|Yi, Ganfeng - NOVUS INTERNATIONAL, INC.|
|Allee, Gary - UNIVERSITY OF MISSOURI|
|Gaines, Aaron - UNIVERISTY OF MISSOURI|
|Kendall, Dustin - UNIVERSITY OF MISSOURI|
|Usry, James - AJINOMOTO HEARTLAND LYSIN|
|Toride, Y - AJINOMOTO CO., INC, TOKYO|
|Izuru, S - AJINOMOTO CO., INC, TOKY0|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 3, 2004
Publication Date: February 20, 2005
Citation: Yi, G.F., Carroll, J.A., Allee, G.L., Gaines, A.M., Kendall, D.C., Usry, J.L., Toride, Y., Izuru, S. 2005. Effect of glutamine and spray-dried plasma on growth performance, small intestinal morphology, and immune responses in Escherichia coli K88+ challenged weaned pigs. Journal of Animal Science. 83:634-643. Interpretive Summary: Glutamine has important and unique metabolic functions, and is considered to be a conditionally essential amino acid in some species under inflammatory conditions such as infection and injury or in catabolic disease states. Glutamine, the main energetic substrate for rapidly proliferating cells including intestinal enterocytes and activated lymphocytes, has effects in enhancing lymphocyte response to mitogen stimulation and alleviating bacteremia and endotoxemia. In various stress states associated with bacterial translocation, the provision of glutamine-enriched enteral or parenteral diets reduces the incidence of translocation of bacteria by decreasing the adherence of bacteria to intestinal enterocytes and normalizing the IgA levels. The positive effects of spray-dried plasma on improving the growth performance of weaning pigs have been well documented, especially during the first two weeks after weaning. Dietary spray-dried plasma supplementation up to 6% increases gain and feed intake in the first two weeks after weaning in a dose-dependent fashion. Recently, there have been several studies conducted with weaned pigs to investigate the effects of feeding spray-dried plasma on the modulation of immune function and protection against exogenous pathogens or endotoxin challenges. It has been reported that feeding spray-dried plasma reduced the excretion of pathogenic Escherichia coli in the feces and provided protection against clinical symptoms associated with orally administered F18+ Escherichia coli challenged weaned pigs. Spray-dried plasma may have effects on improving the intestinal morphology and maintaining gut integrity by preventing intestinal pathogen invasion and local destruction of intestinal mucosal barrier. Therefore, the objectives of this study were to test the essentiality of glutamine under enterotoxigenic Escherichia coli (ETEC) challenged situations; to investigate the effects of feeding glutamine or spray-dried plasma supplemented diets on growth performance and small intestinal morphology of orally K88+ ETEC challenged weaned pigs; to study the impact of glutamine or spray-dried plasma on the stress and somatotrophic axes modulation and immune responses after ETEC infection; and to explore nutritional modulation in alleviating the detrimental effects of pathogenic exposure and stresses associated with the practice of early-weaning. Our results indicated that feeding spray-dried plasma or glutamine has beneficial effects in alleviating growth depression in Escherichia coli K88+ challenged pigs mainly via maintaining intestinal morphology and function, and (or) possibly via modulating the somatotrophic axis. Both glutamine and spray-dried plasma were effective in alleviating growth depression caused by an Escherichia coli K88+ challenge. Feeding either spray-dried plasma or glutamine mitigated villus atrophy and intestinal morphology disruption after E. coli challenge, indicating the beneficial effects of spray-dried plasma and glutamine in preventing pathogenic invasion and colonization, and maintaining normal intestinal integrity and function. Feeding spray-dried plasma or glutamine may have different modulatory mechanisms on the growth hormone/insulin-like growth factor-1 uncoupling under an Escherichia coli challenged situation. This information will be of interest to scientists in academia, industry, and government agencies who conduct research in the area of nutritional mediation of immune function and the utilization of nutritional supplements to enhance growth performance following a pathogenic challenge.
Technical Abstract: Forty weaned barrows (5.32 plus or minus 0.3 kg) at 17 plus or minus 2 days of age were used to investigate the effects of feeding glutamine and spray-dried plasma diets on E. coli K88+ challenged pigs. Pigs were allotted in a randomized complete block design to four treatment groups including POS, NEG, SDP, and GLN, in which the POS and NEG groups were fed the same corn-soy-whey-fishmeal diet, and the SDP and GLN groups were fed 7% spray-dried plasma and 2% glutamine supplemented diets, respectively. On day 11 after weaning, all pigs were non-surgically fitted with an indwelling jugular catheter. On day 12 postweaning, pigs in the NEG, SDP, and GLN groups were orally challenged with E. coli K88+, whereas pigs in the POS group were treated with skim milk. Rectal temperatures and fecal diarrheic scores were recorded and blood samples collected at 0 h baseline, 6, 12, 24, 36, and 48 h post-challenge for serum hormone and cytokine measurement. At 48 h post-challenge, all pigs were sacrificed for small intestinal morphology evaluation. There was no beneficial effect of feeding spray-dried plasma or glutamine on growth performance during the 11 d pre-challenge period. At 48 h post-challenge, compared to the non-challenged POS group, pigs in the NEG group had decreased ADG and G:F (P < 0.08). However, feeding either spray-dried plasma or glutamine alleviated growth depression and feed efficiency reduction associated with E. coli challenge. At 12 h post-challenge, pigs in the NEG group had the highest incidence of diarrhea among treatments (P < 0.09). Additionally, pigs in the NEG group had a higher incidence of diarrhea relative to the POS group at 36 h (P < 0.05) and 48 h (P < 0.07) post-challenge. There was no treatment by time interaction for rectal temperature (P > 0.81), ACTH (P > 0.74), cortisol (P > 0.43), or IL-6 (P > 0.10) within 48 h of E. coli challenge. In proximal, mid-jejunum and ileum, compared with the POS group, pigs in the NEG group had greater villous atrophy and intestinal morphology disruption (P < 0.08), whereas feeding either spray-dried plasma or glutamine mitigated villous atrophy and intestinal morphology impairment after E. coli challenge. At 6 h post-challenge, compared to the baseline, all pigs had increased GH (P < 0.001) and decreased IGF-1 (P < 0.001). At 12 h post-challenge, pigs in the POS group had higher serum IGF-1 compared to the E. coli challenged pigs in the NEG, SDP, and GLN groups (P < 0.08). At 36 h post-challenge, pigs in the SDP group had the greatest serum concentration of GH among treatments (P < 0.05). These results indicate that feeding spray-dried plasma or glutamine has beneficial effects in alleviating growth depression in E. coli K88+ challenged pigs mainly via maintaining intestinal morphology and function, and (or) possibly via modulating the somatotrophic axis.