Keiji Ogimoto

Ciliate Protozoa from the Rumen of the Japanese Serow, Capricornis crispus (Temminck)

The composition of rumen ciliate protozoa from the Japanese serow was investigated. The average number of total ciliates per milliliter of rumen contents was 1.4×105. Eleven species, one of trichostomatid and ten of entodiniomorphid ciliates, were recognized. Of them, ten species had already been described in the domestic ruminants in Japan, but one was detected specifically from the Japanese serow. This species was described as the new form, Epidinium ecaudatum forma capricornisi forma nov. This form had bifurcated and trifurcated caudal spines. Species or formae with trifurcated spines had been described not in the genus Epidinium but in the genus Ophryoscolex. The fact may be one of the characters showing the phylogenetical relationship between these two geneta.

Susceptibility to Eimeria tenella of chickens and chicken embryos of partly inbred lines possessing homozygous major histocompatibility complex haplotypes.

Susceptibility to Eimeria tenella infection of chicken embryos and chickens of partly inbred lines possessing different major histocompatibility complex haplotypes was investigated. Chicken embryos of line H-B2 possessing B2 homozygous haplotype showed lower mortality and higher oocyst production than embryos of line H-B15 possessing B15 homozygous haplotype. Embryos of line H-B2 chickens were considered more resistant to E. tenella infection than those of line H-B15. Seven days after 10-day-old chickens were infected with E. tenella, the two lines showed no significant differences in percent bodyweight gain, cecal lesion score, and oocyst production; they differed significantly only in cecal shrinkage. Results suggest that the B system affects chicken embryos and chickens differently in susceptibility to E. tenella infection.

Experimental infection of chickens with Cryptosporidium.

To study the clinical and pathological manifestations of Cryptosporidium infections, 24 h-old chickens were inoculated via four routes: orally, nasally, cloacally and by contamination, using 10(5) oocysts of Cryptosporidium in each case. The chickens began to shed oocysts of Cryptosporidium on days 7 to 8 after inoculation. There was no difference in the clinical manifestations or histological damage with respect to the inoculation routes. Various developmental stages of Cryptosporidium were also demonstrated microscopically in the smears or sections of bursa of Fabricii, larynx, trachea and cecal tonsils of inoculated chickens. Although the intestinal mucosa and respiratory tract mucosa were scarcely infected with the parasites, the bursa Fabricii was heavily infected in association with hypertrophy and hyperplasia of the lining epithelial cells.

Attenuation of Eimeria tenella by serial passage in chicken embryos.

A strain of Eimeria tenella of Japan origin was serially passaged 51 times in chicken embryos. Any obvious changes of reproductivity and lethality to chicken embryos of the passage strain were not observed. Chickens infected with oocysts passaged 41 times in chicken embryos showed less severe cecal lesions and hemorrhage, and higher values of body weight gain, feed intake and lower value of feed requirment, compared with chickens infected with oocysts passaged once in chicken embryos. Less severe lesions were also observed in chickens infected with oocysts passaged 51 times in chicken embryos than those in chickens with oocysts passaged once. It was indicated that pathogenicity of the strain was attenuated after serial passage in chicken embryos.

A Serological Study of Veillonella alcalescens Isolated from Ruminants

Serological grouping of Veillonella alcalescens strains isolated from the alimentary tract was performed by cross agglutination. There were complicated antigenic relationships among these strains, which were divided basically into two groups. One group consisted of strains of rumen origin and the other of strains of lower alimentary tract origin.When Veillonella alcalescens was examined for antigenic structure, it possessed heat-labile antigen in addition to somatic antigen. Furthermore, it was clarified that formolized antigen was closely related to heat-labile antigen. This heat-labile antigen corresponded to K-antigen of enterobacteria. It resembled C-type antigen found in Proteus, but did not resemble B-type antigen of Neisseria gonorrhoeae.

Propionic Acid Bacteria Producing in the Rumen

Veillonella alcalescensのコハク酸脱炭酸能がルーメン内で増大する可能性について,めん羊ルーメン由来7SR-21株を用い検討した.1. 該菌をコハク酸,酒石酸,乳酸を添加した培地で培養し,各培地の炭素源によつてコハク酸脱炭酸能が変化するか否かを検討した.その結果,本活性は培養時の基質には,大きな影響を受けないことを知つた.2. 回分培養で得られた該菌のコハク酸脱炭酸能の経時変動は対数生育期の末期に最低となり,その後,漸増して48時間後,即ち平衡期にはQco2600以上となつた.この値は該菌の平均活性値のほぼ2倍である.3. 該菌の本活性に及ぼすルーメン液の影響を検討するために,休止菌液を,(a) 高速遠沈で得た除菌ルーメン液と試験管内で嫌気的に37°Cで感作し,(b) 透析袋に入れ瘻管を通じてルーメン内に挿入し,透析性ルーメン液と感作した.その結果,本活性はルーメン液によつて保持され,増大するが,その程度は約2倍であつた.4. 該菌とルーメン菌区分を混合した際の本活性を測定し,他の菌群の影響をみたが,特に増大しなかつた.これらの実験の範囲内では培養されたV.alcalescensの本活性は比較的変動性が少なく,増強されることがあつても数倍にとどまり,ルーメン内V.alcalescensのコハク酸脱炭酸能が単離培養した該菌の活性に等しいと仮定して得られた計算値と,ルーメン細菌区分コハク酸脱炭酸能の実測値の間の大差を説明することが出来ず,従つて,ルーメン内コハク酸脱炭酸能に対する寄与は僅少であろうとの推論は否定されなかつた.

Ecological Studies on Rumen Bacteria and Their Activities

Rumen filtrates collected from sheep fed corn silage and concentrate were examined for diurnal changes in pH, gas production activity, the numbers of aerobic and anaerobic bacteria, and contents of several free B-vitamins (thiamine, riboflavin, pyridoxine, biotin, pantothenic acid and nicotinic acid).Values of pH, gas production activity, free B-vitamins contents and the number of bacteria of the rumen filtrates varied temporarily with the lapse of time after feed had been taken by the animals. Then they returned gradually to their initial levels. The results obtained in this case showed a tendency quite similar to, but more distinct than, that described in the previous paper dealing with goates which had been either grazed or fed hay and concentrate. Furthermore, two distinctive patterns were well noticed in changes in free B-vitamins contents of the rumen filtrates, and their gas production activity was at a signicantly higher level in this case.

Studies on the Rumen Fermentation

1. 各種の飼養条件における山羊および緬羊の第一胃内容液について,発酵管を使用して,ガスおよび揮発性脂肪酸類(VFAs)生成能の日中変化を経時的に追跡し,また第一胃内容液のVFAs濃度の経時的変化をも検索した.2. 飼養条件のいかんを問わず,ガス生成能は,その変動の型として,採食後数時間で起こる第1のピークと16～18時間後に起こる第2の高位のレベルへの高まりとを示した.VFAs生成能の消長でも,同様の型がみられた.3. 性ガス生成能は,生牧草,サイレージ給与時に高いレベルを,また生野草,牧乾草給与時に低いレペルを示した.稲藁給与時には,ガス生成能とVFAs生成能は，いずれもとくに低かつた.4. 胃内のVFAs量は,いずれの飼養条件のもとでも,採食後10～12時間目に最高に達し,以後漸減して，24時間後にはほぼもとのレベルに復帰した．5. 発酵管を使用して測定すると,生成されたガス量と,その開に生成されたVFAs量との間に,正の相開が認められた.

Studies on rumen fermentation

The rumen fermentation and viable counts of microorganisms of the rumen were compared between goats grazed on native fresh grass and those fed hay prepared from native grass. The results and findings obtained are as follows.The viable counts of anaerobes appearing on glucose media were 2.0-9.3×1010 and 8.2×107-7.5×108 per ml of rumen contents of the grazed animal on September 23 and November 3, respectively. Then they were reduced to 2.5-7.5×107 on January 23 during hay feeding. The viable counts of aerobes on glucose media at the same dates were 1.6-7.7×109 (Sept. 23), 10-6.O×107 (Nov. 3), and 2.5×106-3.5×107 (Jan. 23). The conuts of microorganisms, regardless of anaerobes and aerobes, on glucose media showed some decrease at the final stage of grazing and the stage of hay feeding.Changes in viable counts of certain microorganisms occurred after the feed intake. The number of anaerobes on glucose medium decreased 3 hours after feeding, but that of certain anaeroles grown on cellobiose-, succinate-, and lactate-media increased conversely. On the other hand, the number of aerobes on glucose medium increased after feed intake, while organisms on cellobiose-, succinate-, and lactate-media decreased in number.The level of volatile fatty acids in the rumen fluid of a goat was higher during grazing than during hay feeding. Moreover, in the rumen fluid, large amounts of propionic and butyric acids were produced during grazing, but acetic acid was predominant during hay feeding.The pH values of the rumen fluids were 6.4-7.1, showing no difference between grazing and hay feeding.The Eh values of the rumen contents seemed to be lower during grazing than during hay feeding.