An experiment was conducted to determine the effect of different combination calcium sources and particle size on performance and egg shell quality in layer hens. In the experiment, 198 brown laying hens at 44 week of age were randomly assigned into 11 treatments groups. The experimental diets consisted of different calcium sources (Fine limestone, large limestone, large oyster shell and large egg shell) and their different combination. The experimental unit consisted of a groups of three hens, thus each treatment was replicated six times. Different calcium sources and particle size addition to the laying hens diet had no significantly effect on body weight gain, egg production, egg mass, feed intake, feed conversion ratio, egg specific gravity, egg shell weight, egg shell thickness and egg shell breaking strength but egg weight had significantly affected by the treatments. The significantly highest egg weight was found in laying hens fed with 50 % fine limestone and 50 % large limestone. Dietary different Ca sources had a significant effect on Ca, P and Mg as mineral contents of eggshell and tibia. In the present study, when dietary large calcium sources (limestone, oyster shell and egg shell) had no effect on performance and eggshell quality parameters in laying hens. However, dietary containing at least 50 % large calcium sources had positive effect on mineral contents of tibia.
The objectives of this study were to estimate the protein degradability of extruded full fat soybean (ESB) by in situ (nylon bag) and in vitro enzymatic method and to develop an equation in order predict in situ degradability from in vitro values. In the study enzymatic technique; hydrolysis after 1 h (INV 1 ) and after 24 h (INV 24 ) by a purified protease extracted from Streptomyces griseus in a borate-phosphate buffer at pH 8 was used as in vitro method. Relationship between in situ effective protein degradability (INS E ) and in vitro degradability after 1 and 24 hours incubations (INV 1 and INV 24 ) were determined. In situ protein degradability was measured at 0, 2, 4, 8, 16, 24, and 48 and at 72 h incubations in the rumen of 3 Holstein cows. In the study INS E , INV 1 and INV 24 were determined as 58.05, 20.24 and 41.46% respectively. Despite there were differences between in situ and in vitro protein degradability values, correlation coefficients between in situ and in vitro protein degradability of ESB were high and regression equations for estimation of in situ from in vitro were found significant. As conclusion in vitro enzymatic protein degradability (INV 1 and INV 24 ) can be used for estimation of in situ effective protein degradability of extruded full fat soybean.
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