الفهرس | Only 14 pages are availabe for public view |
Abstract SUMMARY This experiment was carried out at the hatchry of the International Poultry’ Company (Nobaria - Alexandria) and Poultry Research Station belonging to the Department of Animal Production, Faculty of Agriculture, Zagazig University, Benha Branch. It was aimed to study the effect of injecting with thyroid hormone preparation (Eltraxin), antithyroidal drug (Carbimazole) and growth hormone on chick’s embryonic development, productive performance and some blood constituents as related to the metabolic processes in broilers. A total number of 1340 eggs from Arbor Acres parent breed were used in this study. Eggs were divided into two divisions according to the incubation relative humidity (48% and 52%). Eggs of each division were then subdivided into ten groups, eggs of the 1st, 2nd and 3rd groups were injected with 0.05,0.10 and 0.15 ug eltroxin, respectively, those of the 4th, 5th and 6th groups were injected with 0.05, 0.10 and 0.15 mg carbimazole, respectively, while eggs of the 7th, 8th and 9th groups were injected with 0.005, 0.02 and 0.04 LU. growth hormone, respectively. Eggs of the 10th group were injected with distilled water and used as control group. Each group were divided into two divisions, eggs of the first division were injected just before incubation (into the air cell) and those of the second division were injected at the 9th day of incubation period (into the embryonic allantoice cavity). All eggs were weighed on days 0,3,6,9, 12, 15 and 18 of incubation. Weight loss was calculated by difference and expressed as a percentage of the initial fresh egg weight. Embryonic mortolity was calculated during the incubation period and experised as a percentage of fertile eggs and classified as early dead (1-6 day), mid dead (7-12), late deed (13-18) and dead during hatch (19-21 day). Hatchability of fertile eggs was calculated. A total number of 960 hatched chicks were randomly selected (24 chicks of each group), wing banded, individually weighed, vaccinated and kept under a similar and standard conditions of management, environment, hygein and nutrition. Each group was injected with the same level of hormone on days 21 and 35 of age. Body weight was weekly and individually recorded to the nearst gram along the experimental period. Weight gain and rate of growth between two successive periods were individually calculated. Feed consumed by all chicks of each treatment was daily recorded, averaged and expressed in grams per day per chick. Feed conversion was then calculated as a ratio between feed intake (gm) and weight gain (gm). Performance index was individually calculated. Economical efficiency was also calculated and carcass quality were measured at the 49th day of age. Plasma thyroxine (T4) and triiodothyronine (T3) were determined at day old, 28 and 49 days of age. Also, plasma calcium, inorganic phosphorus and alkaline phosphatase were determined at the 28th and 49th day of age. Weights of the thyroid, adrenal and pituitary glands were recorded and the thyroid was examined histologically. Results obtained could be summarized as follows: Highly significant effect on egg weight loss was found due to incubation relative humidity (RR). Incubating eggs at 48% RH resulted in an increased egg weight loss during the whole period of incubation (O-18days). Injection time had significant effect on egg weight loss at all experimental period. Eggs injected at the 9th day of incubation significantly higher egg weight loss all over the incubation period. Significant effects on egg weight loss were found due to treatments applied at the period from (0-3) and (9-12) days of incubation. |