A semi-synthetic thiamine-free diet was used on weaned lambs to test the effect of a high sulfur level on the rumen, microbial activity and on the microbial production of thiamine. In vivo and in vitro kinetic studies, as well as the determination of the thiamine concentrations and thiaminase activity in the rumen, were performed during the 16 week experiment. A high sulfur level (0.6%) in the ...

BACKGROUND Ureolytic activity of rumen bacteria leads to rapid urea conversion to ammonia in the rumen of dairy cows, resulting possible toxicity, excessive ammonia excretion to the environment, and poor nitrogen utilization. The present study investigated immunization of dairy cows against urease in the rumen as an approach to mitigate bacterial ureolytic activity therein. RESULTS Most alpha...

Members of the domain Archaea contribute about 0.3 to 3.3% of the microbial small subunit (16S and 18S) rRNA in the rumen (22, 39, 60). Archaea have a range of different metabolisms and are found in many habitats (6), but those known to exist in the rumen are strictly anaerobic methanogens. Yanagita et al. (59) observed that 2.8 to 4.0% of ruminal microorganisms displayed autofluorescence chara...

ruminal bacteria and protozoa provide excellent organic phosphorus (p) sources for the host animal. this experiment was conducted to compare the bioavailability of bacterial and protozoal p in comparison with that of dicalcium phosphate (dcp) as a reference phosphorus source. bacteria and protozoa were isolated from the rumen contents of dairy cows and the chick-model was used to determine the ...

Ruminants in tropical and desert areas routinely experience cycles of severe dehydration and rapid rehydration. These animals can withstand severe dehydration (18-40% of initial body weight), which exceeds considerably the capacity of most monogastric mammals. This capacity is related to their ability to use, during the course of dehydration, their large water reservoir in the rumen, which cont...

Çalışmada, Görüntü İşleme Metotları kullanarak Siyah Alaca süt sığırlarının vücut ölçülerinin ortaya konması, elde edilen birbirlerine bölünerek oranlar edilmesi ve bu oranların verim özellikleri ile ilişkilerinin konması amaçlanmıştır. Bu amaçla 198 büyük baş sığırının Sabit Nesne Video Metodu yardımıyla ölçüleri tespit edilmiştir. Tespit edilmiş Günlük Ortalama Süt Verimi (GOSV), Gebelik Başı...

Isotopic tracer experiments were conducted in vitro to determine contribution of protozoa toward the biosynthesis of lysine in the rumen microbial ecosystem. The presence of protozoa in a rumen microbial suspension always increased lysine synthesis from aspartate. Rumen contents from a faunated goat produced a higher amount of lysine than did those from a defaunated one.

Ureolytic bacteria are key organisms in the rumen producing urease enzymes to catalyze the breakdown of urea to ammonia for the synthesis of microbial protein. However, little is known about the diversity and distribution of rumen ureolytic microorganisms. The urease gene (ureC) has been the target gene of choice for analysis of the urea-degrading microorganisms in various environments. In this...

It is now generally accepted that the fermentation of carbohydrates in the rumen gives rise to the formation of large amounts of the lower volatile fatty acids; but the fact that these acids are absorbed in considerable amounts and at different rates from the rumen into the blood stream has made it clear that in vitro studies of the fermentation processes are necessary in order to ascertain the...