Effects of unprotected choline chloride on microbial fermentation in a dual-flow continuous culture depend on dietary neutral detergent fiber concentration
Fecha
2021-03
Tipo
artículo original
Autores
Arce Cordero, José Alberto
Monteiro, Hugo Fernando
Phillips, Hannah N.
Estes, Kari
Faciola, Antonio Pinheiro
Título de la revista
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Resumen
Choline is usually supplemented as ruminally protected choline chloride to prevent its degradation in the
rumen, but the effects of unprotected choline on ruminal fermentation are unclear. Some research indicates a
possible role of dietary fiber on microbial degradation
of choline; therefore we aimed to evaluate the effects of
unprotected choline chloride on ruminal fermentation
and to investigate whether those effects depend on dietary neutral detergent fiber (NDF) concentration. Our
hypothesis was that dietary NDF concentration would
influence choline chloride effects on microbial ruminal
fermentation. We used 8 fermentors in a duplicated 4
× 4 Latin square with a 2 × 2 factorial arrangement,
combining 2 factors: (1) dietary NDF concentration
and (2) unprotected choline chloride supplementation.
Resulting treatments are (1) 30%NDF/Ctrl [30% NDF
control diet without supplemental choline (Cho)]; (2)
30%NDF/Cho [30% NDF diet plus 1.9 g of choline ion
per kg of dry matter (DM)]; (3) 40%NDF/Ctrl (40%
NDF control diet without supplemental choline); and
(4) 40%NDF/Cho (40% NDF diet plus 1.9 g of choline
ion per kg of DM). Four 10-d periods were completed,
each consisting of 7 d for adaptation and 3 d for collection of samples for estimation of nutrient disappearance
and daily average concentrations of volatile fatty acids
and NH3-N. In addition, kinetics of pH, acetate, and
propionate were evaluated at 0, 1, 2, 4, 6, and 8 h
after morning feeding. On the last day of each period,
bacteria pellets were harvested for 15N analysis and N
metabolism. Fixed effects of dietary NDF concentration, unprotected choline chloride supplementation,
and their interaction (NDF × Cho) were tested using
the MIXED procedure of SAS version 9.4 (SAS Institute Inc., Cary, NC). Choline tended to increase total
volatile fatty acid concentrations and decreased acetate
molar proportion regardless of dietary NDF concentration, but it increased propionate molar proportion
and decreased acetate to propionate ratio only with
the 30% NDF diet. Supplementing choline decreased
NDF disappearance regardless of dietary NDF; however, organic matter disappearance tended to be re duced only when choline was added to 40% NDF. Our
data indicate that unprotected choline chloride effects
on ruminal fermentation depend on dietary NDF concentration, allowing for a greater propionate synthesis
without decreasing organic matter disappearance when
fed with a 30% NDF diet.
Descripción
La Universidad de Costa Rica apoyó el programa de doctorado de José Alberto Arce Cordero
Palabras clave
In vitro, Micronutrients, Propionate, Ruminal digestibility