Effect Of Rumen Protozoa On Feed Degradability And Diet Digestion

An experiment was conducted to study the in situ degradation and the digestion of the whole digestive tract between the defaunation or refaunation on two different diet protein level .Two adult yellow cattle fitted with rumen cannulas were defaunted by intro-ruminal infusion of sodium dodecybenzene sulfonic acid 100ml/d.The experiment is divided into four periods: (1)Defaunation with diet crude protein level 12.7% and net energy level 4,63MJ/Kg (2)Defaunation with diet crude protein level 8.9% and net energy level 4.72MJ/Kg (3)Refaunation with diet crude protein level 12.7% and net level 4.63MJ/Kg (4)Refaunation with diet crude protein level 8.9% and net energy level 4.72MJ/Kg.The results show that:(1) Crude protein potential degradability of rice straw remained unchanged (P=0.158); Dry matter(DM) potential degradability of the rice straw increased after defaunation(P=0.195) ,Biit the difference is not significant.(2) The potential degradability of neutral detergent fiber (NDF),acid detergent fiber(ADF) in straw remained unchanged after defaunation(P>0.05).(3) Defaunation increased significantly the potential degradability of DM,CP in concentrate l(P<0.05);Defaunation increased the CP potential degradability of concentrate 2. (P=0.079).,but the difference is not significant.(4) The potential degradability of crude protein in fish meal decreased after defaunation(P=0.059).No difference was observed in DM of fish meal.(P>0.05).(5) The potential degradability of crude protein in cotton seed meal (CSM) increased after defaunation(P<0.05);but no significant difference was measured in the CP potential degradabilty of soybean meal (SBM)and rape seed meal. (RSM)(P>0.05).(6) After defaunation the potential degradability of DM in cotton seed meal, rape seed meal enhanced significantly both.(P<0.05).(7) The potential degradability of DM in rice straw, concentrate 1, concentrate2; RSM, CSM increased significantly with diet 1(P<0.05), and also in CP of concentrate1 (P<0.05); The diet protein level affect the potential degradability of CP in rice straw (P=0.084), concentrate2 (P=0.079).(8) The digestibility in the whole digestive tract of dietary dry matter, neutral detergent fiber and acid detergent fiber increased after refaunation but no significant difference was observed. (P>0.05)(9) No difference in pH was measured between defaunation and refaunation, and also it was between two diets(P>0.05).(10)The concentration of NH3-N in the rumen was significantly increased (P<0.01) after refaunation, and it enhenced significantly (P<0.01)with the diet protein level increasing.