Dietary (n-3) and (n-6) polyunsaturates and acetylsalicylic acid alter ex vivo PGE2 biosynthesis, tissue IGF-I levels, and bone morphometry in chicks

Abstract

This study examined the effects of dietary (n-6) and (n-3) polyunsaturated fatty acids (PUFA) and acetylsalicylic acid (ASA) on bone ash content, morphometry, fatty acid composition, ex vivo PGE2 biosynthesis, tissue IGF-I concentration, and serum alkaline phosphatase (ALPase) activity in chicks. Newly hatched chicks were fed a semipurified diet containing soybean oil (S) or menhaden oil / safflower oil (M) at 90 g/kg. At 4 days of age, chicks were divided into four equal treatment groups receiving 0 mg [symbol: see text] or 500 mg [symbol: see text] of ASA/kg of diet: S[symbol: see text]ASA, M[symbol: see text]ASA, S[symbol: see text]ASA, and M[symbol: see text]ASA. Lipid and ASA treatments did not affect bone length, bone ash, or bone mineral content in chicks. Chicks fed M had increased fractional labeled trabecular surface and tissue level bone formation rates, independent of ASA treatment, compared with those given S. A significant fat x ASA interaction effect was found for trabecular bone volume, thickness, separation, and number. Chicks fed S had higher 20:4(n-6) but lower 20:5(n-3) concentrations in liver and bone compared with those given M. Ex vivo PGE2 biosynthesis was higher in liver homogenates and bone organ cultures of chicks fed S compared with the values for those given M at 17 days. ASA treatment decreased ex vivo PGE2 production in liver homogenates and bone organ cultures of chicks, independent of the dietary lipids. Chicks fed ASA had a lower concentration of IGF-I in tibiotarsal bone compared with those not given ASA at 19 days. Serum ALPase activity was higher in chicks given M compared with those fed S, but the values were reversed with ASA feeding. This study demonstrated that both dietary fat and ASA modulated bone PGE2 biosynthesis, and that (n-3) PUFA and fat x ASA interactions altered bone morphometry.

Long-chain polyunsaturated fatty acids: Selected mechanisms of action on bone

“…Watkins et al [59] have shown that feeding chicks menhaden oil (high in n-3 PUFAs) resulted in a higher serum ALP activity and an increase in the bone formation rate compared to that in chicks given soy-bean oil (high in n-6…”

“…The effect of PUFAs might be exerted via modulation and reduction of PGE 2 synthesis, reducing inflammation and affecting ALP activity [2,59].…”

Inflammation, Osteoporosis and Atherosclerosis: The Tsimtsoum Concept

“…The high concentration of ALP indicated better reabsorption of bone and moreover 1.2 w-6/w-3 ratio diets showed higher rate of bone formation. In another study [23], an increased production of PGE2 in tibia of chicks given a semipurified diet containing soya bean oil, high in w-6 fat was associated with a lower rate of bone formation compared with that of chicks fed a low dietary ratio of w-6/w-3 fatty acids. In a further study [24], rats fed with a lower dietary ratio of w-6/w-3 fat showed increased bone marrow cellularity and bone strength.…”

“…Further support for the role of polyunsaturated fatty acids in the pathogenesis of osteoporosis and hip fracture may be provided from the experimental studies [22][23][24][25]. In a experimental study [22], 15 rats were fed identical diets except that w-6/w-3 ratio differed.…”

“…However, in osteoporosis, the basic cause is that reabsorption becomes greater ahead of bone formation, resulting in a net bone loss. Diets higher inw-6/w-3 fatty acids are associated with greater PGE2 which have adverse effects [22][23][24]. Whereas low w-6/w-3 ratio diet may provide low PGE2 which stimulates bone formation by increased production of insulin like growth factor, which is a powerful growth stimulator for bone and muscle.…”