Effect of age and cyclical heat stress on the serum biochemical profile of broiler chickens

Abstract

This study aimed to evaluate the influence of age and cyclical heat stress for 1 hour per day on the levels of serum proteins, metabolites, and enzymes in broiler chickens of 21-42 days of age. We used 420 male broiler chickens, Cobb Avian48TM breed, in a completely randomized experimental design, composed of two treatments and six replicates. The treatments consisted of two thermal environments: one in which broiler chickens were raised under natural conditions of temperature and humidity for the first 42 days of age (control) and another in which chickens were subjected to heat stress at 36°C, from days 16 to 42, for 1 hour per day (1200-1300 hours). At 21, 28, 35, and 42 days of age, approximately 5 mL of blood was collected by cardiac puncture in two birds per replicate. In each serum sample, levels of total protein, albumin, globulin, albumin:globulin ratio, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyltransferase (GGT) activity and uric acid, creatinine, total cholesterol, triglycerides, high-density lipoproteins (HDL), very low density lipoproteins (VLDL), low-density lipoproteins (LDL), and glucose levels were determined. Concerning the environment and the age, no significant differences in the levels of glucose, uric acid, ALT, triglycerides, and very low density lipoproteins were observed. There was a significant interaction between the environment and the age for cholesterol and LDL values. At 21 days of age, cholesterol and LDL-cholesterol (LDL-C) were higher in birds under stress than in the control treatment birds, which did not occur in other age groups. Aspartate aminotransferase activity was higher in chickens under cyclical heat stress than in chickens subjected to control treatment and displayed a cubic response regarding the environment. The age of the birds influenced the values of total protein, albumin, globulin, albumin:globulin (A:G) ratio, creatinine, GGT, and HDL. In conclusion, cyclical heat stress, at 36ºC, for one hour, from days 16 to 42 of age increases serum AST, whereas cholesterol and LDL-C levels increase only at day 21, indicating that birds may have adapted to heat stress. Age influenced the activity of AST and GGT and levels of creatinine, total protein, albumin, globulin, A:G ratio, cholesterol, HDL-C, and LDL-C. Key words: Poultry. Cholesterol. Liver enzymes. Glucose. ResumoObjetivou-se avaliar a influência da idade e do estresse cíclico por calor durante uma hora por dia, nas concentrações das proteínas, metabólitos e enzimas séricas em frangos de corte de 21 a 42 dias de idade. Foram utilizados 420 pintos de corte machos, da linhagem Cobb Avian48 TM , em um delineamento inteiramente casualizado, composto de dois tratamentos e seis repetições. Os tratamentos foram constituídos de dois ambientes térmicos: um para frangos de corte criados em condições naturais de temperatura e umidade do primeiro ao 42° dia de idade (controle); e outro para estressados por calor à 36 °C do 16° ao 42° dia, durante uma hora do dia (12h00m às 13...

Physiological response, endrocrine and performance of broilers under cyclic heat stress

“…This was not observed in the present study, possibly because the broilers recovered from the effects of stress during the warmest part of the day. This adaptation response of broilers to cyclic heat stress was also discussed by Bueno et al (2017) and Balnave (2004), who observed a compensatory gain (in performance or in physiology) of broilers during periods when temperature draws near to thermal comfort, most often at nighttime.…”

“…found that albumin is the main carrier protein of thyroidal hormones. Based on the albumin levels found by Bueno et al (2017) in a study that used broilers exposed to cyclic heat stress, the highest levels of albumin are observed in broilers on days 28 and 42 of age. This means that it is possible that T was efficiently converted into T 3 on day 28, when metabolism is high, since the concentration of T 4 was the lowest and T 3 levels were still high.…”

Bone parameters and organ morphometry of two broiler chicken lines exposed to heat for different periods

“…Heat stress and the lines did not influence small intestine morphometry (Table 3). In the present study, heat stress was cyclic (one to three daily hours under high temperatures and 23 to 21 h under ideal temperatures); thus, the finding that small intestine morphometry was not changed by heat can be partly explained by the compensation occurring at nighttime and in the other moments when the birds were under ideal temperatures (BALNAVE, 2004;BUENO et al, 2017). As regards the line, a possible explanation for the lack of effects is that body weight did not differ between the two (Table 4).…”

“…A presumed interpretation for the lack of differences in density and mineral matter of the tibia between the thermal environments is the fact that mineral deposition in the bird skeleton is more intense in the initial weeks; i.e., until 21 days of age (OLIVEIRA et al, 2014); thus, the seven days of exposure to high temperatures (14 to 21 days of age) were not sufficient to cause alterations in mineral matter and density, in relation to the 14 days the birds remained under comfort. Moreover, the intensity and duration of heat stress were not sufficient to affect mineral deposition in the tibia, since the birds managed to recover from the stress they had undergone during the fresher times of the day (BALNAVE, 2004;BUENO et al, 2017).…”

Effect of acute heat stress on the physiological and reproductive parameters of broiler breeder hens – A study under controlled thermal stress

“…Cholesterol level in heat treated birds was higher than that of control on the 3 rd day (+8.38%), but on the 10 th day, it was +20% (P<0.05). Sohail et al (2010), Xie et al (2015) and Rodrigues Bueno et al (2017) also reported similar cholesterol level in broilers under heat stress. Serum calcium and phosphorus of the treatment group were showing significantly lower values (P<0.05).…”