Js. Rennie et al., STUDIES ON EFFECTS OF NUTRITIONAL FACTORS ON BONE-STRUCTURE AND OSTEOPOROSIS IN LAYING HENS, British Poultry Science, 38(4), 1997, pp. 417-424
1. A modern hybrid strain of laying hen (Hisex) was fed from point of
lay to 68 weeks on a control diet and diets containing oystershell, fl
uoride, 1,25-dihydroxycholecalciferol, ascorbic acid, a lower concentr
ation of phosphorus and a combination of a lower concentration of crud
e protein and higher concentration of vitamin K. Hens from a much olde
r strain (Brown Leghorn J-line) were fed on the control diet. 2. Plasm
a variables were measured during lay. End-of-lay trabecular and medull
ary bone volumes in the proximal tarsometatarsus and free thoracic ver
tebra were measured by histomorphometry. 3. The majority of Hisex hens
were considered to be osteoporotic by tile end of lay. In contrast, n
one of the J-line were osteoporotic. 4. None of the nutritional treatm
ents affected trabecular bone volumes. Medullary bone volumes were inc
reased significantly by feeding oystershell or fluoride. 5. There was
no phenotypic correlation between egg production and trabecular bone v
olume in the Hisex hens. 6. The experiment provided evidence that oste
oporosis in laying hens, as assessed by trabecular bone volumes, is no
t caused by calcium deficiency and could not be prevented by any of th
e nutritional treatments studied.