Evaluating glucose-based carbohydrates for use in canine diets

Extruded diets remain the most common diet format fed to dogs. Even though dogs are classified as Carnivora, carbohydrates make up 20-50% of most extruded diets. The majority of carbohydrates are in the form of starch, providing a readily available energy source. Other carbohydrate forms include dietary fiber, oligosaccharides, and resistant starches (RS) that may elicit a multitude of health benefits. Previous research has focused on the composition of traditional carbohydrate-based ingredients, but little has been done as regards the composition of various whole ingredient, fractionated ingredient, or single-source carbohydrate sources. The overall objective of this research was to evaluate glucose-based carbohydrate sources for use in canine diets, including ingredient chemical compositional analyses, effects on apparent total tract macronutrient digestibility, and effects on fecal characteristics, microbiota composition, and fermentative end-products. Our first aim was to determine the chemical composition of carbohydrate sources commonly incorporated into pet foods. We evaluated various whole grains, processed grains, grain fractions, and pseudocereal grains. Our second aim was to evaluate the effects of graded concentrations of polydextrose on apparent total tract macronutrient digestibility, fecal characteristics, fecal fermentative end-products, and fecal microbial populations in healthy adult dogs. Polydextrose was fed at 0, 0.5, 1, or 1.5% of the diet DM. Our third aim was to determine the effects of RS, naturally from whole grains, on apparent total tract macronutrient digestibility, fecal characteristics, and fecal fermentative end-products in healthy adult dogs fed a baked whole grain-containing biscuit treat. Dogs received either 0, 10, or 20 g biscuits/d (estimated to be 0, 2.5, or 5 g RS/d) that were fed within their daily caloric allowance. Our fourth aim was to determine the effects of graded concentrations of a corn-based RS source on apparent total tract macronutrient digestibility, fecal fermentative end-products, and fecal microbial populations in healthy adult dogs. Dogs were fed 0, 1, 2, 3, or 4% of diet DM of Hi-maize 260®, a corn-based ingredient that consists of 60% RS and 40% digestible starch. In our first aim, we determined that whole grains and grain fractions contain many essential nutrients including amino acids and minerals, and may provide a significant source of fiber. Because the chemical composition of grains varied greatly depending on their respective fractions (i.e., barley flake vs. malted barley vs. steamed rolled barley) and among grain type (i.e., barley flake vs. brown rice vs. canary grass seed), pet food professionals must consider both factors when formulating diets. In our second aim, we determined that polydextrose appeared to be moderately fermentable, which was evident by the increased (P<0.05) fecal SCFA concentrations, primarily acetate and propionate, and by the decrease (P<0.05) in fecal pH, without affecting food intake or fecal output. The inclusion of polydextrose also decreased (P<0.05) some protein catabolites, in particular fecal indole concentrations. Fecal C. perfringens concentrations were decreased (P<0.05) by including polydextrose in the diet, but other bacteria were unaffected. In our third aim, we determined that fat digestibility decreased (P<0.05) with whole grain treat consumption (i.e., increased RS consumption), but apparent total tract dry matter, organic matter, and crude protein digestibilities were not affected. Fecal fermentative end-products, including short- and branched-chain fatty acids, ammonia, phenols, and indoles, and microbial populations were not affected. In our fourth and final aim, we determined that dietary RS linearly decreased (P<0.05) apparent total tract dry matter, organic matter, crude protein, fat, and gross energy digestibilities, and fecal pH was linearly decreased (P < 0.05) with increased RS consumption. Fecal output was linearly increased (P < 0.05) with increased RS consumption. Fecal scores and fecal fermentative end-product concentrations, including ammonia, short-chain fatty acids, branched-chain fatty acids, phenols, and indoles were not affected by RS consumption. Predominant bacterial phyla present in all dogs included Firmicutes, Bacteroidetes, Fusobacteria, Proteobacteria, Actinobacteria, and Tenericutes. Although few bacterial taxa were altered by RS consumption, fecal Faecalibacterium were increased (P < 0.05) with increased RS consumption. This research provided a compositional database of whole ingredient, fractionated ingredient, and single-source carbohydrate sources, which may potentially impact future pet food formulations. This research provided knowledge about the use of non-digestible, glucose-based carbohydrate sources, including polydextrose, whole grain-containing RS and dietary fiber, and corn-based RS, for use in canine diets. Based on the current results, the most prominent beneficial effects were observed in healthy dogs when fed 1.5% polydextrose. However, more research is needed to determine an optimal dose of whole grains, grain fractions, or single-source RS that may elicit a beneficial response when fed to dogs

Effects of inulin or yeast cell wall extract on nutrient digestibility and fecal fermentative end-product concentrations of healthy adult dogs fed raw diets

The use of raw meat diets for pets continues to increase in popularity. Owners may choose to feed either homemade or commercially available raw meat-based diets. Raw meat-based diets often are fed because they do not contain preservatives, are highly digestible, and may improve stool quality or skin/coat quality, with many of these claims being substantiated by peer-reviewed research reports. Despite their potential benefits, raw diets also pose many potential risks. Raw meat-based diets have been shown to increase pathogen exposure, contain nutritional imbalances if not carefully formulated and monitored, and may be inconvenient for the pet owner to store or feed. Despite the proposed advantages and risks of feeding raw diets, little research has been performed to test their nutritional adequacy and safety. Due to the growing trend of pet owners choosing to feed raw meat-based diets, research on the nutrient composition and palatability of such diets, and testing their effects on stool characteristics, nutrient digestibility, fecal fermentative end-product concentrations, and fecal microbial populations is needed. The objective of this research was to determine the effects of inulin or yeast cell wall extract (YCW) on macronutrient digestibility, blood cell and metabolite concentrations, and fecal fermentative end-product concentrations in healthy adult dogs fed raw diets. Six adult female beagles (5.5 ?? 0.5 yr; 8.5 ?? 0.5 kg) were randomly allotted to the following diets using a 3 x 2 factorial in a Latin square design: 1) Beef control; 2) Beef + 1.4% inulin dry matter basis (DMB; Orafti HP, BENEO Group, Tienan, Belgium); 3) Beef + 1.4% YCW (DMB; Bio-Mos, Alltech Biotechnology, Nicholasville, KY); 4) Chicken control; 5) Chicken + 1.4% inulin (DMB); 6) Chicken + 1.4% YCW (DMB). All dogs maintained desirable stool quality characteristics, produced low stool volume, and diets were highly digestible (protein digestibility >88%; fat digestibility >97%). There were minor changes in fermentative end-product concentrations, but fecal short-chain fatty acid concentrations were increased (P<0.05) with inulin and YCW inclusion in dogs fed beef-based diets. Fecal spermine concentrations were increased (P<0.05) with inulin and YCW inclusion. In general, blood cell populations and metabolites were within the normal ranges for dogs. To evaluate the standardized amino acid digestibility of the six raw meat-based diets, a cecectomized rooster assay was conducted. Twenty-four, Single Comb White Leghorn cecectomized roosters were used in this study. Each rooster was crop-intubated and given an average of 24 g of each test diet. All excreta were collected and amino acid concentrations measured in each sample. The results of the cecectomized rooster assay indicate that the standardized amino acid digestibility was high for all diets; however, differences in amino acid digestibility existed between protein sources. The beef control diet had the lowest total essential amino acid (TEAA), total non-essential amino acid (TNEAA), and total amino acid (TAA) digestibilities (90.2, 88.7, and 85.9%, respectively) and the chicken + inulin diet had the highest TEAA, TNEAA, and TAA digestibilities (95.6, 95.2, and 92.2%, respectively). Our results agree with those from feline studies demonstrating a high nutrient digestibility of raw diets. Inulin and YCW inclusion in raw meat-based diets had similar effects on large intestinal fermentation as extruded diets containing inulin and YCW. More research is needed to confirm our data and study such diets when fed long term

Compositional Analysis of Whole Grains, Processed Grains, Grain Co-Products, and Other Carbohydrate Sources with Applicability to Pet Animal Nutrition

Our objective was to measure the proximate, starch, amino acid, and mineral compositions of grains, grain co-products, and other carbohydrate sources with potential use in pet foods. Thirty-two samples from barley (barley flake, cut barley, ground pearled barley, malted barley, whole pearled barley, pearled barley flakes, and steamed rolled barley); oats (groats, ground oatmeal, ground steamed groats, instant oats, oat bran, oat fiber, oat flour, quick oats, regular rolled oats, steamed rolled oat groats, and steel cut groats); rice (brown rice, polished rice, defatted rice bran, and rice flour); and miscellaneous carbohydrate sources (canary grass seed, hulled millet, whole millet, quinoa, organic spelt hull pellets, potato flake, sorghum, whole wheat, and whole yellow corn) were analyzed. Crude protein, amino acid, fat, dietary fiber, resistant starch, and mineral concentrations were highly variable among the respective fractions (i.e., barley flake vs. malted barley vs. steamed rolled barley) as well as among the various grains (i.e., barley flake vs. brown rice vs. canary grass seed). These ingredients not only provide a readily available energy source, but also a source of dietary fiber, resistant starch, essential amino acids, and macrominerals for pet diets

Longitudinal changes in blood metabolites, amino acid profile, and oxidative stress markers in American Foxhounds fed a nutrient-fortified diet.

The objective of the present study was to evaluate the changes in blood metabolites, AA profile, and oxidative stress markers in American Foxhound dogs fed a nutrient-fortified endurance diet while undergoing unstructured endurance exercise over several months. Thirty-six adult American Foxhound dogs (mean age: 4.5, range 2 to 10 yr and mean BW: 34.7, range: 23.1 to 46.9 kg) were selected to participate in the study. Prior to the study, all dogs consumed a commercial diet for 16 wk. After collecting baseline blood samples, dogs were assigned to a standard commercial performance diet (control) or a nutrient-fortified dog food (test). Dogs were balanced by gender, age, body weight, and athletic performance between diets. During the study, dogs underwent 78 bouts of exercise, with approximately 22 km/bout. Blood samples were collected after 40, 75, 138, and 201 d on study (October 2012 to March 2013). All blood metabolites were similar at baseline and serum chemistry profile remained within normal ranges throughout the study. Over time, plasma taurine and vitamin E concentrations decreased (P &lt; 0.05) in dogs fed the control diet but were maintained or increased (P &lt; 0.05) in dogs fed the treatment diet. Also, plasma creatinine and triglycerides were lower (P &lt; 0.05) and blood phosphorus and alkaline phosphatase were higher (P &lt; 0.05) in dogs fed the treatment diet. Vitamin E and taurine status of dogs appear to be affected by extended endurance exercise. These data suggest dogs undergoing endurance exercise may benefit from supplementation of vitamin E and taurine to minimize oxidation and maintain taurine status

In Vitro Fermentation of Xylooligosaccharides Produced from Miscanthus × <i>giganteus</i> by Human Fecal Microbiota

Purified xylooligosaccharides from Miscanthus × giganteus (M×G XOS) were used in an in vitro fermentation experiment inoculated with human fecal microbiota. A commercial XOS product and pectin were used as controls. Decreases in pH by 2.3, 2.4, and 2.0 units and production of short-chain fatty acids (SCFA; acetic acid, 7764.2, 6664.1, and 6387.9 μmol/g; propionic acid, 1006.7, 1089.5, and 661.5 μmol/g; and butyric acid, 955.5, 1252.9, and 917.7 μmol/g) were observed in M×G XOS, commercial XOS, and pectin medium after 12 h of fermentation, respectively. Titers of Bifidobacterium spp., Lactobacillus spp., and Escherichia coli increased when fed all three substrates as monitored by qPCR. There was no significant trend for Clostridium perfringens. During fermentation, M×G XOS was statistically equivalent in performance to the commercial XOS sample as measured by culture acidification and growth of health-promoting bacteria and resulted in the highest SCFA production among the three substrates

Longitudinal changes in blood metabolites, amino acid profile, and oxidative stress markers in American Foxhounds fed a nutrient-fortified diet

The objective of the present study was to evaluate the changes in blood metabolites, AA profile, and oxidative stress markers in American Foxhound dogs fed a nutrient-fortified endurance diet while undergoing unstructured endurance exercise over several months. Thirty-six adult American Foxhound dogs (mean age: 4.5, range 2 to 10 yr and mean BW: 34.7, range: 23.1 to 46.9 kg) were selected to participate in the study. Prior to the study, all dogs consumed a commercial diet for 16 wk. After collecting baseline blood samples, dogs were assigned to a standard commercial performance diet (control) or a nutrient-fortified dog food (test). Dogs were balanced by gender, age, body weight, and athletic performance between diets. During the study, dogs underwent 78 bouts of exercise, with approximately 22 km/bout. Blood samples were collected after 40, 75, 138, and 201 d on study (October 2012 to March 2013). All blood metabolites were similar at baseline and serum chemistry profile remained within normal ranges throughout the study. Over time, plasma taurine and vitamin E concentrations decreased (P &lt; 0.05) in dogs fed the control diet but were maintained or increased (P &lt; 0.05) in dogs fed the treatment diet. Also, plasma creatinine and triglycerides were lower (P &lt; 0.05) and blood phosphorus and alkaline phosphatase were higher (P &lt; 0.05) in dogs fed the treatment diet. Vitamin E and taurine status of dogs appear to be affected by extended endurance exercise. These data suggest dogs undergoing endurance exercise may benefit from supplementation of vitamin E and taurine to minimize oxidation and maintain taurine status