Different Sources Of Tannic Acid Replacing High Zinc For Weaning Piglets Growth Performance,Biochemical Indicators And Environmental Impact

The experiment aims to study to feed the control group of weaned piglets by adding four different sources of gallnut tannin such as gallnut whole powder,gallic hydrolyzed tannic acid,gallnut whole powder coating,gallic hydrolyzed tannic acid coating.And their growth performance,feed appearance digestibility,serum indicators,immune indicators,ammonia concentration,zinc emissions from feces,and feed costs have been compared,and the feasibility of using gallnut tannins from different sources to replace high-zinc rearing piglets has been studied.225 healthy piglets with uniform growth of 30 days old were selected.The ratio of male to female was the same,and they were randomly divided into different groups.Three parallel experimental groups were set up and kept in separate columns.One control group fed with zinc oxide,and other four experimental groups fed with different sources of gallic acid tannic acid.The experiment was carried out for 25days.The experimental results are as follows:（1）Growth performance:There was no significant difference in growth performance between the control group and the experimental group（P>0.05）.But it was found that a notable difference in diarrhea rate between the control group and the experimental group（P<0.05）,further,the diarrhea rate of the experimental group gradually decreased with time.After 15th day,it was same in the diarrhea rate（P<0.05）between the experimental group and the control group.The diarrhea rates（P>0.05）of control group and other four experimental groups were 0,1.56%,2.93%,1.20%,and 2.56%,respectively,during the days of 16-25.The diarrhea rates of the whole experimental period（i.e.25 days）were 1.45%,2.65%,3.08%,4.01%,and 3.5%,for control group and the four experimental groups,respectively,and there was a significant difference observed（P<0.05）.The experimental results show that feeding of piglets with tannic acid from different sources could promote the reduction of diarrhea rate after 2 weeks.（2）Apparent digestibility:It was observed that Galla Chinensis obtained from different sources can help to increase the digestibility of crude protein and crude fat in weaned piglets.At the same time,there was no significant difference found in the protein digestibility between the control group and the experimental group fed with the gallnut whole powder and gallnut hydrolyzed tannic acid acquired from different sources（P>0.05）.There was a significant difference（P<0.05）between the experimental group and the control group,the gallnut whole powder,and the gallnut hydrolyzed tannic acid experimental group（P<0.05）.In particular,the digestibility of the gallstone-hydrolyzed tannin coating experimental group was 5.36%,5.85%,and 6.94%higher than that of the control group,the gallnut whole powder,and the gallnut hydrolyzed tannic acid experimental group,respectively.There was a remarkable difference in crude fat digestibility between the control group and the four experimental groups（P<0.05）.（3）Serum index:The serum urea nitrogen content in the four experimental groups was 0.16mmol/L,0.78 mmol/L,0.5 mmol/L and0.25 mmol/L,respectively,but the difference was not noticeable（P>0.05）.The total protein content of the experimental group of Galla Chinensis was 3.38g/L,5.04g/L,7.85g/L,and 4.64g/L,respectively,which were not significantly different（P>0.05）.（4）Serum antibody index:It was almost same in the content of Ig A,Ig G and Ig M between the control group and the four experimental groups（P>0.05）.It shows that tannic acid from different sources can promote the immunity of piglets and can replace zinc oxide.（5）Ammonia emission:The ammonia concentration of feces in the four experimental groups shows a trend of decreasing with the passage of time,and the effect of the gallnut whole powder experimental group was the best.The ammonia release rate of the gallnut whole powder experimental group was significantly lower than that of the control group and the other3 experimental groups（P<0.05）.There was no significant difference in fecal ammonia concentration between the experimental group and the control group on the first day of the experiment（P>0.05）.On the 20th day,the ammonia concentration of the gallnut whole powder experiment group and the gallnut hydrolyzed tannic acid coating group decreased by85.6%and 26.6%,compared with the control group（P<0.05）.In concludes that the gallnut whole powder can effectively reduce the ammonia emission in the feces.（6）Zinc content in fecal excreta:There was a notable difference in zinc content in feces between the four experimental groups and the control group（P<0.05）,and the zinc content in the stool of the control group was 55.95%higher than that in the four experimental groups,52.98%,49.71%,59.21%.It shows that different sources of gallnut tannin can replace zinc oxide to reduce zinc emissions in pig manure.（7）There was no significant difference in feed cost between pigs in the experimental group and the control group（P>0.05）,indicating that the use of different gallnut tannins instead of zinc oxide did not increase the burden of aquaculture feed costs,so gallnut tannins from different sources can replace zinc oxide.Finally,using the principal component comprehensive evaluation model to establish the regression equation for the growth performance of weaned piglets:y=31.65 x₁+58.48 x₂+31.73 x₃+（-57.70）x₄.A comprehensive score ranking was performed for each experimental group.The scores of the control group and the gallnut tannins from 4 different sources were:123.99,114.10,111.58,107.83,and 107.87,respectively.The control group had the best effect,the gallnut whole powder,the gallnut hydrolyzed tannin acid,the gallnut coating,and the gallnut hydrolyzed tannic acid coating effect was lower than the former two.The above experiments show that in the existing breeding environment,the use of tannins instead of zinc oxide from different sources has certain limitations,but has no significant effect on the growth performance of piglets.From the perspective of environmental protection,tannins from different sources can effectively reduce the emission of ammonia and zinc,play an important role in environmental protection,can replace the use of zinc oxide,and the best effect of gallnut whole powder and gallnut hydrolyzed tannic acid.