insight into the mechanism of NH₃ toxicity and demonstrated that immune response, metabolism process, and apoptosis were important in the mechanism of NH₃ toxicity of chicken exposure to high concentration of NH₃.

Ammonia inhalation-induced inflammation and structural impairment in the bursa of fabricius and thymus of broilers through NF-κB signaling pathway

Ammonia (NH₃) is a toxic, environmental pollutant, and irritant gas. Previous studies reported the toxic effects of NH₃ which led to inflammation in various organs of chicken. However, the exact mechanism of NH₃-induced inflammation in chicken lymphoid organs bursa of fabricius (BF) and thymus is still elusive. Thus, this study was designed to investigate NH₃-induced inflammation in chicken BF and thymus. Experimental chickens were divided into low (5.0 mg/m³), middle (10.0-15.0 mg/m³), and high (20.0-45.0 mg/m³) NH₃-treated groups. To investigate NH₃-induced inflammation in chicken's BF and thymus, histological observation, NO content and iNOS activity, inflammatory cytokine contents, and mRNA levels were performed by light microscopy, microplate spectrophotometer, ELISA assay, and qRT-PCR. The finding of the present study showed that NH₃ exposure reduced BF and thymus index, increased nitric oxide (NO) content and inducible nitric oxide synthase (iNOS) activity, inflammatory cytokine contents and mRNA levels of nuclear factor-kappa B (NF-κB), cyclooxygenase-2 (Cox-2), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), IL-10, IL-1β, IL-18, toll-like receptor 2A (TLR-2A), and iNOS. Histopathological examination revealed signs of inflammation including increased nuclear debris and vacuoles in the cortex and medulla of thymus and bursal follicles. Conclusively, our findings displayed that NH₃ exposure affects the normal function of BF and thymus and led inflammation. The data provided a new ground for NH₃-induced toxicity and risk assessment in chicken production.

miR-187-5p/apaf-1 axis was involved in oxidative stress-mediated apoptosis caused by ammonia via mitochondrial pathway in chicken livers

Ammonia (NH₃), a toxic gas, is an important cause of atmospheric haze and one of the main pollutants in air environment of poultry houses, threatening the health of human beings and poultry. However, little is known about the effect of NH₃ on liver apoptotic damage. This study aimed to investigate the mechanism of oxidative stress-mediated apoptosis caused by NH₃ in chicken livers and whether miR-187-5p/apaf-1 axis was involved in this mechanism. Here we duplicated NH₃ poisoning model of chickens for fattening to study the ultrastructure of chicken livers, apoptosis rate, oxidative stress indexes, miR-187-5p, and apoptosis-related genes. Obvious apoptotic characteristics of liver tissues exposed to excess NH₃ were observed, and the apoptosis rate increased. Excess NH₃ decreased the activities of catalase (CAT), superoxide dismutase (SOD), total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px), and increased the content of malondialdehyde (MDA), suggesting that oxidative stress occurred. miR-187-5p decreased, and apoptotic protease activating factor-1 (apaf-1) increased, indicating that excess NH₃ dysregulated miR-187-5p/apaf-1 axis. The expression of tumor protein p53 (p53), Bcl-2 associated X protein (Bax), Bcl-2 homologous antagonist/killer (Bak), Cytochrome-c (Cyt-c), Caspase-9, Caspase-8, and Caspase-3 was promoted, and the expression of B-cell lymphoma-2 (Bcl-2) was inhibited, resulting in apoptosis. Moreover, oxidative stress indexes, miR-187-5p, and apoptosis-related genes changed in dose- and time-dependent manner. Altogether, miR-187-5p/apaf-1 axis participated in oxidative stress-mediated apoptosis caused by NH₃ via mitochondrial pathway in the livers of chickens for fattening. This study may provide new ideas to study the mechanism of liver apoptotic damage induced by NH₃ exposure.

Effect of pH-lowering litter amendment on animal-based welfare indicators and litter quality in a European commercial broiler husbandry

Several studies have shown that litter moisture is a major reason for foot pad lesions (FPD) and promotes microbial growth of nitrifying bacteria. The aim of the current study was to determine the possible effects of a sodium bisulfate complex (SBS) as a litter additive on FPD, hock burn (HB), and litter parameters. Two application rates of SBS were examined in 2 experiments on a commercial farm. Two groups of about 30,000 broiler chicks each were introduced on spelt granulate spread at 700 g/m² and kept for 36 d. In the first experiment (TRT1), 250 g/m² SBS was spread on top of litter 20 h before chick placement; in the second experiment (TRT2), SBS was reduced to 150 g/m². Each experiment consisted of 1 treatment group (SBS) and a control group without treatment (CON). Both experiments were repeated once. Litter parameters (pH, percentage of dry matter), foot pad, hock condition and body weight of randomly sampled birds (n = 60 per group) were recorded weekly. Mortality rate was higher in SBS groups compared to CON groups (TRT1 2.79 vs. CON 2.03%, TRT2 2.88 vs. CON 2.27%). SBS had no effect on body weight averaged over the whole production period (P > 0.05). Incidence of FPD was significantly reduced in both groups treated with SBS compared to CON (P < 0.05), with group TRT1 showing the best results. Incidence of HB was not affected by SBS (P > 0.05) but by dry matter content (P < 0.05). At the beginning, SBS reduced litter pH to 1.7 and 2.0 in TRT1 and TRT2, respectively, compared to 6.5 and 6.7 in CON. Litter pH in TRT groups increased over time and approached pH of control groups by day 15. Results of the current study indicate that SBS treatment may be beneficial regarding foot pad health in broilers. However, further studies are needed to investigate alternative SBS application rates, and to verify the results.

Influence of sepiolite additions to different litter materials on performance and some welfare parameters of broilers and litter characteristics

The litter quality is an important factor affecting the performance, welfare and carcass quality of the broilers. Depending on the progress of the fattening duration, some materials may be added to the litter in order to keep the pH, moisture and ammonia levels in the litter under control. Sepiolite is a natural material and it has strong absorbing ability to the water. Therefore, the aim of this study was to determine the effects of sepiolite additions to different litter materials on performance and some welfare parameters of broilers and litter characteristics. A total of 288 1-d-old male broiler chicks (ROSS-308) were used. Birds were randomly allocated to 2 litters (wood shavings and rice hull) and 3 sepiolite groups (0, 25, 50%) with 6 replication, and each pen contains 8 chicks. Fattening performance, IgG, tonic immobility period, feather score, skin injures, breast burns, and footpad burns of broilers were not affected significantly by sepiolite additions to the litter. However, sepiolite addition to the litter can improve litter quality. There was no significant difference between 2 litter materials because both have same color. There were no significant interactions in examined parameters. In conclusion, addition of sepiolite at 25 and 50% levels to litter materials may be used as a litter material in the broiler production without adverse welfare and performance problem.

Performance, litter quality and gaseous odour emissions of broilers fed phytase supplemented diets

The effect of graded levels of phytase on performance, bone characteristics, excreta/litter quality and odorant emissions was examined using 720 Ross 308 male d-old broilers. A 2 × 4 factorial arrangement of treatments was employed with 6 replicates of 15 birds per pen. Factors were: diets-positive and negative control (PC, NC); phytase – 0, 500, 1,000, 1,500 FTU/kg. The PC was formulated to meet the 2014 Ross 308 nutrient specifications, whereas the NC was formulated with lower Ca (−1.4 g/kg), available P (−1.5 g/kg), Na (−0.3 g/kg), dLys (−0.2 g/kg) and MEn (−0.28 MJ/kg) equivalent to nutrient matrix values for 500 FTU/kg phytase in the starter, grower and finisher periods (i.e., downspec diet). On d 24, phytase decreased FCR by 1.6, 4.3 and 4.6 points at inclusion levels of 500, 1,000 and 1,500 FTU/kg, respectively (P < 0.01) across all diets. Phytase by diet interactions on BW gain were observed on d 24 and 35 (P < 0.01). The effect of phytase was much more pronounced in the NC diet as compared with the PC diet. On d 24, phytase increased BW gain by 37, 55 and 68 g in the PC and 127, 233 and 173 g in the NC at 500, 1,000 and 1,500 FTU/kg, respectively. Diet by phytase interactions were also observed for tibia ash, litter quality and water to feed intake ratio (P < 0.01) with higher phytase effect in NC as compared with PC. Neither diet nor phytase impacted excreta moisture content on d 18 or 21 (P > 0.05). Solid phase micro-extraction gas chromatography-mass spectrometry (SPME-GC-MS) analysis of gaseous emissions on d 39 indicated no difference in the emission of alcohols, aldehydes, ketones, volatile fatty acids and phenols between treatments (P > 0.05). The results indicate that phytase has greater benefits when formulated using nutrient matrix values as compared with adding it over the top in an already nutrient sufficient diet. The later method would be expected to increase feed costs without concomitant performance benefits.

The multidimensional causal factors of 'wet litter' in chicken-meat production

The problem of 'wet litter', which occurs primarily in grow-out sheds for meat chickens (broilers), has been recognised for nearly a century. Nevertheless, it is an increasingly important problem in contemporary chicken-meat production as wet litter and associated conditions, especially footpad dermatitis, have developed into tangible welfare issues. This is only compounded by the market demand for chicken paws and compromised bird performance. This review considers the multidimensional causal factors of wet litter. While many causal factors can be listed it is evident that the critical ones could be described as micro-environmental factors and chief amongst them is proper management of drinking systems and adequate shed ventilation. Thus, this review focuses on these environmental factors and pays less attention to issues stemming from health and nutrition. Clearly, there are times when related avian health issues of coccidiosis and necrotic enteritis cannot be overlooked and the development of efficacious vaccines for the latter disease would be advantageous. Presently, the inclusion of phytate-degrading enzymes in meat chicken diets is routine and, therefore, the implication that exogenous phytases may contribute to wet litter is given consideration. Opinion is somewhat divided as how best to counter the problem of wet litter as some see education and extension as being more beneficial than furthering research efforts. However, it may prove instructive to assess the practice of whole grain feeding in relation to litter quality and the incidence of footpad dermatitis. Additional research could investigate the relationships between dietary concentrations of key minerals and the application of exogenous enzymes with litter quality.

Odour emissions from poultry litter - A review litter properties, odour formation and odorant emissions from porous materials

Odour emissions from meat chicken sheds can at times cause odour impacts on surrounding communities. Litter is seen as the primary source of this odour. Formation and emission of odour from meat chicken litter during the grow-out period are influenced by various factors such as litter conditions, the environment, microbial activity, properties of the odorous gases and management practices. Odour emissions vary spatially and temporally. This variability has made it challenging to understand how specific litter conditions contribute to odour emissions from the litter and production sheds. Existing knowledge on odorants, odour formation mechanisms and emission processes that contribute to odour emissions from litter are reviewed. Litter moisture content and water thermodynamics (i.e. water activity, Aw) are also examined as factors that contribute to microbial odour formation, physical litter conditions and the exchange of individual odorant gases at the air-water interface. Substantial opportunities exist for future research on litter conditions and litter formation mechanisms and how these contribute to odour emissions. Closing this knowledge gap will improve management strategies that intercept and interfere with odour formation and emission processes leading to an overall reduction in the potential to cause community impacts.

Water activity of poultry litter: Relationship to moisture content during a grow-out

Poultry grown on litter floors are in contact with their own waste products. The waste material needs to be carefully managed to reduce food safety risks and to provide conditions that are comfortable and safe for the birds. Water activity (Aw) is an important thermodynamic property that has been shown to be more closely related to microbial, chemical and physical properties of natural products than moisture content. In poultry litter, Aw is relevant for understanding microbial activity; litter handling and rheological properties; and relationships between in-shed relative humidity and litter moisture content. We measured the Aw of poultry litter collected throughout a meat chicken grow-out (from fresh pine shavings bedding material to day 52) and over a range of litter moisture content (10-60%). The Aw increased non-linearly from 0.71 to 1.0, and reached a value of 0.95 when litter moisture content was only 22-33%. Accumulation of manure during the grow-out reduced Aw for the same moisture content. These results are relevant for making decisions regarding litter re-use in multiple grow-outs as well as setting targets for litter moisture content to minimise odour, microbial risks and to ensure necessary litter physical conditions are maintained during a grow-out. Methods to predict Aw in poultry litter from moisture content are proposed.

Phytotoxicity as an indicator of stability of broiler production residues

Beddings used for successive broiler lots act as substrate to absorb water and feed from the excreta and may be subsequently used as agricultural fertilizers. This study evaluated the physicochemical characteristics and the phytotoxicity of beddings used to raise five consecutive broiler lots in five aviaries. Samples were collected for beddings not used yet and for beddings used at each of the five broiler lots. Lettuce and cucumber seeds were considered as phytotoxicity bioindicators. As beddings were used for greater number of lots, N, Ca, K, Mg and P contents generally increased, but the C content decreased, the pH alkalinized and humidity was reduced (P < 0.05). The germination index for lettuce and cucumber seeds was reduced with increased bedding (P < 0.05). Beddings used for at least five broiler lots presented decreased C:N ratio and would not recommended for agricultural use due to its toxicity for both tested seeds.

Semiparametric Modeling of Daily Ammonia Levels in Naturally Ventilated Caged-Egg Facilities

Ammonia concentration (AMC) in poultry facilities varies depending on different environmental conditions and management; however, this is a relatively unexplored subject in Colombia (South America). The objective of this study was to model daily AMC variations in a naturally ventilated caged-egg facility using generalized additive models. Four sensor nodes were used to record AMC, temperature, relative humidity and wind speed on a daily basis, with 10 minute intervals for 12 weeks. The following variables were included in the model: Heat index, Wind, Hour, Location, Height of the sensor to the ground level, and Period of manure accumulation. All effects included in the model were highly significant (p<0.001). The AMC was higher during the night and early morning when the wind was not blowing (0.0 m/s) and the heat index was extreme. The average and maximum AMC were 5.94±3.83 and 31.70 ppm, respectively. Temperatures above 25°C and humidity greater than 80% increased AMC levels. In naturally ventilated caged-egg facilities the daily variations observed in AMC primarily depend on cyclic variations of the environmental conditions and are also affected by litter handling (i.e., removal of the bedding material).

Water addition, evaporation and water holding capacity of poultry litter

Litter moisture content has been related to ammonia, dust and odour emissions as well as bird health and welfare. Improved understanding of the water holding properties of poultry litter as well as water additions to litter and evaporation from litter will contribute to improved litter moisture management during the meat chicken grow-out. The purpose of this paper is to demonstrate how management and environmental conditions over the course of a grow-out affect the volume of water A) applied to litter, B) able to be stored in litter, and C) evaporated from litter on a daily basis. The same unit of measurement has been used to enable direct comparison-litres of water per square metre of poultry shed floor area, L/m(2), assuming a litter depth of 5cm. An equation was developed to estimate the amount of water added to litter from bird excretion and drinking spillage, which are sources of regular water application to the litter. Using this equation showed that water applied to litter from these sources changes over the course of a grow-out, and can be as much as 3.2L/m(2)/day. Over a 56day grow-out, the total quantity of water added to the litter was estimated to be 104L/m(2). Litter porosity, water holding capacity and water evaporation rates from litter were measured experimentally. Litter porosity decreased and water holding capacity increased over the course of a grow-out due to manure addition. Water evaporation rates at 25°C and 50% relative humidity ranged from 0.5 to 10L/m(2)/day. Evaporation rates increased with litter moisture content and air speed. Maintaining dry litter at the peak of a grow-out is likely to be challenging because evaporation rates from dry litter may be insufficient to remove the quantity of water added to the litter on a daily basis.

Feed supplementation with red seaweeds, Chondrus crispus and Sarcodiotheca gaudichaudii, affects performance, egg quality, and gut microbiota of layer hens

The aim of this study was to evaluate the effect of the inclusion of red seaweed supplementation to standard poultry diets on production performance, egg quality, intestinal histology, and cecal short-chain fatty acids in Lohmann Brown Classic laying hens. A total of 160 birds were randomly assigned to 8 treatment groups. Control hens were fed a basal layer diet; positive control hens were fed a diet containing 2% inulin; and 6 treatment groups were fed a diet containing one of the following; 0.5, 1, or 2% Chondrus crispus (CC0.5, CC1, and CC2, respectively) and one of the same 3 levels of Sarcodiotheca gaudichaudii (SG0.5, SG1, and SG2, respectively). Dietary supplementation had no significant effect on the feed intake, BW, egg production, fecal moisture content, and blood serum profile of the birds. The feed conversion ratio per gram of egg was significantly more efficient (P = 0.001) for CC2 and SG2 treatments. Moreover, SG1 supplementation increased egg yolk weight (P = 0.0035) and birds with CC1 supplementation had higher egg weight (P = 0.0006). The SG2 and CC2 groups had greater (P < 0.05) villus height and villus surface area compared with the control birds. Seaweed supplementation increased the abundance of beneficial bacteria [e.g., Bifidobacterium longum (4- to 14-fold), Streptococcus salivarius (4- to 15-fold)] and importantly reduced the prevalence of Clostridium perfringens in the gut of the chicken. Additionally, the concentrations of short-chain fatty acids, including acetic acid, propionic acid, n-butyric acid, and i-butyric acid, were significantly higher (P < 0.05) in CC and SG treatments than in the control. In conclusion, dietary supplementation using red seaweed inclusions can act as a potential prebiotic to improve performance, egg quality, and overall gut health in layer hens.

Evaluation of free water and water activity measurements as functional alternatives to total moisture content in broiler excreta and litter samples

Litter moisture contents vary greatly between and within practical poultry barns. The current experiment was designed to measure the effects of 8 different dietary characteristics on litter and excreta moisture content. Additionally, free water content and water activity of the excreta and litter were evaluated as additional quality measures. The dietary treatments consisted of nonstarch polysaccharide content (NSP; corn vs. wheat), particle size of insoluble fiber (coarse vs. finely ground oat hulls), viscosity of a nonfermentable fiber (low- and high-viscosity carboxymethyl cellulose), inclusion of a clay mineral (sepiolite), and inclusion of a laxative electrolyte (MgSO4). The 8 treatments were randomly assigned to cages within blocks, resulting in 12 replicates per treatment with 6 birds per replicate. Limited effects of the dietary treatments were noted on excreta and litter water activity, and indications were observed that this measurement is limited in high-moisture samples. Increasing dietary NSP content by feeding a corn-based diet (low NSP) compared with a wheat-based diet (high NSP) increased water intake, excreta moisture and free water, and litter moisture content. Adding insoluble fibers to the wheat-based diet reduced excreta and litter moisture content, as well as litter water activity. Fine grinding of the oat hulls diminished the effect on litter moisture and water activity. However, excreta moisture and free water content were similar when fed finely or coarsely ground oat hulls. The effects of changing viscosity and adding a clay mineral or laxative deviated from results observed in previous studies. Findings of the current experiment indicate a potential for excreta free water measurement as an additional parameter to assess excreta quality besides total moisture. The exact implication of this parameter warrants further investigation.