Jersey Steer Ruminal Papillae Histology and Nutrigenomics
Type of DegreeMaster's Thesis
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The transition from a high forage to a high concentrate diet is an important milestone for beef cattle moving from a stocker system to the feedlot. However, little is known about how this transition affects the rumen epithelial gene expression. This study assessed the effects of the transition from a high forage to a high concentrate diet as well as the transition from a high concentrate to a high forage diet on a variety of genes as well as ruminal papillae morphology in fistulated Jersey steers. In addition, the effects of using whole versus cracked corn on rumen papillae were ascertained by switching from whole corn to cracked corn 51 days after the start of the study. Jersey steers (n = 5) were fed either a high forage diet (100% forage) and transitioned to a high concentrate diet (20% forage and 80% grain) or a high concentrate diet that was transitioned to a high forage diet. Papillae from the rumen were collected for histology and RT-qPCR analysis. Histological analysis showed a relative increase in papillae length as concentrate was added to the diet in steers transitioning from a high forage to a high concentrate diet (P = 0.05). Genes related to cell membrane structure (CLDN1, CLDN4, DSG1), fatty acids metabolism (CPT1A, ACADSB), glycolysis (PFKL), ketogenesis (HMGCL, HMGCS2, ACAT1), lactate/pyruvate (LDHA), oxidative stress (NQO1), tissue growth (AKT3, EGFR, EREG, IGFBP5, IRS1), and urea cycle (SLC14A1) had a significant diet change × treatment interaction (P < 0.05). All of these changes can be considered indicators of rumen epithelial adaptation in response to changes in diet. In conclusion, these results indicate changes in the composition of the diet can alter the expression of genes which function in rumen epithelial metabolism.