An experiment was conducted to determine whether baby pigs develop hypersensitivity to dietary soybean proteins. Thirty-two pigs were orally infused with either dried skim milk (5 g/d; control) or soybean meal (48% CP; 5 g/d) from d 7 to 14 after birth. Sows were fed a corn-corn gluten meal-based diet supplemented with lysine and tryptophan to avoid exposure of pigs to soybean proteins. Pigs were weaned at 21 d of age and fed diets containing either soybean meal or milk proteins until d 56. One half of the pigs were killed at 28 d of age and the rest at 56 d of age. Segments of small intestine were collected, and intraepithelial lymphocytes were isolated. At 28 d of age, pigs fed diets containing soybean meal had lower (P less than .05) villus height (221 vs 298 microns) and rate of gain (86 vs 204 g/d) than control pigs did. Pigs fed a diet containing soybean meal had higher (P less than .05) immunoglobulin G (IgG) titers to soybean protein than did pigs fed a milk protein-based diet. Blood and intestinal lymphocytes collected on d 28 and 56 did not exhibit any proliferative response when cultured with purified soy proteins (2.5 or 5 microns/ml). Phytohemagglutinin- and pokeweed mitogen-induced lymphocyte proliferations were higher (P less than .05) at d 56 than at d 28, but there were no differences attributable to protein source. There were no differences (P greater than .05) in skin-fold thickness measurements following intradermal injection with soy or milk proteins. Decreased villus height and increased serum IgG titers to soybean proteins coinciding with inferior performance of early weaned pigs fed diets containing soybean meal indicate that conventionally processed, commercial soybean meal may retain some antigens that can cause transient hypersensitivity in piglets.

Multiparous sows (n = 307) were used to evaluate the effects of added dietary L-carnitine, 100 mg/d during gestation and 50 ppm during lactation, on sow and litter performance. Treatments were arranged as a 2 (gestation or lactation) x2 (with or without L-carnitine) factorial. Control sows were fed 1.81 kg/d of a gestation diet containing .65% total lysine. Treated sows were fed 1.59 kg/d of the control diet with a .23 kg/d topdressing of the control diet that provided 100 mg/d of added L-carnitine. Lactation diets were formulated to contain 1.0% total lysine with or without 50 ppm of added L-carnitine. Sows fed 100 mg/d of added L-carnitine had increased IGF-I concentration on d 60 (71.3 vs. 38.0 ng/mL, P<.01) and 90 of gestation (33.0 vs. 25.0 ng/mL, P = .04). Sows fed added L-carnitine had increased BW gain (55.3 vs 46.3 kg; P<.01) and last rib fat depth gain (2.6 vs. 1.6 mm; P = .04) during gestation. Feeding 100 mg/d of added L-carnitine in gestation increased both total litter (15.5 vs. 14.6 kg; P = .04) and pig (1.53 vs 1.49 kg; P<.01) birth weight. No differences were observed in pig birth weight variation. Added L-carnitine fed during gestation increased litter weaning weight (45.0 vs. 41.3 kg, P = .02); however, no effect of feeding L-carnitine during lactation was observed. No differences were observed in subsequent days to estrus or farrowing rate. Compared to the control diet, feeding added L-carnitine in either gestation, lactation, or both, increased (P<.05) the subsequent number of pigs born alive, but not total born. In conclusion, feeding L-carnitine throughout gestation increased sow body weight and last rib fat depth gain and increased litter weights at birth and weaning.

Two trials were conducted to determine the suitability of soybean products for baby pigs. Weanling pigs (n = 40 and 48 in Trials 1 and 2, respectively) were infused orally (6 g/d) with dried skim milk, soybean meal (SBM, 48% CP); soy protein concentrate, moist extruded soy protein concentrate, or soy protein isolate from d 7 to 12 of age. Pigs were then fed a diet containing the same protein source for 1 (Trial 1) or 2 (Trial 2) wk after weaning (d 21 of age). To avoid exposure of pigs to soybean proteins, the dams of pigs were fed a corn-corn gluten meal-based diet supplemented with lysine and tryptophan from d 109 of gestation. All pigs in Trial 1 were killed at 28 d of age, and samples of ileal digesta and small intestine were obtained. In Trial 2, the soy protein isolate was not included, and all pigs were fed a diet containing 4% soybean oil and 1.25% lysine for the last 3 wk of the trial. Growth performance, skin-fold thickness, after intradermal injection of extracts of the corresponding proteins, and anti-soy immunoglobulin G (IgG) titers were measured. Results indicated that pigs fed diets containing SBM had lower (P less than .05) villus height and xylose absorption but higher (P less than .05) serum anti-soy IgG titers and increased skin-fold thickness compared with the mean of pigs given milk and all other soy treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Three experiments, using 344 pigs, were conducted to evaluate the influence of beta-glucan on growth performance, neutrophil and macrophage function, haptoglobin production, and resistance to Streptococcus suis challenge in weanling pigs. In Exp. 1, 144 pigs were used to evaluate the influence of .1% dietary beta-glucan in a soybean meal- or milk protein-based diet on growth performance and neutrophil function. Pigs fed beta-glucan from d 7 to 14 after weaning had lower ADFI (P < .01) and, although not significant, ADG was lower for pigs fed beta-glucan than for pigs fed control diets. However, no differences were observed in growth performance or neutrophil function for pigs fed control or diets containing beta-glucan from d 7 to 35 after weaning. Experiment 2 was a 28-d growth assay in which pigs were fed a diet with or without .1% beta-glucan, containing 7.5% spray-dried plasma protein and 25% dried whey from d 0 to 14 after weaning. Pigs then were fed corn-soybean mealbased diets containing 2.5% spray-dried blood meal and 10% dried whey. No differences in growth performance were observed. Experiment 3 was a 35-d assay to evaluate growth performance, neutrophil and macrophage function, and plasma haptoglobin concentration. Pigs were challenged on d 28 postweaning with intravenous S. suis. In Exp. 3, pigs were fed diets without or with .025 or .05% beta-glucan. Dietary beta-glucan did not influence neutrophil or macrophage function. However, pigs fed diets containing .025% beta-glucan had increased (P < .05) ADG and ADFI and were heavier (P < .05) on d 28 after weaning than pigs fed the control diet. No differences in feed efficiency (G/F) were detected between treatments. Pigs fed beta-glucan had decreased (P < .10) plasma haptoglobin on d 14, 21, and 28 after weaning. However, Fisher's Exact test revealed that more (P < .04) pigs fed a diet containing .025% beta-glucan died by d 12 after challenge with S. suis. In conclusion, these data suggest the existence of a complex interaction involving growth performance and resistance to S. suis in pigs fed .025% beta-glucan.

Three growth assays were conducted to determine the efficacy of replacing dried skim milk and(or) dried whey in diets of starting pigs with commercially available spray-dried porcine plasma, spray-dried porcine blood, spray-dried bovine plasma, or spray-dried extracted meat protein. In Exp. 1, 236, 24-d-old crossbred pigs were fed diets containing either skim milk and whey or porcine plasma from 0 to 14 d postweaning and whey or porcine plasma from 14 to 28 d. Although pigs fed diets containing porcine plasma had greater ADFI and ADG than those fed milk products from 0 to 7 d, no differences were observed from d 0 to 14 or from 14 to 28 d postweaning. In Exp. 2, 204, 21-d-old pigs were fed corn-soybean meal-based diets using the following supplemental protein source combinations: skim milk and whey; skim milk, whey, and casein; porcine plasma, whey, and lactose/starch (10%); porcine plasma and lactose/starch (24.4%); or whey. A common diet (1.25% lysine, 10% whey) was fed from 14 to 35 d postweaning. Pigs fed diets containing porcine plasma consumed more feed and had greater ADG than others (P < .05) from 0 to 14 d and from 0 to 35 d. Both ADG and ADFI were highest when the diet contained 10.3% porcine plasma, 20% whey, and 10% added lactose. Experiment 3 used 150, 21-d-old pigs to compare the inclusion of skim milk, porcine plasma, porcine blood, bovine plasma, or meat extract in diets fed from 0 to 14 d postweaning. A common diet (the same as in Exp. 2) was fed from 14 to 35 d. Pigs fed porcine plasma had greater ADFI (P < .05) from 0 to 14 d than pigs fed other treatments. Also, pigs fed porcine plasma had greater ADG (P < .05) from 0 to 14 d than pigs fed all other diets except porcine blood. Pigs fed porcine blood had the largest ADFI (P < .05) from 14 to 35 d compared with pigs fed other diets. These experiments indicate that porcine plasma is a protein supplement superior to skim milk in diets of starting pigs and that porcine blood has a positive influence on subsequent growth performance.