The role of the orexin (hypocretin) system in controlling energy homeostasis, endocrine system, and reproduction in pigs and other living organisms.

Orexins A (OXA) and B (OXB) (hypocretin 1 and 2) are neuropeptides produced in the brain and peripheral tissues. Biological activities of orexins are mediated through activation of two G-protein coupled receptors termed as orexin 1 receptor (OX1R) and orexin 2 receptor (OX1R). Orexin system (OXA, OXB, OX1R, OX2R) was implicated in controlling sleep, energy expenditure, appetite, reproduction as well as metabolism and energy homeostasis. In this review, we summarize the current knowledge regarding the role of the orexin system in controlling porcine physiology. Particularly, we review and discuss evidence indicating that in pig and other living organisms, orexins and their receptors modulate the energy homeostasis, reproduction as well as functions of peripheral tissues including the pancreas, adrenal glands, gastro-intestinal tract and adipose tissue.

Review: SARS-CoV-2 infection in farmed minks - an overview of current knowledge on occurrence, disease and epidemiology.

Coronaviruses (CoVs), which are enveloped, positive-sense RNA viruses, may cause infections in mammals and birds. Apart from the respiratory manifestations, CoVs are also responsible for infections of the gastrointestinal tract and nervous systems. Their propensity to recombine allows them to easily transmit and adapt to new hosts. The emergence of a new CoV in humans, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is attributed to a zoonotic origin, has provoked numerous studies to assess its pathogenicity for different animal species (pets, farm and wild animals). Available results indicate that numerous animal species are susceptible to infection with SARS-CoV-2. From April 2020, when the first SARS-CoV-2 infection in minks was reported in the Netherlands, to the end of January 2021, further outbreaks have been confirmed in Denmark, Italy, Spain, Sweden, the United States, Greece, France, Canada, Lithuania and Poland. It has also been established that human-to-minks and minks-to-human transmission may occur. The results obtained to date indicate that the virus was originally introduced into the minks population by humans, possibly at the start of the pandemic and had been circulating in the population for several weeks before detection. Recent data indicate that minks are highly susceptible to SARS-CoV-2 infection, but the route or routes of virus transmission between farms, other than by direct contact with infected humans, have not been identified. In minks, infection can occur in clinical and subclinical form, making it possibly difficult to detect. Therefore, minks could represent potentially dangerous, not always recognized, animal reservoir for SARS-CoV-2. The current data indicate that further studies on minks and other Mustelidae are needed to clarify whether they may be a potential reservoir for SARS-CoV-2, and if so, how and whether this can be prevented.