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Biomedical subjects

J Zentek

Publications and source records attributed to J Zentek.

At least 19 recordsLinked to original sources
PubMed2002

[Efficacy of probiotic feed additives: guidelines for the evaluation of the efficiency of microorganisms in dogs, cats, and horses].

Probiotic microorganisms are frequently in use as feed additives for farm and pet animals. For admission for the common market products have to be tested according to the feed additive directive 70/524/EC. The dossier for admission has to comprise data of efficiency as laid down in the directive 87/153/EC. During the last years it became obvious after the evaluation of several dossiers, that no definitive criteria for the assessment of efficacy were available for dogs, cats and horses (84/153/EC). Aspects like the promotion of animal production are not relevant in this context. Therefore, the European commission launched the directive for the evaluation of efficacy of microorganisms for dogs, cats and horses, that supports the evaluation of microbial feed additives and which is described in this paper.

Animal Feed↗
PubMed2002

[Animal-derived feedstuffs as possible vectors for bovine encephalopathy (BSE) in Germany. Part 2: Assessment of vector risk for compounded feed].

Specific conditions and practices of cattle feeding in Germany have to be taken into account for assessing the risk of feed born transmission of bovine spongiform encephalopathy, especially regarding the situation before the year 2000 when specific directives were introduced for feed production. The present retrospective epidemiological study includes data on feed production and the estimated amount of animal derived feedstuffs for the production of compounded feed for cattle. Risk assessment was performed based on the 'reproduction rate' (R0), that is defined as the estimated number of infections resulting from the processing of brain and spinal cord of BSE affected cattle that is recycled to bovines via feed. Under the conditions as given in Germany until the year 2000 the reproduction rate of BSE via the inclusion of animal derived feedstuffs in compounded feed production for cattle was estimated to be 1.1. Thus, it can be expected that BSE could be reproduced in the system, but with comparatively low efficiency. The expected incidence of BSE should be considerably lower compared to the situation during the 90th in the UK, due to the markedly lower recycling rate of animal protein in cattle feeding. Animal fat could have been a significant factor for BSE transmission due to contamination by proteinaceous brain and spinal cord material during the production process. The relative significance of fat containing feedstuffs for BSE transmission could have been higher in Germany compared to the situation in the UK where meat and bone meal was produced under different conditions and frequently used in higher proportions as an ingredient for compounded feed for ruminants.

Animal Feed↗
PubMed2001

[Animal-derived feeds as possible vectors for bovine spongiform encephalopathy (BSE) in Germany. 1. Comparative risk assessment for a single animal food of animal origin].

The occurrence of BSE cases in Germany after the ban of meat and bone meal for ruminant feed in 1994 requires a detailed investigation of animal derived feedstuffs regarding their specific risks as vectors for the disease. Accepting the theory that BSE is a prion transmitted disease, the theoretical infectious potential was calculated for animal derived feedstuffs. This calculation was based on the assumption, that risk material (brain, spinal cord) of one clinically diseased cattle was rendered in the process as established in Germany (133 degrees C, 3 bar, 20 min) or, alternatively, that one diseased animal was slaughtered resulting in normal processing of the by-products for human food production. From this risk assessment it became obvious that meat and bone meal was one, but probably not the most important source for the spreading of BSE. Taking into account the high sensitivity of calves it can be speculated that certain products, e.g. from bone processing (bone meal) and fat melting (mixed animal fats), commonly used for the formulation of milk replacers, might have been more important as pathways. As it can't be excluded retrospectively that infected meat and bone meal was imported from the UK, this non-calculable influence may have been related to the significance of the other products. The calculation model underlines that efficient removal of specified risk material (brain, spinal cord) and adequate processing (133 degrees C, 3 bar, 20 min) or alternatively other equivalent treatments of fats are prerequisites for minimising the risk of feed borne transmission of BSE by animal derived feedstuffs. The epidemiological consequences are part of a subsequent paper.

Animal Feed↗
PubMed2000

[Animal nutrition for veterinarians--recent cases: odor variations in eggs from brown hens and also possibly in "noncritical" feed composition].

Fishy or unpleasant egg taint occurred in a high frequency (10%) in a herd of brown layers. The hens were fed a commercial standard diet, that did not contain the known critical ingredients as fish meal or rape seed and had an average choline concentration. Sensory tests of the drinking water did not reveal any abnormalities. In a subsequent feeding trial an oral antibiotic treatment with neomycin alone had no positive effects while neomycin and tetracycline reduced egg taint significantly until it became almost normal. Microbial activities in the GI tract were therefore obviously responsible for the egg taint.

Animal Feed↗
PubMed1999

Digestibility and compatibility of mixed diets and faecal consistency in different breeds of dog.

The digestive capacity of dogs varying in body size was tested. Digestive experiments were conducted with 10 different canine breeds (n = 66) with body weights ranging from 4.2 to 52.5 kg with 4-9 individuals. The animals were fed a canned or a dry commercial diet with a constant dry matter intake of 13 g/kg BW/day, except in Irish wolfhounds, which ingested only 10 g dry matter with the canned diet. Faecal dry matter was around 14% (absolutely) higher for the dry diet compared to the canned food, with a tendency in the larger breeds towards higher faecal water contents, less favourable faecal quality and increased numbers of defaecations. The Irish wolfhounds, the largest breed tested, had faeces with considerably lower water contents compared to Labrador retrievers, indicating that body weight is not the only factor to be considered. There were only small differences in the apparent digestibility of crude nutrients amongst the breeds. Sodium and potassium absorption was higher when the dry diet was fed compared to the canned food. In conclusion, breed and individual factors have to be taken into account when performing tests with dog food. Test panels for evaluating commercial diets should include breeds of larger body size and higher sensitivity to dietary disorders.

Animal Feed↗
PubMed1999

[Animal nutrition in veterinary medicine--actual cases: copper intoxication in piglets].

A case is described where piglets reacted with severely reduced feed intake, watery and dark faeces, poor growth and rough hair coat after delivery of a new charge of a commercial pelleted diet. Body temperature was normal, the behaviour appeared depressed. The diet contained 860 mg copper/kg, which was highly above the labelled concentration (160 mg/kg) and the concentration allowed by feed legislation (175 mg/kg for pigs up to 16 weeks of age). After changing to a new mixed feed the general condition of the piglets improved and faecal consistency and colour normalised within a few days.

Animal Feed↗
PubMed1999

[Animal nutrition in veterinary medicine--an actual case: high incidence of constipation in calf rearing].

A high frequency of constipation was observed in calves with an average body weight of 150 kg. Eleven out of 200 animals died, at necropsy intestinal obstruction was identified due to agglomeration of stone like particles, identified as shell fragments of palm kernels. The calves were fed 3 kg maize silage, 1.5 kg of a commercial mixed feed, 0.5 kg soya meal, and 50 g of a mineral supplement. Hay was offered ad libitum, all animals had free access to drinking water. The composition of the mixed diet was estimated by microscopy and was completely different from the label as provided by the manufacturer. A palm kernel product with high amounts of stone shells was identified in a concentration of 25% of the mixed feed, confirming the findings in the necropsied calves. The pathogenesis of the obstruction seemed to be influenced by a concurrent infectious disease, which might have had negative effects on the gastro-intestinal motility.

Animal Feed↗
PubMed1999

[Accident report: animal nutrition in veterinary medicine--actual cases: houndstongue (Cynoglossum officinale) in pasture--a health hazard for horses].

Meteorism and colics were observed in horses after grazing on young pasture. The botanical analysis of a sample as taken by the owner revealed a great diversity of grasses, herbs and legumes. Houndstongue (Cynoglossum officinale) in its rosette stage was identified in amounts of 1% of the total sample, although this cannot be regarded as representative for the composition of the green fodder. This plant has been reported to be highly toxic for horses and other species, mainly during the early growth stadium due to its contents of pyrrolizidin alkaloids with a strong hepatotoxic activity. In the present case it remained unclear, whether the horses actually ingested this poisonous plant in relevant amounts. In general it has to be emphasised, that a contamination especially of hay or silage bears a severe risk for horses. The contamination of green fodder with houndstongue can be a serious problem for the feeding practice in certain regions (dry grassland, loess or shell lime soil, extensive management).

Animal Feed↗
PubMed1998

Nutrition and osteochondrosis.

Developmental orthopedic disease is a group of musculoskeletal disorders that occur in growing animals (most commonly fast growing, large breed dogs). Osteochondritis dissecans and canine hip dysplasia are the overwhelming majority of the diagnoses in those musculoskeletal problems with a possible nutritional-related etiology. Nutritional management alone will not completely control osteochondrosis or any of the developmental bone diseases. However, osteochondrosis and other developmental orthopedic diseases can be influenced during growth by feeding technique and nutrient profile. Dietary deficiencies are of minimal concern in this age of commercial foods specifically prepared for young, growing dogs. The potential for harm is in overnutrition from excess consumption and over supplementation.

Animal Nutritional Physiological Phenomena↗
PubMed1997

[Animal nutrition in veterinary medicine: actual situations: decreased feed intake in swine].

Two cases of vitamin D3 intoxication in piglets are described. The dietary concentrations of vitamin D3 were 265 and 435 thousand IE/kg. Decreased feed intake, growth depression and polyuria or polydypsia were observed. In some animals hypercalcemia and symptoms of impaired renal function were found. Pathological findings included calcinosis of several tissues and degenerative damage.

Animal Feed↗
PubMed1997

[Case report: tympany and diarrhea in calves].

Diarrhoea and meteorism was observed in calves, that were fed on hay, linseed and milk replacer. Different factors were found in the feedstuffs, which could have caused these symptoms. The feeding value of the hay was not high enough due to intense lignification, while the milk replacer showed a slightly impaired hygienic quality. The linseed contained cyanogenic glycosides in higher concentrations (226 mg HCN/kg).

Animal Feed↗
PubMed1997

[Case report: decreased laying performance as a contributing problem].

In 2 laying hen flocks (housed in aviary systems) depressed performance, increased mortality and cannibalism were observed. Specific infectious diseases were excluded. The hygienic quality of the diet, however, based on self produced feed ingredients, was impaired. High concentrations of bacteria, moulds, and yeasts were found in the complete diet and also in the ingredients. These problems were eliminated by providing the birds with good quality feed ingredients. In a diagnostic feeding trial with a change in housing conditions hens showed a good performance. The poor feed quality, as demonstrated in this report, is regarded to be one of several factors, which have contributed to the problems observed in these flocks. Other negative environmental factors such as housing have to be eliminated.

Animal Feed↗
PubMed1997

[Feeding of reptiles: practice and problems].

Reptiles show a high degree of physiological adaptation to their habitates. The digestive tract is characteristic in herbi- or folivorous, omni-, ovi- and carnivorous species, mainly differing in the length and volume of small and large intestine. The specialization requires adequate feeding methods for captured reptiles, not only with regards to the composition of the diet, but also to the feeding techniques. The quantitative knowledge of energy and nutrient requirements is still incomplete and feeding experiments are urgently required. Energy demand for maintenance is considerably lower than in warm blooded species (around 50-60 kJ ME/kg BW0.75/d). Nutritional disorders are found mainly in herbivorous species, especially if unbalanced rations with only one or two feedstuffs are offered. Among nutrient deficiencies, concerning vitamins and minerals, overdosage of some nutrients is encountered occasionally, which may be detrimental especially in case of vitamin A and D.

Acclimatization↗
PubMed1996

[Performance of broiler chickens and quality of litter in various housing conditions (stocking density)].

In the present study the influence of a reduced stocking density on body weight, feed and water intake as well as the dry matter and nitrogen-centent (N) of bedding was examined in 3 fattening periods (2 x conventional closed stable, each 36 days, 1 x Louisiana stable, 40 days). In the controlls (stocking density 38 kg/m2) the broilers achieved a mean slaughter weight of 1497, 1411 and 1681 g, under experimental conditions (stocking density on average 33 kg/m2) the compareable figures were 1555, 1431 and 1793 g. Feed conversion ratios were better and the mortality during the fattening periods were lower in groups with reduced stocking density than in the controlls. There was no remarkable improvement of litter quality during the fattening periods in dependence on reduced stocking density. The dry matter content of litter decreased to 60%. At end of fattening the bedding contained 6-9g NH3-N, 7-17 g urea-N and 0,4-4 g uric acid-N/kg wet weight. The lowest uric acid values were found in the bedding samples from Louisiana stables. Effects of a reduced stocking density became obvious only in conventional closed stables by lowered NH3-N-concentrations. The stocking density had no influence on the distribution of the different fractions of NPN with regard to total N.

Animal Husbandry↗
PubMed1995

Normal handling of diets--are all dogs created equal?

Observations on food tolerance in dogs have shown that differences occur between breeds--especially in the giant breeds which can have an increased frequency of soft stools. This may be explained, at least in part, by differences in the dogs' ability to utilise a diet. To investigate this phenomenon, four digestive trials were conducted using two canned and two dried commercial diets. The ability to digest most nutrients was lower in the great danes in three out of the four trials. The great danes also had a significantly higher faecal loss of water, sodium and potassium. The underlying causes should be associated with the relationship between body-weight and the gastrointestinal tract or with differences in transit time of the ingesta, particularly through the large intestine.

Animal Feed↗