Carcass and meat quality traits of chickens fed diets concurrently supplemented with vitamins C and E under constant heat stress

Abstract

The objective of this study was to determine if a diet supplemented simultaneously with vitamins C and E would alleviate the negative effects of heat stress, applied between 28 and 42 days of age, on performance, carcass and meat quality traits of broiler chickens. A total of 384 male broiler chickens were assigned to a completely randomized design, with a 2 × 3 factorial arrangement (diet with or without vitamin supplementation and two ambient temperatures plus a pair-feeding group) and 16 replicates. Chickens were kept in thermoneutral conditions up to 28 days of age. They were then housed in groups of four per cage, in three environmentally controlled chambers: two thermoneutral (22.5 and 22.6°C) and one for heat stress (32°C). Half the chickens were fed a diet supplemented with vitamins C (257 to 288 mg/kg) and E (93 to 109 mg/kg). In the thermoneutral chambers, half of the chickens were pair-fed to heat stressed chickens, receiving each day the average feed intake recorded in the heat stress chamber in the previous day. Meat physical quality analyses were performed on the pectoralis major muscle. No ambient temperature × diet supplementation interaction effects were detected on performance, carcass, or meat quality traits. The supplemented diet resulted in lower growth performance, attributed either to a carry-over effect of the lower initial BW, or to a possible catabolic effect of vitamins C and E when supplemented simultaneously at high levels. Heat stress reduced slaughter and carcass weights, average daily gain and feed intake, and increased feed conversion. Growth performance of pair-fed chickens was similar to that of heat stressed chickens. Exposure to heat stress increased carcass and abdominal fat percentages, but reduced breast, liver and heart percentages. Pair-fed chickens showed the lowest fat percentage and their breast percentage was similar to controls. Heat stress increased meat pH and negatively affected meat color and cooking loss. In pair-fed chickens, meat color was similar to the heat stressed group. Shear force was not influenced by heat stress, but pair-fed chickens showed the tenderest meat. In conclusion, reduction in growth performance and negative changes in meat color in heat stressed chickens were attributed to depression in feed intake, whereas negative changes in body composition, higher meat pH and cooking loss were credited to high ambient temperature per se. Diet supplementation with vitamins C and E as antioxidants did not mitigate any of these negative effects.

Effect of dietary supplementation with <i>Rhizopus oryzae</i> or <i>Chrysonilia crassa</i> on growth performance, blood profile, intestinal microbial population, and carcass traits in broilers exposed to heat stress

“…Moreover, Hosseini-Vashan et al (2016) reported no effect of HS on the abdominal fat content of broilers. Nevertheless, our data were in contrast to Zeferino et al (2016), who showed negative effects of HS on the carcass composition and meat quality in broilers. The exact reason for the lack influence of HS on carcass traits in broilers is unclear, but the acclimatization of birds to chronic HS seemed to improve their heat tolerance (Al-Fataftah and AbuDieyeh, 2007), resulting in less alteration of metabolism and thus carcass composition.…”

“…In this study, HS was associated with the reduced weight of active organs such as heart and intestine. This result was similar to that reported by Sohail et al (2013) and Zeferino et al (2016). Apart from the physiological adjustment derived from depressed feed intake (Zeferino et al, 2016), the increased corticosterone level in HS broilers may be responsible for the lower percentage of the organs (Hu et al, 2010).…”

“…This result was similar to that reported by Sohail et al (2013) and Zeferino et al (2016). Apart from the physiological adjustment derived from depressed feed intake (Zeferino et al, 2016), the increased corticosterone level in HS broilers may be responsible for the lower percentage of the organs (Hu et al, 2010). Corticosterone may decrease glucose transport to a variety of tissues/organs, resulting in tissue regression and weight loss (Yang et al, 2015).…”

“…A recent study has revealed the detrimental effects of HS on physiology, immunology and microbiology resulting in abnormalities and impaired performances in birds (Sugiharto et al, 2016a). HS also decreases carcass yield and increases fat content in broiler chicks (Zeferino et al, 2016).…”

Effects of dietary vitamin E (DL-α-tocopheryl acetate) and vitamin C combination on piglets oxidative status and immune response at weaning

“…However, that study was not carried out in stressful conditions. In contrast, Zeferino et al (2016) in the study on chickens found that diet supplementation with vitamins C and E as antioxidants did not mitigate any of the negative effects occurring under heat stress.…”