RIcheson , John TRIcheson , John T2022-10-282022-10-282022-082022-08-01August 202https://hdl.handle.net/11310/4627The objective of this study was to determine the effects of methionine supplementation with MetaSmart before lipopolysaccharide (LPS) challenge on inflammatory biomarkers in beef cattle. Cattle (n = 65; 295.8 ± 46.5 kg BW) were randomized to three treatment groups: L0 (n=21) received 0 g of MetaSmart/animal/d, L1 (n=22) received 10 g of MetaSmart/animal/d, and L2 (n=22) received 20 g of MetaSmart/animal/d. The supplementation period consisted of 44 d before relocation for the LPS challenge period. On d 35, the cattle were weighed to determine performance and assist in selecting the cattle for LPS challenge. Temperament, body weight, and treatment history were considered in the selection of 32 cattle (n = 10 for L0 and n=11 for L1 and L2) for the LPS challenge. On d 42, steers were challenged i.v. with LPS (0.25 µg/kg BW). Four blood samples from each animal were taken -2, 0, 2, 4, 6, 8, 10, 12, 18, 24, 36, and 48 h relative to the LPS challenge at h 0. The first sample was used to measure complete blood count. A second sample was used for plasma isolation to measure amino acid concentration. The third sample was used to determine serum variables that were analyzed for cortisol, cytokines, haptoglobin, serum amyloid A, and non-esterified fatty acid concentrations. The fourth sample was processed for plasma to measure oxidative stress parameters. During the initial 35 d feeding period, there was no difference in DMI (P = 0.75) or ADG (P = 0.97). A tendency (P = 0.09) was observed for gain:feed; L2 had a greater gain:feed than L0 (P = 0.04). Time affected (P < 0.01) rectal temperature, water intake, sickness scores, cortisol, acute phase proteins, hematology parameters, serum chemistry, and cytokines, which illustrate LPS challenge efficacy. There was a treatment x time interaction (P < 0.01) for rectal temperature. Specially, L2 had greater rectal temperature than L0 (P < 0.01) and L1 (P < 0.01) at h 3. At h 4, L2 continued to have a greater rectal temperature than L1 (P = 0.04) but only tended to have a greater temperature than L0 (P =0.08). At h 17, L2 had a greater rectal temperature than L1 (P = 0.04). For h 18 (P = 0.05) and 19 (P =0.07), L2 had a greater rectal temperature than L1. Water intake volume was not different (P = 0.14), but there was a treatment difference observed in drinking bouts (P < 0.01), where the L1 and L2 steers had more drinking bouts per h than L0. Serum haptoglobin (P = 0.80) and serum amyloid A (P = 0.65) concentration did not differ between treatments. A treatment x time interaction was observed (P = 0.02) for total white blood cells such that L0 had a greater (P < 0.01) concentration than L1 at h -2 and 0. A treatment x time interaction existed for the change in white blood cells (P = 0.04). With the L0 group having more negative change than L1 and L2 from h 2 to h 12. Alkaline phosphatase had a treatment x time interaction (P < 0.01), and there was a treatment effect for change in alkaline phosphatase relative to time 0 h, with L0 having a greater change than the L1 group (P = 0.04). Calcium concentrations differed (P = 0.01), being less in the L0 group compared to the L1 and L2 treatment groups. There was a treatment x time interaction for sodium concentration (P < 0.01). The basal sodium concentrations (h -2 and 0) were greater for the L2 and L1 treatment groups compared to L0 and this occurred again at h 24. Total protein had a treatment x time interaction (P < 0.01). Specifically, at h -2, L2 cattle had greater total protein than L1 (P < 0.01), and L1 had a greater total protein than L0 (P = 0.02). There was a treatment difference between L1 and L2 compared to L0 for albumin (P = 0.04). No difference was observed in globulin concentration (P = 0.36), non-esterified fatty acids (P = 0.53), tumor necrosis factor-alpha (P = 0.87), interferon-gamma (P = 0.26), interferon-alpha a (P =0.37), interleukin 13 (P = 0.32), interleukin 1 alpha (P = 0.32), interleukin 1 F5 (P = 0.41), interleukin 21 (P = 0.37), interferon-gamma inducible protein 10 (P = 0.26), and monokine induced by interferon-gamma (P = 0.30). The L0 treatment had a greater macrophage inflammatory protein-1 beta concentration than L1 and L2 (P = 0.01). These data suggest that methionine supplementation had immunomodulatory effects in beef cattle that may improve pathogen responses, but further research is needed to determine health and performance responses in the production setting.application/pdfAgriculture, Animal Culture and NutritionThesis2022-10-28