Growth performance, organs weight, intestinal histomorphology, and oocyst shedding in broiler chickens offered novel single strain Bacillus subtilis isolated from camel dung and challenged with Eimeria.

We evaluated a single strain Bacillus subtilis BS-9 direct-fed microbial (BSDFM) isolated from camel dung in Eimeria challenged broiler chickens. Seven-hundred d-old Ross 708 male chicks were placed in pens (25 birds/pen) and allocated to 2 treatments (n = 14). From d 0 to 13, control pens received untreated water (-BSDFM), and 2 treated pens received water and 2 mL x 108 colony forming unit/bird/d (+BSDFM); daily water intake (WI) was recorded. On d 9, birds in half (+Eimeria) of pens per treatment received of 1 mL of Eimeria maxima and Eimeria acervulina oocysts orally, and the other half (-Eimeria) sterile saline solution. Birds had ad libitum access to feed and a water line from d 14. Feed intake (FI), body weight (BW) and mortality were recorded for calculating BW gain (BWG) and feed conversion ratio (FCR). On d 14 and 35, samples of birds were necropsied for organ weight and intestinal measurements. Excreta samples were collected from d 14 to 19 for oocyst count. There was no treatment effect (P > 0.05) on growth performance or WI on d 0 to 9. There were interactions between BSDFM and Eimeria on d 19 (P = 0.014) and 29 (P = 0.036) BW with unchallenged +BSDFM birds being heavier than birds in the other treatments. The main effects (P < 0.05) on d 10 to 35 FI, BW, and BWG were such that +BSDFM increased and Eimeria decreased (P < 0.01) these parameters. There was interaction (P = 0.022) between BSDFM and Eimeria on d 10 to 35 FCR such that the FCR of challenged -BSDFM birds was poor than that of unchallenged counterparts, but none differed with +BSDFM birds. There was an interaction (P = 0.039) between BSDFM and Eimeria on d 14 bursa weight with challenged birds exhibiting heavier bursa than unchallenged +BSDFM birds. Eimeria reduced (P = 0.01) and BSDFM (P = 0.002) increased the villi height to crypt depth ratio. Results showed that BSDFM supplementation via water can support the growth performance of broiler chickens challenged with Eimeria and may be a strategy to reduce adverse effects of coccidiosis.

Evaluation of multienzyme supplementation and fiber levels on nutrient and energy digestibility of diets fed to gestating sows and growing pigs.

The objective was to investigate the effect of a multienzyme blend (MEblend) and inclusion level on apparent total tract digestibility (ATTD) of energy and nutrients, as well as ileal digestibility of crude protein (CP) and amino acids (AA) in gestation diets with low (LF) or high-dietary fiber (HF) fed to gestation sows. For comparison, growing pigs were fed the same HF diets to directly compare ATTD values with the gestating sows. In experiment 1, 45 gestating sows (parity 0 to 5; 187 ±â€…28 kg bodyweight; BW) were blocked by parity in a 2 × 3 factorial arrangement and fed 2.2 kg/d of the HF (17.5% neutral detergent fiber; NDF) or LF (13% NDF) diet and one of three levels of MEblend (0.0%, 0.08%, and 0.1%) to determine impacts of MEblend on ATTD. Twenty-seven growing pigs (initial 35.7 ±â€…3.32 kg BW) were fed the same HF diet (5% of BW) and one of three MEblend inclusions. The MEblend at both 0.08% and 0.1% increased ATTD of energy, NDF, and acid detergent fiber (ADF) (P < 0.05) in gestating sows but ATTD of total non-starch polysaccharides (NSP) and its residues were not affected. Sows fed HF, regardless of MEblend, had greater ATTD of NDF, xylose, and total NSP (P < 0.05) in comparison to grower pigs. In experiment 2, ileal cannulas were placed in 12 gestating sows (parity 0 to 2; BW 159 ±â€…12 kg) to determine apparent and standardized ileal digestibility (AID and SID) of AA and NSP. In a crossover design, sows were fed the same six diets, as in experiment 1, and a nitrogen-free diet during five periods of seven days each to achieve eight replicates per diet. There was no interaction between diet fiber level and MEblend inclusion. Supplementation of MEblend to gestating sow diets did not impact SID of CP and AA regardless of dietary fiber level. The SID of His, Ile, Lys, Phe, Thr, Trp, and Val were 3% to 6% lower (P < 0.09) in HF than LF independent of MEblend. Supplementation of MEblend did not impact AID of NSP components, but sows fed HF had higher AID of arabinose (LF: 26.5% vs. HF: 40.6%), xylose (LF: 3.5% vs. HF: 40.9%), and total NSP (LF: 25.9% vs. HF: 40.0%) compared to sows fed LF (P < 0.05). Dietary supplementation of MEblend increased ATTD of nutrients, NSP, and energy in diets fed to gestating sows regardless of inclusion level, with MEblend having a greater incremental increase in diets with lower NDF levels. Inclusion of MEblend impacted neither SID of AA nor AID of NSP in low- or high-fiber gestation diets, but high-fiber diet, negatively affected SID of AA.

Fiber-degrading enzymes have been extensively studied in growing pigs with minimal studies focusing on gestating sows; however, commercial gestating sow diets often contain more fiber than grower pig diets to stimulate the sensation of satiety without influencing weight gain. A challenge with dietary fiber is its hindrance on digestibility of nutrients. Supplementation of multienzyme blends increases nutrient digestibility of fibrous diets in grower pigs, but there is little data characterizing the effects of fiber-degrading enzymes in gestation diets for pregnant sows. In this study, inclusion of a multienzyme comprised of various carbohydrases and a protease in gestation diets increased apparent total tract digestibility of nutrients and energy for both gestating sows and growing pigs; however, digestibility of non-starch polysaccharides was only improved in growing pigs. Enzyme supplementation to gestating sow diets had limited impact on the ileal digestibility of nutrients, but ileal digestibility of amino acids and crude protein was reduced when gestating sows were fed diets higher in neutral detergent fiber. When formulating high-fiber diets for gestating sows and growing pigs using similar ingredients, it is critical to consider the differences in digestibility of fibrous components, particularly regarding ileal digestibility of amino acids.

Comparative growth performance, gizzard weight, ceca digesta short chain fatty acids and nutrient utilization in broiler chickens and turkey poults in response to cereal grain type, fiber level, and multienzyme supplement fed from hatch to 28 days of life.

Growth performance, gizzard weight, ceca digesta short-chain fatty acids (SCFA), and apparent retention (AR) of components were investigated in broilers and turkeys in response to cereal grain type, fiber level, and multienzyme supplement (MES) fed from hatch to 28 d of life. 480-day-old male broiler chicks and equal number of turkeys were placed separately in metabolism cages (10 birds/cage) and allocated to 8 diets. The species-specific diets were a corn or wheat-based basal diet without (LF) or with 10% corn DDGS or wheat middlings (HF) and fed without or with MES. This effectively created a 2 (grain types) × 2 (fiber levels) × 2 (MES) factorial arrangement of treatments. The diets had TiO2 as an indigestible marker. Body weight, feed intake, and mortalities were recorded to calculate body weight gain (BWG) and feed conversion ratio (FCR). Excreta samples were collected on d 25 to 27 for AR, and all birds were necropsied for gizzard weight and ceca digesta on d 28. The interaction between grain and MES in broilers was such that wheat diets with MES had the lowest (P = 0.005) FCR. In broilers, LF diets had better (P = 0.010) FCR than HF diets. The wheat diets had the highest (P = 0.006) concentration of butyric acid in broilers. Broilers fed HF and corn diets had heavier gizzard than broilers-fed LF and wheat diets. The MES improved (P < 0.05) AMEn in HF, corn, and wheat diets in broilers. The turkeys fed wheat diets had the lowest (P = 0.019) FCR. Turkeys fed HF wheat diets had the heaviest (P < 0.001) gizzard. In turkeys, the MES improved AMEn in HF and LF corn diets, and only in LF wheat diets compared to respective controls. Treatments had no effect on turkeys cecal SCFA. In conclusion, grain type, fiber, and MES did not affect growth in both species. However, species exhibited differing FCR, gizzard, and energy utilization to fiber and MES.

Enhancing the nutritive value of canola meal for broiler chickens through enzymatic modifications.

Enzymatic modification of canola meal (CM) is a potential method to enhance its nutritional value as it can depolymerize nonstarch polysaccharides (NSP) and mitigate its potential antinutritive properties. Based on the previous studies, pectinase A (PA), pectinase B (PB), xylanase B (XB), and invertase (Inv) were used for the enzymatic modifications. The highest NSP depolymerization ratio was obtained when 4 g/kg of each PA, PB, and XB, and 0.2 g/kg of Inv were used during 48 h incubation at 40 °C. In the current study, changes in pH, simple sugars, sucrose, oligosaccharides, and NSP contents during the enzymatic modification (CM+E) of CM were measured and compared to Control (CM) without enzymes addition or with the addition of bacteriostat sodium azide (CM+E+NaN3). The results showed that spontaneous fermentation occurred during incubation. After incubation, the pH of the slurry decreased, lactic acid was produced, phytate disappeared, and the concentration of simple sugars decreased substantially. The NSP of the slurry was progressively depolymerized by the enzyme blend. The chemical composition and nutritive value of enzymatically-modified CM (ECM) were evaluated. Ross 308 broilers were randomly assigned to 18 cages of six birds each for the standardized ileal amino acid digestibility (SIAAD) and nitrogen-corrected apparent metabolizable energy (AMEn) assay. A corn/soybean meal-based basal diet formulated to meet Ross 308 breeder recommendations and two test diets contained 70% of the basal diet and 30% of CM or ECM, respectively, were fed to Ross 308 from 13 to 17 d of age. No difference was observed between SIAAD of CM and ECM. The AMEn value of ECM was 2118.0 kcal/kg on a dry matter basis which was 30.9% greater (P < 0.05) than the CM.

Canola meal (CM) is a coproduct of canola oil production which is a valuable protein source for animal nutrition. Its nutritive value can be further enhanced through enzymatic treatment. This process also triggers the fermentation, which results in a decrease in slurry pH, production of lactic acid, disappearance of phytate, and reduction in simple sugars concentration. Moreover, the enzyme blend progressively depolymerized the nonstarch polysaccharides (NSP) of the slurry. No difference was observed between standardized ileal amino acid digestibility of CM and enzymatically-modified CM. The enzymatic modification improved the nitrogen-corrected apparent metabolizable energy of CM for broiler chickens by 30.9%.

Comparative efficacy of a novel Bacillus subtilis-based probiotic and pharmacological zinc oxide on growth performance and gut responses in nursery pigs.

In this study, we assessed the efficacy of a novel Bacillus subtilis probiotic in improving growth performance and gut responses in comparison to pharmacological zinc oxide (ZnO) in nursery pigs. A total of 96 piglets were randomly assigned to four groups: Negative control (NC), Positive control (PC, 3000 mg Zn /kg feed), B.subtilis low dose (BS9-L, 2 × 107 CFU/pig) and B.subtilis high dose (BS9-H, 2 × 109 CFU/pig). Growth performance, diarrhea rate, gut mucosal gene expression and fecal microbial populations were evaluated. B.subtilis administration did not improve piglet bodyweight. BS9-L showed (P < 0.05) higher average daily gain (ADG) in Period 2 (D14-D28). BS9 groups had (P < 0.001) lower feed conversion ratio (FCR) in Period 2 (D14-D28) and overall. Like the ZnO-group, BS9 groups had lower (P < 0.01) diarrhea rate. A significant reduction (P < 0.05) in fecal E. coli, total coliforms, and an increase in lactic acid bacteria and Bacillus spp. in BS9 groups was observed. BS9 group had reduced (P < 0.05) mRNA levels of intestinal IL-8 and higher levels of MUC-1 and occludin and TJP-1 compared to negative control. These findings suggest that probiotic BS9, may promote growth performance, and ameliorate various indicators of intestinal health in piglets. Hence, it may serve as a prospective alternative to ZnO growth promoter in commercial swine production.

Yeast derivatives as a source of bioactive components in animal nutrition: A brief review.

With a long history of inclusion within livestock feeding programs, yeast and their respective derivatives are well-understood from a nutritional perspective. Originally used as sources of highly digestible protein in young animal rations in order to offset the use of conventional protein sources such as soybean and fish meal, application strategies have expanded in recent years into non-nutritional uses for all animal categories. For the case of yeast derivatives, product streams coming from the downstream processing of nutritional yeast, the expansion in use cases across species groups has been driven by a greater understanding of the composition of each derivative along with deeper knowledge of mechanistic action of key functional components. From improving feed efficiency, to serving as alternatives to antibiotic growth promoters and supporting intestinal health and immunity while mitigating pathogen shedding, new use cases are driven by a recognition that yeast derivatives contain specific bioactive compounds that possess functional properties. This review will attempt to highlight key bioactive categories within industrially applicable yeast derivatives and provide context regarding identification and characterization and mechanisms of action related to efficacy within a range of experimental models.

Multi-carbohydrase application into energy and amino acid deficient broiler diets: A strategy to enhance performance of broiler chickens.

The effect of Multi-Carbohydrase (MC) supplementation on growth performance, visceral organ weights, blood metabolites, jejunum morphology, nutrient digestibility, and carcass parameters of broiler chickens fed nutrient-deficient corn soybean-meal based diets containing high levels of non-starch polysaccharides from wheat and wheat by-products was investigated. A total of 378 one-day-old Ross 308 broiler chickens were randomly assigned to one of seven dietary treatments to give six replicates per treatment (nine birds per pen). Dietary treatments were as follows: (1) positive control (PC; commercial standard diet); (2) negative control 1 (NC-1; PC-120 kcal/kg metabolizable energy); (3) NC-2 (PC-3% standardized ileal digestibility [SID] amino acids). The remaining four dietary treatments were formulated with the addition of MC (MC; Superzyme-CS™) into two negative controls along with two supplementation levels of MC (i.e., 0.025% and 0.05%, respectively). Improved body weight, average daily gain, and feed conversion ratio (p < 0.05) were observed in broiler chickens fed a reduced energy diet supplemented with MC compared to birds fed NC-1 diet from days 1-35. Additionally, birds fed a reduced energy diet with 0.05% MC showed comparable (p > 0.05) growth performance with birds fed PC for 35-day post-hatch. Furthermore, the addition of MC into reduced amino acid diets improved (p < 0.05) growth performance. Broiler chickens fed MC supplemented nutrient-deficient diets showed a greater (p < 0.05) villus height to crypt depth ratio than birds fed diets without MC on days 21 and 35. Similarly, improved (p < 0.05) nutrient digestibility was observed in birds fed reduced energy diets supplemented with MC compared to birds fed NC-1 on days 21 and 35. Our results suggest that MC supplementation into reduced energy or reduced amino acid diets containing wheat and wheat by-products has the potential to improve growth performance and nutrient digestibility while maintaining healthier gut morphology in broiler chickens from 1 to 35 days of age.

Fiber degrading enzymes increased monosaccharides release and fermentation in corn distillers dried grains with solubles and wheat middlings steeped without or with protease.

Treating fibrous feed ingredients with exogenous feed enzymes may improve their utilization in monogastric animals. An in vitro study was conducted to determine the effects of steeping corn distillers dried grains with solubles (DDGS) or wheat middlings (WM) with exogenous feed enzymes. Four treatments were arranged as follows: 1) co-product steeped with water (CON), 2) CON plus 0.5-g fiber degrading enzymes (FDE), 3) CON plus 0.5-g protease (PRO), and 4) CON plus 0.5-g FDE and 0.5 g PRO (FDEPRO). The FDE contained about 62,000, 37,000, and 8,000 U/g of xylanase, cellulase, and ß-glucanase, respectively, whereas activities in PRO amounted to 2,500,000, 1,300,000, and 800,000 U/g of acid, alkaline, and neutral proteases, respectively. Briefly, 50 g of DDGS or WM samples (n = 8) were mixed with 500-mL water with or without enzymes and steeped for 0 to 72 h at 37 °C with continuous agitation. The pH, concentration of monosaccharides, and organic acids in the supernatant and apparent disappearance (AD) of fiber in solids were measured at 0, 12, 24, 48, and 72 h. There was treatment and time interaction (P < 0.005) on monosaccharides concentration. At 12 h, arabinose and glucose concentrations were similar (P > 0.05) between FDE and FDEPRO but higher (P = 0.002) than for CON in DDGS. For WM, FDE, and FDEPRO had higher (P < 0.001) xylose concentration than CON and PRO, whereas glucose concentration was higher (P < 0.001) for enzymes than CON at 12 h. However, FDEPRO had higher (P < 0.001) xylose concentration than CON, whereas xylose concentration for FDE and PRO was intermediate at 24 h. There was an interaction (P < 0.05) between treatment and time effect on lactic acid concentration in DDGS and WM (P < 0.005), and acetic acid concentration in WM (P < 0.001). In general, monosaccharide concentration was higher between 12 and 24 h and decreased after 48 h, whereas the pH decreased, and concentration of organic acids increased continuously over time (P < 0.05). The AD of NDF and ADF in DDGS was greater (P = 0.001) for FDE and FDEPRO than CON and PRO at 72 h. In WM, enzymes increased (P = 0.007) AD of NDF relative to CON at 72 h. Nonetheless, greater (P < 0.05) AD of fiber was observed between 48 and 72 h. In conclusion, although there were differences in responses among co-products, fiber degrading enzymes increased release of fermentable monosaccharides from co-products at 12 to 24 h of steeping and these effects were not extended with the addition of protease.

Growth performance, gastrointestinal weight, microbial metabolites and apparent retention of components in broiler chickens fed up to 11% rice bran in a corn-soybean meal diet without or with a multi-enzyme supplement.

We investigated the effects of adding up to 11% rice bran (RB) in corn-soybean meal diets fed to broiler chickens without or with a multi-enzyme supplement (MES). The MES supplied xylanase, ß-glucanase, invertase, protease, cellulase, α-amylase and mannanase with targeted activity of 2,500, 300, 700, 10,000, 1,200, 24,000, and 20 U/kg of feed, respectively. The study used a two-phase feeding program (starter, d 0 to 24; finisher, d 25 to 35) with RB added at 5% and 11%, respectively creating 4 diets in each phase. Diets were iso-caloric and iso-nitrogenous and contained phytase (500 FTU/kg) and TiO2 as a digestibility marker. Three hundred and sixty d-old male Ross 708 broiler chicks were placed in cages based on BW (15 birds/cage) and allocated to 4 diets (n = 6). Birds had free access to feed and water. Body weight and feed intake were recorded. Excreta samples were collected 3 d prior to the end of each phase for apparent retention (AR) of components. Samples of birds were sacrificed on d 24 and 35 for gut weight and ceca digesta for organic acid content. There was no interaction (P > 0.10) between RB and MES on BWG and FCR in starter or finisher phase. In finisher phase, birds fed MES had better BWG (961 versus 858 g) and FCR (1.69 versus 1.86) than birds fed non-MES diets (P < 0.01). Feeding RB reduced (P = 0.02) BWG in finisher phase resulting in lower d 35 BW. Birds fed RB had higher (P ≤ 0.01) gizzard weight on d 24 and 35 than non-RB birds. An interaction (P ≤ 0.01) between RB and MES on concentrations of propionic and iso-butyric acids in ceca digesta showed that MES reduced these acids in non-RB diet. The AR of gross energy was higher (P < 0.02) for MES versus non-MES birds in starter and finisher phases. In conclusion, independently, RB increased gizzard weight and reduced final BW whereas MES improved growth and energy utilization.

Utility of Feed Enzymes and Yeast Derivatives in Ameliorating Deleterious Effects of Coccidiosis on Intestinal Health and Function in Broiler Chickens.

Coccidiosis induced necrotic lesions impair digestive capacity and barrier function in concurrence with increased risks for secondary bacterial infections. The industry has been successful in controlling coccidiosis with anticoccidials and vaccination. However, concerns over Eimeria species resistant to anticoccidials, gaps in vaccination and restriction on antibiotics is stimulating research and application of alternative and/or complimentary strategies for coccidiosis control. The aim of this paper is to appraise literature on the utility of feed enzymes and yeast derivatives in modulating coccidiosis. Feed enzymes can complement endogenous enzymes (protease, amylase, and lipase) that may become insufficient in coccidiosis afflicted birds. Coccidiosis in the upper small intestine creates conditions that enhances efficacy of phytase and there are reports indicating supplemental phytase can mitigate the negative impact of coccidiosis on bone quality. Increase in intestinal short chain fatty acids due supplemental fiber degrading enzymes has been linked with reduced survivability of Eimeria. There is evidence whole yeast (live or dead) and derivatives can modulate coccidiosis. Immunomudulation properties of the yeast derivatives have been shown to enhance cellular and humoral immunity in Eimeria challenge models which is critical for effectiveness of coccidial vaccination. Moreover, yeast nucleotides have been shown to be beneficial in stimulating healing of intestinal mucosal surface. Other novel work has shown that certain yeast cells can produce derivatives with anticoccidial compounds effective in attenuating oocysts shedding. Yeast cell surface has also been shown to be an effective oral Eimeria vaccine delivery vehicle. Overall, while further refinement research is warranted to address inconsistencies in responses and commercial application, there is evidence feed enzymes and yeast derivatives could complement strategies for maintaining intestinal function to bolster growth performance in broilers compromised with coccidiosis. However, broilers receive diets containing several feed additives with distinct mode of actions and yet there is dearth of empirical data on the expected responses.Future evaluations should consider combinations of additives to document animal responses and potential synergies.

Difference in hot carrier cooling rate between Langmuir-Blodgett and drop cast PbS QD films due to strong electron-phonon coupling.

The carrier dynamics of lead sulphide quantum dot (PbS QD) drop cast films and closely packed ordered Langmuir-Blodgett films are studied with ultra-fast femtosecond transient absorption spectroscopy. The photo-induced carrier temperature is extracted from transient absorption spectra and monitored as a function of time delay. The cooling dynamics of carriers in PbS QDs suggest a reduction of the carrier energy loss rate at longer time delays through the retardation of the longitudinal optical (LO) phonon decay due to partial heating of acoustic phonon modes. A slowed hot carrier cooling time up to 116 ps is observed in the drop cast film. A faster cooling rate was also observed in the highly compact Langmuir-Blodgett film due to the enhanced carrier-LO phonon coupling strength arising from the Coulombic interaction in neighboring QDs, which is verified by temperature dependent steady state PL measurements.

Mapping the aberrations of a wide-field spectrograph using a photonic comb.

We demonstrate a new approach to calibrating the spectral-spatial response of a wide-field spectrograph using a fibre etalon comb. Conventional wide-field instruments employed on front-line telescopes are mapped with a grid of diffraction-limited holes cut into a focal plane mask. The aberrated grid pattern in the image plane typically reveals n-symmetric (e.g. pincushion) distortion patterns over the field arising from the optical train. This approach is impractical in the presence of a dispersing element because the diffraction-limited spots in the focal plane are imaged as an array of overlapping spectra. Instead, we propose a compact solution that builds on recent developments in fibre-based, Fabry-Perot etalons. We introduce a novel approach to near-field illumination that exploits a 20cm aperture commercial telescope and the propagation of skew rays in a multimode fibre. The mapping of the optical transfer function across the full field is represented accurately (<0.5% rms residual) by an orthonormal set of Chebyshev moments. Thus we are able to reconstruct the full 4K × 4K CCD image of the dispersed output from the optical fibres using this mapping, as we demonstrate. Our method targets one of the largest sources of systematic error in multi-object spectroscopy, i.e. spectral distortion due to instrumental aberrations, and provides a comprehensive solution to their calibration and removal.

Short-term effect of supplemental yeast extract without or with feed enzymes on growth performance, immune status and gut structure of weaned pigs challenged with Escherichia coli lipopolysaccharide.

BACKGROUND: This study investigated the response of piglets receiving a yeast extract without or with a multi-enzyme mixture compared with an antimicrobial growth promoter (AGP) on performance, immune status and gut structure after an E. coli lipopolysaccharide (LPS) challenge. Thirty-six pigs were allotted to six treatments including: a non-challenged control (NCC); LPS-challenged control (CC); CC + AGP; CC + yeast extract; CC + enzymes; and CC + enzymes + yeast extract. On d 7, pigs were bled and thereafter injected with LPS or sterile saline. Blood samples were collected at 6, 48, and 96 h post-challenge. After 96 h post-challenge, pigs were euthanized to obtain duodenal, jejunal and ileal samples. RESULTS: Overall (d 1 to 11), compared with CC pigs, AGP attenuated the LPS-induced reduction in ADG (P = 0.004), ADFI (P = 0.03) and gain/feed ratio (P = 0.01). At 6 h post-challenge, AGP pigs had lower plasma urea N (PUN; P = 0.02) and serum TNF- α concentration (P = 0.07), and higher platelet count (P = 0.04) and serum IL-10 concentration (P = 0.02) than CC pigs. At 48 h post-challenge, AGP pigs had lower PUN (P = 0.02) than CC pigs, whereas enzymes + yeast extract interacted non-additively (P = 0.001) to reduce PUN. At 96 h post-challenge, AGP pigs had lower PUN (P = 0.02) and higher duodenal (P = 0.03), jejunal (P = 0.01) and ileal (P = 0.07) villus height than CC pigs. In addition, enzymes + yeast extract interacted additively and non-additively to reduce ileal IFN-γ (P < 0.0001) and IL-10 (P = 0.012) expression, respectively. Generally, no differences (P > 0.10) were observed between AGP and enzymes + yeast extract pigs on other measured parameters except for the downregulation of ileal IFN-γ (P < 0.0001) and TNF-α (P = 0.003) in enzymes + yeast extract pigs at 96 h post-challenge. CONCLUSIONS: The LPS challenged piglets receiving enzymes + yeast extract showed beneficial responses in gut structure and immunity commensurate with those receiving antibiotics, though the latter had better overall growth performance.

Dose-response effects of in-feed antibiotics on growth performance and nutrient utilization in weaned pigs fed diets supplemented with yeast-based nucleotides.

Dietary nucleotides are bioactive compounds with the potential to mitigate weaning-associated challenges in piglets. An experiment was conducted to determine the interaction effect of antimicrobial growth promoters (AGP) and a nucleotide-rich yeast extract (NRYE) on growth performance and apparent total tract digestibility (ATTD) of dry matter (DM), crude protein (CP) and gross energy (GE), and to establish whether NRYE supplementation may completely or partially replace AGP in diets for weaned pigs. In phase 1 and 2, corn, wheat, canola meal and soybean meal based diets, which were formulated to contain 0.0 or 0.1% NRYE with 0, 25, 50, 75 or 100% of the recommended AGP dosage, were fed to 108 twenty-one day old piglets (initial body weight 7.11 ± 0.9 kg; mean ± SD) from d 1 to 14 and 15 to 28, respectively. Overall, increasing AGP level in NRYE supplemented diets linearly decreased average daily gain (ADG) (P = 0.002) and gain-to-feed ratio (G:F) (P = 0.007); and quadratically decreased ATTD of DM (P = 0.001), CP (P = 0.003) and G:F (P = 0.017) during phase 2. Compared with control and pigs fed NRYE with 100% of recommended AGP dosage, pigs fed 0.1% NRYE without AGP had greater (P < 0.05) ADG and G:F in phase 2 and overall. In conclusion, supplementing 0.1% NRYE improved growth performance of pigs but this beneficial effect was reduced by increasing dietary AGP dosage.