Effect of heat and several additives related to stress levels on fluctuating asymmetry, heterophil:lymphocyte ratio, and tonic immobility duration in White Leghorn chicks

Abstract

The purpose of this study was to analyze the effects of heat and several additives related to stress on fluctuating asymmetry (groups 1 to 10), heterophil:lymphocyte ratio (groups 1 to 3 and 8 to 10), and tonic immobility duration (groups 1 to 7 and 10) in White Leghorn chicks at 42 d of age. Chicks in group 1 (heat) were reared with temperatures 8°C greater than those of the control group. Groups 2 to 9 consisted of chicks reared with temperatures 8°C greater than those of the control group and addition of capsaicin, allicin, ascorbic acid, tryptophan, brewer's yeast, lactic acid, corticosterone, or cholesterol in diet. Chicks in group 10 (control) were reared with standard temperatures. Heat effect was significant (P<0.05) for the heterophil:lymphocyte ratio, which was greater in heat-stressed chicks without any additives and smaller in control chicks. There were no significant differences for the fluctuating asymmetry and the tonic immobility duration between both groups. Heterophil:lymphocyte ratio for heat-stressed chicks with capsaicin or allicin was significantly lower (P<0.05) than that of heat-stressed chicks without any additives. Capsaicin effect was not significant for the fluctuating asymmetry and the tonic immobility duration, whereas allicin significantly increased fluctuating asymmetry of wing length and tonic immobility duration (P<0.05). The addition of lactic acid or corticosterone resulted in greater fluctuating asymmetry of wing length of heat-stressed chicks (P<0.05). In conclusion, an increased heterophil:lymphocyte ratio was found in heat-stressed chicks without additives, indicating that it is a more reliable indicator of the effect of heat in chicks. In addition, dietary capsaicin or allicin supplementation was effective to alleviate the stress induced by the high temperature, as indicated by a lower heterophil:lymphocyte ratio.

The welfare of slow growing broiler genotypes reared in organic system

“…In the present study TI of slow-growing broilers had excessively lower (ranged 57.70 to 93.77 s) with outdoor access than those (ranged 158 to 398 s) of Campo et al (2008), who tested six different Spanish breeds. Likewise, Prieto and Campo (2010) stated that TI found 99 s in White Leghorn reared with standard temperatures.…”

Heat Stress and Gut Health in Broilers: Role of Tight Junction Proteins

“…Poultry, in particular, appears to be very heat sensitive animals, due to lack of sweat glands and high metabolic activity. 4,5 It is estimated that heat stress alone costs the U.S. poultry industry more than 100 million dollars a year and this number is expected to rise. 6 For broiler (meat-type) chickens, the external temperature for optimal performance is 18 to 22 ºC.…”

Image analysis for assessing broiler breeder behavior response to thermal environment

“…For this experiment the video image were processed using the filter Blob Explorer, which enhances bird in contrast to its adjacent area. Behavioral observations were done using two ranges of different controlled temperatures inside the environmental chamber a) ≤ 29 °C, and b) > 29 °C (PRIETO & CAMPO, 2010). Due to the environmental chamber thermal inertia the registered temperatures with a variation of 1.0 °C were accepted during the trial.…”

“…Heat stress directly affects breeders' productivity and, in addition, may expose them to high mortality, and reduce live production performance for various genetic strains (PRIETO & CAMPO, 2010). Adult female breeders reared in temperature around 24 ± 5 ºC (so-called thermal neutral zone) tend to produce more and present appropriate welfare status (FRANCO-JIMENEZ et al, 2007).…”