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A study involving nine research stations from the NCR-42 Swine Nutrition Committee used a total of 1,978 crossbred pigs to evaluate the effects of dietary ZnO concentrations with or without an antibacterial agent on postweaning pig performance. In Exp. 1, seven stations (IA, MI, MN, MO, NE, ND, and OH) evaluated the efficacy of ZnO when fed to nursery pigs at 0, 500, 1,000, 2,000, or 3,000 mg Zn/kg for a 28-d postweaning period. A randomized complete block experiment was conducted in 24 replicates using a total of 1,060 pigs. Pigs were bled at the 28-d period and plasma was analyzed for Zn and Cu. Because two stations weaned pigs at [is less than] 15 d (six replicates) and five stations at [is greater than] 20 d (18 replicates) of age, the two sets of data were analyzed separately. The early-weaned pig group had greater (P [is less than] 0.05) gains, feed intakes, and gain:feed ratios for the 28-d postweaning period as dietary ZnO concentration increased. Later-weaned pigs also had increased (P [is less than] 0.01) gains and feed intakes as the dietary ZnO concentration increased. Responses for both weanling pig groups seemed to reach a plateau at 2,000 mg Zn/kg. Plasma Zn concentrations quadratically increased (P [is less than] 0.01) and plasma Cu concentrations quadratically decreased (P [is less than] 0.01) when ZnO concentrations were [is greater than] 1,000 mg Zn/kg. Experiment 2 was conducted at seven stations (KY, MI, MO, NE, ND, OH, and OK) and evaluated the efficacy of an antibacterial agent (carbadox) in combination with added ZnO. The experiment was a 2 x 3 factorial arrangement in a randomized complete block design conducted in a total of 20 replicates. Carbadox was added at 0 or 55 mg/kg diet, and ZnO was added at 0, 1,500, or 3,000 mg Zn/ kg. A total of 918 pigs were weaned at an average 19.7 d of age. For the 28-d postweaning period, gains (P [is less than] 0.01), feed intakes (P [is less than] 0.05), and gain:feed ratios (P [is less than] 0.05) increased when dietary ZnO concentrations increased and when carbadox was added. These responses occurred in an additive manner. The results of these studies suggest that supplemental ZnO at 1,500 to 2,000 mg Zn/kg Zn improved postweaning pig performance, and its combination with an antibacterial agent resulted in additional performance improvements. Key Words: Copper Sulfate, Pigs, Weaning, Zinc, Zinc Oxide

A cooperative study, using 231 primiand multiparous crossbred sows from six experiment stations (IN, KS, MI, MN, ND, and OH), was conducted to determine the effects of elevating dietary valine concentration in corn-soybean meal diets on lactational performance of sows nursing large litters. Crossbred sows were fed diets containing a minimum of .60% lysine during gestation. Sows were allotted at farrowing to four dietary valine concentrations, .80, .95, 1.10, and 1.25%. Crystalline L-valine replaced cornstarch to maintain a constant ratio of corn:soybean meal across diets. Dietary lysine, provided by corn, soybean meal, and. 15% crystalline L-lysine [multiplied by] HCl, was .90% in all diets. Sows were allowed ad libitum access to feed. Sows were weighed within 24 h after farrowing, and all litters were adjusted to [is greater than or equal to] 10 pigs/litter by d 2 following farrowing. Average sow parity, number of pigs on d 2, and lactation length for the four treatments were, respectively, 2.3, 2.3, 2.3, 2.5; 10.9, 10.8, 10.8, 10.7; and 25.1, 24.5, 25.2, 25.0 d. The ADFI during lactation was 5.87, 5.77, 5.87, and 5.74 kg (P [is greater than] .50); hence, valine intakes were 41, 48, 55, and 61 g/d (linear, P [is less than] .01). Lysine intake ranged from 51.5 to 52.7 g/d (P [is greater than] .50). Sow weight after farrowing averaged 198 kg (P [is greater than] .60). Overall pig survival to weaning was high ([is greater than] 92%), and the number of pigs weaned (10.1, 10.3, 10.3, 10.3) did not differ (P [is greater than] .30) among treatments. Litter weaning weights (73.6, 73.6, 74.5, 72.6 kg), litter weight gains (55.1, 55.1, 56.0, 54.1 kg), sow weight change during lactation (-4.9, -5.4, -4.8, -6.3 kg), and return-to-estrus interval (7.5, 6.4, 6.9, 8.2 d) were not affected (P [is greater than] .30) by dietary valine. There were no station x treatment interactions (P [is greater than] .50). These results indicate no benefit of elevated dietary valine for lactating sows nursing [is greater than or equal to] 10 pigs and consuming a corn-soybean meal diet containing .90% lysine and .80% valine. Key Words: Lactation, Lysine, Sows, Valine

Feeding high-fiber diets decreases cost, but also caloric and nutritional efficiency by modifying intestinal morphology and function. We analyzed the changes in intestinal cell composition, nutrient transporters and receptors, and cell differentiation induced by fibers from different sources. Forty-six finishing pigs (BW 84 ± 7 kg) were fed 1 of 4 diets: corn-soybean (Control; n = 12), 23% wheat straw (WS; n = 11), 55% corn distillers dried grains with solubles (DDGS; n = 11), and 30% soybean hulls (SBH; n = 12). Pigs were fed 2 meals daily to an amount equivalent to 2.5% of initial BW for 14 d in metabolism cages. Ilea were collected for histological and gene expression analysis after euthanasia. Data were analyzed using the Kruskal-Wallis test followed by Dunn's multiple comparisons and differences considered significant when P < 0.05. The enterocyte marker was increased (P < 0.03) by feeding SBH compared with Control and WS diets. Goblet cells presence was greater (P < 0.01) in pigs fed WS and DDGS compared with Control, and in pigs fed WS compared with SBH (P = 0.02). Mucin 2 expression was greater (P < 0.05) in pigs fed DDGS and SBH compared with Control diet. No changes were observed for endocrine and Paneth cells markers, villus and crypt length, or proliferation index. Compared with the Control, gene expression of receptors for oligopeptides, calcium, glucose, fructose, free fatty acid receptor 1, and G protein-coupled receptors 119 and 84 was increased (P < 0.05) by feeding WS and DDGS diets. Feeding SBH diet repressed (P < 0.005) the umami receptor compared with WS and DDGS diets, while DDGS repressed (P = 0.02) its expression compared with Control. Pigs fed DDGS had reduced (P < 0.001) fatty acid receptor 2, and those fed SBH showed increased (P < 0.05) fatty acid translocase expression compared with WS and DDGS pigs. Feeding WS and DDGS diets induced (P < 0.01) the expression of stem cell marker respondin receptor (LGR5), while olfactomedin 4 was reduced (P < 0.02) by feeding DDGS compared with Control. The expression of delta-like Notch ligand 4 was induced (P < 0.05) by all fibers compared with Control. Transcription factors atonal factor 1 and Wnt family 3A were suppressed (P < 0.001) by WS and DDGS compared with Control. In conclusion, feeding diets containing WS and DDGS modulated intestinal differentiation by promoting goblet cells and altered expression of nutrient receptors and transporters in growing pigs, while feeding SBH had less effect. [ABSTRACT FROM AUTHOR]