Níveis de cromo na dieta de codornas de corte e postura criadas em clima quente

Abstract

This thesis is presented in six chapters, consisting of a literature review, a systematic review, two articles from Experiment 1, and two articles related to Experiment 2. CHAPTER 1: The objective of the literature review was to explore the current landscape of quail farming in Brazil, the importance of thermoregulatory capacity, thermal comfort of the birds, and the impact of the production environment on the behavior, welfare, and health of broiler and layer quails. Despite its significant expansion and Brazil's considerable production of quail meat and eggs, the production environment, due to the great variability of climates and microclimates in the country, poses daily challenges, necessitating the development of strategies to mitigate the negative impact of high temperatures and thermal stress in quails. CHAPTER 2: The study aimed to synthesize the history, evolution, and current results reported in the literature regarding the forms of chromium (Cr) administration, its applications for all productive characteristics, quality of by-products, and health of the bird species most commonly used for food production, including barriers, perspectives, as well as the potential of chromium in reducing thermal stress and improving welfare. Following the PRISMA protocol, a total of 73 studies were included. It was concluded that the action of Cr in increasing serum insulin concentration, reducing glucose, and the hormones corticosterone and cortisol seems to be quite clear, and these physiological changes have proven crucial for improving the immune system, lipid profile, and enhancing the performance of production birds. There is greater effectiveness of Cr in the diets of birds subjected to stress, making supplementation more advantageous in challenged production birds. The beneficial effects of Cr on poultry products were identified only in terms of productivity and yield, but its quality remains unchanged, except for a reduction in fat deposition. Cr supplementation is recommended for thermally stressed birds at doses of 0.6 to 1.2 mg/kg of broiler diet and 0.6 to 1.0 mg/kg for quail and laying hen diets. Cr is not recommended in the diets of animals raised under normal conditions, as the typical levels found in diets, although variable, are sufficient for broilers (0.5 ± 0.15 mg/kg), quails, and laying hens (0.3 ± 0.2 mg/kg). CHAPTER 3: This study aimed to evaluate the effects of chromium picolinate supplementation in the diet of European quails raised in a hot climate on performance, carcass characteristics, intestinal biometrics, bone development, and lymphoid organ development. A 26 total of 300 quails (Coturnix coturnix) were used, distributed in a completely randomized design with five treatments, six replications, and ten birds per experimental unit, supplemented with 0, 0.30, 0.60, 0.90, and 1.20 mg/kg of chromium picolinate for 35 days. Supplementation with 1.2 mg/kg of chromium picolinate in the diet of European quails up to 35 days of age raised in a hot climate increases performance, lymphoid organ development, and intestinal biometrics, while reducing abdominal fat without harming bone development. CHAPTER 4: This study aimed to evaluate the influence of chromium picolinate supplementation in the diet of European quails raised in a hot climate on thermoregulatory response, physiological parameters, behavior, and feathering score. A total of 300 quails (Coturnix coturnix) were used, distributed in a completely randomized design with five treatments, six replications, and ten birds per experimental unit, supplemented with 0, 0.30, 0.60, 0.90, and 1.20 mg/kg of chromium picolinate for 35 days. The use of 1.2 mg/kg of chromium picolinate in the diet of European quails raised in a hot climate increases thermoregulatory capacity and decreases physiological responses and stress-related behaviors. CHAPTER 5: This study aimed to evaluate the potential of chromium picolinate supplementation in the diet of Japanese quails raised in a hot climate on performance, lymphoid organ development, intestinal characteristics, and egg quality. A total of 240 quails (Coturnix japonica) were used, distributed in a completely randomized design with five treatments and six replications, containing eight quails per experimental unit. Supplementation with 1.2 mg/kg of chromium picolinate increases egg production rate, weight, egg mass production, and improves lymphoid organ development, but does not bring beneficial effects to the biometrics and morphometry of the intestines of Japanese quails raised in a hot climate. CHAPTER 6: This study aimed to evaluate the influence of chromium picolinate supplementation in the diet of Japanese quails raised in a hot climate on thermoregulatory response, heat loss, physiological parameters, behavior, feathering score, and lesions. A total of 240 quails (Coturnix japonica) were used, distributed in a completely randomized design with five treatments and six replications, with eight quails per experimental unit. Supplementation with 1.2 mg/kg of chromium picolinate in the diet of Japanese quails raised in a hot climate increases thermoregulatory capacity and decreases physiological responses and stress-related behaviors, potentially serving as a tool to mitigate the negative impact of thermal stress.