Técnicas de diagnóstico in vivo e estratégias para mitigação das miopatias peitorais em frangos de corte

Abstract

This thesis is divided into three chapters: CHAPTER I – This is a systematized review with the aim of contextualizing, quantifying and qualifying research on nutritional strategies for mitigating White striping and Wooden breast myopathies. It was observed that several strategies are being employed by the industry with the aim of mitigating the incidence of pectoral myopathies. Most of these strategies are classified as approaches related to growth rate (change in the chicken's growth curve) and the use of dietary antioxidants (natural or synthetic). Approaches related to the growth curve aim to manipulate or slow down the growth of birds throughout the productive phase or incertain phase and, thus, reduce the severity of myopathies. However, most dietary manipulations that mitigate the appearance and severity of myopathies result in impaired animal performance.CHAPTER II – The aim of this study was to validate infrared thermography and ultrasound techniques as predictive diagnostic tools for pectoral myopathies, as well as to study the allometric growth of different parts of the body and the quality of meat in broiler chickens affected by pectoral myopathies. The surface temperatures of the 300 birds breast’s were recorded, followed by the ultrasound images for subsequent echogenicity. The birds were slaughtered and cuts were made to weigh the body parts, then the breasts were evaluated for the presence and severity of myopathies. From this, nine treatments were established, represented by the associated degrees of White striping and Wooden breast myopathies and breasts classified as normal. There was no difference in surface temperatures and echogenicity values between normal breasts and affected breasts. The most severe score of wooden breast affects meat quality variables. CHAPTER III – The aim of this study was to evaluate the effect polyphenol blend (Silvafeed ATX®) on performance, pectoral myopathies, carcass yield, body growth, meat quality, antioxidant potential and lipid profile. 1,280 one-day-old chicks were housed and distributed in four treatments that consisted of the administration of different polyphenol blend doses in the diet (Control, 250, 500 and 1,000 g/ton). Polyphenol blend positively influenced feed consumption, weight gain, feed conversion and the production efficiency index, which calculated at 514 g/ton. The breast grew later than other parts of the body in birds fed with 500 g/ton of the extract, demonstrating the efficiency in modulating the growth of the pectoral muscle. These indices are directly linked to the development of Wooden breast, which obtained lower degrees of severity estimated at 652 g/ton at 42 days of age. Polyphenol blend did not influence White striping. The extract promoted meat tenderness and antioxidant status.Furthermore, the blend influenced the lipid profile of the muscle, impacting some specific fatty acids and reducing omega 3 concentrations. We concluded that the polyphenol blend reduced the occurrence of more severe degrees of Wooden breast and promoted improvements in meat performance and tenderness in adjusted doses. We concluded that polyphenol blend reduces the occurrence of severe degrees of Wooden breast and promoted improvements in performance and meat tenderness in adjusted doses.