Nanotechnological Plastic Flooring: Implications for Broiler Chicken Performance, Health, and Carcass Quality

This study evaluated the effects of two types of plastic flooring-one with and one without nanotechnological antimicrobial additives-used as complete or partial replacements for wood shavings on broiler chicken performance, yield, meat quality, and litter microbiology over 42 days. A total of 1500 Ross 408® male broiler chicks were randomly assigned to five treatment groups: wood shavings (WS), plastic flooring (PF), a 50/50 mix of plastic flooring and wood shavings (PF + WS), plastic flooring with antimicrobial additives (PFA), and a 50/50 mix of antimicrobial plastic flooring and wood shavings (PFA + WS). This study evaluated organ biometrics (liver, heart, spleen, and gizzard), the severity of Eimeria lesions, microbiological profiles, performance indices, and meat quality. The results indicated that plastic flooring, particularly when used alone, presented challenges such as increased intestinal lesions related to coccidiosis and a higher prevalence of Salmonella. Moreover, broilers raised on plastic flooring presented worse feed conversion and lower body weights and carcass yields than those raised on wood shavings. The meat quality was also negatively affected, with plastic flooring leading to less favorable fillet characteristics. Overall, the use of plastic flooring reduced the performance and health parameters of broiler chickens.

Distribution of residence time in rotary-drum composting and implications for hygienization

Rotary drums enable rapid composting compared to static systems. Residence times (RT) of 3-5 days are commonly applied to fulfill sanitary requirements and ensure the initial stabilization of organic matter. Practically, RT distribution (RTD) implies that a portion of the feed is discharged earlier than the mean RT, which may not guarantee safe application of the end product. This study assessed RTD and other physical-chemical and biological parameters of cattle manure and green waste composted in an EcodrumTM rotary drum (∼10 m3). Two types of tracers were used: pieces of plastic tubing and lumps of raw material in which plant seeds were buried, which were packed in nylon socks. A transient-state during which less than 50 % of the drum volume was occupied was distinguished from a steady-state stage, during which the drum operated with its optimal loading of about two-thirds of its volume. Starting temperatures inside the drum were close to ambient when the drum was mostly empty and then increased up to 60-65 °C as the occupied volume approached 50 %. The two types of tracers seemed to provide complementary measurements; under steady-state conditions, actual RTs were 60 % of the mean RT for 10 % of the feed material. The viability of plant seeds which were included in tracers was somewhat dependent on the specific RT. Under transient-state conditions, even shorter RTs (relative to the mean RT) are expected, coupled with non-thermophilic conditions, reducing the likelihood of adequate destruction of pathogens.

Utilization of polyethylene sleeves with forced aeration for composting of broiler carcasses on mass depopulation events: Laboratory-scale simulations and sensitivity analyses

Composting poultry carcasses and the infected litter is considered feasible during mass depopulation events in response to disease outbreaks. We demonstrate the effect of temperature (40, 50, 60 °C) and aerobic/anaerobic conditions on the degradation of broiler carcasses and broiler litter (BL) and the elimination of pre-inoculated Avian flu and Newcastle viruses and SalmonellaInfantis (3.3 × 10^5.6 EID₅₀, 7 × 10^6.0 EID₅₀ and 2 × 10⁷ CFU g-dry matter (DM)^-1, respectively). Six broiler carcasses and BL were inoculated and treated with a water-based foam, simulating a common culling method. After 30 days of composting, both viruses were eliminated under all conditions, whileSalmonellapersisted at 40 °C under aerobic and anaerobic conditions (7.4 × 10⁵and 4.4 × 10³CFU g-DM^-1, respectively). Mass losses were 42-44, 24-26, and 18-22% (aerobic) and 18-27, 21-23, and 0-7% (anaerobic) at 40, 50, and 60 °C, respectively. In the end, the associated odors were not typical of carcasses (aerobic), or they were strong and offensive (anaerobic). Considering the observed mass losses and biomass water holding capacity, we present a sensitivity analysis of the water balance expected in composting sleeves if they are utilized on mass depopulation events. Composting of the carcasses and the BL in enclosed sleeves with forced aeration, following culling by means of water-based foam will generate excess water, depending on sleeve volumes, aeration conditions, and co-addition of absorbing materials like sawdust. No excessive moisture is expected if dry culling methods are used.

A Combined Field–Lab Approach for Assessing Salmonella Infantis Persistence in Broiler Litter in a Stockpile and Composting Sleeve

Broiler litter (BL) is often contaminated by a variety of zoonotic pathogens. This study attempts to assess the persistence of Salmonella enterica serovar Infantis (S. Infantis) in BL based on spatial and temporal variation of physicochemical properties in a stockpile and composting sleeve. A single trial of two pilot-scale setups, ~35 m3 each, included an open static pile (stockpile) and composting in a polyethylene sleeve with forced aeration. The initial water content was adjusted only for the sleeve (~50% w/w) as in a common composting practice. Both systems were monitored weekly and then biweekly during 2 months in 47–53 sampling points each on every campaign. Measurements included temperature, water content, pH, electrical conductivity (EC), gas-phase oxygen, and ammonia, and the collected data were used to construct multiple contour grid maps. Of the stockpile volume, 83, 71, and 62% did not reach the commonly required minimum temperature of 55°C for three consecutive days during the first, second, and third weeks, respectively. Oxygen levels showed a strong gradient across the stockpile, while anaerobic conditions prevailed in the core. Variation was also recorded within the sleeve, but due to the water content adjustment and active aeration, the conditions favored more intense degradation and higher temperatures. Combining the grid maps drawn in this study with decay rate constants recently published for S. Infantis in BL under 36 combinations of temperature, water content, and pH, we assessed the spatial persistence of S. Infantis in the stockpile and the sleeve. Temperature was shown as a major factor, while water content and pH had only a small effect, in the stockpile only. Co-correlations between temperature, water content, EC, and oxygen suggest that selected physicochemical properties may be sufficient for such assessments. Up to 3 weeks would be recommended to achieve 7–8 log10 reduction in Salmonella in a stockpile, while this would be fully achieved within 1 week in a sleeve. This approach of combining high-resolution spatial field sampling along with decay rates of pathogens under controlled lab conditions may improve quantitative microbial risk assessments and future regulations of manure utilization.

Spatial and temporal dynamics of microbiomes and resistomes in broiler litter stockpiles

Farmers apply broiler chicken litter to soils to enrich organic matter and provide crops with nutrients, following varying periods of stockpiling. However, litter frequently harbors fecal-derived microbial pathogens and associated antibiotic resistance genes (ARGs), and may be a source of microbial contamination of produce. We coupled a cutting-edge Loop Genomics long-read 16S rRNA amplicon-sequencing platform with high-throughput qPCR that targeted a suite of ARGs, to assess temporal (five time points over a 60-day period) and spatial (top, middle and bottom layers) microbiome and resistome dynamics in a broiler litter stockpile. We focused on potentially pathogenic species from the Enterobacteriaceae, Enterococcaceae and Staphylococcaceae families associated with food-borne disease. Bacterial diversity was significantly lower in the middle of the stockpile, where targeted pathogens were lowest and Bacillaceae were abundant. E. coli was the most abundant Enterobacteriaceae species, and high levels of the opportunistic pathogen Enterococcus faecium were detected. Correlation analyses revealed that the latter was significantly associated with aminoglycoside (aac(6′)-Ib(aka aacA4), aadA5), tetracycline (tetG), vancomycin (vanC), phenicol (floR) and MLSB (mphB) resistance genes. Staphylococcaceae were primarily non-pathogenic, but extremely low levels of the opportunistic pathogen S. aureus were detected, as was the opportunistic pathogen S. saprophyticus, which was linked to vancomycin (vanSA, vanC1), MLSB (vatE, ermB) and tetracycline (tetK) resistance genes. Collectively, we found that stockpile microbiomes and resistomes are strongly dictated by temporal fluctuations and spatial heterogeneity. Insights from this study can be exploited to improve stockpile management practice to support sustainable antimicrobial resistance mitigation policies in the future.