Preliminary Investigation Of Nematodes Parasitized In Goats In Guangxi Region And The Exploration Of Antiparasitic Effect Of Vegetable Tannins

Guangxi belongs to subtropical monsoon climate zone and possesses the advantageous natural conditions of development of goat production,as it provides with high yield and good quality of forage planting conditions and regional advantages.In recent years,with the increase of breeding density and change of the way of farming,parasitic diseases has become the main hazard to cause economic benefits of the goat,including gastrointestinal nematode disease is the most serious.Consequently,with the increasing seriousness of anthelmintic resistance and drug residues,looking for alternatives to chemiotherapy on the basis of goat nematodes epidemiological investigation to formulate scientific prophylactico-therapeutic measures is of great importance.The research contents include:the nematode species description that goats have infected in the past and the preliminary investigation nowadays in Guangxi region,seasonal variation of nematodes parasitized in goat abomasum and optimization of L3 of laboratory incubation system,condensed tannins extraction of local banana leaf and preliminary exploration of antiparasitic effect of several vegetable tannins.Firstly,all of nematode species description of goats in the specimen room of our university suggests that a total of 24 species of nematodes belong to 3 orders 6 families 8 subfamilies and 12 genera.In addition,423 goat feces in Dancun market of Nanning City are collected to investigate the infection status of nematodes,the results shows that the nematode infection rate is 87.10%and mixed infection is in severe cases,up to 7 species.The percentage of FEC that have achieved the theoretical requirements of deworming accounted for 65.96%,the highest is up to 315800.86 goats abomasums collected in winter and summmer are necropsied from 2014 to 2015 in Beihu market of Nanning City to investigate seasonal dynamics change of nematodes in goats in our region.It is concluded that the infection rates of nematodes in goat abomasum is as high as 72.09%.The main nematode is Haemonchus cohtortus in summer as Ostertagia ostertagi in winter and there are significant differences of infection rate and infection intensity among different seasons.Then optimization of L3 of laboratory incubation system indicates that mature female adults cultured in Earle's buffer at 37? CO2 gas environment for 8h ovulate automatically and eggs cultured in sterile fecal culture liquid/physiological saline mixture at 25 ? 100%humidity develop to L3 for 5~6d.In order to look for alternative approach for traditional chemiotherapy of parasitic disease,we explore the antiparasitic effect of vegetable tannins preliminarily.Firstly,organic solvent extraction method and sulphuric acid-vanillin assay are applied to extract and determinate condensed tannins of local banana leaf,the results reveal that 0.8%hydrochloric acid methanol as extraction agent,solid-liquid ratio at 1:14,heated at 90 ? to reflux fo 40 mins 3 times,extracting effect is better.Determination of condensed tannins of the banana leaf with proanthocyanidins as standards using sulfuric acid-vanillin method,linear regression equation:y=3.458x+0.0062,correlation coefficient R2=0.9972,the proanthocyanidin concentration in the range of 0.02 to 0.20mg/mL at 500nm keep a good linear relationship between the absorbance.The extraction rate of condensed tannins in local banana leaf is 2.80%.Secondly,the banana leaf tannins,grape seed tannins and Chinese gallnut tannins act on different development stages of H.contortus,including egg,larva,adult stage and so on,the results show that all of forementioned vegetable tannins play a significant role in antiparasitic effects.Condensed tannins of banana leaf show remarkable inhibitory effect in egg hatch assay,the inhibition ratio is up to 1000%.However,condensed tannins of grape seed maintain the highest inhibition ratio at 91.36%.Several vegetable tannins cause different degrees of damage in adult ovulation inhibition experiement,which result in female adults could not ovulate autonomously and play a role of antiparasitic effect.The experimental results in vitro provide the exploitation of banana leaf tannins extracts as feed additive or fresh leaf as a new non functional feed in part or entirely replace the traditional chemiotherapy with theoretical guidance and scientific basis,which is of great significance to the development of forage-saving and ecological farming goat industry in Guangxi region.