Recipient Organization
KANSAS STATE UNIV
(N/A)
MANHATTAN,KS 66506
Performing Department
Animal Science & Industry
Non Technical Summary
Dr. Vieira-Netohas conducted a significant amount of research assessing mineral metabolsim in ruminants. This project will elucidate the effects of vitamin D metabolites and dietary calcium content on calcium absorption in the gastrotintestinal tract and the genes and proteins that are playing a role in this process.The data will be used to further understand calcium metabolism in ruminants, as most of the available data is provinient from monogastrics, and in addition may be usefull for the development of new strategies to improve calcium metabolism in ruminants.?
Animal Health Component
15%
Research Effort Categories
Basic
85%
Applied
15%
Developmental
(N/A)
Goals / Objectives
Objective 2: To identify and quantify molecular, cellular, and organismal signals that regulate intake, partitioning and efficient utilization of nutrients
Objective 3: To use this knowledge of feed properties and metabolic and molecular quantitative relationships to challenge and refine nutrient requirement models leading to more accurate feeding systems for dairy cattle
Project Methods
The project is a continuating of an experiment that was conduct at Texas Tech University and approved by the IACUC (ACUC#: 20082-10). Samples collected during the experiment will be analyzed at Kansas State Unvirsity.Twenty-four (n = 24) Holstein bull calves at 90 ± 1 d of age were enrolled in the experiment. Treatments were arranged as a 2 x 2 factorial with 2 levels of dietary Ca (0.21% vs. 1.00% of diet DM) and 2 amounts of 1,25-dihydroxyvitamin D3(0 vs. 50 µg) administered subcutaneously as a single injection on day 6; therefore, the 4 treatments were:Ca deficient diet + 0 µg 1,25-dihydroxyvitamin D3;Ca deficient diet + 50 µg 1,25-dihydroxyvitamin D3;Ca adequate diet + 0 µg 1,25-dihydroxyvitamin D3;Ca adequate diet + 50 µg 1,25-dihydroxyvitamin D3;Mineral Balance:On experimental d 4, 5, 6, 7, and 8, balance of Ca, Mg, and P will be evaluated by measuring intake of minerals and urinary and fecal excretions. Feed samples, calf grower and hay, will be collected on experimental d 3, 4, 5, 6, 7, and 8. Orts of individual calves will be collected on experimental d 4, 5, 6, 7, 8, and 9. Urine will be sampled every 6 h (4 samples/day) on experimental d 4, 5, 6, 7, and 8 for quantification of concentrations of creatinine, Ca, Mg, and P. Samples will be collected at 0, 6, 12, and 18 h relative to the morning feeding to represent the entire 24-h feeding cycle. Creatine will be used as maker for urinary output. The spot sample will be collected in a 20 mL vial. A composite with similar volume of all the samples collected in the 24-h feeding cycle will be made and an aliquot will be frozen and stored at -20°C for further analyses. Fecal samples will be collected every 6 h (4 samples/day) on experimental d 4, 5, 6, 7, and 8. Daily composites will be made and dried at 60°C for determination of DM, and then stored for further analyses. Indigestible NDF (iNDF at 240 h) will be used as internal marker to estimate fecal output. Concentrations of Ca, Mg, and P will be analyzed in the dietary ingredients to build the respective diets offered, individual orts, and individual fecal samples.Tissue Collection:On experimental d 9, all the calves wereeuthanized using a penetrating captive bold followed by exsanguination.Tissues collected include:Contents: ruminal, abomasum, duodenum, colon;Ruminal epithelium; Reticulum; Omasum; Abomasum;Duodenum; Jejunum; Ileum;Colon;Renal cortex; Renal medulla;Periosteum, trabecular bone, bone marrow;Liver, and lungs.Samples weresnap-frozen in triplicates (enough for mRNA and protein analysis) in liquid nitrogen and then stored in -80°C until further analysis, and samples will be stored on special media for immunohistochemistry. mRNA will be extracted from tissues collected and submitted for RNA-Seq at the Texas Tech University Core Facility at the Center for Biotechnology & Genomics.