RESUMEN

The efficiency of the musculoskeletal system of broiler chickens, in particular during locomotion and in ensuring its supportive function, depends directly on the adequate function and mechanical endurance of soft tissues, including tendons. However, little is known whether the properties of musculoskeletal soft tissues can be influenced by changes of dietary protein. We substituted soybean meal with raw chickpea seeds as the primary protein source in the diet and studied the effects it had on the mechanical and thermal properties of drumstick tendons in broiler Ross 308 chickens. In the experiment, 160 chicks were divided into 2 groups, receiving in their diet either soybean meal (n = 80) or chickpea seeds (n = 80). The experiment lasted 42 days. The physical condition of the drumstick tendons was analyzed on the basis of a tensile test and the results of thermal denaturation as measured by a differential scanning calorimetry. The mechanical evaluation of tendon tensile strength of the broilers fed with chickpea seeds demonstrated an increase in the ultimate strain (for over 22%, P < 0.04) and total energy absorbed by the tendon until rupture (for over 57%, P < 0.05) as when compared to the group fed with soybean meal. Thermal analysis demonstrated alterations in tendon collagen cross-linking as transition onset temperature decreased (from 63.8 to 61.8°C, P < 0.001), whereas the calorimetric enthalpy increased (from 16.2 to 22.1 J⋅g-1, P < 0.05) in the group fed with chickpea seeds. In summary, this study demonstrated that dietary protein source can impact the physical properties of tendons and showed that thermal analysis can be a useful tool for studying the effect of nutrition on the development and structural changes in tendons of broiler chickens.

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RESUMEN

Investigations on changes in a rifle's barrel temperature during shooting in a rhythm typical for practitioners of Olympic shooting sports are presented. Walther KK300 (cal. 5.6 mm), a typical rifle often used in Olympic competitions, R50 RWS ammunition and a high speed thermographic camera were used in the study. Altair version 5 software was used to process thermal images and a stationary wavelet transform was applied to denoise signals for all the studied points. It was found that the temperature of the rifle barrel does not exceed 0.3°C after one shot whereas the total temperature increase does not exceed 5°C after taking 40 shots and does not affect the position of the hitting point on a target. In fact, contrary to popular belief, the so-called "warming shots" are not done for barrel heating but for cleaning of remnants in the barrel.