Effect of added dietary threonine on growth performance, health, immunity and gastrointestinal function of weaning pigs with differing genetic susceptibility to Escherichia coli infection and challenged with E. coli K88ac

Abstract

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.

Goblet cells and mucus layer in the gut of young pigs: Response to dietary contents of threonine and non‐essential amino acids

“…The present study did not show a negative influence of low dietary Thr level on the number of GC containing all mucin types and adherent mucus layer thickness in the gut of young pigs. These results are consistent with the studies of Hamard, Sève, and Le Floc'h () and Trevisi et al (), who observed that the total number of GC in the jejunum, ileum and colon in weaned piglets was not affected by moderate and low Thr deficiencies (70% and 94% of Thr requirement respectively). A study of Plitzner, Ettle, Handl, Schmidt, and Windisch () also found no effect of a low Thr deficiency (90% of Thr requirement) on the GC number in the small intestine and colon in finishing pigs.…”

“…The present study did not show a negative influence of low dietary Thr level on the number of GC containing all mucin types and adherent mucus layer thickness in the gut of young pigs. These results are consistent with the studies of Hamard, Sève, and Le Floc'h (2007) and Trevisi et al (2015), who observed that the total number of GC and Qiao (2010), who fed diets with a higher Thr deficiency (50% and 17% of Thr requirement, respectively), also resulted in a lower number of GC containing acidic mucins in the duodenum and ileum in early-weaned piglets respectively. The reduction of GC containing acidic mucins in the ileum of piglets fed diets covering 50% of Thr requirement was accompanied by a lower protein synthesis in the jejunal mucosa and mucins (Wang et al, 2007).…”

Effect of feed supplementation with live yeast on the intestinal transcriptome profile of weaning pigs orally challenged with Escherichia coli F4

“…The base diet -better detailed in Trevisi et al (2015a) was based on wheat shorts, corn, barley, extruded barley, soybean meal 50, whey dehydrated and skimmed, potato, protein concentrate, vegetable oil, dehydrated beet pulp, calcium carbonate, monosodium phosphate hydrated, sodium chloride, vitamin and trace mineral mixture, and was integrated with 0.4% L-lysine HCl, 0.2% DL-methionine, 0.15% L-threonine, 0.07% L-tryptophan. The colistin (Sintofarm, Guastalla, Reggio Emilia, Italy) treatment was used as a positive control owing to its activity against the ETEC strain used for the challenge, following a procedure frequently used for this purpose in other trials involving an ETEC challenge (Trevisi et al, 2015b). The pigs were individually penned in cages, kept at a controlled temperature (30°C at the beginning and 25°C at the end of the experiment, with a 1°C decrease every 3 days), heated additionally by IR lamps for the first 7 days, and had always free access to their assigned experimental diet feed and water, starting on day 0.…”

“…Escherichia coli F4ac challenge and sampling On day 7 post-weaning, all the pigs were orally dosed with a 1.5 ml suspension containing 10 8 CFU of ETEC O149:F4ac/ml, prepared as described by Trevisi et al (2015b). A lyophilized live yeast strain of Sc (CNCM I-4407, Actisaf; Phileo-Lesaffre Animal Care, Marcq-en-Baroeul, Nord-Pas-de-Calais-Picardie, France) was mixed in the diet.…”

The relevance of functional amino acids to support the health of growing pigs

“…Experimentally induced ileitis increased the utilization of arterial-blood Thr by the portal-drained viscera, and ileal mucin synthesis in mini pigs (Rémond et al, 2009). However, when the dietary ratio of Thr:Lys was increased from 65% to 70%, ETEC-susceptible weaned pigs orally challenged with ETEC did not exhibit a change in the total mucin content in jejunal mucosal scrapings (Trevisi et al, 2015a). The lack of an effect of supplementary Thr can be explained, in part, by the fact that mucin-13, which is mainly expressed in the jejunum of pigs, is not rich in Thr, in contrast to other mucins that are dominant in other segments of the gastrointestinal tract.…”