| heal.abstract |
The study aimed to characterize shifts in caecotroph microbial FA induced by different dietary digestible fibre (DF) and soybean oil (SO) contents, in fattening rabbits. Following a 2 × 2 design, diets with either a low (LDF) or high (HDF) digestible fibre content (180 and 260 g DF/kg DM, respectively) supplemented with or without 20 g of SO/kg, were fed to 12 rabbits (n = 48 in total) for a period of 77 days. At an age of 63 days, a light plastic flat collar was applied on animals for 24 h to prevent caecotrophy. Gas chromatography was used to determine the odd-numbered (ONFA), branched-chain (BCFA), hydroxy (OHFA) and other FA in freeze-dried caecotroph samples. A high dietary DF level increased ONFA (P<0.01) and OHFA (P<0.05) contents, the ONFA:BCFA (P<0.05) ratio and cyclopropane 17:0Δ weight percentage in caecotrophs, suggesting that higher numbers and (or) proportions of bacterial populations were most likely associated with those FA. SO addition increased the total FA content (P<0.001) in caecotrophs, resulting in decreased ONFA (P<0.001), BCFA (P<0.001) and OHFA (P<0.05) weight percentages, which suggests a dilution effect of the dietary derived FA. Other data, such as the increased (P<0.001) conjugated linoleic acid (CLA) for HDF diets and the significant DF by SO interactions (P<0.05) observed for vaccenic (trans11-18:1) and oleic (cis9-18:1) acid, suggest other roles for FA metabolism in the caecum. Microbial FA can potentially be used to describe dietary-induced changes in the caecum, but further studies are necessary to verify their importance in rabbit nutrition research. © 2010 Elsevier B.V. All rights reserved. |
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