Effects of Heat Stress on Growth Performance, Carcass Traits, Physiological Components, and Biochemical Parameters in Local Algerian Growing Rabbits

Abstract

Heat stress is a detrimental factor affecting the welfare of all livestock, especially rabbits, as they are sensitive to high temperatures. The current study investigated the effect of high ambient temperature on growth performance, slaughter traits, physiological indicators, and some hematological and biochemical parameters in Algerian local growing rabbits. A total of 48 local rabbits of both sexes (35 days old) were allotted into two groups (24 per group). The control group rabbits were exposed to an ambient temperature and humidity, averaging 21.8 ± 1.3°C and 51.7 ± 3.6%, respectively. Rabbits in the heat stress group were subjected to a warm ambient temperature and humidity of 30.5 ± 1.82°C and 65.5 ± 7.2%, respectively. The growth performance was measured and calculated from 35 to 91 days of age. Physiological indicators (rectal, skin, and ear temperatures, respiratory, and heart rates) were examined at 88 days of age. The carcass traits, blood metabolites, and hematological parameters of rabbits were measured and calculated at slaughter (92 days of age). The obtained results indicated a decrease in body weight, daily gain, and daily feed intake of rabbits in heat stress rabbits, compared to the control group. However, feed conversion ratio was significantly higher in the heat stress group, compared to the control. Heat stress group rabbits showed significantly higher blood metabolite levels, except the glycemia, which was similar in both groups. No significant effect of heat stress was found on the carcass yield, anterior, posterior, and intermediate parts of the carcass. However, the yield of the other components of the carcass (liver, kidney, peritoneal and inter-scapular fat) was significantly lower in the heat stress group. In the heat stress group, rectal, skin, and ear temperatures as well as heart and respiratory rates, were significantly higher than those of the control group. In the present experimental conditions, exposure of local rabbits to chronic heat stress could induce some changes to biological, physiological, and biochemical parameters leading to altered growth performance.