Hatching duration and incubation temperature on the quality of chicks, its performance and meat quality

Author(s)

João Batista Matos Junior

• Document type: Doctoral Thesis
• Press: Jaboticabal. 2016-03-29.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2016-02-17
• Advisor: Isabel Cristina Boleli

Abstract

The present study investigated if the duration of emergence (time period between external pipping and the actual hatching (DEP-H) associated to incubation temperature (37.5 and 39°C) during fetal development phase, influences: (i) the eggshell temperature and thickness and the weight loss of eggs, quality and blood characteristics of broiler chicks at hatching, (ii) thermal preference and response to heat stress throughout grow out phase, and (iii) and performance and quality of meat, in Chapters 2, 3, 4 and 5, respectively. Chapter 2, fertile eggs from broilers hans (Cobb® 500) were used in a 2x2 experiment (time between external piping and actual hactching: short and long, incubation temperature: 39°C and 37.5, from the 13th day of incubation). High temperature decreased the duration of incubation, but did not alter the hatching rate and the quality of the chicks. The values of PvCO2, PvO2, TvCO2, SvO2, pH, BEecf, HCO3-, Na+, K+, glucose, total cholesterol, urea, uric acid, triglycerides, and total protein in blood were not altered by incubation at 39°C, but the Hct, the HCM and the concentration of iCa were higher in hatching chicks to 39°C than at 37.5°C. The data show that broiler respond to the high incubation temperature and the length of the hatching period with hematological adjustments that increase their potential for gas exchange, enabling the maintenance of hatching rate and its quality. In chapter 3 we investigated whether the time between external piping and actual hactching (DEP-H, short- and long-Cap 2) influences the performance, yield and meat quality of broilers. The duration of the hatching period did not influence weight gain, feed intake and feed conversion of 1-42 days of age, body weight and carcass yield and slaughtering age, except for the of the back yield which was higher in broilers from shorter than long period of hatching. As regards the quality of the meat, DEP-H did not influence the cooking loss, shear force, pH, water capacity loss, color indices (L*, a* and b*) and the size of muscle breast fibers of broilers. There was no effect of the duration of the hatching period on the shear strength, pH, color and size indices of oxidative muscle fibers slow and glycolytic and fast over-thigh contraction. However, broilers with long DEP-H showed higher cooking loss, water loss of capacity and size of oxidative-glycolytic fast twitch fiber. The results show that hatching period influences with the quality of the meat on the thigh-, and short DEP-H broilers present meat more tender and juicy over-thigh broilers with long DEP-H. In Chapter 4, the experimental design was similar to the Chapter 2. Chicks from eggs incubated at 37.5°C and short DEP-H preferred lower temperature at all ages analyzed during the creation (1, 7, 14, 21, 28, 35 days), whereas the chicks from incubation at 39°C and long DEP-H preferred DEP-H higher temperatures from 21 days of age. Regardless of DEP-H and incubation temperature, broilers showed increased frequency of breathing movements when exposed to high ambient temperature (2, 8, 15, 22, 29 and 36 days of age), able to maintain their body temperature in all ages. These results show that DEP-H associated or not with high incubation temperature influences the thermal preference of broilers during the rearing period, but not their response to heat. In Chapter 5 examined whether the length of time time period between external pipping and the actual hatching (DEP-H, short-and long-Cap 2), and the rearing of temperature (recommended for lineage and preferred by birds in preference in the test in Cap 4) interfere performance, yield and quality of broiler meat. Broilers with short and long DEP-H reared at the recommended temperature for the strain showed similar body weight, weight gain and feed conversion at 42 days of age; however, broilers with long DEP-H reared at the recommended temperature and preferred temperature consumed less feed than broilers with short DEP-H which resulted in a lower weight gain and body weight at 42 days old. The best performance of the broilerss with short DEP-H in preferred temperature resulted in higher breast weight than in broilers with long DEP-H also raised in the thermal preference. The cooking loss, shear force, pH, L* indexes a* and b* and muscle fiber size of the chicken breast meat were not influenced by DEP-H and CT, however, the water retention capacity was lower in broiles with short DEP-H raised at the recommended temperature for the lineage than in broilers with long DEP-H reared in the same thermal condition and that in chickens with short DEP-H reared in temperature preference. As regards the quality of the meat of the thigh of broiler with the same DEP-H reared at different temperatures, there has been increased stiffness and decreased tenderness of the meat of broilers with short DEP-H when these are raised in preferred temperature.The study data show that length of hatching period influences with the performance, carcass yield and cuts, and breast meat quality and on-thigh of broilers. (AU)

• FAPESP's process: 12/14428-0 - EFFECT OF DURATION OF HATCHING PERIOD ON QUALITY CHICKS ON THE QUALITY AND PERFORMANCE AHEAD OR NOT HEAT STRESS
• Grantee: João Batista Matos Junior
• Support Opportunities: Scholarships in Brazil - Doctorate