화학적 거세 및 갑상선 기능조절이 닭의 산육성 증진에 미치는 효과에 관한 연구 = Effects of Diethylstilbestrol Implantation and Thyroid Treatment on Meat production and Quality in cockerels

다국어 초록 (Multilingual Abstract)

This experiment was conducted to improve the meat production and quality of cockerels by controling the function of thyroid and gonad with the hormone preparations.
Three weeks old 180 Rhode island red cockerels were divided into six group : iodocasein treatment group, tapazol treatment group, D.E.S. treatment group, D.E.S.+iodocasein treatment group, D.E.S.+tapazol treatment group and control group. Each group was then divided into two groups of 4 weeks and 8 weeks after treatment, arranging the cockerels 15 each.
Iodocasein of 0.25 per cent of the basal ration and tapazol in dose of 0.3 ㎎ per Kg of body weight were administered with the basal ration, and 0.75 ㎎ of D.E.S. was implanted subcutaneously at the head.
Body weight was measured weekly to investigate the growth rate and daily gain. Sacrifice was done at the certain days after treatment, and carcass percentage and organ weight were observed. Histological observation on thyroid and gonad was conducted at the same time.
The results obtained areas follows;
1. The body weight of D. E. S. group, Tap. group and D. E. S. +Tap. group at the end of experimental period were 1452.37±17.61g and 1473.53±16.18g respectively, showing the increasing significance with P<0.05 as compared with 1305.93±21.67g of control group. Iodo. group and D.E.S.+Iodo. group were lighter than control group, but no significance was recognized.
2. Daily gain and carcass percentage were changed as a similar tendency, showing the significance with P<0.05 after 4 weeks and no significance after 8 weeks. Generally high value was obtained in the group treated with D.E.S. and tapazol.
3. Among the meat compositions any marked difference was not recognized in moisture and crude ash cntents of the experimental groups. Crude protein contents were comparatively more in control group (19.87%) than in treatment groups. As compared with 3.39% of control group, crude fat contents of Tap. grop, D. E. S. group anud D. E. S. +Tap. group were 4.44%, 4.22% and 5.35% respectively.
4. Improved effects on feed convertion rate were obtained in the groups treated with D.E.S. and tapazol. D.E.S.+Tap. group was best : 2.61 on the mean.
5. Comb and wattle weights were changed as a similar tendency, showing the significance with p<0.01 after 4 and 8 weeks. Those of all treatment groups were lighter than of control group, particularly in the groups treated with D.E.S. they were atrophied extremely.
6. Generally weights of head, heart, spleen, gizzard and liver were in proportion to body weight.
7. Whole viscera weight showed the significance with p<0.01 among the treatment groups after 4 and 8 weeks. Those of the groups treated with tapazol and D.E.S. were heavier than of control group.
8. Cloacal thymus weight showed the significance with p<0.05. That of control group was heaviest, being heavier after 4 weeks than after 8 weeks.
Meat production and quality cockerels was improved successively by decreasing more or less the function of thyroid and gonad with tapazol and D.E.S. treatment. Only use of tapazol or D.E.S. was fairly effective. Because the iodocasein administration caused the growth restraint and derease of fats, it was worthless for practical application.