This experiment was conducted to investigate the effects of live yeast and yeast cell wall polysaccharides on growth performance, rumen function and plasma lipopolysaccharides (LPS) content and immunity parameters of beef cattle. Forty Qinchuan cattle were randomly assigned to one of four treatments with 10 replicates in each treatment. The dietary treatments were: control diet (CTR), CTR supplemented with 1 g live yeast (2×1010 live cell g–1 per cattle per day (YST1), CTR supplemented with 2 g live yeast per cattle per day (YST2) and CTR supplemented with 20 g of yeast cell wall polysaccharides (30.0%≤β-glucan≤35.0%, and 28.0%≤mannanoligosaccharide≤32.0%) per cattle per day (YCW). The average daily gain was higher (P=0.023) and feed conversion ratio was lower (P=0.042) for the YST2 than the CTR. The digestibility of neutral detergent fiber (P=0.039) and acid detergent fiber (P=0.016) were higher in yeast supplemented groups. The acetic acid:propionic acid of the YST2 was lower compared with the CTR (P=0.033). Plasma LPS (P=0.032), acute phase protein haptoglobin (P=0.033), plasma amyloid A (P=0.015) and histamine (P=0.038) were lower in the YST2 compared with the CTR. The copies of fibrolytic microbial populations such as Fibrobacter succinogenes S85, Ruminococcus albus 7 and Ruminococcus flavefaciens FD-1 of the YST2 were higher (P<0.001), while the copies of typical lactate producing bacteria Streptococcus bovis JB1 was lower (P<0.001) compared with the CTR. Little differences were observed between the CTR, YST1 and YCW in growth performance, ruminal fermentation characteristics, microbial populations, immunity indices and total tract nutrient digestibility. It is concluded that the YST2 could promote fibrolytic microbial populations, decrease starch-utilizing bacteria, reduce LPS production in the rumen and LPS absorption into plasma and decrease inflammatory parameters, which can lead to an improvement in growth performance in beef cattle.
Although fungal communities in the gastrointestinal tract have a significant role in animal health and performance, their dynamics within the tract are not well known. Thus, this study investigated fungal community dynamics in the rumen and rectum of lambs from birth to 4 mon of age by using IT1S rDNA sequencing technology together with the RandomForest approach to determine age-related changes in the fungal ecology. The results indicated that gastrointestinal fungal community composition, diversity, and abundance altered (P<0.05) with the increasing age of the lambs. Two phyla, Ascomycota and Basidiomycota, dominated the samples. Similarity within age groups of the rumen fungi increased sharply after 45 days of age, while the similarity increased (P<0.05) significantly after 60 days of age in the rectum. The age-related genera, Acremonium, Microascus, Valsonectria, Myrmecridium, Scopulariopsis, Myrothecium, Saccharomyces, and Stephanonectria, were presented in both ruminal and rectal communities, and their changes in relative abundance were consistent at both sites. The principal coordinates analysis showed significant differences (P<0.05) between the fungal communities in the rumen and rectum. Our findings demonstrate that both the age of lambs and the gastrointestinal tract region can affect the composition of these fungal communities, and this provides new insight and directions for future studies in this research area.
Grain-induced subacute ruminal acidosis (SARA) impairs rumen epithelial barrier function, but it is yet to be determined if SARA can cause persistent damage to the morphology and function of the rumen epithelial barrier. The objective of the present study was to investigate if SARA has persistent effects on the morphological structure and permeability of ruminal epithelium and the expression of the genes involved in epithelial barrier function using a lactating goat model. Twelve mid-lactating Saanen goats with rumen cannulas were randomly assigned to 1 of 2 groups: control group (Ctrl, n=4) fed a basal diet with a non-fiber carbohydrate (NFC) to neutral detergent fiber (NDF) ratio of 1.40, and SARA group (SARA, n=8) fed the same basal diet but with increasing NFC to NDF ratio from 1.4 to 1.79, 2.31, and 3.23 overtime to induce SARA. At the end of the SARA challenge (post-SARA), 4 goats were randomly selected from the SARA group and fed only hay mixture ad libitum for another 4 weeks to allow for restitution (post-SARA). Ruminal pH was continuously recorded to monitor the severity of SARA. Samples of the ventral ruminal epithelium were collected after slaughter to examine the structural and functional changes of the ruminal epithelium using transmission electron microscopy (TEM), Ussing chambers, qRT-PCR, and Western bolt analyses. Compared with the Ctrl group, ruminal papilla length, width, surface area and thickness of stratum corneum increased (P<0.05), while stratum spinosum and basale thickness, and total depth of the epithelium decreased (P<0.05) in the SARA group. These changes diminished or tended to return to the levels of the Ctrl group in the post-SARA group (P>0.05). The SARA challenge also decreased cellular junction and widened the intercellular space between epithelial cells. Rumen transepithelial short-circuit current (Isc), tissue conductance (Gt), and mucosa-to-serosa flux of paracellular horseradish peroxidase (HRP) all increased (P<0.05) both in the SARA and post-SARA groups, which indicates that SARA can induce a sustained increase in epithelial permeability and barrier dysfunction. Moreover, the mRNA and protein expressions of CLDN1, OCLN and ZO-1 were down-regulated (P<0.01) in both the SARA and post-SARA groups. The results of this study showed that SARA could result in sustained epithelial barrier dysfunction, at both structural and functional levels, which is associated with decreased expression of rumen epithelial tight junction proteins, and the restitution of rumen epithelial barrier function is slower than that of its morphology.
Copyright © Journal of Integrative Agriculture
Sponsored by Chinese Academy of Agricultural Sciences (CAAS)
Co-sponsored by China Association of Agricultural Science Societies (CAASS)
Publishing Service by Elsevier B.V.
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