C. J. O'Shea

Effect of β-glucans contained in barley- and oat-based diets and exogenous enzyme supplementation on gastrointestinal fermentation of finisher pigs and subsequent manure odor and ammonia emissions.

The objective of the current experiment was to evaluate the influence of dietary cereal sources of beta(1,3)(1,4)-d-glucan (beta-glucan) and enzyme supplementation on indices of environmental pollution from finisher pigs. An experiment with a 2 x 2 factorial arrangement of treatments was initiated to investigate the effect of dietary source of beta-glucan (barley vs. oats) and enzyme supplementation (no vs. yes) on nutrient digestibility, N utilization, intestinal fermentation, and manure odor and ammonia emissions from finisher boars (n = 4; BW = 73.9 kg; SD = 4.7). Sixteen boars were assigned to 1 of 4 dietary treatments (n = 4/treatment): 1) barley-based diet, 2) barley-based diet + exogenous enzyme, 3) oat-based diet, and 4) oat-based diet + enzyme. The enzyme supplement used contained endo-1,3(4)-beta-glucanase and endo-1,4-beta-xylanase. Experimental diets were formulated to contain similar concentrations of DE (13.5 MJ/kg) and digestible lysine (8.8 g/kg). Pigs offered oat-based diets had reduced digestibility of DM (0.795 vs. 0.849; SEM 0.007; P = 0.001), OM (0.808 vs. 0.865; SEM 0.007; P = 0.001), GE (0.806 vs. 0.845; SEM 0.006; P = 0.002), and NDF (0.233 vs. 0.423; SEM 0.033; P < 0.003) compared with those offered barley-based diets. Oat-based diets increased populations of Bifidobacterium spp. (7.26 vs. 6.38 log cfu/g of digesta; SEM 0.201; P = 0.005) and Lactobacillus spp. (6.99 vs. 6.18 log cfu/g of digesta; SEM 0.234; P = 0.022) in the proximal colon and decreased manure odor emissions [2,179.6 vs. 4,984.6 Ou(E)/m(3) (where Ou(E) refers to European odor units); SEM 653.7; P < 0.011] compared with barley-based diets. There was an interaction between cereal type and enzyme inclusion on manure ammonia emissions from 0 to 96 h (P = 0.050). Pigs offered barley-based diets containing an enzyme supplement had increased manure ammonia emissions compared with those offered unsupplemented barley-based diets. However, there was no effect of enzyme inclusion on oat-based diets. In conclusion, pigs offered oat-based diets harbored increased Bifidobacterium spp. and Lactobacillus spp. populations in the proximal colon and had decreased manure odor emissions compared with those offered barley-based diets. Enzyme inclusion had no effect on manure ammonia emissions from pigs offered oat-based diets.

Effect of dietary laminarin and fucoidan on selected microbiota, intestinal morphology and immune status of the newly weaned pig

A 2 × 2 factorial experiment was conducted to investigate the interactions between laminarin (LAM; 0 and 300 parts per million (ppm)) and fucoidan (FUC; 0 and 240 ppm) levels on intestinal morphology, selected microbiota and inflammatory cytokine gene expression in the weaned pig. There was an interaction between LAM and FUC supplementation on the Enterobacteriaceae population (P< 0·05) and the abundance of attaching and effacing Escherichia coli (AEEC) strains (P< 0·05) in the colon. Pigs offered the FUC diet had a reduced Enterobacteriaceae population compared with pigs offered the basal diet. However, the effect of FUC on the Enterobacteriaceae population was not observed when combined with LAM. Pigs offered the LAM diet had reduced abundance of AEEC strains compared with pigs offered the basal diet. However, there was no effect of LAM on the abundance of AEEC strains when combined with FUC. There was an interaction between LAM and FUC supplementation on villous height (P< 0·01) and the villous height:crypt depth ratio (P< 0·01) in the duodenum. Pigs offered the LAM or FUC diet had an increased villous height and villous height:crypt depth ratio compared with pigs offered the basal diet. However, there was no effect of the LAM and FUC combination diet on intestinal morphology. Pigs offered the LAM-supplemented diets had a lower IL-6 (P< 0·05), IL-17A (P< 0·01) and IL-1β (P< 0·01) mRNA expression in the colon compared with pigs offered the diets without LAM. In conclusion, supplementation with either LAM or FUC alone modified intestinal morphology and selected intestinal microbiota, but these effects were lost when offered in combination.

Indices of gastrointestinal fermentation and manure emissions of growing-finishing pigs as influenced through singular or combined consumption of Lactobacillus plantarum and inulin.

Conventional dietary strategies to reduce pig manure odor may either be costly, or impede nutrient digestibility. Additionally, the response of manure odor to such measures may be variable, indicating a complex relationship between environmental pollutant and diet. We hypothesized that dietary Lactobacillus plantarum (LP), with or without the inclusion of a purified oligofructose (inulin), may reduce odor without compromising nutrient digestibility. An experiment with a 2 × 2 factorial arrangement of treatments was conducted to investigate effects of dietary inulin (0 and 12.5 g/kg) and LP (0 and 0.5 g/kg) on nutrient digestibility, indicators of gastrointestinal tract fermentation, select fecal bacteria, manure content, and ammonia and odor emissions of 28 growing-finishing pigs (60.3 kg; n = 7/treatment). Dietary treatments had no effect on nutrient digestibility. Dietary treatments containing inulin had decreased Enterobacteriaceae (8.60 vs. 9.67 log gene copy number/g fresh feces; P = 0.03) when compared with unsupplemented diets. There was an interaction between dietary inulin concentration and LP supplementation on estimates of fecal Clostridia (P = 0.01). Pigs offered diets containing both inulin and LP in combination had increased Clostridia when compared with those offered the control diet. However, there was no effect of either LP or inulin fecal Clostridia when offered singularly. An interaction was also noted where diets supplemented with LP or inulin only reduced odor (P = 0.01) compared with the control diet. However, there was no effect of LP on manure odor emissions when offered in combination with inulin. In summary, this study demonstrated that dietary supplementation with either exogenous LP or inulin reduces manure odor but not when offered in combination.

Influence of incrementally substituting dietary soya bean meal for rapeseed meal on nutrient digestibility, nitrogen excretion, growth performance and ammonia emissions from growing-finishing pigs

A completely randomised design experiment was performed to examine the effects of replacing different levels of soya bean meal (SBM) with rapeseed meal (RSM) on the growth performance, carcass characteristics, apparent nutrient digestibility, nitrogen (N) balance and manure ammonia emissions of growing-finishing pigs. Pigs (n = 336; mean live weight 42.1 kg) were assigned to one of four dietary treatments containing per kg diet: 210 g SBM; 140 g SBM and 70 g RSM; 70 g SBM and 140 g RSM; and 210 g RSM. All diets were formulated on an ileal digestible amino acid, net energy and available phosphorus basis. There was no significant treatment effect on average daily gain, feed intake, feed conversion ratio and carcass characteristics. There was a linear decrease in gross energy digestibility (p < 0.01) as RSM increased at the expense of SBM in the diet. There was a linear decrease in urinary N excretion (p < 0.01), N digestibility (p < 0.05), total N excretion (p < 0.05) and N retention (p < 0.05) with increasing levels of RSM. There was no effect of dietary treatment on manure ammonia emissions. The results of this study indicate that RSM can be used as a direct replacement for SBM with no associated depression in performance, when formulated on an ileal digestible amino acid and net energy basis. Consumption of diets containing incremental levels of RSM linearly decreased urinary N and total N excretion, reflecting the associated decrease in crude protein concentrations.

Effect of the interaction of seaweed extracts containing laminarin and fucoidan with zinc oxide on the growth performance, digestibility and faecal characteristics of growing piglets

Seaweed extracts (SWE) rich in laminarin and fucoidan have shown promise as a supplement for weaned piglets. However, successful application in pig nutrition depends on their bioactivity in the presence of additives such as ZnO. In the present study, a 2 × 2 factorial experiment was carried out to investigate the effect of the interaction between SWE and ZnO on the growth performance, digestibility and faecal characteristics of 192 weaned piglets (6·5 kg). The piglets were penned in groups of 4 (n 12 pens). The study consisted of two phases after weaning: a starter diet period from the day of weaning (0 d) to 21 d and a transition diet period from 21 to 40 d. The dietary treatments were as follows: (1) control diet; (2) control diet+ZnO; (3) control diet+SWE; (4) control diet+ZnO+SWE. Diets containing ZnO improved the faecal consistency of the piglets throughout the experimental period (0-40 d). An effect of the interaction between ZnO and SWE on several variable was observed. The diet containing only SWE or ZnO improved the feed conversion efficiency of the piglets during the transition diet period; however, this effect was not observed when the diet containing both ZnO and SWE was fed. The diet containing only SWE increased the N and organic matter digestibility of the piglets; however, this effect was not observed in the presence of ZnO. An interaction between ZnO and SWE was observed, whereby the faecal counts of Escherichia coli were decreased when piglets were fed the diet containing only SWE, but not when fed the diet containing both SWE and ZnO. In summary, SWE and ZnO improve growth performance when given alone, but not when given in combination. The biological effect of SWE on selected digestibility and faecal characteristics was markedly different when compared with that of ZnO.

Modification of selected bacteria and markers of protein fermentation in the distal gastrointestinal tract of pigs upon consumption of chitosan is accompanied by heightened manure odor emissions

Previous studies have indicated that reducing dietary CP may improve N utilization and effectively diminish manure ammonia emissions; however, the response of manure odor emissions to such dietary modifications has been inconsistent. The objective of the current experiment was to induce decreased lactobacilli (DL) numbers in the distal gastrointestinal tract (dGIT; cecum + colon) of finishing pigs offered both high- and low-CP diets through consumption of chitosan, and examine the influence of this model on manure ammonia and odor emissions when compared with a positive control diet. It was hypothesized that an DL population would be accompanied by an increase in markers of protein fermentation. When compared with normal lactobacilli populations in the dGIT, generation of an DL population would result in increased manure odor emissions from pigs offered both dietary CP concentrations. A 2 × 2 factorial arrangement of treatments was conducted to investigate the effect of including chitosan [0 (positive control) vs. 20 g/kg of feed] and high or low dietary CP concentration (200 vs. 150 g/kg of feed) on nutrient digestibility, N utilization, selected bacterial populations, and metabolite composition of the dGIT and manure emissions from finisher pigs (60.3 kg). Consumption of chitosan had no influence (P > 0.05) on nutrient digestibility or N utilization. In both high- and low-CP diets, consumption of chitosan decreased the lactobacilli-to-Enterobacteriaceae ratio (P < 0.01), generating an DL population, and increased pH (P < 0.01) in the dGIT and ammonia (P = 0.02) in the cecum compared with diets that supported normal lactobacilli populations. Consumption of chitosan decreased molar proportions of butyric acid (P < 0.01) and increased valeric acid (P < 0.01) in the dGIT compared with unsupplemented diets. Furthermore, consumption of chitosan increased manure odor emissions (P = 0.05) compared with unsupplemented diets. There was no effect (P > 0.05) of chitosan consumption on manure ammonia emissions from 0 to 240 h. The current study demonstrates that dietary chitosan suppressed populations of lactobacilli in the dGIT. In response, a considerable increase in Enterobacteriaceae, markers of protein fermentation, and manure odor emissions was observed compared with the positive control diet. These effects were observed in pigs offered both high-and low-CP diets. The current study indicates a possible role for lactic-acid bacteria in modulating manure odor emissions relatively independent of the proportions of dietary CP available for fermentation in the dGIT.

Effect of maternal supplementation with seaweed extracts on growth performance and aspects of gastrointestinal health of newly weaned piglets after challenge with enterotoxigenic Escherichia coli K88

In the present study, a 2 × 2 factorial arrangement was conducted to investigate the effect of maternal supplementation with seaweed extracts ( - SWE v. +SWE, n 20) from day 83 of gestation until weaning (day 28) on post-weaning (PW) growth performance, faecal score, faecal enterotoxigenic Escherichia coli (ETEC) toxin quantification, intestinal histology and cytokine mRNA of unchallenged and ETEC-challenged pigs. Pigs were ETEC challenged on day 9 PW. There was a maternal treatment × challenge (SWE × ETEC) interaction effect on growth performance and faecal score (P< 0.05). Pigs from SWE-supplemented sows and ETEC-challenged (SE) had higher average daily gain (ADG) during 0-13 d PW and reduced faecal score during 0-72 h post-challenge than those from basal-fed sows and ETEC-challenged (BE) (P< 0.05). However, there was no difference between unchallenged pigs from the SWE-supplemented sows (SC) and basal-fed sows (BC) (P>0.10). Pigs from the SWE-supplemented sows had reduced heat-labile enterotoxin gene copy numbers than those from the basal-fed sows (P< 0.05). Maternal SWE supplementation increased the villus height in the ileum of pigs (P< 0.05). There was a SWE × ETEC interaction effect (P< 0.05) on IL-6 mRNA and a SWE × gastrointestinal (GI) region interaction effect (P< 0.05) on transforming growth factor-β1 (TGF-β1) and TNF-α mRNA. IL-6 mRNA was down-regulated in SC pigs than BC pigs (P< 0.05). However, there was no difference in IL-6 mRNA between SE and BE pigs. The mRNA of TGF-β1 and TNF-α was down-regulated in the colon of pigs from the SWE-supplemented sows compared with those from the basal-fed sows (P< 0.05). However, there was no difference in TGF-β1 and TNF-α mRNA in the ileum between the pigs from the SWE-supplemented sows and basal-fed sows. In conclusion, maternal SWE supplementation improves ADG and the aspects of GI health of weaned pigs following an ETEC challenge.

Pigs that are divergent in feed efficiency, differ in intestinal enzyme and nutrient transporter gene expression, nutrient digestibility and microbial activity.

Feed efficiency is an important trait in the future sustainability of pig production, however, the mechanisms involved are not fully elucidated. The objective of this study was to examine nutrient digestibility, organ weights, select bacterial populations, volatile fatty acids (VFAs), enzyme and intestinal nutrient transporter gene expression in a pig population divergent in feed efficiency. Male pigs (n=75; initial BW 22.4 kg SEM 2.03 kg) were fed a standard finishing diet for 43 days before slaughter to evaluate feed intake and growth for the purpose of calculating residual feed intake (RFI). Phenotypic RFI was calculated as the residuals from a regression model regressing average daily feed intake (ADFI) on average daily gain (ADG) and midtest BW0.60 (MBW). On day 115, 16 pigs (85 kg SEM 2.8 kg), designated as high RFI (HRFI) and low RFI (LRFI) were slaughtered and digesta was collected to calculate the coefficient of apparent ileal digestibility (CAID), total tract nutrient digestibility (CATTD), microbial populations and VFAs. Intestinal tissue was collected to examine intestinal nutrient transporter and enzyme gene expression. The LRFI pigs had lower ADFI (P<0.001), improved feed conversion ratio (P<0.001) and an improved RFI value relative to HRFI pigs (0.19 v. -0.14 SEM 0.08; P<0.001). The LRFI pigs had an increased CAID of gross energy (GE), and an improved CATTD of GE, nitrogen and dry matter compared to HRFI pigs (P<0.05). The LRFI pigs had higher relative gene expression levels of fatty acid binding transporter 2 (FABP2) (P<0.01), the sodium/glucose co-transporter 1 (SGLT1) (P<0.05), the glucose transporter GLUT2 (P<0.10), and the enzyme sucrase-isomaltase (SI) (P<0.05) in the jejunum. The LRFI pigs had increased populations of lactobacillus spp. in the caecum compared with HRFI pigs. In colonic digesta HRFI pigs had increased acetic acid concentrations (P<0.05). Differences in nutrient digestibility, intestinal microbial populations and gene expression levels of intestinal nutrient transporters could contribute to the biological processes responsible for feed efficiency in pigs.

Improvements in growth performance, bone mineral status and nutrient digestibility in pigs following the dietary inclusion of phytase are accompanied by modifications in intestinal nutrient transporter gene expression

Phytase (PHY) improves growth performance, nutrient digestibility and bone structure in pigs; however, little is known about its effects on intestinal nutrient transporter gene expression. In the present study, a 44 d experiment was carried out using forty-eight pigs (11·76 (sem 0·75) kg) assigned to one of three dietary treatment groups to measure growth performance, coefficient of apparent ileal digestibility (CAID), coefficient of apparent total tract nutrient digestibility (CATTD) and intestinal nutrient transporter gene expression. Dietary treatments during the experimental period were as follows: (1) a high-P (HP) diet containing 3·4 g/kg available P and 7·0 g/kg Ca; (2) a low-P (LP) diet containing 1·9 g/kg available P and 5·9 g/kg Ca; (3) a PHY diet containing LP diet ingredients+1000 phytase units (FTU)/kg of PHY. The PHY diet increased the average daily gain (P< 0·05) and final body weight (P< 0·01) and decreased the feed conversion ratio (P< 0·05) compared with the LP diet. Pigs fed the PHY diet had a higher CAID of gross energy compared with those fed the HP and LP diets (P< 0·001). Pigs fed the PHY diet had increased CAID of P (P< 0·01) and CATTD of Ca and P (P< 0·001) compared with those fed the LP diet. The PHY diet increased the gene expression of the peptide transporter 1 (PEPT1/SLC15A1) (P< 0·05) in the ileum compared with the LP diet. The LP diet decreased the gene expression of the sodium-glucose-linked transporter 1 (SGLT1/SLC5A1) and GLUT2/SLC2A2 (P< 0·05) and increased the expression of membrane Ca channel (TRPV6) and calbindin compared with the HP diet (P< 0·001). In conclusion, feeding a diet supplemented with PHY improves growth performance and nutrient digestibility as well as increases the gene expression of the peptide transporter PEPT1.

The effect of algal polysaccharides laminarin and fucoidan on colonic pathology, cytokine gene expression and Enterobacteriaceae in a dextran sodium sulfate-challenged porcine model

The algal polysaccharides laminarin (LAM) and fucoidan (FUC) have potent anti-inflammatory activities in the gastrointestinal tract. Our objective was to examine the impact of prior consumption of LAM and/or FUC on pathology and inflammation following a dextran sodium sulfate (DSS) challenge in pigs. Pigs (n 7/group) were assigned to one of five experimental groups for 56 d. From 49–55 d, distilled water or DSS was administered intragastrically. The experimental groups were: (1) basal diet + distilled water (control); (2) basal diet + DSS (DSS); (3) basal diet + FUC + DSS (FUC + DSS); (4) basal diet + LAM + DSS (LAM + DSS); and (5) basal diet + LAM + FUC + DSS (LAMFUC + DSS). The DSS group had decreased body-weight gain (P < 0·05) and serum xylose (P < 0·05), and increased proximal colon pathology score (P < 0·05), diarrhoeal score (P < 0·001) and colonic Enterobacteriaceae (P < 0·05) relative to the control group. The FUC + DSS (P < 0·01), LAM + DSS (P < 0·05) and LAMFUC + DSS (P < 0·05) groups had improved diarrhoeal score, and the LAMFUC + DSS (P < 0·05) group had improved body weight relative to the DSS group. The FUC + DSS group (P < 0·001), LAM + DSS group (P < 0·05) and LAMFUC + DSS group (P < 0·001) had lower IL-6 mRNA abundance relative to the DSS group. The LAM + DSS group had reduced Enterobacteriaceae in proximal colon digesta relative to the DSS group (P < 0·05). In conclusion, FUC or a combination of FUC and LAM improved body-weight loss, diarrhoeal scores and clinical variables associated with a DSS challenge in pigs, in tandem with a reduction in colonic IL-6 mRNA abundance.