Thyroid hormone and hens reproductive performance of two local strains
Abstract: The extent to which thyroxin can be beneficial in improving egg production in two local strains after peak of production was studied Eighty Silver Montazah and 80 Gimmizah hens aged 48 weeks were randomly assigned for 4 treatments (20 birds each). Hens were individually subcutaneously (in the neck) weekly injected with 0.1 ml DL-Thyroxin solution to provide 50, 100, and 200 J.lg T4/Kg body weight, for 4-weeks treatment period Birds of the 1st group served as control. DL-thyroxin administration caused increases in serum thyroid hormones in a dose dependent manner in both strains. These effects of treatments were sustained even after the 4-weeks recovery period maintaining the dose dependent manner. Estrogen has decreased significantly as a result of the treatments in a dose dependent manner. Serum progesterone on the other hand increased with the low doses of DL-thyroxin, and vice-versa. These effects of treatments were sustained even after the 4-weeks recovery period During the treatment period egg number of Silver Montazah strain increased significantly with the 50 and 100 pgT/kg bwt. doses, respectively and vice-versa. Egg weight increased significantly with the different doses in a dose dependent manner. Similar effects of treatments on egg production was observed with the Gimmiza strain which was more sensitive to the treatments than the Silver Monrazah. Egg quality characteristics after the treatment period did not differ significantly as compared with control.
Serum calcium decreased in a dose dependent manner, inversely to serum.
After the treatment period shell weight, shell thickness and shell calcium percentage did not differ significantly, although they showed tendency towards decreasing with treatments. Hatchability percentage improved in all thyroxin treatments meanwhile, dead embryos percentage was reduced and day old chickns weights was increased It was concluded that inducing a mild hyperthyroidism can improve reproductive performance of the studied local strains past peak of production depending on the dose and the strain used
Keywords: thyroid hormone, hens, local , strains.
Publication year 2005
Pages 147-165
Availability location معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى - الجيزة
Availability number
Organization Name
City الاسكندرية
serial title Egyptian Poultry Science
ISSN 1110-5623
Author(s) from ARC
External authors (outside ARC)
    سمر احمد النجار جامعة الاسكندرية
Agris Categories Animal physiology - Reproduction
AGROVOC
TERMS		 Egg hatchability. Hens. Progesterone. Thyroid hormones.
Proposed Agrovoc local strains;egg number;Egg quality;shell thickness;shell weight;shell calcium percentage;
Publication Type Journal
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