| This study on Comphor familia plant extracts (CFPE) consists of two parts. The extracting technics and inhibition of CFPE to urease activity in vitro were studied in the first part to evaluate the optimal extracting method, influence factors and optimal inhibition dosage. The production performance of weaned piglets fed diets containing different levels of CFPE was tested to determine the optimal dietary level reducing the NHs volatilization in the second part.In the first experiment, we measured the available content of the extracts obtained from Comphor familia plant leaves under different extracting temperature (90癈, 80癈 and 50癈), time (Ih, 3h, 5h, 8h, lOh and 24h) and method (distillation and permeation) by 95% ethanol as the extract solvent, then added them to the piglets feces at grads. The optimal extract technics and inhibition dosage was speculated by the results, the influence factors were also detected.It was discovered that the extract which was distilled at the temperature of 80 癈 for 24 hours, containing 7.29% available ingredient, was the most effective one and this technique is most optimal. The inhibitory ratio of this extract was 31.14% and the optimal dosage is 4ml CFPE per 5gfeces.In the second experiment, 576 Duroc X Landrace X L. Youkshire crossbred pigs, weaned at 30 ?1 days old, were selected out and allotted to six treatment groups: I : control; II: 2% CFPE 75 premix (CFPE 150mg/kg in diet); III: 2%CFPE 150 premix (CFPE 300mg/kg in diet); IV: 2% CFPE 225 premix (CFPE 450mg/kg in diet); V: 2% CFPE 300 premix (CFPE 600mg/kg in diet); VI: 1% CFPE 450 premix (CFPE 450mg/kg in diet) for a 38d feeding trial. Each treatment in 3 replicates, each replicate with 32 pigs in two adjacent pens that shared one wet-dry feeder. During the whole feeding period, pigs were fed mash with two phases feeding. The whole feeding experiment lasted 43d including 5d pretrail and 38d true trail. Piglets were fed with Phase I diet and Phase II diet at 30~54d and 55~68d period respectively. Individual pig weight and feedconsumed were measured at the end of trail, and three barrows and three gilts per treatment were bled to collect serum. In addition, the digestive experiments, with acid insoluble ash as indictor, were conducted at 3 days before the end of feeding trail.During the whole feeding period, feces samples were took at 7:30-8:00 am in every 7 days by airproof plastic bags to our lab, in order to measure the urease activity, urea concentration and total nitrogen content of it. The experiment results were introduced as six parts: performance, digestive trial, urease activity, urea concentrate, total nitrogen content and serum index.The results of performance showed that the final weight of group HI (2% CFPE 150 premix containing 150mg CFPE/kg in diet) and IV (2% CFPE 225 premix containing 450mg CFPE/kg in diet) was significant increased by 4.90%(P<0.05) and 4.89%(P<0.05), respectively. The average daily gain was increased by 7.94%(P<0.01) and 7.86%(P<0.01), respectively. The average daily feed intake between the six groups has no significant discrepancy. Feed: Gain (F/G) of group TV, VI, III and II significant decreased by 5.67%(P<0.01), 4.64%(P<0.01), 4.60%(P<0.01), 4.12%(P<0.05), respectively, compare to group I .Results of digestive trail during 30~54d piglets indicated that the digestibility of dry matter (DM) of group W, IH, VI, V, and groupII was increased by 5.94%(P<0.01), 5.71%(P<0.01), 4.94%(P<0.01), 4.23 %(P<0.01) and 3.75%(P<0.01) compare to group I, respectively. The results of Digestibility of crude protein (CP) showed that group IV, VI, V, and group IE, was increased by 5.53%(P<0.01), 4.58%(P<0.01), 4.22%(P<0.01) and 3.47%(P<0.01) compare to group I , respectively. The results also showed that group IV had the best digestibility of DM and CP during the six treatments and had a significant discrepancy between group I . Results of digestive trail during 55~68days piglets indicated that the digestibility of DM of group II, III, IV, VI and group V was increased by 5.5... |
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