• Asian-Australasian Journal of Animal Sciences
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• v.7 no.3
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• pp.405-411
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• 1994

Purified myofibrils were prepared from ante-mortem stress and control lots of Taiwan country chicken breast and thigh muscles at death and afler storage at $4^{\circ}C$ for 0, 1, 2, 3, and 7 days post-mortem. Sodium dodecyl sulfate polycrylamide gel electrophoresis (3.2%) and densitometer were used to examine the effect of ante-mortem stress and control storage of muscle on titin and nebulin. Results indicated that titin and nebulin were more rapidly degraded in the control and the ante-mortem stress light muscles than in the control and ante-mortem dark muscles of Taiwan country chicken. In contrast, nebulin was shown to be more resistance to degradation in the ante-mortem stress dark muscle than in the control light muscle.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.2
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• pp.103-114
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• 1989

Reciprocal crosses were conducted between three strains of Taiwan Country chickens, developed in the National Chung-Hsing University, and two strains of Single Comb White Leghorns, developed in the Taiwan Livestock Research Institute. Traits studied were growing performances, laying performances, egg quality traits and traits concerning disease resistance, including resistance to Marek's disease virus and immune responses to Newcastle disease virus vaccine and to sheep red blood cell. Results indicated that laying performances of Taiwan country chickens were much inferior to White Leghorns, but they matured earlier, their eggs had better shell strength and larger proportion of yolk, and their general disease resistance was much better than White Leghorns. Heterosis were found in laying performances and egg quality traits. The heterosis in laying traits was so large that the hybrid laid as many eggs and as large eggs as did pure strains of White Leghorns. Strategies on the improvement of native chickens and the utilization of genetic merits of native chickens were also discussed.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.19-24
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• 2008

The purpose of this study was to detect expression of genes related to egg production in Taiwan Country chickens by suppression subtractive hybridization. Liver samples of mRNA extraction from two Taiwan Country chicken strains (L2 and B), originated from the same population but with very distinct egg production rates after long-term selection for egg and meat production respectively. Two-way subtraction was performed. The hepatic cDNA from the low egg production chickens (B) was subtracted from the hepatic cDNA from the high egg production strain (L2). The reversed subtraction (L2 from B) was also performed. The resulting differentially expressed gene fragments were cloned and sequenced. We sequenced 288 clones from the forward subtraction and 96 clones from the reverse subtraction. These genes were subjected to further screening to confirm the differential expression between the two genetic breeds of chickens. The apolipoprotein B (apoB) was expressed to a greater extent in the liver of the L2 than in the B line chickens. The 5-aminoimidazole- 4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase (PURH) was expressed to a greater extent in the liver of the B than in the L2 strain chickens. We demonstrated that both apoB and PURH were more highly expressed in the liver than that in other tissues (muscle, ovary, and oviduct) in laying Taiwan Country chickens. Taken together, these data suggest that after the selection for egg production, expression of apoB and PURH genes were also changed. Whether the changed expression of these genes is directly related to egg production is not known, but these two genes may be useful markers for egg laying performance in Taiwan Country chickens.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.9
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• pp.1348-1354
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• 2003

The feeding value of high-oil corn fed to Taiwan Country (TC) chicken was examined by measuring apparent metabolizable energy (AME), growth performance, sexual maturity, carcass characteristics, and plasma pigmentation. In a completely randomized design, 870 sex-intermingled one-wk-old chicks were assigned to one of 30 floor pens, 29 birds per pen, and each pen randomly assigned to one of five dietary treatments. The experiment was ended when birds were 16 wk of age. The five dietary treatments varied in main fat sources, which were corn oil (CO), high-oil corn (HOC), lard (LRD), whole soybean (WSB) and yellow corn (YC), respectively. All the diets were formulated isonitrogenously, isocalorically, and of equal lysine and methionine contents except YC, in which equal amounts of YC replaced HOC. The results indicated that feed conversion in HOC was 8% higher (p<0.05) than YC whereas the calculated AME of HOC was only 3.5% to 4.0% higher than that of YC. No significant differences were observed in body weight, body weight gain, feed consumption, feed conversion ratio and ME efficiency for body weight gain among CO, HOC, LRD, and WSB. No significant differences existed in both skin and muscle pigmentation of breast among the five dietary treatments. No significance differences existed in plasma carotenoid content measured at various ages among the five dietary treatments except that birds fed with HOC had less (p<0.05) plasma carotenoids at 16 wk-old. The results indicate that if the price of high-oil corn is no more than 1.05 times that of yellow corn, the dietary cost per kg of body weight gain for TC chickens fed diets containing high-oil corn will be less, although their body weight may be lighter compared to chickens fed diets formulated with other fat sources.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.50-56
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• 2003

An experiment was carried out to compare the body weight, shank length, rectal temperature, comb area, abdominal fat, blood parameters and bone traits of capon, slip and intact birds in Taiwan country chicken cockerels. One hundred and sixty-six Taiwan country chicken cockerels were randomly assigned to caponized or intact male groups. Caponized birds were surgically altered at 10 weeks old and raised to 28 weeks old. At 28 weeks of age, the capons were separated into capon and slip groups, depending on the atrophy of the comb and wattle in size. The results showed that body weight and shank length in slips were significantly (p<0.05) greater than in intact birds. Intact birds had the highest (p<0.05）feather scores and the lowest (p<0.05) rectal temperature. Compared with intact birds and slips, capons had a significantly (p<0.05) smaller comb area. Bone percentage, stress and cortical thickness, and bone and ash calcium content and plasma testosterone concentration, in intact birds were the highest (p<0.05) followed by slips and capons. However, intact birds had the lowest (p<0.05) plasma ionized calcium and phosphorus concentrations. Bone and ash manganese contents in capons were significantly (p<0.05)lower than those in others. These findings support the hypothesis that androgenic effects on secondary sexual characteristics are stronger than anabolic growth promoting response. Androgens can directly influence calcium fluxes in male chickens. Caponized caused a reduction in the bone percentage, stress, cortical thickness and bone calcium content.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.3
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• pp.401-405
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• 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
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• v.19 no.3
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• pp.438-443
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• 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
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• v.16 no.4
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• pp.575-580
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• 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
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• v.24 no.7
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• pp.1026-1030
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• 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.

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