Rumen and Serum Metabolomes in Response to Endophyte-Infected Tall Fescue Seed and Isoflavone Supplementation in Beef Steers

Fescue toxicosis impacts beef cattle production via reductions in weight gain and muscle development. Isoflavone supplementation has displayed potential for mitigating these effects. The objective of the current study was to evaluate isoflavone supplementation with fescue seed consumption on rumen and serum metabolomes. Angus steers (n = 36) were allocated randomly in a 2 × 2 factorial arrangement of treatments including endophyte-infected (E+) or endophyte-free (E−) tall fescue seed, with (P+) or without (P−) isoflavones. Steers were provided a basal diet with fescue seed for 21 days, while isoflavones were orally administered daily. Following the trial, blood and rumen fluid were collected for metabolite analysis. Metabolites were extracted and then analyzed by UPLC-MS. The MAVEN program was implemented to identify metabolites for MetaboAnalyst 4.0 and SAS 9.4 statistical analysis. Seven differentially abundant metabolites were identified in serum by isoflavone treatment, and eleven metabolites in the rumen due to seed type (p \u3c 0.05). Pathways affected by treatments were related to amino acid and nucleic acid metabolism in both rumen fluid and serum (p \u3c 0.05). Therefore, metabolism was altered by fescue seed in the rumen; however, isoflavones altered metabolism systemically to potentially mitigate detrimental effects of seed and improve animal performance

Considerations and best practices in animal science 16S ribosomal RNA gene sequencing microbiome studies

Microbiome studies in animal science using 16S rRNA gene sequencing have become increasingly common in recent years as sequencing costs continue to fall and bioinformatic tools become more powerful and user-friendly. The combination of molecular biology, microbiology, microbial ecology, computer science, and bioinformatics—in addition to the traditional considerations when conducting an animal science study—makes microbiome studies sometimes intimidating due to the intersection of different fields. The objective of this review is to serve as a jumping-off point for those animal scientists less familiar with 16S rRNA gene sequencing and analyses and to bring up common issues and concerns that arise when planning an animal microbiome study from design through analysis. This review includes an overview of 16S rRNA gene sequencing, its advantages, and its limitations; experimental design considerations such as study design, sample size, sample pooling, and sample locations; wet lab considerations such as field handing, microbial cell lysis, low biomass samples, library preparation, and sequencing controls; and computational considerations such as identification of contamination, accounting for uneven sequencing depth, constructing diversity metrics, assigning taxonomy, differential abundance testing, and, finally, data availability. In addition to general considerations, we highlight some special considerations by species and sample type

The Impacts of Supplemental Protein during Development on Amino Acid Concentrations in the Uterus and Pregnancy Outcomes of Angus Heifers

Replacement heifer development is one of the most critical components in beef production. The composition of the ideal uterine environment could maximize fertility and reproductive efficiency. Our hypothesis was that protein supplementation would affect the uterine environment of beef heifers without inhibiting development or reproduction. To test the effects of dietary supplementation on these outcomes, a randomized complete block design with repeated measures was implemented. Angus heifers (n = 60) were blocked by body weight (BW) and randomly assigned to one of three supplemental protein treatment groups (10% (CON), 20% (P20), and 40% (P40)). Mixed model ANOVAs were used to determine whether protein supplementation treatments, time, and the interaction or protein supplementation, semen exposure, and the interaction influenced uterine luminal fluid (ULF) and pregnancy outcomes. Amino acids (AAs) were impacted (p p = 0.03), CC (p = 0.05), 1-MH (p = 0.001), and Orn (p = 0.03). In conclusion, protein supplementation did not affect the reproductive development via puberty attainment or the timing of conception even with alterations in growth. However, uterine AA concentrations did change throughout development and protein supplementation influenced ULF d 14 post-insemination, which may affect the conception rates

Blood parameters associated with residual feed intake in beef heifers

Abstract Blood chemistry may provide indicators to greater feed efficient cattle. As a side objective to previous research, 17 Angus heifers approximately two years old underwent a feed efficiency trial to determine residual feed intake (RFI) and identify variation in blood chemistry in beef cattle divergent in feed efficiency. Heifers were categorized as high- or low-RFI based ± 0.25 standard deviations around mean RFI. Blood samples were analyzed using an i-STAT handheld blood analyzer to measure sodium, potassium, glucose, blood urea nitrogen (BUN), creatinine, hematocrit, and hemoglobin. BUN was greater in high-RFI heifers (µ = 8.7 mg/dL) contrasted to low-RFI heifers (µ = 6.5 mg/dL; P = 0.01), whereas glucose was greater in low-RFI heifers (µ = 78.1 mg/dL) contrasted to high-RFI heifers (µ = 82.0 mg/dL; P = 0.05). No other blood chemistry parameters differed by RFI. The greater abundance of BUN in high-RFI heifers may indicate inefficient utilization of protein or mobilization of tissue protein for non-protein use. Greater blood glucose concentrations in low-RFI heifers may indicate greater utilization of energy precursors, such as volatile fatty acids, or metabolites. These data suggest there are readily measurable indicators of physiological variation in nutrient utilization; however, this warrants additional studies to explore