Productive, physiological and immunological responses of two broiler strains fed different dietary regimens and exposed to heat stress

Abstract

The impact of dietary regimens on productive traits, meat quality, physiological adoption, immunological response and digestibility of nutrients was studied using Ross-308 and Cobb-500 strains. Chickens were reared under normal brooding conditions during most of the experimental period, but exposed to heat stress [(HS) of age, the SPD group was fed 20% CP with 13.42 MJ/kg, the HPD group was fed 22% CP with 13.42 MJ/kg, and the HPMED group was fed 22% CP with 14.06 MJ/kg. Each group within each strain was replicated six times with five chicken males each. For the whole experimental period, Ross and Cobb chickens fed the HPMED showed higher BWG than chickens on the HPD. Broilers fed the HPMED had improved FCR compared to those on the SPD, independent of broiler strain. Further, independent of broiler strain, the HPMED regimen increased the dry matter, protein, and lipid contents of meat compared to the other regimens, and decreased cloacal temperature, respiration rate and Heterophile/lymphocyte (H/L ratio) compared to the HPD regimen. Growth and feed utilisation, percentage thymus, protein in meat were improved of Ross compared to Cobb, but abdominal fat, meat lipid and pH were decreased. On the other hand, Cobb on HPD had lower cloacal temperature and respiration rate than Ross strain, suggesting that production, physiology and immunological response of broiler chickens depend on feeding regimen that should be specific for each strain. ARTICLE HISTORY

Effects of Fennel Seed Powder Supplementation on Growth Performance, Carcass Characteristics, Meat Quality, and Economic Efficiency of Broilers under Thermoneutral and Chronic Heat Stress Conditions

“…The color of meat is correlated with myoglobin and hemoglobin concentrations and their status [40,41]. The current results are in agreement with the results reported by [3,42]. The highest value of a* was reported in the 1.6% FSP group under normal temperatures.…”

“…The main effect of the temperature on broiler performance was significant and confirmed the success of heat stress induction. The adaptation to heat stress markedly influences broiler performance, production index, and economic efficiency [3,13,35]. Broilers at market weight generate approximately 5-10 kcals of energy per hour as a normal physiological process [9].…”

“…However, diets with fennel powder of 1, 2, and 3 g/kg resulted in significant improvements in broiler growth and FCR, while feed intake was unaffected [28]. Heat stress may cause a physiological dysfunction that triggers the body to utilize nutrients to synthesize critical proteins instead of using them for growth, which allows broilers to decrease against the oxidative damage of heat stress [2,3,37].…”

Effects of dietary supplemented of γ-amino butyric acid on growth performance, blood biochemical indices and intestinal morphology of yellow-feathered broilers exposed to a high temperature environment

“…High temperature is a major problem in tropical and subtropical regions, often resulting in heavy economic losses in poultry production (Nardone et al 2010;Attia and Hassan 2017;Attia et al 2018). Perhaps because it is widely distributed in the central nervous system, GABA appears to be a new treatment for improving performance during heat stress.…”

“…Meanwhile, nutritional manipulation is a convenient and feasible approach to alleviate these negative impact caused by high temperature environments (Chand et al 2014;Dhama et al 2015). For example, broilers were fed a high-protein diet and high-metabolisable energy (ME) diet could increase growth performance, immune function and meet quality of Ross-308 and Cobb-500 broilers exposed to heat stress (Attia et al 2018). They also found that increasing protein with energy concentration may be a useful tool in improving the productive performance, meat quality, blood haematological and biochemical traits, antioxidants and immunity of broiler chickens exposed to heat stress (Attia and Hassan 2017).…”