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 cm 2 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. -egg layers, strain, ISA Brown, Hisex Brown, Moravia BSL, age, yolk, albumen, shell quality, correlation
Brown
ABSTRACT:In an experiment with three strains of Dominant genotype the effect of oviposition on egg quality characteristics was investigated. Laying hens of the Blue strain (group 1), Plymouth Rock (group 2) and their F1 cross (group 3) from 20 to 64 weeks of age were housed on litter (9 birds per m 2 ). The collection time was at 6.00, 10.00 and 14.00 h. Eggs were gathered in a 28-day interval, every two days all produced eggs (720 eggs in total). The time of oviposition was influenced by genotype. The highest number of eggs was collected in the Plymouth Rock strain at 6.00 (53.5%) and the lowest in the Blue strain at 14.00 (11.1%). There were interactions between the time of oviposition and genotype in egg weight. Eggs laid in the morning at 6.00 were significantly heavier (60.5 g, 64.9 g and 62.1 g) in comparison with eggs laid in the afternoon (59.3 g, 62.4 g and 62.7 g). The heaviest eggs were produced by the Plymouth Rock strain. Significant interactions were observed in eggshell weight when the heaviest eggshell was in afternoon eggs (5.6 g, 5.8 and 5.9 g) and F1 genotype. The egg shape index was also affected by the genotype and time of oviposition. Among the albumen quality characteristics only Haugh Units were influenced by genotype and significantly higher numbers were determined in the Plymouth Rock strain (85.0, 85.3 and 84.7). The genotype significantly affected also the yolk index which was the highest in F1 genotype (45.4%, 45.4% and 44.5%).
This study examined the effects of supplementation of dietary sodium selenite and sodium enriched alga Chlorella on growth performance, selenium concentration in breast meat and excreta, activity of glutathione peroxidase in meat, and oxidative stability of meat in broilers. Sexed broiler cockerels Ross 308 were allotted to 3 dietary treatments, each comprising 100 chickens. The basal diet was supplemented with 0 (control) or 0.3 mg/kg Se from sodium selenite (SS) or Se-Chlorella (SCH). Dietary supplementation with SCH increased (P < 0.05) body weight. The breast muscle Se concentration was increased (P < 0.05) by SCH (0.70 mg/kg DM; 0.36 mg/kg DM in control) supplementation, but not (P > 0.05) by SS (0.49 mg/kg DM) supplementation. The concentration of Se in excreta was highest in the SS group. The activity of GSH-Px in breast meat was significant P < 0.05) in all treatments (0.16 U/g in control, 0.30 U/g in SS and 0.23 U/g in SCH group). The inclusion of SCH in the diet enhanced the oxidative stability of meat expressed as reduced malondialdehyde (MDA) values in breast meat after 0; 3 and 5 days storage in refrigerator at 3 to 5°C.
The study examined the effect of dietary supplements of sodium selenite (SS), selenium-enriched yeast (Sel-Plex®, SP) and selenium-enriched alga Chlorella (SCH) on growth traits, carcass analysis, selenium content in breast meat, glutathione peroxidase (GSH-Px) activity in breast and thigh meat and liver of chickens. The experiment was realized with seven hundred thirty-five cockerels Ross 308 randomly divided into 7 dietary treatments with 3 replications in each treatment. Chickens were fed a diet supplemented with 0 (control), 0.15 or 0.30 mg of selenium/kg in the form of sodium selenite (SS), Sel-Plex® (SP) and selenium-enriched alga Chlorella (SCH). Selenium addition influenced body weight at 21 (P ≤ 0.001) and 35 (P ≤ 0.05) days of age. Significantly higher body weight at 35 days of age was determined in chickens receiving 0.15 mg of selenium from SP (2 122 g) and 0.3 mg of selenium from SCH (2 116 g) contrary to dietary treatment with a lower level of selenium from SCH (2 010 g) per kg of feed. The selenium content in breast muscle was increased (P ≤ 0.001) by both the lower and higher selenium concentration in the form of SP (0.6 and 0.85 mg/kg dry matter) and SCH (0.6 and 0.82 mg/kg dry matter) in comparison with the control (0.31 mg/kg dry matter). A significant increase (P ≤ 0.001) was ascertained even in SS treatments, but no significant differences were found between both levels. The selenium source and level, including SS, significantly (P ≤ 0.001) influenced the GSH-Px activity in breast and thigh meat.
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