Effect of dietary available phosphorus and phytase on production performance of old laying hens and tibia bone quality

سال انتشار: 1394
نوع سند: مقاله ژورنالی
زبان: انگلیسی
مشاهده: 331

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شناسه ملی سند علمی:

JR_IJVM-9-2_004

تاریخ نمایه سازی: 15 شهریور 1395

چکیده مقاله:

BACKGROUND: Old laying hens are more prone to dietary calcium(Ca) and phosphorus (P) deficiencies as they absorb Caand P less efficiently than younger hens. OBJECTIVES: In a 2×2factorial design, the influence of diets with two levels of availablephosphorus (AP) and phytase enzyme on the laying performance,egg quality and tibia bone characteristics of layinghens at their late 2nd production phase was studied. METHODS:The experiment used four treatments of 20 Hy-Line W36 hensof 140 weeks old. Treatments 1 and 2 received a 3.5 g kg-1 APdiet while Treatments 3 and 4 received a 2.5 g kg-1 AP diet for12 weeks. Treatments 2 and 4 received 250 FTU kg-1 phytasein their diet. Laying performance, egg weight, shell weight andshell thickness were measured. On the last day of the experiment,all birds were weighed and blood samples were collectedfor serum Ca and P measurements. Ten birds from each treatmentwere sacrificed and both tibiae were excised, defatted,weighed and ashed for Ca and P contents, cortical thicknessand bone breaking strength measurements. RESULTS: Hens fedwith 2.5 g kg-1 AP diet without enzyme had the lowest bodyweight gain, serum P, tibia cortical thickness and tibia breakingstrength among the treatments (p<0.05). Phytase enhancedbody weight gain, egg shell thickness, serum P, tibia weight/body weight and tibia ash/body weight ratios, tibia corticalthickness and breaking strength, particularly in birds receiving2.5 g kg-1 AP diet (p<0.05). CONCLUSIONS: Phytase mayimprove bone quality and strength of hens in the late 2nd layingperiod.

نویسندگان

B Mansoori

Department of Animal and Poultry Health and Nutrition, Faculty of Veterinary Medicine, University ofTehran, Tehran, Iran

M Modirsanei

Department of Animal and Poultry Health and Nutrition, Faculty of Veterinary Medicine, University ofTehran, Tehran, Iran