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.

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.

Osseous metaplasia in the eye of a dog.

Incisional iris biopsy was performed for diagnosis of an unusual opaque white mass protruding from the right ventrolateral iris of a 10-year-old neutered male Great Dane dog. Histopathology revealed a diagnosis of bone formation within otherwise normal iris tissue. No underlying etiology was identified. Osseous metaplasia or heterotopic bone formation may be an additional differential diagnosis for a nonneoplastic mass in the eye of a dog.

Influence of amount and degradability of protein on production of milk and milk components by lactating Holstein cows.

Forty-one multiparous cows were utilized in a completely randomized design with a 2 x 2 factorial arrangement of treatments to evaluate the amount and degradability of dietary CP on production of milk and milk components. The TMR contained 25% alfalfa haylage, 25% corn silage, and 50% concentrate to provide either 16.4 or 19.4% CP with a calculated ruminal degradability of 55 or 70%. Intakes of DM, ADF, and NDF and BW were not different among treatments. Production of milk, 4% FCM, fat, CP, and SNF was not affected by amount or degradability of dietary CP. Milk CP percentage was not affected significantly by amount or degradability of CP. Milk fat percentage was increased by the diet that was high in ruminally undegradable protein (2.90 and 3.12; low and high ruminally undegradable protein, respectively). These data suggest that synthesis of milk and milk components was not limited by a shortage of AA or that the different dietary sources of supplemental CP did not alter AA availability.

Dose titration of sustained-release recombinant bovine somatotropin in lactating dairy cows.

Lactating dairy cows (n = 264) were used in seven dose titration experiments at four geographic locations in the United States. A sustained-release formulation of recombinant bST was evaluated for a 30-wk treatment period that began 14 wk postpartum. The first series of four experiments evaluated doses of 0, 140, 350, or 700 mg of bST/14 d (series A); the second series evaluated doses of 0, 56, 140, or 350 mg of bST/14 d (series B). Milk yield, DMI, milk composition, body condition, health, and reproductive parameters were measured. Multiparous cows in series A that were administered 700 mg of bST/14 d yielded 3.0 kg/d more milk and 3.5% FCM than control cows. When all seven experiments were combined, multiparous cows that were administered 350 mg of bST/14 d yielded 2.7 and 2.6 kg/d more milk and 3.5% FCM than control cows. Dry matter intake was not significantly affected by bST administration. In series A, an increase in milk yield with no increase in DMI resulted in lower adequacy of dietary NEL and CP to meet maintenance and yield requirements among multiparous cows administered 700 mg of bST/14 d. Primiparous cows that were administered bST in series A and both parity groups in the combined seven experiments were not different from control cows in the adequacy of dietary NEL or CP to meet maintenance and yield requirements. No adverse effects of bST on health parameters were significant, and doses of 350 mg of bST/14 d or less caused no changes in reproductive parameters. Conception rate was decreased by administration of 700 mg of bST/14 d. These data suggest that 350 mg of bST/14 d increased yields of milk and FCM with no adverse effects on DMI, health, or reproduction in dairy cows.

Effects of somatotropin and duodenal infusion of amino acids on nutrient passage to duodenum and performance of dairy cows.

Four multiparous Holstein cows were used in a 4 x 4 Latin square to investigate the effects of bST and postruminal infusion of lysine and methionine on ruminal fermentation, flow of nutrients to the small intestine, and animal performance. The treatments were 1) control; 2) control plus 24 g of lysine and 8 g of methionine/d; 3) control plus 25 mg of bST/d; and 4) control plus 25 mg of bST/d plus 24 g of lysine and 8 g of methionine/d. Intakes of DM, OM, CP, starch, NDF, and ADF were similar among treatments. Ruminal characteristics, flow of nutrients to the small intestine, and total tract apparent digestibilities of nutrients were not affected by injection of bST or postruminal infusion of lysine and methionine in this short-term experiment. Milk production, 4% FCM, milk fat percentage and yield, and production of milk CP were increased by administering bST. Postruminal infusion of lysine and methionine did not affect milk production or composition.

Effects of calcium salts of fatty acids and protein source on ruminal fermentation and nutrient flow to duodenum of cows.

Four Holstein cows fitted with ruminal and duodenal cannulas were used in a 4 x 4 Latin square to investigate the effects of calcium salts of long-chain fatty acids (fat) and source of protein (fish meal or soybean meal) on ruminal fermentation, flow of nutrients to the small intestine, and animal performance. Cows were fed for ad libitum intake a diet of 30% alfalfa haylage, 20% corn silage, and 50% concentrate on a DM basis. Treatments, arranged in a 2 x 2 (fat x protein) factorial, were 1) soybean meal, no fat; 2) soybean meal, fat; 3) fish meal, no fat; and 4) fish meal, fat. Intake of DM was not affected by fat or protein source, but feeding fat decreased the amount of OM truly digested in the rumen. Starch intake was decreased, but flow of starch to the duodenum was not altered by feeding fat. Nonammonia N and microbial N flows to the duodenum were not affected by treatment comparisons. However, efficiency of microbial growth was increased by feeding fat, but not by source of protein. Passage of amino acids to the duodenum was not affected by source of protein, probably because fish meal contributed only 17% of the total dietary CP, and microbial N constituted about 50% of the NAN passing to the duodenum; this had an equalizing effect on the pattern and quantity of amino acids that passed to the duodenum. Feeding fat or different sources of protein did not alter milk production. Milk fat percentage was increased, and protein percentage was decreased when fat was fed, but yields of milk fat and protein were not different.

Effects of calcium salts of fatty acids and proportion of forage in diet on ruminal fermentation and nutrient flow to duodenum of cows.

Four Holstein cows fitted with ruminal and duodenal cannulas were used in a 4 x 4 Latin square to investigate the effects of calcium salts of long-chain fatty acids (fat) and proportion of forage in diet on ruminal fermentation, flow of nutrients to the small intestine, and animal performance. Treatments, arranged in a 2 x 2 (fat x forage) factorial, were 1) low (50%) forage, no fat; 2) low forage, fat; 3) high (67%) forage, no fat; and 4) high forage, fat. Feeding fat decreased OM intake and OM truly digested in the rumen. Feeding high forage diets decreased intakes of OM and starch and increased intakes of ADF and NDF. Ruminal pH and ratio of acetate to propionate were increased with high forage diets compared with low forage diets. Feeding fat and different amounts of forage to cows did not alter the flows of NAN and microbial N to the duodenum or efficiency of microbial growth. Production of milk and 4% FCM and percentage of fat in milk were increased by feeding fat. Feeding high forage diets decreased milk production, increased percentage of fat in milk, increased the yield of fat, and caused no change in 4% FCM production. The percentage of protein in milk was decreased by feeding high forage diets and fat, but yield of milk protein was decreased only by feeding high forage diets to cows.

Effects of urea and starch on rumen fermentation, nutrient passage to the duodenum, and performance of cows.

Four midlactation, multiparous Holstein cows fitted with ruminal and duodenal cannulas were used in a 4 x 4 Latin square design to determine the effects of supplementing urea or starch or both to diets containing fish meal on passage of nutrients to the small intestine and performance of lactating cows. The treatments (in a 2 x 2 factorial arrangement) were 1) control and control plus 2) urea, 3) starch, or 4) starch and urea. Supplementing diets with urea did not affect DMI; ruminal, postruminal, or total tract digestibilities of DM, starch, ADF, or NDF; ruminal fluid VFA concentrations or molar percentages; or ruminal fluid or particulate dilution rates. Feeding additional starch depressed DMI but did not alter ruminal or postruminal digestion of OM or VFA concentrations and molar percentages in ruminal fluid. Ruminal fluid ammonia concentration was increased by feeding urea and decreased by feeding additional starch. Passage of nonammonia N, nonammonia nonmicrobial N, or microbial N to the small intestine and efficiency of microbial CP synthesis were not affected significantly by supplying either urea or additional starch. Feeding urea increased passage of methionine to the small intestine, whereas feeding additional starch increased passage of methionine and arginine. Passage of other amino acids to the small intestine was not altered significantly by feeding urea or additional starch. Production of milk and milk protein was increased, but yields of fat and SNF were not altered by feeding diets supplemented with urea. Production of milk and milk fat was not affected, but yields of CP and SNF were decreased when additional starch was fed to cows.

Proteolysis of alcohol-treated soybean meal proteins by Bacteroides ruminicola, Bacteroides amylophilus, pepsin, trypsin, and in the rumen of steers.

Sodium dodecyl sulfate-gel electrophoresis and cation exchange chromatography were used to examine degradation of treated and untreated soybean meal protein fractions by Bacteroides amylophilus H18(1), Bacteroides ruminicola B(1)4, pepsin, trypsin, and intraruminally. Soybean meal treatments consisted of 30% vol/vol isopropanol, 40% propanol, or 50% ethanol at 22 degrees C or 70% ethanol at 80 degrees C. Water-soluble protein fractions were applied to a hydroxylapatite column and eluted with a discontinuous phosphate gradient of .03 to .27 and then .27 to 1.0 M. The four protein fractions with the highest absorbance at 276 nm were dialyzed against distilled water prior to being subjected to enzymatic hydrolysis. Soybean meal treated with 40% propanol had the greatest reduction in absorbance of all effluents at 275 nm, followed by soybean meal treated with 50% ethanol or 30% isopropanol. Comparison of electrophoretic patterns over time showed that B. amylophilus H18(1), degraded protein subunits more rapidly than B. ruminicola B(1)4. Protein subunits with the highest molecular weights were the most rapidly degraded by B. amylophilus H18(1), B. ruminicola B(1)4, pepsin, and trypsin. Hydroxylapatite chromatography of omasal fluid from steers supplemented with untreated soybean meal or soybean meal treated with 70% ethanol at 80 degrees C indicated that no detectable soluble glycinin or conglycinin escaped ruminal degradation.

Effects of ethanol and heat treatments of soybean meal and infusion of sodium chloride into the rumen on ruminal degradation and escape of soluble and total soybean meal protein in steers.

Soybean meal (SBM) treated with 70% ethanol at 80 C (ET), nontreated SBM (NT) or a ureacasein-corn mix (UC) was fed to steers fitted with ruminal and duodenal cannulae to study ruminal N metabolism. Sodium chloride (NaCl) was ruminally infused at 0 or 500 g/d. Nitrogen supplements provided approximately 70% of total dietary N. Experimental design was a 6 X 6 Latin square with a 3 X 2 factorial arrangement of treatments. Total duodenal N flows and non-ammonia, non-bacterial-N (NANB-N) flows were higher (P less than .05) when steers were fed SBM treatments compared with UC, and higher (P less than .05) when steers were fed ET compared with NT. Percentage of SBM-N escaping ruminal degradation was greater (P less than .05) when steers were fed ET compared with NT, and greater (P less than .05) when NaCl was infused into the rumen. Duodenal flows of total, indispensible and dispensible amino acids were increased (P less than .05) when steers were fed SBM treatments compared with UC, and greater (P less than .05) when steers were fed ET compared with NT. No differences in soluble N flows at the omasum were observed due to treatment. Bacterial protein comprised the majority of the N leaving the rumen. Both ruminal NaCl infusion and ethanol and heat treatment of SBM increased ruminal SBM-N escape.

Effects of heat and alcohol treatments of soybean meal on nitrogen utilization by sheep.

Soybean meal (SBM) was treated with aqueous solutions of ethanol or propanol at room temperature or at 80 C to study treatment effects on SBM-N solubility and utilization by sheep. Soybean meal was soaked in an excess of 70% (v/v) ethanol at 80 C (ET-80), 70% ethanol at 23 C (ET-23) or 70% propanol at 80 C (PR-80). Nontreated SBM and nontreated SBM heated at 80 C without alcohol treatment (NT-80) served as controls. Nitrogen solubility in McDougall's buffer was lowest (P less than .05) for PR-80 and ET-80 (2.2 and 4.7% of total N, respectively), intermediate (P less than .05) for ET-23 (9.0%), greater (P less than .05) for nontreated SBM (36.2%) and highest for NT-80 (40.2%). In an situ study using three ruminally cannulated cows and two bags per treatment per animal per removal time, more (P less than .05) N remained in in situ bags after 3, 6, 9 and 12 h incubation for ET-23, ET-80 and PR-80 than for nontreated SBM and NT-80. A lamb metabolism trial, using 15 lambs in each of two periods, compared nontreated SBM, ET-23, ET-80, PR-80 and urea as N supplements. Nitrogen retention was higher (P less than .02) for lambs fed SBM treatments compared with urea. When the same N supplements were fed to wethers in a 5 X 5 Latin square experiment and duodenal N flow was measured, non-ammonia non-bacterial N flow was higher (P less than .07) for wethers fed SBM treatments than for wethers fed urea.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of ethanol, heat, and lipid treatment of soybean meal on nitrogen utilization by ruminants.

Ruminant nitrogen utilization of soybean meal treated with 1) 70% ethanol at 23 or 78 degrees C, 2) 10% coconut oil or tallow, or 3) a combination of 70% ethanol at 78 degrees C and coconut oil or tallow was evaluated. Nitrogen solubility was lowest for soybean meal treated with ethanol at 78 degrees C, ethanol plus coconut oil and ethanol plus tallow. In situ nitrogen disappearance was lowest for soybean meal treated with ethanol at 78 degrees C, ethanol plus coconut oil, and ethanol plus tallow. Rates of nitrogen disappearance between 3 and 12 h were lowest for soybean meal treated with ethanol at 78 degrees C, ethanol plus coconut oil, and ethanol plus tallow. Nitrogen retained by lambs was greater for lambs fed soybean meal treated with ethanol at 78 degrees C than for those fed untreated soybean meal. Ruminal ammonia 4 h postfeeding was lowest for lambs fed soybean meal treated with ethanol at 78 degrees C, ethanol plus coconut oil, and coconut oil. These data indicate that the 78 degrees C ethanol treatment improved nitrogen utilization.