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Öğe Assessment of amino acid requirements for optimum fermentation of xylan by mixed micro-organisms from the sheep rumen(2005) Guliye, A.Y.; Atasoglu, C.; Wallace, R.J.A deletion approach was undertaken to identify which amino acids (AA) most limited the growth of mixed ruminal micro-organisms on xylan. Ruminal fluid was withdrawn from sheep receiving a mixed grass hay/concentrate diet and incubated for 24 h with oat spelts xylan in the presence or absence of a mixture of 20 AA or the same mixture with a single AA deleted. Gas and volatile fatty acid production were increased by the AA mixture in comparison with incubations in which ammonia was the only added nitrogen (N) source, and the deletion of each of the aromatic AA, tyrosine, phenylalanine and tryptophan, as well as leucine and methionine, led to decreases (P <0.05) in fermentation rate. The addition of aromatic AA as a mixture to ammonia-only fermentations increased (P <0.05) the fermentation rate but failed to replicate the benefits of the complete mixture of AA. Although the addition of all 20 AA increased (P <0.05) the microbial yield by up to 0.56, no single AA deletion had a significant (P >0.05) influence on microbial yield, and the aromatic AA mixture also did not increase the microbial yield on xylan over the yield with ammonia as sole N source. It was concluded that aromatic AA may be first-limiting for xylan fermentation, but they cannot replace the benefits of a complete mixture of 20 AA in stimulating xylan fermentation by ruminal micro-organisms. © 2005 British Society of Animal Science.Öğe Effects of kefir as a probiotic source on the performance of goat kids(South African Journal Of Animal Sciences, 2010) Atasoglu, C.; Akbag, H. I.; Tolu, C.; Das, G.; Savas, T.; Yurtman, I. Y.Kefir is a sour, viscous, slightly carbonated and alcoholic milk beverage, which is traditionally fermented using a culture of bacteria and yeasts. The influence of kefir on health has been well studied in mice and rats. However, research on kefir use in ruminants is rather limited. The aim of this study was to investigate the effect of kefir as a probiotic on the performance of goat kids during the pre- (45 days) and post-weaning (45 days) periods. Forty eight kids were randomly allocated to four treatment groups: Control, Kefir, Auto-Kefir (autoclaved) and Probiotic (a commercial probiotic). The kids were weaned at 45 days of age. The supplementation of different probiotics did not have any significant effect throughout the study on live weight and weight gain of the kids as compared to the Control group. Milk intake or milk-based nutrient intake of kids did not differ significantly among treatments in the pre-weaning period. Similarly, the intake of concentrate feed and nutrients from the concentrate was not affected by the treatments during post-weaning. No significant differences in faecal consistency of kids were found among the treatments. The results of the study indicated that supplementation of kefir as a natural probiotic or a commercial probiotic source does not improve performance of goat kids under the conditions in the present study and suggest that new approaches are required for studying the efficacy of this probiotic.Öğe In vitro fermentation of different starches by mixed micro-organisms from the sheep rumen(Blackwell Publishing, 2007) Atasoglu, C.; Yurtman, I. Y.Fermentation characteristics of wheat, rye, maize and triticale starches by mixed micro-organisms from the sheep rumen were determined in an in vitro experiment. Starch was incubated with ruminal fluid for 2, 4, 6, 8, 10 and 12 h and various fermentation variables were determined. The rates of fermentation of the starches were not different (p > 0.05) from each other except for 2 and 4 h of incubation. Likewise, net ammonia production, sugar utilization, microbial biomass and the efficiency of microbial protein synthesis did not differ between the starches (p > 0.05). The proportions of sugar utilized were similar between the starches and approximately 75% of the starches were fermented during the 12-h incubation. The 12-h net concentrations of individual and total volatile fatty acids (VFA) were affected (p < 0.05) by the type of starch. The concentrations of acetate, propionate and butyrate and that of total VFA from wheat, maize and triticale incubations were higher (p < 0.05) than those from rye incubation. The results suggest that the type of starch subject to investigation had no measurable effects on fermentation variables determined in this study except for individual and total VFA concentrations.Öğe Mode of action of Chrysanthemum coronarium as a modulator of biohydrogenation of fatty acids in the rumen(Brill, 2023) Morales, E. Ramos; McKain, N.; Atasoglu, C.; Wood, T.A.; Wallace, R.J.[No abstract available]Öğe Use of stable isotopes to measure de novo synthesis and turnover of amino acid-C and -N in mixed micro-organisms from the sheep rumen in vitro(2004) Atasoglu, C.; Guliye, A.Y.; Wallace, R.J.Protein synthesis and turnover in ruminal micro-organisms were assessed by stable-isotope methods in order to follow independently the fate of amino acid (AA)-C and -N in different AA. Rumen fluid taken from sheep receiving a grass hay-concentrate diet were strained and incubated in vitro with starch-cellobiose-xylose in the presence of NH3 and 5 g algal protein hydrolysate (APH)/l, in incubations where the labels were 15NH3, [15N]APH or [13C]APH. Total 15N incorporation was calculated from separate incubations with 15NH3 and [15N]APH, and net N synthesis from the increase in AA in protein-bound material. The large difference between total and net AA synthesis indicated that substantial turnover of microbial protein occurred, averaging 3.5 %/h. Soluble AA-N was incorporated on average more extensively than soluble AA-C (70 v. 50 % respectively, P=0.001); however, incorporation of individual AA varied. Ninety percent of phenylalanine-C was derived from the C-skeleton of soluble AA, whereas the incorporation of phenylalanine-N was 72 %. In contrast, only 15 % aspartate-C + asparagine-C was incorporated, while 45 % aspartate-N + asparagine-N was incorporated. Deconvolution analysis of mass spectra indicated substantial exchange of carboxyl groups in several AA before incorporation and a condensation of unidentified C2 and C4 intermediates during isoleucine metabolism. The present results demonstrate that differential labelling with stable isotopes is a way in which fluxes of AA synthesis and degradation, their biosynthetic routes, and separate fates of AA-C and -N can be determined in a mixed microbial population. © The Authors 2004.
