Feeding and digestive responses to fatty acid intake in two South American passerines with different food habits

Abstract

Specific fatty acids (FA) such as unsaturated (UFA) and saturated (SFA) fatty acids contained in foods are key factors in the nutritional ecology of birds. By means of a field and experimental approach, we evaluated the effect of diet on the activity of three esterases involved in FA hydrolysis; carboxylesterase (CE: 4-NPA-CE and a-NA-CE) and butyrylcholinesterase, in two South American passerines: the omnivorous rufous-collared sparrow (Zonotrichia capensis) and the granivorous common diuca-finch (Diuca diuca). The activity of the three esterases was measured in the intestines of freshly caught individuals over two distinct seasons and also after a chronic intake of a UFA-rich or SFA-rich diet in the laboratory. In turn, we assessed the feeding responses of the birds choosing amongst diets contrasting in the kind of specific FA (UFA- vs. SFA-treated diets). During summer, field CE activities (4-NPA-CE and a-NA-CE) in the small intestine were higher in the rufous-collared sparrow (25.3 ± 3.3 and 81.4 ± 10.8 µmol min(-1) g tissue(-1), respectively) than in the common diuca-finch (10.0 ± 3.0 and 33.9 ± 13.1 µmol min(-1) g tissue(-1), respectively). Two hour feeding trial test indicated that both species exhibited a clear preference for UFA-treated diets. On average, the rufous-collared sparrow consumed 0.46 g 2 h(-1) of UFA-rich diets and 0.12 g 2 h(-1) of SFA-rich diets. In turn, the consumption pattern of the common diuca-finch averaged 0.73 and 0.16 g 2 h(-1) for UFA-rich and SFA-rich diets, respectively. After a month of dietary acclimation to UFA-rich and SFA-rich diets, both species maintained body mass irrespective of the dietary regime. Additionally, the intestinal 4-NPA-CE activity exhibited by birds fed on a UFA-rich or SFA-rich diet was higher in the rufous-collared sparrow (39.0 ± 5.3 and 44.2 ± 7.3 µmol min(-1) g tissue(-1), respectively) than in the common diuca-finch (13.3 ± 1.9 and 11.2 ± 1.4 µmol min(-1) g tissue(-1), respectively). Finally, the intestinal a-NA-CE activity exhibited by the rufous-collared sparrow was about two times higher when consuming an UFA-rich diet. Our results suggest that the rufus-collared sparrow exhibits a greater capacity for intestinal FA hydrolysis, which would allow it to better deal with fats from different sources.

Effect of diet on carboxylesterase activity of tadpoles ( Rhinella arenarum ) exposed to chlorpyrifos

“…Similarly, an inverse relationship was observed between body size and plasma esterase activities in birds (Roy et al, 2005) and amphibians (Lajmanovich et al, 2008). Dietary lipids are also important inducers of CbE activity in mammals (van Lith et al, 1992), passerine birds (Ríos et al, 2014), and some invertebrate species (Mommsen, 1978;Prento, 1987); accordingly, this esterase activity seems to be actively involved in lipid metabolism.…”

Condition-Dependent Begging Elicits Increased Parental Investment in a Wild Bird Population

“…Peanut oil is a widely used vehicle containing high amounts of unsaturated fatty acids, namely linoleic and oleic acids. Passerines prefer diets with unsaturated fats (specifically linoleic and oleic acids), and these fatty acids are commonly found in insects (see summary in Ríos et al 2014). Control broods were fed only the peanut oil vehicle in equivalent volumes as those in the experimental group, whereas natural, unmanipulated broods were not supplemented, but had a pipette tip inserted briefly into their mouths, as in the other treatments.…”

Preliminary observations suggest Common Myna prefer lipid over protein and carbohydrate foods in a pairwise choice experiment

“…Specifically, unsaturated fatty acids may be absorbed more efficiently (Pierce et al 2004). There is a direct relationship between nutrients and taste (Roura et al 2012); however, ingestion of certain nutrients may be influenced by seasons or conditions (Ríos et al 2014). During cold conditions birds store large amounts of fats in their bodies (McWilliams et al 2002).…”