Effects Of Enzyme Preparation And Energy Level On Growth Performance, Gut Development And Digestive Enzyme Activity In Broilers

This study was conducted to investigate the effects of exogenous enzyme andmetabolizable energy level on growth performance, gut development and digestiveenzyme activities of broilers.Four hundred one-day old Cobb broilers (49.46±0.96g) were assigned to a2×2factorial arrangements with dietary energy level (ME12.13MJ/kg or ME11.92MJ/kg) and dietary supplementation of exogenous enzyme (0and1%) as themain factors. Each treatment group had5replicates(10broilers per replicate forfour replicates and36broilers per last replicate). The experiment lasted for21days. On7d,14d, and21d birds body weight and feed intake were recorded formeasuring growth performance. On days1,3,7,10,14, and21, five birds fromeach replicate were killed for obtaining the sample of muscular stomach,glandular stomach, pancreas, duodenum, jejunum and ileum. The enzymeactivities of pepsin, trypsin, and pancreatic lipase, amylase and disaccharidaseswere determined. The gastrin in the glandular stomach and duodenal was alsomeasured. The results show as followed:1. The effect of exogenous enzyme and energy level on growth performance inbroilers.Compared with the ME11.92MJ/kg (low-energy, LE) group, the ME12.13MJ/kg group (high-energy, HE) significantly decreased the ratio of feed/gain (F/G)by4.88%(1~7d),6.21%(1~14d), and6.49%(1~21d)(P<0.05). On d14, dietarySupplementation of0.1%enzyme preparation increased the average daily gain(ADG) by6.53%(P<0.05) in comparison with diet in the absence of enzymepreparation. There was an interaction between the energy level and enzyme onADG on14day (P<0.05).2. The effect of exogenous enzyme and energy level on digestive tractdevelopment in broilers.Dietary supplementation of0.1%enzyme preparation decreased the relative weight of glandular stomach, duodenum and jejunum on3d, pancreas on7d, andileum on10d (P<0.05) compared with the diet without supplementation of enzymepreparation; However, it increased the relative weight of muscular stomach andglandular stomach on21d (P<0.05). Compared with the HE group, the LE groupreduced the relative weight of the jejunum, ileum and the proportion of ileum inthe small intestine, the relative weight of muscular stomach (d14), length andweight/length percentage of duodenal (d21)(P<0.05); it also resulted in anincrease of the length of ileum (P<0.05). The relative weight of muscular stomach,glandular stomach, duodenum, jejunum, and ileum reached the top on3d.3. The effect of exogenous enzyme and energy level on activities of digestiveenzyme in broilers.Dietary Supplementation of0.1%enzyme preparation increased the activities ofpancreatic lipase (7d,10d, and14d), amylase (3d,7d,10d, and21d), trypsin (3d,and21d), and pepsin (7d,10d, and21d)(P<0.05), whereas decreased theactivities of pancreatic lipase (21d), amylase (14d), trypsin (7d,10d, and14d),and pepsin (3d and14d)(P<0.05). Birds receiving the diet of LE had a loweractivities of pancreatic lipase (7d, and14d), amylase (14d, and21d)(P<0.05), anincreased activities of trypsin (3d,7d,14d, and21d) and pepsin (14d, and21d)(P<0.05) compared with the birds of HE group. There was a interaction betweenenzyme preparation and energy level on the activities of pancreatic lipase (10d,14d, and21d), amylase(3d, and21d), trypsin (3d, and10d), and pepsin (3d,7d,14d, and21d)(P<0.05).4. The effect of exogenous enzyme and energy level on the activity of intestinaldisaccharidases in broilers.Dietary Supplementation of0.1%enzyme preparation reduced (P<0.05)sucrase activity of jejunum (3d,10d, and21d), duodenum, and ileum(3d,7d, and21d), decreased maltose activity of ileum(21d) and duodenum(21d)(P<0.05),whereas increased isomaltase activity of duodenum(3d and21d) and ileum(10d,14d and21d)(P<0.05). Birds receiving the diet of LE had higher maltase activities of duodenum(3d and21d), jejunum(3d) and ileum(14d)(P<0.05), higherisomaltose activity of duodenum(3d,10d,14d and21d), jejunum(3d), ileum(14dand21d)(P<0.05), higher saccharase activity of duodenum(3d,14d and21d),jejunum(10d and21d), ileum(14d)(P<0.05). There was a interaction betweenenzymes and energy level on the disaccharidase activities of duodenum(3d),jejunum(14d), ileum(3d,7d,10d,14d and21d)(P<0.05).5. The effect of exogenous enzyme and energy level on gastrin in broilers.Dietary Supplementation of0.1%enzyme preparation reduced the gastrin (3d)(P<0.05), whereas increased the gastrin (10d,14d, and21d)(P<0.05). Birds of LEgroup had a lower level of the gastrin (3d,10d,14d, and21d)(P<0.05). There wasa interaction between enzyme preparation and energy level on gastrin (10d and14d)(P<0.05).In conclusion,(1) Diet supplemented with enzyme preparations and low metabolizable energylevel could reduce the digestive organs index of10-day old broilers.(2) Diet supplemented with enzyme preparations could influence the activitiesof digestive tract endogenous enzymes in broilers, and diet with Lowmetabolizable energy levels increased the activities of protease and disaccharidesof broilers.(3) There was an interaction of Enzyme preparation and metabolizable energylevels on ADG and FCR of broilers (14d). Diet (metabolizable energy level=12.13MJ/kg) supplement of0.1%can improved the growth performance of broilerchickens.