Alleviation of Chronic Heat Stress in Broilers by Dietary Supplementation of Novel Feed Additive Combinations

Abstract

Heat stress causes economic losses via decreasing feed intake, nutrient digestion, weight gain, feed conversion, immunity, carcass quality and increasing mortality in broilers. The aim of the study was to assess the ability of dietary additive combinations to ameliorate the detrimental effect caused by chronic heat stress (32 ± 2ºC for 24 h per d) on performance, carcass traits, metabolic status and economic efficiency of broiler chickens. A total of 420, one-day old Cobb-500 broiler chicks were assigned into seven treatment groups (n=60) of five replicates. Each replicate contained 12 unsexed chicks. The control groups did not receive any supplementation to the basal diet (thermoneutral control (TNC) and heat stress control (HSC) groups). The other groups received control diet supplemented with 1 % cumin plus 1 % turmeric powders (T1); 1.5 g/kg potassium chloride plus 2 g/kg sodium bicarbonate (T2); 1000 ppm propolis plus 15000 IU vitamin A (T3); 1200 ppb chromium plus 500 ppm vitamin C (T4) ; 1200 ppm betaine plus 500 ppm vitamin E (T5). The results indicated that at 42 d of age, all dietary additive combinations improved the growth performance indices, carcass traits, concentrations of serum antioxidant enzyme biomarkers, stress biomarkers and economic efficiency in comparison to HSC group. Based on the obtained results, it could be concluded that dietary supplementation with betaine and vitamin E followed by chromium and vitamin C combinations offers a good management practice for alleviating heat stress related depression in the performance of broiler chickens.

Impacts of Strain Variation on Response to Heat Stress and Boldo Extract Supplementation to Broiler Chickens

“…Water intake was not significantly altered by the interaction among broiler strain × heat stress × boldo treatments with an increase in water consumption by heat-stressed birds of both strains. Our results are consistent with those of previous studies [30][31][32]. The adverse effect of HS on broiler growth performance can be attributed to the mucosal epithelial damage caused by HS that impairs nutrients absorption.…”

“…Previous investigations attributed the alterations in profitability in broiler production to the variations in growth rate and the cost of one-day-old chicks, drugs, labor, feed, veterinary services, and the sale price of birds [75,76]. Our results are consistent with those reported in earlier studies [32,77,78].…”

“…The authors attributed this reduction in muscle weight to the elevation of protein synthesis susceptibility than to proteolysis at 32 • C, which thereby lowered the deposition of muscle protein. The amelioration effects of FA on carcass traits of heat-stressed birds have been reported [32,[46][47][48]. Possible explanations for the heat stress mitigation effect of FA may be their ability to boost the antioxidant defense system, immune response, digestive enzyme secretion as well as stimulate the appetite and feed intake [32,49].…”

“…The amelioration effects of FA on carcass traits of heat-stressed birds have been reported [32,[46][47][48]. Possible explanations for the heat stress mitigation effect of FA may be their ability to boost the antioxidant defense system, immune response, digestive enzyme secretion as well as stimulate the appetite and feed intake [32,49]. Moreover, the effects of heat exposure on abdominal fat have been controversial among researchers for a long time.…”

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“…Ibrahim et al, observed that total blood lipid was significantly lowered in dietary Cr supplemented 14 . Al-Sultan et al reported Cr supplementation increased the serum concentration of calcium, phosphorous, and potassium and decreased the level of sodium 15 . Amatya et al found that Cu, Zn, Fe, and Mn retention was better when Cr was supplemented in the feed of broilers 16 .…”