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Showing 2 results for Ansari-Pirsaraei


Volume 18, Issue 4 (7-2016)
Abstract

Hen aging is accompanied by a disruption of productive performance, namely, egg production. The current study was carried out to investigate how exogenous Growth Hormone (GH) and Testosterone (Ts) change diameters of hierarchal follicles, egg weight, and egg production performance of old laying hens in the late phase of production. To this end, 160 HyLine W-36 laying hens (aged 73 weeks), were injected (single injection) with GH and Ts as follows: Treatment 1: 100 µL distilled water (control group); Treatment 2: 500 µg Ts kg-1 Body-Weight (BW)+50 µg GH kg-1 body-weight; Treatment 3: 500 µg Ts kg-1 BW+100 µg GH kg-1 BW, and Treatment 4: 500 µg Ts kg-1 BW+150 µg GH kg-1 BW. The experiment had four replicates and 10 birds in each replicate in a completely randomized design. The diameters of Small White Follicle (SWF), Large White Follicle (LWF), the First (F1), Second (F2) and Third (F3) largest yellow follicles in treatment 3 were significantly larger than in the control group, in the second week after the injection. Hen-Day Egg Production percent (HDEP), egg mass, and Feed Intake (FI) of treatment 3 were significantly higher than all other groups, during the second week after the injection; besides, HDEP and FI in treatment 4 were significantly more than in the control group. These results suggest that in old laying hen, GH and Ts may positively influence follicular diameters and egg production performance.

Volume 18, Issue 6 (11-2016)
Abstract

This study investigated how exogenous hormones change ovary and liver IGF-I, IGF-IR and IGFBP-II gene expression and egg production performance of 160 laying hens (HyLine W-36), at 73rd week of age when subcutaneously injected with different doses of Growth Hormone (GH) and Testosterone (Ts) as follows: Treatment 1 (Tr 1): 100 µL distilled water (control group); Treatment 2 (Tr 2): Ts 500 µg kg-1+GH 50 µg kg-1 live weight; Treatment 3 (Tr 3): Ts 500 µg kg-1+GH 100 µg kg-1 live weight, and Treatment 4 (Tr 4): Ts 500 µg kg-1+GH 150 µg kg-1 live weight. The birds were randomly assigned to the four experimental groups with four replicates of 10 birds each, in a completely randomized design. Fifth-largest-yellow follicle (F5) and liver samples were taken just 8 hours after hormone injection. Production performance was measured during fourth and fifth weeks after hormone injection. Increase in liver IGF-I mRNA in Tr4 was significantly higher than that in Tr 3 and the control group. The liver IGF-IR gene expressions in all hormone-injected hens were significantly higher than that in the control group. The liver IGFBP-II mRNAs were significantly higher in Tr 2 and 4 compared with the control group and Tr 3. The expressions of IGF-I and IGF-IR mRNAs in F5 wall of the layers in the control group, Tr 2 and 3, and F5 IGFBP-II mRNA in Tr 3 were significantly increased compared to the other groups. Ovulation rate in Tr 3 was significantly higher than other groups. Besides, egg mass of Tr 2 and 3 was significantly more than the control group. Feed intake of Tr 3 significantly differed from the other groups. Treatment 4 had significantly higher feed conversion ratio compared with Tr 2. In conclusion, the results show the positive effects of the exogenous Ts and GH through IGF system on reproduction performance in old laying hen.

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