Resumen

YUNO, M et al. Características físicas del huevo incubable y pollitos nacidos de reproductores pesados cobb 500 en incubadoras con diferente humedad relativa. RIA. Rev. investig. agropecu. [online]. 2013, vol.39, n.3, pp.290-296. ISSN 1669-2314.

The physical characteristics of the incubatable egg (weigh -PH-, eggshell quality -C- and humidity loss -H-) and born chicks (weight -PP- and hatchability -N-) from Cobb 500 heavy breeders within 28 and 56 weeks of age, were evaluated in three setters of different relative humidity (HR) and compared with the standard values for the genetic line. The PH 56,7-73,2 g) was 0.9 and 6.5% higher (p<0.05) than the standard (56,2-68,4 g) (in all weeks of age, possibly linked to the management of the lot, which was out-of-season and in open sheds; consequently, the PP (49±3 g) and the PP/PH ratio (71±0.01%) were higher (p<0.05) than the standard (34-46 g and 66-68%, respectively). The PH and the PP had a positive quadratic relationship (p<0.05) in all weeks of age. The C value for all eggs analysed was 1082±4, indicating a good eggshell and albumin quality, although a negative linear relationship (p<0.05) between C and the age of the breeder was noticed. The H was 10.7±0.8%, 10.5±1% and 10.4±0.8% in the setter of 51.3%, 56.5% and 62.1% HR, respectively, lower (p<0.05) than the standard (11-12%), and there were significant differences (p<0.05) only between the setter of 51.3% y 62.1% of HR. In the three setters, the age of the breeder had a positive linear relationship (p<0.05) with H but a negative linear relationship (p<0.05) with N. It was noticed that H had a linear negative relationship (p<0.05) with C only in the setters of 51.3% and 56.5% HR, indicating that C could be less relevant in setters of higher HR. The mean N value throughout the period was similar between the setters and were 83.3±4%, 83.2±4% y 83.1±4% for 51.3%, 56.5% and 62.1% HR, respectively. The negative linear relationship (p <0.05) between N and age of the breeders in the three incubators can be linked to physiological changes in the internal composition of eggs (higher pH, lower C and increased embryonic mortality). The dehydration of eggs was greater (p <0.05) in 51.3% setter than 62.1%, however, and although both the H was lower than the standard values , the N were similar and within normal values.

Palabras clave : Cobb 500 breeders; Egg humidity loss; Hatchability; Setters.

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