Zeólita (clinoptilolita) em dietas para poedeiras semipesadas

Abstract

The health of birds can be harmed by ammonia in high concentrations, affecting the respiratory system, compromising the performance of the birds, as well as the entire production system. The use of zeolite in the feeding of laying hens can reduce the emission of ammonia present in the excreta of birds into the environment through the adsorption process. The objective of this study was to evaluate the effects of supplementing zeolite (Clinoptilolite) levels in the feeding of laying hens in the laying phase at 54 weeks of age. The treatments were a control diet free of zeolite and five diets including increasing levels of zeolite (0.7, 1.4, 2.1, 2.8 and 3.5%). A randomized block design was used a total of 240 laying hens of the Isa Brown lineage were used, with eight replicates of five birds per plot, fed the experimental diets for four periods of 28 days. Evaluations of productive performance, egg quality, ammonia and excreta pH, organ weight (liver, pancreas, heart, intestine, proventriculus and gizzard) and measurement of in-testine and cecum length, hematology, serum biochemistry were carried out. The results were submitted to ANOVA and Dunnett's test and regression analysis at 5% probability. There was no significant effect of clinoptilolite levels on production. On the other hand, for the ammonia and pH variables, a linear plateau effect was observed through. Ammoniacal N and excreta pH differed from the control diet for all clinoptilolite levels, in which ammonia volatilization and excreta pH reduced by 46.9% and 4.6% when consuming the diets with 0.93% and 1.19% clinoptilolite, respectively. The reduction in excreta pH is justified by the protonation of ammonia (NH3) into ammonium ions (NH4+). There was a statis-tical difference for the absolute weight of the organs, it was verified through the test of means, higher liver weights in the inclusion levels with 2.1 and 2.8% of clinoptilolite, a relative increase of 24.6 and 15. 9%, respectively. In relation to the length of the intestine, it was greater for treatments 1.4; 2.1 and 2.8% clinoptilolite. Hematological and serum biochemical values did not differ between treatments. Thus, it was observed that the inclusion of clinoptilolite can be used to feed commercial laying birds up to 0.93% inclusion without affecting production performance and egg quality.