【作者】 聂伟；

【导师】 呙于明；

【作者基本信息】 中国农业大学 ， 动物营养与饲料科学， 2013， 博士

【摘要】 本文通过以下试验,系统地研究了日粮不同磷水平对蛋鸡生产性能、钙磷吸收和免疫应激的影响,并确定了矮小型粉壳蛋鸡日粮中磷适宜供给量。试验一以玉米-豆粕型为基础日粮,配制设计含5个非植酸磷水平日粮,日粮其他营养水平一致。选用体重相近的28周龄矮小粉壳蛋鸡405只,随机分为9组,每组9个重复。研究日粮非植酸磷水平对30-41周龄产蛋高峰期矮小粉壳蛋鸡,50-61周龄产蛋中后期矮小粉壳蛋鸡生产性能、蛋品质及钙磷吸收相关基因表达的影响。试验结果如下：30-41周龄矮小粉壳蛋鸡代谢能2.70Mcal/kg和粗蛋白17%日粮中,非植酸磷水平推荐剂量为0.30%；50-61周龄蛋鸡代谢能2.60Mcal/kg和粗蛋白15.8%日粮中,非植酸磷水平推荐剂量为0.20%。随着日粮非植酸磷水平增加,60周龄蛋鸡ConA刺激指数呈先升高后降低的二次曲线关系,非植酸磷为0.28%组蛋鸡ConA刺激指数最高。蛋鸡十二指肠Napi-IIb mRNA表达量41周龄显著低于30周龄,十二指肠CaBP mRNA表达量41周龄显著高于30周龄。日粮中非植酸磷水平的提高,41周龄蛋鸡十二指肠肠道Napi-IIb mRNA表达量线性降低,肾脏Napi-IIa mRNA表达量线性升高。日粮中非植酸磷水平的提高,41周龄蛋鸡十二指肠CaBP mRNA的表达量和蛋白表达量呈先升高后降低二次曲线关系,日粮非植酸磷水平为0.25%和0.30%达到最大值。结果表明,随着蛋鸡周龄的增长,蛋鸡对非植酸磷的需求量降低,十二指肠Napi-IIb mRNA下降；蛋鸡对钙的需求量升高,十二指肠CaBP mRNA表达量升高。试验二采用2x3因子安排的随机试验设计,两个多维水平和0.20%、0.30%和0.40%三个非植酸磷水平,以玉米-豆粕型为基础日粮,日粮其他营养水平一致。随机分为6个处理,每个处理5个重复,每个重复15只鸡,共450只蛋鸡。研究日粮非植酸磷和多维水平对矮小粉壳蛋鸡蛋壳品质和暗斑蛋壳的影响。试验结果如下：饲喂低多维水平和0.30%非植酸磷日粮,蛋鸡产蛋率最高。日粮非植酸磷和多维水平的增加也显著加深了蛋壳色泽。日粮非植酸磷水平的提高显著升高了蛋鸡血清磷含量,降低了血清钙的含量。提高多维水平增加了蛋鸡血清中白蛋白含量,降低了血清中ALP含量。日粮非植酸磷和多维水平对蛋鸡血清磷和T-SOD含量的影响有显著互作效应。暗斑蛋壳组外层钙元素相对含量、内膜磷元素相对含量和蛋壳中钙含量显著低于无斑蛋组。暗斑蛋壳组壳膜厚度、内膜及三层总厚度极显著低于无斑蛋壳组。产暗斑蛋的蛋鸡血清中丙二醛(MDA)显著升高。产暗斑蛋的蛋鸡子宫CaBP mRNA和Ca2+-ATPase mRNA表达量显著低于正常蛋鸡。结果表明暗斑蛋壳的产生与钙磷代谢密切相关,蛋壳乳突层有效厚度对蛋壳质量有重要影响。0.4%非植酸磷日粮降低了蛋鸡暗斑蛋的发生率。试验三以玉米-豆粕型为基础日粮,配制设计0.12%和0.40%两种非植酸磷水平日粮,日粮其他营养水平一致。试验采用28周龄体况良好体重相近的蛋鸡300只,随机分为2个组,每组设10个重复,每个重复15只鸡。预饲期为4周,试验期为5周。预饲期结束后32周龄时,每组半数(5个重复)的蛋鸡隔天(第1、3、5、7、9)腹腔注射脂多糖(注射剂量为1.5mg/kg),剩余半数(5个重复)注射相同剂量的生理盐水。研究不同磷营养状态下免疫应激对蛋鸡产蛋性能和蛋品质等影响。与生理盐水组相比,脂多糖注射3小时后脂多糖组蛋鸡直肠温度显著增高,脂多糖组采食量和产蛋率显著下降,料蛋比显著增加。脂多糖诱导的免疫应激显著增加了鸡蛋的蛋壳厚度,增强了蛋壳强度,同时增加了蛋白高度和哈氏单位。非植酸磷水平和脂多糖对蛋壳和蛋黄色泽有极显著的互作效应。显著提高蛋壳和胫骨中钙和磷的含量。脂多糖诱导的免疫应激降低了血清钙、磷和超氧化物歧化酶含量,提高了血清中丙二醛(MDA)、白介素-1β (IL-1β)和白介素-6(IL-6)含量,脂多糖处理组蛋鸡肝脏和脾脏占蛋鸡体重比率显著高于生理盐水处理组。脂多糖诱导的免疫应激显著提高了盲肠扁桃体IL-1p和IL-6mRNA表达水平,导致蛋鸡生产性能下降,小肠绒毛结构损伤。随着日粮磷水平升高,蛋鸡血清中MDA含量降低,Y干扰素(IFN-γ)含量增加,增加了绒毛高度与隐窝深度的比值,减轻肠道损伤,增强机体的免疫机能。本研究表明30-41周龄矮小粉壳蛋鸡日粮中代谢能2.70Mcal/kg和粗蛋白17%,非植酸磷水平推荐剂量为0.30%,50-61周龄日粮中代谢能2.60Mcal/kg和粗蛋白15.8%,非植酸磷水平推荐剂量为0.20%。随着蛋鸡周龄的增长,蛋鸡对非植酸磷的需求量降低,对钙的需求量增加。暗斑蛋壳组外层钙元素相对含量、内膜磷元素相对含量和蛋壳中钙含量显著低于无斑蛋组。产暗斑蛋的蛋鸡子宫CaBP mRNA和Ca2+-ATPase mRNA表达量低于正常蛋鸡；暗斑蛋壳的产生与钙磷代谢密切相关。脂多糖诱导的免疫应激导致蛋鸡生产性能下降,小肠绒毛结构损伤,日粮磷水平增加可以减轻肠道损伤,增加血清中γ干扰素含量,增强了机体的免疫机能。更多还原

【Abstract】 In order to systemically investigate the effect of different levels of dietary phosphorus on the production performance, metabolism of calcium and phosphorus and immunity stress in layers, and determine phosphorus supply in the dwarf layers of dietaryExperiment1:The corn-soybean meal with5levels of non-phytate phosphorus (NPP) were used. A total of405pink-shell dwarf layers aged at28weeks were randomly divided into9treatments with9replicates each. Production performance at and after peak production, egg quality and expression of genes related to calcium and phosphorus were investigated. Dietary NPP of0.3%could meet the requirement for the peak egg production (30-40weeks of age), while NPP of0.2%was sufficient for the production performance of layers aged at50-61weeks. With the increment in dietary NPP, the ConA stimulation index displayed a quadratic relationship with the highest level at0.28%of dietary NPP. At41weeks of age, with the increase in dietary NPP, the Nap Ⅱb mRNA abundance in duodenum decreased linearly, while kidney Nap Ⅱa mRNA increased linearly. The levels of CaBP mRNA and protein expression showed a quadratic relationship with dietary NPP with highest expression at the0.25%and0.30%of NPP, respectively. Those results suggested that the requirement of NPP decreased, but calcium requirement increased in aged birds. In accordance, the expression of Nap Ⅱb mRNA and CaBP mRNA decreased and increased in the duodenum.Experiment2:The2*3factorial experimental design was adopted with2levels of multi-vitamin supplements and3levels of dietary NPP (0.2%,0.3%and0.4%) in the corn-soybean meal. A total of450layers has been randomly divided to5treatments with5repeats each treatment of15birds each. Egg production and egg quality were investigated. Highest egg production was observed when0.3%of NPP were supplemented in the diet containing low level of multi-vitamin. The eggshell color was darken with the increment in dietary NPP and multi-vitamin. Dietary NPP significantly increased serum phosphorus but decreased serum calcium content. Multi-vitamin supplements increased the serum albumin and decreased serum ALP. There were interactions on serum phosphorus and T-SOD activity between dietary NPP and multi-vitamin. Compared with unspotted eggs, the thickness of eggshell and the membrane was thinner in spotted eggs. The contents of phosphorus and calcium were lowered in the inner membrane and the outer membrane of spotted eggshell, respectively. In layers producing spotted eggs, uterus CaBP mRNA and Ca2+-ATPase mRNA expression was lower than normal hens; in contrast, serum MDA was higher. The results suggested calcium and phosphorus metabolism closely related with the formation of spotted eggs. The eggshell and membrane thickness positively correlated with the spots formation and the effective thickness of papillary layer has a determinative role in eggshell quality. Dietary NPP of0.4%decreased the ratio of spotted eggs.Experiment3:The layer were fed either0.12%or0.4%dietary NPP in corn-soybean meal. A total of300healthy layers aged28weeks old has been randomly divided to2dietary treatment groups with10repeats each treatment of15birds each. All bird were prefed for4weeks and the trial lasted for5weeks. At the age of32weeks, half birds of each dietary treatment received LPS or saline administration ip on every the other day for9days. Egg production and egg quality were determined when immunologically stressed those layers. Administration of LPS elevated the rectal temperature after3hours and significantly decreased feed intake and egg production. LPS-induced immune stress significantly increased eggshell thickness, strength, albumin height and Haugh unit. There was a significant interaction between dietary NPP and LPS treatment. LPS-induced immune stress lowered serum calcium, phosphorus, total protein, albumin, globulin and SOD activities, but increased MDA, IL-1β and IL-6in the serum. Layers received LPS had higher relative weight of liver and spleen than those received saline. LPS stimulation significantly increased cecum IL-1β, IL-6and IL-10mRNA expression. LPS administration also damaged the architecture of intestine villi, decreased the ratio of villi height/crypt depth and dampened the crypt. Dietary phosphorus significantly increased the ratio of villi height/crypt depth, decreased serum MDA and IFN-y and alleviated the damage in the intestine.In conclusion, the recommended dietary NPP for pink-shell dwarf layers were0.3%and0.2%at the peak production and after the peak production, respectively. The requirement for NPP and calcium decreased and increased in aged layers, respectively. The CaBP mRNA abundance in the uterus was lower in birds producing spotted eggs than normal birds, indicating the close relationship between the formation of spotted eggshell and metabolism of calcium and phosphorus. The eggshell and membrane thickness positively correlated with the spots formation. LPS-induced immune stress significantly decreased egg production and damaged the architecture of intestine villi and high level of dietary NPP could alleviate the damage by elevating serum IFN-y.更多还原