Studies On Growth-Promoting Function And Mechanisms Of Cysteamine, Methylsulfonylmethane And Natural Plant Extracts In Meat-type Ducks

In this study,four experiments were designed to comparatively investigate whether exogenous metabolism-regulatory substances(natural plant extracts,cysteamine and methylsulfonylmethane) possess growth promoting effects and the mechanisms in finishing meat-type ducks.Experiment 1 A one-factor experiment was designed to investigate the effects of natural plant extracts(PE)(a mixture of aqueous and ethanobic extracts from American ginseng,Radix Astragali,Glycyrrhiza,Rhizama Atractylodis Macrocephalae,massa medicata fermentata and Lycium Chinense Mill.),cysteamine(CS) and methylsulfonylmethane(MSM) on growth performance,dressing performance,nutrient utilization efficiency,hormone level and blood biochemical indexes in meat-type ducks.264 healthy d 14 Tian-Fu meat-type ducks weighing 660±11g with similar consanguinity were chosen and allotted randomly to 11 treatments,4 replicates in each treatment and 6 ducks per replicate(3 males and 3 females). The basal experimental diet was corn and soya bean meal containing 2.9Mcal ME/kg and 18%CP.Ducks were fed basal diet,basal diet+250mg/kg CS,basal diet+500mg/kg CS,basal diet+750mg/kg CS,basal diet+250mg/kg MSM,basal diet+500mg/kg MSM,basal diet+1000mg/kg MSM,basal diet+500mg/kg PE,basal diet+1000mg/kg PE,basal diet+2000mg/kg PE,basal diet+3000mg/kg PE,respectively.The growth experiment lasted for 28 days.When the growth experiment finished,the slaughter and metabolism experiment were implemented.The metabolism experiment lasted for 7days.The results showed that:1.PE,CS and MSM increased weight gain rate and feed utilization efficiency in finishing meat-type ducks.The effects of PE on prductive performance were much greater than CS and MSM.Compared with the control group,PE,CS and MSM increased ADG by 7.05%,2.80%and 1.88%;decreased F/G by 9.67%,2.43%and 2.68%;increased DM availability by 7.99%,2.33%和4.27%;increased CP availability by 8.38%,8.16%and 15.24%;increased energy availability by 5.93%,1.28%and 3.99%respectively.2.PE,CS and MSM improved slaughter characteristics,the effects of PE were much obvious.Compared with the control group,PE,CS and MSM increased lean meat ratio by 16.37%(P<0.05),0.84%and 2.70%;decreased abdominal fat deposition by 25.19% (P<0.01),11.41 and 13.69%respectively.3.The effects of PE on growth performance and slaughter characteristics exist significant dose-effect relationship in finishing meat-type ducks(P<0.01 or P<0.05).CS and MSM didn't exist significant dose-effect relationship.4.Different levels of CS,MSM and PE improved immune organ index.Compared with the control group,CS,MSM and PE increased the total index by 6.02%-12.65%(P<0.05), 2.26%-8.73%,1.05%-13.55%(P<0.05).2000mg/kg PE significantly increased IgG,IgA and IgM by 33.95%(P<0.05),11.74%(P<0.05) and 25.75%(P<0.05).5.The effects of PE on blood biochemical indexes were much greater than CS and MSM. Compared with the control group,CS,MSM and PE increased TP by 1.37%,0.14%and 7.69%;influenced fat metabolism,decreased TG by 20.79%,31.90%and 40.32%;decreased TCH by 20.70%,16.58%and 28.10%;decreased VLDL-C by 25.40%,39.68%and 45.24%; increased LDH by 13.78%,10.30%and 22.645;increased AKP by 23.29%,23.33%and 17.52%;decreased BU by 9.19%,8.67 and 12.39%;improved protein metabolism, decreased UA by 29.29%,28.97%and 33.21%;increased CREA by 6.72%,4.77%and 5.43%respectively;had no significant effects on CK,ALT and AST.6.Dietary supplementation of different levels of CS,MSM and PE increased GH and INS levels:Compared with the control group,increased GH by GH 7.89%-22.81%, 1.75%-29.82%,28.07%-47.37%(P<0.05);increased INS by 9.15%-45.53%(P<0.05), 17.17%-42.07%(P<0.05),8.43%-46.95%(P<0.05) respectively.7.Different levels of CS,MSM and PE increased antioxidative capacity of meat-type ducks:Compared with the control group,increased by T-AOC7.87%,6.37%,16.08%, 9.72%,13.07%,4.36%,22.45%,26.80%,40.70%(P<0.05)and 13.07%;decreased MDA by 25.24%(P<0.05),18.56%(P<0.05),26.19%(P<0.05),2.65%,27.36%(P<0.05), 23.12%(P<0.05),21.95%(P<0.05),9.33,52.60%(P<0.01) and 11.98%respectively.Experiment 2 The effects of PE,CS and MSM on expression of PPAR-γmRNA in duck spleen was investigated in Experiment 2.The experimental design and the feeding management were the same as Experiment 1.The results showed that:1 CS,MSM and PE increased expression of PPAR-γmRNA.Compared with the control group,CS,MSM and PE increased expression of PPAR-γmRNA by 31.33%,65.91%and 199.06%respectively.2 The regression analysis showed that,dietary supplementation of PE and MSM had quadratic effects(P<0.05) on PPAR-γmRNA.With the increasing of supplemental dosage of CS,PPAR-γmRNA increased linearly(P<0.05).Experiment 3 A 3×6 factor experiment was conducted to investigate the effects of PE, CS and MSM on peripheral blood lymphocyte proliferation and signal transduction in meat-type ducks.The results showed that:1 Compared with the control group,CS,MSM and PE increased peripheral blood lymphocyte(PBL) proliferation by 19.45%,16.97%and 28.41%respectively.CS,MSM and PE had quadratic effects(P<0.05) on PBL proliferation.2 Compared with the control group,CS,MSM and PE increased IL-1 level in the peripheral blood lymphocyte culture fluid by 35.12%,25.86%and 41.87%;decreased IL-6 by 35.61%,41.38%and 47.11%respectively;CS,MSM and PE had quadratic effects(P<0.05) on IL-1 and IL-6 levels.3 Compared with the control group,CS,MSM and PE decreased NO by 9.26%,4.94% and 11.42%;decreased NOS by 2.67%,2.31%and 7.33%;decreased iNOS by 6.59%,6.95% and 17.37%respectively.PE had quadratic effects(P<0.05) on NO and iNOS.4 Compared with the control group,CS,MSM and PE tended to increase cAMP in the peripheral blood lymphocyte culture fluid by 0.32%,2.59%and 5.18%respectively; increased cGMP by 81.11%,65%and 92.22%;decreased cAMP/cGMP by 39.188%,31.34% and 39.77%respectively.CS,MSM and PE had quadratic effects(P<0.05) on cAMP,cGMP and cAMP/cGMP.The above results showed that,the effects of PE were larger than CS and MSM. The following conclusions could be drawn from all the above results:1 The effects of PE on growth performance and slaughter characteristics were larger than CS and MSM.PE had quadratic effects(P<0.05 or P<0.01) on growth performance and slaughter characteristics.CS and MSM had no dose-effects.2 PE,CS and MSM could improve immune organ development,increase humoral immunity level and peripheral blood lymphocyte proliferation,decrease iNOS activity and NO level and increase cGMP level in the lymphocyte culture fluid.The effects of PE were larger than CS and MSM.3 The effects of PE on antioxidative capacity were much greater than CS and MSM.4 CS,MSM and PE increased expression of PPAR-γmRNA.The effects of PE were larger than CS and MSM.PE and MSM had quadratic effects(P<0.05) on PPAR-γmRNA. With the increasing of supplemental dosage of CS,PPAR-γmRNA increased linearly (P<0.05).5 PE,CS and MSM improved growth rate of meat-type ducks through improving immunity and antioxidative capacity,through decreasing iNOS activity,decrease NO level, stimulate GC,increase cGMP level and modulate immune functions.