Effect of early establishment of ciliate protozoa in the rumen on microbial activity and growth of early weaned buffalo calves

Influence of rumen ciliate protozoa on conversion of food and growth rate in early-weaned zebu calves

The ruminal activity, daily live-weight gain and feed conversion efficiency of zebu calves inoculated with whole rumen contents from a mature cow were compared with those of calves maintained under the same conditions except that they were ciliate-free and isolated from other ruminants.

A thriving mixed population of ciliate protozoa became established in the rumen of calves two weeks after inoculation.Entodiniumwas the first genus to appear and was followed byIsotricha, Polyplastron, Ophryoscolex, DiplodiniumandDasytricha.

The ruminal volatile fatty acid and ammonia concentrations in the inoculated calves showed a pronounced rise above the values found in the uninoculated controls.

The inoculated calves grew faster and had a higher feed conversion efficiency than the uninoculated controls.

Postweaning age effects on rumen fermentation end-products and digesta kinetics in calves weaned at 5 weeks of age

Four rumen-cannulated calves were used in a block design to study changes in rumen fermentation end-products and rumen digesta kinetics after weaning. Calves were weaned at 5 wk of age and had access to dry feed from d 3 of age. Dietary DM consisted of 85% concentrate and 15% forage. The experiment was divided into three periods: 2, 4, and 8 wk after weaning. Rumen fluid samples collected each period were analyzed for pH, VFA, NH3 N, bacterial DM concentrations, and protozoa numbers. Calves were dosed ruminally with Co-EDTA and Yb-mordanted grain and then sampled for estimation of rumen fluid and particle turnover rates during each period. Average daily gain, DMI, and BW gain increased over the three periods by 106, 81, and 42%, respectively. Rumen pH increased .32 units, and rumen volume increased twofold, during the three periods. Rumen NH3 N concentration and diurnal NH3 N variation changed significantly with age. Bacterial DM concentrations, VFA, and digesta kinetics in the rumen did not change with age. We conclude that the metabolic and physical changes that take place in the rumen of young calves after weaning are evidence of gradual development and yield important information for further study on degradation and metabolism of dietary components in the rumen.

The role of rumen protozoa in the utilization of paspalum (Paspalum dilatatum) hay by cattle

Six Friesian heifers (250 kg live weight) with permanent cannulas in the rumen and abomasum were allocated at random into two groups of three. One group was treated with Teric GN9 (ICI (Aust.) Ltd) to defaunate the animals during the first two of the four periods of the experiment, after which they were refaunated. The second group was treated with Teric at the end of the first two periods. The dietary treatments were: paspalum (Paspalum dilatatum) hay (4.1 kg/d) given alone and the hay supplemented with urea (20 g/kg dry matter). Defaunation was not complete but the approximate volume of protozoa in the rumen of treated animals was less than 6% of that in the untreated animals. The amount of organic matter (OM) digested in the stomach was lower (P less than 0.01) in animals with reduced fauna than in those with normal fauna. There were reductions in both the apparent OM digestibility in the total tract (from 0.56 to 0.52, P less than 0.01) and the proportion of the digestible OM digested in the rumen (from 0.82 to 0.79, not significant) of animals with reduced fauna. Apparent digestibilities of acid-detergent fibre and neutral-detergent fibre were significantly lower (P less than 0.01) in animals with reduced fauna. The amount of nitrogen disappearing from the stomach was significantly higher (P less than 0.01) with the urea supplement; effects due to concentrations of protozoa were not significant. The flow of non-ammonia-N from the abomasum was higher (P less than 0.05) in animals with reduced fauna than in animals with normal fauna. The flows of bacterial N from the abomasum and the efficiencies of bacterial N synthesis were not significantly affected by the treatments. N retention was higher (P less than 0.01) in animals receiving the urea supplement but differences due to protozoa were not significant. Protozoal contribution to the microbial N flowing from the rumen of animals with normal fauna was estimated to be 24 and 27% with and without the urea supplement respectively. Concentrations of rumen-fluid ammonia-N were reduced (P less than 0.05) and those of volatile fatty acids were increased (P less than 0.01) with reduction in protozoal numbers. Molar proportions of propionic acid increased (P less than 0.05) and of butyric acid decreased (P less than 0.01) with reduced rumen fauna.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of defaunation and refaunation of the rumen on rumen fermentation and N-flow in the duodenum of sheep

In order to confirm earlier fragmentary results, the effect of defaunation and refaunation of the rumen on the fermentation pattern and flow of N-components in the proximal duodenum of two sheep was investigated. Defaunation had no effect on acetic acid as a proportion of the total volatile fatty acids in the rumen, while the proportions of propionic acid increased with a concomitant decrease in butyrate. Refaunation resulted in lower acetic acid and higher butyric acid proportions. The concentration of ammonia N in the rumen was clearly decreased after defaunation, already indicating an effect of the elimination of protozoa on nitrogen metabolism in the rumen. Defaunation also increased significantly the flow of total N, non ammonia N and individual and total amino acids in the proximal duodenum. Defaunation resulted in higher bacterial growth efficiency, significantly in one sheep, but the decrease after refaunation was statistically significant for both sheep. Determination of rumen digestibility of organic matter and acid detergent fibre (ADF) revealed lower values in the absence of the protozoa, while total digestibility was only influenced to a much lower extent. This indicated a shift of digestion from rumen to the lower digestive tract. Finally, earlier work is discussed in the light of the present findings.

Negative correlation between protozoal and bacterial levels in rumen samples and its relation to the determination of dietary effects on the rumen microbial population

The bacterial protein content and protozoal protein content of unfractionated samples from the liquid-small particle phase of the rumen were determined on the basis of direct microscopic measurement of bacteria numbers and protozoa numbers and cell volumes. Standard values of 8.7 X 10(-11) mg of protein per bacterial cell and 5.9 X 10(-11) mg/micron 3 of protozoa cell volume, obtained from analysis of isolated cells, were used to convert the microscopic measurements to an estimate of the protein content of the rumen sample. When the correlation between bacterial and protozoal protein levels was examined within groups of animals, a highly significant negative correlation between these two parameters was found (P less than 0.001). The variation among animals for total (bacterial plus protozoal) microbial protein was smaller than the variation among animals for bacterial or protozoal protein alone. There was also a highly significant positive correlation (P less than 0.001) between protozoal protein level and total microbial protein level. The variation found among animals in total microbial protein level could be reduced by using a regression equation determined for bacterial versus protozoal protein to correct for the different population dynamics of the two groups.

Rumen ciliate protozoa: effects on digestion in the stomach of sheep

Six wethers, each fitted with a rumen cannula and duodenal reentrant cannula, were used to study effects of ciliate protozoa on rumen digestion and metabolism. A corn: corn silage (1:1) diet was fed for two periods. During the first period, defaunation was attempted with nonyl phenol ethylene oxide. Defaunation was complete in three sheep and partial in the other three sheep in which a reduced population of a small Entodinium sp. was observed. During the second period the sheep were inoculated with ciliate protozoa, which established a large population in all animals. Apparent digestion in the stomach of organic matter and starch was higher when a large protozoal population was present. Amino acid flow through the duodenum was greater in defaunated animals. A large population of ciliates was associated with increases in both rumen ammonia and plasma urea but had a stabilizing effect on ruminal pH. Volatile fatty acids were higher in the defaunation period, but there were only small differences of molar proportions of the acids between the two periods. Effects of ciliate protozoa are related to animal performance.

Ciliate protozoa in the rumen of Brazilian water buffalo, Bubalus bubalis Linnaeus

Total numbers and distribution of genera, subgenera and species were determined for the ciliate protozoa in rumen contents of 4 Brazilian water buffalo Bubalus bubalis Linnaeus. The fauna of one animal, housed in close proximity to European and zebu-type cattle, differed considerably from that of the remaining animals, which were somewhat isolated on a large ranch. Several of the protozoan species observed in the semi-isolated animals were first described in rumen contents from humped Indian cattle, and their subsequent occurrence in other hosts and geographic locations has been limited or absent. In all, 49 different species of protozoa were found, 8 of which have not been previously described. Three of the new species belong to the genus Entodinium: E. ciculum sp. n., E. spinonucleatum sp. n. and E. triangulum sp. n.; 4 to Diplodinium (Ostracodinium): D. (O.) brazili sp. n., D. (O.) esalqum sp. n., D. (O.) nucleolobum sp. n., and D. (O.) tiete sp. n.; and one to Diplodinium (Eudiplodinium): D. (E.) bubalus sp. n.