Study On Reducing Using Nitrogen And Phosphorus In Pigs Diet

In recent years, with the growing size of pigs, pollution problems have become more and more serious; especially nitrogen and phosphorus in manure can easily damage the surrounding environment. The study was conducted to investigate the effects of different germinateded wheat levels and ideal protein diet on production performance and nitrogen and phosphorus emissions of pigs. This study included four experiments:In trial 1, the effects of different germinateded wheat levels on the production performance of growing and fattening pigs were studied. Forty castrated boars (Suzhong Pigs) of weighted 34.70±3.05 kg were randomly divided into four experimental groups, every group had ten replicates, and there was one pig fed in single pigsty for each replicates. Control group was fed a corn-soybean meal diet without wheat supplementation and experimental diets supplemented with 20%,30% and 40% germinated wheat, decreased the use of corn and soybean meal, and hardly added CaHPO4. The trial was conducted for two periods:the growing (0-30d) and fattening period (31-50d). The results showed that, the ADG of three experimental groups had no significant difference with control group. In the growing period, the level of ADFI in three treatments was increased by 34.4%,24.4% and 24.3%(P<0.05), the level of F/G was increased by 7.7%,13.2% and 1.1%(P<0.05). In the fattening period, compared with control group, Treat Ⅱ group significantly increased the level of ADFI by 10.3%, and the ADFI of Treat Ⅲ and Ⅰ group was not significantly different with control group. The F/G of Treat Ⅰ group significantly added 11.1%, and the F/G of Treat Ⅲ and Ⅱ group had no significant difference with control group. In the total period, the ADFI of three experimental groups significantly increased 23.1%,19.0% and 17.6%, the F/G added 9.7%,13.5% and 14.1% significantly, the CP availability added 4.0%, 4.7% and 2.9% significantly, the energy availability added 4.4%,6.0% and 3.9% significantly, the Ca digestibility added 13.1%,15.8% and 15.7% significantly, the P digestibility added 95.9%,83.2.0% and 72.1% significantly. Considering the whole result, adding 20% germinated wheat can get the best production performance.In trial 2, the effects of different germinateded wheat levels on the skeletal development and the Ca and P in the blood of growing and fattening pigs were studied. Then whether each experimental group was short of phosphorus without adding CaHPO4 was discussed. The treatments were the same as that of trial 1. The results showed that, as to the ash of bone, Treat III group decreased 9.3% significantly compared with control group, Treat I and II group tended to reduce (P>0.05); as to the Ca of bone, Treat III group increased 5.4% significantly, Treat I and Ⅱ group had no significant difference with control group; as to the P of bone, three experimental groups had no significant difference with control group; as to Ca of blood, Treat III group increased 21.2% significantly, Treat I and Ⅱ group had no significant difference with control group; as to P of blood, Treat I and II group increased 13.9% and 16.8% significantly, Treat III group had no significant difference with control group. Those rusluts showed that, adding 20% and 30% germinated wheat on the phosphate-free diet did not affect the skeletal development and the Ca and P in the blood of growing and fattening pigs.In trial 3, the the effects of germinateded wheat on pigs digestibility of microelments and amino acids were studied. The treatments were the same as that of trial 1. The results shows that, the digestibility of Fe, Cu, Mn and Zn in three experimental groups significantly increased, as the best of three groups, Treat II group significantly increased 44.0%,82.3%,53.7% and 100.0%. Treat I group significantly increased 36.6%,47.9%, 35.7%and 55.4%. Treat III group significantly increased 38.7%,68.8%,37.4%and 81.8%. As to the gestibility of amino acids, except His, three groups significantly increased, and His tended to increase (P>0.05), Treat Ⅲ group’His and Arg are the highest, other amino acids in Treat II group are the highest. As to the improvement of amino acids’digestibility, Gly is the best, Lys is the better, Arg is the lowest. From the tesults, Treat II group can get the best digestibility of microelments and amino acids.In trial 4, the effects of low protein diet on the growing and fattening pigs were studied. Forty castrated boars (Suzhong Pigs) of weighted 33.57±2.54 kg were randomly divided into four experimental groups, every group had ten replicates, and there was one pig fed in single pigsty for each replicates. Control group was fed a corn-soybean meal diet (CP =16.4%) and Teat I group reduced the use of corn, increased the wheat, added the sesame meal and sprayed corn bran, and did not use Thr so that a balanced diet short of Thr (CP =14.4%) was made. On the basis of Treat I group, Treat II group added Thr, so Treat II diet was low-protein and amino-acid-balanced. Based on Treat II group, Treat III group added phytase, and Treat III diet was low-protein, low-phosphorus and balanced. The results showed that, as to the ADG, compared with control group, three experimental groups had significant reduction in the growing, fettenning and whole period, and in the whole period, three experimental groups significantly decreased 34.5%,85.7% and 44.4%; as to the ADFI, the Treat Ⅱ group in the growing period and whole period significantly decreased 40.7% and 30.55%, Treat Ⅰ and Ⅲ group tended to reduce (P>0.05); as to the F/G, three experimental groups had significant addition in the growing, fettenning and whole period, and in the whole period, three experimental groups significantly increased 22.8%,25% and 15.7%.In conclusion, by adding 20% and 30% germinated wheat instead of CaHPO4 can get good production performance. Adding 30% germinated wheat can get the best digestibility of microelments and amino acids And the low protein diet without soybean meal and with adding the sesame meal, sprayed corn bran and Thr, cannot get good growth performance.