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This paper investigates the effect of nozzle temperature, from 180 to 260 °C, on properties of polylactic acid (PLA) samples manufactured by fused deposition modeling (FDM) technology. The main objective of this research is to determinate an optimum nozzle temperature relative to tensile, flexural and compressive properties of printed specimens. After manufacturing, the samples exhibit an amorphous structure, without crystallization effects, independently of the fabrication temperature. In order to determine the influence of printing temperature on mechanical properties, uniaxial tensile, three-point flexural and compression strength tests were carried out. The obtained results suggest that a relative low printing temperature could reduce the material flow and decrease the density of the final prototype, with a negative effect on both the quality and the mechanical properties of the pieces. If temperature increases up to 260 °C, an excess of material can be deposited, but with no significant negative effect on mechanical parameters. There is an optimum nozzle temperature interval, depending on the considered piece and test, for which mechanical values can be optimized. Taking into account all tests, a recommended extruder temperature interval may be identified as 220-240 °C. This range encompasses all mechanical parameters, avoiding the highest temperature where an excess of material was observed. For this printing temperature interval, no significant mechanical variations were appreciated, which corresponds to a stable behavior of the manufactured specimens.

Among the respiratory pathogens of birds, the Avian Metapneumovirus (aMPV) is one of the most relevant, as it is responsible for causing infections of the upper respiratory tract and may induce respiratory syndromes. aMPV is capable of affecting the reproductive system of birds, directly impacting shell quality and decreasing egg production. Consequently, this infection can cause disorders related to animal welfare and zootechnical losses. The first cases of respiratory syndromes caused by aMPV were described in the 1970s, and today six subtypes (A, B, C, D, and two more new subtypes) have been identified and are widespread in all chicken and turkey-producing countries in the world, causing enormous economic losses for the poultry industry. Conventionally, immunological techniques are used to demonstrate aMPV infection in poultry, however, the identification of aMPV through molecular techniques helped in establishing the traceability of the virus. This review compiles data on the main aMPV subtypes present in different countries; aMPV and bacteria co-infection; vaccination against aMPV and viral selective pressure, highlighting the strategies used to prevent and control respiratory disease; and addresses tools for viral diagnosis and virus genome studies aiming at improving and streamlining pathogen detection and corroborating the development of new vaccines that can effectively protect herds, preventing viral escapes.

Colibacillosis is a disease caused by Escherichia coli and remains a major concern in poultry production, as it leads to significant economic losses due to carcass condemnation and clinical symptoms. The development of antimicrobial resistance is a growing problem of worldwide concern. Lysogenic bacteriophages are effective vectors for acquiring and disseminating antibiotic resistance genes (ARGs). The aim of this study was to investigate the complete genome of Escherichia coli isolates from the femurs of Brazilian broiler chickens in order to investigate the presence of antimicrobial resistance genes associated with bacteriophages. Samples were collected between August and November 2021 from broiler batches from six Brazilian states. Through whole genome sequencing (WGS), data obtained were analyzed for the presence of antimicrobial resistance genes. Antimicrobial resistance genes against the aminoglycosides class were detected in 79.36% of the isolates; 74.6% had predicted sulfonamides resistance genes, 63.49% had predicted resistance genes against β-lactams, and 49.2% of the isolates had at least one of the tetracycline resistance genes. Among the detected genes, 27 have been described in previous studies and associated with bacteriophages. The findings of this study highlight the role of bacteriophages in the dissemination of ARGs in the poultry industry.