Apparent total tract macronutrient digestibility, fecal characteristics, and fecal fermentative end-product concentrations of healthy adult dogs fed bioprocessed soy protein.

Animal proteins are commonly used in extruded dog foods. Plant-based proteins have a more consistent nutrient profile than animal sources but may contain antinutritional factors, including trypsin inhibitors and oligosaccharides. Bioprocessed soy protein (SP; HP-300; Hamlet Protein, Inc., Findlay, OH) is a processed soy-based product with low antinutritional factor concentrations and high protein quality. The objective was to evaluate the effects of SP on apparent total tract macronutrient digestibility, fecal characteristics, and fecal fermentative end products. Furthermore, this study aimed to identify if SP can be a replacement for poultry byproduct meal (PBPM) in dog food and determine if there are practical limits to its use. Three palatability experiments were conducted to evaluate 1) 0 vs. 12% SP, 2) 0 vs. 48% SP, and 3) 12 vs. 48% SP. For digestibility, 48 healthy adult Beagle dogs (20 females and 28 males; 3.4 yr mean age and 10.0 kg mean BW) were randomly allotted to 1 of 6 dietary treatments, 0 (control), 4, 8, 12, 24, and 48% SP, in a completely randomized design. All diets were formulated to meet Association of American Feed Control Officials nutrient profiles and contained approximately 30% CP and 16% fat. The treatment period consisted of a 10-d diet adaptation phase followed by a 4-d fresh and total fecal collection phase. The palatability results suggest that of the 3 inclusion levels tested (0, 12, or 48% SP), the best inclusion of SP is 12%, which was preferred over 0 and 48% SP. Digestibility and fecal data were evaluated for linear and quadratic effects using SAS. Stool output (on both an as-is and a DM basis) did not differ from the control except for the 48% SP treatment ( < 0.01). Fecal output per unit food intake differed ( < 0.01) from the control only at the 24 and 48% SP inclusion rates. No significant effects of feeding SP were found on stool consistency scores. Digestibility of DM, OM, and energy did not differ from the control at any inclusion rate, except for a decrease ( < 0.01) at 48% SP. Apparent total tract CP digestibility was not affected by treatment and ranged from 82.9 to 86.2%. Fecal short-chain fatty acid concentrations were greater ( < 0.01) in dogs fed 24 and 48% SP compared with the control. Conversely, branched-chain fatty acid concentrations were lower ( < 0.01) in dogs fed 8 to 48% SP compared with the control. These data suggest that SP is a suitable replacement for PBPM in dog diets up to a 24% inclusion level.

In vitro fermentation characteristics, in vivo ileal and total tract nutrient digestibilities, and fecal microbiota responses of dogs to α-cyclodextrin.

The objectives were to examine in vitro fermentation characteristics, in vivo nutrient digestibility, fecal microbiota, and serum lipid profiles as affected by α-cyclodextrin (ACD) supplementation. Short-chain fatty acid (SCFA) production was measured after in vitro fermentation for 3, 6, 9, and 12 h of ACD, ß-cyclodextrin, and γ-cyclodextrin. Five mixed-breed hounds were used in a Latin square design. Each experimental period comprised 14 d, including 10 d for diet adaptation and 4 d for fecal collection. Dogs were fed, twice a day, an extruded diet made with poultry byproduct meal and brewer's rice as the main ingredients. Dogs were supplemented with 0, 1, 2, 3, or 4 g of ACD diluted in 15 mL of water twice daily for a total of 0, 2, 4, 6, and 8 g ACD/d. Maximal in vitro production of total SCFA was lowest for ACD. However, the greatest maximal production of propionate was noted for ACD treatment. Total tract nutrient digestibility and fecal DM concentration linearly decreased ( < 0.05) for treatment groups receiving ACD; no changes were observed for ileal digestibility. Serum cholesterol and triglyceride concentrations were within normal ranges for dogs and were not different among treatments. Similarly, no changes in fecal microbiota were observed. Overall, ACD supplementation appears to have no effect on nutrient absorption in the small intestine but may alter fermentation in the large bowel, which could lead to a higher proportion of propionate production as observed in the in vitro experiment.

Serum lipid profiles, total tract nutrient digestibility, and gastrointestinal tolerance by dogs of α-cyclodextrin.

The objectives were to quantify gastrointestinal tolerance, total tract nutrient digestibility, and serum lipid profiles of dogs as affected by α-cyclodextrin (ACD) supplementation and to validate the accuracy of fat analyses techniques using novel ACD-fat complexes. The ACD was hydrolyzed and free sugars and hydrolyzed monosaccharides were quantified using high performance liquid chromatography. Known amount of fats were complexed with ACD, and fat content of complexes were determined using the ether extraction and acid-hydrolyzed fat methods. Nine mixed-breed hounds were used in a crossover design with 3 periods of 10 d each, including 6 d for diet adaptation and 4 d for fecal collection. Dogs were fed twice daily a diet with poultry byproduct meal and brewer's rice as the main ingredients, and chromic oxide (0.2%) was included as a digestion marker. Dogs were supplemented with either 0, 3, or 6 g of ACD diluted in 15 mL of water twice per day for a total of 0, 6, and 12 g ACD per day. The ACD had a very low free sugar concentration and, once hydrolyzed, released only glucose, as expected. Average daily food intake, fecal output (DM basis), and fecal scores were not significantly different among treatments. Body weight and condition score and serum triglycerides and cholesterol concentrations remained unaltered throughout the duration of the experiment. Dry matter, OM, and fat digestibility coefficients were lower (P < 0.05) for both treatment groups compared to the control. The acid-hydrolyzed fat method was valid to measure fat that was bound to ACD. Intake of ACD lowered fat digestibility somewhat but not to the extent previously reported, without affecting serum lipid concentrations or outcomes related to tolerance. Therefore, ACD supplementation resulted in a small decrease in fat digestibility, but ACD supplementation might have potential in modifying serum lipid profiles.

Evaluation of soluble corn fiber on chemical composition and nitrogen-corrected true metabolizable energy and its effects on in vitro fermentation and in vivo responses in dogs.

Dietary fermentable fiber is known to benefit intestinal health of companion animals. Soluble corn fiber (SCF) was evaluated for its chemical composition, nitrogen-corrected true ME (TMEn) content, in vitro digestion and fermentation characteristics, and in vivo effects on nutrient digestibility, fecal fermentation end products, and modulation of the fecal microbiome of dogs. Soluble corn fiber contained 78% total dietary fiber, all present as soluble dietary fiber; 56% was low molecular weight soluble fiber (did not precipitate in 95% ethanol). The SCF also contained 26% starch and 8% resistant starch and had a TMEn value of 2.6 kcal/g. Soluble corn fiber was first subjected to in vitro hydrolytic-enzymatic digestion to determine extent of digestibility and then fermented using dog fecal inoculum, with fermentative outcomes measured at 0, 3, 6, 9, and 12 h. Hydrolytic-enzymatic digestion of SCF was only 7%. In vitro fermentation showed increased (P < 0.05) concentrations of short-chain fatty acids through 12 h, with acetate, propionate, and butyrate reaching peak concentrations of 1,803, 926, and 112 µmol/g DM, respectively. Fermentability of SCF was higher (P < 0.05) than for cellulose but lower (P < 0.05) than for pectin. In the in vivo experiment, 10 female dogs (6.4 ± 0.2 yr and 22 ± 2.1 kg) received 5 diets with graded concentrations of SCF (0, 0.5, 0.75, 1.0, or 1.25% [as-is basis]) replacing cellulose in a replicated 5 × 5 Latin square design. Dogs were first acclimated to the experimental diets for 10 d followed by 4 d of total fecal collection. Fresh fecal samples were collected to measure fecal pH and fermentation end products and permit a microbiome analysis. For microbiome analysis, extraction of DNA was followed by amplification of the V4 to V6 variable region of the 16S rRNA gene using barcoded primers. Sequences were classified into taxonomic levels using a nucleotide basic local alignment search tool (BLASTn) against a curated GreenGenes database. Few changes in nutrient digestibility or fecal fermentation end products or stool consistency were observed, and no appreciable modulation of the fecal microbiome occurred. In conclusion, SCF was fermentable in vitro, but higher dietary concentrations may be necessary to elicit potential in vivo responses.

Nutrient and mineral composition during shoot growth in seven species of Phyllostachys and Pseudosasa bamboo consumed by giant panda.

During the annual period of bamboo shoot growth in spring, free-ranging giant pandas feed almost exclusively on the shoots while ignoring the leaves and full- height culm. Little is known about the nutritional changes that occur during bamboo shoot growth, if nutritional changes differ among species, or how these changes might influence forage selection. Our objective was to examine the nutrient and mineral composition during three phases of shoot growth (<60, 90-150 and >180 cm) for seven species of bamboo (Phyllostachys (P.) aurea, P. aureosulcata, P. bissetii, P. glauca, P. nuda, P. rubromarginata, Pseudosasa japonica) fed to captive giant pandas at the Memphis Zoo. Total dietary fiber content of bamboo shoots increased (p < 0.0001) from an overall species average of 61% dry matter (DM) at < 60 cm to 75% DM at shoot heights > 180 cm, while crude protein, fat and ash exhibited significant declines (p < 0.05). Phyllostachys nuda had the overall greatest (p = 0.007) crude protein (21% DM) and fat (4% DM) content, and lowest overall total fibre (61% DM) content compared to the other species examined. In contrast, Pseudosasa japonica had the overall lowest crude protein and fat, and relatively higher fibre content (9%, 3% and 74% respectively). Concentrations of Zn and Fe were highest in shoots <60 cm (10-50 µg/g DM) and decreased (p < 0.05) during growth in all species examined. Concentrations of Ca, Cu, Mn, Na and K varied among species and were largely unaffected by growth stage. Due to their higher concentrations of nutrients and lower fibre content in comparison to culm and leaf, bamboo shoots should be a major component of captive giant panda diets when available.

In vitro fermentation characteristics of novel fibers, coconut endosperm fiber and chicory pulp, using canine fecal inoculum.

The objective of this experiment was to determine the effects of in vitro fermentation of coconut endosperm fiber (CEF), chicory pulp (CHP), and selective blends of these substrates on SCFA production and changes in microbiota using canine fecal inocula. A total of 6 individual substrates, including short-chain fructooligosaccharide (scFOS; a well-established prebiotic source), pectin (PEC; used as a positive control), pelletized cellulose (PC; used as a negative control), beet pulp (BP; considered the gold standard fiber source in pet foods), CEF, and CHP, and 3 CEF:CHP blends (75:25% CEF:CHP [B1], 50:50% CEF:CHP [B2], and 25:75% CEF:CHP [B3]) were tested. Triplicate samples of each substrate were fermented for 0, 8, and 16 h after inoculation. A significant substrate × time interaction (P < 0.05) was observed for pH change and acetate, propionate, butyrate, and total SCFA concentrations. After 8 and 16 h, pH change was greatest for scFOS (-2.0 and -3.0, respectively) and smallest for PC (0.0 and -0.1, respectively). After 16 h, CEF had a greater butyrate concentration than CHP and all the CEF:CHP blends and it was not different than PEC. The substrate × time interaction was significant for bifidobacteria (P < 0.05) and lactobacilli (P < 0.05). After 8 h, bifidobacteria was greatest for BP and lowest for PC (12.7 and 10.0 log10 cfu/tube, respectively). After 16 h, PC had the lowest and scFOS had the greatest bifidobacteria (6.7 and 13.3 log10 cfu/tube, respectively). In general, CEF, CHP, and their blends had similar bifidobacteria populations after 8 and 16 h of fermentation when compared with BP and scFOS. After 16 h, lactobacilli populations were greatest for B1, B2, B3, BP, and scFOS, intermediate for PEC, and lowest for PC (P < 0.05). Overall, our data suggest that CEF had a butyrogenic effect and that CEF, CHP, and their blends had similar bifidobacteria and lactobacilli populations as popular prebiotic and fiber substrates. Future research should investigate the effects of CEF, CHP, and their blends on gastrointestinal health and fecal quality in dogs.

Fructan supplementation of senior cats affects stool metabolite concentrations and fecal microbiota concentrations, but not nitrogen partitioning in excreta.

Fructan supplementation of a commercially available canned cat food was evaluated using senior (≥ 9 yr) cats to assess nitrogen (N) partitioning in excreta and stool metabolite and microbiota concentrations. Oligofructose (OF) or SynergyC (OF+IN) were added to the diet individually at 1% (dry weight basis). Cats were acclimated to the control diet for 7 d and then were randomly assigned to 1 of 3 treatment groups for 21 d (n = 6). Feces and urine were collected on d 22 through 28. No differences were observed in food intake; fecal output, DM percentage, score, pH, or short- or branched-chain fatty acids, fecal and urinary ammonia output, urinary felinine concentrations, or N retention. Supplemental OF+IN tended to decrease N digestibility (P = 0.102) and Bifidobacteria spp. (P = 0.073) and decrease fecal indole (P < 0.05), tyramine (P < 0.05), and Escherichia coli (P < 0.05) concentrations. Both fructan-supplemented treatments decreased (P < 0.05) fecal histamine concentrations. The tendency to a lower apparent N digestibility was likely due to increased colonic microbial protein synthesis of fructan-supplemented cats. Fructan supplementation may benefit senior cats as it modulates stool odor-forming compounds and decreases some protein catabolites and pathogenic gut microbiota concentrations without affecting N retention.

Potato fiber as a dietary fiber source in dog foods.

Potato fiber (PF), a coproduct of potato starch manufacture, was evaluated as a potential novel fiber source in dog food. Potato fiber contained 55% total dietary fiber, 29% starch, 4% crude protein, and 2% acid-hydrolyzed fat. The PF substrate was evaluated for chemical composition, in vitro digestion and fermentation characteristics, and in vivo responses. For the in vitro hydrolytic-enzymatic digestion and fermentation experiment, raw and cooked PF substrates were first subjected to hydrolytic-enzymatic digestion to determine OM disappearance and then fermented using dog fecal inoculum. Fermentation characteristics were then measured at 0, 3, 6, 9, and 12 h. For the in vivo experiment, 10 female mixed-breed dogs (6.13±0.17 yr; 22±2.1 kg) were provided 5 diets with graded concentrations (0%, 1.5%, 3%, 4.5%, or 6%) of PF in a replicated 5×5 Latin square design. Dogs were acclimated to the test diet for 10 d, followed by 4 d of total fecal collection. Fresh fecal samples were collected to measure fecal pH and fermentation end products. In vitro digestion revealed that raw and cooked PF were 32.3% and 27.9% digested enzymatically, whereas in vitro fermentation showed that PF was fermentable through 9 h. Raw PF had greater (P<0.05) acetate, propionate, and total short-chain fatty acid (SCFA) concentrations at the 12-h time point compared with cooked PF. The in vivo experiment showed no differences in apparent total tract DM, OM, CP, acid-hydrolyzed fat, or energy digestibility of diets containing graded concentrations of PF. However, total dietary fiber digestibility exhibited a linear increase (P<0.01) with increasing PF concentrations in the diet. Overall, linear increases (P<0.01) were observed for all individual and total SCFA, with a concomitant linear decrease (P<0.01) in fecal pH with increasing dietary PF. Fecal protein catabolite concentrations were low or undetectable, with the exception of spermidine, which exhibited a linear increase with increasing concentrations of PF. These findings indicated that inclusion of PF elicited favorable fermentation characteristics without negatively affecting nutrient digestibility or stool characteristics, indicating that PF could be a functional dietary fiber source in dog foods.

Comparison of ileal and total tract nutrient digestibility of dry dog foods.

The apparent total tract and ileal digestibility assays to measure AA absorption in commercial canine diets were compared in the present study. Five ileal cannulated dogs were fed 5 commercial dry canine foods selected to contain 19 to 30% CP in a 5 × 5 Latin square design. Ileal and total tract digestibility (apparent and standardized) of DM, OM, CP, crude fat (CF), carbohydrate, and AA (including reactive Lys) were calculated using Cr2O3 as an indigestible marker. Greater apparent total tract digestibility values were found for DM, OM, and CP (P ≤ 0.034) compared with ileal digestibility values; however, CF (P = 0.058) had a greater ileal apparent digestibility. Apparent and standardized CP digestibility values were, respectively, 5.7 and 7.4 percentage units greater when measured over the total digestive tract compared with measurement at the ileum (P = 0.034 and 0.011, respectively). Ileal apparent digestibility for N of AA (P = 0.009) and most AA (P < 0.05), except for Met, Ile, Lys, Phe, and Ala, was decreased if measured at the ileum. However, correction for endogenous losses showed only Met digestibility did not differ between measurement sites. Differences between sites in excess of 15 percentage units were recorded for AA. Apparent and standardized ileal reactive Lys digestibility was 3.1 to 15.3 percentage units greater than corresponding total tract digestibility values. For several indispensable AA, the bioavailability estimates currently used by the 2006 NRC and the 2011 Association of American Feed Control Officials to derive allowance estimates for canine adult maintenance were greater than the digestibility values of these AA in the commercial dog foods evaluated. Although the canine large intestine is relatively short, the total tract digestibility assay in dogs can overestimate the digestibility of dietary AA and CP and may not be an accurate method for the measurement of absorption. In this study, bioavailability estimates of AA appeared to be less than those used to derive allowance estimates for commercial dog foods. Further work is required if current recommendations warrant adjustment.

Blending of soluble corn fiber with pullulan, sorbitol, or fructose attenuates glycemic and insulinemic responses in the dog and affects hydrolytic digestion in vitro.

The objective of these experiments was to measure in vitro hydrolytic digestion and glycemic and insulinemic responses of select carbohydrate blends, all containing the novel carbohydrate soluble corn fiber (SCF). Two SCF that varied in their method of production were used to formulate the carbohydrate blends. One set of blends contained a SCF that was spray dried (SCFsd) and then blended with different amounts of either pullulan, sorbitol, or fructose. The other set of blends contained a SCF produced using longer evaporation time (SCF) and then blended with different ratios of pullulan, sorbitol, and fructose. Free sugar concentrations found in the individual SCFsd and SCF substrates were low but varied. Spray-dried soluble corn fiber had a reduced free sugar concentration compared with SCF (2.8 vs. 14.2%). Glucose was the main free sugar found in both SCFsd and SCF but at different concentrations (2.7 vs. 12.7%, respectively). The majority of the SCFsd blends were completely hydrolyzed to their monosaccharide components. Glucose accounted for most of the hydrolyzed monosaccharides for SCFsd and all the SCFsd blends. Hydrolyzed monosaccharide concentrations for the SCF:pullulan:sorbitol:fructose blends followed similar trends to the SCFsd blends where greater percentages of fructose and sorbitol resulted in decreased (P < 0.05) hydrolyzed monosaccharide concentrations. The SCFsd blends had intermediate to high amounts of monosaccharides released as a result of in vitro hydrolytic digestion. The SCFsd:pullulan blends were more digestible in vitro (approximately 91%; P < 0.05) than SCFsd:fructose or SCFsd:sorbitol. Total released monosaccharides were high in SCFsd blends containing either 50% fructose or sorbitol, but the combination resulted in reduced concentrations of glucose released (P < 0.05). The SCF:pullulan:sorbitol:fructose blends also had intermediate to high released monosaccharides as a result of in vitro hydrolytic digestion. All SCF blends resulted in decreased glycemic and insulinemic responses compared with the maltodextrin control (P < 0.05) using a canine model. The addition of pullulan reduced the glycemic response compared with maltodextrin at all concentrations, but only 50:50 SCFsd:pullulan resulted in a reduction of the glycemic response compared with SCFsd alone (P < 0.05). The addition of fructose and sorbitol in the blends had the greatest impact on glycemic and insulinemic responses, even at concentrations as low as 5% of the blends. Overall, SCF and their blends may prove beneficial as components of low glycemic foodstuffs.

Effects of oligosaccharides in a soybean meal-based diet on fermentative and immune responses in broiler chicks challenged with Eimeria acervulina.

Fermentable oligosaccharides, particularly those found in soybean meal (SBM), may modulate fermentation in the ceca, thus affecting intestinal immune responses to intestinal pathogens. We hypothesized that fermentable oligosaccharides found in SBM would positively affect cecal fermentation and intestinal immune status in chicks challenged with an acute coccidiosis (Eimeria acervulina) infection and fed either a SBM-based diet or a semi-purified soy protein isolate- (SPI) based diet. Using a completely randomized design, 1-d-old broiler chicks (n = 200; 5 replications/treatment; 5 chicks/replication) were assigned to 1 of 4 SBM- or SPI-based diets containing either dietary cellulose (4%) or a fermentable carbohydrate, galactoglucomannan oligosaccharide-arabinoxylan (GGMO-AX) complex (4%). On d 9 posthatch, an equal number of chicks on each diet were inoculated with either distilled water (sham control) or E. acervulina (1 × 10(6) oocysts) and then euthanized on d 7 postinoculation. Overall, body weight gain and feed intake were greater (P < 0.01) for SBM-fed chicks, regardless of infection status. Gain:feed ratio was greater (P ≤ 0.05) for SPI-fed chicks except during d 3-7 postinoculation. Infection status, but not fiber source, affected propionate, isobutyrate, isovalerate, and total branched-chain fatty acid concentrations (P ≤ 0.02). Soybean meal-based diets resulted in greater (P ≤ 0.04) short-chain fatty acid and branched-chain fatty acid concentrations than SPI-based diets. Messenger RNA fold changes relative to uninfected SBM-cellulose-fed chicks of all duodenal cytokines were greater (P ≤ 0.01) for infected chicks, and SBM-fed chicks had greater (P < 0.01) interferon-γ and interleukin-12ß expression compared with SPI-fed chicks. Cecal tonsil cytokine expression was also affected (P ≤ 0.02) by infection; however, protein source only affected (P < 0.01) interleukin-1ß expression in this tissue. Overall, a SBM-based diet, compared with a semi-purified SPI-based diet with a different ingredient composition, resulted in greater weight gain, feed intake, and short-chain fatty acid production regardless of infection status, and also greater duodenal cytokine expression in E. acervulina- infected chicks, which is hypothesized to be related to the nutrients and oligosaccharides found in SBM.

In vitro digestibility of expanded pork skin and rawhide chews, and digestion and metabolic characteristics of expanded pork skin chews in healthy adult dogs.

Chews are an important part of the pet product industry, with many having potential to decrease plaque or calculus formation. However, their digestion characteristics and gut transit time are virtually unknown. Two experiments were conducted to determine in vitro DM digestibility of expanded pork skin chews and rawhide chews, and apparent total tract digestibility (ATTD), gastrointestinal transit time, and blood metabolite measurements in healthy adult dogs fed a weight-control commercial diet and expanded pork skin chews. In Exp.1, an in vitro method that simulated gastric and small intestinal digestion was used to determine DM digestibility of expanded pork skin chews and rawhide chews. In Exp. 2, after a 22-d baseline phase, 10 purpose-bred, intact female dogs (5 to 5.5 yr of age; 18.9 to 23.1 kg BW) were fed the diet plus an expanded pork skin chew (~45 g) each day for 22 d. In vitro gastric digestibility of expanded pork skin chews increased with time, with chews being 54.7%, 58.6%, 76.4%, and 86.4% digestible after 6, 12, 18, and 24 h of gastric digestion, respectively. By contrast, gastric digestibility of rawhide chews was 7.6% at 6 h, slowly increased over time, and reached a maximum of 41.6% at 18 h. In vitro gastric plus small intestinal digestibility results indicated near complete digestibility of expanded pork skin chews at all times, whereas rawhide chews were 50 to 85% digestible. In vivo ATTD of DM, OM, and N were greater (P < 0.05) when dogs were fed expanded pork skin chews along with the basal diet, compared with the basal diet alone. However, chew intake did not change transit time measured with a wireless motility device. By contrast, motility index and contraction pattern of the colon were altered (P < 0.05) during chew feeding relative to control. Blood urea N concentrations were greater (P < 0.05) in dogs fed expanded pork skin chews, compared with baseline; this was not surprising, given the increased N intake and absorption from the chews. Intake of expanded pork skin chews resulted in reduced blood cholesterol concentrations (P < 0.05) and tended to decrease blood triglyceride concentrations (P < 0.10). Expanded pork skin had a greater DM digestibility than rawhide chews. In addition, expanded pork skin decreased blood cholesterol and triglyceride concentrations, which may justify further research in this area.

Ingestion of a novel galactoglucomannan oligosaccharide-arabinoxylan (GGMO-AX) complex affected growth performance and fermentative and immunological characteristics of broiler chicks challenged with Salmonella typhimurium.

Fermentable carbohydrates may enhance the ability of the gastrointestinal tract to defend against a pathogenic infection. We hypothesized that a galactoglucomannan oligosaccharide-arabinoxylan (GGMO-AX) complex would positively affect immune status and prevent colonization and shedding in Salmonella typhimurium-infected chicks. Using a completely randomized design, 1-d-old commercial broiler chicks (n = 240 chicks; 4 replications/treatment; 5 chicks/replication) were assigned to 1 of 6 dietary treatments differing in concentration of GGMO-AX (0, 1, 2, or 4%) or containing 2% Safmannan or 2% short-chain fructooligosaccharides. Cellulose was used to make diets iso-total dietary fiber. On d 10 posthatch, an equal number of chicks on each diet were inoculated with either phosphate-buffered saline (sham control) or Salmonella typhimurium (1 × 10(8) cfu). All birds were euthanized on d 10 postinoculation (PI) for collection of intestinal contents and select tissues. Body weight gain and feed intake of chicks were greater (P < 0.05) in infected chicks PI for all time periods, except for weight gain on d 0 to 3 PI. Gain:feed was affected (P < 0.05) by diet, with Safmannan-fed chicks having the highest G:F and 1% GGMO-AX-fed chicks having the lowest. The GGMO-AX substrate demonstrated effects similar to a prebiotic substrate as indicated by increased cecal short-chain fatty acid concentrations, decreased cecal pH, and increased populations of Lactobacillus spp. and Bifidobacteria spp. as dietary GGMO-AX concentration increased. Excreta Salmonella typhimurium populations on d 5 and 10 PI, and ileal and cecal Salmonella typhimurium populations, tended to be affected (P < 0.10) by the main effect of diet. Messenger RNA expression of IFN-γ in the cecal tonsils was the only cytokine independently affected by infection and diet (P < 0.01). Chicks fed 2 and 4% GGMO-AX had similar expressions of IFN-γ and IL-1ß, regardless of infection, suggesting that Salmonella typhimurium virulence was suppressed. Dietary supplementation with GGMO-AX resulted in prebiotic-like effects but did not limit Salmonella typhimurium intestinal colonization or shedding, but possibly decreased the virulence of Salmonella typhimurium within the digestive tract.

The effects of a galactoglucomannan oligosaccharide-arabinoxylan (GGMO-AX) complex in broiler chicks challenged with Eimeria acervulina.

Fermentable carbohydrates may enhance the ability of the gastrointestinal tract to defend against pathogenic infection. We hypothesized that a mannose-rich, galactoglucomannan oligosaccharide-arabinoxylan (GGMO-AX) complex would positively impact immune status and prevent weight loss resulting from acute coccidiosis (Eimeria acervulina) infection of chicks. Using a completely randomized design, 1-d-old commercial broiler chicks (n = 160; 4 replications/treatment; 5 chicks/replication) were assigned to one of 4 corn-soybean meal-based diets containing supplemental GGMO-AX (0, 1, 2, or 4%) that replaced dietary cellulose. On d 9 posthatch, an equal number of chicks on each diet were inoculated with either distilled water (sham control) or E. acervulina (1 × 10(6) oocysts). All birds were euthanized on d 7 postinoculation (PI) for collection of cecal contents and duodenal tissue. Overall, BW gain of chicks was not affected by diet PI, whereas infection decreased (P < 0.01) weight gain on d 0 to 7 PI. Feed intake was not affected by dietary treatment, but infection decreased (P < 0.01) feed intake on d 0 to 7 PI. Overall, infection, but not diet, decreased (P < 0.01) G:F on d 0 to 7 PI. Cecal propionate concentrations were independently affected by infection and diet, while butyrate concentrations were affected only by infection (P = 0.02). Cecal Bifidobacterium spp. populations were affected (P < 0.01) by diet, with the 2% GGMO-AX resulting in the highest cfu/g of cecal contents (on a DM basis). Messenger RNA expression of all duodenal cytokines evaluated was affected by infection status (P ≤ 0.02) but not by dietary treatment alone. Supplementing 4% GGMO-AX consistently resulted in the greatest fold change in proinflammatory cytokine expression, while inhibiting antiinflammatory cytokine expression, which indicates a more robust innate immune response. Despite decreasing performance, 4% dietary GGMO-AX improved select fermentation indices and the innate intestinal immune response to an acute E. acervulina infection.

Adaptation of healthy adult cats to select dietary fibers in vivo affects gas and short-chain fatty acid production from fiber fermentation in vitro.

Nine young adult (1.73 ± 0.03 yr) male cats were used to determine the effects of microbial adaptation to select dietary fiber sources on changes in pH in vitro and on total and hydrogen gas, short-chain fatty acid (SCFA), and branched-chain fatty acid (BCFA) production. Cats were adapted to diets containing 4% cellulose, fructooligosaccharides (FOS), or pectin for 30 d before fecal sampling. Each cat was used as a single donor, and fecal inoculum was reacted with each of the aforementioned fiber substrates. Adaptation to dietary FOS resulted in a greater change in pH when exposed to FOS than pectin (adaptation × substrate, P < 0.001). When exposed to the FOS substrate, adaptation to dietary FOS or pectin increased hydrogen gas production (adaptation × substrate, P = 0.021). Adaptation to dietary FOS increased acetate and total SCFA production when exposed to FOS substrate in vitro (adaptation × substrate, P = 0.001). When exposed to the FOS substrate, propionate production tended to increase with adaptation to dietary cellulose (adaptation × substrate, P = 0.060). The BCFA + valerate tended to decrease with adaptation to dietary FOS when exposed to FOS substrate in vitro (adaptation × substrate, P = 0.092). Fructooligosaccharides resulted in the greatest change in pH and production of total gas (P < 0.001), hydrogen gas (P < 0.001), acetate (P < 0.001), propionate (P < 0.001), butyrate (P < 0.001), total SCFA (P < 0.001), and total BCFA + valerate production (P < 0.001). Adaptation to the FOS or pectin diet increased production of hydrogen gas with FOS and pectin substrates. Adaptation to pectin increased (P = 0.033) total gas production with FOS and pectin substrates. Overall, adaptation to either FOS or pectin led to greater SCFA and gas production, but adaptation to FOS resulted in the greatest effect overall.

Effect of corn distillers dried grains with solubles and Eimeria acervulina infection on growth performance and the intestinal microbiota of young chicks.

Chicks were used to determine whether dietary corn distillers dried grains with solubles (DDGS) may prevent or ameliorate Eimeria acervulina (EA) infection. The experiment had a completely randomized design with a factorial arrangement of 3 diets (inclusion of 0, 10, or 20% DDGS) × 2 challenge treatments: inoculation with distilled water or with 10(6) sporulated EA oocysts. Each treatment was replicated with 8 pens of 5 chicks each. Experimental diets were fed from 7 to 21 d of age. Inoculation occurred on d 10 of age, considered postinoculation (PI) d 0. Feed intake and BW were measured on PI d 0, 7, and 14. Excreta samples were collected on PI d 0, 5 to 10, 12, and 14 to detect oocysts. On PI d 14, mucosal samples were collected for the analysis of bacterial populations by denaturing gradient gel electrophoresis, using the V3 region of bacterial 16S ribosome. The EA challenge reduced (P < 0.001) ADG by 17%, ADFI by 12%, and G:F by 6% from PI d 0 to 7, and by smaller percentages from PI d 7 to 14. Diet and challenge treatments did not interact in the chick performance, so dietary DDGS did not alleviate EA infection. Oocysts in excreta were detected PI only in EA chicks and no dietary effects were found. Cecal bacterial population was changed (P < 0.05) by effect of dietary DDGS and EA infection. The cecal bacterial diversity among chicks within treatments and homogeneity among chicks within treatments were reduced by EA infection (P = 0.02 to 0.001) and increased by feeding 10% DDGS (diet quadratic, P < 0.001). In summary, feeding up to 20% DDGS to young chicks did not prevent or ameliorate EA infection. Changes in cecal microbiota of chicks fed 10% DDGS can be interpreted as beneficial for intestinal health.

Effects of short-chain fructooligosaccharides and galactooligosaccharides, individually and in combination, on nutrient digestibility, fecal fermentative metabolite concentrations, and large bowel microbial ecology of healthy adults cats.

Short-chain fructooligosaccharides (scFOS) and galactooligosaccharides (GOS) are nondigestible oligosaccharides that result in a prebiotic effect in some animal species; however, the cat has not been well studied in this regard. This experiment evaluated scFOS and GOS supplementation on nutrient digestibility, fermentative end product production, and fecal microbial ecology of cats. Eight healthy adult cats were fed diets containing no prebiotic, 0.5% scFOS, 0.5% GOS, or 0.5% scFOS + 0.5% GOS (scFOS + GOS) in a replicated 4 × 4 Latin square design. Apparent total tract CP digestibility was decreased (P < 0.05) when cats were fed a diet containing scFOS + GOS compared with the other treatments. Dry matter, OM, acid hydrolyzed fat, and GE digestibilities were not different (P > 0.05) among treatments. Cats fed scFOS-, GOS-, and scFOS + GOS-supplemented diets had greater (P < 0.05) fecal Bifidobacterium spp. populations compared with cats fed the control diet. Fecal pH was less (P < 0.05) for cats fed the scFOS + GOS-supplemented diet compared with the control. Butyrate (P = 0.05) and valerate (P < 0.05) concentrations were greater when cats consumed the scFOS + GOS diet. Acetate tended (P = 0.10) to be greater when cats were fed the scFOS + GOS diet. Total short-chain fatty acid (P = 0.06) and total branched-chain fatty acid (P = 0.06) concentrations also tended to be greater when cats consumed the scFOS + GOS treatment. Fecal protein catabolites, including ammonia, 4-methylphenol, indole, and biogenic amines, blood lymphocytes, neutrophils, total white blood cell counts, or fecal DM concentration and output did not differ (P > 0.05) among treatments. Low level supplementation of scFOS, GOS, and their combination exert positive effects on select indices of gut health in cats.

Galactoglucomannan oligosaccharide supplementation affects nutrient digestibility, fermentation end-product production, and large bowel microbiota of the dog.

A galactoglucomannan oligosaccharide (GGMO) obtained from fiberboard production was evaluated as a dietary supplement for dogs. The GGMO substrate contained increased concentrations of oligosaccharides containing mannose, xylose, and glucose, with the mannose component accounting for 35% of DM. Adult dogs assigned to a 6 × 6 Latin square design were fed 6 diets, each containing a different concentration of supplemental GGMO (0, 0.5, 1, 2, 4, and 8%) that replaced dietary cellulose. Total tract DM and OM apparent digestibilities increased (P < 0.001) linearly, whereas total tract CP apparent digestibility decreased (P < 0.001) linearly as dietary GGMO substrate concentration increased. Fecal concentrations of acetate, propionate, and total short-chain fatty acids increased (P ≤ 0.001) linearly, whereas butyrate concentration decreased (P ≤ 0.001) linearly with increasing dietary concentrations of GGMO. Fecal pH decreased (P ≤ 0.001) linearly as dietary GGMO substrate concentration increased, whereas fecal score increased quadratically (P ≤ 0.001). Fecal phenol (P ≤ 0.05) and indole (P ≤ 0.01) concentrations decreased linearly with GGMO supplementation. Fecal biogenic amine concentrations were not different among treatments except for phenylethylamine, which decreased (P < 0.001) linearly as dietary GGMO substrate concentration increased. Fecal microbial concentrations of Escherichia coli, Lactobacillus spp., and Clostridium perfringens were not different among treatments. A quadratic increase (P ≤ 0.01) was noted for Bifidobacterium spp. as dietary GGMO substrate concentration increased. The data suggest positive nutritional properties of supplemental GGMO when incorporated in a good-quality dog food.

Inclusion of psyllium in milk replacer for neonatal calves. 2. Effects on volatile fatty acid concentrations, microbial populations, and gastrointestinal tract size.

Fermentable fibers such as psyllium increase volatile fatty acid (VFA) concentrations in the lower digestive tract and increase the gastrointestinal tract (GIT) mass of many mammals. We reasoned that psyllium inclusion in milk replacer might produce similar effects in neonatal dairy calves, which could lead to improved growth and health. Male Holstein calves were fed a milk replacer (22% crude protein, 20% fat) either without or with psyllium (1.1% of dry matter, DM) from 2 d through 28 d of age. Milk replacer was reconstituted to 12.5% DM and fed at 12% of calf body weight, adjusted weekly. Water was offered ad libitum but no starter was fed. Three calves per treatment were harvested weekly to sample digesta from the reticulo-rumen, abomasum, jejunum, proximal colon, and distal colon, and to determine length and mass of GIT components. Psyllium in milk replacer increased the proportion of butyrate in reticulo-rumen contents from 2.4 to 3.2% of total but did not affect total VFA concentrations. Total VFA concentrations were very low in the jejunum but psyllium tended to increase total VFA, acetate, and valerate concentrations; valerate accounted for 15.9 and 16.7% of total VFA (molar basis) for control and psyllium calves, respectively. Psyllium increased total VFA concentrations in the proximal and distal colon by 104.4 and 45.6%, respectively, but had little effect on the profile of VFA. Psyllium in milk replacer increased populations of bifidobacteria (from 9.7 to 10.3 log(10) cfu/g of DM) and lactobacilli (from 8.2 to 9.4 log(10) cfu/g of DM) in the reticulo-rumen, but did not affect populations in jejunum or colon. Calves fed psyllium had 12.0% greater total GIT mass and 9.4% greater GIT as a percentage of body weight. Psyllium tended to increase mass of the reticulo-rumen and significantly increased mass of duodenum (34.2%), jejunum (14.5%), and colon (14.6%). Density of intestinal tissues from calves fed psyllium-supplemented milk replacer was 25.9% greater in the jejunum and 25.3% greater in the ileum, and tended to be greater in duodenum and colon than tissue from control calves. Supplementation of psyllium to milk replacer increased fermentation in the colon, mass of the total GIT, and populations of bifidobacteria and lactobacilli in the reticulo-rumen.

Inclusion of psyllium in milk replacer for neonatal calves. 1. Effects on growth, digesta viscosity, rate of passage, nutrient digestibilities, and metabolites in blood.

Based on research in other species, inclusion of psyllium in milk replacer might improve nutrient utilization and gastrointestinal function in neonatal calves. Male Holstein calves were fed a milk replacer (22% crude protein, 20% fat) either without or with psyllium (1.1% of dry matter) from 2 d through 28 d of age. Milk replacer was reconstituted to 12.5% dry matter (DM) and fed at 12% of calf body weight (BW), adjusted weekly. Water was offered ad libitum but no starter was fed. Three calves per treatment were harvested weekly to sample digesta from the rumen, abomasum, jejunum, proximal colon, and distal colon. Mean daily intakes of water, DM, crude protein, and metabolizable energy did not differ between treatments. Average daily gain of BW did not differ between treatments. Digesta from the abomasum and colon of calves fed psyllium was more viscous than digesta from control calves. Mean retention time of digesta in the total digestive tract tended to be greater for calves supplemented with psyllium (9.7 vs. 8.4h). Feces and digesta from the proximal and distal colon of calves fed psyllium had lower DM content than feces and digesta from control calves. Total-tract apparent digestibility of DM (92.8 vs. 94.1%) was lower for psyllium-fed calves, likely as an effect of the addition of the more poorly digestible psyllium; digestibilities of energy and ash also tended to be lower. The prefeeding plasma glucose concentration (10h after previous feeding) tended to be greater for psyllium-fed calves but concentrations of nonesterified fatty acids, beta-hydroxybutyrate, cholesterol, urea N, and total protein did not differ between treatments. Blood components did not differ between treatments at 2h postfeeding. Inclusion of psyllium in the milk replacer of neonatal calves increased digesta viscosity and slowed passage of digesta through the gastrointestinal tract.