The present experiment was conducted in order to evaluate the effects of caponization on growth, carcass composition and meat quality of males of a layer line reared until the 34th week of age. Two ...hundred and fifty males of a layer line were purchased and randomly divided in two equal groups: intact males and capons. Caponization was conducted at 45 days of age. Three slaughters were performed at the ages of 26, 30 and 34 weeks of age. Caponization did not affect feed intake and final live weight. Capons had a heavier breast and lighter leg than intact males. Lipid accumulation was enhanced by the caponization and fat was stored mainly at the fat pad and the skin of the commercial parts excluding the drumstick. The Pectoralis major muscle of capons had higher intramuscular fat content, lightness (L) and yellowness (b*) values and lower redness values (a*). In conclusion, caponization could be applied to a layer genotype in order to produce commercial chicken meat.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper analyses the effect of caponisation at 8 weeks on growth and on carcass and meat characteristics of Castellana Negra chickens slaughtered at 29 weeks. Caponisation did not result in weight ...improvements as compared with uncastrated birds. No changes were observed in the growth rate or in the parameters determining the point of inflection in the growth curve (sexual maturity). Regarding carcass characteristics, castration resulted in a wider breast angle and heavier pectoral muscles in caponised birds than in uncastrated birds, but with no differences in thigh and drumstick weight and length. Capon meat showed a higher fat content than that of cocks, making it juicier and less fibrous. No differences were found in fatty acid content (C 14:0, C 18:0, C 18:1 and C 18:2). Nor were there any differences in colour measurements, pH or water loss from the meat. While cocks' thighs + drumsticks were found to be tougher than their breasts, there were no such differences in capons because after castration, thigh + drumstick meat became more tender.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study investigated gender, caponization and exogenous estrogen effects on lipids, bone and blood characteristics in Taiwan country chickens. Thirty male chickens were caponized at 8 weeks ...(capons); 15 capons were injected with estrogen (5 mg/bird estradiol 3‐benzoate) every 2 weeks from 8 to 28 weeks, and 15 sham‐operated male (shams) chickens and 15 females were selected for this trial. The results showed that the shams had lower relative abdominal and chest subcutaneous fat than females (P < 0.05). The estrogen‐treated capons had greater relative abdominal and chest subcutaneous fat than shams and capons (P < 0.05), which might result from higher blood very low‐density lipoproteins and triacylglycerol concentrations (P < 0.05). Caponization could dramatically increase relative abdominal fat (506%; P < 0.05). The shams had higher tibia weight and biomechanical properties, such as maximum bone strength and bending moment values than the capons (P < 0.05). Tibia biomechanical properties were reduced by estrogen treatment (P < 0.05). The females obtained the lowest biomechanical value in all treatments (P < 0.05). Histological examination revealed cavity formation in the cortical bone of estrogen‐treated capons and female chickens, which suggested that estrogen reduced bone biomechanical properties by destroying its structural integrity.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
This study examined the effects of caponization and different exogenous androgen implantations on the growth performance and muscle characteristics of caponized male chickens. Male Single Comb White ...Leghorn chickens were caponized at 12 wk of age and selected at 16 wk of age for a 10-wk feeding period. Sixteen intact males and caponized (capon) chickens each were assigned for trial 1. Sixteen sham-operated male chickens (sham) and 64 capons were selected for trial 2, in which capons were randomly divided into cholesterol (CHOL), testosterone (TES), 5α-dihydrotestosterone (5α-DHT), or 19-nortestosterone (19-NorT) implantation at 16, 20, and 24 wk of age, with feeding to 26 wk of age. The result from trial 1 showed that caponization improved BW gain and feed conversion rate (P < 0.05) and decreased the comb length, height, and weight (P < 0.05). Breast muscle weight and gastrointestinal tract weight were higher in capons compared with intact males (P < 0.05). In trial 2, CHOL implantation decreased relative thigh muscle weight compared with the sham (P < 0.05), and only 19-NorT implantation increased relative thigh muscle weight to the compatible level with the sham (P > 0.05). 19-Nortestosterone and 5α-DHT implantations showed lower crude fat in the pectoral major muscle than CHOL (P < 0.05) and reached a compatible level with the sham (P > 0.05). All androgen implantation groups showed higher myofibrillar ATPase activity than CHOL (P < 0.05), and 19-NorT and 5α-DHT had the highest level (P < 0.05). Only 19-NorT implantation demonstrated higher shear value than CHOL (P < 0.05) to the compatible level with the sham (P > 0.05). Androgen implantation increased emulsifying capacity compared with CHOL (P < 0.05) and reached a compatible level with the sham (P > 0.05). Caponization decreased the blood TES concentration in male chickens, leading to changes in growth performance and muscle characteristics. After different androgen implantations in capons, 19-NorT showed the most effective results in increasing muscle quality and quantity, followed by the 5α-DHT and TES.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A two‐trial experiment was conducted to evaluate the effects of caponization on fat metabolism‐related biochemical characteristics of broilers. Male Redbro broilers were purchased, caponized at 3 ...weeks and reared until either the 18th (Trial 1) or the 24th (Trial 2) week. In Trial 1, five slaughters were performed at 6, 9, 12, 15 and 18 weeks of age while in Trial 2 one slaughter at the end of the experiment (24 weeks). In each slaughter, the abdominal adipose tissue cellularity, the NADP dehydrogenase activity in the liver and some serum lipoproteins concentrations were assessed. Caponization had a marked effect on the adipocyte volume and NADP‐malate dehydrogenase activity in the liver at 24 weeks but it did not affect adipocyte number or the activity of NADP‐isocitrate dehydrogenase activity at any age (p < 0.05). Regarding the lipoproteins, cholesterol and HDL‐cholesterol were elevated in capon serum at 18 weeks of age while no difference was detected in the triglyceride concentration at any age. In conclusion, a relationship between fat deposition at the phenotypic level and the level of lipogenic enzymes and lipoproteins capons was established but not as pronounced as expected as some parameters displayed a constant increasing pattern while others did not.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Capons of three genotypes (Barred Prelux, Sulmtaler, Styrian hen) were fattened outdoors and slaughtered at two ages (163 and 198 days). Cockerels were caponised at age 47 days and at age 84 days ...were moved to grower houses with free access to pasture. Animals had ad libitum access to food and water. Ten carcasses of each genotype and age were sampled at slaughter for sensory analysis. The four trained panellist assessed three traits of raw carcasses on scale 1–5 and 19 traits on roasted carcasses on scale 1–7. Shear force was measured on cooled meat slices by apparatus Texture Analyser, TA.XT plus, Volodkevich contact cell. Statistical analysis was performed by MIXED procedure in SAS/STAT. Age at slaughter affected nine, genotype five and interaction between age and genotype three sensory traits. Shear force differed among genotypes and it got worse at older age. Any of three genotypes was not superior in most of sensory traits. Thus, decision which genotype to fatten and how long depends on preferences and importance of certain sensory traits by consumers.
This study determined the caponization effects on the immune responses in male chicks. Different forms of exogenous androgen implantation on male chick immunity were compared. Healthy, uniform male ...Single Comb White Leghorn chicks were caponized at 3 wk of age. Birds were housed in individual cages (35 x 30 x 40 cm, length x width x height). Each of 27 sham-operated (sham) and caponized (capon) male chickens were used for trial 1. Trial 2 used 60 capons divided into 4 treatments with implants of either 1 mm i.d. x 3 mm o.d. 58 mg of cholesterol, testosterone (TES), 5α-dihydrotestosterone (5α-DHT), or 19-nortestosterone (19-NorT). The exogenous androgen was implanted immediately after caponization and resupplied every 4 wk for an entire 13-wk feeding trial. The results from trial 1 showed that the relative bursa weight increased compared with the sham treatment (P < 0.05). The 2 wk post-Newcastle disease virus titer and the delayed-type hypersensitivity (DTH) of 48 h post-phytohemagglutinin phosphate (PHA-P) injection were increased compared with the sham treatment (P < 0.05). In trial 2, implanted 5α-DHT and 19-NorT could decrease the relative bursa weight in capons (P < 0.05). The 2 wk post-Newcastle disease virus titer in the 5α-DHT group was higher than that in the cholesterol group (P < 0.05). The 19-NorT group had the highest (P < 0.05) PHA-P response. Peripheral blood lymphocyte subset population analysis revealed that the percentage of CD4 T cells in the TES group was lower (P < 0.05) compared with that of the 5α-DHT group. Differently, the percentage of CD8 T cells in the TES and 19-NorT groups was higher (P < 0.05) than that in the 5α-DHT group. Male chicks that were caponized had increased bursa weight and PHA-P response, whereas different forms of exogenous androgen implantation reverted the phenomena in an order of potency of 5α-DHT and 19-NorT > TES, and the PHA-P response was TES > 5α-DHT >19-NorT.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study examined the effects of caponization using different doses of testosterone (TES) on sexuality, hematology, and immune responses in male chickens. Healthy male chickens were caponized at 12 ...wk of age and selected at 16 wk of age for a 10-wk experiment. Fifteen intact male and 15 caponized male chickens were assigned to trial 1. In trial 2, ten sham-operated male chickens (sham) and 40 capons (randomly divided into 4 treatments) were implanted with cholesterol (CHOL, 9.24 ± 0.36 mg), low TES (5.88 ± 0.23 mg), medium TES (9.81 ± 0.17 mg), or high TES (16.7 ± 0.24 mg) administered at 16, 20, and 24 wk of age. Results from trial 1 showed caponization decreased the comb length, height and weight, and hematocrit (P < 0.05) and increased the hemagglutination inhibition (HI; 1 wk postchallenge) and hemagglutination titer after Newcastle disease virus (NDV) and SRBC injections (P < 0.05). In trial 2, the medium TES increased the comb length and height as compared with the CHOL group. Only the high TES increased the comb weight (P < 0.05). The HI titer (1 wk postchallenge) in the CHOL group was higher than the sham (P < 0.05). The medium TES decreased the HI titer (P < 0.05) to the level of the sham (P > 0.05). The phytohemagglutinin response was higher in the high TES group 24 h postinjection (P < 0.05) and in the medium TES 48 h postinjection (P < 0.05) as compared with the CHOL group. High dose TES implantation decreased the white blood cell counts as compared with the CHOL and sham groups (P < 0.05). It appears that caponization decreased the blood androgen concentration and enhanced the humoral (anti-NDV and anti-SRBC) immune response. Testosterone implantation up to a threshold concentration could inhibit the humoral (anti-NDV) immune response and increase the cell-mediated (phytohemagglutinin) immune response.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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