The Study Of Developmental Characteristics Of Digestive System Of Dazu Black Goat

The trial adopts one-factor completely random design. The effect of age on digestive system of Dazu black goats was studied. Thus, the aim is to provide more reasonable parameters for feeding Dazu black goats.A total of42healthy Dazu black goats from Dazu were selected at the age of newborn,1week,2weeks,1months,2months,6months and1year, respectively, and each with6replictes. Developmental characteristics of digestive organs, protease activity in small intestine, rumen microflora were studied with different methods. The results showed that:1. According to the allomentary growth rate, it seems inconsistent of the digestive organs before the age. The liver, spleen and small intestine grow faster than the body weights before2months, then slightly lower after2months; While the stomach grow faster ervery stage over the year.2. The absolute weight of digestive organs increased gradually until the6months old approaching adult levels.And the weight gain descended magnitude ofdigestive organs and glands is:stomach, liver, spleen, small intestine. The length and volume of small intestine approach the adult level in6months old. The length of small intestine grow fastest from newborn to1week, while the volume from2to6months; The trend of stomach volume is almost the same, which significantly increases at6months(P<0.01), furthermore, the rumensignificantly increases at2months,1year old(P<0.01).3. The weight of liver, spleen, stomach and small intestine of Dazu black goats strongly correlate with weeks and the fitting curve were:Liver: y=-0.279x2+23.48x+27.45, R2=0.952, P=0.045 Spleen: y=-0.016x2+1.302x+4.722, R2=0.973, P=0.037Stomach: y=-0.435x2+35.97x-41.98, R2=0.960, P=0.039Small intestine:y=-0.357x2+26.96x+55.87, R2=0.987, P=0.021。The length and volume of small intestine of Dazu black goats strongly correlate with weeks before6months and the fitting curve were:Length: y=-0.788x2+57.35x+806.7, R2=0.996, P=0.003Volume: y=-1.976x2+177.3x+11.76, R2=0.969, P=0.008And the and volume of rumen, reticulum, omasum, abomasum of Dazu black goats strongly correlate with weeks before2months and the fitting curve were:Rumen:y=10.32x2+50.01x+41.10, R2=0.996, P=0.001Reticulum:y=4.156x+1.4, R2=0.992, P=0.001Omasum:y=0.129x2+0.052x+1.156, R2=0.993, P=0.001Abomasum: y=-0.277x2+21.99x-10.54, R2=0.964, P=0.0244. The relative volume of rumen, reticulum, omasum, abomasum of Dazu black goats in every segment are basically the same. The most significant change period is from2to6months (almost increase70%), and next is from1to2months(almost increase10%).5. Activities of amylase, trypsin, lipase in small intestine increase with the growth of Dazu black goats.There were significantlydifference between2weeks and1months、1and2months of amylase activities(P<0.05), which lipase were between newborn and1week、1week and2weeks、2and6months, lipase were between newborn and lweek、1and2months. There is no significant changeafter2months of amylase and lipase,6months of trypsin;6. Quantities ofmajor rumen microorganisms increase gradually with age. Ruminococcus albus, Ruminococcus flavefaciens, Butyrivibrio fibrisolvensand Fungi in rumen increase obviously with the growth of Dazu black goats, which methanogens was after2months. Another, quantities of Ruminococcus albus, Ruminococcus flavefaciens and Fungichanged significantly between1and2months,2and6months(P<0.01); Quantities ofRuminococcus flavefaciens, Butyrivibrio fibrisolvens and Fungi changed significantly between6months and1year(P<0.01).