Resorpcija magnezija u distalnom dijelu svinjskog probavila u obostrano izotoničnim i izoioničnim uvjetima.

The effect of low magnesium concentrations in composed isotonic and isoionic Tyrode’s solution on its absorption from the distal part of the swine digestive tract was investigated in vitro on bags made of survived epithelia of the swine caecum and proximal colon. The epithelial side of either epithelium was always turned into the bags that were filled with Tyrode’s solution containing 0.5, 1.0 or 2.5 mmol/L magnesium. Tyrode’s solutions were always situated outside the bags, i.e., from submucosal side of the epithelium. At the beginning of the experiment and after 30, 60, 120 and 180 minutes of the experiment samples were taken from the solution outside the bags and analyzed spectrophotometrically for magnesium concentration. The excess of magnesium contents in the solution obtained in each experimental interval represents “the net flux” of magnesium in the direction of absorption. According to the results of the experiment, magnesium may be absorbed from both caecum and proximal colon epithelia against the concentration gradient, as well as under isotonic and isoionic conditions from both sides of the epithelium. The intensity of magnesium absorption depended on its concentration in the contents, on the epithelium used, and on the time of sampling. Results indicate the distal part of the swine digestive tract as the important part for magnesium absorption, especially under low concentrations in the contents. Under these experimental conditions the passive transport of magnesium played the major part.Istražen je utjecaj niskih koncentracija magnezija u složenoj izotoničnoj i izoioničnoj Tyrodeovoj otopini na njegovu resorpciju u distalnom dijelu svinjskog probavila. Istraživanja su obavljena in vitro metodom vrećica, načinjenih od preživjele sluznice svinjskog slijepog crijeva i proksimalnog kolona. Epitelnom stranom sluznica je bila okrenuta u unutrašnjost vrećice koje su potom bile napunjene Tyrodeovom otopinom u kojoj je koncentracija magnezija iznosila 0,5, 1,0 ili 2,5 mmol/L. S vanjske, submukozne, strane sluznice crijeva redovito se nalazila Tyrodeova otopina iz koje su, neposredno prije početka pokusa i nakon pokusnog razdoblja od 30, 60, 120 i 180 minuta uzeti uzorci za spektrofotometrijsko određivanje magnezija. Višak magnezija u svakom pokusnom razdoblju predstavljao je »neto prolaz« magnezija smjerom resorpcije. Prema dobivenim rezultatima magnezij se u svinjskom slijepom crijevu i proksimalnom kolonu može resorbirati nasuprot koncentracijskom gradijentu, kao i u obostrano izotoničnim i izoioničnim uvjetima. Intenzitet resorpcije magnezija ovisio je o njegovoj koncentraciji u sadržaju, upotrijebljenoj sluznici te o vremenskom razmaku. Dobiveni rezultati upućuju da distalni dio svinjskog probavila predstavlja važno mjesto resorpcije magnezija pri njegovim niskim koncentracijama u sadržaju, pri čemu se magnezij u tim uvjetima najvećim dijelom resorbirao pasivnim prijenosom

Kretanje koncentracije hormona štitaste žlijezde u krvnoj plazmi pilića tijekom tova.

Thyroid hormones concentration changes in blood plasma of 30 male hybrid chickens of the heavy Ross breed were studied during broilers’ fattening period. Blood samples were collected in heparinised tubes after decapitation of chickens at 28, 35 and 42 days of age. Blood plasma was separated by centrifugation and concentration of thyroid hormones triiodothyronine (T3) and thyroxin (T4) was determined by the RIA method. Concentration of both hormones gradually increased during the experiment following the broilers\u27 fattening process. However, only the increase of T3 concentration was statistically significant. This rise was related to its involvement in metabolic processes, particularly in processes of biooxidation. Different dynamics in concentration changes of investigated hormones may be related to an increase in thyroid gland secretion as well as the peripheral conversion of T4 to the reversible T3 (rT3).Na pilićima pasmine Ross istraženo je kretanje koncentracije hormona štitaste žlijezde trijodtironina(T3) i tiroksina (T4) u krvnoj plazmi tijekom tova. Za pokus je odabrano 30 muških pilića. Krv za analizu uzimana je 28., 35. i 42. dan starosti netom nakon dekapitacije uz upotrebu heparina kao antikoagulansa. U izdvojenoj krvnoj plazmi odre|ena je koncentracija hormona RIA metodom. Rezultati pokusa pokazali su kako koncentracija oba hormona u krvnoj plazmi raste tijekom pokusnog razdoblja, ali je taj porast statistički značajan samo za T3. Dobiveni rezultati ukazuju kako koncentracija istraživanih pokazatelja prati tijek tova. Značajniji porast koncentarcije trijodtironina u krvnoj plazmi pilića dovodi se u vezu s njegovom značajnijom ulogom u metabolizmu, osobito u procesima biooksidacije. Nadalje se pretpostavlja kako porast istraživanih hormona pokazuje i veću aktivnost štitaste žlijezde u periodu tova. Pri tome koncentracija T4 predstavlja isključivo odraz aktivnosti štitaste žlijezde, dok koncentracija T3 može ovisiti o aktivnosti žlijezde, ali i konvertiranju T4 u T3 u cirkulaciji

Utjecaj dobi i spola na odabrane hematološke i biokemijske pokazatelje u janjadi pasmine dalmatinska pramenka

The objective of the present study was to determine the influence of age and sex on selected haematological and blood biochemical parameters in organically raised Dalmatian Pramenka lambs. Haematological and blood biochemical parameters were studied in 40 lambs with an equal representation of both sexes. The research lasted four months. Blood samples were collected once per month, from the beginning of the grazing season when lambs were at the average age of three months, and until the end of the production cycle for lamb meat. The distribution of the results according to age showed that the increase in the age of the lambs significantly reduced (P<0.05) the RBC, HGB, HCT and the concentration of GLU, BUN, BIT. The concentration of TP, ALB, GLO and the activity of enzyme AST significantly increased (P<0.05) with the increasing age of the lambs. The distribution of results by sex showed that female lambs had significantly higher WBC (P<0.05), RBC (P<0.01), and HGB (P<0.05) concentration, while male lambs had significantly higher values of MCV (P<0.01) and concentration of FFA (P<0.01). In conclusion, this research demonstrated that age and sex significantly influence most of the haematological and blood biochemical parameters of organically raised Dalmatian Pramenka lambs.Cilj rada bio je istražiti utjecaj dobi i spola na odabrane pokazatelje u krvi janjadi pasmine dalmatinska pramenka uzgajane u ekološkim uvjetima. Četrdeset janjadi u prosječnoj dobi od tri mjeseca, s ravnomjernom zastupljenošću oba spola, obuhvaćeno je istraživanjem koje je uspostavljeno s početkom sezone izlaska na pašu (ožujak), a trajalo je do kraja proizvodnog ciklusa uzgoja janjadi za klanje (lipanj), ukupno četiri mjeseca. Uzorci krvi za hematološku i biokemijsku pretragu uzimani su svakog mjeseca (u četiri navrata) u razmaku od 30 dana. Raspodjela rezultata hematoloških i biokemijskih pokazatelja u krvnom serumu prema dobi janjadi, pokazala je da je povećanje dobi janjadi pratilo statistički znakovito smanjenje (P<0,05) koncentracije RBC, HGB, HCT, GLU, BUN i BIT te povećanje (P<0,05) koncentracije TP, ALB, GLO i aktivnosti enzima AST. Raspodjela rezultata prema spolu janjadi, pokazala je da je ženska janjad imala statistički znakovito veći WBC (P<0,05), RBC (P<0,01), HGB (P<0,05) od muške janjadi, dok je muška janjad imala veći MCV (P<0,01) i koncentraciju FFA (P<0,01) u usporedbi s ženskom janjadi. Zaključeno je da dob i spol znakovito utječu na promjene vrijednosti većine hematoloških i biokemijskih pokazatelja u serumu janjadi dalmatinske pramenke iz ekološkog uzgoja

Utjecaj gladovanja na aktivnost glukoneogenih enzima u jetri i bubrezima pačića.

Blood glucose concentration, liver and kidney gluconeogenic enzyme activities were investigated during a six-day fasting period in ducklings (English heavy breed Peking Duck). Food deprivation commenced when ducklings reached the age of twenty-eight days. Normally fed ducklings were used as a control group. The ducklings were sacrificed by decapitation after a fasting period of three, four, five and six days, and blood and tissue samples were collected from both groups for analysis. During the experiment the concentration of blood glucose was above 6 mmol/L in both the control and experimental groups, except on experimental day three. Significant rises in glucose-6-phosphatase (EC 3.1.3.9) (G6Pase) activities in the liver were observed on starvation days four, five and six (P = 0.0012, P = 0.0109, P = 0.0279), and in the kidney on starvation days five and six (P = 0.0373, P = 0.0206, respectively). Hepatic fructose-1.6-bis-phosphatase (EC 3.1.3.11) (FDPase) activity showed a significant difference between the fasted and control group only after a four-day fast (P = 0.0491), whereas renal enzyme activity increased after four (P = 0.0279) and six (P = 0.0373) days of food deprivation. Phosphoenolpyruvate carboxykinase (EC 4.1.1.32) (PEPCK) activity in the liver of fasted ducklings significantly decreased on fasting day five (P = 0.0012), whereas in the kidney a significant rise in four-day fasted animals (P = 0.032) was observed in comparison with the normally fed controls. The results showed that ducklings are able to maintain blood glucose concentration during a six-day fasting period. Changes in gluconeogenic enzyme activities indicate the important role of liver and renal gluconeogenesis for the maintenance of blood glucose concentration in fasted ducklings. These findings agree with earlier data obtained on chicken, thus confirming the similarities between the two avian species regarding the maintenance of blood glucose level with the process of gluconeogenesis during longer fasting.Istraživana je koncentracija glukoze u krvi i aktivnost glukoneogenih enzima u jetri i bubregu pekinških pačića (English heavy breed Peking Duck) tijekom šestodnevnog gladovanja, koje je započeto s navršena četiri tjedna života. Normalno hranjeni pačići služili su kao kontrolna skupina. Pačići su bili žrtvovani dekapitacijom nakon trećeg, četvrtog, petog i šestog dana istraživanja, a krv i uzorci tkiva za analize sakupljani su istovremeno od obje skupine. Tijekom istraživanja, osim trećeg dana, koncentracija glukoze u krvi kontrolne i pokusne skupine bila je veća od 6 mmol/L. Značajan porast aktivnosti glukoze-6-fosfataze (EC 3.1.3.9) (G6Pase) u jetri ustanovljen je četvrtog, petog i šestog dana gladovanja (P = 0.0012, P = 0.019, P = 0.0279), a u bubrezima petog i šestog dana gladovanja (P = 0.0373, P = 0.0206). Aktivnost fruktoze-1,6-bis fosfataze (EC 3.1.3.11) (FDPase) u jetri bila je značajno veća u pokusne nego u kontrolne skupine samo četvrtog dana gladovanja (P = 0.0491), dok je u bubrezima porasla četvrtog (P = 0.0279) i šestog (P = 0.0373) dana gladovanja. Aktivnost fosfoenolpiruvat karboksikinaze (EC 4.1.1.32) (PEPCK) u jetri pačića značajno je pala petog dana gladovanja (P = 0.0012), dok je u bubrezima značajno porasla četvrtog dana gladovanja (P = 0.032). Rezultati su pokazali da pačići s navršena četiri tjedna života mogu održavati koncentraciju glukoze u krvi tijekom šestodnevnog gladovanja. Promjene u aktivnostima glukoneogenih enzima upućuju na važnu ulogu procesa glukoneogeneze u jetri i bubrezima za održavanje normoglikemije pačića koji gladuju. Takvi nalazi slažu se s dobro poznatim podacima za piliće, što pokazuje da postoji sličnost između te dvije ptičje vrste u održavanju razine glukoze u krvi procesom glukoneogeneze tijekom dužeg gladovanja

Kretanje koncentracija ukupnih bjelančevina i njihovih frakcija u krvnom serumu pilića tijekom tova

This paper describes research into concentration of total proteins and individual protein fractions in the blood serum of Ross broiler chickens during fattening period. Blood for analysis was taken at the 14th, 28th and 42nd days of age by wing vein puncture. Concentration of total serum proteins was detected by spectrophotometry. Electrophoresis on gelled cellulose-acetate tapes determined the shares of individual fractions: albumins, alpha 1-, alpha 2-, beta 1-, beta 2- and gamma globulins, and their absolute concentrations were calculated from the concentration of total proteins. A statistically significant growth of total proteins concentration was established during the experiment (P<0.0001). Changes of concentration of individual fractions did not always follow the quantity of total proteins in the blood serum. Concentration of albumins in blood did not show oscillations during fattening, unlike alpha 1-globulins, whose concentration showed a statistically significant increase by the 28th day of fattening (P<0.0001), and which then decreased considerably by the 42nd day compared to the 28th day (P<0.05). Concentration of alpha 2-globulins did not show significant growth until the 42nd day in comparison to the 14th day (P<0.01). Fractions of beta 1-, beta 2- and gamma globulins showed a significant increase during all trial periods (from P<0.05 to P<0.0001). The ratio of albumins to globulins showed a statistically significant decrease on the 28th and the 42nd days, compared to the 14th day of the experiment (P<0.0001). The given results are related to the role of protein metabolism in the rapid growth of chickens during fattening, and may serve as part of metabolic profile in evaluation of production patterns and health condition of chickens during fattening.Istraženo je kretanje koncentracija ukupnih bjelančevina i pojedinih frakcija bjelančevina u krvnom serumu tovnih pilića hibridne linije Ross. Krv za analizu uzimana je 14., 28. i 42. dana starosti, punkcijom krilne vene. Spektrofotometrijski je određena koncentracija ukupnih bjelančevina u krvnom serumu. Elektroforezom su određeni udjeli pojedinih frakcija: albumina, alfa 1-, alfa 2-, beta 1-, beta 2- i gama-globulina, a njihove apsolutne koncentracije izračunate iz ukupne koncentracije bjelančevina. Tijekom pokusa utvrđen je statistički značajan porast koncentracije ukupnih bjelančevina (P<0,0001). Kretanja koncentracija pojedinih frakcija nisu uvijek pratila ukupnu količinu bjelančevina u krvnom serumu. Koncentracija albumina u krvi nije kolebala tijekom tova, za razliku od alfa 1-globulina, čija je koncentracija statistički značajno porasla do 28. dana tova (P<0,0001), a potom značajno pala do 42. dana u odnosu na 28. dan (P<0,05). Koncentracija alfa 2-globulina značajno je porasla tek 42. dana u odnosu na 14. dan (P<0,01). Frakcije beta 1-, beta 2- i gama-globulina pokazale su značajan porast tijekom svih istraživanih razdoblja (od P<0,05 do P<0,0001). Omjer albumina prema globulinima bio je statistički značajno snižen 28. i 42. dana u odnosu na 14. dan pokusa (P<0,0001). Dobiveni rezultati dovode se u vezu s ulogom metabolizma bjelančevina u brzom prirastu tovnih pilića i mogli bi poslužiti kao dio metaboličkog profila, u procjeni proizvodne sposobnosti, kao i zdravstvenog stanja pilića tijekom tova

Utjecaj dodatka organskog selena u hrani i gladovanja na oksidativna oštećenja različitih tkiva pilića.

The influence was investigated of organic selenium feed supplements on lipid peroxidation and protein oxidation in different tissues of Ross 308 broiler chickens of both sexes in response to 48 hours food deprivation. Chickens were randomly allocated into a standard diet fed control group (N = 50) and an experimental group, pair-fed with the same diet supplemented with 0.3 ppm organic selenium (Sel-Plex®, Alltech, Inc., KY; N = 50). At the age of 42 days and after 48 hours food deprivation, ten chickens from the experimental group and ten chickens from the control were sacrificed and the liver, kidneys and small intestines were removed. Liver, small intestine and kidney tissue homogenates were analysed for lipid peroxide concentrations (LPO) and protein carbonyl content (PCC). The PCC in kidney and small intestine of experimental chickens at the end of the fattening period was higher than in the control broilers (P<0.05). As a result of the food deprivation, lower PCC was found in the liver of both groups (P<0.05). Simultaneously, the values for the experimental group were lower than in the control group (P<0.05). Kidney PCC was only increased after fasting in the control birds (P<0.05). The LPO in the kidneys at the end of fattening was higher in chickens fed diet supplemented with organic selenium (P<0.05). Kidney and small intestine tissue LPO of both groups was decreased after fasting (P<0.05). At the same time the LPO in the liver of the experimental group was increased (P<0.05). The results of this study demonstrate that dietary organic selenium supplements increase oxidative damage in the kidneys and small intestines at the end of fattening. Food deprivation resulted in decreased tissue oxidative damage due to the lower metabolic rate.U radu je istražen utjecaj dodatka organskog selena u hrani na lipidnu peroksidaciju i oksidaciju proteina različitih tkiva Ross 308 tovnih pilića oba spola izloženih 48-satnom gladovanju. Pilići su nasumično bili podijeljeni u kontrolnu skupinu (n = 50) hranjenu standardnom hranom za piliće i pokusnu skupinu hranjenu jednakom hranom u koju je dodano 0,3 ppm organskog selena (Sel-Plex®, Alltech, Inc., KY; n = 50). U dobi od 42 dana i nakon 48-satnog gladovanja deset životinja iz obje skupine bilo je usmrćeno te su uzeti uzorci jetre, bubrega i tankoga crijeva. U homogenatima tkiva određena je koncentracija lipidnih peroksida (LPO) i oksidiranih proteina (PCC). Koncentracija PCC u bubrezima i tankom crijevu pokusnih pilića na kraju tova bila je veća nego u kontroli (P<0,05). Nakon gladovanja, u jetri je utvrđena niža koncentracija PCC u obje grupe (P<0,05). Istovremeno, koncentracija PCC u jetri pilića bila je niža u pokusnoj skupini u odnosu na kontrolu (P<0,05). Bubrežni PCC bio je povišen nakon gladovanja kod kontrolnih pilića (P<0,05). Koncentracija LPO u bubrezima pokusnih pilića na kraju tova bila je veća nego u kontroli (P<0,05). Koncentracija LPO u bubrezima i tankom crijevu obiju skupina nakon gladovavnja se smanjila (P<0,05) dok je u jetri pokusne skupine bilapovećana (P<0,05). Rezultati istraživanja pokazuju da dodatak organskog selena u hrani uzrokuje oksidativna oštećenja u bubrezima i tankom crijevu pilića na kraju tova. Gladovanje smanjuje stupanj oksidativnih oštećenja zbog smanjenja intenziteta metabolizma

Učinak dodavanja organskoga selena u hranu na aktivnost antioksidativnih enzima i lipidsku peroksidaciju u srčanom mišiću pilića tijekom tova

The effect of organic selenium feed supplements on the activities of antioxidant enzymes and on lipid peroxidation was investigated in chickens’ heart muscles during growth. The experiment was carried out on Ross 308 broiler chickens of both sexes, either on standard diet (control) or receiving organic selenium supplementation in the standard diet (experimental). After two, four and six weeks of growth, ten chickens from each group were sacrificed by decapitation and heart muscles were collected for analyses. In the heart muscle the activities of glutathione peroxidase (GSH-Px), catalase (CAT), cooper zinc superoxide dismutase (Cu,Zn- SOD), manganese superoxide dismutase (Mn-SOD), reduced glutathione (GSH) and lipid peroxide (TBARS) were determined. During the experiments, age-related differences of antioxidant enzyme activities and GSH and TBARS concentrations were obtained in control and in experimental chicken. At the end of growth, after the 6th week of age, a significant increase of GSH-Px, Cu,Zn-SOD, and CAT activities (P<0.001; P<0.001; P<0.05) with a significant decrease of Mn-SOD activity and GSH concentration (P<0.01; P<0.01) were obtained in the heart muscle of the experimental chickens. In the control chickens, signifi cant increases of GSH-Px, Cu,Zn- SOD and TBARS (P<0.001; P<0.001; P<0.01) with a significant decrease of GSH concentration (P<0.05) were obtained in the heart muscle after six weeks of age. After the fourth week of age, chickens with organic selenium supplementation had a significantly higher activity of GSH-Px, Cu,Zn-SOD, and Mn-SOD (P<0.001; P<0.05; P<0.05) than the control chickens of the same age. In conclusion, chickens with organic selenium supplementation in the diet maintained their antioxidant systems in the heart muscle more effectively, with enhanced antioxidant defence.Istražen je učinak dodavanja organskoga selena u hranu na aktivnost antioksidativnih enzima i na intenzitet lipidske peroksidacije u srčanom mišiću pilića tijekom tova. Istraživanja su načinjena na pilićima hibridne linije Ross 308 koji su tijekom tova hranjeni standardnim smjesama (kontrolna skupina) i na pilićima kojima je tijekom tova u standardnu smjesu dodano 0,3 ppm organskoga selena (pokusna skupina). Po deset nasumce odabranih pilića kontrolne i deset pilića pokusne skupine žrtvovano je dekapitacijom u dobi od dva, četiri i šest tjedana. Odmah po žrtvovanju životinja uzeti su uzorci srčanoga mišića u kojima su određene aktivnosti glutation peroksidaze (GSH-Px), katalaze (CAT), bakar cink superoksid dismutaze (Cu,Zn-SOD) i manganske superoksid dismutaze (Mn-SOD) te koncentracija reduciranog glutationa GSH) i intenzitet lipidske peroksidacije (TBARS). Tijekom tova pilića utvrđene su značajne razlike aktivnosti antioksidativnih enzima te koncentracija GSH i TBARS kod obje skupine pilića. Po završetka tova, u dobi od šest tjedana, utvrđen je značajan porast aktivnosti GSH-Px, Cu,Zn-SOD i CAT (P<0,001; P<0,001; P<0,05) uz značajno smanjenje Mn- SOD i GSH (P<0,01; P<0,01) u srčanom mišiću pokusne skupine pilića. Istodobno je u srčanom mišiću kontrolne skupine pilića utvrđen značajan porast GSH-Px, Cu,Zn-SOD i TBARS (P<0,001; P<0,001; P<0,01) te značajno smanjenje koncentracije GSH (P<0,05). Značajno viša aktivnost GSH-Px, Cu,Zn-SOD i Mn-SOD (P<0,001; P<0,05; P<0,05) u srčanom mišiću pokusne skupine pilića u dobi od četiri tjedna upućuje na pozitivan učinak organskoga selena, koji u konačnici može rezultirati boljom antioksidativnom zaštitom srčanoga mišića

Utjecaj dodavanja organskoga selena u hranu na antioksidativna svojstva i lipidsku peroksidaciju u krvi pilića tijekom tova i nakon gladovanja

Selenium is an essential trace element in human and animal nutrition and an integral component of antioxidative proteins. Organic selenium, a natural form of selenium, has more beneficial effects in maintaining antioxidative system than its inorganic form. The objective of this study was to examine the effect of organic selenium food supplements on the level of glutathione peroxidase (GSH-Px), glutathione (GSH) and lipid peroxides (TBARS) in chicken whole blood. Chickens were randomly allocated into two groups: standard diets (<0.15 ppm sodium selenite) fed control group (n = 40) and Se+ group (n = 40), fed the same diets supplemented with 0.3 ppm organic selenium. Ten randomly selected birds from each group at the age of two, four and six weeks and after 48-hours of food deprivation at the end of the fattening period, were subjected to blood withdrawal from jugular vein. The GSH-Px activity and concentrations of GSH and TBARS were analyzed by spectrophotometry. A trend was observed toward increasing GSH-Px in the blood of the control group from two to six weeks of age (P<0.001), whereas in the Se+ group the increase was obtained in the first four weeks (P<0.01). GSH-Px activity after fasting was lower only in the control chickens (P<0.01). Organic selenium supplementation resulted in higher GSH-Px activity at two and four weeks of age (P<0.01), as well as after fasting (P<0.01). The GSH level in four week old Se+ chickens was lower than in two and six week old broilers (P<0.01). At the same time, in the two week old control chickens higher values were recorded in comparison with older birds (P<0.05). After fasting, the GSH was lower in both groups of chickens compared to values given after the end of the fattening period (P<0.001). The TBARS decreased in concentration in both groups at six weeks of age compared to younger chickens (P<0.05). Dietary organic selenium supplementation manifested higher activity of GSH-Px during fattening and maintaining its activity in stress conditions provoked by fasting.Selen je esencijalni element u hranidbi životinja zbog svojih antioksidativnih značajki. Organski selen, prirodni oblik selena, pokazuje bolje učinke u održavanju antioksidativnog statusa životinja nego anorganski selen. U radu je istražen utjecaj dodavanja organskoga selena u hranu na aktivnost glutation peroksidaze (GSHPx), koncentraciju glutationa (GSH) i jačinu lipidske peroksidacije (TBARS) u krvi pilića tijekom tova i nakon 48-satnog gladovanja. Kontrolna skupina (n = 40) hranjena je standardnom hranom (min. 0,15 ppm natrijeva tova pilića u dobi od dva, četiri i šest tjedana, te nakon 48-satnog gladovanja uzeta je krv iz jugularne vene s heparinom kao antikoagulansom od po deset pilića Se+ i kontrolne skupine. Spektrofotometrijski određena je aktivnost GSH-Px te koncentracije GSH i TBARS. Aktivnost GSH-Px u krvi kontrolnih pilića rasla je s dobi (P<0,001) tijekom cijeloga istraživanja, dok je u Se+ pilića porast zabilježen u prva četiri tjedna starosti (P<0,01). Gladovanje je samo u kontrolnih pilića izazvalo pad aktivnosti GSH-Px (P<0,01). Dodatak organskoga selena doveo je do viših aktivnosti GSH-Px u Se+ pilića starih dva i četiri tjedna (P<0,01) kao i nakon 48-satnoga gladovanja (P<0,01) u odnosu na kontrolne piliće. Koncentracija GSH u Se+ pilića starih četiri tjedna bila je niža nego u pilića starih dva i šest tjedana (P<0,01), dok se u kontrolnih smanjivala s dobi (P<0,05). Gladovanje je dovelo do pada GSH u obje skupine pilića (P<0,001). Koncentracija TBARS u šest tjedana starih pilića obje skupine se smanjila u usporedbi s mlađim pilićima (P<0,05). Dodatak organskoga selena doveo je do porasta aktivnosti GSH-Px sa starošću uz održavanje aktivnosti u stresu izazvanom gladovanjem