Effect of replacing inorganic trace minerals at lower organic levels on growth performance, blood parameters, antioxidant status, immune indexes, and fecal mineral excretion in weaned piglets.

Organic trace minerals (OTMs) have the potential to replace inorganic trace minerals (ITMs), but the degree to which the dietary levels can be reduced is not well defined. This study aimed to investigate the effect of replacing of ITMs with lower levels of OTMs on growth performance, blood parameters, antioxidant status, and immune indexes in weaned piglets. The experiment was conducted in a subtropical city in Guangdong Province in South China (subtropical climate) from July to September 2018. A total of 600 pigs with an average initial BW of 8.90 kg were allotted by gender and weight to 5 treatments with 6 replicate pens per treatment. Experimental treatments: (A) Control group (a basal diet with iron, copper, manganese, and zinc from sulfates and sodium selenite providing commercially utilized levels in China of 150, 25, 40, 150, and 0.5 mg/kg, respectively). (B) 1/2 ITM group (inorganic trace minerals providing 1/2 control group levels). (C) 1/2 OTM group (1/2 control group trace mineral levels with manganese, iron, zinc, and selenium from Sel-Plex® and Cu from Bioplex®). (D) 1/3 ITM group (1/3 control group trace mineral levels from inorganic forms). (E) 1/3 OTM group (1/3 control group trace mineral levels from organic forms). The results suggest no significant effects of trace mineral sources or levels, on average daily gain (ADG) and average daily feed intake (ADFI) among different treatments during the entire experiment. The level of zinc in serum was significantly decreased in the 1/3 ITM group. The 1/3 OTM group had a significantly higher (P < 0.05) immunoglobulin G (IgG) level in serum. Fecal mineral excretion decreased significantly (P < 0.05) when decreased dietary levels of trace minerals were included at 1/2 and 1/3 levels regardless of sources. Fecal concentrations of zinc excretion were lower (P < 0.05) with 1/2 OTM supplementation than 1/2 ITMs. The present study shows that replacing high doses of ITMs with low concentrations (1/3) of OTMs does not adversely affect the growth performance of piglets. At low levels, total replacement of ITMs with OTMs improved IgG and reduced fecal excretion of copper, zinc, iron, and manganese, thereby mitigating environmental pollution.

Kinetic changes in virology, specific antibody response and imaging during the clinical course of COVID-19: a descriptive study.

BACKGROUND: To explore the kinetic changes in virology, specific antibody response and imaging during the clinical course of COVID-19. METHODS: This observational study enrolled 20 patients with COVID-19, who were hospitalized between January 20-April 6, 2020, in the two COVID-19 designated hospitals of Zhoushan, Zhejiang and Rushan, Shandong, China, The laboratory findings, imaging, serum response to viral infection, and viral RNA level in the throat and stool samples were assessed from onset to recovery phase in patients with COVID-19. RESULTS: SARS-COV-2 RNA was positive as early as day four. It remained positive until day 55 post-onset in the sputum-throat swabs and became negative in most cases (55%) within 14 days after onset. Lymphocytopenia occurred in 40% (8/20) of patients during the peak infection period and returned to normal at week five. The most severe inflammation in the lungs appeared in week 2 or 3 after onset, and this was completely absorbed between week 6 and 8 in 85.7% of patients. All patients had detectable antibodies to the receptor binding domain (RBD), and 95% of these patients had IgG to viral N proteins. The antibody titer peaked at week four. Anti-S IgM was positive in 7 of 20 patients after week three. CONCLUSIONS: All COVID-19 patients in this study were self-limiting and recovered well though it may take as long as 6-8 weeks. Our findings on the kinetic changes in imaging, serum response to viral infection and viral RNA level may help understand pathogenesis and define clinical course of COVID-19.