ISSUE FOCUS 48 FEED & ADDITIVE MAGAZINE September 2023 of the start of exercise (Martinod et al., 2007). In exercising horses, Hsp72 mRNA expression in skeletal muscles has been positively correlated with the peak concentration of blood lactate, indicating the role of Hsp 72 in exercise endurance and the potential for CE to improve resistance to physical stress. These two extremes of aquatic and terrestrial species, suggest the conserved nature of Hsps could extend to the stimulation of a protective response in many other species. Furthermore, a protective cellular response could also lead to improved growth, particularly in livestock species, since less energy might be diverted into mounting immune responses and the impact of disease could perhaps be mitigated. APPLICATION OF CE IN POULTRY Like Artemia, the application of CE to day-old chicks via spray leads to a large increase in Hsps (Hsp72) after 1 hour (Figure 2). Furthermore, Hsp72 remains elevated for at least 24 hours (Parker et al., 2014). To explore the potential performance benefits of CE in broilers, trials were undertaken in Brazil over consecutive months on several different farms. Poultry houses were naturally ventilated, bedding comprised wood shavings and birds fed a corn-soy ration with a nicarbazin/salinomycin anticoccidial shuttle. Over 3 trial periods, birds given CE at day-old via spray were compared to the production average (Control). CE was administered in addition to the standard programme and no other changes made (neither feed nor management were changed to implement cost savings, for example). Different farms were selected each time for CE application. Across all trials, birds administered CE at day-old via spray were on average 6.3% heavier, had a 1% lower mortality and FCR with an associated 9% improvement in EPEF (Table 1). Figure 2. Hsp72 serum levels (via ELISA) in day-old chicks at hatch, 1 hour and 24-hours after CE application Parameter Control CE Duration (days) Total no. of birds placed Liveability (%) Final BW bird (kg) FCR ADG (g/day) EPEF 40.0 828,481 96.1 2.671 1.668 66.71 384 39.7 120,523 97.1 2.838 1.653 71.47 420 Table 1. Field performance (average) of birds sprayed with cactus extract at day-old versus rest of production
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