Effects Of Fermented Feed And Weaning Age On Intestinal Health And Growth Performance In Piglets

The purpose of this experiment was to study the effects of fermentation diet and weaning age on growth performance,biochemical indexes and intestinal barrier function of piglets.One hundred twenty healthy Duroc×(Landrace×yorkshire)piglets were selected from 20 litters that per litter selected six piglets.Half of the piglets in the same litter were weaned at age of 21 days and half of the piglets continued to suckle until weaning at age of 28 days.The weaned piglets were divided into two groups: control group and fermentation group,which fed with control diet and fermentation diet respectively.There were four groups,5 replicates each group,6 piglets each replicate.The control diet was fed with corn soybean meal basic diet(without antibiotics,without high zinc and high copper).The basic diet was fermented as the fermented feed by Bacillus subtilis,Saccharomyces cerevisiae,Lactobacillus casei and Lactobacillus plantarum.The experiment lasted for 21 days.Two piglets close to the average body weight were slaughtered and sampled at the 28 th and 42 nd day of age respectively.The results were as follows:(1)At age of 21-28 days,The average daily gain of piglets in 21-day-old weaning control group and 21-day-old weaning fermentation group were significantly lower than that of suckling piglets(i.e.28-day-old weaning control group and 28-day-old weaning fermentation group were suckling piglets in 21-28 days old)in 1 week after weaning(P <0.01).The dry matter intake of piglets in 21-day-old weaning fermentation group was significantly lower than that in 21-day-old weaning control group(P < 0.05),but there were no significant differences in daily gain,the ratio of feed to weight and diarrhea rate between the two groups.During the whole period of the experiment(21-42 days old),the Fed fermented diet significantly increased the weight,average daily gain and average feed intake of weaned piglets at age of 42 days(P < 0.05),significantly reduced the average daily dry matter intake and ratio of feed to weight(P < 0.01),but there was no significant difference between 28-day-old weaned piglets and 21-day-old weaned piglets at age of 42 days.(2)The activity of serum diamine oxidase,the height of jejunal villi,the height of villi/ crypt,the expression of occludin and ZO-1 m RNA,the expression of ZO-1 protein in jejunum and ileum,and the expression of Occludin protein in ileum were significantly lower than those in suckling piglets(P < 0.05).The content of urea nitrogen in serum of piglets at age of 28 days in 21-day-old weaning fermentation group was lower than that in21-day-old weaning control group(P < 0.05),while the expression of ZO-1 protein and Occludin protein in jejunum and ileum were higher than that in 21-days-old weaning control group(P < 0.05),but there was no significant difference between the two groups in the morphology of small intestinal villi and the expression of tight junction protein m RNA.Different weaning days(28 / 21 days old)and diets(fermented diet / control diet)did not affect the serum biochemical indexes,the height of small intestinal villi and their ratio of crypt to depth of weaned piglets at age of 42 days,but the protein expression of ZO-1,Occludin and Claudin-1 in jejunum,and the protein expression of ZO-1 and Claudin-1 in ileum of 28-day-old weaned piglets at age of 42 days were significantly higher than that of21-day-old weaned piglets(P < 0.05).The expression of tight junction protein was increased by feeding fermented diet(P < 0.05).(3)The expression of cholecystokinin(CCK)m RNA and PYY m RNA in jejunum and ileum of 21-day-old weaning control group were significantly lower than that of suckling piglets(P < 0.05),and the content of n-butyric acid in colon was significantly higher than that of suckling piglets(P < 0.05).The expression of AMPKɑ2 m RNA in hypothalamus of21-day-old weaning fermentation group was higher than that of 21-day-old weaning control group(P < 0.05),but there was no significant difference in the expression of CCK and PYY m RNA between the two groups.Compared with 21-day-old weaned piglets,PYY m RNA expression in jejunum and ileum of 28-day-old weaned piglets increased significantly(P <0.05),while AMPKɑ2 m RNA expression in hypothalamus,CCK m RNA expression in jejunum and ileum,PYY m RNA expression in hypothalamus decreased significantly(P <0.05).The content of n-butyric acid in colon of piglets at age of 42 days fed with fermented diet was significantly lower than that of control diet(P < 0.05),but different weaning days(28 / 21 days)and diets(fermented diet / control diet)did not significantly affect the content of other volatile fatty acids in colon and cecum of piglets at age of 42 days.The results showed that 21-day-old weaning reduced the expression of intestinal tight junction protein and mucosal integrity,and decreased the growth performance of piglets after weaning for 1 week.The 42-day-old weight of piglets weaned at age of 28 days was similar to that weaned at age of 21 days,which means that delaying weaning for 7 days failed to improve the growth performance in the case of feeding non-antibiotic diet in weaned piglets with low diarrhea rate.Feeding fermented feed for 2-3 weeks can improve the growth performance and intestinal health,but feeding for 1 week did not obviously improve growth performance,although can increase the express of intestinal tight junction protein in weaned piglets.