Stanovenie bielkovín v rôznych krmivách metódou in sacco v porovnaní s metódou CNCPS

The aim of this study was to determine the correlations between the output parameters of the in sacco method and the CNCPS method (Cornell Net Carbohydrate and Protein System). Both methods were tested on 106 samples from the feeds classified into following categories: extracted meal and cakes, cereals, legumes, maize and alfalfa silage, other silages, DDGS (dried distiller’s grains with solubles), oilseeds and various hays. The effective degradability of crude protein (EDg CP) by the in sacco method varied depending on the type of feed from 44.97% (hays) to 82.59% (alfalfa silage). The lowest degradation parameter of rapidly degraded fraction (a=24.3%) and the highest potentially degraded fraction (b=70.52%) were found in oilseeds. Five nitrogen fractions (A, B1, B2, B3, C) were determined according to the CNCPS method. Fraction A (NPN – non-protein nitrogen) was different in examined feed with the highest in silages (44.95% of the total CP). Fraction B2 represented in tested feeds the highest part of the total CP, (except for silages, legumes, and oilseeds). Fraction B3 ranged from 1.96% (legumes) to 19.25% (hays) of the total CP. The correlation between EDg CP and soluble fractions was low (r=0.5464) in concentrate feeds, the correlation between EDg and soluble fractions was (r=0.6323) also low in forages.Cieľom tohto príspevku bolo stanoviť korelačné vzťahy medzi výstupnými parametrami metódy in sacco a metódy CNCPS (Cornell Net Carbohydrate and Protein System). Metódy in sacco a CNCPS boli testované na rôznych krmivách (n=106). Krmivá boli rozdelené do jednotlivých kategórií: extrahované šroty a výlisky, obilniny, strukoviny, kukuričná a lucernová siláž, ostatné siláže, DDGS (sušené liehovarnícke výpalky s rozpustnými zložkami), olejniny a rôzne seno. Efektívna degradovateľnosť dusíkatých látok (EDg N-látok) metódou in sacco sa pohybovala v závislosti od typu krmiva od 44,97 % (seno) do 82,59 % (lucernová siláž). Najnižší parameter rozpustnej a degradovateľnej frakcie (a) a najvyššia nerozpustná a degradovateľná frakcia (b) bola zistená v olejnatých semenách (70,52 %). Päť dusíkových frakcií (A, B1, B2, B3, C) bolo stanovených podľa metódy CNCPS. Frakcia A (NPN - nebielkovinový dusík) bola v skúmanom krmive odlišná, najvyššia v silážach (44,94 % z celkových dusíkatých látok). Frakcia B2 predstavovala v testovaných krmivách najvyšší podiel z celkových dusíkatých látok, okrem siláží. Frakcia B3 sa pohybovala od 1,96 % (strukoviny) do 19,25 % (seno) z celkových dusíkatých látok. Korelácia pre jadrové krmivá medzi EDg N-látok a rozpustnými frakciami bola slabá (r=0,5464). Podobne to bolo aj u objemových krmív, kde korelácia medzi EDg N-látok a rozpustnými frakciami bola r=0,6323

The effect of different dietary zinc sources on mineral deposition and antioxidant indices in rabbit tissues

[EN] The purpose of this study was to compare the effect of dietary zinc from inorganic and organic sources on the concentration of Zn, Cu, Mn and Fe in plasma, tissues and faeces of rabbits. Simultaneously, the activities of total superoxide dismutase (SOD), specific Cu/Zn SOD, glutathione peroxidase (GPx), lipid peroxidation and total antioxidant capacity (TAC) in liver and kidney were also determined. Ninety-six 49-day-old broiler rabbits were allocated to 4 dietary treatments, each replicated 6 times with 4 animals per replicate. For the subsequent 6 wk, the rabbits were fed an identical basal diet (BD) supplemented with an equivalent dose of Zn (100 mg/kg) from different sources. Group 1 (control) received the unsupplemented BD, while the BD for groups 2, 3 and 4 was supplemented with Zn from Zn sulphate, Zn chelate of glycine hydrate (Zn-Gly) and Zn chelate of protein hydrolysate (Zn-Pro), respectively. The intake of dietary Zn sulphate resulted in an increase in Zn plasma concentration (1.85 vs. 1.48 mg/L; P<0.05) compared to the control group. Feeding the diets enriched with Zn increased the deposition of Zn in the liver (P<0.05), irrespective of the Zn source. The addition of Zn-Pro resulted in significantly higher Cu uptake in liver (P<0.05) than in the control and Zn sulphate group (56.0 vs. 35.0 and 36.7 mg/kg dry matter (DM), respectively). Neither Mn nor Fe concentration in plasma and tissues were affected by dietary Zn supplementation, with the exception of Fe deposition in muscle, which was significantly decreased (P<0.05) in rabbits supplemented with inorganic Zn sulphate compared to control and Zn-Gly group (9.8 vs. 13.3 and 12.2 mg/kg DM, respectively). Intake of organic Zn-Gly significantly increased the activities of total SOD (43.9 vs. 35.9 U/mg protein; P<0.05) and Cu/Zn SOD (31.1 vs. 23.8 U/mg protein; P<0.01) as well as TAC (37.8 vs. 31.2 μmol/g protein; P<0.05) in the kidney when compared to that of the control group. The presented results did not indicate any differences between dietary Zn sources in Zn deposition and measured antioxidant indices in rabbit tissues. Higher dietary Zn intake did not cause any interactions with respect to Mn, Cu and Fe deposition in liver and kidney tissues, but did increase the faecal mineral concentrations. Dietary organic Zn-Gly improved the antioxidant status in rabbit kidney.This work was supported by the Slovak Research and Development Agency under contract nº. APVV-0667-12 and by the project ITMS 26220220204.Čobanová, K.; Chrastinová, Ľ.; Chrenková, M.; Polačiková, M.; Formelová, Z.; Ivanišinová, O.; Ryzner, M.... (2018). The effect of different dietary zinc sources on mineral deposition and antioxidant indices in rabbit tissues. World Rabbit Science. 26(3):241-248. https://doi.org/10.4995/wrs.2018.9206SWORD241248263Alscher D.M., Braun N., Biegger D., Stuelten C., Gawronski K., Mürdter T.E., Kuhlmann U., Fritz P. 2005. Induction of metallothionein in proximal tubular cells by zinc and its potential as an endogenous antioxidant. Kidney Blood Press Res., 28: 127-133. https://doi.org/10.1159/000084921Ao T., Pierce J.L., Power R., Pescatore A.J., Cantor A.H., Dawson K.A., Ford M.J. 2009. Effects of feeding different forms of zinc and copper on the performance and tissue mineral content of chicks. Poultry Sci., 88: 2171-2175. https://doi.org/10.3382/ps.2009-00117AOAC 2005. Official Methods of Analysis. 18th Edition. Association of Official Analytical Chemists, Gaithersburg, USA.Bao Y.M., Choct M., Iji P.A., Brueton K. 2007. Effect of organically complexed copper, iron, manganese and zinc on broiler performance, mineral excretion and accumulation in tissues. J. Appl. Poult, Res., 16: 448-455. https://doi.org/10.1093/japr/16.3.448Benzie I.F.F., Strain J.J. 1996. The ferric reducing ability of plasma (FRAP) as a measure of "Antioxidant Power": The FRAP Assay. Anal. Biochem., 239: 70-76. https://doi.org/10.1006/abio.1996.0292Bulbul A.T., Bulbul S., Kucukersan M., Sireli M., Eryavuz A. 2008. Effect of dietary supplementation of organic and inorganic Zn, Cu and Mn on oxidant/antioxidant balance in laying hens. Kafkas Univ. Vet. Fak., 14: 19-24.Bradford M. 1976. A rapid and sensitive method for the quantitation of microgram quantities of protein utilising the principle of protein-dye binding. Anal. Biochem., 72: 248-254.https://doi.org/10.1016/0003-2697(76)90527-3Casado C., Moya V.J., Pascual J.J., Blas E., Cervera C. 2011. Effect of oxidation state of dietary sunflower oil and dietary zinc and α-tocopheryl acetate supplementation on performance of growing rabbits. World Rabbit Sci., 19: 191-202. https://doi.org/10.4995/wrs.2011.940Cortese M.M., Suschek C.V., Wetzel W., Kroncke K.D., Kolb-Bachofen V. 2008. Zinc protects endothelial cells from hydrogen peroxide via Nrf2-dependent stimulation of glutathione biosynthesis. Free Radic Biol Med., 44: 2002-2012. https://doi.org/10.1016/j.freeradbiomed.2008.02.013Farombi E.O., Hansen M., Raven-Haren G., Moller P., Dragsted L.O. 2004. Commonly consumed and naturally occuring dietary substances affect biomarkers of oxidative stress and DNA damage in the healthy rats. Food Chem. Toxicol., 2: 15-22.Gresakova L., Venglovska K., Cobanova K. 2016. Dietary manganese source does not affect Mn, Zn and Cu tissue deposition and the activity of manganese-containing enzymes in lambs. J. Trace Elem. Med. Biol. 38: 138-143. https://doi.org/10.1016/j.jtemb.2016.05.003Chrastinová Ľ., Čobanová K., Chrenková M., Poláčiková M., Formelová Z., Lauková A., Ondruška Ľ., Pogány Simonová M., Strompfová V., Mlyneková Z., Kalafová A., Grešáková Ľ. 2016. Effect of dietary zinc supplementation on nutrient digestibility and fermentation characteristics of caecal content in physiological experiment with young rabbits. Slovak J. Anim. Sci., 49: 23-31.Ivanišinová O., Grešáková Ľ., Ryzner M., Oceľová V., Čobanová K. 2016. Effects of feed supplementation with various zinc sources on mineral concentration and selected antioxidant indices in tissues and plasma of broiler chickens. Acta Vet. Brno, 85: 285-291. https://doi.org/10.2754/avb201685030285Jo C., Ahn D.U. 1998. Fluorometric analysis of 2-thiobarbituric acid reactive substances in turkey. Poultry Sci., 77: 475-480. https://doi.org/10.1093/ps/77.3.475King J.C., Brown K.H., Gibson R.S., Krebs N.F., Lowe N.M., Siekmann J.H., Raiten D.J. 2016. Biomarkers of nutrition for development (BOND) - Zinc review. J. Nutr., 146: 858S-885S. https://doi.org/10.3945/jn.115.220079King J.C., Shames D.M., Woodhouse L.R. 2000. Zinc homeostasis in humans. J. Nutr., 130: 1360S-1366S. https://doi.org/10.1093/jn/130.5.1360SKwiecien M., Winiarska-Mieczan A., Milczarek A., Klebaniuk R. 2017. Biological response of broiler chickens to decreasing dietary inclusion levels of zinc glycine chelate. Biol. Trace Elem. Res., 175: 204-213. https://doi.org/10.1007/s12011-016-0743-yMa W., Niu H., Feng J., Wang Y., Feng J. 2011. Effects of zinc glycine chelate on oxidative stress, contents of trace elements, and intestinal morphology in broilers. Biol. Trace Elem. Res., 142: 546-556. https://doi.org/10.1007/s12011-010-8824-9Marklund S., Marklund G. 1974. Involvement of the superoxide anion radical in the autoxidation of pyrogallol and a convenient assay for superoxide dismutase. Eur. J. Biochem., 47: 469-474. https://doi.org/10.1111/j.1432-1033.1974.tb03714.xNessrin S., Abdel-Khalek A.M., Gad S.M. 2012. Effect of supplemental zinc, magnesium or iron on performance and some physiological traits of growing rabbits. Asian J. Poult. Sci., 6: 23-30. https://doi.org/10.3923/ajpsaj.2012.23.30Nutritional Research Council (NRC), 1977. Nutrient requirements of rabbits. National Academies of Science, Washington DC, USA.Oteiza P.I. 2012. Zinc and the modulation of redox homeostasis. Free Radic. Biol. Med., 53: 1748-1759. https://doi.org/10.1016/j.freeradbiomed.2012.08.568Paglia D.E., Valentine W.N. 1967. Studies on the quantitative and qualitative characterization of erythrocyte glutathione peroxidase. J. Lab. Clin. Med., 70: 158-169.Powell S.R. 2000. The antioxidant properties of zinc. J. Nutr., 130: 1447S-1454S. https://doi.org/10.1093/jn/130.5.1447SSalomonsson A.C., Theander O., Westerlund O. 1984. Chemical characterization of some Swedish cereals whole meal and bran fractions. Swedish J. Agric. Res. 14: 11-117.Skřivan M., Skřivanová V., Marounek M. 2005. Effects of dietary zinc, iron, and copper in layer feed on distribution of these elements in eggs, liver, excreta, soil, and herbage. Poultry Sci. 84: 1570-1575. https://doi.org/10.1093/ps/84.10.1570Spears, J.W. 1996. Optimizing mineral levels and sources for farm animals. In Kornegay E.T. (ed). Nutrient Management of Food Animals to Enhance and Protect the Environment, CRC Press, Inc., Boca Raton, FL, 259-275.Sunder G.S., Kumar V.C., Panda A.K., Raju M.V.L.N., Rao S.V.R. 2013. Effect of supplemental organic Zn and Mn on broiler performance, bone measures, tissue mineral uptake and immune response at 35 d of age. Curr. Res. Poult. Sci., 3: 1-11. https://doi.org/10.3923/crpsaj.2013.1.11Suttle N.F. 2010. Mineral nutrition of livestock, 4th Edition. CABI Publishing, Wallingford, Oxfordshire, UK. https://doi.org/10.1079/9781845934729.0000Swiatkiewicz S., Arczewska-Wlosek A., Jozefiak D. 2014. The efficacy of organic minerals in poultry nutrition: review and implications of recent studies. World Poultry Sci. J., 70:475-485. https://doi.org/10.1017/S0043933914000531Van Soest P.J., Robertson J.B., Lewis B.A. 1991. Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition. J. Diary Sci., 74: 3583-3597. https://doi.org/10.3168/jds.S0022-0302(91)78551-2Wiseman J., Villamide M.J., De Blas C., Carabaño M.J., Carabaño R.M. 1992. Prediction of the digestible energy and digestibility of gross energy of feed for rabbits. 1. Individual classes of feeds. Anim. Feed Sci. Technol., 39: 27-38. https://doi.org/10.1016/0377-8401(92)90029-6Yan J.Y., Zhang G.W., Zhang C., Tang L., Kuang S.Y. 2017. Effect of dietary organic zinc sources on growth performance, incidence of diarrhoea, serum and tissue zinc concentrations, and intestinal morphology in growing rabbits. World Rabbit Sci., 25: 43-49. https://doi.org/10.4995/wrs.2017.577

Experimental Investigations of a Passive Cooling System Based on the Gravity Loop Heat Pipe Principle for an Electrical Cabinet

This paper deals with the experimental research and verification of a passive cooling system operating on the principle of a loop gravity heat pipe designed for cooling electrical cabinets. This type of cooling works automatically by changing the state of the working substance and thus saves energy consumption. Since the designed cooling system ensures heat transfer from the interior cabinet to the outdoor space, where the heat can naturally dissipate to the surroundings, it is dustproof. The heat pipe consists of an innovative evaporator concept designed to minimize liquid and vapour phase interference in the refrigeration circuit. The aim of the research was to experimentally determine the limit performance parameters of the refrigeration system for different volumes of working medium in the evaporator and decrease heat loss in the cabinet interior. The designed device was verified experimentally and by mathematical calculations as well. The greatest benefit of the work is that the cooling device was able to ensure temperature conditions inside the electrical enclosure at a heat load of 2000 W under 60 &deg;C, 1500 W under 55 &deg;C, 1000 W under 50 &deg;C, 750 W under 45 &deg;C and 500 W under 40 &deg;C

Experimental Investigations of a Passive Cooling System Based on the Gravity Loop Heat Pipe Principle for an Electrical Cabinet

This paper deals with the experimental research and verification of a passive cooling system operating on the principle of a loop gravity heat pipe designed for cooling electrical cabinets. This type of cooling works automatically by changing the state of the working substance and thus saves energy consumption. Since the designed cooling system ensures heat transfer from the interior cabinet to the outdoor space, where the heat can naturally dissipate to the surroundings, it is dustproof. The heat pipe consists of an innovative evaporator concept designed to minimize liquid and vapour phase interference in the refrigeration circuit. The aim of the research was to experimentally determine the limit performance parameters of the refrigeration system for different volumes of working medium in the evaporator and decrease heat loss in the cabinet interior. The designed device was verified experimentally and by mathematical calculations as well. The greatest benefit of the work is that the cooling device was able to ensure temperature conditions inside the electrical enclosure at a heat load of 2000 W under 60 °C, 1500 W under 55 °C, 1000 W under 50 °C, 750 W under 45 °C and 500 W under 40 °C

Design of an experimental device for preheating combustion air

The principle of the proposed device is to use part of the waste heat, which otherwise leaves through the chimney unused into the air, to preheat the combustion air. reducing chimney losses and preheating the combustion air will increase the efficiency of the heat source. the device is actually a gravity loop heat pipe with an evaporating part located behind the furnace and a condensing part in the combustion air supply duct. Heat transfer is realized by means of phase transformation of the working medium in the proposed device

The Effect of Convection on the Thermal Power Change of Loop Thermosyphon

Creating thermal well-being and comfort for humans is now very natural and necessary. From the point of view of ensuring optimal operating conditions for electronic and electrical equipment, it is very important to provide a cooling system. For this reason, the research work deals with the creation of optimal conditions for rising temperatures in rooms with electronics. A combination of cooling systems is proposed to reduce the heat load of electronic components. The first part of the work generally describes the requirements for the design of refrigeration equipment and methods of heat dissipation by natural or forced convection. Depending on the requirement for low-energy equipment, a cooling system with a gravitational heat pipe and fans was designed in the second part of the work. The cooling system was installed in a closed electrical cabinet. The resulting values of the measurements indicated the evaluation of the transferred heat output in free and forced convection. The research also points to a comparison of the individual flow directions created by the fans

Machine learning model designed to predict the amount of CO

Emissions, including CO2 emissions, are generated during the combustion process. Perfect combustion of biomass should not lead to the formation of CO, but all carbon should burn perfectly and change to CO2 by the oxidation process. Under real conditions, complete combustion never occurs and part of the carbon is not burned at all or only imperfectly to form CO. The aim of the work was to create a prediction model of machine learning, which allows to predict in advance the amount of CO2 generated during the combustion of wood pellets. This model uses machine learning regression methods. The most accurate model (Gaussian process) showed a root-mean-square error, RMSE = 0.55. The resulting mathematical model was subsequently verified on independent measurements, where the ability of the model to correctly predict the amount of CO2 generated in % was demonstrated. The average deviation of the measured and predicted amount of CO2 represented a difference of 0.53 %, which is 8.8 % of the total measured range (3.08 - 9.2). Such a model can be modified and used in the prediction of other combustion parameters