title: Skeletal effect of casein and whey protein intake during catch-up growth in young male Sprague-Dawley rats.
abstract: The aim of the present study was to determine whether the type of protein ingested influences the efficiency of catch-up (CU) growth and bone quality in fast-growing male rats. Young male Sprague-Dawley rats were either fed ad libitum (controls) or subjected to 36 d of 40 % food restriction followed by 24 or 40 d of re-feeding with either standard rat chow or iso-energetic, iso-protein diets containing milk proteins - casein or whey. In terms of body weight, CU growth was incomplete in all study groups. Despite their similar food consumption, casein-re-fed rats had a significantly higher body weight and longer humerus than whey-re-fed rats in the long term. The height of the epiphyseal growth plate (EGP) in both casein and whey groups was greater than that of rats re-fed normal chow. Microcomputed tomography yielded significant differences in bone microstructure between the casein and whey groups, with the casein-re-fed animals having greater cortical thickness in both the short and long term in addition to a higher trabecular bone fraction in the short term, although this difference disappeared in the long term. Mechanical testing confirmed the greater bone strength in rats re-fed casein. Bone quality during CU growth significantly depends on the type of protein ingested. The higher EGP in the casein- and whey-re-fed rats suggests a better growth potential with milk-based diets. These results suggest that whey may lead to slower bone growth with reduced weight gain and, as such, may serve to circumvent long-term complications of CU growth.
authors.affiliation: 1Sackler Faculty of Medicine,Tel Aviv University,Tel Aviv,6997801,Israel.
authors.forename: Majdi
authors.initials: M
authors.lastname: Masarwi
authors.affiliation: 1Sackler Faculty of Medicine,Tel Aviv University,Tel Aviv,6997801,Israel.
authors.forename: Yankel
authors.initials: Y
authors.lastname: Gabet
authors.affiliation: 1Sackler Faculty of Medicine,Tel Aviv University,Tel Aviv,6997801,Israel.
authors.forename: Oleg
authors.initials: O
authors.lastname: Dolkart
authors.affiliation: 4Biomechanical Laboratory,School of Dental Medicine,Tel Aviv University,Tel Aviv,6997801,Israel.
authors.forename: Tamar
authors.initials: T
authors.lastname: Brosh
authors.affiliation: 1Sackler Faculty of Medicine,Tel Aviv University,Tel Aviv,6997801,Israel.
authors.forename: Raanan
authors.initials: R
authors.lastname: Shamir
authors.affiliation: 1Sackler Faculty of Medicine,Tel Aviv University,Tel Aviv,6997801,Israel.
authors.forename: Moshe
authors.initials: M
authors.lastname: Phillip
authors.affiliation: 1Sackler Faculty of Medicine,Tel Aviv University,Tel Aviv,6997801,Israel.
authors.forename: Galia
authors.initials: G
authors.lastname: Gat-Yablonski
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000187:drug effects; D001846:Bone Development / Q000187:drug effects*; D002364:Caseins / Q000008:administration & dosage / Q000494:pharmacology*; D006132:Growth Plate / Q000254:growth & development; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012741:Sexual Maturation; D000067816:Whey Proteins / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D002364:Caseins; D000067816:Whey Proteins
keywords: AL (ad libitum) controls fed regular chow; AVD apparent volume density; BV bone volume; Biomechanics; CU (catch-up) re-fed regular chow; Cas (casein) re-fed casein-formulated chow; Casein; Catch-up growth; Ct.Ar cortical area; EGP epiphyseal growth plate; IGF-I insulin-like growth factor-I; LT long-term; Microcomputed tomography; OC osteocalcin; RES (restriction) restricted to 40 % of daily intake of regular chow; TV total volume; Tb.Th trabecular thickness; Tt.Ar total area; Whey; Whey (whey) re-fed whey-formulated chow; µCT microcomputed tomography