Davide Santori

The bioconversion of aquaculture sludge using Hermetia illucens larvae represents a promising strategy for sustainable waste management; however, the physiological impact of such complex matrices on the insects remains poorly understood. This study investigated the temporal dynamics of the cellular stress response (heat shock protein 70, HSP70) and metabolic vigor (vitellogenin, VTG) in relation to the functional antimicrobial activity of the hemolymph against the fish pathogen Aeromonas salmonicida. Larvae were exposed to a standard control diet, a 50% sludge blend, and 100% undiluted sludge. Our results show an immediate antimicrobial activation, resulting in the complete inhibition of bacterial viability within 4 h (T1) of exposure to the 100% sludge substrate. Conversely, molecular analysis revealed a significant transcriptional downregulation of VTG by 24 h (T2) across sludge-exposed groups. In the 100% sludge cohort, this metabolic crash coincided with a delayed upregulation of HSP70 and a 15% mortality rate. These findings suggest a potential physiological resource reallocation, where acute immune activation and cytoprotective mechanisms suppress anabolic pathways, indicating that while complex waste streams can boost acute immunological defenses, the severe subchronic metabolic costs establish strict biological limits for their acute utilization.

Hermetia illucens, the black soldier fly, is a common and widespread fly of the family Stratiomyidae. Its ability to grow on contaminated substrates suggests the production of antimicrobial peptides that enable its survival. This study aimed to verify the impact of direct and indirect infection with Salmonella enteritidis on the expression of defensins and cecropins in Hermetia illucens larvae. In addition to an infection with a microorganism, it was interesting to verify if the expression of peptides and the relative action of hemolymph changed in larvae subjected to mechanical stress by abdominal puncture. The peptide fraction of the hemolymph of infected larvae was tested using antibiogram and minimum inhibitory concentration tests against Salmonella enteritidis and Salmonella typhimurium. Both molecular and microbiological tests were carried out at three different time points, on larvae not subjected to any treatment (T-0), four hours after treatment (T-1), and 24 h after treatment (T-2). The results of the microbiological tests showed the antimicrobial action of the peptide fraction of the hemolymph against both S. typhimurium and S. enteritidis; for the latter one, the action was more marked. Interesting results were also found for larvae subjected only to mechanical stress by puncture. Molecular tests on the expression of defensins and cecropins were in full agreement with those obtained in the microbiological tests, with expression more pronounced in larvae infected directly with Salmonella enteritidis. Temporal and condition-specific regulation of defensins and cecropins highlights the complexity of the immune response and suggests sophisticated mechanisms by which the host fine-tunes antimicrobial peptide expression to enhance pathogen defense while preventing excessive immune activation.

Toxoplasma gondii is a zoonotic pathogen and the ingestion of tissue cysts by consumption of lamb or mutton has been identified as a possible cause of infection in humans. Many serological surveys in sheep have been performed, showing relevant serological rates; however, while the detection of antibodies indicates an exposure to T. gondii, this does not necessarily imply the presence of tissue cysts in edible tissue. The current study aims to provide further understanding on the occurrence of T. gondii in sheep muscles and the strength of correlation between serological positivity and presence of the parasite in sheep. From 349 sheep, samples (i.e., blood, heart and diaphragm) were collected and subjected to ELISA tests, real-time PCR and histological tests. Despite the high seroprevalence, T. gondii DNA was detected in the heart and/or the diaphragm from 13 out of the 349 tested sheep (3.7%); all were adults (13/191). Furthermore, the histological tests did not reveal the presence of T. gondii tissue cysts in any of the examined portions of interventricular septum. It should be considered that the likelihood of detecting genetic material of the parasite is probably influenced by the uneven distribution of the tissue cysts in the carcass as well as the methodology applied. The findings of this study support the importance of describing the uncertainty associated with the data used for risk assessment to reduce inaccurate estimation or risk overestimation.

Background: Intentional poisoning represents a serious health risk for domestic and wild animals, this phenomenon has been widespread in Italy for several years. Aim: Our study aims to examine data on animal poisonings that occurred in the province of Viterbo, Lazio region located in central Italy, from 2003 to 2017. The aim of this study is to provide data on the poisoning of animals in the province of Viterbo. Methods: A total of 1078 cases of suspected poisoning were analysed during the period under review. Of these, 761 (70.6%) were carcasses, 189 (17.6%) were baits, 107 (9.9%) were gastric contents, and 21 (1.9%) were samples of various origins. Results: A total of 631 cases (58.5%) were confirmed as involving toxic substances. Zinc phosphide (34.7%) was the most prevalent cause of poisoning, followed by metaldehyde (18.7%), a coumarin rodenticide (12.7%), other molecules were also identified with lower percentages. The animal species most frequently involved in poisoning are dogs (66.2%), followed by cats (25.5%), birds (4.9%), while wild animals, ruminants and fish represent a small percentage of animals involved. Conclusion: This phenomenon represents a significant threat to animals, humans and the environment. Therefore, it is essential to implement effective measures to combat this issue.

Background: Ruminants play an important role in economic sustenance in many developing countries. Abortion is one of the most important causes of economic losses in sheep livestock and, for this reason, it is very important to know, at an early stage, which pathogens caused abortion. Aim: The aim of the study is to obtain data about the distribution of abortifacient pathogens in the Italian regions of Latium and Tuscany, the awareness of the distribution of infectious agents causing abortion could allow the development of an appropriate vaccination and prophylaxis plan, in order to avoid major economic losses. Methods: 388 abortion were collected during 2015-2018 period. Organs, tissues and swabs were subjected to DNA extraction and then analysed with commercial q-PCR kits for the detection of the most common abortion pathogens circulating in these geographical areas. Results: The positivity in 148 abortion was 56% for Chlamydia abortus, 14% for Coxiella burnetii, 16% for Salmonella spp, 12% for Toxoplasma gondii and 2% for Neospora caninum. Interesting results were obtained for cases of abortions with co-infection of abortion pathogens. Conclusion: Diagnosing the cause of abortion remains a multifaceted process that may also include non-infectious factors such as deficiencies and toxicities. Further research is needed also to assess the role of low pathogen concentrations and co-infections in abortions of sheep.

Paratuberculosis is a chronic disease of ruminants caused by Mycobacterium avium subsp. Paratuberculosis (MAP). Since isolation of MAP type I (S) is rarely reported in Italy, our research was aimed at isolating, by an inexpensive liquid culture manual method, this type of MAP isolates. At first, we used an ELISA to point out to serologically positive samples from five flocks. Secondly, we used a fecal direct IS900-qPCR on the ELISA positive samples, in order to detect shedder animals. Feces from IS900-qPCR positive samples were inoculated in solid and liquid culture media. IS900-qPCR was further used to test the growth of MAP isolates in liquid medium, which were further confirmed by f57-qPCR and submitted to typing by specific PCR in order to identify the MAP type. Twenty-eight samples (24 fecal and four tissutal samples) were processed by culture methods, resulting in the isolation of six type I MAP field isolates. Notably, no isolates were recovered by solid media, underlining the utility of this liquid method. Few data about this type of MAP are currently available in Italy, and further analyses should be carried out in order to study the origin and epidemiology of type I strains circulating in Italy.