Multiple Concurrent Stressors in Chicks.

Abstract

Effects of multiple concurrent stressors on Hubbard x Hubbard chicks (Days 10 to 17 posthatch) were studied in a 2(6)-factorial experiment that employed as treatments aerial ammonia (A, 0 or 125 ppm), beak trimming (B, sham handled or beak trimmed/cauterized), coccidiosis (X, gavage with 0 or 6x10(5) sporulated Eimeria acervulina oocysts), intermittent electric shock (E, 0 or between 2.9 and 8.7 mA), heat stress (H, 30.4 or 34.8 C) and continuous noise (N, 80 or 95 dB). All stressors, except noise, decreased weight gain (G), increased coefficient of interindividual variation in gain (CV-G), and decreased feed intake (F) and feed conversion efficiency (G/F). Of a possible 57 interactions, only four were significant for G, two for CV-G, and of a possible 26 interactions, only two were significant for F, none for G/F. As number of simultaneous stressors ("order") increased, G, F, and G/F decreased and CV-G increased, all linearly. Time chicks spent standing was increased by X; time spent eating increased by X; and time spent drinking decreased by H. No effect of order and few stressor interactions were detected for the behaviors. Although behavior results were inconclusive with respect to synergism, antagonism, or additivity of stressors' effects, performance results indicated that chicks responded to each stressor occurred singly or concurrently with up to five others. The results suggest that in practical production situations, where ordinarily poultry experience more than one stressor at the same time, effects of multiple concurrent unrelated stressors on performance may be estimable to a first approximation by summing effects of respective stressors when acting alone.

Ammonia concentration and relative humidity in poultry houses affect the immune response of broilers

“…NH 3 in poultry houses also affects immunological function, reducing specific antibody titers (Caveny et al, 1981) and increasing disease susceptibility (Beker et al, 2004). Moreover, the effects of NH 3 and other simultaneous stressors are generally additive (McFarlane et al, 1989).…”

Domestication effects on behavioural and hormonal responses to acute stress in chickens

“…Some acute events, in addition to physical restraint, have been shown to induce a stress response in chickens, for example heat stress [27][28][29] and unpredictable light regimes [30]. Restraint stress however is a well-established method for triggering a stress response in chickens (see for example [29,31,32] ) where also the HPA-axis recovery has been investigated [31].…”

Early T-maze behaviour and subsequent growth in commercial broiler flocks

“…Because HP chicks showed shorter durations of immobility and less anxiety-related behaviour in this situation than LP birds (Marin et al, 1997a) it is conceivable that they have lower underlying fearfulness. Fear is a potent stressor, growing birds are routinely exposed to a variety of potentially frightening events which frequently depress weight gain (McFarlane et al, 1989), and negative relationships between fearfulness and growth have been reported in domestic chicks and Japanese quail (Mauldin and Siegel, 1979;Bessei, 1984;Gross et al, 1984;Jones, 1996;Jones et al, 1997). Thus, rather than showing a series of acute stress responses to frightening stimuli, with their known catabolic effects (Hemsworth et al, 1994), HP chicks might be more likely to utilise resources for coping with other environmental stressors or for growth.…”

“…It is generally accepted that exposure to multiple and/or chronic stressors can seriously compromise the performance as well as the welfare of poultry (McFarlane et al, 1989;Zulkifli and Siegel, 1995;Jones, 1996). For example, disruption of the social environment or the elicitation of intense or prolonged fear can cause panic-related injuries, pain or death and reduce growth, food conversion efficiency, egg production and product quality (Gross et al, 1984;Mills and Faure, 1990;Gross and Siegel, 1993;Rosales, 1994;Jones, 1996;1997).…”