Performance and carbon turnover in fast- and slow-growing broilers submitted to cyclic heat stress and fed on high-protein diets

Abstract

Two experiments were conducted to test the hypothesis that when using similar protein/amino acid diets and environment temperature conditions, the performance and carbon turnover in muscle and liver tissues, as measured by the incorporation of stable isotopes ((13)C/(12)C), must be different between fast-growing Cobb 500® and slow-growing Label Rouge broilers. For both experiments (Cobb and Label Rouge), 21-d-old birds were distributed in a completely randomised, 3 × 3 factorial design; three environmental temperatures (cyclic heat stress ad libitum, 22°C ad libitum, and 22°C restricted) and three crude protein concentrations (189.1, 210 and 220 g/kg CP) were used. The Cobb 500® had better performance with higher concentrations of crude protein. Cyclic heat stress (a temperature factor), negatively affected this genetic strain's performance. For the Label Rouge birds, the crude protein concentrations in the diet presented inconsistent results and cyclic heat stress did not affect the performance. The carbon turnover rate was affected in the Cobb 500® strain, with a high protein content reducing carbon turnover in the evaluated tissues (liver and muscles). Feed intake had a greater impact on carbon turnover rates than cyclic heat stress. The Label Rouge birds were not affected by the evaluated factors, suggesting that genetic improvement has a leading role on tissue carbon turnover. There is a genetic influence on carbon turnover in the liver and muscle tissues of broiler chickens. In addition, genetically fast-growing broilers are more susceptible to variations in diet composition and environmental temperature than less rapidly growing animals.

Field Interventions Against Colonization of Broilers by Campylobacter

“…Small‐scale trials mimicking cyclical heat stress (generally 31 °C and above) on birds in the later stages of rearing have demonstrated reduced production performance accompanied by elevated corticosterone plus immunosuppressive phenomena (Al‐Ghamdi, ; Campos et al., ; Lara & Rostagno, ; Park et al., ; Quinteiro‐Filho et al., , ; Rimoldi et al., ; Verbrugghe et al., ). Effects of heat stress on the gut, in particular, are indicated by evidence of mild enteritis (Quinteiro‐Filho et al., , ) and altered intestinal morphology in experimentally stressed birds (Burkholder, Thompson, Einstein, Applegate, & Patterson, ; Lara & Rostagno, ).…”

Testing for effects of growth rate on isotope trophic discrimination factors and evaluating the performance of Bayesian stable isotope mixing models experimentally: A moment of truth?

“…Although broiler chickens have undergone extensive artificial selection for growth in captivity, variation in growth rate remains [32]. To our knowledge, although the effects of individual growth rates on TDFs have been demonstrated in fish species, similar evaluations have not been conducted in endotherms with higher basal metabolic rates, like birds [33,34], but see [35]. Because variation in tissue isotopic values related to environmental factors and dietary composition (isotopic values and source of macronutrients) is minimized in our captive setting, the broiler chicks are an ideal system to test how variation in growth and other organism-dependent factors, such as tissue type, affect TDFs and how accurately BSIMMs allocate individual birds to assigned dietary groups when model inputs vary.…”

The Low Expression of DUSP1 and HSPA5 Inhibits Chicken Immune Response and Causes Decreased Immunity under Heat Stress

“…Under high temperatures in summer, poultry would experience a host of health problems, such as reduced immunity and disease resistance, lower food intake, slow growth and development, abnormal endocrine functions, and increased mortality [1][2][3]. These issues seriously hamper intensive poultry production, leading to economic losses.…”