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The influence of inducing early reproductive activity in young hens and roosters of egg-laying type breed

Domenii publicaţii > Biologie + Tipuri publicaţii > Articol în revistã ştiinţificã

Autori: Miclea V., Daniela Ladosi., I. Ladosi, M. Zahan

Editorial: Journal of Central European Agriculture, 3 (4), p.353-362, 2002.

Rezumat:

Un efectiv de 60 puicute si 40 cocosei din rasa Rhode Island a fost structurat in loturile L1, L2, L3. Pasarile lotului L1 au fost trecute la varsta de 16 saptamani de la 8 la 14 ore lumina si furajate cu nutret caracteristic pasarilor adulte. Aceasi interventie s-a realizat la varstele de 18 si 20 saptamani formandu-se loturile L2 si L3. Modificarile din sfera genitala s-au evidentiat bisaptamanal urmarindu-se caracteristicile fenotipice, greutatea si lungimea aparatului genital, intensitatea de ouat, greutatea medie a oualor, caracteristicile materialului spermatic. De asemenea s-a recoltat sange pentru determinarea nivelului FSH si LH, iar la 18, 22 si 24 saptamani in cazul cocosilor fotostimulati si intretinuti la 8 ore lumina au fost recoltate probe din testicul si canalele deferente pentru analize histologice.
La puicute indicii de reproductie urmariti sunt influentati de durata programului de lumina si varsta pasarilor la care acestea se aplica. Datele obtinute arata ca inceperea stimularii luminoase la 18 saptamani este favorabila obtinerii de productii ridicate si corespunde particularitatilor materialului biologic analizat.
Declansarea activitatii de reproductie, la cocosei inaintea varstei de 20 saptamani mareste durata de timp in care aparatul genital ajunge sa functioneze la nivelul caracteristic si sa produca material spermatic de calitate ce poate fi folosit pentru reproductie. La cocosi varsta are o influenta mult mai mare asupra reproductiei decat la femele, iar ca urmare precocizarea reproductiva nu da rezultate.
A sample of young 60 hens and 40 roosters of Rhode Island breed were divided in groups L1, L2 and L3. Individuals in group L1 were transferred at the age of 16 weeks from 8 h light/ day to 16 h light/ day and fed with a normal adult poultry feed. The same switch was performed with groups L2 and L3 at the age of 18 and respectively 20 weeks. Modifications of the sexual traits were recorded including: phenotype, weight and length of the genital tract, laying intensity, average egg weight and semen parameters. Furthermore, blood samples were analysed for FSH and LH. From photo stimulated roosters -kept under an 8 h light/ day programme at the age of 18, 22 and 24 weeks- histology samples from testis and deferens ducts were analysed.
In young hens reproductive parameters are influenced both by light length and the age when this photo stimulation occur. All data shows that starting photo stimulation at 18 weeks has positive effects on the egg production in the analysed population.
In young roosters inducing sexual stimulation before the age of 20 weeks will prolong the time length to typical reproductive activity and also will affect the semen quality. Thus, it seems that age is more important for young roosters in achieving reproductive maturity than in young hens. Therefore, inducing early sexual development is rather detrimental for males.

Cuvinte cheie: reproductie, puicute, cocosei, precocizare, morfologia aparatului genital, gonadotropine, histologie, productie // reproduction, young hens and roosters, precocity, genitalia morphology, gonadotrophines, histology, production

URL: http://www.agr.hr/jcea