Substrates enriched by the fungus Cunninghamella echinulata: an in vitro study of nutrient composition, sheep rumen fermentation and lipid metabolism.

AIMS: Enrichment of wheat bran (WB), corn meal (CM) and barley flakes (BF) with the oleaginous fungus Cunninghamella echinulata (CE) might lead to effective use of these by-products in ruminant nutrition. We examined their effects on rumen fermentation and lipid metabolism. METHODS AND RESULTS: WB, CM and BF substrates without or with brewer's grains (WBG, CMG, BFG) and enriched with CE were incubated with meadow hay (MH, 500 : 500, w/w) in rumen fluid in vitro for 24 h. The dry matter of the CE-enriched substrates increased (by 2-4%); however, digestibility decreased (P < 0·01). Adverse effects of CE-enriched substrates on the rumen ciliate population were observed. Little effect on the rumen eubacterial population was detected by the 16S-polymerase chain reaction/denaturizing gradient gel electrophoresis method. The increase in γ-linolenic acid output in the MH + BFGCE diet (800 : 200, w/w) was accompanied by an increase in rumen biohydrogenation of polyunsaturated fatty acids. CONCLUSION: The diet substrates enriched with the fungus CE were less digestible than the untreated cereal substrates; no appreciable positive effect was observed on rumen fermentation patterns or the eubacterial and ciliate populations. SIGNIFICANCE AND IMPACT OF THE STUDY: The in vitro study showed that adding CE-enriched substrates to ruminant diets is not effective for improving rumen fermentation.

Effects of prefermented cereal-derived substrates (ground barley and rye bran) enriched with fungal γ-linolenic acid on rumen fermentation parameters and lipid metabolism in vitro.

AIMS: To increase rumen output of γ-linolenic acid (GLA), we used two cereal-derived substrates, ground barley (GB) and rye bran (RB), enriched with fungal GLA as components of feed rations. We examined their effects on rumen fermentation patterns, lipid metabolism and the ciliated protozoan population in an artificial rumen. METHODS AND RESULTS: Four diets consisting of meadow hay (MH) plus unfermented (GB or RB) or prefermented (GB - TE or RB - TE) cereal-derived substrates were fermented in an artificial rumen with ovine rumen inoculum. The cereal-derived substrates were prefermented with the fungus Thamnidium elegans (TE) by fungal solid-state fermentation. The diets with TE increased the rumen input of dietary GLA (mg day(-1)) from 0 to 21 (GB - TE) or 26 (RB - TE). Both experimental diets increased the rumen output of GLA (P < 0.001). Adverse effects on the ciliate population were observed. Both diets also had an effect on the fatty acids profile. Fermentation patterns were also affected with MH + RB - TE. CONCLUSION: Cereal-derived substrates enriched with GLA effectively enhanced the output of GLA in artificial rumen. SIGNIFICANCE AND IMPACT OF THE STUDY: The ability of the fungal strain T. elegans to grow and utilize various agro-industrial substrates might be useful in developing potential new animal diets enriched in GLA.

Comparison of nisin and monensin effects on ciliate and selected bacterial populations in artificial rumen.

The effect of daily supplementation of nisin (2 mg/L), monensin (5.88 mg/L) and nisin and monensin (2 + 5.88 mg/L) on ovine ruminal ciliates and bacteria was investigated using the artificial rumen RUSITEC. Major groups in RUSITEC were Entodinium spp. and Dasytricha ruminantium. The supplementation of nisin significantly increased the population of both major ciliate groups. The supplementation of monensin significantly decreased the population of both groups. The combined effect of nisin and monensin was similar to the effect of monensin. Monensin had strong antiprotozoic effects in contrast to the stimulatory effects of nisin. D. ruminantium followed by Entodinium spp. appeared more resistant to tested compounds than other rumen ciliates. Tested additives did not significantly influence the presence and growth of amylolytic streptococci and enterococci but nisin showed a tendency to decreasing the concentration of Escherichia coli and lactobacilli.

Effect of plant oils and organic acids on rumen fermentation in vitro.

We determined the effect of plant oils (rapeseed, sunflower, linseed) and organic acids (aspartic and malic) on the fermentation of diet consisting of hay, barley and sugar beet molasses. Rumen fluid was collected from two sheep (Slovak Merino) fed with the same diet twice daily. Mixed rumen microorganisms were incubated in fermentation fluid, which contained rumen fluid and Mc Dougall's buffer. All supplemented diets significantly increased pH, molar proportion of propionate, and numerically decreased methane production. Lactate production was also decreased significantly (except with malate). Incorporation of plant oils into aspartate- and malate-treated incubations negated the decrease of butyrate, lactate and the increase of pH and ammonia with malate treatment, as well as in vitro dry matter digestibility and pH with aspartate treatment. The effect of combined additives on methane production and molar proportion of propionate was lower compared with additives supplemented separately. Combination of additives had no additive effect on rumen fermentation. All additives decreased total protozoan counts in rumen fluid.

Effect of nisin and monensin on rumen fermentation in the artificial rumen.

The objective of this study was to investigate the effect of nisin and monensin on rumen fermentation of diets containing hay and barley (80:20%) in artificial rumen (Rusitec system). The Rusitec system consisted of four fermentation vessels (V1, V2, V3, V4): V1 was without additives (control), V2 received daily 2 mg of nisin, V3 involved 5 mg of monensin and V4 combination of 2 mg of nisin with 5 mg of monensin. After an adaptation period (7 days), the fermentation parameters were determined for six consecutive days. Compared to control diet, the addition of nisin resulted in an increase (P < 0.05) of hemicellulose degradation, acetate, propionate (mmol.day-1) production and energetic efficiency of VFA (E), decrease of butyrate production. Nisin had no effect on dry matter (DM), organic matter (OM), cellulose and detergent fiber degradation, production of total gas, methane and efficiency of microbial synthesis. The addition of monensin resulted in an decrease of DM, OM (P < 0.05), cellulose, hemicellulose, detergent fiber degradation (P < 0.001), total gas, methane and ammonia nitrogen (NH3-N) production. Monensin also significantly decreased acetate, butyrate, L-lactate (mmol.day-1) production and it increased propionate production (P > 0.001) and efficiency of microbial synthesis. The combined effect of nisin and monensin in V4 was similar to the effect of monensin in V3 compared to control. Then, the effect of additive monensin was dominant over nisin. In conclusion, our results indicate that nisin was less effective than monensin on some fermentation parameters (important for the improvement of the efficiency of utilization of the diet by ruminants) in artificial rumen.

Effect of plant oils and aspartate on rumen fermentation in vitro.

The effect of plant oils and aspartate (ASP) on rumen fermentation in vitro. The objective of this study was to determine the effect of plant oils (rapeseed - RO, sunflower - SO; linseed - LO; 10% wt/wt) and 8 mmol sodium aspartate on rumen fermentation of a diet (250 mg) consisting of hay, barley and sugar beet molasses (60 : 30 : 10). Rumen fluid was collected from two Slovak Merino sheep fed the same diet twice daily. Mixed ruminal micro-organisms were incubated in fermentation fluid (40 ml) containing rumen fluid and McDougall's buffer (1 : 4). Incubations were carried out in batch cultures for 72 h at 39 degrees C two times in a 3-week intervals. When compared to the control, all supplemented diets (RO, SO, LO, ASP) significantly increased the pH, the mol% of propionate (LO + 8.7%; SO + 10.12%; RO + 8.65%; ASP + 5.86%) and the acetate : propionate ratio and numerically decreased methane production (SO -32.8%; LO, RO -30.08%; ASP -21.56%). Lactate production was also significantly decreased. Addition of plant oils to aspartate-treated incubations partly inhibited the decrease of n-butyrate, lactate and the increase of pH and in vitro dry matter digestibility (IVDMD) caused by ASP treatment. The effect of combined additives (RO + ASP, SO + ASP, LO + ASP) on methane production SO + ASP (-19.23%) and mol% propionate SO + ASP (+2.66%), LO + ASP (+4.28%) was less effective. All combined additives caused a significant decrease in digestibility of the given feeds. No effect of plant oils and ASP could be observed on the parameters of rumen fermentation (mainly methane and propionate).

Effect of yeast culture and phenolic acids on the physiology of rumen fermentation determined in vitro.

The effect of p-hydroxybenzoic acid (HBA), syringic acid (SYA) and yeast culture (YS) on rumen fermentation in vitro has been investigated. Meadow hay was used as a substrate and rumen fluid as an inocula. The yeast culture Levucel contained 5x10(8) yeast cells Saccharomyces cerevisiae per 1 g of dry matter and was used in the amount of 0.5 g/l of the medium. The following combinations of additives were used: hay without additive, hay + YS, hay with 1, 5 or 10 mmol HBA or SYA, and hay + YS with 1, 5 or 10 mmol HBA or SYA. The test tubes were incubated for 96 hours at 39 degrees C. The results showed that 1 mmol HBA had a significant effect on yeast efficacy. This was manifested in the increased degradability of hay dry matter (P <0.05) and enhanced total gas production (P<0.05). SYA in the same amount combined with yeast had a similar effect on gas production (P<0.05), but hay dry matter degradability was not affected. The results showed a slight effect of phenolic acids and yeast culture on hay rumen fermentation in vitro.

Effect of white-rot basidiomycetes-treated wheat straw on rumen fermentation in artificial rumen.

This study evaluated three white-rot basidiomycetes for their potential to improve the ruminal degradation of wheat straw. Pleurotus ostreatus (PO), Pleurotus ostreatus-mutant (PO-M) and Trametes gibbosa (TG) were incubated on wheat straw for 30 days at 28 degrees C. Neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein and in vitro dry matter digestibility (IVDMD) were determined. The results demonstrated increasing crude protein and ash contents (%) in the fungi-treated straws. The IVDMD values were also increased. Compared to untreated wheat straw (UWS), the NDF and ADF contents were reduced in fungi-treated straw (TWS). Out of the three fractions-hemicellulose, cellulose and lignin-hemicellulose showed the largest proportionate loss and lignin the smallest in all three fungi-treated straws. TWS with Pleurotus ostreatus (TWS-PO), Pleurotus ostreatus-mutant (TWS-PO-M) and Trametes gibbosa (TWS-TG) together with barley (80:20%) were used as the experimental diets in the artificial rumen. UWS with barley (80:20%) served as the control diet. The results revealed significantly higher IVDMD values, NDF, ADF and cellulose digestibilities (%) with the experimental diets. The production of propionic acid decreased, n-butyric, n-valeric and isovaleric acids (mmol/day-1) increased and the volatile fatty acid (VFA) production expressed in mol VFAs.kg-1 digested dry matter decreased in experimental diets. The total microbial production also decreased at fermentation in the experimental diets.

The effect of white-rot basidiomycetes on chemical composition and in vitro digestibility of wheat straw.

Five white-rot basidiomycetes were evaluated for their potential to improve ruminal degradation of wheat straw. Polyorus brumalis, Lyophyllum ulmarium III, Trametes gibbosa, Pleurotus ostreatus, and a Pleurotus ostreatus mutant were incubated on wheat straw for 30 d at 28 degrees C. Detergent fiber, crude protein and in vitro dry matter digestibility (IVDMD) were determined. The results showed increasing crude protein and ash contents in fungus-treated straw. IVDMD values were increased in straws treated with P. ostreatus, P. ostreatus mutant and T. gibbosa only. Relative to untreated wheat straw the detergent fiber content-neutral detergent fiber (NDF), and acid detergent fiber (ADF) was reduced in fungus-treated straw and out of three fractions-hemicellulose, cellulose, and lignin, hemicellulose showed the largest proportionate loss whereas lignin the smallest one in all 5 samples of fungus treated straw.

[The effect of cadmium on the protozoan population and rumen fermentation of feed in an artificial rumen]. / Vplyv kadmia na protozoárnu populáciu a bachorovú fermentáciu krmnej dávky v umelom bachore.

In our experiment, the effects of 5, 10 and 20 mg cadmium per kg dry matter (DM) on protozoan population and rumen fermentation of feed ration consisting of 11.7 g DM of hay and 2.8 g DM of barley (80: 20%) were followed in artificial rumen (Rusitec). The results of the experiment showed that the addition of 5 and 10 mg cadmium per kg DM less significantly (P < 0.05) decreased the digestibility of DM, organic matter and neutral detergent fibre and significantly (P < 0.01) decreased the digestibility of cellulose of feed ration. It is interesting that the addition of 20 mg cadmium per kg DM did not influence these parameters. Although the total gas production showed a tendency of decrease due to the influence of the addition of 5, 10 and 20 mg cadmium/kg DM, methane and CO2 production was not altered. However, cadmium significantly influenced the production of individual volatile fatty acids-VFA's (mmol/day). The addition of 5, 10 and 20 mg cadmium per kg DM significantly increased acetic acid production (by 10-20%) and decreased propionic acid production (by 18-30%). Therefore, the acetate: propionate ratio was significantly increased (from 1.57 to 2.45-2.60) by the addition of cadmium. The production of n-valeric and iso-valeric acids was also significantly decreased in comparison with the control. The decrease of individual VFA's was more significant at the higher amount of cadmium added into the fermentation system. The proportions of individual VFA's in total VFA production expressed in molar % showed a similar character. The changes in the production of individual VFA's due to the influence of the addition of 5, 10 and 20 mg cadmium per kg DM caused a decrease in energetic efficiency of VFA's (P < 0.001) in comparison with the control. The other parameters of rumen fermentation - utilization of glucose, adenosine triphosphate (ATP) production, fermented hexose, fermented amino acids and fermented organic matter (OMF) were not influenced by the cadmium addition. Although the total microbial matter production in effluent and undigested feed (residues) was significantly (P < 0.001) decreased by the addition of 5, 10 and 20 mg cadmium per kg DM, the efficiency of microbial synthesis expressed as YATP and g microbial N/kg OMF was not changed and achieved the values 11.78-12.68 (YATP), 25.56-28.35 (g microbial N/kg OMF), respectively. The total protozoan population was significantly decreased by the cadmium addition mainly as a result of the decrease of infusoria of Entodinium spp.(ABSTRACT TRUNCATED AT 400 WORDS)

Influence of Rhaponticum carthamoides Wild on the growth of ruminal bacteria in vitro and on fermentation in an artificial rumen (Rusitec).

The fermentation of a basal diet composed of hay and barley (80:20%) was compared with fermentation of three rations in which 5 and 10% of hay and 10% of basal diet were replaced with the above-ground part of Rhaponticum carthamoides Wild in an artificial rumen (Rusitec). Results of 14 days experiments indicated that the digestibility of dry matter, organic matter, detergent fibre, production of CO2 and methane, NH3-N in effluent and total and individual VFA (mmol/day) were not affected in the process of fermentation of experimental diets in comparison with the basal diet. Addition of Rhaponticum carthamoides did not modify the production, utilization and recovery of metabolic hydrogen, glucose utilization, ATP production, YATP and effectiveness of microbial biomass synthesis expressed in g of microbial N/kg of organic fermented biomass. Water extracts of Rhaponticum carthamoides had no influence on growth parameters of a mixed culture of rumen bacteria. Overall results of this experiment indicated that the above-ground part of Rhaponticum carthomoides fully replaced the 5 and 10% portions of hay or 10% portion of the whole diet.

[The effect of defaunation on fermentation in vitro]. / Vplyv defaunácie na fermentáciu in vitro.

An experiment was conducted to investigate the effects of defaunation on the fermentation of two different diets consisting of hay (100%) and hay+barley (80% + +20%) in a rumen pouch (RUSITEC). The survival and composition of protozoa were investigated in an in vitro system in control vessels where no defaunation was carried out. Defaunation decreased the production of total volatile fatty acids (P < < 0.01), acetate, butyrate (P < 0.001)--Tab. II; dry matter digestibility (P < 0.05) and detergent fibre digestibility: acid detergent fibre (ADF), neutral detergent fibre (NDF), cellulose (P < 0.001), hemicellulose (P < 0.01 and P < 0.001, respectively) in our experiment (Tab. I). These parameters also decreased: production of CH4 (P < 0.001), CO2 (P < 0.01 for the barley diet), total production of gases (P < 0.001 for the barley diet), total utilization (P < 0.01 and P < 0.001, respectively) and recovery of H2 (P < 0.05 and P < 0.001, respectively), NH3-N in effluent (P < 0.001 and P < 0.01, respectively)--Tab. III; and production of ATP (P < 0.01)--Tab. IV, as a result of fermentation in our experiment. On the other hand, there was a significant increase in the following parameters: production of propionate (P < 0.001 for the barley diet)--Tab. II; microbial nitrogen/kg of organic matter fermented--OMF (P < 0.001), Tab. III; energy yield--E of volatile fatty acids (VFA), proportion of VFA energy with respect to fermented hexose energy--E1, proportion of energy in bacterial cells with respect to fermented hexose energy--E3 (P < 0.001) and the effectiveness of microbial proteosynthesis--YATP (P < 0.001), Tab. IV, as a result of defaunation. The total number of protozoa and the number of some species, especially the number of big entodinio-morphid protozoa, were markedly higher (p < 0.001) for the barley diet--Tab. V. The number of protozoa decreased rapidly within three days after the system initiation. Later on, the values were more or less steady.

[The effect of copper and cobalt supplementation on the digestibility of fibrous feed in sheep]. / Vplyv prídavku medi a kobaltu na strávitel'nost fibróznych krmiv u oviec.

The effects of an addition of copper, cobalt, and copper + cobalt on the in vitro digestibility of hay, treated beech sawdust and cellulose by the rumen fluid of sheep fed a complete food ration, complete food ration with 15% treated beech sawdust and a diet consisting of 80% hay and 20% barley were investigated, respectively. The rumen fluid obtained from animals fed a complete food ration showed the significantly higher digestibility of hay (Tab. I) when Cu (P less than 0.05), Co, or Cu + Co (P less than 0.001) had been added into the rumen. The cellulose digestibility increased only after Co application (P less than 0.05). The microelements supplementation in all three forms had a very significant effect on the digestibility of treated beech sawdust by the rumen fluid of sheep fed a diet with 15% sawdust content, although the initial digestibility by the rumen fluid in the control animals (without microelements) was only 44.9%. A similar trend was also observed in the cellulose digestibility, but after Co application this increase was not significant. The rumen fluid of animals fed hay (80%) and barley (20%) showed the highest digestibility. The digestibility of sawdust reached 60% and the of cellulose 95.9% without microelements supplementation (control). In this case the effect of microelement supplementation on the sawdust digestibility was manifested only in the case of cobalt by the digestibility decrease (P less than 0.001). The cellulose digestibility also decreased after administration of Cu (P less than 0.01) and Co (P less than 0.05). The Cu + Co supplementation did not influence its digestibility.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of monensin (USA, Czechoslovakia, Bulgaria) on fermentation of animal feed in an artificial rumen (Rusitec)]. / Efektívnost vplyvu monenzínu (USA, CSFR, Bulharsko) na fermentáciu krmnej dávky v umelom bachore (Rusitec).

An experiment was made with the Rumen Simulation Technique (Rusitec) in which the fermentation of a mixed ration of hay (12.8 g/d) and bruised barley (3.2 g/d) was compared with the fermentation of the same diet in the presence of 5 mg monensin/d from the USA, CSFR and Bulgaria. The fermentation of the mixed ration was significantly affected by all three kinds of monensin. The digestibility of dry matter (DM) in the rations declined in the presence of monensin from 48% to 40% (tab. I). The digestibility of detergent fibre, cellulose and hemicellulose also declined in the presence of monensin (tab. I). The production of methane decreased (-70%) and CO2 production dropped too, but this decrease could be accounted for by the changes in the production of volatile fatty acids and redistribution of metabolic hydrogen (tab. I). Monensin decreased the production of total volatile fatty acids (-21%), the production of acetic (-35%), n-butyric, n-valeric and isovaleric acids (tab. II) and increased the production of propionic acid (+60%). The production, utilization and recovery of metabolic hydrogen were significantly increased in the presence of all three kinds of monensin (tab. IV). The end products of fermentation were affected by an addition of monensin to the mixed ration. All three kinds of monensin increased energic efficiency of volatile fatty acids, decreased adenosinetriphosphate (ATP) production, the amounts of fermented hexose, organic matter fermented and utilization of glucose (tab. III).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of monensin on fermentation of hay and wheat bran investigated by the Rumen Simulation Technique (Rusitec). 1. Basal parameters of fermentation.

An experiment was performed with Rumen Simulation Technique (Rusitec) in which the fermentation of mixed ration of hay (12.8 g/d) and wheat bran (3.2 g/d) was compared with the fermentation of the same diet in the presence of 2, 5 and 10 mg of monensin/d. The duration of the experiment was 12 days. During the first six days the fermentation conditions in Rusitec were stabilized. Monensin significantly depressed the digestibility of dry matter and fibre digestion--neutral detergent fibre (NDF), acid detergent fibre (ADF) and cellulose but only after using 2 mg monensin/d. Addition of monensin depressed the production of VFAs--acetate, butyrate and isovalerate and acetate:propionate ratio. Production of propionate was increased and production of methane and CO2 was decreased in the presence of monensin. It can be explained by changes in the production of VFAs and redistribution of metabolic hydrogen. The recovery of nitrogen was satisfactory (about 100%) and its distribution in the effluent was increased by monensin. The recovery of protein (measured as alpha--NH2 groups) and distribution of protein in the effluent and residues was increased with the increasing dose of monensin.

Effect of monensin on fermentation of hay and wheat bran investigated by the Rumen Simulation Technique (Rusitec). 2. End-products of fermentation and protein synthesis.

An experiment was performed with Rumen Simulation Technique (Rusitec) in which the fermentation of mixed ration of hay (12.8 g/d) and wheat bran (3.2 g/d) was compared with the fermentation of the same diet supplemented with 2.5 and 10 mg monensin. The duration of the experiment was 12 days. During the first six days the fermentation conditions in Rusitec were stabilised. The end products of fermentation and indices of protein synthesis were determined. The energy efficiency of volatile fatty acids (VFA), proportion of fermented hexose energy on VFA energy and on energy of bacterial matter were increased in the presence of monensin. The proportion of fermented hexose energy in methane energy was decreased. Utilization of glucose and production of adenosine triphosphate were not affected. The balance of metabolic H2 was reduced and this was manifested in decreasing production, utilization and recovery of metabolic H2. Microbial efficiency expressed per mol ATP (g/mol) was increased by monensin from 7.8 to 12.6. The indices of protein synthesis--protein conversion ratio, degradability of protein and microbial protein synthesis efficiency were increased and non protein utilization ratio decreased in the presence of monensin.

[The effect of monensin on the fermentation of feed with different proportions of hay and concentrate in an artificial rumen (rumen simulation technic)]. / Vplyv monenzínu na fermentáciu diét s rôznym podielom sena a koncentrátu v umelom bachore (Rusitec).

An experiment was conducted with rumen pouch (RUSITEC--Rumen Simulation Technique). In four fermentation vessels (V), percent proportions of hay and barley were as follows: V1--40:60, V2 - 60:40, V3--80:20 and V4--100:0. Every day 5 mg of monensin dissolved in 1 ml 96% ethanol were added to each fermentation vessel. All diets were isonitrogenous, and after an addition of urea the crude protein (CP) content made 13% in each diet. The experiment lasted 12 days: so called steady state period took the first six days when the fermentation conditions were stabilized. Monensin reduced dry matter digestibility, production of total volatile fatty acids, acetic acid, n-butyric and isovaleric acids and acetate: propionate proportion, and it increased the production of propionic and n-valeric acids. The production of methane and CO2 decreased. The higher proportion of hay in diets decreased dry matter digestibility, digestibility of detergent fibre, total and individual volatile fatty acids, CO2, methane energy yield of volatile fatty acids (E), glucose utilization, production of adenosine triphosphate and production of fermented hexoses. The production, utilization and recovery of metabolic hydrogen also decreased. The effectiveness of microbial matter synthesis (YATP = 11.3) was highest during the fermentation of feed containing 60% hay and 40% barley.

[The effect of methanol extracts of sawdust on the digestion of cellulose, hay and wheat bran in vitro]. / Vplyv metanolového extraktu pilín na trávenie celulózy, sena a psenicných otrúb in vitro.

An experiment was treated to investigate the effects of an extract of conditioned beech sawdust (80% methanol extraction) on the in vitro digestion of cellulose and on the digestion of hay and wheat bran diet (80 to 20%) in a artificial rumen (Rusitec). The addition of 10, 25, 50, 75 mg of extract to 0.25 g cellulose reduced significantly its digestibility from 94.5 to 92.9%; 90.4; 85.2; 82.1 and 80.1%, respectively. The addition of 0.6, 1.5 and 3.0 g of extract to 14 g diet DM in Rusitec decreased the digestibility from 49.6 to 41.8%. Gas (CO2, H2, CH4) production increased as well as the production of total volatile fatty acids: acetic, propionic, n-butyric and isobutyric, glucose utilization and ATP production were also better. The addition of extracts did not influence significantly the effectiveness of microbial proteosynthesis (YATP). The methanol extract of conditioned beech sawdust contained reducing sugars (saccharides), besides the phenolic substances (syringaldehyde and vanillin); these sugars influenced diet fermentation in Rusitec.

[The effect of citronellylseneciate on the utilization of feed in sheep]. / Vplyv citronelylseneciátu na vyuzitie krmiva u oviec.

The influence of citronellylseneciate on the digestibility of nutrients and energy, as well as on the level of some rumen and blood metabolites, was studied in feed rations for rams. Citronellylseneciate was not found to have a significant influence on the digestibility of nutrients and energy and nitrogen balance in feed ration. Neither did citronellylseneciate influence the production of total volatile fatty acids and the molar percent of acetic, propionic and n-butyric acids. The addition of citronellylseneciate to feed ration resulted in a decrease in the pH value in rumen and in a non-significant increase in ammonia in rumen and urea in blood. The hematological profile showed increased levels of phosphorus and glutamate-oxalate transferase.

[Volatile fatty acids in the rumen of sheep fed a synthetic diet]. / Unikavé mastné kyseliny v bachore oviec krmených syntetickou diétou.

A trial was conducted with wethers to study the effect of the administration of a synthetic diet (composition: 30.125% starch, 30.125% sucrose, 25% cellulose, 5.25% urea, 8.125% mineral supplement, 1.25% maize oil and 0.125% cholinechloride) upon rumen fermentation. The adaptation to the synthetic diet lasted three months, the proportion of the synthetic diet increasing every week (by 10%) to the detriment of a traditional diet (composition: 0.5 kg meadow hay, 0.3 kg barley, 0.2 kg wheat bran, salt and straw ad libitum). In the 10th week the animals consumed 0.5 kg granular synthetic diet, 0.2 kg cellulose flakes and 0.01 kg polystyrene. After three weeks of the administration of the fully synthetic diet, the rumen fluid was sampled after morning feeding in intervals of 0, 1, 3, 5 and 7 hours. In the dynamics of fermentation, statistically significant differences were found only in isobutyric and isovaleric acid between the 0th and 1st and between the 5th and 7th hours (P less than 0.05--P less than 0.001). The data for all the time intervals were recalculated to average values. These were as follows: total volatile fatty acids 63.03 mmol/l, acetic acid 51.00 mol%, propionic acid 26.75 mol%, butyric acid 19.43 mol%, isobutyric acid 0.91 mol%, isovaleric 1.27 mol%, valeric acid 0.62 mol%, energy efficiency of VFA production 78.23%. The obtained data are confronted with literary data on synthetic diets which contained urea and various energy sources.