Effects Of Arginine On The Growth Perfmormance And Intestinal Function In Heat-stressed Finishing Pigs

Arginine(Arg)plays an important role in the regulation of growth performance,intestinal development,and immune function of pigs,however,under heat stress conditions,the mechanism of Arg has not been well understood.The study was conducted to explore the effects of dietary Arg supplementation on the growth performance in a heat-stressed-finishing pig model.With the high temperature 30 ? ± 5 ?and relative humidity 60% ± 5%,a total of 40 finishing pigs(Duroc ×Landrace ×Yorkshire;average body weight(BW)about 100.0kg)were randomly assigned to 4 treatments(10 pigs/ treatment),respectively: Control group(basal diet),treatment?(basal diet+1% arginine),treatment II(basal+1.5% arginine),treatment ?(basal diet+2% arginine).The whole experiment lasted 28 d.O n days 0,14,and 28,blood samples were collected aseptically in tubes from an ear vein.After the whole experiment,the growth performance,meat quality,carcass traits,and blood p Hysiological and biochemical parameters were determined.The results showed that under heat stress conditions,the average backfat thickness,ADG,F/G,nitrogen apparent digestibility,the brightness and red degree of fleshy sensory color,serum SOD concentration and The different intestinal segments for the ratio of villus height to crypt depth and villi surface areas of finishing pigs were remarkably decreased,however,the values of the loss of high water and serum MDA concentration were increased.When the dosage of Arg with 1.5% were added to the basal diet,the ratio of feed to gain(F/G=3.8)of finishing pigs was remarkably decreased(P<0.05);N itrogen apparent digestibility was 90.49%(P<0.05),and average backfat thickness was 3.05 cm,both of them was significantly increased(P<0.05);Fecal and urinary nitrogen contents differed(P<0.05),and the values were 5.25 g/d and 20.02 g/d,respectively;After 24 h of slaughter,the drip loss was remarkably reduced(P<0.05);The ratio of villus height to crypt depth and villi surface areas in the small intestine were significantly increased(P<0.05),and the values of the villus height to crypt depth in the duodenum jejunum,and ileum were 3.90 cm,3.52 cm,and 4.69 cm,respectively,villi surface areas were 439766 ?m2?414198 ?m2 and 396303 ?m2.After adding 1.5% Arg in the feed,the pig heat stress can be greatly reduced,improve the growth performance,repair the intestinal mucosa damage,improve bowel function.Therefore,under the heat stress conditions,Arg supplementation could significantly enhance the growth performance,improve carcass traits,and be conducive to recover intestinal functions,thereby alleviating heat stress.In addition,the dosage of Arg to 1.5% has a great benefit and remarkably increase the overall growth performance in finishing pigs.