Özet:

This experiment was aimed to use natural zeolite as a feed additive to diet in old laying hens. 36 laying hens of ISA White strain were used, at age of 72 week. The hens were divided into three treatments and each treatment consisted of six replicates with tow hens each. A standard basic ration was used consisting of maize and soybean meal, and the zeolite was added according to the design of the experiment as follows, without zeolite (control T1), +0.5% zeolite (T2) and +1% zeolite (T3). The experiment lasted for 6 weeks. The collected data of performance and egg quality parameters were evaluated of 3 week basis period (1st period 72 -75 week, 2nd period 75 -78 week) and the entire period (72 -78 week). Results indicated that there was no significant effect of adding natural zeolite on the studied performance parameters feed intake (g/hen/d) and feed conversion ratio (g/g) or on the egg production (%), egg weight (g/hen) and egg mass (g/hen/d). However, it must be noted that the hens fed with zeolite at level of +0.5 and +1% showed a higher (p ˃ 0.05) egg productivity comparing to hens without zeolite. Regarding the egg quality parameters, no significant effect were observed between the treatments. However, there were only significantly improvement in egg shell ratio (%) and egg shell density (mg/cm2) when the data of 72 - 78 week were pooled and analyzed. In this study, the zeolite supplementation showed no effects on blood plasma composition. In conclusion, the adding of natural zeolite at inclusion rate of 1% had positive effect on egg production and improved the shell egg quality of old laying hens.

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