S TUDIES by Appleby et al. (1956), Gutierrez and tlungate (1957), Eadie et al. (1959) and Eadie and Hollson (1962) indicated that ciliate protozoa normally inhabiting the rumen exerted considerable influence upon end products of rumen fermentation and upon tureen bacterial populations. The full significance of protozoa to the nutrition of cattle and sheep is not clear. However, Christiansen et at. (1965) and Abou Akkada and El-Shazly (1964) observed increased growth of lambs with protozoa as compared with lambs without ciliate protozoa. These workers observed higher concentrations of volatile fatty acids and ammonia in rumen fluid from faunated lambs, which suggested a faster rate of fermentation in the faunated rumen. The purpose of the present investigation was to study cellulose digestion and volatile fatty acid production in vitro by washed suspensions of rumen protozoa and bacteria. Materials and MethodsFour liters of tureen fluid were collected from a rumen-fistulated steer 6 hr. after feeding 4.5 kg. of a ration consisting of 50% ground ear corn and 50% good quality alfalfa hay. The steer was fed twice daily. The first 2 liters of fluid were collected as described by Christiansen et al. (1962) for isolation of protozoa. The second 2 liters of rumen fluid were coIlected from the upper layer of rumen ingesta for isolation of bacteria.The preparation of the protozoa inoculum consisted of incubation of rumen fluid with 0.05% sucrose and 0.1% maltose at 39 ~ C. for 30 min. Feed particles were removed from the surface of the liquid with a small scoop. The upper liquid layer (about twothirds of the total volume) containing Entidinum and Dasytricha was transferred to another flask and incubated at 39 ~ C. The lower layer containing Diplodinium, Isotricha,

To evaluate nutritional effects induced in calves by feeding soybean trypsin inhibitor, 16 calves were fed 1) raw soybeans, 2) heated soybeans, 3) heated soybeans plus soybean trypsin inhibitor, 4) heated (raw soybeans plus soybean trypsin inhibitor). Ration 1 caused depression of growth and reduced digestibility of protein and fat as compared to Ration 2. No differences were significant in calves fed Rations 3 and 4. The weights and enzymatic activities of pancreas were similar in all groups. Soybean trypsin inhibitor plays a minor role, if any, in calf nutrition.

No abstract

69 LITERATURE CITED 73 ACKNOWLEDGMENTS 82 APPENDIX --83 Procedures 83 Analysis of Variance Tables 93 (1964) and Abou Akkada and El-Shazly (1964). The presence of ciliate protozoa increased total volatile fatty acid production, especially during the first four to six hours after feeding. These same workers also observed a significant increase in concentration of ruminai ammonia during this period. These findings suggest a faster rate of fermentation in the faunated reticulo-rumen. Abou Akkada and El-Shazly (1965) measured the effect of ciliate protozoa upon several blood components and nitrogen retention in lambs. Blood samples taken three hours after feeding were analyzed for blood reducing sugars, hemoglobin, protein nitrogen, non-protein nitrogen, ammonia nitrogen and urea nitrogen. They found faunated lambs had higher levels of blood hemoglobin and blood protein nitrogen, but lower levels of reducing sugars, ammonia nitrogen and urea nitrogen than those of defaunated lambs. Faunated lambs retained 51.2 percent nitrogen compared with 400 percent nitrogen retention for defaunated lambs.Becker ^ (1929b) concluded from their studies that ciliate protozoa neither helped nor harmed the host animal and assigned the ciliate protozoal fraction a status of mere commensals. Research work reported since then has only par tially supported Becker's conclusions; therefore, the exact influence that ciliate protozoa exert on either the host animal or the ruminai bacteria is not clearly defined at the present. 6 The Relationship between Bacteria and Protozoa in the Reticulo-Rumen Appleby et (1956) attempted to demonstrate the presence of bacteria within ciliate protozoa and observed that Isotricha prostoma, Isotricha intestinalis and Dasytricha ruminatium which were fully motile prior to being fixed and stained did not harbor bacteria, however, Entodinium contained large numbers of Streptococcus bovis. It was concluded that intact viable bacteria did not appear to be vital for the life processes of rumen holotrich protozoa. By starving Dasytricha ruminatium from 48 to 72 hours, which decreased the quantity of stored amylopectin, Gutierrez and Hungate(1957) observed by use of phase contrast microscopy that Dasytricha ingested cocci from 0.5 to 0.8 microns in diameter. The ingested bacteria were then isolated, cultured and later fed to a bac terial free preparation of Dasytricha ruminatium. In an in vitro system the protozoa with bacteria divided frequently and remained alive for two weeks as compared to controls free of bacteria which died within 96 hours. It appeared that the holotrich rumen ciliates derive at least part of their nitro genous requirements from the ingestion of bacteria. Two years later Gutierrez and Davis (1959) reported that Entodinium and Diplodinium which had been starved from 48-72 hours ingested ruminai bacteria in large numbers. The amylolytic cocci en gulfed by Entodinium were identified as Streptococcus bovis. LITERATURE CITED Abou Akkada, A. R., J. M. Eadie and B. H. Howard. 1963. The biochemistry of r...