• Korean Journal of Agricultural Science
• /
• v.2 no.1
• /
• pp.9-47
• /
• 1975

These experiments were caried out to study the effects of caponization and various hormone treatments upon meat production and improvement of meat quality of growing chicken. Sixtyseven days old 160 New Hampshire cockerels were treated and growth rate, carcass yield, change of weight of individual organs, meat composition and change of amino acid were measured and analysed. Otherwise change of testis and thyroid gland by hormone treatment were investigated histologically. The results obtained were as follows. 1. The effectst of caponization and hormone treatment upon meat production were; 1) Body weight of cockerels in D. E. S. group without caponization was increased. upon 96.86% than initial period and A. C. T. H. group was 104.22% but other groups and all carponization groups were lighter than those of control group. 2) Weekly body gain of D. E. S. group without caponization was best showing the significance (102.69 g) and the group with caponization were lower than those groups without caponization. 3) Carcass yield was best in Testo. group without caponization (831.2 g) and the group with caponization were lower than the group without caponization. 4) Carcass rate was highest in A. C. T. H. group with caponization and (67.22%) lowest in Testo. group without caponization (63.37%), but any significance was not recognized. 2. The effects of caponizatitn and hormone treatments upon the coposition of meat and amino acids were; 1) Any significance was not recognized between treated and untreated group about change of moisture, crude protein, crude ash and glycogen contents in meat. 2) Fat co tent in muscle in the all treated groups were higher than that of control group. 3) Extracts of group without caponization were higher than those of groups with caponization. 4) Lysin contents were highest in D. E. S. group with caponization (11. 12/ 16.0 g N) and generelly Testo. group was lower compared with D. E. S. group. 5) Histidine and Arginine contents were higher in the groups with caponization than without caponization. 6) Aspartic acid content were higher in D. E. S. group and A. C. T. H. group without depend on caponization. 7) Treonine content was higher in Testo. group without caponization and in the group with caponization and without hormone treatment compared with those of control group without caponization. 8) Serine content was decreased in the group with caponization and increased by D. E. S. and A. C. T. H treatment groups and glutamic acid was also decreased in Testo. group with out caponization. 9) Cystine content was decreased by Testo. treatment and was not appeared in Testo. group without caponization. 10) Valine content was lower in control group with caponization but significance was not recognized between other groups and control group without caponization. 11) Glycine, Alanine, Methionine. Isoleucine, Leucine, Thyrosine and Phenylalanine contents were not so difference between hormone treated groups and control group without caponization. 3. The effects of caponization and hormone treatment upon the change of organs were: 1) The weight of all organs were heaviest in D. E. S. group without caponization (18.5g) and lightest in A. C. T. H. group without caponization (155. 3g) but no significance was recognized between hormone treatment groups. 2) Heart weight was heaviest in D. E. S. group without caponization (7.46 g) and lightest in Testo. group without caponization (5.95 g). 3) Liver weight was heaviest in D. E. S. group without caponization(32.89g) and lightest in hormone untreated group with caponization(29.66g). Significance was not recognized. 4) Spleen weight was heaivest in Testo. group with caponization (3.22 g) and lightest in D. E. S. group without caponization(2.00g) in contrast with the other groups. High significance was recognized among the groups (P<0.01). 5) Cloacal thymus weight was lightest in D. E. S. group with or without caponization compared with control group without caponization. High significance was recognized among the groups. 6) Muscle fat content was not appeared in A. C. T. H. group with caponization, but it was highly increased in D. E. S. group with or without caponization. 7) Testis weight was lightest in D. E. S. group (0.38g) compared with control group (2.66g). Significance was recognized among the groups. 8) Large intestine, small intestine and cecum weight and length were heavier and longer in D. E. S. group without caponization and control group without caponization was lighter than those of hormone treated groups. 4. The effects of caponization and hormone treatment upon histological change of testis and thyroid gland: 1) The histological change of testis was significantly appeared in D. E. S. group that seminifirous tubles was slowly atrophied, the funtion of spernatogenesis was ceased, spermatocyte was changed as degeneration by pyknosis and karyorrhexis and interstitial cell was also atrophied, but in Testo. and A. C. T. H. group were similar as control group. 2) The histological change of thyroid gland in Testo. and A. C. T. H. groups without caponization were similar to that of control group without caponization, but in D. E. S. group without caponization, was changed squamously. Thyroid gland of the groups with caponization, epithelium of was atrophied and changed squamously as degeneration by pyknosis and karyorrhexis and the function of thyroid gland was slowly ceased in colloid and in hormone treated group with caponization.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.11
• /
• pp.1684-1688
• /
• 2007

This study examined the caponization effects on the muscle characteristics (quality and quantity) of caponized male chickens fed before or after sexual maturity. Healthy and uniform Single Comb White Leghorn chickens were caponized at 3-week-old. Feeding was conducted until 16-week-old in trial 1 or from 12-week-old to 26-week-old in trial 2. Ten sham operated male chickens (Sham) were also assigned to each trial as the control group. Chickens used in both trials were housed in individual cages with each chicken representing one replicate. The results showed that early caponization (3-week-old) significantly increased (p<0.05) body weight and pectoral major muscle weight and percentage at 16-week-old compared to the Sham in trial 1. Caponization significantly increased (p<0.05) the protein content of the pectoral major muscle, but decreased (p<0.05) the ash content. Late caponization (12-week-old) significantly decreased (p<0.05) the ash content, myofibrillar ATPase activity and emulsification capacity of the pectoral major muscle in mature capons (26-week-old) compared to the Sham in trial 2. Early caponization (3-week-old) only increased the weight and protein content of the pectoral major muscle with decreased ash content in 16-week-old capons. Late caponization (12-week-old) showed no affects on pectoral major muscle quantity, while it decreased the ATPase activity and enhanced the emulsification capacity in mature (26-week-old) capons. Hence, the muscle quality improvement was shown as capons were fed to sexual maturity.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.5
• /
• pp.706-710
• /
• 2007

This study was to investigate the caponization effects on bone characteristics in male chickens, and the optimum testosterone implantation dosage on bone characteristics improvement. Healthy Single Comb White Leghorn cockerels were caponized at 12-wk-old and selected at 16-wk-old for a 10-wk feeding experiment. Fifteen intact male and caponized male chickens (capon) respectively were assigned to trial 1. Ten sham-operated chickens and 40 capons (randomly allocated into four treatments) were implanted with cholesterol (1.62 mm i.d., 3.16 mm o.d., $9.24{\pm}0.36$ mg), low (1 mm i.d., 3 mm o.d., $5.88{\pm}0.23$ mg), medium (1.62 mm i.d., 3.16 mm o.d., $9.81{\pm}0.17$ mg) or high dose (2 mm i.d., 4 mm o.d., $16.7{\pm}0.24$ mg) of testosterone in trial 2. The results from trial 1 showed that the tibia length, relative tibia weight, breaking strength, bending moment and stress in intact males were higher than capons (p<0.05). The blood phosphorus concentration in capons was higher than the intact male chickens (p<0.05). Caponization also resulted in more antrums and osteoclasts within periosteum and cortical bone from histological observation. In trial 2, the adverse impact of caponization on the bone breaking strength, bending moment and stress could be alleviated through medium dose testosterone implantation. It appears that caponization reduced androgen secretion hence influenced the biomechanical characteristics of bone (tibia) and these adverse effects could be alleviated through appropriate dose of testosterone implantation.

• Asian-Australasian Journal of Animal Sciences
• /
• v.25 no.7
• /
• pp.994-1002
• /
• 2012

An experiment was carried out to determine the effect of age and caponization on the development blood and bone characteristics development in male country chickens in Taiwan. A total of two hundred 8-wk-old LRI native chicken cockerels, Taishi meat No.13 from LRI-COA, were used as experimental animals. Cockerels were surgically caponized at 8 wks of age. Twelve birds in each group were bled and dressed from 8 wks to 35 wks of age at 1 to 5 wk intervals. The results indicated that the plasma testosterone concentration was significantly (p<0.05) lower in capons after 12 wks of age (caponized treatment after 4 wks) than that of the intact males. The relative tibia weight, bone breaking strength, cortical thickness, bone ash, bone calcium, bone phosphorus and bone magnesium contents were significantly (p<0.05) higher in intact males, while capons had higher (p<0.05) plasma ionized calcium, inorganic phosphorus and alkaline phosphatase concentration. The plasma testosterone concentration, relative tibia weight, tibia length, breaking strength, cortical thickness, bone ash, calcium, and phosphorus contents of intact males chickens increased significantly (p<0.05) with the advance of age. In addition, the relative tibia weight of capons peaked at 18 wks of age, and declined at 35 wks of age. The bone ash, calcium and phosphorus content increased most after 14 wks of age in male native chickens in Taiwan. Also, tibia length and cortical thickness peaked at 22 wks of age. However, the peak of bone strength was found at 26 wks of age. These findings support the assertion that androgens can directly influence bone composition fluxes in male chickens. Caponization caused a significant increase in bone loss at 4 wks post treatment, which reflected bone cell damage, and demonstrated reductions in the relative tibia weight, breaking strength, cortical thickness, bone ash, calcium, phosphorus and magnesium contents, and increases in plasma ionized calcium, inorganic phosphorus and alkaline phosphatase concentration.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.4
• /
• pp.575-580
• /
• 2003

We determined the effect of caponization on the carcass and giblet characteristics, and skin and muscle color in Taiwan country chicken cockerels. Caponized birds were surgically altered at 10 weeks old and were fed growing and finishing diets ad libitum during an eighteen-week experimental period. The results showed that the percentage of dressing, heart, feet, thigh, head and neck were significantly (p<0.05) higher in the intact birds, while the capons had a higher (p<0.05) percentage of abdominal fat, intestine, back, wing and breast. Eviscerated weight, breast width, gizzard, liver and spleen ratios were not affected by the treatments. The breast skin color values for lightness (L*) and yellowness (b*) values in the capons were significantly (p<0.05) higher than in the intact birds, but the thigh and back skin were not significantly（p>0.05）different. Compared with the intact birds, the capons had a significantly (p<0.05) less redness (a*) values in the back skin, but were not significantly (p>0.05) different in the breast and thigh skin. The L* value of the thigh muscle was significantly (p<0.05) greater in the capons than in the intact birds, but were not significantly (p>0.05) different in breast and back muscles. The b* values in the breast, back and thigh muscles of the capons were significantly (p<0.05) greater whereas the intact birds had a higher (p<0.05) a* values in the breast, back, and thigh muscles. Moreover, our findings also indicate that the castration resulted in a significant alteration in dressing percentage, carcass region and organ percentage.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.2
• /
• pp.245-251
• /
• 2006

The aim of this study was to investigate the effects of caponization on the bone characteristics, biomechanical property and histology in Taiwan country chickens fed to market age of 26 wks. Male Taiwan country chickens $D{\times}L_2$ were caponized or sham-operated at 8 wks of age, and selected healthy sham-operated and completely caponized chickens (prominent degenerated comb) were selected at 16 wks old and fed to 26 wks old for the trials. Fifteen intact male chickens (Intact), sham-operated chickens (Sham) and caponized chickens (Capon) were assigned for trial 1, and sixteen Intact and Capon were assigned for trial 2. Results in trial 1 showed that the abdominal fat and relative abdominal fat weights of Capon were significantly heavier than Intact and Sham (p<0.05), while the tibia weight and relative weight were the lightest (p<0.05). The tibia breaking strength, bending moment and stress of Capon were the poorest among groups (p<0.05). The trial 2 produced the similar observation that Capon were significantly lighter than Intact (p<0.05) in the tibia weight, relative tibia weight and their biomechanical properties. On histological determinations, Capon showed a thinner cartilage end and fewer chondrocytes (about 50%) and trabecular, and bigger marrow cavity; while decreased hemopoietic cells number with increased adipocytes than Intact observed by H&E stain and at low magnification. At high magnification, Capon showed a decrease in the chondrocyte size by 33 to 50%, with smaller nucleus located near the cell membrane, and exhibited monocellular form chondrocytes. Capon also showed a less strongly acidic sulfated mucosubstance with weaker dyeing property within cartilage zone, and smaller chondrocytes size by Alcian blue stain.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.3
• /
• pp.438-443
• /
• 2006

This trial was designed to study the caponization effects on the appearance, carcass characteristics, blood constituents and lipid metabolism of Taiwan country chicken cockerels. Cockerels were caponized at 8 weeks of age. Sixteen-week-old chickens, including 10 capons, 5 slips (incomplete caponized male chickens) and 20 normal chickens of equal sexes were selected for a 10 week ad libitum feeding trial. Results showed that the testosterone concentrations in the capons and females were lower (p<0.05) than that of intact males. The comb length, height and weights were also lower (p<0.05). The weight of the slips was between that of the capons and intact males, but was heavier (p<0.05) than that of the capon. The live-weight, carcass weight and shank perimeter in the capons were higher than those of the other groups (p<0.05). Hepatic lipogenic enzyme activity analyses showed that NADP-malic dehydrogenase (MDH) activity in the capons and female chickens was higher than that in intact male chickens (p<0.05). The MDH activity in the slips was between that for the capon and intact male chickens (p>0.05). The abdominal fat weight and relative abdominal fat weight of the capons and females were heavier than that for intact males (p<0.05); the slips were between the capons and intact males. The blood lipid content results showed that the triacylglycerol and cholesterol in the capons were higher than that for intact males (p<0.05). However, the percentage of low-density lipoprotein (LDL) was lower than that in intact male chickens (p<0.05). It appears that the increase in lipid accumulation in caponized male chickens is attributed mainly to an increase in MDH activity and the changes in lipid transportation in the capons.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.3
• /
• pp.401-405
• /
• 2002

An experiment was conducted to determine the effects of caponization on the growth performance, breast and thigh muscles physical properties and fiber diameter of the Pectoralis major and Gastrocnemius pars externa in Taiwan country chicken cockerels. Caponized birds were surgically altered at 10 weeks of age. Birds were fed grower and finisher diets ad libitum during an eighteen-week experimental period. The results indicated that the live weight and feed intake in the capons were significantly (p<0.05) higher and the shank length was significantly (p<0.05) longer than in intact birds. There were no significant (p>0.05) differences in feed conversion and mortality between two treatments at 28 weeks of age. Compared with intact birds, the capons had greater (p<0.05) tenderness in the breast and thigh muscles. Cohesion of the breast muscle in the capons was significantly (p<0.05) better than in the intact birds, but the thigh muscles were not significantly (p>0.05) affected. No treatment differences (p>0.05) were associated with cooking loss, muscle chewiness, and elasticity. The capons had a significantly (p<0.05) smaller fiber diameter in the Pectoralis major, but were not significantly (p>0.05) different in the fiber diameter of the Gastrocnemius pars externa. It is concluded that castration did not depress growth compared with the intact birds, but did improve muscle tenderness. This difference was most pronounced in the thigh muscles.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.7
• /
• pp.1026-1030
• /
• 2011

An experiment was conducted to determine the effects of caponization on the muscle composition, ATP-related compounds, the shear values, the taste panel scores and the muscle fiber areas of Taiwan country chicken cockerels. At 10 wks of age, cockerels were divided into two groups: caponized and untreated. Birds were fed grower and finisher diets ad libitum in an eighteen-week experimental period. Results showed that capons contained significantly greater muscle fat content, less breast and thigh muscle moisture content, shear value and muscle fiber area (p<0.05) than those of intact birds. However, neither treatment groups differed significantly (p>0.05) in breast and thigh muscle protein content. Compared with the intact birds, the capons contained significantly (p<0.05) less muscle ash content in the breasts, but did not differ significantly (p>0.05) in thigh muscle ash content. The breast muscle IMP and ATP+ADP+AMP+IMP contents in the intact birds were significantly (p<0.05) higher than those in the capons. The intact birds had significantly (p<0.05) higher ATP and AMP contents than did the capons as well as significantly (p<0.05) less ADP and inosine (HxR) contents in the thigh and breast muscles. The Hypoxanthine (Hx) content of the thighs in the intact birds was significantly (p<0.05) higher than that in the capons; however, there was an adverse effect on the breast muscle Hx content. The breast muscle K value in the intact birds was significantly (p<0.05) lower than that in the capons. The capons produced significantly (p<0.05) higher taste panel scores than did the intact birds for both flavor and juiciness of thigh muscle as well as for flavor and tenderness of breast muscle.