Acta Vet. Brno 2008, 77: 199-207
Administration of Clinoptilolite to Broiler Chickens During Growth and Its Effect on the Growth Rate and Bone Metabolism Indicators
The growth rate and bone metabolism indicators were monitored in broiler chickens receiving the feed supplemented with clinoptilolite. One-day-old broiler chickens ROSS 308 were divided into control (C) and experimental (E) groups with 100 males and 100 females per group. The chickens received the complete feed mixture BR1 from 1 to 10 days of age, followed by the feed mixture BR2 until the age of 30 days, and the feed mixture BR3 until the end of the experiment (40 days). The feed mixtures of the experimental group were supplemented with clinoptilolite (commercial additive ZeoFeed) at a level of 0.5% (BR1), 1.5% (BR2) and 2.5% (BR3), replacing the corresponding portion of wheat. Feed mixtures and drinking water were provided ad libitum. The live weight of broiler chickens in both the control and experimental group increased steadily during the experiment. At the end of the experiment, live weights of experimental females (2,416 g) and males (2,829 g) were higher than those of control females (2,345 g) and males (2,694 g) by 3% and 5%, respectively. Significant differences in the live weight between groups were found from the age of 30 days (P ⪬ 0.05 and P ⪬ 0.01). At the age of 40 days, the chickens were slaughtered and the femur and tibiotarsus of the right leg were analysed for the content of dry matter, ash, calcium, phosphorus and magnesium. The ash content in dry matter ranged from 53.0 to 54.1% in group C and from 51.7 to 53.2% in group E. The Ca and P contents in dry matter in group E were lower than those in group C, except for Ca and P in the male tibiotarsus. In both groups, regardless of sex, the ash content was higher in the tibiotarsus than in the femur. Since fat levels in bones of the experimental group were increased (females by 19.5% in the femur and 21.3% in the tibiotarsus; males by 22.0% in the femur and 26.3% in the tibiotarsus), which could affect the values obtained, ash, calcium, phosphorus and magnesium were determined in the fat-free dry matter. The trends found in the originally determined dry matter were maintained, i.e. lower levels of ash, Ca, and P in the experimental group, except for male Ca in both kinds of bones. The corresponding levels in the fat-free dry matter were relatively higher as compared to the original dry matter. The results of the study showed that up to 2.5% of clinoptilolite in the diet had no adverse effect on performance and bone metabolism indicators of growing broiler chickens. Thus, it can be used as a suitable feed additive to broiler diets due to its positive effect on nutrient utilization, mechanism of digestion and pollutant elimination in connection with food safety issues.
Keywords
ZeoFeed, weight of chickens, bone tissue, ash, calcium, phosphorus, magnesium.
