3-Hydroxy-3-methylbutyrate administration diminishes fundectomy-induced osteopenia of the lumbar spine in pigs

Objective The aim of the study was to test the hypothesis that oral administration with 3-hydroxy-3-methylbutyrate (HMB) positively influences bone metabolism and diminishes fundectomy-induced osteopenia of the axial skeleton in pigs. The pig model was chosen because of its recognized physiologic and anatomic similarities of the gastrointestinal tract and skeletal system to those of humans. Methods Eighteen male pigs were divided into three weight-matched groups at 40 d of life. Animals from the first and second groups were subjected to experimental fundectomy and the third group was sham operated. Starting the day after the fundectomy, the first and second groups received placebo and HMB, respectively. Animals were sacrificed at the age of 8 mo to obtain L5 and L6 vertebrae for analysis. The effects of HMB administration on plasma amino acids concentrations, bone mineral density, morphology, and mechanical properties of the lumbar vertebrae were determined. Results The HMB treatment increased the weight of the vertebrae, bone mineral density, bone mineral content, total bone volume, trabecular bone mineral density, mean volumetric bone mineral density, calcium hydroxyapatite density in the trabecular and cortical bones, and plasma amino acid concentrations in the fundectomized pigs (P < 0.05). Mechanical strength of the spine, expressed by the values of ultimate force, Youngʹs modulus, ultimate stress, stiffness, and work to the ultimate force point was increased in HMB-treated pigs (P < 0.05). Conclusion HMB administration to fundectomized pigs improved plasma amino acids concentrations and diminished development of fundectomy-induced osteopenia of the axial skeleton.