THE EFFECTS OF ASCORBIC ACID, PROTEIN AND ENERGY LEVELS ON THE PERFORMANCE OF HEAT STRESSED LAYING CHICKENS

THE EFFECTS OF ASCORBIC ACID, PROTEIN AND ENERGY LEVELS ON THE PERFORMANCE OF HEAT STRESSED LAYING CHICKENS

Abstract:

A study involving three feeding trials was conducted in an attempt to design a hot season feeding proframme for laying birds in the tropics. The first trial involved 162 29-week old hens in a 3 x 3 factorial design made up of cross-classified combinations of three dietary protein (18, 16 and 14% CP) and three energy levels (2800, 2600 and 2400kcals ME/ Kg feed). The experiment was conducted to determine the optimal protein: energy combinations to be fed during the hot months. Each of the nine treatments was replicated three times. The average maximum indoor temperature was 37.19 C for the study period. Diets 9 (14% CP and 2400 Kcal ME/kg feed), 5 (16% CP and 2600 Kcal ME/kg Feed) and 7 (14% CP and 2800 Kcal ME/kg feed) gave better egg production with improved feed conversion ratios while egg quality was maintained. For experiments 2 and 3, four isonitrogenous and isocaloric dietary treatments were involved. Each trial had three replicates per treatment and used seventy-two 33-week old hens. In Experiment 2, ascorbic acid (AsA) was supplemented at 0, 200, 400 and 600mg/kg feed to determine if, and the optimal level at which AsA moderated heat stress in laying hens. Ascorbic acid supplementation improved egg production feed intake and utilization and cost of feed/Kg egg, A supplemental level of 400mg AsA/ Kg diet gave the most efficient response. In Experiment 3, diet 1 served as control, diet 2 contained 200mg AsA/Kg diet, diet 3 contained 5% palm oil while diet 4 had both 200mg AsA/Kg feed and 5% palm oil supplementation. The objective was to determine the effect of oil alone and in combination with ascorbic acid on heat stressed laying chickens. The diet containing 5% palm oil alone improved egg production, egg weight, feed intake, daily protein and energy intakes and feed/kg eggs. It also reduced incidence of cracked eggs and mortality. Supplementation of 200mg AA/Kg diet and 5% palm oil effected a synergistic response which improved hen-day egg production, egg weight, shell thickness, feed/Kg eggs, final body weight while reducing the number of cracked eggs. It is concluded that heat stressed laying chickens should be fed low energy, low protein diets (14% CP, 2400 Kcal ME/Kg diet, 16% CP, 26C0 Kcals ME/Kg) capable of ensuring adequate energy intake, diets containing 400mg ascorbic acid/Kg or a combination of supplemental ascorbic acid (200mg/Kg diet) plut 5% palm oil.

THE EFFECTS OF ASCORBIC ACID, PROTEIN AND ENERGY LEVELS ON THE PERFORMANCE OF HEAT STRESSED LAYING CHICKENS

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