Do Common Marmosets (Callithrix jacchus) Use Scent to Communicate Information about Food Resources?

Many animals use olfactory cues to signal information about food resources; however, this particular use of scent has received little attention in primates. Common marmosets (Callithrix jacchus) are exudativores that gouge bark to elicit exudate production and frequently deposit scent marks at gouge holes. We conducted preliminary tests of the hypothesis that common marmosets use olfactory cues to communicate information about exudate value, with more desirable resources targeted for marking. We performed choice experiments on two captive male marmosets. The animals were presented with: (1) a urine scent-marked and unmarked food resource, and (2) a high and low value food resource (i.e., greater/lesser food volumes). Marmosets placed more scent marks on high, compared to low, value food resources. Animals also spent more time gouging, removed more bark and more frequently revisited high versus low value food resources. Lastly, scent-marked foods were gouged more often than unmarked foods. Our findings support the hypothesis that marmosets use scent marking and olfaction to convey information about food resources, although verification in a larger sample is needed. Nonetheless, the demonstrated link between food value and scent marking suggests that olfactory signals may aid marmoset foraging decisions.

Effect of soy isoflavone protein and soy lecithin on endothelial function in healthy postmenopausal women.

OBJECTIVE: To assess the effects of soy isoflavone protein concentrate and soy lecithin on endothelial function, measured as flow-mediated dilation (FMD) of the brachial artery in healthy postmenopausal women. DESIGN: This was a randomized, double-blind, placebo-controlled crossover trial with 25 participants (mean age, 61 years; body mass index, 25.46 kg/m2). The women underwent endothelial function testing at baseline and after 4 weeks of randomly assigned treatment with intervening 4-week washout periods. Treatment assignments included soy isoflavone protein (25 g/day) and soy lecithin (20 g/day), soy isoflavone protein (25 g/day) and placebo lecithin, placebo protein and soy lecithin (20 g/day), and double placebo. FMD and serum lipid levels were assessed at baseline and the end of each 4-week treatment phase. RESULTS: Twenty-two women completed the trial. No statistically significant (P > 0.05) difference was seen in FMD between treatment groups. A trend was suggested with FMD highest after treatment with soy protein plus lecithin (7.50 +/- 9.85), followed by soy protein (5.51 +/- 10.11), soy lecithin (5.35 +/- 6.13), and lowest after placebo (4.53 +/- 7.84). Soy isoflavone protein and soy lecithin significantly increased the high-density lipoprotein/low-density lipoprotein ratio (soy isoflavone protein plus soy lecithin, 0.64 +/- 0.19, P < 0.0001; soy isoflavone protein plus placebo lecithin, 0.58 +/- 0.17, P = 0.0058; placebo protein plus soy lecithin, 0.65 +/- 0.18, P < 0.0001) relative to the baseline value (0.49 +/- 0.15). CONCLUSIONS: In this sample of healthy postmenopausal women, soy isoflavone protein and soy lecithin significantly improved the lipid profile. A favorable influence on endothelial function could not be confirmed.