近来发现蛋白质的消化产物在动物肠道内有相当一部分是以小肽的形式吸收和利用。克隆和分析两个结构相似的小肽转运载体 (Pep T1和 Pep T2 )揭示了哺乳动物和禽类的小肽转运机制。这些小肽转运载体识别二肽和三肽 ,其活性受日粮蛋白质...近来发现蛋白质的消化产物在动物肠道内有相当一部分是以小肽的形式吸收和利用。克隆和分析两个结构相似的小肽转运载体 (Pep T1和 Pep T2 )揭示了哺乳动物和禽类的小肽转运机制。这些小肽转运载体识别二肽和三肽 ,其活性受日粮蛋白质水平和各种激素的调控。目前对人、猪、鸡、大鼠、小鼠、兔子、绵羊等的 Pep T1的基因结构和蛋白质结构已有了系统的认识。就其生理特性、分布。展开更多
Background: This study evaluated the effects of Eimeria spp. challenge and dietary supplementation with free methionine or methionine dipeptide on animal performance;expression of genes associated with the immune syst...Background: This study evaluated the effects of Eimeria spp. challenge and dietary supplementation with free methionine or methionine dipeptide on animal performance;expression of genes associated with the immune system, antioxidant system, and amino acid transport in the jejunum;and redox status of the jejunum of broiler chickens.Methods: A randomized, 2 × 3 factorial design was used, in which Eimeria spp. challenge was the first factor(Eimeria-challenged, EC, or unchallenged, UC, broilers) and methionine supplementation was the second factor(non-supplemented, NS;free DL-methionine, DL-Met;and methionine dipeptide, DL-methionyl-DL-methionine, DLMMet). At 14 days of age, chickens were inoculated orally with sporulated oocysts of Eimeria acervulina, Eimeria praecox, Eimeria maxima, and Eimeria mitis. Birds were killed by cervical dislocation 144 h post-inoculation(PI), and the jejunum was collected for biochemical and molecular analyses.Results: EC broilers had a 13% lower feed intake(FI), 37% lower body weight gain(BWG), and 39% higher feed conversion ratio(FCR) than UC broilers. Chickens fed the DL-Met diet had higher BWG(about 12% higher) and better FCR(about 12% lower) than chickens fed the NS diet. EC chickens had lower relative weight of the bursa of Fabricius(51.8%) and higher relative weights of the spleen and whole intestine(53.6% and 26.3%, respectively) than UC chickens. Eimeria spp. challenge led to an increase in the levels of oxidative substances, such as nitrite and thiobarbituric acid reactive substances(TBARS), in the jejunum of chickens 144 h PI. Among UC chickens, those fed the DL-Met diet had higher total antioxidant capacity(TAC) and lower catalase(CAT) and superoxide dismutase(SOD) activities. EC chickens that received the NS diet had higher carbonylated protein content(CP). This result was associated with their lower TAC and catalase activity. The lower TAC in EC chickens might have been due to reduced expression of catalase(CAT) and superoxide dismutase 1(SOD1) genes. Chickens fed the DL-M展开更多
文摘近来发现蛋白质的消化产物在动物肠道内有相当一部分是以小肽的形式吸收和利用。克隆和分析两个结构相似的小肽转运载体 (Pep T1和 Pep T2 )揭示了哺乳动物和禽类的小肽转运机制。这些小肽转运载体识别二肽和三肽 ,其活性受日粮蛋白质水平和各种激素的调控。目前对人、猪、鸡、大鼠、小鼠、兔子、绵羊等的 Pep T1的基因结构和蛋白质结构已有了系统的认识。就其生理特性、分布。
基金funded by the National Council of Technological and Scientific Development(CNPq)Brazil(Project no.445322/2014–4)
文摘Background: This study evaluated the effects of Eimeria spp. challenge and dietary supplementation with free methionine or methionine dipeptide on animal performance;expression of genes associated with the immune system, antioxidant system, and amino acid transport in the jejunum;and redox status of the jejunum of broiler chickens.Methods: A randomized, 2 × 3 factorial design was used, in which Eimeria spp. challenge was the first factor(Eimeria-challenged, EC, or unchallenged, UC, broilers) and methionine supplementation was the second factor(non-supplemented, NS;free DL-methionine, DL-Met;and methionine dipeptide, DL-methionyl-DL-methionine, DLMMet). At 14 days of age, chickens were inoculated orally with sporulated oocysts of Eimeria acervulina, Eimeria praecox, Eimeria maxima, and Eimeria mitis. Birds were killed by cervical dislocation 144 h post-inoculation(PI), and the jejunum was collected for biochemical and molecular analyses.Results: EC broilers had a 13% lower feed intake(FI), 37% lower body weight gain(BWG), and 39% higher feed conversion ratio(FCR) than UC broilers. Chickens fed the DL-Met diet had higher BWG(about 12% higher) and better FCR(about 12% lower) than chickens fed the NS diet. EC chickens had lower relative weight of the bursa of Fabricius(51.8%) and higher relative weights of the spleen and whole intestine(53.6% and 26.3%, respectively) than UC chickens. Eimeria spp. challenge led to an increase in the levels of oxidative substances, such as nitrite and thiobarbituric acid reactive substances(TBARS), in the jejunum of chickens 144 h PI. Among UC chickens, those fed the DL-Met diet had higher total antioxidant capacity(TAC) and lower catalase(CAT) and superoxide dismutase(SOD) activities. EC chickens that received the NS diet had higher carbonylated protein content(CP). This result was associated with their lower TAC and catalase activity. The lower TAC in EC chickens might have been due to reduced expression of catalase(CAT) and superoxide dismutase 1(SOD1) genes. Chickens fed the DL-M
