Effect on rumen microbial populations of ammonia treatment of rice straw forage for steers.

Abstract

The microbial populations and fermentation characteristics were compared in the rumina of two rumen-cannulated Holstein steers fed untreated rice straw (RS) and concentrate or ammonia-treated rice straw (ARS) and concentrate. The total volatile fatty acid concentrations in the rumina of both steers were significantly higher when they were fed ARS than when fed RS. The molar proportion of butyric acid when ARS was fed increased significantly, compared with the periods when was fed RS. The population density of protozoa varied only insignificantly with RS or ARS diets. But Dasytricha spp. increased with RS and Entodinium spp. increased with ARS. The viable counts of cellulolytic bacteria were higher with ARS than with RS. The viable counts of sulfate reducing bacteria were lower with ARS, compared with the RS diet. Feeding ARS increased the viable bacterial populations such as Eubacterium spp., Fibrobacter succinogenes, Ruminococcus albus, and Succinivibrio spp. But Bacteroides spp. and Butyrivibrio spp. were dominant when RS was fed.Various physical and chemical treatments of low-quality roughages to improve their nutritive values for ruminants have been tried (11,21). Such physical treatments as grinding, milling and chopping have increased the intake of roughages, but has not improved their nutritive value. Moreover, these treatments had the disadvantage of high costs. On the other hand, chemical treatment with calcium hydroxide, sodium hydroxide or ammonia has been tried to improve their nutritive values and to avoid spoilage during storage. Of the treatments with alkali, the ammonia treatment has the advantages of being relatively inexpensive, simply applied on the farm, and it increases the digestibility and the nitrogen content of the herbage. The

Colonization of microorganisms in the rumen of young calves.

“…The methods of counting such functional groups of bacteria as cellulolytic bacteria, amylolytic bacteria, xylan-fermenters, pectin-fermenters, lactate-utilizers, sulfate-reducing bacteria and methanogens were the same as those described previously (9,12) .…”

“…The remaining portion of the samples was stored in a refrigerator following acidification with 24% (w/v) meta-phosphoric acid in 5 N HZSO4, for VFA analysis. The VFA in samples was analyzed by gas chromatography according to the methods described previously (12).…”

“…Total viable counts of anaerobic bacteria in the samples were made by the techniques of Hungate (8) with RGCMSA medium described previously (12).…”

“…Samples of the rumen contents were transported immediately to a laboratory. For the determination of viable counts of both aerobic and anaerobic bacteria, tenfold serial dilutions were prepared in the anaerobic dilution solution described previously (12).…”

Influence of the presence of protozoa on the rumen microbial population of cattle.

“…The rumen content containing solids and liquid portions was processed according to the procedures described in the previous report (17). The homogenized rumen content was strained through one layer of gauze.…”