The effect of Saccharomyces cerevisiae and Aspergillus oryzae on fermentations in the rumen of faunated and defaunated sheep; protozoal and probiotic interactions

We measured the effect of the direct addition to the rumen of Saccharomyces cerevisiae (SC 50 mg/day) and Aspergillus oryzae (AO 3 g/day) on the fermentation processes in fistulated sheep. The measurements were carried out on animals whose rumens were first defaunated and then refaunated. The animals received a ration composed of hay (600 g/day), barley (600 g/day) and soybean meal (150 g/day), fed twice daily in two equal meals. The number of fungi and total, viable or cellulolytic bacteria were lower after the inoculation of protozoa in defaunated rumens. The probiotics stimulated the development of total bacteria but reduced the population of cellulolytic bacteria. The addition of the probiotics and the presence of protozoa each incurred a decrease in the redox potential values. The association of both treatments had an additive effect on this parameter. The two probiotics and the protozoa stabilized the rumen pH after the meal, maintaining it above the value of 6 for a longer period of time. The positive effects on pH were accumulated in the refaunated animals receiving probiotics. The ammonia nitrogen concentration was considerably increased by the presence of the protozoa; the probiotics increased the ammonia concentration only in the refaunated sheep. The methane and hydrogen proportions in the fermentation gases were invariably higher in the refaunated animals. The probiotics had no clear effect either on the gas composition or the concentration and the composition of the mixture of volatile fatty acids; only the concentration of isovalerate was significantly increased by probiotics and only in refaunated animals. The protozoa did, however, considerably increase the concentrations of acetate, butyrate and isoacids and decreased the concentration of caproate.

Effect of ruminal inoculation of Isotricha alone or a mixed B-type fauna in a defaunated rumen on the digestion of a hay-maize diet (70:30) in sheep

Two adult sheep (75 kg live weight) fitted with rumen cannulas were defaunated by the emptying method during the first period of the experiment. They were inoculated with the genus Isotricha alone during the second period, and with a mixed ciliate population (Entodinium, Eudiplodinium, Epidinium) during the third. They were fed a diet of grass hay (840 g) and pelleted maize grains (360 g) in 8 meals per day, every 3 h. Defaunation was successful and no accidental contamination occurred during the experiment. The protozoa had no significant effect on the volume of rumen digesta, nor on the turnover of the particulate phase. The addition of Isotricha and of the mixed fauna increased the ADF digestibility of the diet but, in the same animals, lowered the in sacco degradation of wheat straw. The ruminal pool sizes of dry matter (DM), organic matter (OM), nitrogen (N), neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid lignin detergent (ADL) remained unchanged after protozoa inoculations. The concentration of total volatile fatty acids (VFA) was not altered by faunation with Isotricha or a mixed fauna. The molar proportion of acetate increased at the expense of all the other VFAs (mainly propionate with the mixed fauna). Correspondingly, the proportion of methane in the rumen gases increased and that of CO2 decreased in inoculated animals. The ammonia concentration was highest in animals with a mixed fauna and lowest in those inoculated with Isotricha alone. This trend is explained in terms of the specific effect of the different genera of protozoa on nitrogen metabolism.

Digestion of a dehydrated lucerne/barley diet (70:30) in defaunated, Isotricha-monoinoculated and mixed-fauna-inoculated rumen in sheep

Two adult Texel sheep fitted with permanent rumen fistulae were defaunated for 12 weeks in a preliminary experiment. They were then reinoculated with Isotricha sp for 11 weeks, and finally with a mixed fauna (Entodinium, Epidinium, Eudiplodinium and Isotricha) for 10 weeks. They were fed a diet composed of dehydrated lucerne (700 g/d), pelleted barley grain (300 g/d), grass hay (100 g/d) and wheat straw (50 g/d) in one daily meal. Isotricha and the ciliates of the mixed fauna developed rapidly, reaching a maximum concentration 9-17 d after inoculation. Their concentration then fell for 2-3 d and finally stabilized at values close to 10(4)/ml for Isotricha, Eudiplodinium and Epidinium and 2.5 x 10(5)/ml for Entodinium. The estimated ciliate biomass in the rumen was 1.8 g l-1 for a volume of 10.2 ml l-1 in the Isotricha-monoinoculated sheep and 4.7 g l-1 for a volume of 25.0 ml l-1 in mixed-fauna-inoculated sheep. The concentration of Isotricha was unaffected by the inoculation of mixed fauna during the third part of the experiment. No difference in total rumen bacteria counts was observed between defaunated, monoinoculated and completely refaunated animals. The total adenylic nucleotide concentration in filtered rumen juice was 4 times higher in faunated sheep just before feeding and 4-9 times lower after feed intake as compared to defaunated animals; the energy charge was always higher in faunated animals. These results are discussed in relation to the digestive activity and biomass of the protozoa. The in situ degradation of lucerne stems was the highest in the mixed-faunated sheep over a retention time interval of 6-18 h. The values obtained in Isotricha-monoinoculated sheep were intermediate between the defaunated and the mixed-faunated states. The digestibility in the whole digestive tract of dietary dry matter, organic matter, nitrogen and neutral detergent fibre was unaffected by the addition of either Isotricha or the mixed fauna in defaunated rumens. The total volatile fatty acid concentration was higher (p < 0.05) in the defaunated sheep between 6 and 18 h after feeding. The molar proportion of butyrate was significantly (p < 0.05) increased by the presence of mixed fauna in the rumen while that of propionate and valerate was lower. A non-significant decrease in acetate was also observed. The concentration of NH3-N in the rumen was significantly increased (p < 0.05) by the presence of the mixed fauna in the rumen but was unaffected or slightly reduced by Isotricha alone.(ABSTRACT TRUNCATED AT 400 WORDS)

Two types of globidium-cysts of goats

In the abomasum of naturally infected goats two types of globidium were found. An electron microscopic study revealed that the parasites were different from those described from sheep in former publications.

Three new types of globidium of sheep: an in vivo and in vitro investigation

The abomasum and duodenum of sheep contained three types of globidium. The size and fine structure of these globidium differed from those described in previous investigations. The highly motile parasites failed to develop in cell lines of goat, sheep and dog origin.

Besnoitia sp. from goats in Kenya

The eyelids of goats in Kenya contained several, conspicuous white cysts which were up to 1.5 mm in size. By histological and electron microscopical studies it was confirmed that these cysts belong to the genus Besnoitia.

Fine structure of microgametogenesis of Eimeria ferrisi Levine and Ivens 1965 in Mus musculus

The microgamogony of Eimeria ferrisi from experimentally infected mice was investigated with the electron microscope. Microgamonts were recognizable by the presence of peripherally arranged nuclei and the presence of single or paired centrioles between each nucleus and the limiting membrane of the parasite. Often an intranuclear centrocone directed toward the centriole was present. Differentiation of the microgamete began when elevations of the limiting membrane, which indicated the commencement of flagellar development, appeared above the centrioles. This event was accompanied by the segregation of nuclear content into a dense osmiophilic portion and an electron-pale portion. Then followed a gradual protrusion of the dense portion of the nucleus and developing flagella into the parasitophorous vacuole. A dense ring developed at the base of the differentiating microgamete, resulting in the formation of a stalk which was occupied by the residual portion of the nucleus. Fully developed microgametes became detached and occupied the parasitophorous vacuole along with residual cytoplasm. Microgametes had an anterior perforatorium, a dense elongate nucleus, with an anteriorly positioned mitochondrion in a small groove of the nucleus. Usually two flagella were present but one microgamete appeared to have three. Polysaccharide first appeared when differentiation was in progress and increased until large numbers of granules were present in the microgamont cytoplasm.

The ultrastructure of macrogametes of Eimeria ferrisi Levine and Ivens 1965 in Mus musculus

Macrogametes of Eimeria ferrisi occurred in epithelial cells of the cecum and colon of Mus musculus and were studied by electron microscopy. Young stages were identified as macrogamonts by the presence of wall-forming bodies. At first an outerlimiting membrane and remnants of the inner membrane complex of the former merozoite pellicle were present; the latter was later lost but in mature macrogametes 3 limiting membranes were observed. Type II wall-forming bodies appeared before type I; the former developed in expanded cisternae of the endoplasmic reticulum whereas the latter were smaller in size and appeared in the ground substance of the cytoplasm. After formation of the oocyst wall the bodies of the 2 types were no longer visible. The presenceodies of the 2 types were no longer visible. The persistence of micronemes in mature macrogametes and the presence of numerous layers of rough endoplasmic reticulum during wall formation have not been previously reported.

A fine structural study of asexual stages of the murine coccidium Eimeria ferrisi Levine and Ivens 1965

The schizogony of Eimeria ferrisi was studied in experimentally infected Mus musculus. Developmental stages occurred in epithelial cells of the cecum and colon. During transformation of invasive stages into schizonts the inner membrane complex of the pellicle, the conoid, subpellicular microtubules and micronemes gradually disappeared. The micropore, however, seemed to persist. Dividing nuclei had eccentric intranuclear spindles consisting of microtubules which extended between 2 centrocones, in close relationship with centrioles. During the last nuclear division anlagen of merozoites appeared as extensions on the surface of schizonts. The outer single membrane of the schizont became the outer membrane of the merozoite pellicle. Cytoplasmic organelles, typical of eimerian merozoites were incorporated into the developing merozoites. Finally the merozoite became detached leaving behind a residual cytoplasm. Fully developed merozoites had a 3-layered pellicle, the outer single unit membrane was continuous around the merozoite with the inner complex having interruptions at the anterior and posterior poles and at the micropores. Thirty-two subpellicular microtubules, originating at the anterior polar ring extended to the posterior region of each merozoite. The apical complex consisted of a conoid, preceded by 2 rings and surrounded by a polar ring. Two rhoptries were present having club-shaped terminal ends and slender ductules in the conoid region. Some merozoites had enlarged rhoptries, with the distal vesical appearing dense and osmiophilic. The Golgi complex, endoplasmic reticulum, mitochondria, polysaccharide granules were similar to those seen in other eimerian merozoites.

Electron microscope studies of cyst stages of Sarcocystis tenella: the origin of micronemes and rhoptries

The origin and the development of the micronemes and rhoptries was investigated at the ultrastructural level in cyst stages of Sarcocystis tenella. During endodyogeny the micronemes appear in small vesicles distributed at the periphery of two large granular vacuoles in each daughter cell. Later, these vacuoles were divided into numerous vesicular spiral formation-centers, producing micronemes at the apical pole of young merozoites. Rhoptries were observed to originate from desnifications with in the same large vacuoles which gave rise to the micronemes.