Submitted to: Journal of Bone and Mineral Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 23, 1994
Publication Date: N/A
Interpretive Summary: Skeletal problems such as leg weakness is a significant problem in the poultry industry. One of the adverse results of the dramatic gains in broiler chic production has been the increased occurrence of leg problems associated with rapid body weight gains. Similar problems are current in he turkey industry. Leg weakness results in higher mortality rates and higher rates of carcass condemnation. This study was conducted to gain insight into how dietary fat source may influence bone development in chicks. The influence of dietary lipids on subsequent growth factor levels (a peptide hormone known to be involved in bone development) and bone structure was measured. It was determined that the source of dietary fat, albeit margarine, fish oil or butter, will differentially alter bone growth factor levels, resulting in different rates of bone development. The knowledge gained will allow better diet formulations so as to maximize bone development and potentially reduce the occurrence of leg problems in poultry.
This study examined the effects of dietary lipids on the fatty acid composition and insulin-like growth factor-I (IGF-I) concentrations in liver and bone, and bone histomorphometry in chicks. Day-old male broiler chicks were fed a semi-purified diet containing one of four dietary lipids: soybean oil (SBO), butter + corn oil (BC), margarine + corn oil (MAC), or menhaden oil + corn oil (MEC), at 70 g/kg of the diet for 42 days. At 21 day of age, chicks fed SBO had the highest levels of 18:2(n-6) and 20:4(n-6) in liver and cortical bone. Feeding the BC and MAC treatments resulted in greater amounts of 18:1 and total monounsaturates in liver. Plasma IGF-I increased in all chicks with time to 56 days of age. In 14-day-old chicks, the plasma levels of IGF-I were higher in those given MEC compared with those fed SBO. Concentrations of IGF-I in bone increased from 21 to 42 days in chicks fed SBO and BC. Periosteal bone formation rates, total new bone formation and intracortical porosity were highest in the tibiotarsi of chicks given BC. The changes in fatty acid profiles and bone histomorphometry, and the quantitative differences in IGF-I levels, suggest that dietary lipids modulate the fatty acid composition of bone and alter bone growth and modeling.