Research Note Effects of preincubation and higher initiating incubation temperature of long-term stored hatching eggs on hatchability and day-old chick and yolk sac weight

We studied the effect of increased initial incubation temperature and repeated preincubation of 35-d stored eggs from 46 week old Ross 308 parental stock on the hatchability and day-old chick and yolk sac weight. Two different temperatures were applied during the first 36h and they were combined with four preincubation treatments during storage. One half of the hatching eggs (2400) were incubated for the first 36h at an incubation temperature of 38.3 oC, and the second half were incubated at a higher temperature of 39.2 oC. Four different preincubations were applied; none, once at the 7th day of hatching egg storage, twice at the 7th and 12th days of storage and three times at the 7th, 12th and 19th days of storage. Both preincubation and increased temperature had negative effects on hatchability (P<0.001). The interaction between these two factors was also significant (P<0.05). These two factors also negatively affected early and late embryonic mortality (P<0.001). However, middle embryonic mortality was not influenced. Live weight, weight of residual yolk sac and yolk sac proportion were not affected by repeated preincubation nor by increased temperature over the first 36h of incubation (P>0.05). A higher initial temperature decreased chick yolk free body mass (P<0.05).Although neither increased initial temperature in the setter nor repeated preincubation affected one day old chick weights, these treatments were not suitable for long-term stored eggs because of decreased hatchability and impairment of one day chick quality expressed as yolk free body mass.O

Faktory ovlivňující kvalitu krůtího masa

The objective of this thesis was to present the factors affecting quality of turkey meat. In the first section, the production of turkey meat in the world and especially in Europe are described. Further it gives information about world trade, import and export of turkey meat in the Czech Republic. Besides these next part of the thesis focuses on the history and current situation in turkey breeding in the Czech Republic. Then this thesis deals with breeding of turkeys in the world and with the main objectives, author describes the most commonly used hybrid types of turkeys and fattening technologies. It also discusses the quality of turkey meat, the nutritional value and the sensory properties and the factors that affect the quality indicators. Interest in the production and consumption of turkey meat is affected by its slaughtering, nutritional and sensory quality. The main part of the thesis is devoted to the description of factors influencing the quality characteristics of turkey meat. Carcass yield and the yield of valuable parts (meat from the breasts and thighs) are the main indicators of the yield of turkey meat, which are influenced by the age and sex of the animal, breeding, and slaughter processing technology. The nutritional quality of the meat is assessed based on its chemical composition, its nitrogen and fat contents. The nutritional quality is influenced by the genetics, nutrition, sex and age of the animal. The sensory and physical properties of the meat are also affected by the handling with the animals between the end of fattening and slaughtering as well as by health aspects during their life

Vliv skladování násadových vajec na parametry užitkovosti brojlerových kuřat

This thesis deals with the effect of eighteen-day storage of hatching eggs of broiler chickens on the quality of day-old chicks and their performance parameters. The experiment was performed on 562 Ross 308 hybrid chickens from hatch to day 35 of age. Control group chicks were hatched from eggs set in to incubator after four days of lay, while the test group eggs were stored for 18 days prior to incubation. There was no statistically significant (P˃0,05) difference between the groups in the average day-old chicks weight. However, at days 10, 17, 24, 31, and 35, the average weight of experimental group was statistically significant (P˂0,05) below the weight of the control group. The chickens of the experimental group showed statistically significant (P˂0,05) higher trypsin activity (2703,15 U/ml) compared to the control group chickens (2125,60 U/ml). The difference in the average weight of the pancreas or pancreas in proportion of live weight between the groups was not statistically significant. There was no difference in the mean villus length between the groups studied. However, the mean depth of intestinal crypts was statistically significantly (P˂0.05) higher (106,78 µm) in the control group than in the experimental group (89,64 µm). A statistically significant (P˂0,05) difference was also found in the ratio between villi length and crypt depth, where the ratio was 5,07 in the experimental group, while in the control group it was lower (4,60). Long-term storage of hatching eggs has had a negative impact on the growth of broiler chickens