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Weaning is an inevitable early life stressor in commercial production that can cause an immediate reduction in voluntary feed intake and growth during a critical period of gastrointestinal development. Further, the reduction in voluntary feed intake is strongly correlated with the risk of disease during that period. Therefore, our objective was to test the effect of different dietary interventions on early nursery pig feed intake, performance, fecal consistency, and histological parameters. Over 2 repetitions, a total of 90 newly weaned gilts (19-21 d of age, BW 5.62 ± 1.1 kg) were selected, individually penned and randomly assigned to 1 of 5 dietary treatments (n = 18 pigs/treatment) that included: 1) Control diet (CON), 2) CON + 5% sugar beet pulp (BP), 3) CON + 10% high fructose corn syrup (HFCS), 4) CON + 5% soyhulls (SH), or 5) CON + 3,000 ppm Zn and 200 ppm Cu (d 0-7), and 2,000 ppm Zn and 200 ppm Cu (d 8-14; ZC). Each repetition was conducted over a 14-d period consisting of 2 phases (Phase 1: d 0-7, phase 2: d 8-14). Pigs were all sourced from a natural endemic enteric pathogen positive nursery flow and confirmed positive for rotavirus, coccidia and F18 E. coli. Fecal consistency was scored and feed disappearance was recorded daily. On d 0, 7 and 14, pig BW were collected. Weekly feed disappearance and BW were used to calculate ADG, ADFI and feed efficiency (G:F) within phase and overall. On d 14, all pigs were euthanized, and fixed sections of ileum and colon were collected to assess histopathology including incidence of villus atrophy and colitis. Pig was the experimental unit, and performance and histology data were analyzed by dietary treatment. Daily measures of feed intake were analyzed by repeated measures with the fixed effects of diet, day, and their interaction. Starting BW did not differ across dietary treatments (P = 0.845). Over the 14-d test period, HFCS and ZC treatments tended to increase ADG (0.20 and 0.15 kg/d, respectively) compared with CON, BP and SH (0.09, 0.12, and 0.13 kg/d, respectively; P = 0.076). Further, the addition of a sweetener (HFCS) did not improve daily feed intake, while SH reduced daily feed intakes by 32% compared with all other treatments (P < 0.001). Although all pigs had some degree of diarrhea, fecal consistency did not differ between dietary treatments (P = 0.618). Histopathology scoring for intestinal atrophy (ileum) and colitis (colon) were not different (P = 0.645 and 0.440, respectively). In conclusion, the addition of BP, HFCS, SH and ZC had an effect on growth and feed intake but there was no benefit in atrophy, colitis, and fecal scores when encountering a natural enteric pathogen burden. [ABSTRACT FROM AUTHOR]

Weaning induces major structural and function changes to the small intestine of pigs and they transition from milk to solid feedstuffs. Thus, the objective of this study was to determine how intestinal morphology and function markers relate to feed intake and growth rates of nursery pig. Forty-eight weaned pigs (5.63 ± 0.50 kg) were randomly selected, individually penned and fed a common diet. Pig bodyweights and feed intake were determined at d 2, 7, and 21. At each time point, 16 pigs were randomly selected and euthanized. Sections of ileum were assessed for morphology [villus height (VH), crypt depth (CD) and VH:CD] and ex vivo transepithelial resistance (TER), macromolecule permeability (FD4), and active transport of glucose and glutamine via modified Ussing chambers. Within each period (d 0-2, 0-7, and 0-21), Pearson correlations were performed between ADG, ADFI, VH, VH:CD, TER, FD4 and active transport of glucose and glutamine. At d 2 post-weaning, no correlations (P > 0.05) were observed between performance and intestinal variables. By d 7, moderate positive correlations between VH and ADFI (r = 0.69, P = 0.005), VH and ADG (r = 0.68, P = 0.006) were reported. At 21 d post-weaning, moderate positive correlations were still observed for VH and ADFI (r = 0.55, P = 0.026) and between VH and ADG (r = 0.51, P = 0.042). Interestingly, ADFI and ADG tended to be negatively correlated with active glucose transport (r = -0.45, P = 0.083 and r = -0.47, P = 0.064, respectively) and active glutamine transport (r = -0.45, P = 0.083 and r = -0.46, P = 0.073, respectively). Markers of ileal integrity (TER and FD4) were not correlated with ADG or ADFI at any time point. Altogether, these data highlight the importance of intestinal morphology on early nursery pig performance. [ABSTRACT FROM AUTHOR]

Weaned pigs are typically fed complex, highly digestible diets to maximize feed intake and weight gain as they transition into the nursery. Further, pharmacological concentrations of zinc (Zn) and copper (Cu) are commonly fed to mitigate weaning-related diarrhea and performance reductions. A 2 x 2 factorial design was utilized to determine the effect of diet complexity with or without Zn and Cu. Four-hundred and thirty-two weaned pigs were randomly allotted to 48 pens (n = 9 pigs/pens). Pens were assigned to one of four diets: 1) A high soybean meal diet (Simple), 2) Simple + ZnCu, 3) Low soybean meal diet with spray-dried plasma, casein, and oats (Complex), and 4) Complex + ZnCu. Diets were fed in two 14 d phases. For ZnCu there were 3,000 and 2,000 ppm Zn in phase 1 and 2, and 200 ppm Cu in both phases. Bodyweight and feed intake were determined in phase 1 (d 0-14) and phase 2 (d 15-28). Pen was the experimental unit and all data were analyzed by diet complexity, pharmacological minerals and their interaction. No complexity by ZnCu interaction or diet complexity effects were observed in the 28 d study. However, ZnCu increased ADG (0.23 vs. 0.16 kg/day, P < 0.0001), ADFI (0.28 vs. 0.24 kg/d, P < 0.0001), and GF (0.80 vs. 0.69, P < 0.0001) in phase 1. In phase 2, ZnCu increased ADG by 9% (P = 0.008) and ADFI by 16% (P = 0.0001) compared to nonsupplemented counterparts. Overall (0-28 d), ZnCu pigs had heavier end bodyweight (15.9 vs. 14.5 kg, P = 0.009), and greater ADFI (0.47 vs. 0.41 kg/d, P < 0.0001). In conclusion, diet complexity (high levels of soybean meal versus specialized protein alternatives) did not alter nursery performance. Irrespective of diet complexity, pharmacological Zn and Cu improved performance parameters. [ABSTRACT FROM AUTHOR]

The physiological mechanisms by which in-feed antibiotics improve pig growth performance are largely unknown. One proposed mode of action is improvements in intestinal integrity and function. Therefore, the objective of this study was to test the hypothesis that in-feed therapeutic and sub-therapeutic antibiotics would improve intestinal integrity and function in nursery pigs. Twenty-four weaned pigs (6.1±1.1 kg BW) were randomly allotted to individual pens and assigned one of three dietary treatments as follows (n = 8 pigs/trt): 1) control, no antibiotics (CON), 2) CON + subtherapeutic chlortetracycline [40 ppm in feed (sCTC)], and 3) CON + chlortetracycline-tiamulin [400 ppm + 35 ppm, respectively (CTCDen)]. The study consisted of two consecutive 14 d phases. Chlortetracyclinetiamulin was only fed in phase 1, sCTC was fed in both phases. Phase 1 and 2 ADG, ADFI, and G:F were determined. After 28 d, ileal and colonic ex vivo intestinal integrity was assessed via transepithelial resistance (TER) and macromolecule flux (FD4) in modified Ussing chambers. All data were analyzed for the fixed effects of treatment and start BW as a covariate. In phase 1, compared with CON and sCTC, CTCDen tended to have greater ADG (0.28, 0.31, and 0.33 kg/d, respectively, P = 0.10) and ADFI (0.28, 0.30, and 0.35 kg/d, respectively, P = 0.09). No differences in phase 1 G:F were observed (P = 0.11). Phase 2 ADG, ADFI, and G:F did not differ (P > 0.10). Further, ileal TER and FD4 did not differ (P > 0.10). Colonic TER tended to be increased in sCTC compared with CON and CTCDen (78, 56, and 59 Ω/cm2, respectively, P = 0.07). Compared with CON, colonic FD4 flux was decreased in sCTC and CTCDen by 35-40% (P = 0.03). Altogether, these data indicate that in-feed antibiotics improve colon integrity early in production which may contribute to improved growth performance. [ABSTRACT FROM AUTHOR]