20 research outputs found
Effect of Dietary Zinc Oxide on Morphological Characteristics, Mucin Composition and Gene Expression in the Colon of Weaned Piglets
The trace element zinc is often used in the diet of weaned piglets, as high
doses have resulted in positive effects on intestinal health. However, the
majority of previous studies evaluated zinc supplementations for a short
period only and focused on the small intestine. The hypothesis of the present
study was that low, medium and high levels of dietary zinc (57, 164 and 2,425
mg Zn/kg from zinc oxide) would affect colonic morphology and innate host
defense mechanisms across 4 weeks post-weaning. Histological examinations were
conducted regarding the colonic morphology and neutral, acidic, sialylated and
sulphated mucins. The mRNA expression levels of mucin (MUC) 1, 2, 13, 20,
toll-like receptor (TLR) 2, 4, interleukin (IL)-1β, 8, 10, interferon-γ
(IFN-γ) and transforming growth factor-β (TGF-β) were also measured. The
colonic crypt area increased in an age-depending manner, and the greatest area
was found with medium concentration of dietary zinc. With the high
concentration of dietary zinc, the number of goblet cells containing mixed
neutral-acidic mucins and total mucins increased. Sialomucin containing goblet
cells increased age-dependently. The expression of MUC2 increased with age and
reached the highest level at 47 days of age. The expression levels of TLR2 and
4 decreased with age. The mRNA expression of TLR4 and the pro-inflammatory
cytokine IL-8 were down-regulated with high dietary zinc treatment, while
piglets fed with medium dietary zinc had the highest expression. It is
concluded that dietary zinc level had a clear impact on colonic morphology,
mucin profiles and immunological traits in piglets after weaning. Those
changes might support local defense mechanisms and affect colonic physiology
and contribute to the reported reduction of post-weaning diarrhea
Changes in ruminal volatile fatty acid production and absorption rate during the dry period and early lactation as affected by rate of increase of concentrate allowance
The aim of the present experiment was to study changes in volatile fatty acid (VFA) production using an isotope dilution technique, and changes in VFA fractional absorption rate (k aVFA) using a buffer incubation technique (BIT) during the dry period and early lactation, as affected by the postpartum (pp) rate of increase of concentrate allowance. The current results are complementary to previously reported changes on rumen papillae morphology from the same experiment. From 50 d antepartum to 80 d pp, VFA production rate was measured 5 times and k aVFA was measured 10 times in 12 rumen-cannulated Holstein Friesian cows. Cows had free access to a mixed ration, consisting of grass and corn silage, soybean meal, and (dry period only) chopped straw. Treatment consisted of either a rapid (RAP; 1.0 kg of DM/d; n = 6) or gradual (GRAD; 0.25 kg of DM/d; n = 6) increase of concentrate allowance (up to 10.9 kg of DM/d), starting at 4 d pp, aimed at creating a contrast in rumen-fermentable organic matter intake. For the BIT, rumen contents were evacuated, the rumen washed, and a standardized buffer fluid introduced [120 mM VFA, 60% acetic (Ac), 25% propionic (Pr), and 15% butyric (Bu) acid; pH 5.9 and Co-EDTA as fluid passage marker]. For the isotope dilution technique, a pulse-dose of 13C-labeled Ac, Pr, and Bu and Co-EDTA as fluid passage marker was infused. The rate of total VFA production was similar between treatments and was 2 times higher during the lactation (114 mol/d) than the dry period (53 mol/d). Although papillae surface area at 16, 30, and 44 d pp was greater in RAP than GRAD, Bu and Ac production at these days did not differ between RAP and GRAD, whereas at 16 d pp RAP produced more Pr than GRAD. These results provide little support for the particular proliferative effects of Bu on papillae surface area. Similar to developments in papillae surface area in the dry period and early lactation, the k aVFA (per hour), measured using the BIT, decreased from 0.45 (Ac), 0.53 (Pr) and 0.56 (Bu) at 50 d antepartum to 0.28 (Ac), 0.34 (Pr) and 0.38 (Bu) at 3 d pp. Thereafter, k aVFA (/h) rapidly increased up to 0.67 (Ac), 0.79 (Pr), and 0.79 (Bu) at 80 d pp. Although papillae surface area was greater at 16, 30, and 44 d pp in RAP than GRAD, no differences in k aVFA between RAP and GRAD were observed during these days showing papillae surface area is not the limiting factor for k aVFA during early pp adaptation