Rumen Ciliate Protozoa of the Blue Duiker (Cephalophus monticola), with Observations on Morphological Variation Lines Within the Species Entodinium dubardi

ABSTRACT. Protozoal concentrations were determined in rumen and cecal contents of 20 blue duikers ( Cephalophus monticola ). Ten animals of each sex were fed either a high concentrate or high roughage diet. Rumen protozoa were present in 19 of the 20 animals and concentrations ranged from 4.5 to 33.7 × 10⁶ per g of rumen contents. At the higher concentrations, protozoal cells equaled between 30–40% of the total rumen contents volume. No protozoa were found in cecal contents. Weight of rumen contents was higher in females than in males ( P < 0.01), and rumen protozoa concentrations were higher in males ( P < 0.05) and in those animals fed the high concentrate diet ( P < 0.05). All the protozoa were identified as belonging to a single species, Entodinium dubardi . However, an average of about 30% of the E. dubardi cells varied from the typical morphology of this species. These cells appeared to be on variation lines leading toward 7–10 other non-caudate species of Entodinium . The present data were used to evaluate and discuss the concept of variation lines within E. dubardi .     

Metabolic and stress responses in dairy cows fed a concentrate-rich diet and submitted to intramammary lipopolysaccharide challenge

Feeding dairy cows diets rich in grain often leads to subacute rumen acidosis (SARA), which might affect their responsiveness to immunogenic stimuli such as exogenous lipopolysaccharide (LPS), and can lead to metabolic alterations. The main objective of this study was to investigate if SARA affects the stress and metabolic health responses resulting from an intramammary LPS challenge. Before the intramammary LPS challenge, the SARA cows showed higher blood glucose and a tendency for higher lactate and aspartate aminotransferase as well as a trend toward lower β-hydroxybutyrate (BHBA) and γ-glutamyltransferase compared with control cows. After the LPS challenge, the serum cortisol concentration markedly increased and the calcium concentration decreased both in SARA and control cows. In SARA-LPS cows, however, the lactate concentration increased due to the LPS infusion, whereas it remained unchanged in the control cows. A lower serum BHBA concentration was found in SARA-LPS compared with control-LPS cows. Higher non-esterified fatty acid concentrations were found in control-LPS cows shortly before the LPS challenge compared with SARA cows, challenged or not with LPS, whereas it did not differ from SARA-LPS cows thereafter. In conclusion, the results suggest that intramammary LPS challenge induced stress and lowered calcium concentration in all dairy cows, whereby this challenge showed lower BHBA and higher lactate levels in cows with SARA conditions.     

Energy supply of the okapi in captivity: intake and digestion trials

In the nutrition of browsing ruminants in captivity, adequate nutrient digestibility and energy content of diet is debated. Problems related to energy‐provision and low forage intake have been reported for the okapi and other browsers like the giraffe, particularly during winter. High‐fiber concentrates like unmolassed beet pulp have some potential to improve the nutritional management of these species. Using a total of six okapis in captivity, seven feeding trials were carried out at two facilities (A+B) on a structured but opportunistic base. Three trials (A₁, A₂, B₁) were conducted when animals were fed their regular diet including grain based energy concentrates, fruits and vegetables, and alfalfa (Medicago sativa) hay. Two trials (A₅, B₂) examined the effect of unmolassed beet pulp, and two (A₃,₄) examined the effect of unmolassed beet pulp+fresh browse. Daily intake and feces production were quantified over 8–12 days. Samples were analyzed for dry matter, crude ash, neutral detergent fiber (NDF)/acid detergent fiber (ADF)/acid detergent lignin (ADL), crude protein, and gross energy. Metabolizable energy content of diets was estimated via a factor (0.83) from digestible energy. The proportion of beet pulp in diets was 13% (A₃), 24% (A₄), 20% (A₅), and 21% (B₂). Browse proportion was 11% (A₃) and 32% (A₄). Daily feed intake ranged between 1.5–1.7% of body weight (BW), digestibility of organic matter between 61–74%. Digestibility of fiber (NDF) was higher in beet pulp diets (A₃=39%, A₄=60%, A₅=54%, B₂=61%) than in the others (A₁=48%, A₂=33%, B₁=48%). Supply of metabolizable energy (ME) ranged between 0.50–0.70 MJ ME/(kg BW^0.75*day), meeting energy requirements of okapis of 0.50–0.53 MJ ME/(kg BW^0.75*day) in general. Diets with beet pulp+browse were not found to be highest, but in the upper level of the range of forage proportions of this study. Palatable browse species were preferred over all other feedstuff offered. The use of unmolassed beet pulp as energy‐concentrate for browsing ruminants like the okapi can be recommended because diets high in this high‐fibre feedstuff resulted in adequate energy intakes. Zoo Biol 0:1–14, 2006. © 2006 Wiley‐Liss, Inc.     

Community dynamics of Neocallimastigomycetes in the rumen of yak feeding on wheat straw revealed by different primer sets

Anaerobic fungi (Neocallimastigomycetes) play an important role in fermenting lignin-rich plant biomass into sugars in the rumen of animals, representing a very promising enzyme resource to contribute to the conversion of plant biomass into biofuels. However, current studies about their functions mainly focus on limited species, and little is known about the coordination of different members of the anaerobic fungi in the digestion process of plant fibres. In this study, the community composition of anaerobic fungi in the rumens of yaks at five different time points (1, 3, 5, 7.5 and 24 h after feeding wheat straw) was investigated employing a cultivation-independent method using ITS clone libraries. Comparison of five pairs of primers showed that PCR primer sets could have clear amplification bias and therefore potentially affect the interpretation of the resulting fungal community structure; then two primer sets GM1/MNGM2 and ITS1/ITS4 were selected. Among the 398 sequences from 10 clone libraries, 18 operational taxonomic units (OTUs) of Neocallimastigomycetes were obtained, covering five known genera and one yet uncultured lineage. OTUs belonging to the bulbous-type morphotype (Caecomyces- or Cyllamyces-related) and the rhizoidal genus Neocallimastix were abundant and predominantly present, representing 62.7% and 19.3% OTUs respectively. In all the later samples taken from 3 h to 24 Neocallimastigomycetes h after feeding, a relatively stable community composition was revealed: members of Neocallimastix increased to represent 43.4–49.4% and the bulbous-type morphotype declined to represent 39.5–42.7%. This implies a substantial turnover and synergy between bulbous and rhizoidal morphotypes of anaerobic fungi during the process of fibre digestion. Our study provided the first insight into the in vivo temporal change in the anaerobic fungal community, and the role of Neocallimastigomycetes with a bulbous morphotype in the degradation of plant cell wall in the yak rumen.     

Response of rumen microbiota,and metabolic profiles of rumen fluid,liver and serum of goats to high-grain diets

Feeding ruminants a high-grain (HG) diet is a widely used strategy to improve milk yield and cost efficiency. However, it may cause certain metabolic disorders. At present, information about the effects of HG diets on the systemic metabolic profile of goats and the correlation of such diets with rumen bacteria is limited. In the present study, goats were randomly divided into two groups: one was fed the hay diet (hay; n = 5), while the other was fed HG diets (HG; n = 5). On day 50, samples of rumen contents, peripheral blood serum and liver tissues were collected to determine the metabolic profiles in the rumen fluid, liver and serum and the microbial composition in rumen. The results revealed that HG diets reduced (P < 0.05) the community richness and diversity of rumen microbiota, with an increase in the Chao 1 and Shannon index and a decrease in the Simpson index. HG diets also altered the composition of rumen microbiota, with 30 genera affected (P < 0.05). Data on the metabolome showed that the metabolites in the rumen fluid, liver and serum were affected (variable importance projection > 1, P <0.05) by dietary treatment, with 47, 10 and 27 metabolites identified as differentially metabolites. Pathway analysis showed that the common metabolites in the shared key pathway (aminoacyl-transfer RNA biosynthesis) in the rumen fluid, liver and serum were glycine, lysine and valine. These findings suggested that HG diets changed the composition of the rumen microbiota and metabolites in the rumen fluid, liver and serum, mainly involved in amino acid metabolism. Our findings provide new insights into the understanding of diet-related systemic metabolism and the effects of HG diets on the overall health of goats.     

Genetic diversity in Selenmonas ruminantium isolated from the rumen

Abstract Non-denaturing polyacrylamide gel electrophoresis was used to detect genetic variation at loci coding for there intracellular enzymes in the obligately anaerobic rumen bacterium Selenomonas ruminantium . Four mobility variants were detected for lactate dehydrigenase, seven for glucokinase and at least five for NADP-dependent glutamate dehydrogenase among 28 newly isolated, and eitght previously isolated strains from sheep and cattle. No evidence was found for an exclusive association of any particular electrophoretic mobility type with variable metabolic traits such as the ability to utilise lactate, to reduce nitrate or to ferment trehalose, sorbitol, rhamnose or glycerol. The most commonly occurring electromorph type was recovered from more than one animal, while most animals examined were show to harbour more than one electromorph type.