Author J. Kowalczyk
ORIGINAL PAPER
Incorporation of endogenous urea nitrogen into amino acids of milk in goats fed diets with various protein levels
J. Anim. Feed Sci. 2014;23(3):212–216
ORIGINAL PAPER
Incorporation of endogenous urea nitrogen into the amino acids of bacterial protein in the rumen of goats fed diets with various protein levels
J. Anim. Feed Sci. 2013;22(4):311–315
ORIGINAL PAPER
Dietary lycopenes, selenium compounds and fish oil affect the profile of fatty acids and oxidative stress in chicken breast muscle
J. Anim. Feed Sci. 2012;21(4):705–724
ORIGINAL PAPER
Efficiency of endogenous urea 15N nitrogen incorporation into bacterial and milk protein of goats fed diets with three different protein levels
J. Anim. Feed Sci. 2012;21(4):599–612
ORIGINAL PAPER
Selenite and selenate affected the fatty acid profile in in vitro incubated ovine ruminal fluid containing linoleic acid
J. Anim. Feed Sci. 2012;21(3):477–492
ORIGINAL PAPER
Dietary linseed oil and selenate affect the concentration of fatty acids and selenium in the spleen, pancreas, and kidneys of lambs
J. Anim. Feed Sci. 2012;21(2):285–301
ORIGINAL PAPER
The effectiveness of rapeseed cake and glycerine in feeding dairy cows
J. Anim. Feed Sci. 2012;21(1):49–64
ORIGINAL PAPER
Dietary conjugated linoleic acid isomers and selenite or selenized yeast affect fatty acid concentration in the kidneys of rats
J. Anim. Feed Sci. 2011;20(3):432–448
ORIGINAL PAPER
Selenite, selenized yeast, or conjugated linoleic acid isomers supplemented to the diet influence the fatty acid profile in the spleen and blood plasma of rats
J. Anim. Feed Sci. 2010;19(4):613–627
ORIGINAL PAPER
The effect of conjugated linoleic acid isomers, selenite and selenized yeast supplemented to the diet on the fatty acid profile in the pancreas of rats
J. Anim. Feed Sci. 2010;19(3):495–508
ORIGINAL PAPER
Effect of feeding ensiled maize grain on rumen development and calf rearing performance
J. Anim. Feed Sci. 2010;19(2):195–210
ORIGINAL PAPER
Effect of a protein level in the diet on fatty acid profile in goat milk
J. Anim. Feed Sci. 2010;19(2):211–217
ORIGINAL PAPER
The dietary level of selenite and selenized yeast influences the concentrations of selected fatty acids in the abdominal fat and brain of rats
J. Anim. Feed Sci. 2010;19(1):113–129
ORIGINAL PAPER
Dietary selenite and conjugated linoleic acid isomers influence fatty acid concentrations in the liver and femoral muscles of rats
J. Anim. Feed Sci. 2009;18(3):564–581
ORIGINAL PAPER
Dietary selenized yeast and CLA isomer mixture affect fatty- and amino acid concentrations in the femoral muscles and liver of rats
J. Anim. Feed Sci. 2009;18(2):348–361
ORIGINAL PAPER
Protected methionine as a methyl-group donor for dairy cows fed diets with different starch sources in the transition period
J. Anim. Feed Sci. 2009;18(1):28–41
ORIGINAL PAPER
Effect of pre- and post-calving concentrate allocation and of starch source on feed intake, blood metabolite profiles and performance of transition cows
J. Anim. Feed Sci. 2008;17(4):473–490
ORIGINAL PAPER
Influence of selenate and linseed oil on fatty-acid and amino-acid profiles in the liver, muscles, fat tissues and blood plasma of sheep
J. Anim. Feed Sci. 2008;17(3):328–343
ORIGINAL PAPER
Lactic acid can be easily and precisely determined by reversed-phase high performance liquid chromatography with pre-column derivatization
J. Anim. Feed Sci. 2008;17(2):268–279
ORIGINAL PAPER
Comparison of the influence of different chemical forms of selenium and the profiles of CLA isomers in the diet on the fatty acid and amino acid contents in the liver and femoral muscles of rats
J. Anim. Feed Sci. 2007;16(4):678–695
SHORT COMMUNICATION
Effects of dietary fat source on physical, chemical and sensorial quality of calves’ meat
J. Anim. Feed Sci. 2007;16(Suppl. 2):554–559
SHORT COMMUNICATION
Response of milk fatty acid profile to various protein levels in goat diets with similar fatty acid content
J. Anim. Feed Sci. 2007;16(Suppl. 2):548–553
ORIGINAL PAPER
Influence of dietary CLA isomers and selenium compounds on the fatty acid and amino acid profiles in blood plasma of rats
J. Anim. Feed Sci. 2007;16(2):257–273
ORIGINAL PAPER
The influence of dietary conjugated linoleic acid isomers and selenized yeast on the fatty acid profile of the spleen, pancreas and kidneys of rats
J. Anim. Feed Sci. 2007;16(1):121–139
ORIGINAL PAPER
The use of developed chromatographic techniques to determine vitamin E and conjugated linoleic acid isomers in milk of cows
J. Anim. Feed Sci. 2007;16(Suppl. 1):90–96
ORIGINAL PAPER
The effects of linseed and rape seed cultivars and fish oil on the fatty acid profile of cow milk fat
J. Anim. Feed Sci. 2007;16(Suppl. 1):70–74
SHORT COMMUNICATION
The effect of a high forage diet and different oil blends on rumen fermentation in vitro
J. Anim. Feed Sci. 2006;15(Suppl. 1):141–144
SHORT COMMUNICATION
The effect of a forage diet and different fat sources on rumen fermentation in vitro
J. Anim. Feed Sci. 2006;15(Suppl. 1):129–132
SHORT COMMUNICATION
The influence of selenium on the level of linoleic acid isomers in incubated ruminal fluid
J. Anim. Feed Sci. 2006;15(Suppl. 1):97–100
SHORT COMMUNICATION
The influence of dietary conjugated linoleic acid isomers on the essential amino acid profile in rats
J. Anim. Feed Sci. 2006;15(Suppl. 1):69–72
SHORT COMMUNICATION
The concentration of conjugated linoleic acid isomers and their metabolites in the abdominal fat of rats
J. Anim. Feed Sci. 2006;15(Suppl. 1):61–64
ORIGINAL PAPER
The influence of dietary conjugated linoleic acid isomers and Se on the fatty acid profile in rat blood plasma and selected tissues
J. Anim. Feed Sci. 2006;15(3):471–489
SHORT COMMUNICATION
The effect of different oils and diets on methane release in an artificial rumen (Rusitec)
J. Anim. Feed Sci. 2006;15(Suppl. 1):149–152
SHORT COMMUNICATION
The effect of different oils and diets on total gas production in an artificial rumen (Rusitec)
J. Anim. Feed Sci. 2006;15(Suppl. 1):145–148
SHORT COMMUNICATION
The effect of a high concentrate diet and different fat sources on rumen fermentation in vitro
J. Anim. Feed Sci. 2006;15(Suppl. 1):137–140
SHORT COMMUNICATION
The effect of a high forage diet and different fat sources on rumen fermentation in vitro
J. Anim. Feed Sci. 2006;15(Suppl. 1):133–136
ORIGINAL PAPER
Dynamics of microbial contamination of protein during ruminal in situ incubation of feedstuffs
J. Anim. Feed Sci. 2006;15(2):313–328
ORIGINAL PAPER
Influence of dietary conjugated linoleic acid isomers and selenium on growth, feed efficiency, and liver fatty acid profile in rats
J. Anim. Feed Sci. 2006;15(1):131–146
SHORT COMMUNICATION
Improving the analysis of fatty acids using a combination of gas chromatography and Ag+ liquid chromatography
J. Anim. Feed Sci. 2005;14(Suppl. 1):563–566
SHORT COMMUNICATION
Dietary conjugated linoleic acid isomers and selenium affect the fatty acid profile in rat liver
J. Anim. Feed Sci. 2005;14(Suppl. 1):533–536
SHORT COMMUNICATION
Effect of dietary CLA isomers on selenium, zinc, copper, chromium, magnesium and calcium levels in rat liver
J. Anim. Feed Sci. 2005;14(Suppl. 1):529–532
SHORT COMMUNICATION
Influence of dietary conjugated linoleic acid (CLA) on the fatty acid content and CLA profile of egg yolks in laying hens
J. Anim. Feed Sci. 2005;14(Suppl. 1):435–438
SHORT COMMUNICATION
The effect of fish oil in calf diets on the fatty-acid content of Musculus thoracis intramuscular fat
J. Anim. Feed Sci. 2005;14(Suppl. 1):319–322
SHORT COMMUNICATION
The stability of silage containing biological and chemical additives assessed using a Rusitec system
A. Potkański, A. Cieślak, M. Szumacher-Strabel, S. Wylegała, K. Raczkowska-Werwińska, A. Gubała, J. Kowalczyk
J. Anim. Feed Sci. 2005;14(Suppl. 1):307–310
SHORT COMMUNICATION
Excretion routes and distribution of selenium in sheep tissues after selenite loading
J. Anim. Feed Sci. 2005;14(Suppl. 1):303–306
SHORT COMMUNICATION
Concentrate-enriched diets for calving heifers in the periparturient period increase milk yield and improve blood metabolite profile
J. Anim. Feed Sci. 2005;14(Suppl. 1):259–262
SHORT COMMUNICATION
Short-term vasopressin analogue treatment does not influence the nitrogen balance in sheep
J. Anim. Feed Sci. 2005;14(Suppl. 1):251–254
SHORT COMMUNICATION
Methane production in in vitro studies as an effect of different additives to grass-clover silage
A. Cieślak, A. Potkański, J. Kowalczyk, M. Szumacher-Strabel, K. Czaczyk, A. Gubała, M. Janicki, E. Szymankiewicz
J. Anim. Feed Sci. 2005;14(Suppl. 1):235–238
ORIGINAL PAPER
The effect of linseed oil and selenium on the content of fatty acids and some elements in the liver and selected tissues of sheep
J. Anim. Feed Sci. 2004;13(Suppl. 2):105–108
SHORT COMMUNICATION
A highly efficient method for determination of allantoin in ruminal digesta, ovine urine and blood serum by HPLC
J. Anim. Feed Sci. 2004;13(Suppl. 2):67–70
SHORT COMMUNICATION
Blood parameters of lambs fed diets with vegetable oil supplements
J. Anim. Feed Sci. 2004;13(Suppl. 2):23–26
SHORT COMMUNICATION
Effect of adding fat to the diet for lambs on the fatty acid profile of intramuscular, perirenal and subcutaneous fat
J. Anim. Feed Sci. 2004;13(Suppl. 1):355–358
SHORT COMMUNICATION
Changes in fermentation processes as the effect of vegetable oil supplementation in in vitro studies
J. Anim. Feed Sci. 2004;13(Suppl. 1):215–218
SHORT COMMUNICATION
Digestion of starch and crude fibre in segments of the digestive tract of sheep fed different types and amounts of starch
J. Anim. Feed Sci. 2004;13(Suppl. 1):123–126
SHORT COMMUNICATION
Simultaneous determination of purine metabolites in ovine urine and blood plasma by high-performance liquid chromatography
J. Anim. Feed Sci. 2004;13(Suppl. 1):55–58
ORIGINAL PAPER
Liver and body mass gain, content of conjugated linoleic acid (CLA) isomers and other fatty acids in the liver of rats fed CLA isomers and selenium
M. Czauderna, J. Kowalczyk, K. M. Niedźwiedzka, I. Wąsowska, B. Pastuszewska, E. Bulska, A. Ruszczyńska
J. Anim. Feed Sci. 2004;13(2):353–369
ORIGINAL PAPER
Conjugated linoleic acid (CLA) content and fatty acids composition of muscle in rats fed isomers of CLA and selenium
J. Anim. Feed Sci. 2004;13(1):183–196
ORIGINAL PAPER
The effects of selenium and conjugated linoleic acid (CLA) isomers on fatty acid composition, CLA isomer content in tissues, and growth of rats
J. Anim. Feed Sci. 2003;12(4):865–881
ORIGINAL PAPER
The urinary excretion of purine derivatives in sheep is not influenced by long term treatment with vasopressin
J. Anim. Feed Sci. 2003;12(3):513–520
ORIGINAL PAPER
Efficiency of metabolizable and net energy in growing bulls fed diets with maize silage
J. Anim. Feed Sci. 2003;12(3):475–486
ORIGINAL PAPER
Development of a method for measuring lysine and methionine bioavailability in rumen-protected products for cattle
J. Anim. Feed Sci. 2003;12(3):465–474
ORIGINAL PAPER
Determination of conjugated linoleic acid isomers by liquid chromatography and photodiode array detection
J. Anim. Feed Sci. 2003;12(2):369–382
ORIGINAL PAPER
Fatty acid flow to the duodenum of sheep fed diets supplemented with different types of fat
M. Szumacher-Strabel, A. Potkański, J. Kowalczyk, A. Cieślak, M. Czauderna, G. Strzelecka, P. Jędroszkowiak
J. Anim. Feed Sci. 2003;12(2):239–248
ORIGINAL PAPER
A highly efficient method for determination of some amino acids and glutathione by liquid chromatography
J. Anim. Feed Sci. 2003;12(1):199–215
ORIGINAL PAPER
A note on the influence of fat supplementation of sheep rations on the level of purine derivatives in urine and bacterial synthesis in the rumen
J. Anim. Feed Sci. 2003;12(1):65–70
ORIGINAL PAPER
Studies on N-metabolism in different gastrointestinal sections of sheep using the digesta exchange technique. 4. Whole body protein metabolism
A. Sandek, K. Krawielitzki, J. Kowalczyk, M. Gabel, T. Żebrowska, F. Kreienbring, H. Hagemeister, J. Voigt
J. Anim. Feed Sci. 2002;11(4):589–599
ORIGINAL PAPER
The influence of supplemental fat on rumen volatile fatty acid profle, ammonia and pH levels in sheep fed a standard diet
M. Szumacher-Strabel, A. Potkański, J. Kowalczyk, A. Cieślak, M. Czauderna, A. Gubała, P. Jędroszkowiak
J. Anim. Feed Sci. 2002;11(4):577–587
ORIGINAL PAPER
A highly efficient method for derivatization of fatty acids for high performance liquid chromatography
J. Anim. Feed Sci. 2002;11(3):517–526
ORIGINAL PAPER
Milk yield, composition and cholesterol level in dairy cows fed rations supplemented with zinc and fatty acid calcium salts
J. Anim. Feed Sci. 2002;11(3):411–424
ORIGINAL PAPER
A HPLC method with UV detection for analysing of 2,6-diaminopimelic acid in rumen bacteria and intestinal digesta
J. Anim. Feed Sci. 2002;11(2):331–346
ORIGINAL PAPER
Studies on N-metabolism in different gastrointestinal sections of sheep using the digesta exchange technique. 3. N secretion and reabsorption
A. Sandek, K. Krawielitzki, J. Kowalczyk, F. Kreienbring, M. Gabel, U. Schönhusen, T. Żebrowska, H. Hagemeister, J. Voigt
J. Anim. Feed Sci. 2002;11(2):277–288
ORIGINAL PAPER
Determination of free- and protein primary amino acids in biological materials by high-performance liquid chromatography and photodiode array detection
J. Anim. Feed Sci. 2002;11(1):143–167
ORIGINAL PAPER
A note on the effect of different amounts and types of fat on the fatty acid composition of duodenal digesta in sheep
J. Anim. Feed Sci. 2001;10(4):627–632
ORIGINAL PAPER
The influence of dietary protein and fibre on bile-pancreatic secretion in sheep
J. Anim. Feed Sci. 2001;10(4):619–626
ORIGINAL PAPER
Studies on N-metabolism in different gastrointestinal sections of sheep using the digesta exchange technique. 2. Passage of endogenous nitrogen
A. Sandek, K. Krawielitzki, J. Kowalczyk, F. Kreienbring, U. Schönhusen, M. Gabel, T. Żebrowska, H. Hangemeister, J. Voigt
J. Anim. Feed Sci. 2001;10(4):605–618
ORIGINAL PAPER
Milk yield and composition in cows fed rations with different energy and protein sources
J. Anim. Feed Sci. 2001;10(4):569–588
ORIGINAL PAPER
Studies on N-metabolism in different gastrointestinal sections of sheep using the digesta exchange technique. 1. Model and experimental conditions
J. Anim. Feed Sci. 2001;10(3):421–434
ORIGINAL PAPER
Effect of milk replacer feeding frequency and level on concentrate intake and rearing performance of calves
J. Anim. Feed Sci. 2001;10(3):413–420
SHORT COMMUNICATION
Quantification of conjugated linoleic acid and other essential fatty acids in ovine meat, milk, fat, and intestinal digesta
J. Anim. Feed Sci. 2001;10(Suppl. 2):385–392
SHORT COMMUNICATION
An HPLC method for determining desirable or undesirable conjugated linoleic acid
J. Anim. Feed Sci. 2001;10(Suppl. 2):377–383
SHORT COMMUNICATION
An improved method for derivatization of fatty acids for liquid chromatography
J. Anim. Feed Sci. 2001;10(Suppl. 2):369–375
SHORT COMMUNICATION
Effect of extrusion-cooking temperature on the nutritive value of lupin seeds in fattening lambs
J. Anim. Feed Sci. 2001;10(Suppl. 2):357–362
SHORT COMMUNICATION
The effects of different amounts and types of fat on the extent of C18 unsaturated fatty acid hydrogenation in the rumen of sheep
J. Anim. Feed Sci. 2001;10(Suppl. 2):123–128
SHORT COMMUNICATION
The effects of different amounts and types of fat on milk fatty acid composition in sheep
J. Anim. Feed Sci. 2001;10(Suppl. 2):115–121
SHORT COMMUNICATION
The effects of different amounts and types of fat on meat fatty acid composition in sheep
J. Anim. Feed Sci. 2001;10(Suppl. 2):109–113
SHORT COMMUNICATION
The effects of different amounts and types of fat on the level of conjugated linoleic acid in the meat and milk of sheep
J. Anim. Feed Sci. 2001;10(Suppl. 2):103–108
SHORT COMMUNICATION
The effects of different amounts and types of fat on rumen microbial protein synthesis in sheep
J. Anim. Feed Sci. 2001;10(Suppl. 2):97–101
SHORT COMMUNICATION
The effects of different amounts and types of fat on metabolites in the rumen of sheep
J. Anim. Feed Sci. 2001;10(Suppl. 2):91–96
SHORT COMMUNICATION
Effect of milk thistle (Sylibum marianum L.) endosperm in the diet for cows on milk yield and fatty acid profiles
J. Anim. Feed Sci. 2001;10(Suppl. 2):83–89
SHORT COMMUNICATION
The influence of dietary starch level and type on the activity of pancreatic digestive enzymes in sheep
J. Anim. Feed Sci. 2001;10(Suppl. 2):57–63
ORIGINAL PAPER
A note on the effect of energy sources on duodenal flow of fatty acids and bacterial nitrogen in sheep
J. Anim. Feed Sci. 2001;10(2):293–300
ORIGINAL PAPER
Fattening bulls on maize silage and concentrate supplemented with vegetable oils
J. Anim. Feed Sci. 2001;10(2):259–271
ORIGINAL PAPER
Performance and meat quality of fattening bulls fed complete feed with rapeseed oil cake or linseed
J. Anim. Feed Sci. 2000;9(2):283–296
ORIGINAL PAPER
Effect of diets with hydrolysed feather keratin meal on milk yield and composition in dairy cow and calf performance
J. Anim. Feed Sci. 1999;8(4):497–512
ORIGINAL PAPER
Nutritive value of feather keratin meals for ruminants
J. Anim. Feed Sci. 1999;8(3):387–393
ORIGINAL PAPER
Determination of 2,6-diaminopimelic acid in bacteria, ruminal and duodenal digesta using HPLC with fluorescence or UV detection
J. Anim. Feed Sci. 1999;8(2):273–288
ORIGINAL PAPER
Nitrogen secretion and absorption in different segments of the digestive tract estimated by digesta exchange between 15N-labelled and unlabelled sheep
K. Krawielitzki, A. Sandek, J. Kowalczyk, F. Kreienbring, T. Żebrowska, B. Skiba, J. Voigt, M. Gabel, H. Hagemeister
J. Anim. Feed Sci. 1999;8(2):129–143
ORIGINAL PAPER
Milk yield and composition in dairy cows fed a diet with evening primrose (Oenothera paradoxa) full fat seeds or oil cake
J. Anim. Feed Sci. 1999;8(1):89–94
ORIGINAL PAPER
Determination of free amino acids in blood plasma by high-performance liquid chromatography with fluorescence detection
J. Anim. Feed Sci. 1998;7(4):453–463
ORIGINAL PAPER
A note on rearing calves on diets supplemented with evening primrose (Oenothera paradoxa) oil cake
J. Anim. Feed Sci. 1998;7(4):377–383
ORIGINAL PAPER
Evening primrose (Oenothera paradoxa) oil cake or ground rape seed supplement to diets for dairy cow
J. Anim. Feed Sci. 1998;7(4):365–375
SHORT COMMUNICATION
Effect of various probiotics on calf performance
J. Anim. Feed Sci. 1998;7(Suppl. 1):241–244
ORIGINAL PAPER
Nitrogen conversion and apparent intestinal amino acid absorption in young bulls fed isonitrogenous diets with different nitrogen sources
J. Anim. Feed Sci. 1998;7(3):273–282
ORIGINAL PAPER
Performance and body fat composition of fattening bulls fed diets with evening primrose (Oenothera paradoxa) oil cake
J. Anim. Feed Sci. 1998;7(3):261–271
ORIGINAL PAPER
Nutritive value of evening primrose (Oenothera paradoxa) cake for ruminants
J. Anim. Feed Sci. 1998;7(2):187–195
ORIGINAL PAPER
Simultaneous determination of purine derivatives in urine by high-performance liquid chromatography
J. Anim. Feed Sci. 1996;5(4):433–439
ORIGINAL PAPER
A device for quantitative urine collection from male sheep in balance trials
J. Anim. Feed Sci. 1996;5(3):297–301
ORIGINAL PAPER
Nitrogen compounds and volatile fatty acids absorption from the caecum and colon of sheep
J. Anim. Feed Sci. 1996;5(1):25–34
ORIGINAL PAPER
Yeast cells as a feed supplement for cattle 3. New yeast preparations for cows in the first period of lactation
J. Anim. Feed Sci. 1996;5(1):1–9
ORIGINAL PAPER
Determination of allantoin in blood by high-performance liquid chromatography with pre-column derivatization
J. Anim. Feed Sci. 1995;4(4):351–358
ORIGINAL PAPER
Secretion of nitrogen compounds into the isolated caecum and colon of sheep
J. Anim. Feed Sci. 1995;4(4):321–331
ORIGINAL PAPER
Yeast cells as a feed supplement for cattle. 2. Effect of liquid yeast cultures on digestive processes in the rumen of bulls
J. A. Strzetelski, J. Maciejewicz-Ryś, R. Ryś, J. Kowalczyk, B. Niwińska, T. Stasiniewicz, K. Maciaszek
J. Anim. Feed Sci. 1995;4(4):287–297
ORIGINAL PAPER
Intestinal nitrogen flow, total nitrogen and 15N balance in pigs labelled intravenously with 15N-leucine and fed a meat meal diet
J. Anim. Feed Sci. 1995;4(3):207–215
ORIGINAL PAPER
Yeast cells as a feed supplement for cattle 1. Liquid viable yeast cultures for calves
J. Anim. Feed Sci. 1995;4(3):171–181
ORIGINAL PAPER
Treatment of barley straw with ammonia or urea solutions and digestibility of its structural carbohydrate fractions in sheep
J. Anim. Feed Sci. 1994;3(2):129–139
ORIGINAL PAPER
The rate of free amino acid disappearance from the rumen content
J. Anim. Feed Sci. 1994;3(1):11–22
ORIGINAL PAPER
Performance and wool growth in lambs fed rations containing formaldehyde treated protein
J. Anim. Feed Sci. 1993;2(1-2):35–42
ORIGINAL PAPER
Studies on absorption and secretion of 15N endogenous nitrogen along the digestive tract of pigs
J. Anim. Feed Sci. 1992;1(2):151–163
ORIGINAL PAPER
The use of rape seeds in a complete feed in intensive fattening of young bulls
J. Anim. Feed Sci. 1992;1(2):107–116
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