Effeetivity of Mg-Sulphate and Mg Acetate in Alleviating Temperature Stress in The Rex Rabbits

Abstract

Heat stress causes a reduction of Mg-level of cell content, hence the metabolic activities, especially those of carbohydrates-relating reactions. Its consequence is poor growth of animals. An experiment was conducted to study the inclusion Mg-acetate or Mg-sulphate into the diet on the perfomianee of Rex rabbits when the animals were exposed to heat and cold stress. Dietary inclusion of Mg-acetate and Mg-sulphate was 0.17 and 3.0 %, respectively. A control diet [without Mg] was used to compare with. Sixty weanling Rex rabbits [6 week-old] were allocated randomly into 3 dietary treatments within each of four temperature controlled rooms [32°, 26°, 18° and 16°C]. Within each room the rabbits were caged individually. Experiment was carried out for 8 weeks and measurements were made on feed, water and oxygen intake [FL WI and OI], bodyweight gain [BWG], feed conversion [FCR], body temperature [BT], level of plasm-Mg and plasm-thyroxin. Results from the analysis of variance followed by an LSD test indicated that no significant interaction oceured between Mg inclusion with the room temperature on
the measured parameters. Most measured responses were significantly influenced by environmental temperature, but not by dietary Mg-treatment. Increased room temperature [hotter] decreased Fl, BWG, feed effieieney and plasm-thyroxine level. In contrast, WI, OI and BT increased with the increased room temperature. Plasm Mg-level was significantly affected by type of Mg-compound. Inorganic Mg-sulphate increased plasm-Mg level more than did the organic Mg-acetate. There was, however, a tendency that organic Mg [Mg-Acetate] had a more profound effect than the inorganic Mg. Values for intake of feed, water and oxygen, BWG, FCR, BT, plasm-Mg and plasm-thyroxine level varied from 79 to 126 g/rabbit/d, 1821 to 2734 ml/rabbit/ week and 1.29 to 2.64 cc/min/kgO~75, 16 to 24 g/rabbit/d, 4.48 to 5.21, 38.68 to 39.99°C, 31 to 41 mgjl and from 1.55 to 1.89 ug/ml, respectively.