Abstract #T286
Section: Ruminant Nutrition (posters)
Session: Ruminant Nutrition II
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Exhibit Hall A
Session: Ruminant Nutrition II
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Exhibit Hall A
# T286
A meta-analysis on intestinal digestibility of long-chain fatty acids in lactating dairy cows.
Jonas de Souza*1, Heidi Leskinen2, Kevin J. Shingfield4,2, Pekka Huhtanen3, Adam L. Lock1, 1Department of Animal Science, Michigan State University, East Lansing, MI, 2Animal Genomics, Green Technology, Natural Resources Institute Finland (Luke), Jokioinen, Finland, 3Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences, Umeå, Sweden, 4Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, UK.
Key Words: fatty acids, digestibility, meta-analysis
A meta-analysis on intestinal digestibility of long-chain fatty acids in lactating dairy cows.
Jonas de Souza*1, Heidi Leskinen2, Kevin J. Shingfield4,2, Pekka Huhtanen3, Adam L. Lock1, 1Department of Animal Science, Michigan State University, East Lansing, MI, 2Animal Genomics, Green Technology, Natural Resources Institute Finland (Luke), Jokioinen, Finland, 3Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences, Umeå, Sweden, 4Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, UK.
The objective of our meta-analysis was to determine intestinal digestibilities for individual long-chain fatty acids (FA) in lactating dairy cows. Our analysis utilized individual observations (n = 79) of lactating Nordic Red dairy cows from 6 Latin square or switch-back design studies. Digesta flow measurements were conducted using omasal sampling with a triple-marker system and FA were determined in omasal and fecal samples. We estimated the intestinal digestibility of long-chain FA (16:0, 18:0, cis-9 18:1, 18:2n-6, 18:3n-3 and total FA) using a Lucas test with a regression of the omasal flow of FA (g/kg DMI) on absorbed FA (g/kg DMI); slopes indicate true digestibility and intercepts endogenous synthesis. Mixed model regressions were developed between the variables of interest taking into account experiment, period within experiment, and cow within experiment as random factors. Based on the Lucas tests, estimated intestinal digestibility coefficients were 0.78, 0.70, 0.83, 0.77, 0.75, and 0.75, for 16:0, 18:0, cis-9 18:1, 18:2n-6, 18:3n-3 and total FA, respectively (Table 1). Increasing 16:0 omasal flow (43 to 145 g/d) did not affect 16:0 digestibility, while increasing 18:0 omasal flow (36 to 1306 g/d) linearly decreased 18:0 digestibility (%) [93 ± 2.16 – 0.02 ± 0.003 × 18:0 flow (g/d), P < 0.001, R2 = 0.69]. Increasing cis-9 18:1 flow (6 to 130 g/d) increased in a quadratic manner cis-9 18:1 digestibility [56.5 ± 2.91 + 0.68 ± 0.13 × cis-9 18:1 flow (g/d) - 0.004 ± 0.0001 × cis-9 18:12 (g/d), P < 0.001, R2 = 0.45]. Our results demonstrate that 18:0 has a lower digestibility coefficient compared with 16:0 and unsaturated FA, which may be associated with lower solubility of this FA, limits in emulsification capacity as flow increases, and a larger flow compared with other FA.
Table 1. Influence of omasal flow of FA (g/Kg DMI) on absorbed FA (g/Kg DMI) estimated by mixed model regression analysis (FA= A + BX1)
| Variable | A | SE | P value | B | SE | P value | R2 |
| 16:0 | −0.28 | 0.12 | 0.08 | 0.78 | 0.021 | <0.001 | 0.97 |
| 18:0 | 2.49 | 0.87 | 0.05 | 0.70 | 0.024 | <0.001 | 0.98 |
| cis-9 18:1 | −0.15 | 0.03 | 0.01 | 0.83 | 0.014 | <0.001 | 0.99 |
| 18:2n-6 | −0.034 | 0.012 | 0.01 | 0.77 | 0.016 | <0.001 | 0.98 |
| 18:3n-3 | −0.012 | 0.004 | 0.05 | 0.75 | 0.013 | <0.001 | 0.99 |
| Total FA | 1.50 | 1.20 | 0.28 | 0.75 | 0.021 | <0.001 | 0.96 |
Key Words: fatty acids, digestibility, meta-analysis
