The effect of soybean meal (SBM) replacement with fermented SBM (FSBM) on ruminal fermentation and bacterial abundance in Holstein calves was investigated in this study. Thirty nine calves were randomized to: (1) control: 27% SBM + 0% FSBM (FSBM0, n = 13); (2) 18% SBM + 9% FSBM (FSBM9, n = 13); and (3) 13.5% SBM + 13.5% FSBM (FSBM13, n = 13). SBM contained a greater amount of large peptides containing 3 to 10 amino acids (AAs), while FSBM had a greater amount of ammonia nitrogen (NH 3-N), free AAs, and small peptides containing 2 to 3 AAs. The calves fed FSBM13 had the lowest acetic acid, NH 3-N, and the ratio of acetate to propionate, with the greatest concentration of caproic acid, valeric acid and isovaleric acid in ruminal fluid. Compared to those fed FSBM9 or FSBM13, the calves fed FSBM0 had the greatest proportion of Butyrivibrio fibrisolvens and Ruminococcus albus in rumen fluid. However, the ruminal abundance of Prevotella ruminicola in calves fed FSBM13 was greater than in calves fed FSBM0. Network analysis showed that the abundance of the Ruminococcus albus was associated with large peptides, and butyric acid was correlated with small peptide. Taken together, our findings suggest that FSBM may have the potential to boost calf performance by changing the fermentation products and the relative abundance of some members of the bacterial community in the rumen. The calf starts its life with a physically and metabolically undeveloped rumen. Calves generally experience significant changes not only in the development of their rumen, but also in the rumen bacterial composition and community 1. This, in turn, enables calves to digest dry feeds for their growth needs, impacting productivity and future milk production capacity 1,2. Fibrolytic bacteria are important for the rapid anatomical and physiological growth of rumen, as the newborn calf moves from a liquid diet (i.e., milk) to a solid diet, such as grass and hay 3. Rumen microbes are classified into various functional groups, for example cellulolytic, amylolytic and proteolytic bacteria species 4. These organisms metabolize feed components and other microbial products 5. The rumen microbial community and the functional development of the stomach are affected by diets 4. For example, when forages are fed to ruminants, Bacteroidales and Ruminococcaceae become dominant 4. On the other hand, it is known that animals fed high-concentrate diets have more Prevotella and Succinivibrionaceae in their rumen fluid 4,6-8. Therefore, diets fed to animals can alter the relative abundance of bacteria and the profile of volatile fatty acids (VFAs) in the rumen 1,4. This, in turn, affects the evolution of the early ruminal development and microbiota 9 .

Understanding the most relevant hematological/biochemical characteristics, pre-existing health conditions and complications in survivors and non-survivor will aid in predicting COVID-19 patient mortality, as well as intensive care unit (ICU) referral and death. A literature review was conducted for COVID-19 mortality in PubMed, Scopus, and various preprint servers (bioRxiv, medRxiv and SSRN), with 97 observational studies and preprints, consisting of survivor and non-survivor sub-populations. This meta/network analysis comprised 19,014 COVID-19 patients, consisting of 14,359 survivors and 4655 non-survivors. Meta and network analyses were performed using META-MAR V2.7.0 and PAST software. The study revealed that non-survivors of COVID-19 had elevated levels of gamma-glutamyl transferase and creatinine, as well as a higher number of neutrophils. Non-survivors had fewer lymphocytes and platelets, as well as lower hemoglobin and albumin concentrations. Age, hypertension, and cerebrovascular disease were shown to be the most influential risk factors among non-survivors. The most common complication among non-survivors was heart failure, followed by septic shock and respiratory failure. Platelet counts, creatinine, aspartate aminotransferase, albumin, and blood urea nitrogen levels were all linked to ICU admission. Hemoglobin levels preferred non-ICU patients. Lower levels of hemoglobin, lymphocytes, and albumin were associated with increased mortality in ICU patients. This meta-analysis showed that inexpensive and fast biochemical and hematological tests, as well as pre-existing conditions and complications, can be used to estimate the risk of mortality in COVID-19 patients.

High-protein diets contribute to an increase in urea follicular concentrations associated with decreased fertility. Urea has been shown to interfere with the epidermal growth factor (EGF)/EGFR system, which has been shown to have a beneficial effect during in vitro maturation (IVM) of oocytes. Of note, the number of cumulus-oocyte complexes (COCs) in the maturation medium can change the maturation and the developmental competence of COCs. Therefore, it was hypothesized that, the presence of urea and EGF may have a differential effect on the depletion/appearance of AAs and competence of COCs matured individually (I-IVM system) or in groups (G-IVM system). In the G-IVM system, COCs increased consumption (depletion) of AAs compared with other groups in the presence of high-level urea (40 mg/dl) + EGF (10 ng/ml). In the I-IVM system, the non-cleaved COCs depleted more AAs than the cleaved COCs, in particular in the presence of urea. The combination of urea and EGF increased the depletion of AAs in the G-IVM system. However, the EGF abrogated the urea-induced depletion of AAs by the I-IVM COCs. The use of N-acetyl-l-cysteine as an EGFR inhibitor canceled urea-induced depletion of AAs. This shows the inhibiting effect of urea over the EGF/EGFR system. In the presence of urea + EGF, COCs had a lower degree of developmental competence than control in both I- and G-IVM systems. Arginine had the best predictive power to identify highly competent COCs in the G-IVM system, while glutamine was the best predictor of the cleavage in the I-IVM system. In conclusion, this multi-level study shows that COCs matured individually or in groups may have different association with AAs metabolism. These findings provide new insights into the relationships between AA metabolism and the subsequent developmental competence of COCs.

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Upon insemination, sperm cells are exposed to components of the female reproductive tract (FRT) fluids, such as urea and epidermal growth factor (EGF). It has been shown that both urea and EGF use EGF receptor signaling and produce reactive oxygen species (ROS) that are required at certain levels for sperm capacitation and acrosome reaction. We therefore hypothesized that during bovine sperm capacitation, a high level of urea and EGF could interfere with sperm function through overproduction of ROS. High-level urea (40 mg/dl urea is equal to 18.8 mg/dl of blood urea nitrogen) significantly increased ROS production and TUNEL-positive sperm (sperm DNA fragmentation, sDF) percentage, but decreased HOS test score, progressive motility, acrosome reaction and capacitation. The EGF reversed the negative effects of urea on all sperm parameters, with the exception of ROS production and DNA fragmentation, which were higher in urea-EGF-incubated sperm than in control-sperm. The developmental competence of oocytes inseminated with urea-EGF-incubated sperm was significantly reduced compared to the control. A close association of ROS production or sDF with 0-pronuclear and sperm non-capacitation rates was found in the network analysis. In conclusion, EGF enhanced urea-reduced sperm motility; however, it failed to reduce urea-increased sperm ROS or sDF levels and to enhance subsequent oocyte competence. The data suggests that any study to improve sperm quality should be followed by a follow-up assessment of the fertilization outcome.