Performance and immunity of broiler due to addition of citric acid in low nutrient diet

The study was conducted for 35 days to observe the performance and immune status of broiler providing low level of nutrients but using citric acid (CA) as feed additive. Day-old broiler chicks (216) were distributed into 4 dietary groups (6 replicates cages having 9 birds in each) as I,control (22.1% CP and 2961 Kcal ME/kg); 2, low protein+0.5% CA; 3,low energy+0.5% CA; and 4,low protein and energy+0.5%CA. At the end of the trial, broiler chicks of the groups 1, 2, 3 and 4 gained their body weight 1608 +/- 23.03, 1635 +/- 26.41, 1638 +/- 30.21 and 1652 +/- 24.60 g respectively. Total feed intake was highest in low energy diet. Feed conversion ratio (FCR-kg feed intake/kg weight gain) varied among the groups, which was low in group 4. Due to addition of CA, the pH of diets reduced (5.91, 5.20, 5.33 and 5.43 in 1, 2, 3 and 4 respectively) but the changes disappeared in feaces expressing the pH level of 5.66, 5.62, 5.69 and 5.67 respectively. Cost of production per kg live weight of broiler was numerically lower in group 4, where both protein and energy was low and CA was added. In each case, 0.5% CA improved immunity to the broilers of the groups vaccinated against Newcastle disease. Therefore, supplementation of 0.5% CA in low nutrient diet (low protein and low energy) reflected similar weight gain of broiler with further benefits in the elevation of immunity. But further research is needed to find out the limit of lowering the protein and energy in diet by using certain level of CA.