| Three experiments were conducted to investigate the growth performance, nutrients utilization and digestive physiology responses of broilers to supplementation of lipase in diets of different nutrition levels and sources of fats. At22d and43d, relative length and relative weight of digestive tract and lipase activity of broilers were measured.Experiment1:Effects of Lipase in Different Energy Levels Diets on Growth Performance in BroilersA total of672day-old Cobb commercial male broilers were randomly allocated into8treatments according to arandomized complete block design. Treatments included:positive control diet (PC,1-21d AME12.13MJ/kg,22-42d AME12.76MJ/kg), Three negative control diets with energy decrease:NC1(-210kJ/kg), NC2(-420kJ/kg) and NC3(-630kJ/kg) with or without1000U/kg lipase addition. This experiment included two periods:starter (1-21days of age) and grower (22-42days of age) periods. The results showed as follows:1) Compared with the PC, The BW and BWG of NC1, NC2and NC3at every stages were tended to decrease (P>0.10), F/G of every stages were tended to increase with1-21d F/G of NC2and NC3were significant increased compared to PC and NC1(P<0.05),1-21d mortality in NC3was increased (P<0.05).2) Compared with NC1, NC2and NC3, BW and BWG of NC1, NC2and NC3with the addition of lipase at every stages were increased (P>0.10)(exclude1-21d BW and BWG of NC1+lipase),22-42d and1-42d F/G were decreased (P>0.10)(exclude1-42d F/G of NC2+lipase) in NC1+lipase, NC2+lipase and NC3+lipase;1-21d mortality of NC3+lipase was decreased (P<0.05).3) Lipase supplementation in NC1and NC2increased the BW and BWG of every stages to the level of PC, while in NC3+lipase the BW and BWG of every stages was lower than level of PC; in NC1+lipase the F/G of every stages was decreased to the level of PC, while in NC2+lipase and NC3+lipase the F/G of every stages was higher than the level of PC. There is no significant difference on slaughter performance in all groups (P>0.05). Two factorial analyze results showed that the reduction of AME tended to decrease the21d BW,1-21d BWG, and increase1-42d F/G or cull rate of1-21d (P<0.10) with siginificant effect on1-21d F/G (P<0.05). Lipase addition tended to increased42d BW,22-42d and1-42d BWG, abdominal fat rate (P<0.10). The interaction of AME and lipase siginificant affected the1-21d mortality, leg muscle rate (P<0.05).Experiment2:Effects of Lipase in Different Energy Levels Diets on Growth Performance and Digestive physiology in BroilersA total of660day-old Cobb commercial male broilers were randomly allocated into5treatments according to arandomized complete block design. Treatments included: positive control diet (PC,1-21d AME12.13MJ/kg,22-42d AME12.76MJ/kg), Two negative control diets:NC1(-210kJ/kg) and NC2(-420kJ/kg) with or without1000U/kg lipase. This experiment included two periods:starter (1-21days of age) and grower (22-42days of age) periods. The results showed as follows:1) Compared with the PC, there were no difference on BW of21d and BWG of1to22d in NCI and NC2, but BW of42d, BWG of1to22d and22to42d, AME were tended to decrease (P>0.10), F/G of every stages were tended to increase (P>0.10);42d relative weight of glandular stomach of NC1increased (P<0.10),42d relative weight of gizzard of NC1and NC2increased (P<0.05); there is no difference to relative length of every stages in all groups;42d crypt depth of duodenum in NC1increased (P<0.05); NCI and NC221d and42d crypt depth tended to increased (P<0.10),21d V/C decreased (P<0.05),21d villus diameter of NC2and42d villus diameter of NC1increased (P<0.05) in ileum.2) Compared with NC1or NC2negative controls, the BW, BWG of every stages, AME, utilization of GE, EE and DM were improved (P>0.10), F/G of every stages (exclude1-21d F/G of NC1+lipase) was decreased (P>0.10) to the level of PC in NCl+lipase and NC2+lipase;42d relative weight of gizzard was tended to decreased (P<0.10) in NC1+lipase and NC2+lipase but above the level of PC (P<0.05);42d crypt depth of duodenum was decreased in NC1+lipase (P<0.05); NC1+lipase and NC2+lipase21d crypt depth was tended to decreased (P<0.10),21d V/C was improved (21d V/C was significant improved (P<0.05) inNCl+lipase),but21d V/C below the level of PC (P<0.05),21d villus height above the level of PC (P<0.05) in NCl+lipase,42d V/C was tended to increased (P<0.10) but villus height was decreased in NCl+lipase (P<0.05) in ileum.Two factorial analyze results showed that the further decreased of AME tend to increased the cull rate of1-42d, rate of eviscerated yield, breast muscle,21d relative weight of caecum and relative length of duodenal,42d crypt depth of jejunum, decreased1-21d F/G,21d crypt depth of ileum,42d relative weight of gizzard and V/C of jejunum (P<0.10), significant increased villus diameter of42d jejunum and21d ileum(P<0.05), significant decreased42d villus height of duodenum,21d V/C of ileum(P<0.05). Lipase addition tended to increased the42d BW,22-42d BWG,1-42d BWG, rate of eviscerated yield with giblet, utilization of DM,21d villus height of duodenum and42d V/C of ileum(P<0.10), significant increased utilization of EE, villus height of jejunum,42d V/C of duodenum and ileum(P<0.05), siginificant decreased F/G of22-42d and1-42d,42d crypt depth of duodenum(P<0.05).The interaction of energy and lipase significant affected slaughter, rate of eviscerated yield with giblet,42d relative length and crypt depth or V/C of duodenum,42d V/C and villus diameter of ileum(P<0.05), tended to effected21d villus height of jejunum,42d villus diameter of duodenum and ileum,42d lipase activity of ileum(P<0.10).Experiment3:Responses of Lipase in Diets of Different Sources of Fats in BroilersA total of528day-old Cobb commercial male broilers were randomly allocated into4treatments according to arandomized complete block design. Treatments included:Animal-vegetable fat and Rapeseed oil with or without1000U/kg lipase. This experiment included two periods:starter (1-21days of age) and grower (22-42days of age) periods. The results showed as follows:1) There is no difference on BW, BWG, F/G, mortality, cull rate and relative weight of digestive tract or relative length of intestine of every stages in all groups (P>0.05).21d V/C of ileum in Rapeseed oil was improved to Animal-vegetable fat (P<0.05).2) Compared with Animal-vegetable fat or Rapeseed oil, BW and BWG of every stages, AME, utilization of GE and DM were improved (P>0.10), F/G of every stages were decreased (P>0.10) in Animal-vegetable fat+lipase and Rapeseed oil+lipase, utilization of EE was improved (P>0.10) in Animal-vegetable fat+lipase; duodenal:21d crypt depth was tended to increased (P<0.10) in Animal-vegetable fat+lipase and Rapeseed oil+lipase,42d crypt depth was significant decreased in Animal-vegetable fat+lipase,but no difference on21d and42d V/C; ileum:21d and42d V/C were improved (P<0.05),42d villus diameter was decreased (P<0.05) in Animal-vegetable fat+lipase, but there is no difference on intestine morphology in Rapeseed oil+lipase (P>0.05).3) There is no difference on1-21d BW, BWG and F/G between Animal-vegetable fat+lipase and Rapeseed oil+lipase, but improvement of22-42d and1-42d BW, BWG, F/G, AME, utilization of EE, morphology of duodenal and ileum, lipase activity in intestine of every stages in Animal-vegetable fat+lipase above the level of Rapeseed oil+lipase.Two factorial analyze results showed that animal-vegetable fat tended to increased utilization of DM,42d relative weight of pancreas (P<0.10), decreased42d relative length of duodenum,42d V/C of jejunum and ileum (P<0.10), significant decreased42d relative length of caecum, villus diameter of42d duodenum and jejunum or21d ileum (P<0.05). Lipase addition tended to increased utilization of DM,21d villus height of duodenum and jejunum (P<0.10), decreased42d relative weight of jejunum (P<0.10), siginificant increased42d V/C of ileum,21d lipase activity of ileum (P<0.05), significant decreased crypt depth of21d and42d duodenum,42d villus diameter of ileum (P<0.05). The interaction of energy and lipase significant affected21relative weight and villus height of jejunum,21d crypt depth and V/C of ileum,42d V/C of duodenum,42d villus height and V/C of ileum (P<0.05), tended to effected42d relative weight of pancreas, crypt depth of duodenum (P<0.10).Result suggest that the lipase supplementation in diet at1000U/kg could effectively alleviated the negative effects with the reduction of AME210kJ/kg; The improvement of lipase in mixed oil with animal-vegetable fat was better than in rapeseed oil in equal AME diets. |
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