Nutrient and other environmental influences upon rumen protozoal growth and metabolism

Abstract

Results and discussion 169 / y Influence of Diethylstilbestrol Upon Rumen Protozoal Numbers and the Effect of Protozoa Upon Growth Performance of Lambs l80 Methods and procedures l8l Results and discussion 186 CONCLUSIONS AND SUMMARY 192 GENERAL DISCUSSION 195 LITERATURE CITED 200 ACKNOWLEDGEMENTS 211 APPENDIX 212 8 strated with glucose as an end product of cellulose breakdown. Hungate (1943) showed that rumen protozoal breakdown of cellu lose led to a rapid synthesis of food reserves, such as amylopectin or other starch granules. Further studies by Hungate revealed a rapid storage and utilization of starch by rumen protozoa. On the other hand, Heald et al. (1952) indicated that maltose and lactose were not utilized, by rumen protozoa. Oxford (1955) postulated that many of the carbohydrates, such as sucrose, glucose, cellobiose, insulin and levans, were used by protozoa to synthesize amylopectln. Sugden (1953) observed that excess soluble carbohydrates, such as glucose and sucrose, caused protozoal cells to burst. Since four-fifths of the cell weight may be amylopectln, additional soluble carbohydrates may cause additional reactions leading to excess carbon dioxide gas which probably is the cause of cell bursting, especially in Diplodinium (Sugden, 1953). Studies by Heald and Oxford (1953) indicated that Isotrlchs and Dasytricha produce high levels of rumen glucose, fructose, sucrose, raffinose, inulin, rye grass levan and cellobiose. The formed acids were primarily acetic, butyric and lactic, with traces of propionic. Utilization of many of the soluble sugars by rumen proto zoa has been demonstrated by several investigators (Sugden, 1953; Oxford, 195 lj Hungate, 1942 and 1943; Gutierrez, 1953; Heald _et _al., 1952). Hungate ( 1942) showed that holotrichs readily utilized glucose, fructose, sucrose, galactose, cello biose, inulin and levan. Sugden (1953) and Hungate (1943)

Selenium and sulfur nutrition of beef cattle

“…Although these are limited observa tions, they would suggest that the sulfur effect in the pre sent studies was not on the protozoa. Christiansen (1963) has observed with lambs that high concentrate ground rations and high levels of feed intake tend to decrease the pro tozoal population of the rumen. Since there was an increase in feed consumption with time in the trials reported here, it is likely that there was a depletion of the protozoal population in these animals.…”