Trevisi P, Corrent E, Mazzoni M, Messori S, Priori D, Gherpelli Y, Simongiovanni A, Bosi P
DISTAL, University of Bologna, Reggio Emilia, Italy.
J Anim Physiol Anim Nutr (Berl). 2015 Jun;99(3):511-20. doi: 10.1111/jpn.12216. Epub 2014 Jun 26.
Threonine (Thr) is important for mucin and immunoglobulin production. We studied the effect of added dietary Thr on growth performance, health, immunity and gastrointestinal function of weaning pigs with differing genetic susceptibility to E. coli K88ac (ETEC) infection and challenged with ETEC. Forty-eight 24-day-old weaned pigs were divided into two groups by their ETEC susceptibility using mucin 4 (MUC4) gene as a marker (2 MUC4(-/-) , not-susceptible, and 2 MUC4(+/+) , susceptible, pigs per litter). Within genotype, pigs were fed two different diets: 8.5 (LThr) or 9.0 (HThr) g Thr/kg. Pigs were orally challenged on day 7 after weaning and slaughtered on day 12 or 13 after weaning. Before ETEC challenge, HThr pigs ate more (p < 0.05). The diet did not affect post-challenge growth, but HThr tended to increase post-challenge feed efficiency (p = 0.087) and overall growth (p = 0.087) and feed efficiency (p = 0.055). Before challenge, HThr pigs excreted less E. coli (p < 0.05), while after challenge, diet did not affect the number of days with diarrhoea and ETEC excretion. MUC4(+/+) pigs responded to the challenge with more diarrhoea, ETEC excretion and anti-K88 IgA in blood and jejunal secretion (p < 0.001). HThr pigs had a higher increase of anti-K88 IgA values in jejunal secretion (p = 0.089) and in blood (p = 0.089, in MUC4(+/+) pigs only). Thr did not affect total IgA and IgM values, morphometry of jejunum, goblet cells count in colon, total mucin from jejunum and colon, but varied jejunal goblet cells counts (p < 0.05). In the first two post-weaning weeks, 8.5 g Thr/kg diet may be not sufficient to optimize initial feed intake, overall feed efficiency and intestinal IgA secretion and to control the gut microbiota in the first post-weaning week, irrespective of the pig genetic susceptibility to ETEC infection.
苏氨酸（Thr）对黏蛋白和免疫球蛋白的产生很重要。我们研究了在日粮中添加苏氨酸对不同遗传易感性的断奶仔猪生长性能、健康状况、免疫力和胃肠功能的影响，这些仔猪用产肠毒素大肠杆菌K88ac（ETEC）进行攻毒。48头24日龄断奶仔猪以黏蛋白4（MUC4）基因作为标记，根据其对ETEC的易感性分为两组（每窝2头MUC4（-/-）不易感仔猪和2头MUC4（+/+）易感仔猪）。在每种基因型内，仔猪饲喂两种不同日粮：含8.5（低苏氨酸，LThr）或9.0（高苏氨酸，HThr）克苏氨酸/千克。仔猪在断奶后第7天进行口服攻毒，并在断奶后第12天或第13天屠宰。在ETEC攻毒前，高苏氨酸日粮组仔猪采食量更多（p<0.05）。日粮对攻毒后的生长没有影响，但高苏氨酸日粮组倾向于提高攻毒后的饲料效率（p=0.087）、总体生长性能（p=0.087）和饲料效率（p=0.055）。攻毒前，高苏氨酸日粮组仔猪排出的大肠杆菌较少（p<0.05），而攻毒后，日粮对腹泻天数和ETEC排泄量没有影响。MUC4（+/+）仔猪攻毒后的腹泻、ETEC排泄以及血液和空肠分泌物中的抗K88 IgA更多（p<0.001）。高苏氨酸日粮组仔猪空肠分泌物中抗K88 IgA值升高幅度更大（p=0.089），血液中抗K88 IgA值升高幅度更大（仅在MUC4（+/+）仔猪中p=0.089）。苏氨酸不影响总IgA和IgM值、空肠形态计量学、结肠杯状细胞计数、空肠和结肠的总黏蛋白，但空肠杯状细胞计数有所不同（p<0.05）。在断奶后的前两周内，无论仔猪对ETEC感染的遗传易感性如何，8.5克苏氨酸/千克的日粮可能不足以优化初始采食量、总体饲料效率和肠道IgA分泌，也不足以在断奶后的第一周控制肠道微生物群。
