Investigation of chromium, cerium and cobalt as markers in digesta. Rate of passage studies

Cobalamin (CBL), the biologically active form of vitamin B 12 , and its analogs, are produced by bacteria only if cobalt supply is adequate. The analogs differ generally by the nucleotide moiety of the molecule. In CBL, 5,6-dimethylbenzimidazole (5,6-DMB) is the base in the nucleotide moiety. The present study aimed to determine if a supplement of 5,6-DMB could increase utilization of dietary cobalt for synthesis of CBL and change ruminal fermentation, nutrient digestibility, omasal flow of nutrients and ruminal protozoa counts. Eight ruminally cannulated multiparous Holstein cows (mean ± standard deviation = 238 ± 21 days in milk and 736 ± 47 kg of BW) were used in a crossover design. Cows were randomly assigned to a daily supplement of a gelatin capsule containing 1.5 g of 5,6-DMB via the rumen cannula or no supplement. Each period lasted 29 days and consisted of 21 days for treatment adaptation and 8 days for data and samples collection. Five corrinoids, CBL and four cobamides were detected in the total mixed ration and the omasal digesta from both treatments. The dietary supplement of 5,6-DMB increased (P = 0.02) apparent ruminal synthesis of CBL from 14.6 to 19.6 (s.e.m. 0.8) mg/day but had no effect (P > 0.1) on apparent ruminal synthesis of the four analogs. The supplement of 5,6-DMB had no effect (P > 0.1) on milk production and composition, or on protozoal count, ruminal pH and concentrations of volatile fatty acids and ammonia nitrogen in rumen content. The supplement had also no effect (P > 0.1) on intake, omasal flow and apparent ruminal digestibility of dry matter, organic matter, NDF, ADF and nitrogenous fractions. Plasma concentration of CBL was not affected by treatments (P = 0.98). Providing a preformed part of the CBL molecule, that is, 5,6-DMB, increased by 34% the apparent ruminal synthesis of CBL by ruminal bacteria but had no effect on ruminal fermentation or protozoa count and it was not sufficient to increase plasma concentrations of the vitamin. Even though the efficiency of cobalt utilization for apparent synthesis of CBL was increased from 2.0% to 2.7% by the 5,6-DMB supplement, this improved efficiency was still very low. Further research is needed to identify the factors affecting efficiency of utilization of cobalt for synthesis of CBL by the bacterial populations in rumen.Keywords: dairy cow, vitamin B 12 , cobalt, 5,6-dimethylbenzimidazole, ruminal microflora ImplicationsUnlike other B vitamins, vitamin B 12 is not present in plants and is produced only by bacteria if cobalt supply is adequate. Therefore, dairy cows rely on synthesis of the vitamin by the bacteria present in rumen to cover their requirements. However, the proportion of cobalt used for these syntheses is low. Providing a preformed part of the vitamin B 12 molecule (5,6-dimethylbenzimidazole) increased by 34% apparent synthesis of the vitamin by ruminal bacteria but failed to increase substantially efficiency of cobalt utilization. The results highlight the lack of knowledge on nutritional factors driving ruminal pr...

Section: Methodsmentioning

confidence: 99%

Supplementing lactating dairy cows with a vitamin B12 precursor, 5,6-dimethylbenzimidazole, increases the apparent ruminal synthesis of vitamin B12

Brito

Chiquette

Stabler

et al. 2015

“…Starting at day 7, Co-EDTA (1.14 g Co/day) was dissolved in 12 l water and infused into the rumen at a constant rate (0.5 l/h). The Cr-NDF and Co-EDTA were prepared as described by Udén et al (1980); Cr-NDF was prepared from wheat straw, thoroughly washed, dried and ground to pass a 0.5-mm screen.…”

Section: Markersmentioning

confidence: 99%

Passage kinetics of concentrates in dairy cows measured with carbon stable isotopes

Warner

Dijkstra

Tamminga

et al. 2013

Fractional passage rates form a fundamental element within modern feed evaluation systems for ruminants, but knowledge on feed-specific fractional passage is largely lacking. Commonly applied tracer techniques based on externally applied markers, such as chromium-mordanted neutral detergent fibre (Cr-NDF), have been criticised for behaving differently to feed particles. This study describes the use of the carbon stable isotope ratio ( 13 C : 12 C) as an internal digesta marker to quantify the fractional passage rate of concentrates through the digestive tract of dairy cows. In a crossover study, five dairy cows were fed low (24.6%) and high (52.6%) levels of concentrates (dry matter (DM) basis) and received a pulse-dosed Cr-NDF and 13 C isotopes. The latter was administered orally by exchanging part of the dietary concentrates of low 13 C natural abundance with a pulse dose of maize bran-based concentrates of high 13 C natural abundance. Fractional passage rates from the rumen ( K 1 ) and from the large intestine ( K 2 ) were determined from faecal marker concentrations of Cr-NDF and of 13 C in the DM ( 13 C-DM), NDF ( 13 C-NDF) and neutral detergent soluble ( 13 C-NDS). No differences in K 1 estimates were found for the two concentrate levels fed but significant differences between markers ( P < 0.001) were observed. Faecal Cr-NDF excretions gave lower K 1 estimates (0.037-0.039/h) than 13 C-DM (0.054-0.056/h) and 13 C-NDF (0.061-0.063/h). The 13 C-NDS was calculated by the difference of 13 C in the DM and NDF, and K 1 values (0.039-0.043/h) were comparable to Cr-NDF. Total mean retention time was considerably higher for Cr-NDF (40.9-42.0 h) as compared to 13 C-DM and 13 C-NDF (32.0-33.5 h; P < 0.001). The accuracy of the curve fits for Cr-NDF and 13 C-DM and 13 C-NDF was overall good (mean prediction error of 9.9-13.9%). Fractional passage rate of Cr-NDF was comparable to studies where this marker was assumed to represent the fractional passage of roughages. However, K 1 estimates based on the 13 C : 12 C ratio varied considerably from studies based on external markers. Our results suggest that the use of 13 C isotopes as digesta passage markers can provide feed component-specific K 1 estimates for concentrates and provides new insight into passage kinetics of NDF from technologically treated compound feed.

“…Digesta flow entering the omasal canal was estimated using a triple marker method (France and Siddons, 1986). Indigestible NDF (iNDF), which was mainly associated with the large particle (LP) fraction (Ahvenjä rvi et al, 2003); Yb, which was concentrated in the small particle (SP) digesta phase; and Co, which marked the FP (Udé n et al, 1980) were used in combination to calculate digesta flow. The omasal sampling technique developed by Huhtanen et al (1997), as modified by Ahvenjä rvi et al (2000), was used to collect four daily samples at 2-h intervals over three Alfalfa silage quality and roasted corn consecutive days to represent the 24-h feeding cycle.…”

Section: Methodsmentioning

confidence: 99%

Effects of alfalfa silage storage structure and roasting corn on ruminal digestion and microbial CP synthesis in lactating dairy cows

Krizsan

Broderick

Promkot

et al. 2012

The objective of this experiment was to quantify the effects of unroasted or roasted ground-shelled corn (GSC), when fed with alfalfa ensiled in bag, bunker, or O 2 -limiting tower silos on ruminal digestion and microbial CP synthesis in lactating dairy cows. The roasted corn was heat-treated in a propane-fired roasting system. Alfalfa was harvested as second cutting from fields with regrowth of the same maturity. A portion of each field was allotted to each silo. The diets with 3 3 2 factorial arrangement of treatments were fed to six multiparous rumen-cannulated Holstein cows in a cyclic change-over design with five 21-day periods. Experimental diets were comparable and averaged (on dry matter (DM) basis): 410 g/kg alfalfa silage (AS), 150 g/kg corn silage, 350 g/kg GSC, 50 g/kg soybean meal, 40 g/kg roasted soybeans, 177 g/kg CP, 264 g/kg NDF and 250 g/kg starch. Nutrient flow was quantified by the omasal sampling technique with use of three markers (Co, Yb and indigestible NDF). Continuous infusion of 10% atom excess ( 15 NH 4 ) 2 SO 4 was used to label microbial CP. None of the interactions between storage structure of dietary AS and corn type were significant. DM intake was not different among dietary treatments, averaging 24.5 kg/day across diets. Means of ADF digested in the rumen for cows fed diets with AS from bag, bunker and O 2 -limiting tower silo were 2.1, 1.7 and 2.1 kg/day, respectively, and was lower in cows fed AS from the bunker silo. This response may partly be a reflection of the higher intake of ADF by cows fed AS ensiled in the O 2 -limiting tower silo compared with the bunker. There was a slightly greater supply of fermentable substrates for cows fed diets with roasted compared with unroasted GSC. The small increases in yield of milk protein and lactose observed in the previous production trial in cows fed diets containing roasted corn may have occurred because of greater supply of fermentable substrates.