Energy and nitrogen metabolism of diseased chickens: aflatoxicosis

Mathematical model for energy and protein balance simulation in broilers

The authors used the empirical equations of mathematical modelling for the energy and protein balance simulation, with the view of calculating the body weight gain in broilers fed various diets. The results found by using the model were compared with the experimental data obtained by several authors. A standard deviation of +/- 1.20% and a mean error of +/- 0.28% and a mean error of +/- 0.28% which proved that the model average was a sufficient estimate of the experimental average were found. Furthermore, using the regression method, a significant correlation of variables was evidentiated.

A comparison of the energy and nitrogen metabolism of starved ducklings and chickens

1. Respiration chambers were used to measure, over 24 h, the heat production of groups of starved ducklings from two batches and of starved broiler chickens from one batch up to 28 and 39 d of age, respectively. Duration of starvation prior to measurements and ambient temperature were adjusted according to the age of the birds. 2. Respiratory quotient of 0.705 for chickens was significantly lower than that of 0.713 for ducklings. 3. Starvation heat production (kJ/d) of ducklings was 804 kgW0-70 compared with 675 kgW0-74 for chickens. There were differences in heat production between the two batches of ducklings used when expressed per kg body weight (W). 4. Ducklings lost more body weight, body fat and protein than chickens during starvation. Gaseous ammonia-N was on average 9% of N excreted by ducklings and 4% of N excreted by chickens.

The effect of exercise on the toxicity of aflatoxin B1 in chickens

Three trials were conducted to study the effects of exercise on aflatoxicosis in young broiler and layer chicks. Aflatoxin B1 was fed at levels of 0 or 5 ppm in a corn-based diet. Exercise was conducted on a motorized treadmill. In one trial, the growth rate of aflatoxin-fed birds was found to be increased significantly (P less than .05) by exercise, but it was not equal to that of the control birds. In other trials, growth rates were increased by exercise in birds receiving aflatoxin, but not significantly. Feed consumption measurements indicated that the decreased growth rates in the aflatoxin-fed birds were due to decreased feed consumption. Glucose-6-phosphate dehydrogenase levels were decreased significantly in the unexercised broiler chicks fed aflatoxin (P less than .025). In one trial, liver weights of broiler chicks were increased significantly by aflatoxin (P less than .005). In the birds fed aflatoxin and exercised, liver weights also were increased but to a lesser degree (P less than .01).

Energy and nitrogen metabolism of chickens infected with either Eimeria acervulina or Eimeria tenella

1. The effects of sublethal infections of E. acervulina and E. tenella on the energy and nitrogen metabolism of groups of five broilers aged 16 d were studied for 16 d in respiration chambers. 2. The metabolisable energy content of the diet for chickens infected with E. acervulina was 0.689 of its gross energy content and N retention was 42.5 g/100 g N intake compared with 0.738 and 47.1 g respectively, in uninfected pair-fed controls. Chickens infected with E. tenella were similarly affected. 3. Efficiency of utilisation of ME by chickens infected with E. acervulina was 0.43 during the first 8 d after infection, and 0.52 during the second 8 d compared with an overall efficiency by non-infected chickens fed ad libitum of 0.73. Maintenance energy requirement of infected chickens was higher during the first 8 d after infection than during the second 8-d period. 4. Body composition measurements showed that of the total gain in weight of chickens infected with E. acervulina, only 7.5 g/kg gain was fat and 213 g/kg was protein compared with 45 g and 210 g respectively for non infected chickens fed ad libitum. 5. E. acervulina and E. tenella infections reduced the apparent digestibility of total mineral, calcium and phosphorus.