Munoz Alfonso Cristhiam Jhoseph, Kozole Cierra, Htoo John Kyaw, Huber Lee-Anne
University of Guelph, Guelph, ON, Canada N1G 2W1.
Evonik Operations GmbH, Hanau-Wolfgang, Germany.
J Anim Sci. 2025 Jan 4;103. doi: 10.1093/jas/skaf156.
A total of 70 gestating gilts (166 ± 13 kg initial BW on day 31 of gestation) were used to determine the standardized ileal digestible (SID) Met needed to maximize whole-body N retention and to describe the impact of dietary Met on indicators of Met utilization for roles beyond protein synthesis. Seven days prior to N balance measurements between days 38 and 41, days 53 and 56, days 87 and 90, and days 109 and 112 of gestation (periods 1, 2, 3, and 4, respectively), gilts were assigned to 1 of 7 dietary treatments (n = 10) that titrated SID Met between 50% and 150% of perceived requirements of 3.5 and 5.2 g SID Met/d (before and after day 90 of gestation, respectively) using dl-Met and in the presence of excess Cys in an incomplete randomized block design. Fasted blood samples were collected on days 38, 53, 87, and 109 to assess concentrations of plasma Met-derived metabolites. Contrast statements were used to determine linear and quadratic effects of the dietary inclusion level of SID Met and quadratic polynomial (QPM), broken-line linear, and broken-line quadratic (BLQ) ascending models were evaluated for the primary response variables. Whole-body N retention did not exhibit linear or quadratic relationships with increasing SID Met content in periods 1, 2 and 3, but inflection points were observed at 0.17% (3.8 g SID Met/d; QPM), 0.19% (4.2 g SID Met/d; BLQ), and 0.16% SID Met (3.5 g SID Met/d; QPM), respectively. Whole-body N retention increased (linear and quadratic; P < 0.001) with increasing SID Met content in period 4, optimized at 0.23% (6.0 g SID Met/d; QPM). Plasma creatine concentration did not exhibit linear or quadric relationships with increasing SID Met contents, but the QPM indicated inflection points at 0.17%, 0.17%, 0.22%, and 0.18% SID Met (3.8, 3.8, 4.9, and 4.7 g SID Met/d) on gestation days 38, 53, 87, and 109, respectively. Plasma concentrations of GSH tended to increase then decrease (quadratic; P = 0.096) on day 53 and tended to increase (linear; P = 0.095) on day 87 as SID Met increased; inflection points were observed at 0.16%, 0.17%, 0.21%, and 0.16% SID Met (3.5, 3.8, 4.6, and 4.2 g/d; QPM) on gestation days 38, 53, 87, and 109, respectively. Thus, the SID Met feeding recommendations provided by the NRC (NRC 2012. Nutrient requirements of swine. 11th rev ed. Washington D.C.: National Academy Press) gestating sow model are insufficient to maximize whole-body N retention of gilts throughout gestation in current production conditions, while the supply of SID Met might also influence Met utilization for metabolic fates beyond protein retention.
选用70头妊娠后备母猪（妊娠第31天初始体重166±13 kg）来确定使全身氮保留最大化所需的标准回肠可消化蛋氨酸（SID Met），并描述日粮蛋氨酸对蛋白质合成以外蛋氨酸利用指标的影响。在妊娠第38至41天、53至56天、87至90天和109至112天（分别为时期1、2、3和4）进行氮平衡测定前7天，将后备母猪分配到7种日粮处理中的1种（n = 10），采用dl-蛋氨酸，在不完全随机区组设计中，在半胱氨酸过量的情况下，将SID Met在妊娠90天之前和之后分别设定为预计需求量3.5和5.2 g SID Met/d的50%至150%之间进行滴定。在妊娠第38、53、87和109天采集空腹血样，以评估血浆蛋氨酸衍生代谢物的浓度。使用对比语句来确定日粮中SID Met添加水平的线性和二次效应，并对主要反应变量评估二次多项式（QPM）、折线线性和折线二次（BLQ）上升模型。在时期1、2和3，全身氮保留与增加的SID Met含量之间未呈现线性或二次关系，但分别在0.17%（3.8 g SID Met/d；QPM）、0.19%（4.2 g SID Met/d；BLQ）和0.16% SID Met（3.5 g SID Met/d；QPM）处观察到拐点。在时期4，全身氮保留随SID Met含量增加而增加（线性和二次；P < 0.001），在0.23%（6.0 g SID Met/d；QPM）时达到最佳。血浆肌酸浓度与增加的SID Met含量之间未呈现线性或二次关系，但QPM表明在妊娠第38、53、87和109天分别在0.17%、0.17%、0.22%和0.18% SID Met（3.8、3.8、4.9和4.7 g SID Met/d）处出现拐点。随着SID Met增加，血浆谷胱甘肽浓度在第53天呈先升高后降低趋势（二次；P = 0.096），在第87天呈升高趋势（线性；P = 0.095）；在妊娠第38、53、87和109天分别在0.16%、0.17%、0.21%和0.16% SID Met（3.5、3.8、4.6和4.2 g/d；QPM）处观察到拐点。因此，美国国家研究委员会（NRC，2012年。猪的营养需求。第11版修订版。华盛顿特区：美国国家科学院出版社）妊娠母猪模型提供的SID Met饲喂建议不足以在当前生产条件下使妊娠后备母猪在整个妊娠期的全身氮保留最大化，同时SID Met的供应也可能影响蛋白质保留以外代谢途径的蛋氨酸利用。
