The objective of this experiment was to investigate the effects of different calcium (Ca), non-phytic phosphorus (NPP) levels and electrolyte balance (DEB) value in a low protein diet on growth performance, serum biochemical indices and metabolic rate of nutrients in broilers. A 3×3 two-factor completely randomized design was adopted. Three dietary calcium and non-phytate phosphorus levels were 0.70% Ca and 0.35% NPP, 0.80% Ca and 0.40% NPP, 0.90% Ca and 0.45%NPP, respectively. And three levels of dietary electrolyte balance (Na++K+-Cl-) were 200, 250 and 300 mmol·kg-1, respectively. In addition, dietary crude protein level was 19.5%. A total of 324 1-day-old Arbor Acres (AA) male broilers were randomly allotted to 1 of 9 treatments with 6 replicate cages per treatment and 6 birds per cage. The experimental period was 21 days. The results showed that: 1) Dietary Ca, NPP and DEB value and their interaction had no significant effect (P>0.05) on growth performance of broilers from 1 to 21 d of age; 2) The interaction of dietary Ca, NPP and DEB value had significant effect (P<0.05) on the alanine aminotransferase (ALT) activity in serum. As dietary Ca and NPP levels were 0.70% and 0.35%, the serum ALT activity from broilers in the 300 mmol·kg-1 DEB value group was significantly higher (P<0.05) than that of the 200 and 250 mmol·kg-1 DEB value groups. As the levels of Ca and NPP were 0.80% and 0.40%, the serum ALT activity from broilers in the 250 or 300 mmol·kg-1 DEB value groups was significantly lower (P<0.05) than that in the 200 mmol·kg-1 DEB value group. As the levels of Ca and NPP were 0.90% and 0.45%, DEB levels had no significant effect (P>0.05) on serum ALT activity; 3) As dietary Ca and NPP levels increased, the apparent metabolic rate of Ca decreased significantly (P<0.05). The apparent metabolic rates of dry matter, crude protein and Ca in broilers from 300 mmol·kg-1 DEB value group were significantly higher (P<0.05) than those in 250 and 200 mmol·kg-1 DEB value groups. As the levels of dietary Ca and NPP were 0.70% and 0.35%, 300 mmol·kg-1 DEB value could significantly increase (P<0.05) the apparent metabolic rate of P compared with the 200 and 250 mmol·kg-1 DEB value. And as the levels of Ca and NPP were 0.90% and 0.45%, the apparent metabolic rate of P in 300 mmol·kg-1 DEB value group was significantly higher (P<0.05) than that in the 200 mmol·kg-1 group. These results indicated that the Ca and NPP levels of 0.80% and 0.40% and DEB value of 300 mmol·kg-1 in a low protein diet (Crude protein: 19.5%) were optimal for the growth and nutrient utilization in broilers from 1 to 21 d of age.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |