A field study of welfare status in four strains of commercial broiler chickens kept under intensive rearing conditions.

الملخص EN

Background : studies of welfare status in commercial broiler chickens in Egypt were still not including all welfare indicators.

The purpose : the present study was designated to investigate the welfare status in the previously studied commonly reared broiler strains in Upper Egypt in terms of hormonal assay, immunological and productive traits when they were kept collectively under the same husbandry conditions.

Methods : strains under investigation were Avian 43, Hubbard, Ross and Cobb.

Firstly, tri-iodothyronine (T3) and growth hormone (GH) were measured.

Secondly, Heterophil to lymphocyte ratios (HLR.s) were also measured as an indicator to slight and moderate physiological stress and in addition to their indication about cellular immunity.

Thirdly, the hum oral immune component was estimated by measuring haemagglutination inhibition (HI) titer to Newcastle Disease Virus (NDV) antigen.

Results: Serum GH levels were lower in Ross and Cobb strains when compared with Hubbard and Avian 43 strains at 2nd and 4th weeks old.

On the other hand serum T3 levels were significantly higher in Ross and Cobb strains when compared with Hubbard and Avian 43 strains at 2 weeks old.

Therefore, the higher serum T3 levels at first 2weeks the higher were the feed conversion and final body weight.

These results indicated that T3 has more impact on body weight gain than GH in commercial broiler strains in broiler chicken reared under intensive housing systems.

HLRs were significantly increased with ages in all strains, but HLRs were higher in Avian 43 and Hubbard broilers when compared with Ross and Cobb broilers at 4th and 6th weeks of age.

Conclusion : welfare status in terms of immunity and stress tolerance was higher in Ross and Cobb broilers when compared with Avian 43 and Hubbard broilers.

Therefore, the high welfare status could be translated into high productive performance in commercial broilers that kept under intensive rearing conditions in Upper Egypt.