The effect of supplementation of essential amino acid combinations in a low crude protein diet on growth performance in weanling pigs

The present study investigated the impact of providing different supplemental essential amino acids (EAA) in a low crude protein (CP) diet on growth performance in weanling pigs. A total of 324 mixed-sex 24-d weaned piglets (initial BW 6.9 ± 0.34 kg) were used in a 27-d growth trial with six dietary treatments immediately post-weaning. The first two treatments were a control standard CP (19%) diet (positive control; PC) and a negative control (NC) diet with low CP (16%) and reduced Ile, Leu, and histidine levels. The rest of the treatments had low CP with varied EAA types and levels; T1 had similar Ile, Leu, and His levels as PC but with low CP (16%), while T2 had low CP and 10% higher His, Thr, Trp, and Met+Cys compared to PC. The T3 was a low CP diet with 10% supplemental Leu, Ile, and Val compared to PC, while T4 was a low CP diet with 10% supplementation with all the EAA except Lys compared to PC. The initial body weight (BW) was not statistically different (P > 0.05) among the treatments. Also, on d 6, no statistical differences in BW were observed among the treatments. The average BW recorded on d 13, 20, and 27 showed significant treatment differences where the PC had consistently higher BW than all the other treatments (P < 0.05). The average daily gain (ADG) of the PC was higher than the rest of the treatments. Between d 13 and 20, the average daily feed intake (ADFI) for PC was not different from NC and T1 (P > 0.05), but compared to T2, T3, and T4, the PC treatment showed a high ADFI (P < 0.05). Overall (d 0-27), the ADFI for PC was not different from T1 and was significantly higher than all other treatments. Overall, results showed that the gain to feed (G:F) ratio was higher (P < 0.05) for PC compared to other dietary treatments. In summary, although the treatments (T1-T4) consisted of varying levels of EAA above the recommended requirement levels for optimal performance, we did not see a significant impact on growth performance improvement, which may indicate that the targeted EAA (His, Val, Thr, lle, Leu, Trp, and Met) may not have been limiting in these diets. On the other hand, the phenylalanine (Phe) requirement may be limited in the current formulations, or perhaps the EAA: total N ratio in T1, T2, T3, and T4 may have been too high, resulting in the inefficiency of EAA utilization for growth.

Effect of the essential amino acid-nitrogen to total nitrogen ratio on lysine requirement for nitrogen retention in growing pigs

Low protein diets supplemented with essential amino acids (EAA) fed to pigs reduce the excess supply of EAA and nitrogen (N). However, low protein diets may become limiting in non-essential amino acids (NEAA) and N, thus affecting the utilization of EAA for N retention. It has been suggested that the EAA-N:total N (E:T) ratio can give an indication of dietary N sufficiency. An N-balance study was conducted to determine the effect of E:T ratio on the Lys requirement for maximum N retention. A total of 80 growing barrows (19.3 ± 0.21 kg initial body weight) were randomly assigned to 1 of 10 diets (n = 8) in 8 blocks in a 2 × 5 factorial arrangement. Diets consisted of a low ratio (LR; E:T of 0.33) or a high ratio (HR; E:T of 0.36) with graded Lys content (0.82%, 0.92%, 1.02%, 1.12%, and 1.22% standardized ileal digestible [SID]). After a 7-d adaptation, a 4-d N-balance collection was conducted. Blood samples were obtained on d 2 of the collection period 2 h after the morning meal for plasma urea N (PUN) analysis. Data were analyzed using the MIXED model procedure with fixed effects of ratio (n = 2), Lys (n = 5), and their interactions. The experimental block (room) was included as a random effect (n = 8). The SID Lys requirement was estimated using PROC NLIN linear broken-line breakpoint model. There was a significant interaction between E:T ratio and Lys (P < 0.01), where LR diets had a higher N retention than HR diets, while increasing Lys linearly increased N retention (P = 0.01) in both HR and LR diets. The marginal efficiency of utilizing SID Lys (P < 0.01) reduced with increasing Lys content, while the efficiency of utilizing N (P < 0.05) increased as Lys increased. The SID Lys required to maximize N retention of pigs fed HR diets was estimated at 1.08% (R2 = 0.61) and LR diets at 1.21% (R2 = 0.80). The current results indicate that N may be limiting in diets with a high E:T ratio, limiting N retention. Supplying additional dietary N, as intact protein, can increase N retention, resulting in a greater Lys requirement.

Serum metabolomic characterization in pigs in relation to birth weight category and neonatal nutrition

The objective of this study was to characterize developmental differences in low birth weight (LBW) and normal birth weight (NBW) piglets with or without pre-weaning nutrient restriction using serum metabolomic profile analysis. At farrowing, 112 piglets were identified as LBW (1.22 ± 0.28 kg) or NBW (1.70 ± 0.27 kg) and were randomly assigned to receive normal nutrition (NN) or restricted nutrition (RN) (6 h/day no suckling) from days 2 to 28 post farrow (n = 8 pigs/group). On day 28, piglets were weaned onto a common diet. Fasted blood samples were obtained on days 28 and 56 (n = 8 pigs/group) and were analyzed using quantitative metabolomics via a combination of direct injection mass spectrometry with a reverse-phase LC-MS/MS custom assay. Data were normalized using logarithmic transformation and auto-scaling. Partial least squares discriminant analysis (PLS-DA) was carried out to further explore the differential metabolites among the groups (metaboanalyst.ca) with an integrated enrichment and pathway topography analysis. On day 28, LBW piglets had lower levels of essential amino acids as well as reduced metabolites associated with fatty acid oxidation, glycolysis, and the tri-carboxylic acid (TCA) cycle compared to the NBW group. The overall reduction of metabolites associated with energy production and regulation suggests that LBW vs. NBW are in an energy-survival state. On day 56, LBW pigs had increased utilization of fatty acids and resultant ketone production, evident by increased carnitines, acetoacetate, β-hydroxybutyrate, and glycerol compared to NBW pigs. In addition, compared to the NBW pigs LBW pigs had a consistent decrease in serum glucose and lactate as well as reduced TCA cycle metabolites: pyruvate, succinate, citrate, and α-ketoglutaric acid similar to day 28. Low reliance on glycolysis and the TCA cycle and higher glycerol production in the LBW pigs may indicate impairments in glucose tolerance at 56 d. In summary, LBW piglets appear to have more metabolic alterations in early life, which is not resolved with adequate nutrition or refeeding and may elucidate physiological and metabolic mechanisms of poor growth and life performance compared to NBW pigs later in life.

Impact of L-Arginine and L-Glutamine supplementation on growth performance and immune status in weanling pigs challenged with Escherichia coli F4

Arginine (ARG) and Glutamine (GLN) have been reported to play significant roles in protein metabolism, immunity, and intestinal health in weanling pigs. The present study investigated the independent and interactive effect of supplementing ARG and GLN on pigs immune status and growth performance following an Escherichia coli F4 challenge. A total of 240 mixed-sex pigs (24 ± 2 d old; 7.3 ± 0.1 kg BW) were used in a 42-d experiment after selection for E. coli F4 susceptibility. The pigs were group-housed (3 pigs per pen), and pens were randomly assigned to five experimental treatments (N = 16 pens per treatment). Experimental treatments were: 1) a wheat-barley-soybean meal-based basal diet (CTRL), 2) a basal diet with 2500 mg/kg zinc oxide (ZnO), 3) a basal diet + 0.5% Glutamine (0.5% GLN), 4) basal diet + 0.5% Arginine (0.5% ARG), and 5) basal diet with 0.5% Glutamine + 0.5% Arginine (0.5% GLN + ARG). All Pigs were inoculated with E. coli F4 on days 7, 8, and 9 post-weaning. Rectal swabs were taken from each pig and plated on blood agar plates for E. coli F4 presence. Blood and fecal samples were taken to determine the acute phase response and selected fecal biomarkers for the immune response. Growth performance and fecal scores were recorded. Fecal swabs resulted in no positive pig for E. coli F4 before inoculation and 73.3% positive postinoculation. Diarrhea incidence during days 7 to 14 was significantly lower for the ZnO treatment (P < 0.05). The haptoglobin level on day 3 was lower than days 10 and 20, irrespective of treatment (P < 0.05). The albumin level was lower on day 20 compared to days 3 and 10 (P < 0.05). There was no treatment effect on albumin levels regardless of sampling day (P > 0.05). The PigMAP was lowest on day 3 and highest on day 10 (P < 0.05). We did not observe significant treatment differences (P > 0.05) in myeloperoxidase and calprotectin. Pancreatitis-associated protein was higher in the ZnO (P = 0.001) treatment than in the other treatments. Fecal IgA tended (P = 0.10) to be higher in the ZnO and 0.5% ARG treatments. There were no performance differences, except during days 0 to 7, where the ZnO treatment was lower in average daily gain and average daily feed intake (P < 0.001), while feed efficiency (G:F) FE was similar across treatments. In summary, no improved performance was observed with either ARG, glutamate, or both. The immune response results showed that the E. coli F4 challenge may have exacerbated the acute phase response; hence, the benefits of dietary treatments did not go beyond immune repair and reduction in inflammation.

PSVI-4 Serum Metabolomic Characterization of Birth Weight and Neonatal Nutrient Restriction on Piglet Growth and Development

The objective was to characterize developmental differences in low birth weight (LBW) and normal birth weight (NBW) piglets with or without nutrient restriction using serum metabolomic profile analysis. After farrowing, 112 piglets were selected as LBW (1.22 ± 0.28 kg) or NBW (1.70 ± 0.27 kg) and were categorized to receive normal nutrition (NN) or restricted nutrition (RN - 6 h/day no suckling) until d 28 when the pigs were weaned onto a common diet until d 56. Blood samples were taken on d 28 and d 56 (n=8 pigs/treatment) and were analyzed using quantitative metabolomics via a combination of direct injection mass spectrometry with a reverse-phase LC-MS/MS custom assay (TMIC prime). Data were normalized using logarithmic transformation and auto-scaling. Partial least squares discriminant analysis (PLS-DA) was carried out to further explore the differential metabolites among the treatments (metaboanalyst.ca) with an integrated enrichment and pathway topography analysis. The results suggest that at d 28, LBW piglets had decreased metabolites associated with fatty acid oxidation, glycolysis and TCA cycle metabolites, and essential amino acids such as valine, leucine, arginine. These indicate a decrease utilization of gluconeogenic, and TCA cycle pathways compared with the NBW group. On d 56, LBW piglets had increased utilization of fatty acids, exhibited by increased production of serum acetoacetate, B-hydroxybutyrate, glycerol, compared with NBW. Additionally, the LBW piglets had decreased glucose utilization, pyruvate, succinate, citrate, a-ketoglutaric acid, and lactate compared with the NBW piglets. Due to low utilization of glycolysis and the TCA cycle, associated amino acids were less in LBW piglets, except for a increased glycerol which may indicate impairments in glucose tolerance. In summary, LBW piglets appear to have more metabolic deficiencies in early life, which is not resolved with nutrition in early life, but may be responsive to a tailored nutritional intervention post-weaning.

Pre- and post-weaning performance of piglets offered different types of creep feed

We determined the impact of creep feed provision and type on pre- and post-weaning growth performance of piglets. At 2 wk post farrow, litters (n = 50) were given no creep feed or provided a simple creep feed, a complex creep feed, or both until weaning at ∼28 d. Creep feed, regardless of type, resulted in increased growth (P < 0.05) of piglets in the final week pre-weaning and immediate week post-weaning, which was not maintained at the end of the nursery period. Piglets showed no preference for creep feed type (P > 0.05).

Ileal alkaline phosphatase is upregulated following functional amino acid supplementation in Salmonella Typhimurium-challenged pigs

We recently showed that functional amino acid (FAA) supplementation improves growth performance and immune status of Salmonella Typhimurium (ST)-challenged pigs, which was further improved by a longer adaptation period. It is expected that the effects are associated with increased activity of intestinal alkaline phosphatase (IAP). The objective of this study was to evaluate the effects of FAA supplementation and adaptation period on the ileal, cecal, and colonic activity of IAP in weaned pigs challenged with ST. In experiment 1, a total of 32 mixed-sex weanling pigs were randomly assigned to dietary treatments in a 2 × 2 factorial arrangement with low (LP) or high protein (HP) content and basal (FAA-) or FAA profile (FAA+; Thr, Met, and Trp at 120% of requirements) as factors. In experiment 2, a total of 32 mixed-sex weanling pigs were randomly assigned to one of four dietary treatments, being FAA- fed throughout the experimental period (FAA-) or an FAA profile fed only in the post-inoculation (FAA + 0), for 1 wk pre- and post-inoculation (FAA + 1), or throughout the experimental period (FAA + 2). In experiments 1 and 2, after a 7- and 14-d adaptation period, respectively, pigs were inoculated with saline solution containing ST (3.3 and 2.2 × 109 CFU/mL, respectively). Plasma alkaline phosphatase was measured on days 0 and 7 post-inoculation in experiment 1, and IAP (ileum, cecum, and colon) was measured in experiments 1 and 2. Correlations among ileal IAP and serum albumin and haptoglobin, plasma superoxide dismutase (SOD), malondialdehyde (MDA), and reduced:oxidized glutathione, ileal myeloperoxidase, ST shedding and ileal colonization, and post-inoculation average daily gain, feed intake (ADFI), and gain:feed were also analyzed. In experiment 1, plasma alkaline phosphatase was decreased with ST inoculation and the overall content was increased in LP-FAA+ compared with LP-FAA- (P < 0.05). Moreover, ileal IAP was increased in FAA+ compared with FAA- pigs in both studies (P < 0.05) regardless of adaptation time (P > 0.05). IAP was positively correlated with MDA and ADFI and negatively correlated with SOD and ST shedding in experiment 1 (P < 0.05). These results demonstrate a positive effect of FAA supplementation, but not adaptation period, on ileal alkaline phosphatase activity in Salmonella-challenged pigs, which may be associated with improvements in antioxidant balance.

Birth Weight and Nutrient Restriction Affect Jejunal Enzyme Activity and Gene Markers for Nutrient Transport and Intestinal Function in Piglets

Simple Summary

Birth weight and nutrient utilization are thought to have significant effects on intestinal development in neonatal pigs. The present study evaluated the impact of low and normal birth weight with and without nutrient restriction during the neonatal period on jejunal development. The results observed suggest that during the first 28 d of life, birth weight had greater effects on intestinal development than nutrient level, however, at d 56, the nutrient level was a significant contributor to intestinal function and enzyme activity compared to birth weight. Taken together, both birth weight and nutrient restriction have effects on intestinal development, but may have a greater impact in early life (d 28).

Abstract

Significant variation in the birth weight of piglets has arisen due to increased sow prolificacy. Intestinal development and function may be affected by birth weight. Low birth weight (LBW) pigs may also have reduced feed intake, leading to further impairment of intestinal development. The objective of this study was to examine the intestinal development pattern of LBW and normal birth weight (NBW) piglets with normal nutrition (NN) or restricted nutrition (RN) in the pre-weaning period. Jejunal intestinal samples were analyzed for target gene expression and enzyme activity at d 28 (weaning) and d 56 (post-weaning). At d 28, excitatory amino acid transporter (EAAC1) and sodium-dependent neutral amino acid transporter (B⁰AT1) were downregulated in LBW compared to NBW pigs (p < 0.05). On d 56, B⁰AT1 and ASCT2 (glutamine transporter) were downregulated in RN compared to NN pigs (p < 0.05), regardless of birth weight. Peptide transporter 1 (PepT1) expression was downregulated in LBW compared to NBW pigs at 28 d (p < 0.05), with no effects of treatments at 56 d. Sodium-glucose transporter-1 (SGLT1) was upregulated in NBW-NN compared to LBW-NN pigs (p < 0.05) at 28 d. Alkaline phosphatase (ALP) was upregulated in LBW-RN at d 28. At d 56, claudin-3 (CLDN-3) and Zonular occludin-1 (ZO-1) were upregulated in NN compared to RN pigs (p < 0.05). There were no treatment effects on ALP, maltase, or sucrase activity at 28 d. However, at 56 d, ALP was upregulated in NBW-NN pigs while sucrase activity was upregulated in NN pigs (p < 0.05). The results demonstrate differences in jejunal gene expression associated with birth weight, with reduced gene expression of amino acid transporters (PepT1, EAAC1, B⁰AT1) in LBW compared to NBW pigs (p < 0.05). While neonatal nutrient restriction had minimal effects at 28 d and d 56 for tight junction protein transcript abundance, neutral amino acid transporter abundance was upregulated in NN pigs compared to RN piglets (p < 0.05).

Effect of long-term feeding of graded levels of deoxynivalenol on performance, nutrient utilization, and organ health of grower-finisher pigs (35 to 120 kg)

The objective of this study was to evaluate the effect of long-term feeding of graded levels of deoxynivalenol (DON) on performance, nutrient utilization, and organ health of grower-finisher pigs. A total of 240 mixed-sex grower-finisher pigs (35.9 ± 1.1 kg initial body weight, BW) were randomly assigned to 1 of 4 dietary treatments (6 pigs/pen; 10 pens/treatment) for 77 d. Diets consisted of a control diet without DON (CONT) and diets containing 1, 3, or 5 ppm DON (DON1, DON3, or DON5). Nitrogen-balance was determined in 1 pig/pen during weeks 6 and 12 of the study. Growth performance measures were taken weekly for average daily feed intake (ADFI), average daily gain (ADG), and gain:feed (GF) until day 77. Blood samples were collected on days 0, 14, 42, 56, and 84 from 1 pig/pen for analysis of indicators of liver and kidney function. On day 7, ADG and ADFI for pigs fed DON3 and DON5 diets were lower (P < 0.05) compared with DON1- and CONT-fed pigs. Overall, ADG and ADFI (days 0 to 77) were lower in DON3- and DON5-fed pigs compared with CONT and DON1 pigs (P < 0.05), with no difference in GF (P > 0.05). Final BW was reduced in DON3- and DON5-fed pigs (P < 0.05) compared with CONT and DON1, which were not different (P > 0.05). No significant (P > 0.05) treatment effects were observed on carcass characteristics. In the grower-phase, protein deposition (PD) was reduced in DON3 and DON5 pigs compared with CONT and DON1 pigs (P < 0.05). In the finisher phase, PD was not affected by dietary treatment (P > 0.05). There was no effect of dietary treatment on the majority of selected serum chemistry (P > 0.05). In summary, pigs exposed to diets containing > 1 ppm DON had reduced growth performance with little or no effect on nitrogen utilization, organ health, or carcass characteristics, suggesting that the negative effects of DON may be largely due to depressed feed intake.

Factors affecting performance response of pigs exposed to different challenge models: a multivariate approach

Factors associated with the severity with which different challenge models (CMs) compromise growth performance in pigs were investigated using hierarchical clustering on principal components (HCPC) analysis. One hundred seventy-eight studies reporting growth performance variables (average daily gain [ADG], average daily feed intake [ADFI], gain:feed [GF], and final body weight [FBW]) of a Control (Ct) vs. a Challenged (Ch) group of pigs using different CMs (enteric [ENT], environmental [ENV], lipopolysaccharide [LPS], respiratory [RES], or sanitary condition [SAN] challenges) were included. Studies were grouped by similarity in performance in three clusters (C1, C2, and C3) by HCPC. The effects of CM, cluster, and sex (males [M], females [F], mixed [Mi]) were investigated. Linear (LRP) and quadratic (QRP) response plateau models were fitted to assess the interrelationships between the change in ADG (∆ADG) and ADFI (∆ADFI) and the duration of challenge. All variables increased from C1 through C3, except for GF, which decreased (P < 0.05). LPS was more detrimental to ADG than ENV, RES, and SAN models (P < 0.05). Furthermore, LPS also lowered GF more than all the other CMs (P < 0.05). The ∆ADG independent of ∆ADFI was significant in LPS and SAN (P < 0.05), showed a trend toward the significance in ENT and RES (P < 0.10), and was not significant in ENV (P > 0.10), while the ∆ADG dependent on ∆ADFI was significant in ENT, ENV, and LPS only (P < 0.05). The critical value of ∆ADFI influencing the ∆ADG was significant in pigs belonging to C1 (P < 0.05) but not C2 or C3 (P > 0.10). The ∆ADG independent of duration post-Ch (irreparable portion of growth) was significant in C1 and C2 pigs, whereas the ∆ADFI independent of duration post-Ch (irreparable portion of feed intake) was significant in C1 pigs only (P < 0.05). Moreover, the time for recovery of ADG and ADFI after Ch was significant in pigs belonging to C1 and C2 (P < 0.05). Control F showed reduced ADG compared with Ct-M, and Ch-F showed reduced ADFI compared with Ch-M (P < 0.05). Moreover, the irreparable portion of ΔADG was 4.8 higher in F (-187.7; P < 0.05) compared with M (-39.1; P < 0.05). There are significant differences in growth performance response to CM based on cluster and sex. Furthermore, bacterial lipopolysaccharide appears to be an appropriate noninfectious model for immune stimulation and growth impairment in pigs.

Microbial sensing in the neonatal pig gut: effect of diet-independent and diet-dependent factors1

There is considerable agreement that the gastrointestinal microbiota contributes to the performance and health of the neonate, and this relationship includes an ability of the host animal to “sense” changes in the microbial community. Identifying the mechanisms used by the host to sense microbiota is one approach to developing methods to manipulate the microbiota to improve pig health and performance. Diet-independent microbial products are molecules unique to the microbial community and sensed by host pattern recognition receptors stimulating inflammation. Common among all members of the microbial community, their presence is unaffected by diet, but the nature of the response does depends on factors affecting the microenvironment in which the molecule is detected. Diet-dependent microbial products arise as products of fermentation of dietary components and include short-chain fatty acids, ammonia, phenols, hydrogen sulfide, amines, and many other compounds. A plethora of sensing mechanisms exists that include enzymatic metabolism as well as membrane receptors that have evolved to respond to microbial products (e.g., short-chain fatty acid receptors), or simply cross-react with microbial products. This review focuses on host mechanisms used to sense the intestinal microbiota and attempts to establish practical considerations for neonatal gut health based on current understanding.

PSV-4 Determination of Deoxynivalenol (DON) Content in Biological Samples as an Indicator of DON Intake in Grower-finisher Pigs

Due to difficulties in obtaining consistent and/or reliable measures of deoxynivalenol (DON) in complete swine diets, we investigated whether measuring DON in biological samples could be used as an indicator of DON ingestion in pigs. In this study, graded levels of DON (1, 3, or 5 ppm) were fed to grower-finisher pigs for a period of 77-d. On d 35 and 77 of the study, urine samples were quantitatively collected over a 24-h period and blood samples were collected between 3 – 4 h after the morning meal on each of those days for serum DON analysis. For direct quantification of DON in urine, high-performance liquid chromatography with tandem mass spectrometry was performed. For serum samples, indirect quantification of DON was performed via enzymatic hydrolysis. We observed that DON content in urine increased linearly as intake of DON increased (Fig.1A; P &lt; 0.05). Analysis of DON in serum follow a similar trend, where serum DON content was increased as DON intake increased (Fig.1B; P &lt; 0.05). An average of 30% of DON ingested was recovered as DON in urine over a 24-h period. In summary, there was a linear relationship between DON intake and DON content in both urine and blood serum, therefore, analyzing DON concentration in serum and urine could be used as a tool to estimate for DON exposure in pigs under controlled conditions.

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210 A Longer Adaptation Period to a Functional Amino Acid-supplemented Diet Improves Growth Performance and Attenuates Acute-phase Response in Salmonella Typhimurium-challenged Pigs

Functional amino acid supplementation during disease challenge enhances growth performance and immune status. The present study investigated the effect of duration of adaptation period to a functional amino acid (FAA)-supplemented diet on growth performance and immune status during a subsequent Salmonella challenge in pigs. Thirty-two mixed-sex weanling pigs (8 pigs/treatment; 11.6 ± 0.34 kg initial body weight) received either a basal diet without FAA supplementation throughout the experimental period (FAA-) or a diet containing a supplemented FAA profile (Thr, Met, and Trp at 120% of requirements) fed for either 0 (FAA+0), 1 (FAA+1) or 2 (FAA+2) wk pre- and 1 wk post-inoculation with Salmonella Typhimurium (ST). Pigs were orally inoculated with saline containing ST after the 2 wk pre-inoculation period and monitored for 1 wk post-inoculation. Pigs had ad libitum access to diets throughout the experiment. Performance parameters [average daily gain (ADG), feed intake, and gain:feed (GF)] were measured in the pre- and post-inoculation periods. Blood samples were collected on d 0, 4, and 7 post-inoculation for serum haptoglobin and albumin analysis. There was no effect of diet on pre-inoculation performance (P &gt; 0.05). Post-inoculation, FAA+2 pigs had the highest ADG (0.46 kg/d) and GF (0.63 kg/kg), FAA- the lowest (0.21 kg/d; 0.29 kg/kg), with FAA+0 (0.33 kg/d; 0.46 kg/kg) and FAA+1 (0.40 kg/d; 0.53 kg/kg) being intermediate (ADG, P &lt; 0.05, SEM=0.059; GF, P &lt; 0.05, SEM=0.099). Overall, albumin was higher in FAA+2 (35.25 g/L) and FAA+1 (34.63 g/L) pigs compared to FAA+0 (30.38 g/L) and FAA- (29.67 g/L) pigs (P &lt; 0.05, SEM=0.717). Furthermore, FAA+2 pigs had the lowest overall haptoglobin (0.90 g/L), FAA- the highest (1.54 g/L), with FAA+0 (1.32 g/L) and FAA+1 (1.06 g/L) being intermediate (P &lt; 0.05, SEM=0.111). In conclusion, a longer adaptation period to FAA supplementation improved performance and attenuated the immune response of pigs when exposed to an enteric disease challenge.

A longer adaptation period to a functional amino acid-supplemented diet improves growth performance and immune status of Salmonella Typhimurium-challenged pigs

We recently showed that dietary supplementation with key functional amino acids (FAA) improves growth performance and immune status of Salmonella Typhimurium (ST)-challenged pigs. It is not known if ST-challenged pigs will benefit from a longer adaptation period to FAA. The objective of this study was to evaluate the effects of different adaptation periods to diets containing FAA above requirements for growth on performance and immune response of weaned pigs subsequently challenged with ST. A total of 32 mixed-sex weanling pigs (11.6 ± 0.3 kg) were randomly assigned to 1 of 4 dietary treatments, being a basal amino acid (AA) profile fed throughout the experimental period (FAA-) or a functional AA profile (FAA+; Thr, Met, and Trp at 120% of requirements) fed only in the postinoculation (FAA+0), for 1 wk pre- and postinoculation (FAA+1), or throughout the experimental period (FAA+2). After a 14-d adaptation period, pigs were inoculated with ST (2.15 × 109 CFU/mL). Growth performance, body temperature, fecal score, acute-phase proteins, oxidant/antioxidant balance, score for ST shedding in feces and intestinal colonization, and fecal and digesta myeloperoxidase (MPO) were measured pre- and postinoculation. Postinoculation body temperature and fecal score, serum haptoglobin, plasma superoxide dismutase (SOD), malondialdehyde (MDA), and fecal MPO were increased while serum albumin and plasma reduced glutathione (GSH):oxidized glutathione (GSSG) were reduced compared to pre-inoculation (P < 0.05). Average daily gain and G:F were greater in FAA+2 pigs compared to FAA- pigs (P < 0.05). Serum albumin was higher in FAA+2 and FAA+1 compared to FAA+0 and FAA- pigs (P < 0.05) while FAA+2 pigs had lower haptoglobin compared to FAA- (P < 0.05). Plasma SOD was increased and GSH:GSSG was decreased in FAA- pigs compared to the other treatments (P < 0.05). Score for ST shedding in feces was progressively lower from d 1 to 6 regardless of treatment (P < 0.05) and was lower in FAA+2 pigs compared to FAA- and FAA+0 (P < 0.05). Counts of ST in colon digesta were higher in FAA- and FAA+0 pigs compared to FAA+2 (P < 0.05). Fecal and colonic digesta MPO were lower in FAA+2 and FAA+1 pigs compared to FAA- (P < 0.05). These results demonstrate a positive effect of a longer adaptation period to FAA-supplemented diets on performance and immune status of weaned pigs challenged with Salmonella.

Effect of long-term feeding of graded levels of deoxynivalenol (DON) on growth performance, nutrient utilization, and organ health in finishing pigs and DON content in biological samples

The prevalence of deoxynivalenol (DON) is a concern for swine producers, and although there has been extensive research into the effects of DON in pigs, focus has been in young pigs and/or in short-term studies. The objective of the study was to determine the effect of long-term exposure to DON-contaminated diets in finisher pigs. A total of 200 pigs (76.6 ± 3.9 kg initial weight) were group housed (five pigs per pen; n = 10 pens/treatment) in a 6-wk trial. Pigs were fed a wheat-barley-soybean meal-based control (CONT) diet with no DON or the basal diet in which clean wheat was replaced by DON-contaminated wheat and wheat screenings to provide DON content of 1, 3, or 5 ppm (DON1, DON3, and DON5, respectively). Individual BW and pen feed intake were recorded weekly to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F). Blood was collected on days 0, 14, and 43 and analyzed for indicators of liver and kidney health. Nitrogen (N)-balance was conducted immediately following the growth performance period to determine the effect of DON on nutrient utilization. Blood and urine samples collected during N balance were analyzed for DON content. Feeding DON reduced (P < 0.05) ADFI and ADG from days 0 to 28 compared with CONT, after which there was no effect of diet on ADFI and ADG. The G:F was lower (P < 0.05) in DON5 fed pigs compared with all treatments during days 0 to 7; however, no treatment effects on G:F was observed from days 8 to 42. Nitrogen retention was lower (P < 0.05) in DON3 and DON5 compared with DON1-fed pigs. Nitrogen retention efficiency was higher (P < 0.05) in DON1 compared with DON3 and DON5 and protein deposition for DON1 pigs was higher (P < 0.05) than all treatments. There were no treatment effects on indicators of liver and kidney health. As dietary DON intake increased, concentration of DON in blood and urine increased. Overall, although there was an initial decrease in ADG and ADFI in pigs receiving diets containing >1 ppm DON, pig performance recovered after a period of time, whereas nutrient utilization continued to be affected after recovery of performance. Moreover, the lack of DON on G:F indicates that the negative effects of DON on growth performance are largely due to reduced feed intake. Overall, although pigs maybe capable of adapting to intake of DON-contaminated diets, their final body weight will be reduced when fed diets containing >1 ppm DON.

Functional amino acid supplementation, regardless of dietary protein content, improves growth performance and immune status of weaned pigs challenged with Salmonella Typhimurium

High dietary protein may increase susceptibility of weaned pigs to enteric pathogens. Dietary supplementation with functional amino acids (FAA) may improve growth performance of pigs during disease challenge. The objective of this study was to evaluate the interactive effects of dietary protein content and FAA supplementation above requirements for growth on performance and immune response of weaned pigs challenged with Salmonella. Sixty-four mixed-sex weanling pigs (13.9 ± 0.82 kg) were randomly assigned to dietary treatments in a 2 × 2 factorial arrangement with low (LP) or high protein (HP) content and basal (AA-) or FAA profile (AA+; Thr, Met, and Trp at 120% of requirements) as factors. After a 7-d adaptation period, pigs were inoculated with either a sterile saline solution (CT) or saline solution containing Salmonella Typhimurium (ST; 3.3 × 109 CFU/mL). Growth performance, body temperature, fecal score, acute-phase proteins, oxidant/antioxidant balance, ST shedding score in feces and intestinal colonization, fecal and digesta myeloperoxidase (MPO), and plasma urea nitrogen (PUN) were measured pre- and postinoculation. There were no dietary effects on any measures pre-inoculation or post-CT inoculation (P > 0.05). Inoculation with ST increased body temperature and fecal score (P < 0.05), serum haptoglobin, plasma superoxide dismutase (SOD), malondialdehyde (MDA), PUN, and fecal MPO, and decreased serum albumin and plasma reduced glutathione (GSH):oxidized glutathione (GSSG) compared with CT pigs (P < 0.05). ST-inoculation reduced average daily gain (ADG) and feed intake (ADFI) vs. CT pigs (P < 0.05) but was increased by AA+ vs. AA- in ST pigs (P < 0.05). Serum albumin and GSH:GSSG were increased while haptoglobin and SOD were decreased in ST-inoculated pigs fed AA+ vs. AA- (P < 0.05). PUN was higher in HP vs. LP-fed pigs postinoculation (P < 0.05). Fecal ST score was increased in ST-inoculated pigs on days 1 and 2 postinoculation and declined by day 6 (P < 0.05) in all pigs while the overall score was reduced in AA+ vs. AA- pigs (P < 0.05). Cecal digesta ST score was higher in HP vs. LP-fed pigs and were lower in AA+ compared with AA- fed pigs in the colon (P < 0.05). Fecal and digesta MPO were reduced in ST pigs fed AA+ vs. AA- (P < 0.05). These results demonstrate a positive effect of FAA supplementation, with minimal effects of dietary protein, on performance and immune status in weaned pigs challenged with Salmonella.

118 Functional amino acid supplementation, regardless of dietary protein content, improves growth performance, acute-phase response, and bacterial shedding in Salmonella-challenged pigs

The present study investigated the interactive effect of functional amino acid (AA) supplementation and dietary protein level on growth performance and immune status in Salmonella-challenged pigs. Thirty-two growing pigs (8 pigs/treatment; 13.9 ± 0.82 kg initial body weight) had ad libitum access to 1 of 4 experiment diets in a 2×2 factorial arrangement with factors of dietary protein (LP: Low, 16% protein vs. High: HP, 20% protein) and 2 levels of functional AA supply (AA-: basal vs. AA+: Thr, Met, and Trp provided at 20% above requirement). After 7 d of adaptation, pigs were orally inoculated with saline containing Salmonella typhimurium (ST). Performance parameters [average daily gain (ADG), feed intake, and gain:feed (GF)] were measured in the pre- and post-inoculation periods. Blood samples were collected on d0, 4 and 7 post-inoculation for serum haptoglobin and albumin analysis. Shedding of ST (d1, 2, 4 and 6 post-inoculation) and quantification in digesta (ileum, cecum and colon; d7 post-inoculation) were analyzed. There was no effect of diet on pre-inoculation performance (P &gt; 0.05). Pigs fed AA+ showed increased ADG (0.457 vs. 0.298 ± 0.051 kg/d; P &lt; 0.05) and a trend for improved GF (0.67 vs. 0.40 ± 0.07 kg/kg; P &lt; 0.10) post-inoculation compared to AA- regardless of dietary protein level. Feeding AA+ increased overall albumin levels (35.7 vs. 34.2 ± 0.9 g/L; P &lt; 0.05) and decreased overall haptoglobin levels (1.64 vs. 1.81 ± 0.12 g/L; P &lt; 0.05) and decreased overall shedding score of ST (2.27 vs. 2.51 ± 0.09; P &lt; 0.05) compared to AA-. The ST counts in cecal digesta increased (2.78 vs. 2.23 ± 0.18 Log10 cfu/g; P &lt; 0.05) in pigs fed HP compared to LP-fed pigs and ST counts in colon were reduced (2.08 ± 0.18 vs. 2.61 ± 0.19 Log10 cfu/g; P &lt; 0.05) in AA+ compared to AA- pigs. Supplementation of diets with specific functional AA improved performance and health status of pigs when exposed to an enteric disease challenge.

Characterization of a Swine Model of Birth Weight and Neonatal Nutrient Restriction

Background

Evidence indicates that birth weight and neonatal nutrition have lifelong effects. Animal models are required to improve our understanding of these factors.

Objectives

We aimed to develop and validate a swine model of birth weight and neonatal undernutrition.

Methods

At birth, a total of 112 piglets were identified as low (LBW; 1.22 ± 0.28 kg SEM) or normal birth weight (NBW; 1.70 ± 0.27 kg). From day 3 to weaning (day 28), piglets received normal nutrition (NN) or restricted nutrition (RN) via intermittent suckling, where piglets were isolated from the sow for 6 h/d. After weaning, pigs were fed a common diet for 28 d. Body weight (BW) was determined for the duration of the study. On days 28 and 56, empty carcass, viscera, and individual organ weights were determined in 8 pigs/treatment.

Results

LBW pigs remained smaller than NBW pigs, regardless of nutrient restriction (P &lt; 0.05). Within birth weight category, RN reduced BW by day 7 after birth, which was maintained until weaning (P &lt; 0.05); however, at 7 d postweaning there was no difference in BW due to RN (P &gt; 0.05). At weaning, empty carcass, viscera, heart, liver, and lung weights were lower in LBW than in NBW pigs, whereas empty carcass, heart, small intestine, liver, kidneys, lung, and spleen weights were lower in RN than in NN pigs (P &lt; 0.05). Brain weight was highest in NBW-NN and lowest in NBW-RN, with LBW intermediate, regardless of nutrient restriction (P &lt; 0.05). Postweaning, LBW had lower empty carcass, viscera, heart, stomach, large intestine, liver, and kidney weights than NBW, whereas RN had a higher small intestine weight than NN (P &lt; 0.05).

Conclusions

Intermittent suckling is an effective means of inducing nutrient restriction in a swine model.

Effect of dietary fiber and threonine content on intestinal barrier function in pigs challenged with either systemic E. coli lipopolysaccharide or enteric Salmonella Typhimurium

Background

The independent and interactive effects of dietary fiber (DF) and threonine (Thr) were investigated in growing pigs challenged with either systemic E. coli lipopolysaccharide (LPS) or enteric Salmonella Typhimurium (ST) to characterise their effect on intestinal barrier function.

Results

In experiment 1, intestinal barrier function was assessed via oral lactulose and mannitol (L:M) gavage and fecal mucin analysis in pigs challenged with E. coli LPS and fed low fiber (LF) or high fiber (HF) diets with graded dietary Thr. Urinary lactulose recovery and L:M ratio increased (P < 0.05) during the LPS inoculation period in LF fed pigs but not in HF fed pigs. Fecal mucin output was increased (P < 0.05) in pigs fed HF compared to LF fed pigs. In experiment 2, RT-qPCR, ileal morphology, digesta volatile fatty acid (VFA) content, and fecal mucin output were measured in Salmonella Typhimurium challenged pigs, fed LF or HF diets with standard or supplemented dietary Thr. Salmonella inoculation increased (P < 0.05) fecal mucin output compared to the unchallenged period. Supplemental Thr increased fecal mucin output in the HF-fed pigs (Fib × Thr; P < 0.05). Feeding HF increased (P < 0.05) VFA concentration in cecum and colon. No effect of either Thr or fiber on expression of gene markers was observed except a tendency (P = 0.06) for increased MUC2 expression with the HF diet. Feeding HF increased goblet cell numbers (P < 0.05).

Conclusion

Dietary fiber appears to improve barrier function through increased mucin production capacity (i.e., goblet cell numbers, MUC2 gene expression) and secretion (i.e., fecal mucin output). The lack of effect of dietary Thr in Salmonella-challenged pigs provides further evidence that mucin secretion in the gut is conserved and, therefore, Thr may be limiting for growth under conditions of increased mucin production.

Effect of supplemental threonine above requirement on growth performance of Salmonella typhimurium challenged pigs fed high-fiber diets1

It was shown previously that high dietary fiber (DF) and immune system stimulation (ISS) with systemic Escherichia coli lipopolysaccharide independently increased the threonine (Thr) requirement to maximize growth performance and protein deposition (PD). However, no additive effects on the Thr requirement were observed when both DF and ISS were present. The objective of the present study was to investigate whether supplementing Thr to meet previously estimated requirements for high DF and systemic immune challenge would maintain performance of pigs exposed to an enteric immune challenge when fed high DF. A total of 128 pigs (22.6 ± SD = 1.6 kg initial BW) were assigned to 1 of 4 dietary treatments in a 2 × 2 factorial arrangement in a randomized complete block design (n = 8 pens/treatment and 4 pigs/pen) for 28 d. Treatments were a low-fiber (LF; 13% total DF) or high-fiber (HF; 20% total DF) diet with either a standard (STD; 0.65% SID) or supplemental (SUP; 0.78% SID) Thr level. After a 7-d adaptation, pigs were orally inoculated with 2 mL (2.3 × 109 CFU/mL) of Salmonella typhimurium (ST). Blood samples and rectal swabs were obtained and rectal temperature recorded to determine clinical responses and ST shedding. On day 7 postinoculation, 1 pig/pen was euthanized and mesenteric lymph nodes, spleen, and digesta (ileum, cecum, and colon) were sampled to assess ST colonization and translocation. Body weight and feed intake were recorded on day 0, 7, and 21 postinoculation to calculate ADG, ADFI, and G:F. Rectal temperature increased (P < 0.05) 24 h postinoculation and remained elevated at day 6. Serum albumin concentration decreased (P < 0.05), whereas haptoglobin concentration increased (P < 0.05) postinoculation. There was no fiber or Thr effect (P > 0.05) on ST counts in the ileum and cecum, but a fiber × Thr interaction (P < 0.05) was observed in the colon. Supplemental Thr improved (P < 0.05) growth performance in LF- and HF-fed challenged pigs. However, performance of supplemented HF challenged pigs was less than (P < 0.05) supplemented LF challenged pigs. These results suggest that Thr supplemented to meet requirements for high DF and systemic immune challenge was not sufficient to maintain growth performance of pigs fed HF diets and challenged with an enteric pathogen.

Impact of dietary fiber and immune system stimulation on threonine requirement for protein deposition in growing pigs

High dietary fiber (DF) and immune system stimulation (ISS) are thought to limit amino acid availability for protein deposition (PD) in growing pigs. A nitrogen-balance study was conducted to determine Thr requirement for optimal PD when DF and ISS were present alone and in combination. A total of 90 barrows (20.5 kg initial BW; SD = 0.75 kg) were randomly assigned to one of 10 dietary treatments (n = 9) in nine blocks. Diets consisted of a low fiber (LF; 12.5% total DF) or high fiber (HF; 18.5% total DF by adding 10% sugar beet pulp and 5% wheat bran to the LF diet) with graded levels of Thr (0.49%, 0.57%, 0.65%, 0.73%, and 0.81% standardized ileal digestible [SID]) fed at 2.2 × maintenance ME requirements. After an 8-d adaptation, two 4-d nitrogen balance collection periods (pre-ISS and ISS) were conducted. ISS was induced by repeated injections (i.m.) of increasing doses of Escherichia coli lipopolysaccharide. Blood samples were taken during both periods to assess acute phase proteins and complete blood cell count. Data were analyzed by PROC MIXED with fixed effects of period, Thr, fiber, and their interactions, with block as a random effect. Nitrogen balance was analyzed separately for each period. Threonine requirement was estimated using PROC NLIN quadratic break-point model. Serum concentration of albumin, haptoglobin, fibrinogen, whole blood white blood cell, and platelet count were affected by ISS (P < 0.001) confirming successful ISS. During pre-ISS, PD increased linearly (P < 0.01) as Thr concentration in the diet increased, with a significant interaction (P < 0.05) between fiber and Thr. During ISS, PD increased linearly (P < 0.05) as Thr concentration in the diet increased. Quadratic break-point model estimated SID Thr required to maximize PD of pigs fed LF and HF diets during pre-ISS period was 0.68% (R2 = 0.88) and 0.78% (R2 = 0.99), respectively. During ISS, the SID Thr requirement was estimated at 0.76% (R2 = 0.76) for LF diet and 0.72% (R2 = 0.95) for HF fed pigs. HF and ISS independently increased Thr requirement for maximum PD, but these effects were not additive. HF may therefore mask the effects of ISS on Thr requirement for immune response and PD.