Effects Of Calcium Formate And Calcium Citrate Instead Of Calcium Carbonate In Antibiotic-free Diet On Growth Performance,Calcium Metabolism And Immune Function Of Weaned Piglets

In the formula feed production of pigs,calcium carbonate is usually used as a calcium source,which has high calcium content,but its digestion and absorption need gastric acid.Because the gastrointestinal tract of piglets is not fully developed,it is easy to cause diarrhea,reduce their growth and breeding benefits.As a feed additive,organic acids have been studied by many scholars.Calcium formate has been widely studied in animal nutrition,but the results of different scholars are quite different.Calcium citrate is widely used in human calcium supplementation,but there are few reports of animal nutrition.Therefore,it is necessary to further research effects of calcium formate and calcium citrate instead of calcium carbonate.This experiment was conducted to use calcium formate and calcium citrate instead of calcium carbonate as calcium sources in antibiotic-free diet,to research effects on growth performance,diarrhea,digestion and metabolism of Ca and other nutrients,antioxidant capacity,immunity and breeding benefits of weaned piglets,so as to provide a reference for calcium formate and calcium citrate as calcium sources instead of calcium carbonate.A total of 180 DYL weaned piglets（8.38±0.32kg,26 days old）were randomly divided into 3 dietary treatment groups,with 6 replicates per treatment and 10 pigs per replicate.The control group was fed a diet with calcium carbonate as the calcium source,and the experimental groups were fed a diet with calcium formate and calcium citrate instead of calcium carbonate at a same Ca level.The pre-feeding period lasted 7 days and the feeding experiment lasted 39 days.Pigs were weighed at the beginning,15^th day,and at the end of the experiment.Blood samples,fecal samples and feed samples were collected at the end of the experiment,they were used to determine indicators such as dietary acid binding value,serum,nutrient digestibility and so on.The results showed as follows:（1）Calcium citrate in the diet of piglets had a tendency to reduce the ratio of feed to gain（F/G）and improved the growth performance of piglets.During 16^th-39^th days,the feed intake（ADFI）of calcium citrate group was significantly lower than control group（p<0.05）,but there was no significant difference in daily gain（ADG）（p>0.05）.The F/G tended to lower than control group（p=0.089）.（2）Diarrhea of piglets in calcium formate group and calcium citrate group was significantly decreased,and diarrhea rate and diarrhea index of calcium formate group and calcium citrate group were significantly lower than control group（p<0.05）.（3）Digestibility of Ca and other nutrients in calcium citrate group was improved.The digestibility of Ca,Ash,TP and CP in calcium citrate group were significantly higher than control group（p<0.05）.Calcium absorption and utilization of piglets in calcium formate group and calcium citrate group was significantly improved.The blood calcium content of piglets in two groups was significantly higher than control group（p<0.05）,parathyroid content was significantly decreased（p<0.05）.The ALB tended to be higher in the calcium citrate group than control group（p=0.08）.Dietary acid binding values were significantly decreased in calcium formate and calcium citrate groups（p<0.05）.（4）There were no significant differences in WBC,LYM,NC,EC,BC,MONO,RBC and PLT among the three groups（p>0.05）.These results indicate that calcium formate and calcium citrate had no negative effects on the body health of piglets.Serum Ig G and Ig M contents of calcium formate group and calcium citrate group were significantly higher than control group（p<0.05）.These results indicate that calcium formate and calcium citrate improved immunity of piglets（5）The antioxidant ability of piglets was improved,and the GSH-Px activity of calcium formate group and calcium citrate group was significantly higher than control group（p<0.05）.The T-SOD activity tended to be higher in the calcium citrate group than in control group（p=0.068）.（6）calcium formate and calcium citrate as dietary calcium sources reduced the gain feed cost by 2.46%and5.88%,and improved the breeding profit per kg by 4.81%and 10.88%.In conclusion,calcium formate and calcium citrate instead of calcium carbonate reduced the acid binding value of the diet,significantly reduced the diarrhea,improved absorption and utilization of calcium,immunity and antioxidant capacity of piglets,and the effect of calcium citrate is better.In addition,the use of calcium citrate improved the growth performance of piglets.calcium citrate instead of calcium carbonate improved digestibility of Ca and other nutrients,and brought better breeding benefits of the piglets.Therefore,calcium citrate is a better choice of calcium source for piglets.