Livestock-Based Farming Systems, Renewable Resources and the Environment
Influence of phytase supplementation to rice bran - based diets on the digestibility and phosphorus excretion in growing pigs
N T Long, T T B Ngoc and L T H Thao
National Institute of Animal Science, Vietnam
The study was conducted to determine the effect of phytase and carbohydrase supplementation to diets based on rice bran on the digestibility of dietary components and phosphorus excretion of growing pigs. The basal diet was composed of maize meal, fish meal, soybean meal and rice bran, in which rice bran was considered as feed rich in fibre and phosphorus. The basal diet was calculated to meet requirement of growing pigs according to NRC (1998). Four diets including a basal diet (diet I), a basal diet supplemented with phytase (diet II), a basal diet supplemented with carbohydrate enzyme (diet III), and a basal diet supplemented with phytase plus carbohydrate enzyme (diet IV). Four castrated male pigs (Landrace x Yorkshire ) with the initial body weight of 33 ± 1 kg were designed according to a 4x4 Latin square. The experimental period lasted 12 days, the first 7 days for adaptation to the diet and last 5 days for fecal and urine collection.
The results show that the diets had no impact on the feed intake (P>0.05). There were significant differences in the digestibility of DM, OM, CF, NDF and P among diets (P<0.05), exception of CP digestibility (P>0.05). The diets supplemented phytase had higher P retention and lower total P excretion than the diets without phytase supplementation (P>0.05). The enzyme supplementation to diets (diet II, III and IV) had lower N excretion than diet without enzyme supplementation (P<0.05). The N retention was different significantly among the diets (P<0.05), with the highest value for the diet supplemented both phytase and carborhydrase enzyme. In conclusion, enzyme supplementation to the diets improved the digestibility of dietary components and P and N retention..
Keywords: pigs, phytase, carbohydrase enzyme, phosphorus, digestibility