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Biomedical subjects

K Männer

Publications and source records attributed to K Männer.

At least 19 recordsLinked to original sources
PubMed2006

Weaning pig performance and faecal microbiota with and without in-feed addition of rare earth elements.

Two 6-week feeding trials were conducted on a total of 112 newly weaned piglets to examine the recently reported growth promoting effects of dietary rare earth elements (REE) in European pig production. Rare earth element-diets were supplemented with a REE-citrate premix of lanthanum and the light lanthanoides cerium, praseodymium and neodymium at 200 mg/kg for 6 weeks after weaning. Overall for both trials, growth performance of REE-citrate and control fed piglets did not differ significantly (p > 0.05). An early enhancive tendency for REE-citrate in trial 1 (feed conversion ratio, FCR -3%, p = 0.15) proved irreproducible in trial 2. In the late period of trial 1, in-feed addition of REE-citrate significantly impaired piglet performance (FCR + 8%, p = 0.01). A cultivation-independent molecular approach, polymerase chain reaction-denaturing gradient gel electrophoresis was further applied to assess REE induced alterations in the predominant faecal microbiota from weaning pigs. Calculation of various ecological characteristics does not indicate (p > 0.05) an often discussed selective effect on local microbial composition of dietary REE.

Animal Feed↗
PubMed2003

The effect of a probiotic Enterococcus faecium product in diets of healthy dogs on bacteriological counts of Salmonella spp., Campylobacter spp. and Clostridium spp. in faeces.

An experiment was conducted to determine the effects of a probiotic on selected faecal bacteria of healthy dogs under different feed and environmental conditions. For the study 12 dogs kept in households were used for an 18-day supplementation with a patented commercially available strain of E. faecium NCIB 10415 (Enteroferm). In order to minimize losses the probiotic product was orally applicated once a day before meals at a dose of 2 g per dog (9.2 x 10(9) CFU). The faeces were collected before the beginning of the supplementation and at the end of the 18-day application period. In order to exclude contamination, all faeces were taken rectally. Before and at the end of the experimental period total Salmonella spp., Campylobacter spp. and Clostridium spp. counts were determined in fresh faeces using selective media. It was demonstrated that the 18-day application of the probiotic E. faecium product induced modifications on the gastrointestinal microflora in all dogs. While Salmonella spp. and Campylobacter spp. counts were in majority of the dogs higher than before the application. Clostridium spp. counts were significantly reduced in 10 of 12 dogs. According to the guidelines for the evaluation of the efficiency of microorganisms in dogs a relevant efficacy effect was supported by this data. However, a beneficial effect of the probiotic product on healthy dogs remains questionable.

Administration, Oral↗
PubMed2001

Incorporation of dietary linoleic and conjugated linoleic acids and related effects on eggs of laying hens.

In the present study, laying hens received 29 g per kg diet of a preparation containing either 70% linoleic acid (LA) or approximately the same amount of conjugated linoleic acid (CLA) in the control and experimental treatments, respectively. The CLA preparation consisted predominantly of cis-9,trans-11 and trans-10,cis-12 fatty acid isomers as free fatty acids in a ratio of 1:1. The diets were fed for 8 wk to determine the effect of dietary CLA on quality characteristics of eggs. In addition, the fatty acid composition of liver and heart was analyzed. Performance parameters (egg weight, feed efficiency) were not significantly affected by feeding the diets supplemented with CLA. The overall amount of CLA that was incorporated into yolk was 7.95 g CLA/100 g total fatty acids, or approximately 400 mg CLA/egg. The transfer efficiency of the cis-9,trans-11 isomer was higher than that of the trans-10,cis-12 isomer; however, the transfer rate of CLA isomers into yolk and tissues was significantly lower than that of linoleic acid. Dietary CLA increased the concentration of saturated fatty acids in yolk and tissues at the expense of monounsaturated fatty acids. The proportions of myristic, palmitic, and stearic acids in yolk lipids were also changed by dietary CLA. Additionally, long-chain polyunsaturated fatty acids (arachidonic acid and docosahexaenoic acid) were decreased without changing the balance of the n-6/n-3 ratio in egg yolk. The inclusion of CLA in layer diets altered the shape of the yolk and various egg parameters (albumen height, foam index, and yolk index). The results of this study indicate that CLA induces various changes in lipid and fatty acid metabolism of laying hens and affects quality characteristics of eggs.

Animal Feed↗
PubMed2001

The effectiveness of an Escherichia coli phytase in improving phosphorus and calcium bioavailabilities in poultry and young pigs.

The effectiveness of an Escherichia coli phytase in comparison with a commercially available Aspergillus phytase in improving the bioavailability of phosphorus in broilers, layers and young pigs was studied in three separate experiments. Three basal diets, marginally deficient in dietary P mainly provided as phytate, were formulated. Both phytases were added to the diets at the rate of 500 U/kg diet. The phytases significantly (P < or = 0.05) improved the availability of phytate P to broilers, layers and young pigs. Aspergillus and E. coli phytases enhanced the pre-caecal digestibility of P by 11 and 29% for broilers and 18 and 25% for layers, respectively. Total tract digestibility of P (P balance) was also enhanced but with smaller magnitude. In pigs, total tract digestibility of P was improved by 33 and 34% by Aspergillus and E. coli phytases, respectively. Under the conditions of this study, it was observed that E. coli consistently, though with small magnitude in layers and pigs, enhanced the availability of phytate P at the same range or slightly better than Aspergillus phytase. It was only in pigs that the availability of Ca was significantly (P < or = 0.05) improved by addition of both phytases. It can be concluded that E. coli phytase is highly effective in improving the bioavailability of phytate P to broilers, layers and young pigs. This seems to be based on the high proteolytic stability of the enzyme in the digestive tract, as shown recently.

6-Phytase↗
PubMed2000

Comparative studies on the in vitro properties of phytases from various microbial origins.

The physical and chemical properties of six crude phytase preparations were compared. Four of these enzymes (Aspergillus A, Aspergillus R, Peniophora and Aspergillus T) were produced at commercial scale for the use as feed additives while the other two (E. coli and Bacillus) were produced at laboratory scale. The encoding genes of the enzymes were from different microbial origins (4 of fungal origin and 2 of bacterial origin, i.e., E. coli and Bacillus phytases). One of the fungal phytases (Aspergillus R) was expressed in transgenic rape. The enzymes were studied for their pH behaviour, temperature optimum and stability and resistance to protease inactivation. The phytases were found to exhibit different properties depending on source of the phytase gene and the production organism. The pH profiles of the enzymes showed that the fungal phytases had their pH optima ranging from 4.5 to 5.5. The bacterial E. coli phytase had also its pH optimum in the acidic range at pH 4.5 while the pH optimum for the Bacillus enzyme was identified at pH 7.0. Temperature optima were at 50 and 60 degrees C for the fungal and bacterial phytases, respectively. The Bacillus phytase was more thermostable in aqueous solutions than all other enzymes. In pelleting experiments performed at 60, 70 and 80 degrees C in the conditioner, Aspergillus A, Peniophora (measurement at pH 5.5) and E. coli phytases were more heat stable compared to other enzymes (Bacillus enzyme was not included). At a temperature of 70 degrees C in the conditioner, these enzymes maintained a residual activity of approximately 70% after pelleting compared to approximately 30% determined for the other enzymes. Incubation of enzyme preparations with porcine proteases revealed that only E. coli phytase was insensitive against pepsin and pancreatin. Incubation of the enzymes in digesta supernatants from various segments of the digestive tract of hens revealed that digesta from stomach inactivated the enzymes most efficiently except E. coli phytase which had a residual activity of 93% after 60 min incubation at 40 degrees C. It can be concluded that phytases of various microbial origins behave differently with respect to their in vitro properties which could be of importance for future developments of phytase preparations. Especially bacterial phytases contain properties like high temperature stability (Bacillus phytase) and high proteolytic stability (E. coli phytase) which make them favourable for future applications as feed additives.

6-Phytase↗
PubMed1991

Effectiveness of zinc bacitracin on production traits and energy metabolism of heat-stressed hens compared with hens kept under moderate temperature.

Two experiments with a total of 100 White Leghorn hens (26 to 59 wk of age) and 120 Rhode Island Red chickens (4 to 12 wk of age) were conducted to study the effect of 100 mg zinc bacitracin (ZBA)/kg of feed on hens and chickens acclimatized to 20 or 34 C environments. Layers were provided ad libitum access to a diet containing 11.12 MJ ME/kg (1 MJ = .239 Mcal) and 174 g CP/kg supplemented with 0 and 100 mg ZBA/kg. Body weight gain, egg number, total egg mass, and feed efficiency of ZBA-treated hens kept at a moderate temperature (20 C) were not significantly improved by 3.5, 2.6, 3.3, and 3.1%, respectively. However ZBA supplementation induced a more pronounced increase in performance in heat-stressed hens. The respective traits were significantly improved by 66.3, 15.4, 16.9, and 5.9%. Additionally, treated hens maintained at 34 C consumed significantly more feed than untreated hens. Eggshell breaking strength of treated hens held under normal conditions was not significantly improved. Feeding ZBA to heat-stressed hens led to a statistically higher breaking strength. Supplementation with ZBA for hens acclimatized to 20 and 34 C reduced fasting heat production by 4.1 and 7.6%, respectively. However, in the 20 C environment the differences were significant at only one of seven ages. The upper critical temperature (UCT) of ZBA-treated hens increased significantly at both temperatures from 34 to 42 wk of age relative to the control group. No significant effects of ZBA on UCT were observed at 24 to 32 wk and 40 to 52 wk of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Concentration-dependent effects of tolbutamide, meglitinide, glipizide, glibenclamide and diazoxide on ATP-regulated K+ currents in pancreatic B-cells.

The influence of the hypoglycemic drugs tolbutamide, meglitinide, glipizide and glibenclamide on ATP-dependent K+ currents of mouse pancreatic B-cells was studied using the whole-cell configuration of the patch-clamp technique. In the absence of albumin, tolbutamide blocked the currents half maximally at 4.1 mumol/l. In the presence of 2 mg/ml albumin half maximal inhibition of the currents was observed at 2.1 mumol/l meglitinide, 6.4 nmol/l glipizide and 4.0 nmol/l glibenclamide. The hyperglycemic sulfonamide diazoxide opened ATP-dependent K+ channels. Half maximally effective concentrations of diazoxide were 20 mumol/l with 0.3 mmol/l ATP and 102 mumol/l with 1 mmol/l ATP in the recording pipette. Thus, the action of diazoxide was dependent on the presence of ATP in the recording pipette. The free concentrations of the drugs which influenced ATP-dependent K+ currents were comparable with the free plasma concentrations in humans and the free concentrations which affected insulin secretion in vitro. The results support the view that the target for the actions of sulfonylureas and of diazoxide is the ATP-dependent K+ channel of the pancreatic B-cell or a structure closely related to this channel.

Adenosine Triphosphate↗
PubMed1981

[The development of weaned piglets experimentally infected with Isospora suis as a model for the effect of lasalocid and halofuginone on coccidia (author's transl)].

Piglets which were early-weaned at the age of 21.7 days and experimentally monoinfected with oocysts of Isospora suis showed distinct reductions in zootechnical criteria during an experimental period of 4 weeks. The daily liveweight gains in the infected piglets (group B) was 19.7% lower than in the control group A, which was free of Coccidia. Comparative photographs with the REM showed serious lesions in the small intestine of infected piglets, which are thought to be mainly responsible for the reduced productivity. The application of 150 mg Lasalocid per kg of total feed to infected piglets caused the rate of weight gain to attain the same values as the noninfected controls (group A). Piglets receiving Lasalocid treatment passed oocysts with the faeces which were infectious. On the other hand, infected piglets which were treated with 6 mg Halofuginone per kg of total feed did not contain any oocysts in the faeces. Despite having a higher liveweight at the beginning of the experiment, this group only gained as much liveweight as the infected piglets (group B). This depression in liveweight gains could be explained by the significantly reduced uptake of feed, which was 21.1% lower than in the controls (group A). 6 weeks after the first infection, a re-infection resulted in the appearance of oocysts in the faeces of the piglets which had been treated with Halofuginone. On the other hand, the animals treated with Lasalocid had developed an efficient immunity to Isospora suis.

Animals↗
PubMed1980

[Tissue reactions to bioactive bone cement].

In the field of bone surgery, bone cement has gained a considerable importance for the fixation of osteosynthesis material. This paper deals with the investigation of a new bone cement which is mixed with bioactive glass ceramic. In comparison to the conventional bone cement, all data pertaining to the material are improved, and histological examinations reveal an osseous connection to the superficially located glass ceramic particles.

Animals↗