Original Research Article 98 | Page Int J Med Res Prof.2016; 2(6); 98-102. www.ijmrp.com Relationship between Body Weight Performance and Plasma Thyroid Hormones in Broiler Hens Rabia M. Elwahesh 1 , Khalid M. Ben-Elhaj 2 , Marwan M. Draid 3 * 1 Department of Biology, Faculty of science / agelat, University of Zawia, 16418, Zawia, Libya. 2 Department of Physiology, Biochemistry & Animal nutrition, Faculty of Veterinary Medicine, University of Tripoli, 13662, Tripoli, Libya. 3 Department of Pharmacology, Toxicology & forensic Medicine, Faculty of Veterinary Medicine, University of Tripoli, 13662, Tripoli, Libya. ABSTRACT Aims: To investigate the effect of thyroid hormones Thyroxine (T4) and Triiodothronine (T3) on bodyweight performance in broiler hens. Methodology: The hens were kept in a controlled environment of 50-60% humidity at 31 o C in first two weeks than temperature been decreased to 24 o C with 24 hr light cycle per day, and were treated gently. Water and feed were provided ad libitum for the all hens. The body weight of the birds detected at the day 2nd, 4th, 6 th and 8th week of the experimental period and blood sample detected at the day 14th,28th,42th and 56th day of the experimental period. The data were analyzed by the analysis of variance technique in completely randomized design, while the differences between means were tested by Duncan New Multiple Range Test as per SAS. Results: It was noted that there is a highly significant effect of age, at the level (P ≤ 0.01) on the characteristics of each of the concentration of the hormone T3 and T4 hormone levels and body weight. This study showed that there is a difference in the average concentration of "T4 & T3" for meat birds of different ages. The correlation coefficient manner, "Pearson" between the different qualities of the birds of the meat where it was noted there is a strong inverse relationship between "T4 & T3". Conclusion: We conclude that changes in the concentration of thyroid hormones "T4 & T3" follows the output intensity during period of broiler hens life and body weight. Keywords: Broilers hens, Thyroxine, Triiodothronine, Bodyweight performance. *Correspondence to: Dr. Marwan M. Draid Associate professor Department of Pharmacology, Toxicology and Forensic Medicine, Faculty of Veterinary Medicine, University of Tripoli, 13662, Tripoli, Libya. Article History: Received: 20-10-2016, Revised: 03-11-2016, Accepted: 22-11-2016 Access this article online Website: www.ijmrp.com Quick Response code DOI: 10.21276/ijmrp.2016.2.6.019 INTRODUCTION The thyroid is an endocrine organ and thyroid hormones have multiple effects on vertebrate metabolism and development and the avian gland is similar in many respects to that of mammalian. It is well established that thyroid hormones regulate the energy metabolism of most tissues including liver, kidney, heart, skeletal muscles and brain. 1 In chickens, the plasma levels of thyroid hormones are changed with ambient temperature, age, feeding status and pathophysiologic status. 2-5 In birds as in other vertebrates product hormones are both thyroxine (tetra-iodothyronine or T4) and tri-iodothyronine (T3) and found been extensively investigated in human, animal. However in chickens, there is limited information about the association of thyroid hormones blood levels with growth performance in broiler chicken. In various vertebrates, alterations in the quantity and quality of ingested food influence thyroid function. 6 Many studies demonstrated that the thyroid system is especially sensitive to carbohydrate content in diets. 7-9 Glucose in diet may stimulate the secretion of thyroid hormones, 10,11 especially T4, or may act to enhance T4 deiodination peripherally. 12 Alternatively, other nutritional components of diet, possibly protein, may be involved in the regulation of thyroid function. Lipid on the other hand, did not appear to modify thyroid function in rainbow trout under isocaloric conditions. 13 The greater parts of hormones are secreted as T4, which by the process of deiodination may revert back to reversible T3 (rT3). 14 This process takes place in the peripheral circulation. Secreted hormones circulate almost entirely bound to proteins. Since avian blood plasma does not contain a specific binding globulin, as does mammalian blood, 15 T3 and T4 are almost entirely bound to plasma prealbumins and albumins. 16