The effect of hybrid COBB 500 broiler parents' age and egg storage period length on chicken incubation efficiency

U cilju utvrđivanja produktivnih i reproduktivnih osobina brojlerskih roditelja hibrida Cobb 500 sprovedena su istraživanja na jednom matičnom jatu koje je gajeno od 23. do 60. nedelje starosti (38 nedelja). U toku istraživanja praćeni su sledeći proizvodno – reproduktivni parametri: intenzitet nosivosti jaja različitih kategorija, mortalitet i vitalnost roditeljskih parova, utrošak hrane po grlu i proizvedenom jajetu. Posebna pažnja data je reproduktivnim osobinama, tj. proizvodnji jednodnevnih brojlerskih pilića, kao finalnog proizvoda. Osnovni cilj rada bio je utvrđivanje uticaja pojedinih paragenetskih faktora na rezultate inkubacije, u prvom redu, starosti brojlerskih roditelja (SR) i perioda skladištenja jaja, odnosno starosti jaja (SJ). U tri faze proizvodnog ciklusa gajenja, odnosno različite starosti brojlerskih roditelja (SR25, SR41 i SR58) i kod jaja skladištenih do 7 i preko 7 dana (SJ7) utvrđeni su: masa jaja različitih kategorija, oplođenost jaja, izvodljivost pilića, embrionalni mortalitet u toku inkubacionog perioda (rani, srednji i kasni), masa jednodnevnih pilića, relativni udeo pileta u masi jajeta, kao i fenotipska korelaciona (rp) povezanost između većine praćenih reproduktivnih pokazatelja. Pored osnovnih produktivnih i reproduktivnih parametara utvrđivan je uticaj starosti brojlerskih roditelja po fazama proizvodnog ciklusa i dužine skladištenja, odnosno starosti jaja na embrionalni razvoj pilića i rezultate inkubacije. Posmatrano po fazama gajenja, brojlerski roditelji su najbolje proizvodne, odnosno reproduktivne vrednosti pokazali sredinom proizvodnog ciklusa (SR41), u odnosu na početnu (SR25) i završnu fazu (SR58) produkcije jaja za nasad. U tom periodu po useljenoj nosilji proizvedeno je 5,08 jaja, 4,74 oplođenih jaja, 4,40 jednodnevnih pilića, dok je prosečan dnevni utrošak hrane po useljenom grlu iznosio 181,00 g. Prosečna masa jaja skladištenih do 7 dana je bila u optimalnim granicama, i iznosila je 63,11 g., oplođenost jaja iznosila je 97,43%, leženost pilića 87,62% (od inkubiranih jaja), odnosno 89,93% (od oplođenih jaja). Masa jednodnevnih pilića bila je na zadovoljavajućem nivou (44,02 g) i relativni udeo pileta u masi jajeta iznosio je 69,73%. Pored toga, starost brojlerskih roditelja je uticala na povećanje mase jaja (P<0,001) i izleženih pilića (P<0,001), dok se procenat pileta u masi jajeta smanjivao, a period skladištenja jaja, kod sve tri faze proizvodnog ciklusa, negativno je uticao na procenat pileta, tj. sa produžavanjem perioda skladištenja jaja, relativni udeo pileta u masi jajeta se smanjivao, posebno u početnoj (SR25) i završnoj fazi (SR58) proizvodnog ciklusa (P<0,001).The research was conducted on one breeding flock of hybrid Cobb 500 broiler parents bred in the interval between 23rd and 60th week of age with the objective of determining their production and reproduction characteristics. The following production – reproduction parameters were inspected: carrying capacity of different category eggs, mortality and vitality of parents couples, the consumption of food per head and per egg produced. Special attention was paid on reproduction characteristics, i.e. on the production of diurnal broiler chicken as a final product. The main objective of this doctoral dissertation was to determine the effect of certain paragenetic factors, primarily broiler parents’ age (PA) and storage eggs period i.e. eggs age (EA), on incubation results. In the course of the three stages of production breeding cycle, i.e. regarding different age of broiler parents (PA25, PA41 and PA58) and regarding eggs stored up to seven and over seven days (EA7), the following was substantiated: different category eggs mass, the degree of fertilization of eggs, chicken feasibility, embryo mortality during incubation period (early, middle, late), diurnal chicken mass, the relative proportion of chicken in the egg mass, and phenotype correlative (rp) relatedness among the majority of observed reproduction indicators. Beside basic production and reproduction parameters, the effect of broiler parents’ age during the stages of the production cycle and storage period length i.e. eggs age on chicken embryo development and incubation results was substantiated. Observing each breeding stage, broiler parents showed the best production and reproduction values in the middle of the production cycle. Namely, compared to the initial (PA25) and final (PA58) stage of clutch eggs production, broiler parents had the best production and reproduction characteristics in the middle of the production cycle (PA41). In this period, 5.08 eggs, 4.74 fertilized eggs and 4.40 diurnal chickens were produced per occupied layer hen, whereas the average daily consumption of food was 181.00 g per occupied head. The average mass of eggs stored up to seven days was 63.11 g, which falls within the optimal boundaries, the fertilization of eggs was 97.43%, chicken hatching was 87.62% among incubated eggs and 89.93% among fertilized eggs. Diurnal chicken mass was on a satisfying level (44.02 g) and a relative proportion of chicken in the egg mass was 69.73%. Besides, broiler parents’ age caused the egg mass increase (P<0.001) and hatched chicken increase (P<0.001), whereas the percentage of chicken in the egg mass decreased. Egg storage period, in each of the three stages of the production cycle, negatively affected the chicken percentage: with the prolongation of egg storage period, the relative proportion of chicken in egg mass was reduced, especially in the initial (PA25) and final (PA58) stage of production cycle (P<0.001)

Prisustvo stres sindroma (PSS) kod svinja rase mangulica

Porcine stress syndrome (PSS) is one kind of molecular genetics defect which will cause malignant hyperthermia syndrome in pigs. It was reported that mutation of pig rynodine receptor (RYR1) gene is the main reason for PSS. The aim of this study was to test the RYR1 genotype of 10 Mangalitsa pigs using a polymerase chain reaction-restriction endonuclease fragment length polymorphism (PCR-RFLP) technique, which is a reliable and simple method for RYR1 gene testing. Extraction of DNA was done by using hair follicles. The results showed that the RYR1 genotype of all the 10 porcine cases were negative. These results suggested that Mangalitsa pig could be one of the porcine breeds selectively bred for medical and clinically experiments.Stres sindrom svinja (PSS - Porcine Stress Syndrome) pripada genetskim oboljenjima svinja i može da izazove sindrom maligne hipertermije. Utvrđeno je da je mutacija rijanodin receptora (RYR1) gena svinja glavni razlog za pojavu PSS-a. Cilj ovog ogleda bio je testiranje RYR1 gena na 10 svinja rase mangulica korišćenjem PCR-restriktivnog endonukleaza testa (PCR-RFLP), koji predstavlja jednostavnu i pouzdanu tehniku za testiranje RYR1 gena. Ekstrakcija DNK je obavljena korišćenjem korena dlake svinja. Rezultati ogleda potvrđuju da je RYR1 genotip kod svih 10 svinja bio negativan. Na osnovu napred navedenog može se zaključiti da bi mangulica mogla da bude jedna od genotipova koji se koriste za medicinska i klinička ispitivanja

Environmental Education in Serbian Primary Schools: Challenges and Changes in Curriculum, Pedagogy, and Teacher Training

The protection of human health and the preservation of the environment are topics that form anintegral part of the primary school curriculum in Serbia. However, research studies have shown thatstudents do not have enough knowledge to contribute to the development of a healthy lifestyle andenvironmental awareness. The latest changes in school policy and curricula confirm that the relevanceof environmental education has been recognized, but changes in school practice are yet to come. Thisarticle discusses the challenges encountered in the implementation of the intended curriculum andoffers suggestions for changes to the curriculum, pedagogy, and teacher training in order to enhanceenvironmental educationThis is the peer-reviewd version of the artivle: Stanišić, Jelena, и Slavica Maksić. 2014. „Environmental Education in Serbian Primary Schools: Challenges and Changes in Curriculum, Pedagogy, and Teacher Training“. Journal of Environmental Education 45(2):118–31. doi: 10.1080/00958964.2013.829019.Related to published version: [ http://ipir.ipisr.org.rs/handle/123456789/240

Qualitative properties of traditionally produced dry fermented sausages from meat of the autochthonous Mangalitsa pig breed

The interest in autochthonous meat products from local pig breeds managed in comprehensive, sustainable breeding programs is expanding in Europe. Dry fermented sausages in Serbia and other southern European countries are highly appreciated food specialties. It is, therefore, desirable that study attempts to improve the quality of food and the security of traditional, dry sausages will result in products that are of higher added value and have quality standards that best meet the needs of contemporary customers. Meat and meat products from traditional pig breeds usually have an excellent public and media reputation, and are often regarded as better than the meat and meat products of conventionally raised pigs and crossbreed pigs. Traditional, dry fermented sausages, with their characteristic chemical contents and sensory properties, can be produced with suitable proportions of meat and backfat from the indigenous Mangalitsa pig breed. These outcomes should hopefully encourage the sustainable breeding of endangered Mangalitsa pigs, as there are market opportunities for kulen and sremska sausages

Evidence of West Nile virus (WNV) circulation in wild birds and WNV RNA negativity in mosquitoes of the Danube Delta Biosphere Reserve, Romania, 2016

West Nile virus (WNV) is a zoonotic flavivirus whose transmission cycle in nature includes wild birds as amplifying hosts and ornithophilic mosquito vectors. Bridge vectors can transmit WNV to mammal species potentially causing West Nile Fever. Wild bird migration is a mode of WNV introduction into new areas. The Danube Delta Biosphere Reserve (DDBR) is a major stopover of wild birds migrating between Europe and Africa. The aim of this study was to investigate the presence of WNV in the DDBR during the 2016 transmission season in wild birds and mosquitoes. Blood from 68 wild birds (nine different species) trapped at four different locations was analyzed by competitive ELISA and Virus Neutralization Test (VNT), revealing positive results in 8/68 (11.8%) of the wild birds by ELISA of which six samples (three from juvenile birds) were confirmed seropositive by VNT. Mosquitoes (n = 6523, 5 genera) were trapped with CDC Mini Light traps at two locations and in one location resting mosquitoes were caught. The presence of WNV RNA was tested in 134 pools by reverse transcription quantitative PCR (RT-qPCR). None of the pools was positive for WNV-specific RNA. Based on the obtained results, WNV was circulating in the DDBR during 2016

The effect of hybrid COBB 500 broiler parents' age and egg storage period length on chicken incubation efficiency

U cilju utvrđivanja produktivnih i reproduktivnih osobina brojlerskih roditelja hibrida Cobb 500 sprovedena su istraživanja na jednom matičnom jatu koje je gajeno od 23. do 60. nedelje starosti (38 nedelja). U toku istraživanja praćeni su sledeći proizvodno – reproduktivni parametri: intenzitet nosivosti jaja različitih kategorija, mortalitet i vitalnost roditeljskih parova, utrošak hrane po grlu i proizvedenom jajetu. Posebna pažnja data je reproduktivnim osobinama, tj. proizvodnji jednodnevnih brojlerskih pilića, kao finalnog proizvoda. Osnovni cilj rada bio je utvrđivanje uticaja pojedinih paragenetskih faktora na rezultate inkubacije, u prvom redu, starosti brojlerskih roditelja (SR) i perioda skladištenja jaja, odnosno starosti jaja (SJ). U tri faze proizvodnog ciklusa gajenja, odnosno različite starosti brojlerskih roditelja (SR25, SR41 i SR58) i kod jaja skladištenih do 7 i preko 7 dana (SJ7) utvrđeni su: masa jaja različitih kategorija, oplođenost jaja, izvodljivost pilića, embrionalni mortalitet u toku inkubacionog perioda (rani, srednji i kasni), masa jednodnevnih pilića, relativni udeo pileta u masi jajeta, kao i fenotipska korelaciona (rp) povezanost između većine praćenih reproduktivnih pokazatelja. Pored osnovnih produktivnih i reproduktivnih parametara utvrđivan je uticaj starosti brojlerskih roditelja po fazama proizvodnog ciklusa i dužine skladištenja, odnosno starosti jaja na embrionalni razvoj pilića i rezultate inkubacije. Posmatrano po fazama gajenja, brojlerski roditelji su najbolje proizvodne, odnosno reproduktivne vrednosti pokazali sredinom proizvodnog ciklusa (SR41), u odnosu na početnu (SR25) i završnu fazu (SR58) produkcije jaja za nasad. U tom periodu po useljenoj nosilji proizvedeno je 5,08 jaja, 4,74 oplođenih jaja, 4,40 jednodnevnih pilića, dok je prosečan dnevni utrošak hrane po useljenom grlu iznosio 181,00 g. Prosečna masa jaja skladištenih do 7 dana je bila u optimalnim granicama, i iznosila je 63,11 g., oplođenost jaja iznosila je 97,43%, leženost pilića 87,62% (od inkubiranih jaja), odnosno 89,93% (od oplođenih jaja). Masa jednodnevnih pilića bila je na zadovoljavajućem nivou (44,02 g) i relativni udeo pileta u masi jajeta iznosio je 69,73%. Pored toga, starost brojlerskih roditelja je uticala na povećanje mase jaja (P<0,001) i izleženih pilića (P<0,001), dok se procenat pileta u masi jajeta smanjivao, a period skladištenja jaja, kod sve tri faze proizvodnog ciklusa, negativno je uticao na procenat pileta, tj. sa produžavanjem perioda skladištenja jaja, relativni udeo pileta u masi jajeta se smanjivao, posebno u početnoj (SR25) i završnoj fazi (SR58) proizvodnog ciklusa (P<0,001).The research was conducted on one breeding flock of hybrid Cobb 500 broiler parents bred in the interval between 23rd and 60th week of age with the objective of determining their production and reproduction characteristics. The following production – reproduction parameters were inspected: carrying capacity of different category eggs, mortality and vitality of parents couples, the consumption of food per head and per egg produced. Special attention was paid on reproduction characteristics, i.e. on the production of diurnal broiler chicken as a final product. The main objective of this doctoral dissertation was to determine the effect of certain paragenetic factors, primarily broiler parents’ age (PA) and storage eggs period i.e. eggs age (EA), on incubation results. In the course of the three stages of production breeding cycle, i.e. regarding different age of broiler parents (PA25, PA41 and PA58) and regarding eggs stored up to seven and over seven days (EA7), the following was substantiated: different category eggs mass, the degree of fertilization of eggs, chicken feasibility, embryo mortality during incubation period (early, middle, late), diurnal chicken mass, the relative proportion of chicken in the egg mass, and phenotype correlative (rp) relatedness among the majority of observed reproduction indicators. Beside basic production and reproduction parameters, the effect of broiler parents’ age during the stages of the production cycle and storage period length i.e. eggs age on chicken embryo development and incubation results was substantiated. Observing each breeding stage, broiler parents showed the best production and reproduction values in the middle of the production cycle. Namely, compared to the initial (PA25) and final (PA58) stage of clutch eggs production, broiler parents had the best production and reproduction characteristics in the middle of the production cycle (PA41). In this period, 5.08 eggs, 4.74 fertilized eggs and 4.40 diurnal chickens were produced per occupied layer hen, whereas the average daily consumption of food was 181.00 g per occupied head. The average mass of eggs stored up to seven days was 63.11 g, which falls within the optimal boundaries, the fertilization of eggs was 97.43%, chicken hatching was 87.62% among incubated eggs and 89.93% among fertilized eggs. Diurnal chicken mass was on a satisfying level (44.02 g) and a relative proportion of chicken in the egg mass was 69.73%. Besides, broiler parents’ age caused the egg mass increase (P<0.001) and hatched chicken increase (P<0.001), whereas the percentage of chicken in the egg mass decreased. Egg storage period, in each of the three stages of the production cycle, negatively affected the chicken percentage: with the prolongation of egg storage period, the relative proportion of chicken in egg mass was reduced, especially in the initial (PA25) and final (PA58) stage of production cycle (P<0.001)

Hysteresis and the nairu: The case of countries in transition

© University of Economics, Prague. The paper examines the hysteresis hypothesis in unemployment in the case of eight selected countries in transition, using the Kalman filter and testing whether the NAIRU time series are stationary. The empirical results show that the hysteresis effect is confirmed for the majority of the countries. Testing the influence of the inflation growth rate on the decline in the NAIRU and vice versa, performed using the panel regression with fixed effect, confirmed that the increase in inflation leads to decline in the NAIRU. The conclusion also suggests the existence of the impact of actual unemployment rate on the NAIRU, which may be affected by the change in aggregate demand

An Engineered Nonribosomal Peptide Synthetase Shows Opposite Amino Acid Loading and Condensation Specificity

Engineering of nonribosomal peptide synthetases (NRPS) has faced numerous obstacles despite being an attractive path towards novel bioactive molecules. Specificity filters in the nonribosomal peptide assembly line determine engineering success, but the relative contribution of adenylation (A-) and condensation (C-)domains is under debate. In the engineered, bimodular NRPS sdV-GrsA/GrsB1, the first module is a subdomain-swapped chimera showing substrate promiscuity. On sdV-GrsA and evolved mutants, we have employed kinetic modelling to investigate product specificity under substrate competition. Our model contains one step, in which the A-domain acylates the thiolation (T-)domain, and one condensation step deacylating the T-domain. The simplified model agrees well with experimentally determined acylation preferences and shows that the condensation specificity is mismatched with the engineered acylation specificity. Our model predicts changing product specificity in the course of the reaction due to dynamic T-domain loading, and that A-domain overrules C-domain specificity when T-domain loading reaches a steady-state. Thus, we have established a tool for investigating poorly accessible C-domain specificity through nonlinear kinetic modeling and gained critical insights how the interplay of A- and C-domains determines the product specificity of NRPSs. </div

Overcoming Low Germination and Low Quality of Flax Seeds (<i>Linum usitatissimum</i> L.) in Unfavorable Storage Using Static Magnetic Fields

Flax seeds stored in unfavorable conditions were exposed to static magnetic fields (SMFs) of 50–350 mT for 20–120 min to overcome low germination and quality. Seed germination increased slightly with increasing strength of SMF and duration of treatment. Seed germination from 89% to 100% was achieved in SMF treatments of 150 mT (120 min), 200 mT (80–120 mT), 250 mT (60–120 min), 300 mT (40–120 min), and 350 mT (40–120 min). In these treatments, germination was 2.78- to 3.12-fold higher than in the control after 10 days. Treatments with 350 mT for 100 and 120 min showed the best results in germination (100%), as well as a 26.81-fold increase in vigor I, 28.69-fold increase in vigor II, 1-fold increase in chlorophyll a, 0.84-fold in chlorophyll b, 0.46-fold increase in carotenoid content, and 2.63-fold increase in catalase activity compared to the control after 10 days. Also, SMF treatment of 350 mT (20–120 min) reduced cell leakage and electrical conductivity by 1-fold compared to the control. SMF is a healthy, biologically safe, and environmentally friendly treatment and can be a tool for overcoming problems of low germination and quality of seeds stored under unfavorable conditions