Short communication: Comparative gene expression analysis on the enrichment of polymorphonuclear leukocytes and gastrointestinal epithelial cells in fecal RNA from nondiarrheic neonatal dairy calves

Examining Myeloperoxidase (MPO) biomarker in the saliva of patients with Lactobacillus-associated caries in Hilla City

This study aimed to evaluate the levels of myeloperoxidase (MPO) biomarkers in the saliva of individuals with Lactobacillus spp.-related caries in Hilla City. A total of 115 samples were collected, including 90 (78.26%) from patients with severe dental caries and 25 (21.74%) from healthy subjects as a control group. The age range was between 20 and 45 years, with a mean age of 33.76±2.01 for patients with severe dental caries and 24.15±0.44 for healthy subjects. Female participants constituted the majority of the study sample, with 77 (85.5%) females and 13 (14.5%) males. Pathogenic bacteria were isolated and identified using gram staining, biochemical tests, and the VITEK 2 compact system. Of the 90 clinical samples, 65 (72.2%) showed positive bacterial culture, while 25 (27.7%) samples had no bacterial growth. Lactobacillus spp. accounted for 25/65 (38.4%) of the total isolates, making it the predominant etiological agent compared to other types of bacteria, constituting 40/65 (61.5%). There was a significant decrease (p≤0.05) in myeloperoxidase levels in patients with severe dental caries and positive Lactobacillus culture compared to the control group.

Transcriptional changes detected in fecal RNA from neonatal dairy calves of different breeds following gastrointestinal disease of varying severity

Gastrointestinal (GI) disease is a major health concern in preweaned dairy calves. The objective of this fixed cohort study was to use RNA isolated from preweaned Holstein and Jersey heifer calf feces to study the molecular adaptations to variable clinical GI disease. The study was conducted on a commercial calf ranch in the western U.S. Enrolled calves were assessed twice daily for variations in demeanor, milk intake, and hydration. Fecal consistency scores were recorded at enrollment (day 1), and on the day (day 10) that a fecal sample was collected for differential gene expression (DGE). Calves with diarrhea on either day were classified as having either uncomplicated, localized GI disease (scours), or systemic GI disease (systemic enteritis). Eighty-four calves' fecal RNA was evaluated for DGE, of which 33 calves (n = 20 Holstein; n = 13 Jersey) were consistently healthy. The remaining 51 calves (n = 23 Holstein; n = 28 Jersey) experienced varying severity of GI disease during the sampling window. Genes of interest were related to the inflammatory response (i.e., IFNG, NFKB1, NOD2, TLR2, and TLR4) and cell membrane or cytoplasmic transport (i.e., AQP3, FABP2, KRT8 and SLC5A1). Breed-specific findings indicated that AQP3, IFNG, and TLR4 were upregulated in Holsteins with systemic enteritis, whereas KRT8 was downregulated in systemically affected Jerseys. Holsteins did not appear affected by scours aside from a tendency for DGE of toll-like receptors (TLRs) on the day of diarrhea. However, Jersey calves consistently demonstrated a tendency to upregulate IFNG, NFKB1, and TLR4 when affected with either scours or systemic enteritis. These findings were more pronounced in systemically affected Jersey calves and were observed as a delayed response to both scours and systemic enteritis. These findings support previous observations suggesting that Holstein calves may be better equipped than Jersey calves to rapidly fight pathogen invasion.

Early Life Fecal Microbiota Transplantation in Neonatal Dairy Calves Promotes Growth Performance and Alleviates Inflammation and Oxidative Stress during Weaning

This study aimed to evaluate the effects of early life fecal microbiota transplantation (FMT) on the health and performance of neonatal dairy calves. The donor was selected based on health and production records and fecal material testing negative for infectious pathogens. Sixteen healthy newborn Holstein calves were randomized to either a baseline nutritional program (CON) or 1×/d inoculations with 25 g of fecal donor material (FMT) mixed in the milk replacer (n = 8/TRT) from 8 to 12 days of age. Blood and fecal samples were collected weekly, and calves were weaned at 7 weeks of age. A TRT × Week interaction was observed in haptoglobin, which was reflected in a positive quadratic effect in FMT calves but not in CON. A trend for a TRT × Week interaction was observed in the liver function biomarker paraoxonase, which resulted in greater paraoxonase in FMT calves than CON at three weeks of age. Fecal microbial community analysis revealed a significant increase in the alpha-diversity between week 1 and week 5 for the FMT calves. These results suggest that early life FMT in neonatal calves has positive effects in mediating the inflammatory response and gut microbial maturation.

Short communication: Molecular markers for epithelial cells across gastrointestinal tissues and fecal RNA in preweaning dairy calves

The objective of this study was to compare the transcription of gene markers for gastrointestinal (GI) epithelial cells, including fatty acid binding protein 2 (FABP2) and cytokeratin 8 (KRT8), and tight junction complex genes (TJP1, CLDN1, CLDN4) in fecal RNA against several GI tract tissue sections in dairy calves. Eight healthy Jersey calves were euthanized at 5 wk of age, and postmortem samples were collected from rumen, duodenum, jejunum, ileum, large intestine, cecum, and feces for total RNA isolation. Tissues and fecal samples were immediately frozen in liquid nitrogen until RNA isolation. A real-time quantitative PCR analysis was performed using a single standard curve composited of equal amounts of all samples, including cDNA from fecal and GI tract tissues. The mRNA expression of the tight junctions TJP1, CLDN1, and CLDN4 was greater in fecal RNA compared with lower GI tract tissues (i.e., duodenum, jejunum, ileum, large intestine, and cecum). Similar to fecal RNA, rumen tissue had greater expression of tight junctions CLDN1 and CLDN4 than lower GI tract tissues. Similarly, rumen tissue had greater expression of TPJ1 than all lower GI tract tissues except duodenum. The expression of TJP1 and CLDN4 was greater in fecal RNA than in rumen tissue; in contrast, CLDN1 mRNA expression was greater in rumen tissue than in the fecal RNA. The expression of FABP2 was greater in duodenum in comparison to all tissue except ileum. The mRNA expression of FABP2 in fecal samples was similar to jejunum and ileum. The expression of KRT8 in fecal samples was similar to duodenum, large intestine, and cecum. The fecal RNA had a greater expression of KRT8 in comparison to jejunum and ileum. The rumen tissue had the lowest mRNA expression of KRT8. The expression levels of FABP2, KRT8, and tight junction genes observed in fecal transcripts suggest that a considerable amount of RNA derived from GI tract epithelial cells can be detected in fecal RNA, which is in agreement with previous data in neonatal dairy calves and other biological models including humans, rodents, and primates. The greater expression of tight junctions in fecal RNA in comparison to sections of the low GI remains to be understood, and due to the importance of tight junctions in GI physiology, further clarification of this effect is warranted. The similarities in mRNA expression of FABP2 and KRT8 between fecal RNA and intestinal sections add up to the accumulating evidence that fecal RNA can be used to investigate molecular alterations in the GI tract of neonatal dairy calves. Further research in this area should include high-throughput transcriptomic analysis via RNA-seq to uncover novel molecular markers for specific sections of the GI tract of neonates.

Gut health, stress, and immunity in neonatal dairy calves: the host side of host-pathogen interactions

The cumulative evidence that perinatal events have long-lasting ripple effects through the life of livestock animals should impact future nutritional and management recommendations at the farm level. The implications of fetal programming due to malnutrition, including neonatal survival and lower birth weights, have been characterized, particularly during early and mid-gestation, when placental and early fetal stages are being developed. The accelerated fetal growth during late pregnancy has been known for some time, while the impact of maternal stressors during this time on fetal development and by extent its postnatal repercussions on health and performance are still being defined. Maternal stressors during late pregnancy cannot only influence colostrogenesis but also compromise adequate intestinal development in the fetus, thus, that further limits the newborn's ability to absorb nutrients, bioactive compounds, and immunity (i.e., immunoglobulins, cytokines, and immune cells) from colostrum. These negative effects set the newborn calf to a challenging start in life by compromising passive immunity and intestinal maturation needed to establish a mature postnatal mucosal immune system while needing to digest and absorb nutrients in milk or milk replacer. Besides the dense-nutrient content and immunity in colostrum, it contains bioactive compounds such as growth factors, hormones, and cholesterol as well as molecular signals or instructions [e.g., microRNAs (miRNAs) and long non-coding RNAs (lncRNAs)] transferred from mother to offspring with the aim to influence postnatal gut maturation. The recent change in paradigm regarding prenatal materno-fetal microbiota inoculation and likely the presence of microbiota in the developing fetus intestine needs to be addressed in future research in ruminants. There still much to know on what prenatal or postnatal factors may predispose neonates to become susceptible to enteropathogens (e.g., enterotoxigenic Escherichia coli), causing diarrhea. From the host-side of this host-pathogen interaction, molecular data such as fecal RNA could, over time, help fill those gaps in knowledge. In addition, merging this novel fecal RNA approach with more established microbiome techniques can provide a more holistic picture of an enteropathogenesis and potentially uncover control points that can be addressed through management or nutrition at the farm level to minimize preweaning morbidity and mortality.