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Effects of dietary deoiled lecithin supplementation on apparent fatty acid digestibility and absorption in dairy cows.

J. W. McFadden

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06-23-2020

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Abstract:

T126
Effects of dietary deoiled lecithin supplementation on apparent fatty acid digestibility and absorption in dairy cows.
J. E. Rico1, A. B. P. Fontoura1, R. Gervais2, J. W. McFadden*1. 1Cornell University Ithaca, NY, 2Universit� Laval Qu�bec City, QC, Canada.

Our objective was to evaluate the effects of dietary palmitic acid (PA) and lecithin on fatty acid (FA) digestion in cows. In a split-plot Latin square design, 16 Holstein cows (160 � 7 DIM) were allocated to a main plot receiving a corn silage and alfalfa haylage-based diet with palm fat containing either moderate or high PA content at 1.75% of ration DM (MPA and HPA, respectively; BergaFat F-100 Classic or F-100 HP containing 87 or 98% PA, respectively; Berg + Schmidt, Hamburg, Germany; n = 8/group). On each palm fat diet, deoiled soy lecithin was top-dressed at 0, 0.12, 0.24, or 0.36% of ration DM in a replicated 4 � 4 Latin Square design. Following a covariate period, lecithin feeding spanned 14 d with feed and feces collected during the final 3 d of each experimental period. Feed and fecal FA were analyzed by GC-FID. Indigestible NDF was used as an internal marker to estimate fecal output and apparent FA digestibility. The statistical model included the fixed effects of PA supplement, lecithin dose, period, and their interactions as well as the random effect of cow. HPA increased 16C FA intake, relative to MPA (P = 0.02). Total and 16C FA digestibility were higher with MPA, relative to HPA (74 vs. 61% and 73 vs. 46%, respectively; P < 0.01); however, 18C FA digestibility was not modified by PA supplement. Total and 16C FA absorption were higher with MPA, relative to HPA (P = 0.01 and P = 0.09, respectively); however, 18C FA absorption was not modified by PA supplement. Lecithin dose linearly increased 18C FA intake in cows fed HPA (palm fat � lecithin, P = 0.07). Lecithin feeding did not modify total or 16C FA digestibility. Lecithin tended to cubicly affect 18C FA digestibility in cows fed MPA (palm fat � lecithin, P = 0.06). The absorption of total or 16C FA was not modified by lecithin; however, lecithin dose tended to linearly increase total FA absorption in cows fed HPA (palm fat � lecithin, P = 0.15). We conclude that increased dietary PA decreases FA digestibility and feeding unprotected deoiled soy lecithin does not modulate total or 16C FA digestibility in lactating cows.

Keywords: fatty acid digestibility, lecithin, palmitic acid.