Effect of selenium and Ascaridia galli infection on antioxidant biomarkers in broiler chickens: a mathematical model for parasite reduction and host growth.

The activity of selenium-dependent glutathione peroxidase (GPX), liver concentration of vitamin E, and plasma and liver selenium levels were used for estimation of the antioxidant status of broiler chickens infected with Ascaridia galli. These biomarkers were recorded in an experiment covering 70 days p.i. At the same time the establishment rate of A. galli in chicken intestines, gain in the host body weight and chicken survival were studied. Broiler chickens (Cobb hybrids) were infected with 1450 embryonated A. galli eggs and treated with Sel-plex. A mathematical model was applied to determine the rate of nematode reduction and the relative rate of gain of host body weight, which are essential kinetic parameters of parasite-host interaction. The activity of GPX increased with both elevated selenium and reduced infection levels. The concentrations of selenium and vitamin E, and the GPX activity in the infected chickens demonstrated a similar pattern of change with time after day 30 p.i. The supplementation of the broilers with dietary selenium in the form of Sel-plex improved their antioxidant status. Increases by 29% in vitamin E concentration, 15% in GPX activity, and 22% in liver selenium concentration, respectively, were recorded in the infected and treated, compared to infected and untreated broilers.

Administration of Zn-Co-Mn basic salt to chickens with ascaridiosis. II. Sex ratio and microelement levels in Ascaridia galli and in treated and untreated chickens.

Hisex chickens were infected with 1,450 embryonated Ascaridia galli eggs and treated with a new synthesized basic mixed salt (Zn(x)Co(y)Mn(1-x-y)) x (OH)6SO4 x 2H2O). The worm burden was determined and sex ratios for A. galli of M:F = 1.4 and M:F = 2 in untreated and treated chickens, respectively, were found. A decrease in the mean establishment rate of A. galli in treated chickens was observed. The levels of zinc, cobalt and manganese were determined in liver and muscle of the host and in male and female A. galli. The survival of the chickens and gain in body weight were improved, and the restoration of microelement content was observed by treatment with the salt. A positive effect of the basic Zn-Co-Mn salt was also observed in the nematode microelement levels. Significant differences were found between the levels of zinc, cobalt and manganese in male and female A. galli.

Administration of Zn-Co-Mn basic salt to chickens with ascaridiosis. I. A mathematical model for Ascaridia galli populations and host growth with and without treatment.

A newly synthesized basic mixed salt (Zn(x)Co(y)Mn(1-x-y)) x (OH)6SO4 x 2H2O) was administered to chickens with ascaridiosis. Improvement in survival, gain in body weight (of 19.03%) and restoration of microelement content were observed in the treated chickens. An increase in the gain in body weight of 7.62% in uninfected treated chickens was also observed. The establishment of Ascaridia galli populations in chickens, and chicken growth in control and infected hosts, untreated and treated, were modelled mathematically. Some kinetic parameters (the rate of reduction of the nematode population nu and the relative rate mu of gain in body weight of the host) were determined. The values of nu =0.027 day(-1) and nu* =0.032 day(-1) were calculated for the reduction rates in infected, untreated chickens and in infected, treated chickens, respectively. The worm burden in infected, treated chickens was 20.4% lower than in infected, untreated chickens.

Effects of glycine-metal compounds on Ascaridia galli-infected chickens expressed by a kinetic model.

The biogenic elements zinc, manganese and cobalt are essential for metabolic processes in animals. Compounds of nGly.Me2+A. mH2O (Me2+=Zn2+, Mn2+, Co2+; A=Cl(-), SO4(2-), n=1, 2; m=2, 5), as supplements in the diet, were used separately on different experimental groups of male Hisex chickens to correct the mineral deficiency caused by Ascaridia galli infections. An amelioration of body weight gain, reduction of mortality and restoration of trace element levels were estimated in infected chickens. A mathematical model has been proposed for A. galli population kinetics in chickens, taking into account the stimulating effect of these elements on the nematodes. The model parameters are considered as phenomenological constants of the host-parasite system. An agreement with experimental data is observed using, for the parameters psi, alpha, micro and micros, values equal to those calculated in previously investigated A. galli-chicken systems. For parameter nu (immunological constant) the same value was obtained as in a previous experiment with high infection. This model is likely to be suitable for a range of host-nematode systems, including varying degrees of infection and treatment with different trace elements.

The effect of cobalt compounds on uninfected and Ascaridia galli-infected chickens: a kinetic model for Ascaridia galli populations and chicken growth.

The effect of dietary cobalt from three different sources on uninfected and Ascaridia galli-infected Hisex chickens, has been studied. The chicken diet was supplemented with 0.06 Co2+ kg-1 food either in the form of two glycine-cobalt compounds or mixed zinc-cobalt basic salt. An excess of dietary cobalt in small doses increases the gain of body weight and decreases host mortality. A greater bioefficiency of cobalt was established in infected chickens. A mathematical model has been used to provide a quantitative interpretation of the observed results. The model solutions of the kinetics of worm numbers and body weight are in a good agreement with experimental data. The model is valid for different degrees of A. galli infections and for treatment with different trace elements. The value of the kinetic parameter, regarded as a phenomenological constant of the host immune response, depends on the degree of infection.

Optimal treatment of Ascaridia galli-infected chickens with salts of trace elements and a kinetic model for chicken growth.

Data from seven experiments with Ascaridia galli-infected chickens have been considered. The results of treatment with neutral and basic copper, zinc and copper-zinc salts and inorganic and organic manganese compounds have been compared. An optimal therapy, containing a pure Cu basic salt (Cu2(OH)3Cl) and an organic Mn compound (2Gly.MnCl2.2H2O), is proposed to correct mineral deficiencies and pathological symptoms and to ensure lower mortality and higher gains in body weight. A mathematical model has been proposed for the growth of a healthy chicken. The relative rates for two growth stages have been determined by the model using data from mean chicken weights. The time course of the average biomass of a single A. galli has been theoretically derived from the same logistic equation describing chicken growth, which in turn might explain, phenomenologically, the mechanisms involved in the biomass growth of eukaryote organisms.