Nursery Pigs Research Articles

245 Evaluation of Cellulose in Diets with and Without Added Zno on Nursery Pig Performance

Abstract A total of 1,296 pigs (PIC L337×1050; initially 4.8 kg) were used in a 42-d study to evaluate cellulose in diets with and without pharmacological levels of Zn on nursery pig performance. Our hypothesis was that added fiber (cellulose) may provide more benefit in diets without ZnO. Pens were assigned to 1 of 4 dietary treatments in a RCBD by BW with 27 pigs/pen and 12 pens/treatment. Dietary treatments were arranged in a 2×2 factorial with main effects of cellulose (0 vs 1%; J. Rettenmaier USA, Schoolcraft, MI) and Zn (200 vs. 3,000 mg/kg in phase 1 and 110 vs. 2,000 mg/kg in phase 2). Treatment diets were formulated in two phases fed from d 0 to 7 and 7 to 21 with a common diet fed from d 21 to 42 post-weaning. Pig weights and feed disappearance were collected weekly to determine ADG, ADFI, and G:F. On d 16 or 17, fecal samples were collected from 3 pigs/pen to determine fecal DM, and all pens were visually evaluated for fecal consistency. There were no Zn×cellulose interactions. For the experimental and overall period, pigs fed diets containing added Zn had increased (P < 0.001) ADG, ADFI, G:F and BW while those that were fed cellulose had decreased (P < 0.05) ADG. For fecal dry matter, there was no evidence for difference (P >0.10) between any of the treatments but those fed added ZnO had visually firmer feces as evidenced by lower (P < 0.001) fecal scores. When fed a common diet from d 21 to 42, pigs previously fed added ZnO had increased (P < 0.001) ADG (502 vs. 523 g/d) and ADFI (697 vs. 734 g/d). In conclusion, there were no interactive effects between added cellulose and Zn; however, cellulose reduced ADG while the inclusion of pharmacological levels of Zn improved all growth criteria.

29 Live Yeast and Yeast Extracts with and Without Pharmacological Levels of Zinc on Nursery Pig Growth Performance and Fecal Escherichia coli Antimicrobial Resistance

Abstract A total of 360 barrows (DNA 200×400; initially 5.6 kg) were used to evaluate yeast-based probiotics (Phileo by Lesaffre, Milwaukee, WI) in diets with or without pharmacological levels of Zn on growth and fecal Escherichia coli antimicrobial resistance (AMR). There were 5 pigs/pen and 18 pens/treatment. Dietary treatments were arranged in a 2×2 factorial with main effects of yeast pre- and probiotics (0 vs. 0.10% Actisaf Sc 47 HR+, 0.05% SafMannan, and 0.05% Nucleosaf in phase 1 then concentrations were lowered by 50% in phase 2) and pharmacological levels of Zn (110 vs. 3,000 mg/kg in phase 1 and 2,000 mg/kg in phase 2 provided by zinc oxide). Treatments were fed in two phases from d 0 to 7 and 7 to 21 with a common diet fed from d 21 to 42 post-weaning. There were no probiotics×Zn interactions. From d 0 to 21, pigs fed pharmacological Zn had increased (P < 0.001) ADG and ADFI; however, there were no effects of added pre- and probiotics. Fecal samples were collected on d 4, 21, and 42 from the same three pigs/pen for AMR profiles and fecal dry matter (DM). On d 4, pigs fed pharmacological Zn had greater fecal DM (P = 0.043); however, no differences were observed on d 21 or 42. E. coli was isolated from fecal samples and species confirmation was accomplished by PCR detection of uidA and clpB genes. Microbroth dilution method using SensititreTM CMV3AGNF panel was used to determine antimicrobial susceptibilities of E. coli isolates to 14 different antimicrobials. There was no evidence for differences in AMR of fecal E. coli isolates to antibiotics by added pre- and probiotics or Zn. Results suggest that pharmacological levels of Zn stimulate intake and growth and improve fecal consistency in the nursery with no statistical response from added pre- and probiotics.

260 Growth Performance and Gut Integrity of Nursery Pigs Fed Diet with butyric Acid and Enzymatically Hydrolyzed Yeast Product

Abstract The objective of this study was to evaluate the effects of butyric acid (BA) and enzymatically hydrolyzed yeast product (EYP) on growth performance and gut health of nursery pigs. A total of 96 weaned pigs (initial body weight = 6.60 kg) were housed in 24 pens (4 pigs/pen) and fed 3 diets in a randomized complete block design. The diets were corn-soybean meal-based without or with 0.05% BA or 0.1% EYP. The diets were fed in 2 phases; Phase 1: d 0 to 7 and Phase 2: d 7 to 20. Growth performance and fecal score were determined by phase. One pig from in each pen was selected for measuring organ weights, gut permeability, and electrophysiological parameters of jejunum mounted in Ussing chambers. The selected pigs were sacrificed at a rate of 6 pigs (balanced for diets) per day from d 10 to 17. Dietary BA increased (P < 0.05) gain to feed ratio for d 7 to 20 by 5.8% and for entire study period by 15.8%. Fecal scores were unaffected by dietary BA or EYP. Dietary EYP increased (P < 0.05) weight of cecum as a proportion of live body weight by 36.4%. Dietary BA decreased (P < 0.05) the flow of fluorescein isothiocyanate-dextran from mucosal to serosal side of jejunum by 31.7%, implying that dietary BA reduced jejunal permeability. Jejunal short circuit current was decreased (P < 0.05) by dietary BA or EYP. However, jejunal trans-epithelial electrical resistance was unaffected by dietary BA or EYP. In conclusion, dietary BA improved feed efficiency and reduced jejunal permeability to fluorescein isothiocyanate-dextran, implying that it can improve the gut health of weaned pigs through reduced jejunal permeability to toxins. Dietary EYP increased caecum weight, implying that it can improve hindgut fermentation in weaned pigs.

247 The Effect of Feeding Low Complexity Diets Contaminated with Deoxynivalenol and Supplemented with Nutramixtm or Fish Oil on Nursery Pig Growth Performance

Abstract Three hundred twenty newly weaned pigs (6.7±0.3 kg BW) were used to determine the effect of low complexity diets contaminated with deoxynivalenol (DON) and supplemented with NutraMixTM or fish oil on nursery pig growth performance. Pigs were randomly divided into 40 pens and assigned to 1 of 5 dietary treatments (n = 8): [1] high-complexity diet containing animal proteins (HC) or one of four low complexity diets with protein supplied only by corn and soybean meal with [2] no DON contamination (LC), or [3] DON contamination of 3 ppm without supplements (DON-), [4] with NutraMixTM supplementation (2 g/kg; DONNM), or [5] with fish oil supplementation (2.5%, as-fed; DONω3). Diets were fed over two phases (7 and 15 days, respectively) and a common phase III diet was fed to all pigs for 20 days. In phase I, ADG, ADFI, and G:F were not different between pigs fed the HC and LC diets, but were lower for pigs fed DONNM and DONω3(P < 0.05). In phase II, pigs fed the DON- and DONω3 diets had lower ADG than LC (375 vs. 410 g/d; P < 0.05) and lower ADFI than HC (452 vs. 519 g/d; P < 0.05), while pigs fed DON- and DONω3 had greater G:F than those fed HC (0.83 vs. 0.78; P < 0.05). The BW at the end of phase II were not different between HC and LC (13.0 kg), but tended to be less for DONω3 (12.6 kg; P = 0.084 and 0.079, respectively). In phase III and over the entire nursery period, there were no treatment effects on ADG, ADFI, G:F, or final BW (26.0±0.7 kg). Feeding low complexity diets contaminated with 3 ppm DON initially reduced growth performance, but pigs were still able to achieve BW not different from HC pigs at the end of the nursery period, regardless of supplementation.

249 Increasing Structural Fiber Improves Growth Performance of Nursery Pigs

Abstract Fiber ingredients in swine diets have various components that affect the intestinal tract distinctively. The objective of this study was to determine the effect of structural fiber sources on growth performance of nursery pigs. A total of 1,760 weanling pigs (initial BW = 6.12 ± 0.3 kg, 16 reps/trt, 22 pigs/pen) were used in a study with 5 dietary treatments: 1) Complex nursery diet with no additional fiber (CON); 2) CON + 2% rice hulls; 3) CON + 4% rice hulls; 4) CON + 6% wheat middlings; 5) CON + 12% wheat middlings. Fiber ingredients were added at the expense of corn and some processed soybean meal to maintain similar dietary protein levels. Using an in vitro fermentation estimation of fermentation for rice hulls and wheat middlings, diets were constructed to add similar levels of structural (non-fermentable NDF) fiber between low and high additions of rice hulls and wheat middlings. Pens across two barns were randomly allotted independent of one another and within a location block to one of the five treatments on d 0 of a two-phase study (d 0–11 and d 11–20.5 post-weaning). Data were analyzed by general linear model in R. Mortality and removal data were analyzed as a generalized linear mixed model with a binomial distribution. Contrasts tested the effect of additional fiber (CON vs treatments 2–5), effect of medium vs high fiber (treatment 2/4 vs 3/5), effect of source of fiber (treatment 2/3 vs 4/5), and the interaction of level and source of fiber. Overall (Table 1), additional fiber resulted in increased ADFI (P < 0.05) and tended to increase ADG (P < 0.10). Probability of mortality and removal was reduced (P < 0.05) when additional fiber was included. In summary, increasing the level of structural fiber improved performance and livability of nursery pigs.

Evaluation of the microbiome composition in particulate matter inside and outside of pig houses

Particulate matter (PM) produced in pig houses may contain microbes which can spread by airborne transmission, and PM and microbes in PM adversely affect human and animal health. To investigate the microbiome in PM from pig houses, nine PM samples were collected in summer 2020 inside and outside of pig houses located in Jangseong-gun, Jeollanam-do Province, Korea, comprising three PM samples from within a nursery pig house (I-NPH), three samples from within a finishing pig house (I-FPH), and three samples from outside of the pig houses (O-PH). Microbiomes were analyzed using 16S rRNA gene amplicon sequencing. Firmicutes was the most dominant phylum and accounted for 64.8%–97.5% of total sequences in all the samples, followed by Proteobacteria (1.4%–21.8%) and Bacteroidetes (0.3%–13.7%). In total, 31 genera were represented by > 0.3% of all sequences, and only Lactobacillus, Turicibacter, and Aerococcus differed significantly among the three PM sample types. All three genera were more abundant in the I-FPH samples than in the O-PH samples. Alpha diversity indices did not differ significantly among the three PM types, and a principal coordinate analysis suggested that overall microbial communities were similar across PM types. The concentration of PM did not significantly differ among the three PM types, and no significant correlation of PM concentration with the abundance of any potential pathogen was observed. The present study demonstrates that microbial composition in PM inside and outside of pig houses is similar, indicating that most microbe-containing PM inside pig houses leaks to the outside from where it, along with microbe-containing PM on the outside, may re-enter the pig houses. Our results may provide useful insights regarding strategies to mitigate potential risk associated with pig farming PM and pathogens in PM.

Weaning Induced Gut Dysfunction and Nutritional Interventions in Nursery Pigs: A Partial Review.

Simple SummaryThe beneficial and functional roles of the gut microbiota in maintaining host health are becoming clearer. In general, the swine intestinal bacterial population is predominated by two phyla, Firmicutes and Bacteroidetes, followed by Proteobacteria, Actinobacteria, and Spirochaetes, among others. This general profile is relatively stable, although variations exhibit below the phylum level when the gut microbiota experiences dysbiosis. At weaning, dietary and environmental changes often result in gut microbiota dysbiosis, which is frequently associated with post-weaning diarrhea and enteric infections. A healthy gut microbiota possesses specific capacities involving nutrient metabolism, immunomodulation, controlling inflammation, and maintaining intestinal barrier function and structure. Manipulating the gut microbiota through diet is a useful strategy to attenuate weaning stress and restore microbiota homeostasis. Understanding the interaction between feed additives and gut microbiota would facilitate the development of effective feeding strategies to improve the gut health, growth performance, and well-being of nursery pigs. This review summarizes certain feed additives, which are used to modulate gut microbiota with some success.Weaning is one of the most stressful events in the life of a pig. Unsuccessful weaning often leads to intestinal and immune system dysfunctions, resulting in poor growth performance as well as increased morbidity and mortality. The gut microbiota community is a complex ecosystem and is considered an “organ,” producing various metabolites with many beneficial functions. In this review, we briefly introduce weaning-associated gut microbiota dysbiosis. Then, we explain the importance of maintaining a balanced gut microbiota. Finally, we discuss dietary supplements and their abilities to restore intestinal balance and improve the growth performance of weaning pigs.

Correlation of Neutralizing Antibodies (NAbs) between Sows and Piglets and Evaluation of Protectability Associated with Maternally Derived NAbs in Pigs against Circulating Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) under Field Conditions.

Porcine reproductive and respiratory syndrome (PRRS), which is caused by a highly transmissible pathogen called porcine reproductive and respiratory syndrome virus (PRRSV), has caused severe problems, including reproductive disorders in sows and respiratory symptoms in nursery pigs worldwide, since the early 1990s. However, currently available PRRSV vaccines do not supply complete immunity to confront the viral infection. Elicitation of PRRSV-specific neutralizing antibodies (NAbs) during the preinfectious period has been deemed to be a feasible strategy to modulate this virus, especially in farms where nursery pigs are seized with PRRSVs. A total of 180 piglets in a farrow-to-finish farm that had a natural outbreak of PRRS were distributed into three groups based on the different PRRSV NAbs levels in their dams. In the present study, piglets that received superior maternal-transferred NAbs showed delayed and relatively slight viral loads in serum and, on the whole, higher survival rates against wild PRRSV infections. A positive correlation of maternal NAbs between sows and their piglets was identified; moreover, high NAbs titers in piglets can last for at least 4 weeks. These results provide updated information to develop an appropriate immune strategy for breeding and for future PRRSV control under field conditions.

A Moderate Reduction of Dietary Crude Protein Provide Comparable Growth Performance and Improve Metabolism via Changing Intestinal Microbiota in Sushan Nursery Pigs.

Simple SummaryDietary protein is an important source of amino acids for livestock, while excess protein consumption and an imbalance of amino acids in the diet result in increased feed costs and an increased risk of diarrhea, caused by the proliferation of pathogenic bacteria. Therefore, we investigated whether a diet with a moderate reduction of crude protein levels, supplemented with crystalline amino acids, could alleviate these problems. The results showed that a moderate reduction in the dietary protein level can provide similar growth performance and improve metabolism, due to the improvement of intestinal microbiota, compared with high protein feed in Sushan nursery pigs. These findings present new insights into the role of microorganisms in metabolism, and point to a potential nutrition strategy for indigenous pig production.In this paper, we investigated the effects of a diet with a moderate reduction of dietary crude protein (CP) level, supplemented with five crystalline amino acids (Lys, Met, Thr, Try, and Val), on the growth, metabolism, and fecal microbiota of Sushan nursery pigs. Seventy Sushan nursery pigs with an average body weight of 19.56 ± 0.24 kg were randomly allocated to two experimental dietary treatments: 18% CP (high protein; group HP), and 15% CP (low protein; group LP). We found that the differences in the two diets had no significant effect on the growth performance of Sushan nursery pigs. Nursery pigs on the 15% CP diet showed significantly improved protein, amino acid, and energy utilization. Furthermore, the LP diet cloud optimized the gut microflora composition to some extent. The functional structure of bacterial communities implied improved metabolic capabilities in group LP. Additionally, correlation analysis between fecal microbiota and metabolic profiles confirmed that the increase of beneficial bacterial in the feces was beneficial to the health and metabolism of the nursery pigs. In conclusion, a moderate reduction in the dietary protein level can improve growth and metabolism due to the improvement of intestinal microbiota in Sushan nursery pigs. This finding could provide useful reference data for the application of a different nutrition strategy in indigenous pig production.

Effect of Lactylate and Bacillus subtilis on Growth Performance, Peripheral Blood Cell Profile, and Gut Microbiota of Nursery Pigs.

To evaluate the effects of lactylate and Bacillus subtilis on growth performance, complete blood cell count, and microbial changes, 264 weaning pigs were assigned to four treatments (1) control (Con) basal diets that met the nutrient requirement for each phase, (2) 0.2% lactylate (LA), (3) 0.05% Bacillus subtilis strains mixtures (BM), or (4) the combination of LA and BM (LA+BM) added to the control basal diet at their respective inclusion rates in each of the three phases. Dietary lactylate tended to increase weight gain, significantly increased feed intake, and reduced fecal total E. coli and enterotoxigenic E. coli counts during Phase 1. Pigs fed Bacillus subtilis had a greater gain to feed ratio (G:F) during Phases 1 and 2. Pigs fed lactylate had an increased peripheral absolute neutrophil count on D14 but a decreased eosinophil percentage. Pigs fed Bacillus subtilis had an elevated peripheral total white blood cell count at study completion. The addition of lactylate increased microbiota richness, reduced E. coli, and increased Prevotella, Christensenellaceae, and Succinivibrio. Bacillus subtilis supplementation-enriched f_Ruminococcaceae_unclassified and S24-7_ unclassified had positive relationships with feed efficiency. Collectively, these findings suggested that lactylate can be added to diets to balance gut microbiota and improve growth performance during the early postweaning period. The combination of lactylate and Bacillus subtilis strains exerted a synergic effect on the growth performance of nursery pigs.

Study of the relationship between untypable and typable isolates of Streptococcus suis recovered from clinically ill and healthy nursery pigs

Streptococcus suis naturally colonizes the upper respiratory tract of pigs and can lead to severe disease conditions. Although there are several serotypes associated with disease, untypable isolates have also been observed. The objective of this study was to investigate the relatedness of untypable S. suis isolates detected in clinical cases and healthy pigs in Ontario, Canada, and their relation to typing serotypes. One hundred fifty-six isolates obtained from 33 cases and 26 farm-and-pen-matched control pigs were sequenced using Illumina HiSeq sequencing. Protein sequences of the capsular polysaccharide genes (cps) were identified and analyzed using a maximum likelihood tree. Among the 27 untypable isolates, 3 were from systemic sites of cases and 13 and 11 were from upper respiratory sites of cases and controls, respectively. One hundred fifty-six isolates were grouped into 17 distinct groups based on the cps gene tree. Isolates from these 17 distinct individual cps groups were distributed among a minimum of one farm and maximum of eight farms. Untypable isolates were detected in 12 of those groups and each cps group had untypable isolates present amongst multiple farms. Interestingly, the three systemic untypable isolates not only coexisted with other serotypes found in the same location of the same pigs but were also found among different cps groups. These isolates are of interest and warrant further investigation. Overall, a wide diversity of S. suis among untypable isolates was observed in this study.

44. Effect of changing water to diet ratio over time on nursery pigs’ performance fed wet/dry diets

44. Effect of changing water to diet ratio over time on nursery pigs’ performance fed wet/dry diets

Supplementation of protease to low amino acid diets containing superdose level of phytase for wean-to-finish pigs: effects on performance, postweaning intestinal health and carcass characteristics.

This experiment investigated the effects of protease supplementation to low amino acid (AA) diets containing phytase on pig growth performance, postweaning intestinal health and carcass characteristics. A total of 936 weaned pigs (21 d of age, initial BW 5.87 ± 0.31 kg) were used in a 2 × 2 factorial design comparing the main effects of AA supply [standard feeding program: balanced for all nutrients with adjustment of Ca and P due to inclusion of phytase (2,500 FTU/kg in Phase 1 to 4; 500 FTU/kg in Phase 5 to 9) vs. low AA feeding program: 15% lower standardized ileal digestible lysine with relative reduction of all other essential AA] and protease level (0 vs. 0.0125%). Pens were assigned to dietary treatment according to a randomized complete block design with 26 pigs per pen and nine replicates per dietary treatment. Feed and water were provided on an ad libitum basis for all phases throughout the wean-to-finish period. Feed intake and body weight were determined every 2 wk during nursery period and monthly in the grow-finish period. Intestinal health in the first 17 d was assessed based on lactulose:mannitol ratio (L:M), serum IgA, and pen diarrhea assessment. Overall, pigs fed standard wean-to-finish diets had greater (P < 0.05) ADG and G:F than pigs fed low AA diets. Pig growth performance was not different throughout the wean-to-finish period with or without protease supplementation and with no interaction between AA supply and protease supplementation. There were no differences among dietary treatments for carcass characteristics. No difference was observed for urinary L:M and serum IgA; however, the L:M ratio was approximately 32% lower in pigs fed low AA diets + protease compared with pigs fed standard and low AA diets at d 5 and d 17 postweaning. Pigs fed protease supplemented diets had lower incidence of diarrhea (χ2 < 0.05) compared with pigs fed diets without protease. Results of the experiment indicate that dietary protease supplementation benefits intestinal health of nursery pigs.

Effects of different diet alternatives to replace the use of pharmacological levels of zinc on growth performance and fecal dry matter of weanling pigs.

A total of 300 weanling pigs (Line 400 × 200, DNA, Columbus, NE, initially 4.83 kg) were used in a 46-d trial to evaluate the effects of different nutritional strategies to replace pharmacological levels of Zn, provided by zinc oxide (ZnO), in nursery diets on growth performance and fecal dry matter (DM). Six treatments with 10 replicate pens per treatment and 5 pigs per pen were used. Diets consisted of: (1) positive control (ZnO providing 3,000 mg/kg added Zn from d 0 to 7 and 2,000 mg/kg added Zn from d 8 to 25 and 21% crude protein, CP); (2) negative control (NC; no added ZnO); (3) NC plus 1.2% Na diformate; (4) NC with 4% coarse ground wheat bran; (5) NC but formulated to 18% CP; and (6) the combination of NC with 18% CP, 1.2% Na diformate, and 4% coarse ground wheat bran. The diets formulated to 18% CP contained 1.2% standardized ileal digestible (SID) Lys from d 0 to 25, whereas the 21% CP diets contained 1.4% SID Lys from d 0 to 7 and 1.35% SID Lys from d 7 to 25. From d 25 to 46, all pigs were fed a common diet. From d 0 to 7, no differences in any variables were observed between treatments. From d 7 to 25, pigs fed the diet with added ZnO had greater (P < 0.01) average daily gain (ADG) and average daily feed intake (ADFI) than all other treatments. Pigs fed the diet formulated to 18% CP had decreased (P < 0.01) ADG when compared with pigs fed the other diets. From d 25 to 46, no previous treatment effects on ADG or gain to feed ratio (G:F) were observed. Overall (d 0 to 46), pigs fed the diet with added ZnO from d 0 to 25 had greater (P < 0.01) ADG, ADFI, and final body weight than pigs fed added Na Diformate, or 4% coarse ground wheat bran, or with the 18% CP diet, or with pigs fed the combination of the additives intermediate. There was no evidence for differences in overall G:F. Pigs fed the NC diet had the lowest fecal DM and highest fecal scores (P < 0.05), indicating the greatest incidence of loose stools. Pigs fed added ZnO had greater fecal DM than pigs fed the NC, 4% added wheat bran, or 18% CP diets, or with pigs fed the combination of additives intermediate (P < 0.01). These results suggest that adding pharmacological levels of Zn from ZnO improves nursery pig performance and increases DM content of feces when compared with pigs fed diets with either Na diformate, 4% course wheat bran, or 18% CP alone. However, a combination of all three alternatives appeared to be additive and partially restored growth performance similar to adding pharmacological levels of Zn.

Effects of feeding diets containing low crude protein and coarse wheat bran as alternatives to zinc oxide in nursery pig diets.

Two experiments were conducted to determine the effects of crude protein (CP) level in diets containing coarse wheat bran (CWB) with or without pharmacological levels of Zn (provided by zinc oxide: ZnO) on growth performance and fecal DM of nursery pigs. In experiment 1, 360 barrows (Line 200 × 400, DNA, Columbus, NE, initially 5.6 kg) were allotted to 1 of 6 dietary treatments from d 0 to 21 after weaning with 5 pigs per pen and 12 pens per treatment. Treatments included a positive control diet (21% CP) with 3,000 mg/kg Zn in phase 1 and 2,000 mg/kg in phase 2; negative control (21% CP) with 110 mg/kg added Zn, and 4 diets containing 4% CWB and 110 mg/kg added Zn formulated to contain 21%, 19.5%, 18%, or 16.5% CP. The 2 control diets and 21% CP CWB diet contained 1.40% standardized ileal digestible (SID) Lys in phase 1 and 1.35% SID Lys in phase 2, while the 19.5%, 18%, and 16.5% CP diets contained 1.33, 1.25 and 1.20% Lys, respectively, in both phases. Pigs fed the positive control diet containing pharmacological ZnO had increased (P < 0.05) ADG and G:F compared with the negative control and the 21% CP CWB diet. Reducing CP (concurrently with SID Lys) in diets containing CWB decreased ADG and G:F (linear, P = 0.002); however, fecal DM increased (linear, P = 0.005). In experiment 2, two groups of 300 and 350 pigs, initially 7.0 and 6.2 kg, respectively, were used with 5 pigs per pen and 26 pens per treatment. The objective was to determine if adding back essential AA would improve growth performance of pigs fed the low CP diets. All dietary treatments were fed for 13 days, contained 4% CWB, and consisted of: (1) positive control with 2,000 mg/kg of Zn and 21% CP (1.35% SID Lys); (2) no ZnO and 21% CP; and 3 diets with no ZnO formulated to 18% CP and (3) 1.2% SID Lys; (4) 1.35% SID Lys by the addition of feed grade amino acids (AA), and (5) diet 4 with non-essential amino acids (NEAA; Gly and Glu). Pigs fed 21% CP with ZnO had increased (P = 0.001) ADG compared to those fed 18% CP (1.35% SID Lys) with high levels of feed grade amino acids or those fed the reduced SID Lys (1.2%) diet. Overall, G:F was improved (P < 0.001) for pigs fed 21% CP diets and those fed the 18% CP diet with NEAA compared to pigs fed 1.2% SID Lys and pigs fed high levels of feed grade amino acids. Fecal DM was increased for pigs fed the reduced SID Lys diet. In summary, pharmacological levels of Zn improve pig growth performance, but reducing CP (and subsequently SID Lys) decreased nursery pig growth performance.

Effects of a multi-strain Bacillus subtilis-based direct-fed microbial on weanling pig growth performance and nutrient digestibility.

A study was conducted to evaluate the effects of a multi-strain Bacillus subtilis-based direct-fed microbial (DFM) on growth performance and apparent nutrient digestibility of nursery pigs. Eighty pigs, of equal number of barrows and gilts (initial body weight: 7.0 ± 0.60 kg), were weaned at 21 ± 1 d and randomly allotted to 1 of the 16 pens, with 5 pigs per pen. Two dietary treatments were implemented, a basal control (CON) and a control plus DFM (CDFM). Both diets were corn, soybean meal, and distillers dried grains based. Diets were fed for 42 d and growth performance measures were recorded weekly. On days 21 and 42 of the experiment, one pig per pen, with equal number of males and females, was randomly selected and euthanized. Digestibility of nitrogen (N), amino acids (AA), and energy were evaluated within the duodenum, jejunum, ileum, and ascending and distal colon. Relative to CON, CDFM tended to increase ADG during week 2 (P = 0.08) and significantly increased ADFI during week 2 (P = 0.04) and week 3 (P = 0.02). In addition, CDFM decreased the gain to feed ratio (G:F) during week 6 relative to CON (P = 0.04). Within the jejunum, pigs fed the DFM had greater digestibility of tryptophan (P = 0.04) and cysteine (P = 0.04) and tended to have greater digestibility of lysine (P = 0.07), methionine (P = 0.06), and threonine (P = 0.08), relative to CON. The content pH in the ascending colon did not differ between CDFM and CON. Compared with CON, apparent total tract digestibility (ATTD) of energy did not differ from CDFM, whereas ATTD of nitrogen of CDFM was lower (P = 0.05). The addition of a multi-strain B. subtilis-based DFM appears to impact growth performance, AA, and N digestibility depending upon the location in the gastrointestinal tract, with primary AA differences occurring within the mid-jejunum.

Low-tannin sorghum grain could be used as an alternative to corn in diet for nursery pigs.

This study was conducted to test the hypothesis that low-tannin sorghum grain produced in China as a potential substitute for corn in diets could not impair the performance of nursery pigs. A total of 60 pigs (7.2±1.2kg) were randomly assigned to 2 diets with 5 replicate pens per treatment. Corn-based diet (CBD) included 60% corn grain during the overall experimental period, and sorghum-based diet (SBD) consisted of 30% (d 1 to 14) or 60.55% (d 15 to 28) sorghum grain in partial or total replacement of corn grain. Both diets were formulated to contain the same amount of digestible energy and indispensable amino acids. The results demonstrated no differences in growth performance or apparent digestibility of gross energy between treatments over the whole period. However, the substitution of corn by sorghum reduced (p<0.05) or tended to reduce (p=0.09) apparent digestibility of crude protein associated with an increased faecal nitrogen excretion per weight gain (p<0.05). Pigs fed SBD had higher contents of urea nitrogen, total triglyceride and insulin in serum than those fed CBD (p<0.05). Visceral organ weights or antioxidant enzyme activities in serum or liver were not different between treatments. Compared with CBD, SBD increased or tended to increase amylase activity in jejunal mucosa (p<0.05) or trypsin activity in duodenal mucosa (p=0.08). Replacement of corn by the low-tannin sorghum in diets did not influence the microbiota community based on alpha and beta diversity in caecal and colonal digesta. Overall, the home-grown low-tannin sorghum could be an alternative energy source in diets for pigs without adverse effects on growth performance.

The Effects of Feeding Antibiotic on the Intestinal Microbiota of Weanling Pigs.

This study investigated the use of carbadox in the diet of nursery pigs. Ten pens of weanling piglets were assigned to 2 treatments: one containing carbadox and another without it. From days 21 to 35 of age, the first group of piglets was fed carbadox at 55 mg/kg of diet; followed by 27.5 mg/kg from days 36 to 49; and 0 mg/kg from days 50 to 63. The second group of pigs was fed a control diet without carbadox from days 21 to 63 of age. On days 35, 49, and 63, fecal samples were collected directly from the rectum of 2 piglets in each pen, and the samples were subjected to microbial DNA sequencing and metagenomic functional analysis using the 16S rRNA gene. Feed conversion from days 21 to 63 was improved (P = 0.04) in the group of piglets fed carbadox. Faith's phylogenetic diversity was similar (P = 0.89) for both groups of piglets on day 35, but it was diminished (P = 0.01) in the carbadox-fed group on day 49; however, following the complete removal of carbadox from their diets, this microbial diversity index was once again found to be similar (P = 0.27) in both groups on day 63. Likewise, abundances of Slackia, Peptococcus, Catenibacterium, Coprococcus, and Blautia were all similar between the two groups (P ≥ 0.40) on day 35, but were smaller in the carbadox group (P ≤ 0.05) on day 49; however, on day 63, abundances of all these genera were once again similar (P ≥ 0.29). Metabolic pathways involved in cellular growth, death, and genetic information processing (translation) were found to be similarly expressed in the microbiota of piglets from both groups on day 35 (P ≥ 0.52), but decreased in the carbadox group on day 49 (P ≤ 0.05), and were similar again in both groups on day 63 (P ≥ 0.51). These results revealed that feeding carbadox to piglets during the first 4 weeks after weaning significantly affected their fecal microbiotas; however, 2 weeks after the removal of carbadox, those changes tended to disappear, indicating that the shifts were carbadox-dependent.

Comparative efficacy of commercially available deoxynivalenol detoxifying feed additives on growth performance, total tract digestibility of components, and physiological responses in nursery pigs fed diets formulated with naturally contaminated corn.

Comparative efficacy of deoxynivalenol (DON) detoxifying feed additives (FA) was evaluated in growth performance (exp. 1) and apparent total tract digestibility (ATTD; exp. 2) nursery pig studies. Six corn–soybean meal-based diets were used: 1) positive control (PC, formulated with <1.5 ppm DON corn), negative control (NC, formulated with 5.5 ppm DON corn), NC + FA1 (clay plus yeast cell wall extract), NC + FA2 (aluminosilicate), NC + FA3 (aluminosilicate plus fungal extract), and NC + FA4 (sodium metabisulfite, SMB). In exp. 1, 144 pigs (body weight [BW], 10.2 ± 0.1kg) were housed (4 pigs/pen), allocated to diets (n = 6) based on BW, and fed for 4-wk. The BW and feed intake were monitored weekly. On d 7, one pig/pen was bled for plasma and euthanized for organ weight and tissue samples. Assayed DON concentration in PC, NC, NC + FA4 was 0.29, 2.86, and 1.21 ppm, respectively. In wk-1, the average daily gain (ADG) of pigs fed NC + FA4 was not different (P > 0.05) to that of pigs fed PC diet but greater (P = 0.01) than for pigs fed NC without or with other FA. Pigs fed NC and NC + FA2 had lower (P = 0.026) average daily feed intake (ADFI) than pigs fed PC and NC + FA3. Pigs fed NC + FA4 had greater (P = 0.003) G:F than pigs fed the other diets. Diets had no effect (P > 0.05) on ADG, ADFI, and G: F after first week, plasma concentration of urea and creatinine or liver and spleen weight. Pigs fed NC diets had greater (P = 0.01) jejunal mRNA expression of superoxide dismutase 1 relative to pigs fed PC or NC plus FA. Jejunal histomorphology and mRNA expression of nutrient transporters, inflammatory cytokines, and tight junction proteins and ceca digesta concentration of short-chain fatty acids were not affected (P > 0.05) by the diet. In exp. 2, 24 barrows (BW 10.2 ± 0.3 kg) were individually placed in metabolism crates and allocated to four diets: PC, NC, NC + FA3, and NC + FA4 (n = 6) containing TiO2 as digestibility marker. Pigs were adjusted to diets for 5 d, followed by a 2-d grab fecal sample collection. Pigs fed PC and NC + FA4 diets had higher ATTD of dry matter, gross energy, and crude protein than NC fed pigs. The FA3 was intermediate in digestibility response. In conclusion, FA containing sequestering component plus fungal extract or SMB in DON-contaminated feed resulted in commensurate nursery pig performance to PC. The tested FA mitigated intestinal oxidative stress through decreased expression of genes for superoxide dismutase.

Evaluating dietary acidifiers as alternatives for conventional feed-based antibiotics in nursery pig diets.

A total of 360 weanling pigs (DNA 200 × 400; initially 9.7 ± 0.23 kg BW) were used in a 21-d experiment with 6 pigs/pen, 10 replicate pens/treatment, and 2 separate nursery rooms, each with 30 pens. Pigs were weighed and allotted to pens based on BW in a completely randomized block design to one of six treatment diets: 1) Negative control (no organic acids or antibiotics) and the control with 2) 0.25% acidifier A; 3) 0.3% acidifier B; 4) 0.5% acidifier C); 5) 50 g/ton carbadox; and 6) 400 g/ton chlortetracycline (CTC). Upon weaning, a common diet with no antibiotics or additives was fed for 21 d (Phases 1 and 2; days −21 to 0), followed by a 21-d experimental period (Phase 3; days 0 to 21) where treatment diets were fed. Pigs and feeders were individually weighed on a weekly basis to calculate average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F). Data were analyzed using the PROC GLIMMIX procedure of SAS (v 9.4, SAS Inst., Cary, NC) with pen as the experimental unit, treatment as a fixed effect, and room as a random effect. Dietary treatment had a significant impact (P < 0.05) on ADG, ADFI, and G:F each week and for the overall experimental period (days 0 to 21). Specifically, from days 0 to 7, pigs fed CTC had increased (P = 0.001) ADG compared with those fed acidifier B, acidifier C, and carbadox, whereas pigs fed the negative control and acidifier A diets were intermediate. Additionally, pigs fed the CTC diet had improved (P = 0.0002) ADFI when compared with all other treatments. From days 7 to 14 and days 14 to 21, pigs fed the carbadox diet had decreased (P < 0.0001) ADG compared with all other treatments. During the overall period (days 0 to 21), pigs fed diets containing carbadox had reduced ADG and ADFI (P < 0.0001), whereas pigs fed CTC had improved (P < 0.0001) ADG compared with all other treatments. Additionally, blood parameters, fecal consistency, and fecal microbial populations were analyzed on a subset of pigs (n = 5 pigs/treatment). Dietary treatment significantly affected (P < 0.05) concentrations of protein, globulin, phosphorus, alkaline phosphatase, and sorbitol dehydrogenase in the blood. Treatment also significantly impacted (P = 0.0005) fecal score but did not affect (P = 0.59) fecal microbial growth from days 0 to 21. In summary, CTC continues to be a valuable additive to improve performance in the nursery. Further investigation surrounding the efficacy of dietary acidifiers as antibiotic alternatives is warranted given inconclusive evidence in this study.