| Summary: | 碩士 === 國立中興大學 === 畜產學系 === 89 === Effects of Surgical Caponization and Administration of Estradiol to Chicken Embryos on Daily Activity, Agonistic Behavior, Growth Performance, Carcass Traits and Sensory Evaluation of Males Taiwan Country Chickens
Summary
The Taiwan Country Chicken B×L2 strain, established at the National Chung-Hsing University, were used to study the effects of surgical caponization and administration of estradiol to embryo on the behavioral, growth and carcass traits of male chickens. The three experimental groups were, the capon group, surgically caponized at 8 weeks of age, the E2 group, administrated with estradiol before incubation, and the intact control group. The chicken’s growth and behavioral traits were measured from 11 to 33 weeks of age, and the shear value and sensory evaluation scores of breast and leg meats were tested at 14 and 33 weeks of age. Experimental results are as follows:
For feeding time, the E2 group (19.79%) was significantly higher than the control (16.76%) and the capon group (11.45%). For grooming time, the capon group (22.31%) was significantly higher than the E2 (15.25%) and the control groups (11.94%). For crouching time, the capon group (17.10%) was significantly higher than the E2 (13.15%) and the control group (9.56%). For standing and walking time, the capon group (45.69%) and the E2 group (48.21%) were significantly higher than the control group (58.32%).
Agonistic behaviors were observed at 12~16, 19~23, and 31~35 weeks of age periods. Totally, every pen was observed for 18 hours. It was found that the total frequency of fighting in the E2 (48 times) and the capon group (65 times) were significantly lower than that of the control (296 times). Means of aggressive acts (acts/hour/bird) of the capon (0.956) and the E2 group (2.233) were significantly lower than that of the control (3.246).
For the growth performance, the feed conversion ratio of the E2 group and the capon group were significantly better than the control from 10 to 16 weeks of age, and so was the body weight after 20 weeks of age. The comb size of the capon group was always significantly smaller than that of the E2 and the control group. At 14 and 16 weeks of age, the capon group had the worst feather score, the control had the next and the E2 had the best score. At 24 and 32 weeks of age, both the E2 and the capon group maintained very good condition of feather covering, and their feather scores were highly significantly better than that of the control. At 14 weeks of age, the leg weight and its ratio to carcass weight of the E2 and the capon group were significantly lower than those of the control. At 34 weeks of age, the breast weight and its ratio to carcass weight of the capon group were significantly higher than those of the E2 and the control group.
At 14 weeks of age, the shear value of leg meat of the E2 and the capon group were significantly lower than that of the control. At 33 weeks of age, the shear value of breast meat of the capon was the highest, and that of the E2 was the lowest; for the leg meat, the capon group had the lowest shear value, and the control had the highest value.
The sensory evaluation at 14 weeks of age revealed that, for the breast meat, the E2 group had the highest acceptability score, the control had the next and the capon had the lowest; for the leg meat, the E2 group had the highest tenderness score, the capon group had the next and the control had the lowest. The sensory evaluation at 33 weeks of age found no significant difference among groups for any of flavor, tenderness, juiciness and acceptability scores, except for the color scores of breast meat of the capon group were significantly higher than that of the E2 and the control group.
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