Effect of β-mannanase on the digestibility of diets with different protein sources in dogs determined by different methodologies

This experiment aimed at evaluating the effects of including the enzyme, β-mannanase, in dog (Canis lupus familiaris) diets based on either poultry (Gallus gallus domesticus) by-product meal (PBM) or soybean [Glycine max (L.) Merr.] Meal (SBM). The second objective was to evaluate 3 methods for determining energy and nutrient digestibility values in diets fed to dogs: total fecal collection (TFC) and use of aia or crude fiber (CF) as a marker. Eight dogs were allotted to a replicated latin square (4 by 4) design. There were 2 diets based on PBM as the major protein source and 2 diets based on SBM as the major protein source. Within each protein source, 1 diet contained no β-mannanase and 1 diet contained 0.01% β-mannanase. Diets were fed for an adaptation period of 5 d followed by 5 d of TFC. Fecal score (1 = watery feces to 5 = dry, hard pellets), pH, DM, and fecal volume were determined. The apparent total tract digestibility (ATTD) of DM, OM, CP, ether extract (EE), N-free extract (NFE), and GE, and ME content were calculated using the methods of TFC, AIA, and CF. Data were analyzed as a 2 by 2 by 3 split-split-plot design (β-mannanase, protein source, and digestibility calculation procedure). There were interactions between protein source and β-mannanase (P < 0.05). Supplementation of β-mannanase increased ATTD of nutrients and energy and ME (+ 195.3 kcal/kg) and also reduced fecal production in the diet with SBM, but not in the diet that contained PBM. There was an interaction between digestibility calculation procedure and protein source (P < 0.05). The use of AIA overestimated ATTD of the diets containing PBM, but digestibility values estimated based on TFC and CF were not different. Dogs fed diets containing SBM produced more feces with greater moisture content and lower pH compared with dogs fed the PBM diet (P < 0.05). Addition of 0.01% β-mannanase increased (P < 0.05) the digestibility and ME content of the diets containing SBM, but did not improve (P > 0.05) fecal texture. Results indicated that values for ATTD of energy and nutrients in diets containing sbm are not different if they are calculated based on TFC, AIA, or CF, but use of AIA may result in an overestimation of values for ATTD of energy and nutrients in diets containing PBM.     

Effects of exogenous enzyme supplementation to corn- and soybean meal-based or complex diets on growth performance, nutrient digestibility, and blood metabolites in growing pigs

Two experiments were conducted to determine the effects of dietary supplementation of exogenous enzymes on growth performance, apparent total tract digestibility (ATTD) of energy and nutrients, blood metabolites, fecal VFA, and fecal ammonia-N in growing pigs (Sus scrofa) fed a corn (Zea mays L.)- and soybean [Glycine max (L.) Merr.] meal (SBM)-based diet. In Exp. 1, 240 growing barrows (initial BW: 55.6 ± 0.9 kg) were randomly allotted to 5 treatments on the basis of BW. There were 4 replicates in each treatment with 12 pigs per replicate. The 5 treatments consisted of a corn-SBM-based control diet and 4 additional diets were similar to the control diet, with the exception that 0.05% β-mannanase (M), α-amylase + β-mannanase (AM), β-mannanase + protease (MPr), or α-amylase + β-mannanase + protease (AMP) was added to the diets, which were fed for 28 d. Pigs fed the AM, MPr, or AMP diet had greater (P < 0.05) ADG than pigs fed the control diet. Pigs fed the AMP diet also had greater (P < 0.05) ADG than pigs fed the M, AM, or MPr diet. Pigs fed the AMP diet had greater (P < 0.05) G:F than pigs fed the control diet. The G:F of the pigs fed the M, AM, or MPr diet were not different (P > 0.05) from the G:F in pigs fed the AMP or control diet. The ADFI, ATTD of nutrients, blood metabolites, and fecal VFA and ammonia-N concentrations were not different among treatments. In Exp. 2, 192 growing barrows (initial BW: 56.9 ± 1.0 kg) were allotted to 4 treatments. There were 4 replicates in each treatment with 12 pigs per replicate. Pigs were fed a corn-SBM-based diet (CSD) or a complex diet (CD) that contained corn, SBM, 3% rapeseed (Brassica napus L.) meal, 3% copra (Cocos nucifera L.) meal, and 3% palm (Elaeis guineensis Jacq.) kernel meal. Each diet was prepared without exogenous enzymes or with 0.05% AMP and all diets were fed for 28 d. The ADG and G:F of pigs fed the CSD were greater (P < 0.05) than pigs fed the CD. However, the type of diet had no effect on the ATTD of nutrients, blood metabolites, or fecal VFA and ammonia-N, and there was no diet × enzyme interaction for any of the measured variables. Supplementation of diets with exogenous enzymes resulted in greater (P < 0.05) ADG, G:F, ATTD of DM, GE, and CP, and blood urea nitrogen (BUN) concentration. These results indicate that supplementation of 0.05% of AMP enzymes to a corn-SBM diet or a complex diet may improve the performance of growing pigs.     

Nutrient digestibility and fecal characteristics,microbiota, and metabolites in dogs fed human-grade foods

Human-grade (HG) pet foods are commercially available, but they have not been well studied. Our objective was to determine the apparent total tract digestibility (ATTD) of HG pet foods and evaluate their effects on fecal characteristics, microbiota, and metabolites, serum metabolites, and hematology of dogs. Twelve dogs (mean age = 5.5 ± 1.0; BW = 11.6 ± 1.6 kg) were used in a replicated 4 × 4 Latin square design (n = 12/treatment). The diets included 1) Chicken and Brown Rice Recipe (extruded; Blue Buffalo); 2) Roasted Meals Tender Chicken Recipe (fresh; Freshpet); 3) Beef and Russet Potato Recipe (HG beef; JustFoodForDogs); and 4) Chicken and White Rice Recipe (HG chicken; JustFoodForDogs). Each period consisted of 28 d, with a 6-d diet transition phase, 16 d of consuming 100% of the diet, a 5-d phase for fecal collection, and 1 d for blood collection. All data were analyzed using the Mixed Models procedure of SAS 9.4. Dogs fed the extruded diet required a higher (P < 0.05) daily food intake (dry matter basis, DMB) to maintain BW. The ATTD of dry matter (DM), organic matter (OM), energy, and acid-hydrolyzed fat (AHF) were greater (P < 0.05) in dogs fed the HG diets than those fed the fresh diet, and greater (P < 0.05) in dogs fed the fresh diet than those fed the extruded diet. Crude protein ATTD was lower (P < 0.05) for dogs fed the extruded diet than those fed all other diets. Dogs fed the extruded diet had greater (P < 0.05) fecal output (as-is; DMB) than dogs fed fresh (1.5–1.7 times greater) or HG foods (2.0–2.9 times greater). There were no differences in fecal pH, scores, and metabolites, but microbiota were affected by diet. Dogs fed HG beef had higher (P < 0.05) relative abundance of Bacteroidetes and lower (P < 0.05) relative abundance of Firmicutes than dogs fed the fresh or HG chicken diets. The Actinobacteria, Fusobacteria, Proteobacteria, and Spirochaetes phyla were unchanged (P > 0.05), but diet modified the relative abundance of nearly 20 bacterial genera. Similar to previous reports, these data demonstrate that the fecal microbiota of dogs fed HG or fresh diets is markedly different than those consuming extruded diets, likely due to ingredient, nutrient, and processing differences. Serum metabolites and hematology were not greatly affected by diet. In conclusion, the HG pet foods tested resulted in significantly reduced fecal output, were highly digestible, maintained fecal characteristics, serum chemistry, and hematology, and modified the fecal microbiota of dogs.     

Evaluation of graded levels of Bacillus coagulans GBI-30, 6086 on apparent nutrient digestibility,stool quality,and intestinal health indicators in healthy adult dogs

Bacillus coagulans GBI-30, 6086 is a commercially available spore-forming non-toxigenic microorganism approved for use in dog foods with high resiliency to stresses associated with commercial manufacturing. The objectives of this research were to examine the effect of B. coagulans on stool quality, nutrient digestibility, and intestinal health markers in healthy adult dogs. Extruded diets containing graded levels of B. coagulans applied either to the base ration before extrusion or to the exterior of the kibble as a topical coating after extrusion were randomly assigned to 10 individually housed adult beagle dogs (7 castrated males and 3 spayed females) of similar age (5.75 ± 0.23 yr) and body weight (12.3 ± 1.5 kg). The study was designed as a 5 × 5 replicated Latin square with 16-d adaptation followed by 5-d total fecal collection for each period. Five dietary treatments were formulated to deliver a dose of 0-, 6-, 7-, 8-, and 9-log₁₀ colony-forming units (CFU) per dog per day for the control (CON), extruded B. coagulans (PEX), and low, moderate, and high B. coagulans coating levels (PCL, PCM, and PCH), respectively. Food-grade TiO₂ was added to all diets at a level of 0.4% to serve as an indigestible dietary marker for digestibility calculations. Data were analyzed using a mixed model through SAS (version 9.4, SAS Institute, Inc., Cary, NC) with treatment as a fixed effect and room (i.e., replicate), period, and dog(room) as random effects. Apparent total tract digestibility of organic matter, crude protein, crude fat, and gross energy calculated by the marker method were numerically greatest for dogs fed the 9-log₁₀ dose treatment with increases (P < 0.05) observed in gross energy and organic matter digestibility compared with the negative control. No significant differences were observed in food intake, stool quality, fecal pH, fecal ammonia, fecal short-chain fatty acids, or branched-chain fatty acids for the extruded B. coagulans treatment (PEX) or the coated B. coagulans treatments (PCL, PCM, and PCH) compared with CON. These results suggest that B. coagulans has a favorable impact on nutrient digestibility and no apparent adverse effects when added to extruded diets at a daily intake level of up to 9-log₁₀ CFU in healthy adult dogs.     

Growth performance,nutrient digestibility,and fecal microbial composition of weaned pigs fed multi-enzyme supplemented diets

A study determined the effects of supplementing corn-based diets for weaned pigs with multi-enzymes on growth performance, apparent total tract digestibility (ATTD) of nutrients, fecal score, and fecal microbial composition. A total of 132 pigs (initial body weight = 7.23 kg) that had been weaned at 21 d of age and fed a drug-free nursery diet for 7 d were housed in 33 pens of 4 barrows or gilts, blocked by body weight and gender, and fed 3 experimental diets at 11 pens per diet. The diets were corn-based diet without or with multi-enzyme A or B. Multi-enzyme A supplied 4,000 U of xylanase, 150 U of β-glucanase, 3,500 U of protease, and 1,500 U of amylase per kilogram of diet. Multi-enzyme B was the same as multi-enzyme A except that it supplied amylase at 150 U/kg, and that its source of amylase was different from that of multi-enzyme A. All diets contained phytase at 1,000 U/kg. The diets were fed for 35 d in 2 phases; phase 1 for the first 14 d and phase 2 for the last 21 d of the trial. Fecal score was determined daily during the first 7 d of the trial. Fecal samples were collected from rectum of 1 pig per pen on days 2, 7, 14, and 35 of the trial for determining bacterial composition. Also, fresh fecal samples were collected from each pen on days 41 and 42 to determine ATTD of nutrients. Multi-enzyme B increased (P < 0.05) average daily gain (ADG) for phases 1 and 2. For the overall study period, multi-enzyme B increased (P < 0.05) ADG from 262 to 313 g, and average daily feed intake (ADFI) from 419 to 504 g. Multi-enzyme A increased (P < 0.05) overall ADG from 262 to 290 g, but did not affect ADFI. Multi-enzyme A or B did not affect ATTD of gross energy, but increased (P < 0.05) the ATTD of ether extract from 30% to 36% or 37%, respectively. Multi-enzyme A did not affect fecal score; however, multi-enzyme B tended to decrease (P = 0.09) fecal score, implying that it tended to decrease diarrhea. Firmicutes were the most abundant phylum of fecal bacteria (its relative abundance ranged from 58% to 72%). Bacteroidetes and Actinobacteria were the 2nd and 3rd most abundant phyla of fecal bacteria. Neither multi-enzyme affected fecal bacterial composition. In conclusion, the addition of multi-enzyme A or B to phytase-supplemented corn-based diet for weaned pigs can improve their growth performance and fat digestibility. However, multi-enzyme B was more effective than multi-enzyme A in terms of improving the growth performance of weaned pigs fed corn-based diet.     

Supplementation of protease,alone and in combination with fructooligosaccharide to low protein diet for finishing pigs

Effects of adding protease with or without fructooligosaccharide (FOS) to low protein diet on growth performance, nutrient digestibility and fecal noxious gas emission were evaluated in 160 finishing pigs (57.70 ± 1.16 kg) in a 9‐week study. Pigs were randomly divided into four dietary treatments, PC: positive control diet (15.97% crude protein (CP)); NC: negative control diet (12.94% CP); PRO: NC supplemented with 0.05% protease; PROFOS: NC supplemented with 0.05% protease and 0.1% FOS. During weeks 4–9 and weeks 0–9, gain : feed ratio was impaired (P < 0.05) in pigs fed NC diet compared with those fed PC, PRO and PROFOS diets. Pigs fed PC, PRO and PROFOS diets had higher (P < 0.05) apparent total tract digestibility (ATTD) of CP than pigs fed NC diet. Pigs fed PROFOS diet had reduced (P < 0.05) ammonia emissions compared to pigs fed NC and PRO diets. These data indicate that reducing dietary CP concentrations impaired growth performance, decreased ATTD of CP and reduced ammonia emissions. Supplementation of protease in low CP diet improved growth performance and increased ATTD of CP. Dietary supplementation with protease and FOS in low CP diet improved growth performance, increased ATTD of CP and decreased fecal ammonia emission.     

The effect of texturized vegetable protein from soy on nutrient digestibility compared to beef in cannulated dogs

Texturized vegetable protein from soy (TVP) is widely used in canned dog foods, but its nutritional value remains in doubt. This study compared apparent prececal and total intestinal digestibility when four canned diets containing reciprocal proportions of protein from TVP (0 to 57%) and from beef (100 to 43%) were fed to eight cannulated dogs. As dietary TVP increased, the following linear changes were observed (P < 0.05): prececal and total intestinal protein digestibility decreased slightly from 77 to 71% and 86 to 80%, respectively; prececal amino acid digestibility decreased in parallel with protein; prececal carbohydrate digestibility decreased markedly from 80% to 62% and carbohydrate disappearance in the large intestine increased from 8 to 22%; prececal sodium digestibility decreased markedly (from 37 to 4%); and prececal potassium digestibility decreased (from 93 to 85%). Total intestinal digestibility of sodium and potassium decreased little (from 97 to 95% and from 98 to 97%, respectively); fecal mass and water content increased markedly (from 98 to 174 g/d and from 61 to 72%, respectively); and fat digestibility was unaffected. Prececal phosphorus digestibility from two diets containing TVP was lower than that from the all-beef diet (13 and 17%, vs 26%, P < 0.05). In conclusion, TVP is a useful source of protein in canine canned diets because amino acids from TVP are almost as digestible as those from beef in the canine intestine. Nevertheless, soy carbohydrate is poorly digested and large amounts of TVP inhibit small intestinal electrolyte digestibility and increase fecal water content.     

Effect of potential multimicrobe probiotic product processed by high drying temperature and antibiotic on performance of weanling pigs

In this study, the effect of a potential multimicrobe probiotic subjected to high-temperature drying was investigated. Potential multimicrobe probiotics produced by solid substrate fermentation were dried at low (LT, 40°C for 72 h) or high (HT, 70°C for 36 h) temperature. In Exp. 1, 288 weaned pigs (BW, 6.43 ± 0.68 kg) were allotted to 4 treatments on the basis of BW (4 pens per treatment with 18 pigs in each pen). Dietary treatments were negative control (NC; basal diet without any antimicrobial), positive control (PC; basal diet + 0.1% chlortetracycline), basal diet with 0.3% probiotic LT, and basal diet with 0.3% probiotic HT. Diets were fed in 2 phases, phase I (d 0 to 14) and phase II (d 15 to 28); and growth performance, apparent total tract digestibility (ATTD, d 28), and fecal microflora (d 14 and 28) were evaluated. Over the 28-d trial, pigs fed PC and probiotic diets had greater ADG (P < 0.001), ADFI (P < 0.05), and G:F (P < 0.01) than pigs fed NC diet. The ATTD of DM and GE was greater (P < 0.05) in pigs fed probiotic diets when compared with pigs fed the NC diet. At d 28, fewer Clostridia (P < 0.01) were identified in the feces of pigs fed PC and probiotic diets than pigs fed the NC diet. However, the performance, ATTD of DM and GE, and fecal Clostridia population were similar among pigs fed probiotic LT and HT diets. In Exp. 2, 288 weaned pigs (initial BW, 5.84 ± 0.18 kg) were allotted to 4 treatments in a 2 × 2 factorial arrangement on the basis of BW. The effects of 2 levels of probiotic HT (0.30 or 0.60%), each with or without antibiotic (chlortetracycline, 0 or 0.1%), on performance, ATTD, intestinal morphology, and fecal and intestinal microflora were investigated. Feeding of 0.60% probiotic HT diet improved (P < 0.05) overall ADG, ATTD of DM and GE, and Lactobacillus population in the feces and intestine, and reduced the population of Clostridium and coliforms in feces (d 14) and ileum. Inclusion of antibiotic improved (P < 0.05) the overall ADG, ADFI, and ATTD of DM at d 14 and reduced fecal Clostridium population at d 28. Increased (P < 0.05) villus height at jejunum and ileum, and villus height:crypt depth at the ileum was noticed in pigs fed 0.60% probiotic HT and antibiotic diets. In conclusion, high drying temperature had no effect on the efficacy of potential multimicrobe probiotic product. However, the probiotic product dried at high temperature was more effective at 0.60% inclusion, whereas inclusion of an antibiotic improved pig performance but did not show any interaction with probiotics.     

Corn hybrid affects in vitro and in vivo measures of nutrient digestibility in dogs

Corn is a commonly used ingredient in dry pet foods because there is a stable supply and it is a relatively inexpensive source of nutrients. Corn hybrids are available that are higher in CP and amylose and lower in phytate concentration than conventional hybrids. Approximately 500 mg of high-protein (HP), high-protein, low-phytate (HPLP), and high-amylose (HA) corn were compared with conventional (CONV) corn and amylomaize starch (AM) in triplicate and exposed to pepsin/hydrochloric acid and pancreatin to simulate hydrolytic digestion. Substrate remaining after this was used to determine in vitro colonic fermentation. Organic matter disappearances as a result of hydrolytic digestion were >80% for CONV, HP, and HPLP, whereas HA (60.7%) and AM (43.7%) were lower (P < 0.05). Total digestion (TD) values after hydrolytic digestion and 8 h of fermentation using canine fecal inoculum were greater (P < 0.05) for CONV, HP, and HPLP vs. HA and AM. The residue left after hydrolytic digestion of all substrates was poorly fermented. Five ileal-cannulated dogs were fed each corn hybrid at approximately 31% of the diet in a 5 x5 Latin square design. Dogs fed diets containing HP corn had higher (P < 0.05) ileal OM digestibility (70.3%) and tended (P < 0.10) to have higher DM digestibility (64.6%). Ileal starch digestibilities were lower (P < 0.05) for dogs fed HA (64.0%) and AM (63.0%). Ileal digestibilities of essential (71.2%), nonessential (67.4%), and total (69.0%) AA tended to be higher (P < 0.10) for HP diets compared with CONV (66.4, 62.4, and 64.0%, respectively). Total-tract DM, OM, CP, and GE digestibilities (77, 82, 77, and 84%, on average, respectively) were higher (P < 0.05) for dogs fed CONV, HP, and HPLP than for those fed AM (66.9, 71.6, 72.6, and 76.5%) and HA (60.6, 65.7, 69.7, and 71.5%). Total-tract fat digestibilities were lower (P < 0.05) for dogs fed HA diets (86.6%) than for all other treatments (91.0%, on average). Total-tract starch digestibilities were higher (P < 0.05) for dogs fed CONV, HP, and HPLP (98%, on average) compared with HA (72.8%) and AM (76.5%). No differences were detected among treatments in fecal bifidobacteria, lactobacilli, or Clostridium perfringens concentrations. The experiments demonstrated that HP and HPLP corn had hydrolytic digestion and fermentation characteristics similar to those of CONV corn, whereas HA resulted in similar responses to AM, a well-established resistant starch ingredient.     

Digestibility and safety of dry black soldier fly larvae meal and black soldier fly larvae oil in dogs

Two trials were conducted to assess the acceptance, safety and digestibility of diets containing various inclusion levels of partially defatted black soldier fly (Hermetia illucens) larvae (BSFL) meal and BSFL oil by dogs. In trial 1, 5 extruded diets were evaluated for acceptance in adult Beagle dogs (n = 20; 10 male, 10 female) during a 48-hr period. Diets contained graded levels of BSFL meal (5.0%, 10.0%, and 20.0%), or graded levels of BSFL oil (2.5% and 5.0%), and all diets were well accepted. Thus, a digestibility trial (trial 2) was run with 56 adult dogs (16 male, 40 female) allocated into 7 dietary treatments; dogs were offered an extruded control diet containing no BSFL meal or oil, or extruded diets where BSFL meal partially replaced poultry by-product meal and corn meal at dietary levels of 5%, 10%, or 20% inclusion, or diets with BSFL oil partially replacing poultry fat at a 1:1 ratio at levels of 1%, 2.5%, or 5% inclusion. The treatment diets were fed for 28 d, during which time dogs were monitored for health (via physical examinations, clinical observations, and blood chemistry and hematology) and ingredient evaluation (via body weight, feed consumption, stool observation, and fecal nutrient apparent total tract digestibility). There were no significant differences in body weight or food consumption between treatment groups (P > 0.05) and daily observations indicated that the general health of the animals was maintained throughout the study. Stool quality was maintained at 3.2 to 3.4 (on a 5-point scale with a score of 1 being watery diarrhea and a score of 5 being hard, dry, and crumbly) per treatment group over the fecal observation period (days 22 to 27), indicating a well formed, sticky stool. All group mean hematology and blood chemistry parameters remained within normal limits for dogs. Apparent total tract digestibility of dry matter, protein, fat, and calories was not affected by treatment (P > 0.05). In general, amino acid digestibility was not impacted by treatment although some minor changes were observed. Apparent total tract digestibility was high for all nutrients examined. Overall, it was concluded that BSFL meal and BSFL oil are well tolerated by dogs and their consumption results in no impact to physiology that would be concerning. Based on these data, BSFL meal and oil did not affect general health and could be included safely in dog diets.     

Evaluation of fermentable oligosaccharides in diets fed to dogs in comparison to fiber standards

Blends of fermentable oligosaccharides in combination with nonfermentable fiber, cellulose, were evaluated for their ability to serve as dietary fibers in dog foods. Using a 6 x 6 Latin square design, 6 diets were evaluated that contained either no supplemental fiber, beet pulp, cellulose, or blends of cellulose, fructooligosaccharides, and yeast cell wall added at 2.5% of the diet. Six ileal-cannulated dogs were fed 175 g of their assigned diet twice daily. Chromic oxide served as a digestibility marker. Nutrient digestibility, fecal microbial populations, fermentative end products, and immunological indices were measured. Total tract DM and OM digestibilities were lowest (P < 0.05) for the cellulose treatment. Crude protein digestibility was lower (P < 0.05) for the treatments containing carbohydrate blends. The cellulose treatment had the lowest (P < 0.05) concentration of bacteria, and all diets containing fermentable fiber had greater (P < 0.05) fecal bifidobacteria concentrations compared with the diets without supplemental fermentable fiber. Lactobacilli concentrations tended to be greater (P < 0.08) in treatments containing fermentable fiber compared with the cellulose treatment. Bifidobacteria and lactobacilli concentrations were similar for the beet pulp treatment compared with the fermentable oligosaccharide blends. Total fecal short-chain fatty acid concentration was greater for the beet pulp treatment (P < 0.05) compared with the control and cellulose treatments. The treatments containing fermentable fiber had greater (P < 0.05) fecal butyrate concentrations compared with cellulose and control treatments. Immune indices were not affected by treatment. Our results suggest that dog foods containing blends of fermentable and nonfermentable carbohydrates produce similar physiological results as dog food containing beet pulp as a fiber source. Therefore, blends of these carbohydrates could be useful substitutes for beet pulp in dog foods.     

Ileal and total tract nutrient digestibilities and fecal characteristics of dogs as affected by soybean protein inclusion in dry, extruded diets

Plant-based protein sources are generally less variable in chemical composition than animal-based protein sources. However, relatively few data are available on the nutrient digestibilities of plant-based protein sources by companion animals. The effects of including selected soybean protein sources in dog diets on nutrient digestion at the ileum and in the total tract, as well as on fecal characteristics, were evaluated. Six protein sources were used: soybean meal (SBM), Soyafluff 200W (soy flour), Profine F (traditional aqueous-alcohol extracted soy protein concentrate [SPC 1]), Profine E (extruded SPC [SPC 2]), Soyarich I (modified molecular weight SPC [SPC 3]), and poultry meal (PM). All diets were extruded and kibbled. Test ingredients varied in CP and fat contents; however, diets were formulated to be isonitrogenous and isocaloric. Nutrient intakes were similar, except for total dietary fiber (TDF), which was lower (P < 0.01) for dogs fed the PM diet. Apparent ileal digestibilities of DM, OM, fat, and TDF were not different among treatments; however, CP digestibility at the terminal ileum was higher (P < 0.01) for diets containing soy protein sources than for PM. Total tract CP digestibility was greater (P < 0.01) for soy protein-containing diets than for PM. Apparent total tract digestibilities of DM, OM, fat, and TDF were not different among treatments. Apparent amino acid digestibilities at the terminal ileum, excluding methionine, threonine, alanine, and glycine, were higher (P < 0.01) for soy protein-containing diets than for PM. Dogs fed SPC diets had lower (P < 0.01) fecal outputs (g asis feces/g DMI) than dogs fed the SF diet, and dogs fed SBM tended (P < 0.11) to have lower fecal outputs than dogs fed the SF diet. However, dogs fed the PM diet had lower (P < 0.03) fecal outputs than dogs fed SPC-containing diets. Fecal outputs and scores reflected the TDF and nonstructural carbohydrate contents of the soy protein fraction. Soy protein sources are well utilized by the dog prior to the terminal ileum, and SPC offers a viable alternative to PM as a protein source in dry, extruded canine diets.     

Influence of dietary phosphorus concentration on the digestibility of phosphorus in monocalcium phosphate by growing pigs

An experiment was conducted to test the hypothesis that the dietary inclusion rate of P does not influence the digestibility of P. The experiment was conducted at 4 experiment stations where the same protocol was followed. A total of 60 growing pigs (initial BW: 22.22 +/- 2.13 kg) were allotted to 6 dietary treatments with 10 replications per treatment. All pigs were placed in metabolism cages that allowed for the total, but separate, collection of urine and fecal materials. Six diets were formulated. The basal diet was based on corn (54.2%), soybean meal (20%), and cornstarch. No inorganic P was used, and the total concentration of P in the basal diet was calculated to be 0.29%. Five additional diets were formulated by adding monocalcium phosphate (MCP) in increments of 0.34% to the basal diet and thereby creating diets that were calculated to contain 0.36, 0.43, 0.50, 0.57, and 0.64% total P, respectively. Ground limestone was also added to these diets to maintain a calculated Ca:P ratio of 1.2:1. The balances of Ca and P and the apparent total tract digestibility (ATTD) of Ca and P were calculated for each diet. The contribution of P from the basal diet was then subtracted from the MCP-containing diets to calculate the balance and ATTD for P in MCP. Results of the experiment showed that the absorption and retention of both Ca and P increased (linear, P < 0.001) with increasing concentrations of Ca and P in the diet. The ATTD for Ca ranged from 62.3 to 66.8% and was not influenced by the dietary concentration of Ca. However, the ATTD for P increased from 38.4 to 65.2% as increasing levels of MCP were added to the diet (linear, P < 0.001). Increasing P intake from MCP increased (linear, P < 0.001) the excretion of P in the feces, but the quantity of P that was absorbed and retained also increased (linear, P < 0.001) as more P from MCP was added to the diet. When measured as a percentage of P intake, P retention was not influenced by the dietary P concentration. The ATTD for P in MCP ranged from 79.5 to 88.5% and was not affected by the concentration of P in the diet. Results of this experiment demonstrated that the digestibility and absorption of P from MCP are not influenced by the dietary concentration of P.     

Intrinsic phytase in hybrid rye increases the digestibility of phosphorus in corn and soybean meal in diets fed to growing pigs

An experiment was conducted to test the hypothesis that inclusion of hybrid rye in diets containing corn and soybean meal (SBM) without or with microbial phytase improves the apparent total tract digestibility (ATTD) and the standardized total tract digestibility (STTD) of P because of the intrinsic phytase activity in hybrid rye. Forty-eight growing barrows (initial body weight: 39.5 ± 7.7 kg) were allotted to six diets. A basal diet containing corn and SBM; a rye-based diet; and a diet containing corn, SBM, and rye were formulated. Each diet was formulated without and with microbial phytase (500 units/kg of diet) for a total of six diets. Fecal samples were collected for 4 d following a 5-d adaptation period according to the marker-to-marker procedure. Results indicated that no interactions between diets and concentration of phytase were observed for any of the response criteria measured. The ATTD and STTD of P and the ATTD of Ca differed (P < 0.05) among diets, but regardless of diet, the concentration of P in feces was reduced (P < 0.05) by adding microbial phytase to the diets. As a consequence, microbial phytase increased (P < 0.05) ATTD and STTD of P, and the ATTD of Ca was also increased (P < 0.05) by the use of microbial phytase. Measured values for the ATTD and STTD of P in the diets containing corn, SBM, and hybrid rye without or with phytase were greater (P < 0.05) than values that were predicted based on the ATTD and STTD of P for the corn–SBM and the hybrid rye diet. The observation that STTD predicted from the individual ingredients underestimated the STTD of P in the mixed diet indicates that the intrinsic phytase in hybrid rye resulted in increased digestibility of the P in the corn and SBM included in the corn–SBM–hybrid rye diet. In conclusion, microbial phytase increased the ATTD and STTD of P and the ATTD of Ca regardless of feed ingredients used in diets fed to pigs. In addition, the intrinsic phytase from hybrid rye increased the ATTD and STTD of P in corn and SBM.     

Effect of feeding acidified or fermented barley using Limosilactobacillus reuteri with or without supplemental phytase on diet nutrient digestibility in growing pigs

Fermentation of cereal grains may degrade myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP₆) thereby increasing nutrient digestibility. Effects of chemical acidification or fermentation with Limosilactobacillus (L.) reuteri with or without phytase of high β-glucan hull-less barley grain on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and gross energy (GE), standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AAs), and standardized total tract digestibility (STTD) of P were assessed in growing pigs. Pigs were fed four mash barley-based diets balanced for water content: 1) unfermented barley (Control); 2) chemically acidified barley (ACD) with lactic acid and acidic acid (0.019 L/kg barley grain at a ratio of 4:1 [vol/vol]); 3) barley fermented with L. reuteri TMW 1.656 (Fermented without phytase); and 4) barley fermented with L. reuteri TMW 1.656 and phytase (Fermented with phytase; 500 FYT/kg barley grain). The acidification and fermentation treatments occurred for 24 h at 37 °C in a water bath. The four diets were fed to eight ileal-cannulated barrows (initial body weight [BW], 17.4 kg) for four 11-d periods in a double 4 × 4 Latin square. Barley grain InsP₆ content of Control, ACD, Fermented without phytase, or Fermented with phytase was 1.12%, 0.59%, 0.52% dry matter (DM), or not detectable, respectively. Diet ATTD of DM, CP, Ca, and GE, digestible energy (DE), predicted net energy (NE) value, and urinary excretion of P were greater (P < 0.05) for ACD than Control. Diet ATTD of DM, CP, Ca, GE, DE and predicted NE value, urinary excretion of P was greater (P < 0.05), and diet AID of Ca and ATTD and STTD of P tended to be greater (P < 0.10) for Fermented without phytase than Control. Diet ATTD of GE was lower (P < 0.05) and diet ATTD and STTD of P, AID and ATTD of Ca was greater (P < 0.05) for Fermented with phytase than Fermented without phytase. Acidification or fermentation with/without phytase did not affect diet SID of CP and AA. In conclusion, ACD or Fermented without phytase partially degraded InsP₆ in barley grain and increased diet ATTD of DM, CP, and GE, but not SID of CP and most AA in growing pigs. Fermentation with phytase entirely degraded InsP₆ in barley grain and maximized P and Ca digestibility, thereby reducing the need to provide inorganic dietary P to meet P requirements of growing pigs.     

Selected animal and plant protein sources affect nutrient digestibility and fecal characteristics of ileally cannulated dogs.

The objective of this study was to compare ileal and total tract nutrient digestibilities and fecal characteristics of dogs fed selected animal and plant protein sources incorporated into grain-based diets. Four crude protein sources--soybean meal (SBM), poultry meal (PM), poultry by-product meal (PBPM), and beef and bone meal (BBM)--were fed to four ileal cannulated dogs in a 4 x 4 Latin square design. Intakes of dry matter, organic matter, crude protein, and fat by dogs were similar. Total dietary fiber (TDF) intake was highest for the SBM treatment compared to other treatments. Ileal digestibilities of DM, OM, CP, fat, and TDF were not affected by treatment. Total tract digestibility of DM was lower for the BBM and SBM diets, while OM digestibility was lower for the SBM treatment only. Total tract CP digestibility was similar for BBM, PBPM, and SBM treatments and was higher for the PM treatment. As-is fecal excretion [g/d] was greater when dogs received the SBM treatment. Fecal output on a DM basis was higher for the SBM treatment compared to the other treatments. All diets were well utilized by the dogs as assessed by ileal and total tract digestibility data and fecal characteristics.     

The effects of thermal treatment of field peas (Pisum sativum L.) on nutrient and energy digestibility by growing pigs

An experiment was conducted to measure the effect of thermal treatment on the digestibility of CP, AA, starch, NDF, ADF, and energy in field peas fed to growing pigs. Five pea-containing diets were formulated. The peas included in these diets were either not heat-treated (control) or extruded at 75, 115, or 155 degrees C or pelleted at 75 degrees C. A N-free diet was also included in the experiment to measure basal endogenous losses of CP and AA. The 6 diets were fed to 6 growing pigs (initial BW: 69.3 +/- 2.9 kg) that were allotted to dietary treatments in a 6 x 6 Latin square design. A T-cannula was installed in the distal ileum of each pig, allowing for the collection of ileal digesta. Each experimental period lasted 9 d; fecal samples were collected on d 6 and 7, and ileal samples were collected on d 8 and 9 of each period. Apparent ileal digestibilities (AID) for CP, AA, starch, and energy and standardized ileal digestibility values (SID) for CP and AA were calculated. Apparent total tract digestibilities (ATTD) for NDF, ADF, starch, and energy were also calculated. As the extrusion temperature increased, the AID and SID for CP and all AA, except Pro, increased (quadratic, P < 0.05). In contrast, except for Arg and Pro, the peas that were pelleted at 75 degrees C had AID and SID for CP and AA that were similar to those obtained for the control peas but less (P < 0.05) than the AID for the peas that were extruded at 75 degrees C. The AID for starch and energy increased (linear, P < 0.001) as the extrusion temperature increased to 155 degrees C (from 89.8 to 95.9% and from 71.5 to 79.0%, respectively), but the AID for starch and energy in the pelleted diet was not different from the AID in the control diet (90.1 vs. 89.8% and 69.1 vs. 71.5%, respectively). The ATTD for starch varied from 98.6 to 99.7% and did not differ among treatments. Likewise, no differences were observed for the ATTD of NDF and ADF. However, the ATTD for energy in the diets increased from 89.0 to 93.3% (linear and quadratic, P < 0.05) as field peas were extruded, and the ATTD for energy in the pelleted diet was also greater (P < 0.05) than that of the control diet (91.6 vs. 89.0%). In conclusion, extrusion of field peas increases the AID of CP, AA, starch, and energy and the ATTD of energy. Pelleting field peas at 75 degrees C does not influence the AID of nutrients or energy but improves the ATTD of energy.     

Evaluation of selected high-starch flours as ingredients in canine diets.

Cereal grains represent 30 to 60% of the DM of many companion animal diets. Once incorporated into a diet, the starch component of these grains can provide an excellent source of ME. However, crystallinity and form of starch are variable and can cause incomplete digestion within the gastrointestinal tract. Diets fed in this experiment included one of six high-starch flours as the main source of carbohydrate. The flours originated from barley, corn, potato, rice, sorghum, and wheat. The diets were extruded and kibbled. Starch fraction concentrations of flours consisted of nearly 100% rapidly digestible starch (RDS) and slowly digestible starch (SDS) combined. Starch fraction concentrations of diets paralleled concentrations in flours. Flours varied widely in concentrations of CP, fat, starch, and total dietary fiber. Ileal OM and CP digestibilities were lowest for the potato flour treatment (74 and 64%, respectively). Ileal and total tract starch digestibilities were different (P<.05) among treatments; however, the starch component of all diets was nearly completely digested (>99%). Total tract digestibility of DM and OM was lowest for sorghum (80 and 84%, respectively) compared to all other diets. Crude protein digestibility was highest for corn (87%). Wet fecal weights tended (P<.08) to be greatest for dogs fed the barley treatment (175 g/d). However, dry fecal weights (dried at 55 degrees C) were greatest for dogs consuming the sorghum diet (51 g/d). Fecal scores were consistently greater (i.e., looser stools) for the barley treatment. Any of these flours could be used without negative effects on digestion at either the ileum or in the total tract. Fecal consistency data for dogs consuming the barley treatment indicate that diets containing large amounts (>50%) of barley may not be advantageous for dog owners who house their animals indoors for most of the day.     

Concentration of dietary calcium supplied by calcium carbonate does not affect the apparent total tract digestibility of calcium, but decreases digestibility of phosphorus by growing pigs

A regional experiment was conducted to test the hypothesis that the concentration of dietary Ca does not affect the digestibility of Ca or P in diets fed to growing pigs. Six diets based on corn, potato protein isolate, cornstarch, and soybean oil were formulated. All diets also contained monosodium phosphate, crystalline AA, salt, and a vitamin-micromineral premix. The only difference among the diets was that varying concentrations of calcium carbonate were used to create diets containing 0.33, 0.46, 0.51, 0.67, 0.92, and 1.04% Ca. All diets contained between 0.40 and 0.43% P. Six universities participated in the experiment and each university contributed 2 replicates to the experiment for a total of 12 replicates (initial BW: 23.1 ± 4.4 kg). Pigs were placed in metabolism cages that allowed total, but separate, collection of feces and urine from the pigs. Pigs within each replicate were randomly allotted to the 6 diets and fed experimental diets for 14 d with urine and feces being collected over a 5-d period. Diets, feces, and urine samples were analyzed for Ca and P, and the daily balance, the apparent total tract digestibility (ATTD), and the retention of Ca and P were calculated. Results indicated that intake, fecal excretion, and urinary excretion of Ca increased (linear, P<0.05) as dietary Ca concentration increased. The daily intake of P was not affected by the dietary concentration of Ca, but fecal excretion of P increased (linear, P<0.05) as dietary Ca concentrations increased. In contrast, urinary P output was decreased (linear, P<0.05) as dietary Ca increased. The retention of Ca increased (linear, P<0.05) from 1.73 to 4.60 g/d, whereas the retention of P decreased (linear, P<0.05) from 1.98 to 1.77 g/d as dietary Ca concentrations increased. However, if calculated as a percentage of intake, both Ca and P retention were decreased (linear, P<0.05) as dietary Ca concentration increased (from 55.4 to 46.1% and from 48.4 to 43.5%, respectively). The ATTD of Ca was not affected by the dietary concentration of Ca, but the ATTD of P was decreased (linear, P<0.05) from 56.9 to 46.2% as dietary Ca concentration increased. It is concluded that the dietary concentration of Ca does not affect the ATTD of Ca in calcium carbonate, but increased concentrations of dietary Ca may decrease the ATTD of P in diets based on corn, potato protein isolate, and monosodium phosphate.     

The effect of short-term phytase supplementation on the apparent total tract digestibility of calcium and phosphorus and the reproductive performance of late gestation and lactating sows fed diets without mineral phosphorus

The objective of this study was to measure apparent total tract digestibility (ATTD) of Ca and P as well as reproductive performance in late gestation and lactating sows supplemented with a novel phytase and to compare the response to phytase supplementation between late gestation and lactating sows. A total of 45 late gestation sows and 45 lactating sows were used in experiments 1 and 2, respectively, in a completely randomized design. The sows were provided with a control diet or the control diet supplemented with 187.5 or 375 FYT phytase/kg feed for 10 days. The diets were prepared according to the formulas in use for production but without any inorganic P supplement. Titanium dioxide was included at 3 g/kg feed as an indigestible marker. Each dietary treatment was replicated with 15 sows individually housed in farrowing stalls. The sows were allowed to adapt to the experimental diets for 5 days before a 5-d fecal collection by grab sampling, and the performance of the sows and their litters were measured until weaning. The results showed that the ATTD of Ca increased linearly (P < 0.001), while the ATTD of P increased both linearly and quadratically (P < 0.01) with increasing supplementation of phytase in both late gestation and lactating sows. There was no significant effect of phytase on the ATTD of dry matter, crude protein, and gross energy, and the performance of the sows and their progenies. The phytase added at 187.5 and 375 FYT/kg feed released 0.07% and 0.10% digested P, respectively, in late gestation sows, which compared with 0.09% and 0.12% digested P in lactating sows. In conclusion, a novel phytase at 187.5–375 FYT/kg feed could release 0.07–0.12% digestible P for sows. It appeared that using the P digestibility values of feed ingredients listed by NRC to formulate a diet for sows might overestimate dietary P supply and a greater response to phytase supplementation could be expected in lactating sows than in late gestation sows.