Jak genotyp ovlivňuje kvalitu vajec ve druhé polovině snáškového cyklu?

The objective of this study was to determine and compare egg quality from two genotypes of brown egg-laying hens in the second half of laying cycle (from 46 to 74 weeks of age). Commercial hybrids Hisex Brown and Lohmann Brown Classic were used in this study. Both genotypes were kept in enriched cages. 1920 eggs were evaluated. The significant effect of genotype was found in all evaluated traits except for the eggshell proportion and reflectivity. Results show that eggs from Lohmann Brown Classic hens had a superior quality in majority of the evaluated traits. Higher values were observed in main egg quality traits, such as egg weight (by 1.45 g, P≤0.0001), eggshell strength (by 2.48 N*cm-2, P≤0.0005) and Haugh units (by 3.27, P≤0.0001). The significant effect of age was determined in all selected egg quality traits. The egg weight increased with the age, meanwhile other traits such as egg shape, albumen and yolk index, Haugh units and eggshell strength decreased. The trend of the rest of evaluated traits was ambiguous. Furthermore, the interactions between genotype and age were determined. Regarding the extension of laying cycle, further research is required, because the egg quality rapidly decreases with the age.Cílem této studie bylo stanovit a porovnat vybrané fyzikální vlastnosti vajec od dvou genotypů hnědovaječných nosnic ve druhé polovině snáškového cyklu (od 46 do 74 týdnů věku). V této studii byli použiti komerční hybridi Hisex Brown a Lohmann Brown Classic. Oba genotypy byly ustájeny v obohacených klecích. Bylo hodnoceno 1920 vajec. Signifikantní vliv genotypu byl zjištěn ve všech hodnocených parametrech kromě podílu skořápky a reflektivity skořápky. Výsledky ukazují, že vejce od slepic Lohmann Brown Classic měla vyšší kvalitu ve většině hodnocených parametrů. Lepší hodnoty byly zjištěny u hlavních parametrů technologické hodnoty vajec, jako jsou hmotnost vejce (o 1,45 g, P≤0,0001), pevnost skořápky (o 2,48 N*cm-2, P≤0,0005) a Haughovy jednotky (o 3,27, P≤0,0001). Signifikantní vliv věku byl stanoven u všech vybraných kvalitativních parametrů vejce. Hmotnost vajec se s věkem zvyšovala, zatímco se snižovaly hodnoty ostatních parametrů, jako jsou index tvaru vejce, bílku a žloutku, Haughovy jednotky a pevnost skořápky. Trend u ostatních hodnocených parametrů byl kolísavý. Dále byly stanoveny interakce mezi genotypem a věkem. Z hlediska prodloužení snáškového cyklu je nutný další výzkum, protože kvalita vajec se s věkem rapidně snižuje

Učinak dobi japanskih prepelica na određena obilježja kakvoće jaja i njihovi međusobni odnosi.

The effect of age on the egg quality traits of Japanese quails (Coturnix coturnix japonica) were investigated. One hundred female quails were used in the study. The quails were placed in wire cages (3 females per cage) and fed a mixture with 11.2 MJ ME and 19.7% of crude protein throughout the experiment. Feed and water were given ad libitum. Eggs were collected on 2 consecutive days during the 4-week period when the quails were from 9 to 49 weeks of age. A total of 2,060 eggs were examined. Egg quality traits were significantly affected by the age of the quails, with the exception of egg shape index and yolk colour. A rapid increase in the egg weight was found at the beginning of laying, the highest weight (13.02 g) was found in the 25th week of age, with a subsequent gradual decrease in egg weight until the end of the laying period at 49 weeks of age. Despite frequent fluctuations, the albumen index, albumen weight, albumen proportion, Haugh units score, eggshell weight and eggshell strength decreased with increasing age, but the yolk proportion, eggshell proportion increased with the quails’ age. The egg weight was positively correlated (P≤0.001) with yolk weight, albumen weight and eggshell weight (0.70, 0.90 and 0.58, respectively). The Haugh unit score was positively correlated with the albumen index (0.94; P≤0.001).Istražen je učinak dobi japanskih prepelica (Coturnix coturnix japonica) na određena obilježja kvalitete njihovih jaja. Istraživanje je provedeno na sto prepelica. Prepelice su tijekom pokusa bile smještene u žičane kaveze (tri ženke po kavezu) i hranjene mješavinom s 11,2 MJ ME i 19,7% sirovih proteina. Hranu i vodu dobivale su ad libitum. Jaja su bila sakupljana dva uzastopna dana tijekom četiri tjedna kad su prepelice bile u dobi od 9 to 49 tjedana. Ukupno je bilo pretraženo 2060 jaja. Dob prepelica značajno je utjecala na pokazatelje kvalitete jaja osim na oblik i boju žumanjka. Brzo povećanje mase jaja ustanovljeno je u početnoj fazi nesenja. Najveća masa (13,02 g) bila je dostignuta u dobi od 25 tjedana, a potom se postupno smanjivala sve do kraja razdoblja leženja odnosno do dobi od 49 tjedana. Unatoč čestim kolebanjima, indeks bjelanjka, masa bjelanjka, proporcija bjelanjka, vrijednosti Haughove jedinice, masa ljuske i čvrstoća ljuske smanjivali su se s povećanjem dobi, dok su se proporcija žumanjka i proporcija ljuske povećavali s dobi prepelica. Masa jajeta bila je u pozitivnoj korelaciji (P≤0,001) s masom žumanjka (0,70), masom bjelanjka (0,90), i masom ljuske (0,58). Omjer Haughove jedinice bio je u pozitivnoj korelaciji s indeksom bjelanjka (0,94; P≤0,001)

Effects of Genotype, Age and Their Interaction on Egg Quality in Brown-Egg Laying Hens

The experiment compared the effects of strain and age on egg quality characteristics in ISA Brown, Hisex Brown and Moravia BSL brown-egg laying hens. One hundred and eight ISA Brown hens, forty-five Hisex Brown and forty-five Moravia BSL 20 to 60 weeks old were housed in conventional cages (550 cm2 per hen). Feed and water were available ad libitum. Eggs were sampled at 21-day intervals, every collecting week 150 eggs per genotype in three age periods, from 20 to 26 weeks, 37 to 43 weeks and 54 to 60 weeks of age. A total of 4,050 eggs were examined. Egg quality characteristics were affected by genotype and age. Egg weight, yolk weight and percentage, Haugh Units increased with the hens’ age in all genotypes, but albumen and eggshell percentage decreased, eggshell thickness and strength improved with age. The highest egg weight (65.3 g) and yolk quality (yolk index 45.1%) were found in Moravia BSL at the end of the experiment. In contrast, the best albumen quality (albumen percentage 60.0) values were in Hisex Brown and the eggshell quality measurements (eggshell thickness 0.38 mm) were higher in ISA Brown

Effect of genotype and housing system on the concentration of cholesterol in egg yolk

Cílem práce bylo posoudit koncentraci cholesterolu ve vaječném žloutku u plemen Česká slepice a Oravka chovaných ve dvou odlišných systémech chovu (klece a podestýlka). Během pokusného období byla také sledována snáška vajec, intenzita snášky, spotřeba krmné směsi. Vejce pro laboratorní analýzu (pro odběr žloutků pro stanovení cholesterolu) byla sbírána ve 28 denních intervalech, ve 34, 38, 42, 46 a 50 týdnech věku nosnic. Stanovení cholesterolu bylo provedeno pomocí vysokorozlišovací kapilární plynové chromatografie (HRGC). Ze sledovaných parametrů užitkovosti byla plemenem, systémem ustájení i jejich vzájemnou interakcí průkazně ovlivněna pouze denní spotřeba krmné směsi. Koncentrace cholesterolu byla signifikantně ovlivněna genotypem nosnic i systémem ustájení. Nejvyšší průměrná koncentrace cholesterolu ve vaječném žloutku byla v chovu na podestýlce u plemene Oravka (11,64 mg/g) i Česká slepice (10,84 mg/g) v porovnání s klecovým systémem ustájení. Současně byl také prokázán vliv věku nosnic i jeho vzájemná interakce se systémem ustájení. Nejvyšší koncentrace byla ve 34. týdnu věku nosnic ustájených na podestýlce. Naopak nejnižší koncentrace byla zjištěna ve 42. týdnu věku od nosnic z klecí. Ostatní sledované parametry nebyly průkazné. Z výsledků sledování vyplývá, že výběrem vhodného genotypu a systému ustájení lze ovlivnit koncentraci cholesterolu ve vaječném žloutku.The objective of the study was to assess the concentration of egg yolk cholesterol in Czech Hen and Oravka breeds kept in two different breeding systems (cages and litter). Egg-yield, hen day egg production and feed mixtures consumption were observed during the experimental period. The eggs for laboratory analysis were collected during 4-week periods, at 34, 38, 42, 46 and 50 weeks of age of the laying hens. Sample extracts were analyzed by gas chromatography employing mass selective detector. Only daily consumption of feed mixtures was significantly affected by genotype, housing systems and their interaction. The cholesterol concentration was significantly affected by genotype and housing system of laying hens. The highest average concentration of cholesterol in egg yolk was determined on litter (Oravka 11.64 mg/g and Czech Hen 10.84 mg/g) compared to cages. Simultaneously, the influences of age of laying hens and its interaction with the housing system were also demonstrated. The highest concentration of cholesterol was measured at 34 weeks of age of hens bred on litter. Conversely, the lowest concentration was found at 42 weeks of age of hens housed in cages. Other parameters were inconclusive. The results showed that the selection of a suitable genotype and housing system can significantly affect the concentration of cholesterol in egg yolk

Performance and eggs quality of hens of genetic resources of the Czech Republic and Slovakia

The aim of this study was to assess the performance and technological values of eggs of Czech Hen and Oravka breeds housed on litter. The assumption was that the genotype of hens affects their performance, egg weight, and parameters of yolk, albumen and eggshell quality. A total of 30 pullets of Czech Hen breed and 30 pullets of Oravka breed in the age of 17 weeks were included in to the experiment. Environmental conditions corresponded to the standard requirements for laying hens in observed type of housing system. Hen day egg production, egg yield, daily feed consumption per hen, feed consumption per egg and egg weight, egg shape index, proportion and index of yolk and albumen,yolk colour and Haugh units score were monitored in the experiment. From the parameters of eggshell, proportion, thickness, strength and colour of eggshell were observed. Performance parameters of laying hens weren\u27t affected by the genotype of hens. Czech Hen breed showed insignificantly the higher value in all indicators. The significantly (P ≤ 0.01 and P ≤ 0.001) better values of eggshell quality parameters were detected in Czech Hen breed. We found out that Czech Hen breed had also statistically significantly lighter colour of eggshell. There were no significant interbreed differences in egg weight, proportion of yolk and albumen. The egg shape index was significantly higher in Oravka. Index of yolk and albumen was also significantly (P ≤ 0.001) higher in Oravka. Haugh units score, that reflect the quality of the eggs, were found significantly (P ≤ 0.001)higher in Oravka too. On the other hand, yolk colour was detected significantly (P ≤ 0.001) darker for the Czech Hen

Utjecaj rednog broja laktacije na omjer važnih zdravih masnih kiselina u sirovom mlijeku krava holstein pasmine

The objective of this study was to determine and evaluate the effect of parity on the fatty acids groups’ proportion in Holstein cows’ milk during the first phase of lactations, with an emphasis on its potential importance for consumer health. A total of 25 Holstein cows, 9 primiparous, 9 in the 2nd, and 7 in the 3rd and subsequent parity, were observed and sampled at 7-day intervals through the first 17 weeks of lactation. The percentage proportion of saturated (hypercholesterolemic and volatile as its components) and unsaturated (monounsaturated and polyunsaturated as its components) fatty acids in the samples of milk fat (n=425) was determined. The effects of parity and negative energy balance, as well as regression, on the lactation week and the fat to protein ratio were evaluated using SAS 9.3. A significantly (P<0.01) lower proportion of unhealthy hypercholesterolemic fatty acids was detected in primiparous cows (-2.67 %) and those in the 3rd and subsequent lactation (-2.94 %) compared to the 2nd lactation, as well as a simultaneously higher proportion of healthy unsaturated fatty acids (+2.07, respectively +3.08 %). The determined relationships corresponded to organism stress evoked by the initiation of milk production and its maintenance in higher parities. Therefore, the generally required prolongation of dairy cows’ longevity can influence on the quality of raw milk, especially considering composition of fatty acids.Cilj ovog istraživanja bio je utvrditi i procijeniti utjecaj rednog broja laktacije na udio pojedinih skupina masnih kiselina, u mlijeku holstein krava tijekom prve faze laktacije, s naglaskom na njihovu potencijalnu važnost za zdravlje potrošača. Ukupno 25 holstein krava, devet prvotelkinja, devet u drugoj, i sedam u trećoj i naknadnim laktacijama, promatrane su i uzorkovane u sedmodnevnim intervalima tijekom prvih 17 tjedana laktacije. Utvrđivan je udio zasićenih (unutar te skupine hiperkolesterolemičnih i hlapivih masnih kiselina) te nezasićenih (unutar te skupine mononezasićenih i polinezasićenih) masnih kiselina u uzorcima mliječne masti (n=425). Utjecaj rednog broja laktacije i negativne energetske bilance, kao i regresija, na tjedne laktacije i omjer masti i proteina procijenjeni su pomoću SAS 9.3. Značajno (P<0,01) manji udio po zdravlje nepovoljnih hiperkolesterolemičnih masnih kiselina utvrđen je u prvotelkinja (-2,67 %) i onih u 3. i naknadnim laktacijama (-2,94 %) u odnosu na krave u drugoj laktaciji, kao i istodobno veći udio po zdravlje povoljnih nezasićenih masnih kiselina (2,07 %, odnosno 3,08 %). Utvrđena veza objašnjava se stresom organizma prouzrokovanim početkom proizvodnje mlijeka i održavanjem te proizvodnje tijekom kasnijih laktacija. Dakle, općenito dulji životni vijek mliječnih krava može utjecati na kvalitetu sirovog mlijeka, osobito s obzirom na sastav masnih kiselina

Dietary Inclusion of Crickets (Acheta domesticus) and Yellow Mealworm Meal (Tenebrio molitor) in Comparison with Soybean Meal: Effect on the Growth, Total Tract Apparent Digestibility, and Nitrogen Balance of Fattening Rabbits

Three diets were formulated, i.e., soybean meal (SM diet), adult Acheta domesticus (AD diet), and Tenebrio molitor larvae (TM diet), as the main crude protein (CP) sources. A total of 45 rabbits (Hyplus, weaned at 32 days of age) were divided into three groups (15 per treatment) and fed one of the three diets for 42 days. A higher daily weight gain (p = 0.042), as well as daily feed intake (p = 0.022), was observed in rabbits fed the AD and TM diets than in rabbits fed the SM diet within 21 days after weaning. The coefficients of total tract apparent digestibility (CTTAD) of gross energy were higher (p = 0.001) in rabbits fed the SM diet than in rabbits fed the other diets. The CTTAD of CP (p = 0.040) and starch (p = 0.041) was higher in rabbits fed the SM diet compared to those fed the AD diet. There were non-significantly higher losses of nitrogen in the urine (an average by 0.227 g/day; p = 0.094) in rabbits fed the TM diet than in rabbits fed the other diets. It can be concluded that the growth of rabbits and nitrogen output were not detrimentally affected by the insect meal (AD or TM) used in this study