Effect of Phytase Transgenic Corn Supplemented in Feed Diets on the Utilization of Calcium and Phosphorus in Bama Boars

The study aimed to evaluate the nutritional composition and the efficacy of phytase transgenic corn. Ten-month old castrated Bama boars and replicated a 6×6 Latin square design were used to evaluate the effect of phytase on utilization of calcium of phosphorus. Six-dietary treatments included: Phosphorus adequate control diet (PC), PTC0 (low-phosphorus diet), PTC500 (lowphosphorus diet with 500 FTU phytase/kg in PTC), PTC1000 (low-phosphorus diet with 1000 FTU phytase/kg in PTC), PTC5000 (low-phosphorus diet with 5000 FTU phytase/kg in PTC), microbe500 (low-phosphorus diet with 500 FTU phytase/kg from Aspergillus Niger). Contents of the proximate components, minerals, vitamins and amino acid of PTC did not differ from CC. The PTC has lower concentrations of phytate phosphorus than CC, the apparent digestibility of calcium and phosphorus of the PTC0 group is lower (p<0.05). No obvious dose-dependent relationship about the apparent digestibility of calcium and phosphorus showed among PTC500, PTC1000 and PTC5000. Therefore, the nutritional compositions of PTC had substantial equivalence to that of control corn except for phytate phosphorus concentrations, the PTC addition can improve the apparent digestibility of phosphorus and calcium and reduce the excrement of inorganic phosphorus, PTC might be an economically efficient way to decrease environment pollutions.

Dietary calcium requirements of broilers fed a conventional corn-soybean meal diet from 1 to 21 d of age

Background The current calcium (Ca) recommendation for broilers is primarily based on studies conducted more than 30 years ago with birds of markedly different productive potentials from those which exist today. And the response indicators in these studies are mainly growth performance and bone ash percentage. Therefore, the present study was carried out to investigate the effect of dietary Ca level on growth performance, serum parameters, bone characteristics and Ca metabolism-related gene expressions, so as to estimate dietary Ca requirements of broilers fed a conventional corn-soybean meal diet from 1 to 21 d of age. Methods A total of 420 1-day-old Arbor Acres male broilers were randomly assigned to 1 of 7 treatments with 6 replicates (10 birds per cage) and fed the corn-soybean meal diets containing 0.60, 0.70, 0.80, 0.90, 1.00, 1.10 or 1.20% Ca for 21days. Each diet contained the constant non-phytate phosphorus content of about 0.39%. Results The average daily gain decreased linearly (P < 0.001) as dietary Ca level increased. The serum and tibia alkaline phosphatase (ALP) activities, tibia bone mineral density (BMD), middle toe BMD, tibia ash percentage, tibia breaking strength, and tibia ALP protein expression level were affected (P < 0.05) by dietary Ca level, and showed significant quadratic responses (P < 0.02) to dietary Ca levels. The estimates of dietary Ca requirements were 0.80 to 1.00% based on the best fitted broken-line or quadratic models (P < 0.03) of the above serum and bone parameters, respectively. Conclusions The results from the present study indicate that the Ca requirements would be about 0.60% to obtain the best growth rate, and 1.00% to meet all of the Ca metabolisms and bone development of broilers fed a conventional corn-soybean meal diet from 1 to 21 days of age.