ABSTRACT In this study, the effect of replacement of soybean meal with raw chickpea seeds as a primary protein source in the diet of broiler chicks on physical properties of drumstick muscle (m. gastrocnemius) was examined. One-day-old Ross 308 broilers (n=160) were fed soybean meal (n=80) or raw chickpea seeds (n=80) as a primary protein source for 42 days. Drumstick muscles, after dissection and storage for 24 h at 5°C, were subjected to texture profile analysis to determine changes in the structural and material integrity, and the thermal stability of muscle proteins were assessed on the basis of differential scanning calorimetry measurements. Light meromyosin, heavy meromyosin and sarcoplasmic proteins in the meat samples of broilers fed raw chickpea seeds were characterized by higher thermal stability as the higher denaturation temperatures were observed. In addition, the calorimetric enthalpy of denaturation of light meromyosin was significantly higher in the muscles of broiler fed raw chickpea seeds, while higher enthalpy of denaturation of actin was determined in those fed soybean meal. Muscle weight, hardness, and the other evaluated textural traits, did not differ between treatments. In summary, dietary protein source affected only thermal stability of muscle proteins; however, the physiological consequences of these alterations are yet to be determined. This study also showed that thermal analysis can be a useful tool for analyzing the effect of nutrition on the development and structural changes in the muscle tissues of poultry.

ABSTRACT The aim of the study was to determine the impact of caponisation of Polbar (Pb) and Greenleg Partridge (Zk) breeds on the production performance, carcass composition, and the nutrient content and fatty acid profile in the breast and thigh muscles and abdominal fat. From 18 weeks of age to the end of the experiment, the Zk capons were significantly heavier than the cocks. The Zk capons had higher (p≤0.05) weight and share of breast and leg muscles. At 24 weeks of age, we noted an increase in the total content of n-3 PUFA and linolenic acid C18:3 in the breast muscles of the Zk and Pb capons. The content of PUFA and n-3 PUFA in thigh muscles and the n6/n3 ratio were reduced in the Pb capons at 24 weeks of age, compared with the Zk cocks. Caponisation of the Pb cocks had a beneficial effect on the final body weight, feed intake, and slaughter characteristics, in comparison with the non-caponised birds of this breed. A tendency towards an increased total share of PUFA and MUFA, a significantly higher content of n-3 PUFA, and a lower (p≤0.05) n-6/n-3 ratio were found for the breast muscles of the Pb capons. Both breeds are a good material for production of capons. The meat of the capons of both breeds exhibited a beneficial, higher PUFA/SFA ratio, higher n-3 PUFA and MUFA content, and a more favourable n-6/n-3 ratio.

ABSTRACT The aim of this study was to evaluate the effect of adding zinc (Zn) mineral supplements from organic (ZnGly) and inorganic (ZnO) sources to growing male Ross 308 chickens on the mechanical, geometric, and histomorphometrical parameters of long bones. A corn-soybean meal basal diet was supplemented with Zn at 50 or 100 mg·kg-1 of a premix, except the control group (0 suppl). The serum concentration of insulin-like growth factor 1 was higher in the ZnGly50 group compared with the control group. Positive influence of Zn on the femur is highlighted when considering the significant increase in parameters such as mean relative wall thickness, and maximum elastic and ultimate strengths after Zn administration. Zinc supplementation did not affect tibial parameters. The histomorphometric analysis showed a positive impact of Zn supplementation (irrespective of source and level) on femoral trabecular thickness. Rapid loss in actual bone volume in tibial metaphyseal trabeculae was observed with ZnGly at 50 mg·kg-1. In conclusion, this study showed that dietary Zn supplementation positively influences bone mechanical properties, confirming its beneficial effect on the development of the skeletal system and bone tissue of broilers tested for a nutritional-osteoporotic factor. Adverse health effects in trabecular bone as a result of the use of Zn at 50 mg·kg-1 of the premix show that supplementing Zn at the recommended dose (100 mg·kg-1) is essential.