Effect of Microbial Phytase in Soybean Meal Based Broiler Diets Containing Low Phosphorous

Effects of dietary calcium and phosphorus restrictions on growth performance, intestinal morphology, nutrient retention, and tibia characteristics in broiler chickens

1. This study evaluated the effects of dietary calcium (Ca)‎ and available phosphorus (aP) restrictions on growth performance, intestinal morphology, nutrient apparent total tract retention (ATTR), and tibia characteristics.2. A total of 1296, one-day-old male Ross-308 broilers were reared for 42 d. During the ‎starter phase (1-10 d), all birds were fed a nutrient-adequate diet (C). Diets fed during the grower phase (11-24 d) included: 1. C; 2. 15% of the Ca and aP in C; 3. 30% of the Ca and aP in C. At the beginning of the finisher phase (25 d), chickens fed the C diet were divided into two subgroups including C, and C+ phytase (500 FTU/kg). Restricted treatments were divided into eight subgroups as 1. C; 2. 10% of the Ca and aP in C; 3. 20% of the Ca and aP in C; 4. 30% of the Ca and aP in C; 5. C+ phytase; 6. 10% of the Ca and aP in C+ phytase; 7. 20% of the Ca and aP in C+ phytase and 8. 30% of the Ca and aP in C+ phytase.3. On d 24 and 42, ATTR of Ca and phytate phosphorus (pP) were linearly increased by decreasing Ca and aP levels (P<0.05). Birds receiving phytase showed higher nutrient ATTR ‎compared to those fed non-phytase supplemented diets (P<0.05). Tibia Ca and P were linearly decreased at 24 d (P<0.05) and tibial ash was linearly decreased (P<0.05) at 42 d by decreasing levels of Ca and aP in finisher diets (without phytase)‎. By decreasing the levels of Ca and aP in the finisher diets (with phytase) with a 30% reduction of Ca and aP in the grower phase, tibia ash linearly decreased (P <0.05). Using 500 FTU/kg phytase improved tibia traits compared to non-phytase supplemented treatments (P<0.05).4. In general, decreasing dietary Ca and aP (up to 30%) during grower and finisher phases increased ATTR of minerals and decreased Ca, P and breaking strength (BS) of tibia without any negative effect on growth performance or intestinal morphology. Reduced dietary Ca and aP decreased tibial ash content, although 500 FTU/kg phytase improved ATTR of minerals and tibia attributes.

Effects of Adding Phytase from Aspergillus niger to a Low Phosphorus Diet on Growth Performance, Tibia Characteristics, Phosphorus Excretion, and Meat Quality of Broilers 35 days after hatching

This study was designed to determine the effect of phytase extracted from Aspergillus niger (Natuphos^® E) on growth performance, bone mineralization, phosphorous excretion, and meat quality parameters in broilers fed available phosphorous (aP)-deficient diet. In total, 810 one-day-old Indian River broilers were randomly allotted into one of three dietary treatments, with six replicates per treatment. The three dietary treatments were 1) control group (CON: basal diet with sufficient aP), 2) low phytase (LPY: available phosphorus-deficient diet supplemented with 0.01% phytase), and 3) high phytase (HPY: available phosphorus-deficient diet supplemented with 0.02% phytase). Average daily gain and, feed intake, and feed conversion ratio were measured for 35 days. Excreta were collected from each pen on day 35. One broiler from each cage was euthanized to collect visceral organs and tibia samples. Broiler chickens fed LPY and HPY showed improved (P<0.05) growth performance compared to broilers fed CON on day 35. The tibia length of HPY-fed broilers was more than those of broilers fed other diets on day 35 (P<0.05). However, tibia calcium and phosphorous contents in LPY-fed broilers was higher (P<0.05) than in CON and HPY-fed broilers. Tibia length and calcium and phosphorous content showed a positive correlation (P<0.05) with the weight gain of broilers on day 35. Phosphorous level in the excreta of LPY- and HPY-fed broilers was lesser than those of CON broilers on day 35 (P<0.05). Furthermore, HPY-fed broilers showed lower (P<0.05) phosphorous content in the excreta than LPY-fed broilers. LPY- and HPY-fed broilers showed higher (P<0.05) liver weight than the CON broilers. In conclusion, broilers fed aP-deficient diet supplemented with phytase from Aspergillus excreted less phosphorus, which enhanced growth performance and tibia development from time of hatching to day 35 post-hatching.