Effects of Caponization on Growth, Blood, Carcass and Bone Characteristics in TLRI Native Chicken Cockerels Taishi Meat No. 13

• Main Authors: Cheng-Yung Lin, 林正鏞
• Other Authors: Jenn-Chung Hsu
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/21552594883863410723

博士 === 國立中興大學 === 畜產學系 === 91 === The objectives of this study were (1) to compare differences in growth, blood, organ and carcass part ratios, skin and muscle color, mucle compositions, ATP-related compounds, physical properties and sensory panel scores, and bone mechanical traits and mineral contents, between male and caponized TLRI native chicken Taishi Meat No.13; (2) to establish caponization and slaughter age, and dietary calcium level effects on the growth, blood, carcass and bone characteristics in caponized TLRI Native Chicken Taishi Meat No. 13. These data can be used to improve foot weakness and determine the optimal caponization and marketing age in caponized TLRI Native Chicken Taishi Meat No. 13. Caponized birds were surgically altered at 6 to 14 weeks old. The results indicated that the capons had significantly (P < 0.05) higher rectal temperature, live body weight, feed intake, shank length, feather integrity, abdominal fat and intestine ratios, back, wing and breast part ratios, muscle fat and inosine contents, skin and muscle L* and b* values, breast muscle K value and cohesiveness. Capons also had higher (P < 0.05) plasma Ca2+, K+, inorganic phosphorus, triglyceride, total cholesterol, HDL, LDL, albumin, globulin, total protein, creatine kinase and calcitonin concentrations than male had. Capons had lower（P < 0.05） dressing percentage, heart, head and neck and thigh part ratios, muscle moisture, protein, breast muscle IMP and ATP+ADP+AMP+IMP and thigh muscle hypoxanthine contents, muscle a* value, cooking loss and toughness , Pectoralis major fiber diameter, PCV and plasma pH than male had. Capon also had lower (P < 0.05) plasma uric acid, creatinine, testosterone and total hydroxyproline concentrations, relative tibiae length, bone percentage, breaking strength, cortical thickness, bone ash, Ca, P and Mg contents than male had. No significant difference (P > 0.05) was observed in feed conversion, flock uniformity, breast width, gizzard, liver and spleen ratios, muscle elasticity and chewiness, thigh muscle cohesiveness, Gastrocnemius pars extrna fiber diameter, and total calcium, parathyroid hormone, magnesium, alkaline phosphatase, Na+, Cl- and thyroxine plasma concentrations, and tibial length between the capons and intact birds. However, the Gastrocnemius pars extrna fiber diameter and plasma thyroxine concentration trended to be lower (P < 0.10) in the capons. The sensory panel scores for thigh muscle flavor and juiciness and for breast muscle flavor and tenderness for the capons were significantly (P < 0.05) higher than that for males. Sensory panels scores for thigh muscle tenderness and breast muscle juiciness showed no significant difference. However, the capons tended to have higher scores (P < 0.10). The slips had significantly (P < 0.05) higher comb area, spleen ratio, and bone Mn content than capons. Significantly (P < 0.05) higher live body weight, shank length, rectal temperature, feather integrity and skin L* value in slips than those in intact birds. The slips also had significantly (P < 0.05) higher plasma Cl- concentration than capons or intact birds. Other characteristic values measured in slips, such as dressing and carcass part percentages, skin and muscle color value, muscle compositions, toughness and fiber diameter, PCV, plasma pH and compositions, relative bone percentage, breaking strength, cortical thickness and bone ash and mineral contents were between those for capons and intact birds. Most of these values in slips were closer to capons than intact birds. Live body weight, feed conversion, plasma creatinine, uric acid, triglyceride, total cholesterol, Ca2+, inorganic phosphorus, total calcium/inorganic phosphorus and alkaline phosphatase concentrations, dressing percentage, thigh, wing, breast, back, head and neck part ratios, muscle fat, moisture, protein, IMP, hypoxanthine, inosine contents and K, L*, a* and b* values, cooking loss, shear value, muscle sensory panel scores for flavor, juiciness and flavor, relative bone percentage, breaking strength, cortical thickness, bone ash, Ca, P and Mg contents were significantly (P < 0.05) influenced by caponization and the slaughter age. However, the foot part ratio and plasma magnesium concentration were significantly（P < 0.05）influenced by slaughter age only. Mortality of caponized after 24 hours, plasma alkaline phosphatase and albumin concentrations, liver ratio, skin b* value, muscle L* value, muscle fat content and cooking loss, Gastrocnemius pars extrna fiber diameter and area increased with increasing age at caponization, whereas the mortality of caponized within 24 hours, plasma creatinine concentrations, heart ratio, muscle moisture and protein contents decreased with increasing age at caponization. Caponized effects were first observed in plasma compositions (caponized treatment after 4 wks) followed by of carcass part ratios, muscle color, composition, cooking loss, shear value and bone characteristics（caponized treatment after 6 wks）, and dress percentage and sensory panel scores（caponized treatment after 10 wks）. The optimal caponization age was before 8 weeks of age for mortality, slip ratios and meat quality, and the optimal marketing age was 24 wks of age for B.W. gain and feed conservation. After 22 weeks of age, birds had better carcass traits and eating quality than birds before 18 weeks of age. Raising calcium content to 1.1% did not affect growth performance, carcass characteristics and meat quality, or improves bone characteristics of the capons from 9 to 26 wks of age. The results of this study indicated that androgenic effects on secondary sexual characteristics are stronger than those promoting anabolic growth responsein testosterole. High testosterone tended to inhibit the growth performance of chickens and that appeared to have a concentration threshold. Testosterone can directly influence bone composition fluxes in male chickens. Caponization resulted in increasing cancellous and cortical tibiae bone skeletal loss in young chickens. Testosterone can increase bone deposition and suppress bone resorption. Live weight, shank length, rectal temperature, feather integrity, skin and muscle color values, carcass characteristics, muscle compositions, toughness, fiber diameter, packed cell volume, plasma pH value and compositions, and eating quality were significantly (P < 0.05) influenced by caponization.