Effects of unprotected choline chloride on microbial fermentation in a dual-flow continuous culture depend on dietary neutral detergent fiber concentration

Six dual-flow continuous-culture fermenters (1300 mL) were used to evaluate in a 2 × 3 factorial arrangement the effects of carvacrol (CAR) and cinnamaldehyde (CIN) supplementation [0.2 g kg-1 of dietary dry matter (DM)] and the source of grain (barley vs. corn) on microbial fermentation. Inoculum was collected from four ruminally cannulated lactating Holstein cows fed a mixed diet of 50% forage and 50% concentrate (16.3% crude protein, 33.5% neutral detergent fiber, DM basis). The experimental period consisted of 10 d, with the first 6 d for adaptation to experimental treatments, and 4 d of sample collection. Fermenter pH was lower for corn- than for barley-based diets (6.14 vs. 6.27; P < 0.05). True crude protein (CP) degradation tended (P = 0.10) to be higher for barley- than for corn-based diets (47.0 vs. 41.3%). Neither CAR nor CIN altered fermentation parameters [pH, NH3-N, total volatile fatty acid (VFA) concentration, and molar proportions of individual VFA], nutrient digestibility, N metabolism, and efficiency of microbial protein synthesis. The results of this study show that at the dosage selected (0.2 g kg-1 of dietary DM), CAR and CIN had no effects on microbial fermentation, feed digestibility, and N metabolism in continuous-culture fermenters fed a barley- or corn-based diet. Key words: Essential oil compound, barley, corn, continuous-culture system

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PSX-B-10 Effect of undigested neutral detergent fiber concentration and forage inclusion rate on ruminal pH, reticular motility, and total tract permeability for finishing beef heifers

Journal of Animal Science ◽

10.1093/jas/skab235.811 ◽

2021 ◽

Vol 99 (Supplement_3) ◽

pp. 457-458

Author(s):

Murillo C Pereira ◽

Karen A Beauchemin ◽

Tim A McAllister ◽

Wenzhu Yang ◽

Joyce Van Donkersgoed ◽

...

Keyword(s):

Gastrointestinal Tract ◽

Dry Matter ◽

Latin Square ◽

Barley Grain ◽

Neutral Detergent Fiber ◽

Fiber Concentration ◽

Eating Time ◽

Ruminal Ph ◽

Contraction Duration ◽

Gastrointestinal Permeability

Abstract This study evaluated the effects of undigested neutral detergent fiber (uNDF) concentration and forage inclusion (FI) rate on dry matter (DM) intake, ruminal pH, reticular contractions, and gastrointestinal permeability for finishing beef cattle. Five ruminally cannulated Hereford′Simmental heifers (699±69.1 kg) were used in an incomplete 6×6 Latin square (26-d periods) with a 2×3 factorial treatment arrangement. Barley grain-based diets were formulated using barley silage or wheat straw to provide low or high uNDF (7.1 vs. 8.5% DM) with forage proportions of 5, 10, or 15% of dietary DM. Dry matter intake (P ≥ 0.10) and eating time (P ≥ 0.13) were not affected by uNDF, FI, or uNDF′FI. With low uNDF diets, increasing FI numerically (P = 0.02) increased rumination time (min/d); while, with high uNDF diets, rumination time increased with 5 to 10% FI, but not thereafter (P = 0.03). Mean ruminal pH was not affected by uNDF (6.17 vs. 6.19; P = 0.08), but increased with increasing FI (6.04b, 6.23a, and 6.28a; P = 0.02). Duration of ruminal pH < 5.5 was not affected by uNDF but tended (P = 0.07) to be reduced with increasing FI. High uNDF diet tended to increase the frequency of reticular contractions (1.43 vs. 1.51 contractions/min; P = 0.07) but decreased the contraction duration (13.2 vs. 14.1 sec; P = 0.04). Increasing FI increased contraction frequency (1.39b, 1.50a, and 1.53a contractions/min; P = 0.03) and tended to reduce contraction duration as forage increased from 5 to 10 and 15% (14.3, 13.1, and 13.6 sec; P = 0.07). Feeding high uNDF decreased (P = 0.05) permeability of the gastrointestinal tract based on the appearance of Cr-EDTA in urine following an intra-ruminal dose. Increasing FI tended to reduce gastrointestinal tract permeability (P = 0.06). Limited interactions indicate that uNDF and FI act independently suggesting that increasing dietary uNDF, without increasing FI rate, can stimulate frequency of reticulo-ruminal contractions and reduce gastrointestinal permeability for finishing cattle.

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