The effect of age and castration on the growth rate, blood lipid profile, liver histology and feed conversion in Green-legged Partridge cockerels and capons

Abstract

The surgical castration of male chickens induces hormonal changes, which permanently influence metabolic processes in birds. The aim of this study was to determine the effect of age and castration on the growth rate, feed conversion, lipid profile and histopathological changes in the livers of cockerels and capons. The experimental materials comprised male chickens of the Green-legged Partridge breed (old traditional Polish chicken breed), raised to 28 weeks of age. At 8 weeks of age, 100 birds were castrated. Caponization had a significant effect on the plasma concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triacylglycerols (P<0.05). Fatty degeneration and lymphoid cell infiltration were observed more frequently in the livers of capons than cockerels. Capon carcasses were characterized by increased deposition of abdominal and subcutaneous fat (P<0.05). Total meat weight in the carcasses of cockerels and capons was similar, but the proportions of muscles were different. From 20 weeks of age, the weight of breast muscles was higher, and the weight of leg muscles was lower in capons than in cockerels (P<0.05). Capons were characterized by higher liver weight, higher gizzard weight and lower heart weight than cockerels (P<0.05). The feed conversion ratio (kg/kg BW) was similar in intact cockerels and capons. The values of carcass quality parameters and feed conversion ratio as well as histopathological changes in the liver indicate that Green-legged Partridge capons should be slaughtered at 20 to 24 weeks of age.

Effects of Caponization on Growth Performance and Meat Physicochemical Properties of Crossbred Chickens

“…The assessed groups of birds differed in terms of the internal organ share, and the greatest effect was exerted by the liver and gizzard share, which was significantly higher in sterilized birds. This corresponds to the results obtained by Rahman et al (2004), Chen et al (2006Chen et al ( , 2007, Zawadzka et al (2017) and Murawska et al (2019). The authors indicate that the liver is the main site of fatty acids synthesis in birds, and the increase in its mass may be caused by increased lipogenesis processes.…”

Suitability of layer-type male chicks for capon production

“…Caponization is carried out to produce meat with exceptional flavor (Díaz et al, 2010; Calik et al, 2015; Adamski et al, 2016; Amorim et al, 2016). Previous research revealed increased deposition of fat in caponized birds, in particular abdominal fat and mesenteric fat, which can decrease carcass dressing percentage (Zawacka et al, 2017). On the other hand, the accumulation of lipids in the muscle tissue of capons improves the palatability of meat (Amorim et al, 2016; Gesek et al, 2017).…”

Determinación de la edad propicia para la gonadectomía en pollos criollos

“…However, consumption leveled off in subsequent weeks, being similar to that of the other experimental groups. On the other hand, these differences in consumption due to the effect of castration have not been observed 4,20,22,23 . This variability in food consumption is probably due to various factors, including the genetic line and the place of origin of the chickens 4,17,25 .…”