Transport stress in broilers: I. Blood metabolism, glycolytic potential, and meat quality

Abstract

The effect of transport stress on blood metabolism, glycolytic potential, and meat quality in broilers was investigated. Arbor Acres chicks (n = 360, 1 d old, males) were randomly allotted to 1 of 5 treatments: unstressed control, 45-min (short-term) transport with 45-min (short-term) recovery, 45-min transport with 3-h (long-term) recovery; 3 h (long-term) transport with 45-min recovery, and 3-h transport with 3-h recovery. Each treatment consisted of 6 replicates with 12 birds each. On d 46, all birds (except the control group) were transported according to a designed protocol. Transport time affected plasma glucose level (P<0.05) and glycogen level (P=0.06) in breast muscle as well as the area (P<0.01) and density (P<0.01) of IIa fibers. Glucose concentration increased slightly during the first 45 min of transport and then decreased dramatically in the long-term transported broilers (P<0.05). Long-term transport decreased the concentration of breast glycogen (P=0.06) and affected the size of IIa fibers in tibialis anterior by decreasing the area (P<0.01) with an increase in density (P<0.01). However, a long-term recovery after transport contributed to the homeostasis of blood corticosterone (CORT, P=0.05) and low levels of glycogen (P<0.05), lactate (P<0.01), and glycolytic potential (P<0.01) in thigh muscles. Interactions existed between transport and recovery time on area (P<0.05) and density (P<0.01) of IIa fibers. Furthermore, plasma nonesterified fatty acids increased significantly in the 3-h transport with 3-h recovery group (P<0.05) in comparison with the control. These results suggested that transport induced the release of plasma CORT and glycopenia, which affected the contractive status of muscle fibers by changing their area and density, and enhanced glycolysis and even lipolysis. A long-term recovery after transport was beneficial in lowering plasma CORT levels and reducing muscle glycolysis, which might improve broiler meat quality.

Effects of dietary supplementation with creatine monohydrate during the finishing period on growth performance, carcass traits, meat quality and muscle glycolytic potential of broilers subjected to transport stress

“…• Control: the broilers fed the basic grower diet and experienced 0.75-h transport, as a lower stress group (Zhang et al, 2009;Yue et al, 2010); • T: the broilers fed the basic grower diet and experienced 3-h transport; • T + CMH 600 : the broilers fed the basic grower diet supplementation with 600 mg/kg CMH from 28 to 42 days of age and experienced 3-h transport; • T + CMH 1200 : the broilers fed the basic grower diet supplementation with 1200 mg/kg CMH from 28 to 42 days of age and experienced 3-h transport.…”

“…Meanwhile, samples (~5.0 g each) from the left pectoralis major (breast) and tibialis anterior (thigh) muscle were quickly frozen in liquid nitrogen and stored at − 80°C until analysis of muscle lactate, glycogen and GP. These two kinds of muscles were selected because they have different muscle fiber distribution pattern (Dubowitz, 1985;Zhang et al, 2009). The right side breast and thigh muscle were taken to measure meat quality traits.…”

“…Each sample was measured three times and their average value was taken as the final result. The pH decline within 24 h postmortem (ΔpH) was calculated as ΔpH = pHu − pH 45 min (Zhang et al, 2009).…”

“…Muscle GP analysis Muscle lactate and glycogen content were determined, modified from the methods of Hambrecht et al (2005) and Zhang et al (2009). The frozen muscle (0.5 g) was homogenized for 1 min in 4.5 ml ice cold saline and then centrifuged for 10 min at 2700 × g at 4°C.…”

“…Long duration transportation has been reported to result in physiological and metabolic changes (Yue et al, 2010;Zhang et al, 2009) and that can affect animal welfare, processing yield and meat quality (Owens and Sams, 2000;Dadgar et al, 2010;Petracci et al, 2010). More importantly, transport stress also causes higher chicken mortality, live weight loss and poor meat quality, which results in substantial economic losses to the poultry industry (Bianchi et al, 2005;Karaman, 2009;Chauvin et al, 2011).…”