Authors: ZORAN RUZIC, ZDENKO KANACKI, MARIJA JOKANOVIC, SUZANA VIDAKOVIC, SLOBODAN KNEZEVIC, SLAVOLJUB JOVIC, SMILJANA PARAS
Abstract: Heat stress (HS) is one of the greatest problems in contemporary chicken production and it entails significant economic losses. The purpose of this paper is to examine the influence of early-age thermal conditioning (ETC), vitamin C (Vit C) supplementation, and their combination on the production characteristics and specific quality parameters of the meat of broilers which were exposed to chronic HS in the last two weeks of breeding. Four hundred broilers (Cobb 500) of both sexes were divided into 4 experimental groups. Group C was given Vit C (2 g/L) dissolved in water from day 22 until the end of production. Group T was exposed to ETC for a period of 24 h at the temperature of 38 ± 1 ºC and 40%-60% relative humidity on the fifth day of breeding. Group TC was the combination of the groups T and C, while group K was the control group. The results indicate that ETC, independently or in combination with Vit C, improves the production characteristics in terms of feed conversion reduction (P < 0.05). The examined treatments increase the volume (P < 0.05) of certain parts of the body (carcass, legs and thighs, and back) with regards to total body weight, especially in group TC. Regarding meat quality determined according to pH value and meat color criteria (CIEL*), the best results were also observed in group TC, followed by groups T and C. These results justify the use of Vit C and ETC in summer conditions, when heat stress is expected; however, the best results can be achieved by combining these two methods, thus producing a synergistic effect.
Keywords: Broiler production, heat stress, meat quality, thermal conditioning, vitamin C
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