Article

Research Progress of Carbohydrate Nutrition in Cats and Dogs

Authors:
To read the full-text of this research, you can request a copy directly from the author.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the author.

ResearchGate has not been able to resolve any citations for this publication.
Article
Full-text available
Starch gelatinization in pet food may be affected by moisture, retention time, and ingredients used. Starch gelatinization has been associated with changes in digestibility but is not well studied using non-traditional ingredients in canine diets. The objective of this research was to examine differences in starch content and gelatinization associated with changes in ingredient profile (traditional vs. non-traditional) and nutrient content requirements associated with differing life stages. Traditional diets (n = 10) utilizing protein sources including chicken, chicken by-product meal, meat and bone meal and plant-based ingredients including rice, barley, oats, and corn were examined in comparison with non-traditional diets (n = 10) utilizing protein sources including alligator, buffalo, venison, kangaroo, squid, quail, rabbit, and salmon along with plant-based ingredients including tapioca, chickpeas, lentils, potato, and pumpkin. Total starch and gelatinized starch (as percent of total diet) were measured with variation due to ingredient type assessed using Student’s t-test in SAS 9.4. Significance was set at p < 0.05. Total starch (as a percent of diet) was higher in traditional diets compared to non-traditional diets formulated for maintenance (p < 0.0032) or all life stages (p < 0.0128). However, starch gelatinization as a proportion of total starch was lower in traditional diets formulated for maintenance (p < 0.0165) and all life stages (p < 0.0220). Total starch and gelatinized starch had a strong negative correlation (r = −0.78; p < 0.01) in diets utilizing traditional ingredients. These novel data reveal important differences between starch content and gelatinization and may impact selection of various ingredient types by pet food manufacturers.
Article
Full-text available
Hydrocolloids are commonly used in canned pet food. However, their functional effects have not been quantified in this food format. The objective was to determine the effects of select hydrocolloids on batter consistency, heat penetration, and texture of canned pet food. Treatments were added to the formula as 1% dextrose (D) and 0.5% guar gum with 0.5% of either dextrose (DG), kappa carrageenan (KCG), locust bean gum (LBG), or xanthan gum (XGG). Data were analyzed as a 1-way ANOVA with batch as a random effect and separated by Fisher’s LSD at p < 0.05. Batter consistency (distance traveled in 30 s) thickened with increasing levels of hydrocolloids (thinnest to thickest: 23.63 to 2.75 cm). The D treatment (12.08 min) accumulated greater lethality during the heating cycle compared to all others (average 9.09 min). The KCG treatment (27.00 N) was the firmest and D and DG (average 8.75 N) the softest with LBG and XGG (average 15.59 N) intermediate. Toughness was similar except D (67 N·mm) was less tough than DG (117 N·mm). The D treatment showed the greatest expressible moisture (49.91%), LBG and XGG the lowest (average 16.54%), and DG and KCG intermediate (average 25.26%). Hydrocolloids influenced heat penetration, likely due to differences in batter consistency, and affected finished product texture.
Article
Full-text available
Although dietary fiber is not considered an essential nutrient in a complete and balanced diet for felines, it provides a substrate for fermentation by gut microbiota, thus promoting gastrointestinal health through the production of fermentative metabolites, as well as improving laxation. The aim of this research was to evaluate the novel fiber source, Miscanthus grass (Miscanthus giganteus), in comparison with traditional fiber sources and their effects on fecal quality, apparent total tract digestibility (ATTD), fecal fermentative end products, and microbiota of healthy adult cats. Four dietary treatments were evaluated, differing in dietary fiber source. The diets were formulated to meet or exceed the AAFCO (2018) nutritional profile for adult cats and contained either cellulose (CO), Miscanthus grass fiber (MF), a blend of Miscanthus fiber and tomato pomace (MF + TP), or beet pulp (BP). The study was conducted using a completely randomized design with 28 neutered adult, domesticated shorthair cats (19 females and 9 males, mean age 2.2 ± 0.03 years; mean body weight 4.6 ± 0.7 kg, mean body condition score 5.6 ± 0.6). The experimental period comprised 21 days, and a fresh fecal and a total fecal collection were performed during the last 4 days of the trial period. Daily food intake (DM basis) was similar across all groups (P > 0.05). Additionally, treatment did not affect fecal output (as-is or DM basis), fecal score, or fecal pH (P > 0.05). Cats fed BP had significantly higher total dietary fiber ATTD than all the other treatments (P < 0.05) and the highest concentrations of total short-chain fatty acid, acetate, and propionate (P < 0.05), while butyrate concentrations were similar for all treatments (P > 0.05). Inclusion of dietary fibers was effective in modulating gut microbiota. Cats fed diets containing Miscanthus grass had greater α-diversity than cats fed BP. As no adverse effects on health, fecal quality, or ATTD of macronutrients were observed with the inclusion of 9% Miscanthus grass fiber or fiber blend, the data suggest that Miscanthus grass fiber and fiber blends are viable alternatives to the traditional dietary fiber sources used in commercial extruded feline diets, being most comparable to cellulose.
Article
Full-text available
Dietary digestion-resistant starch (RS) provides health benefits to the host via gut microbiome-mediated metabolism. The degree to which cats manifest beneficial changes in response to RS intake was examined. Healthy cats (N = 36) were fed identically formulated foods processed under high (n = 17) or low (n = 19) shear extrusion conditions (low and high RS levels [LRS and HRS], respectively). Fecal samples collected after 3 and 6 weeks' feeding were assayed for stool firmness score, short-chain fatty acids, ammonia, and changes to the global metabolome and microbiome; fecal immunoglobulin A (IgA) was analyzed at week 6. Few differences were seen in proximate analyses of the foods; stool firmness scores did not differ. In cats consuming HRS food, concentrations of fecal butyrate and the straight chain:branched chain fatty acid ratio were significantly greater in feces at both weeks 3 and 6, while fecal ammonia was reduced at week 6 relative to feces from LRS-fed cats. Fecal IgA concentrations were significantly higher at week 6 with HRS food. RS consumption altered 47% of the fecal metabolome; RS-derived sugars and metabolites associated with greater gut health, including indoles and polyamines, increased in the cats consuming HRS food relative to those fed the LS food, while endocannabinoid N-acylethanolamines decreased. Consumption of HRS food increased concentrations of the ketone body 3-hydroxybutyrate in feces and elevated concentrations of reduced members of NADH-coupled redox congeners and NADH precursors. At the microbiome genus-level, 21% of operational taxonomic units were significantly different between food types; many involved taxa with known saccharolytic or proteolytic proclivities. Microbiome taxa richness and Shannon and Simpson alpha diversity were significantly higher in the HRS group at both weeks. These data show that feline consumption of grain-derived RS produces potentially beneficial shifts in microbiota-mediated metabolism and increases IgA production.
Article
Full-text available
Starches provide an effective energy source for dogs and cats and can affect health according to its inclusion and extent of digestion. The starch fraction that escapes small intestine (SI) digestion is called resistant starch (RS) and is desirable due to its prebiotic function. Starch is not an essential nutrient for dogs and cats and thus is not reported on commercial pet food labels. Hence, the objective of this work was to characterize starches in commercial pet foods. The top five pet food companies by sales were selected to represent US pet foods, which were divided into four strata with a sampling frame of 654 foods: dog grain based (372 foods), dog grain free (71 foods), cat grain based (175 foods), and cat grain free (38 foods). Five random foods within each stratum were purchased (20 total). Starch analyses (total starch, resistant starch and starch cook), as well as nutrient analyses were conducted on all foods. Total starch, RS and starch cook means were compared using a 2-group Z-test on dog vs cat and grain-based vs grain-free diets, and differences were considered significant at a P < 0.05. Total starch was higher (P < 0.05) in dog than cat food, and starch cook was greater (P < 0.05) in grain-free diets. A regression analysis showed that NFE was a good predictor of total starch. Resistant starch was low and not different among groups. A post-hoc test showed that a total sample size of at least 28 diets per group would be required to detect differences in RS between GF and GB diets, if one exists.
Article
Full-text available
Type, quality, and origin of cereals in diets of poultry and pigs could influence gut microbes and affect their diversity and function, thereby impacting the intestinal function of the monogastric animal. In this review, we focus on the major carbohydrates in cereals that interact directly with gut microbes and lead to the production of key metabolites such as short-chain fatty acids (SCFA), and discuss how cereal fiber impact intestinal health of poultry and pigs. An overview of how the cereals and cereals-derived carbohydrates such as beta-glucans, resistant starch, cellulose, and arabinoxylans could promote intestinal health and reduce the use of in-feed antibiotics in animal production are presented. The metabolic pathway utilized by microbes and the mechanism of action underlying the produced SCFA on intestinal health of monogastric animals is also discussed. Keywords: Arabinoxylans, Beta-glucans, Resistant starch, Cellulose, SCFA, Intestinal health
Article
Full-text available
Background Starch is the main source of energy in commonly used pig diets. Besides effects related to the extent of starch digestion, also several effects related to variation in digestion rate have recently been demonstrated in non-ruminants. Different rates of starch digestion in animals and in in vitro models have been reported, depending on the botanic origin of starch. Starches from different botanic sources differ widely in structural and molecular properties. Predicting the effect of starch properties on in vitro digestion kinetics based on existing literature is hampered by incomplete characterization of the starches, or by a selective choice of starches from a limited number of botanic sources. This research aimed to analyse the relationships between starch properties and in vitro digestion kinetics of pure starches isolated from a broad range of botanic origins, which are used in non-ruminant diets or have a potential to be used in the future. Therefore we studied starch digestion kinetics of potato, pea, corn, rice, barley, and wheat starches, and analysed the granule diameter, number of pores, type and amount of crystalline structure, amylose content and amylopectin side-chain length of all starches. Results Multivariate analysis revealed strong correlations among starch properties, leading us to conclude that effects of most starch characteristics are strongly interrelated. Across all analysed botanic sources, crystalline type and amylopectin chain length showed the strongest correlation with in vitro digestion kinetics. Increased percentages of A–type crystalline structure and amylopectin side chains of DP 6–24 both increased the rate of digestion. In addition, within, but not across, (clusters of) botanic sources, a decrease in amylose content and increase in number of pores correlated positively with digestion kinetics. Conclusion The type of crystalline structure and amylopectin chain length distribution of starch correlate significantly with digestion kinetics of starches across botanic sources in an in vitro pig model. Variation in digestion kinetics across botanic sources is not additively explained by other starch properties measured, but appears to be confined within botanical sources. Electronic supplementary material The online version of this article (10.1186/s40104-018-0303-8) contains supplementary material, which is available to authorized users.
Article
Full-text available
Prebiotic dietary fibers act as carbon sources for primary and secondary fermentation pathways in the colon, and support digestive health in many ways. Fructooligosaccharides, inulin, and galactooligosaccharides are universally agreed-upon prebiotics. The objective of this paper is to summarize the 8 most prominent health benefits of prebiotic dietary fibers that are due to their fermentability by colonic microbiota, as well as summarize the 8 categories of prebiotic dietary fibers that support these health benefits. Although not all categories exhibit similar effects in human studies, all of these categories promote digestive health due to their fermentability. Scientific and regulatory definitions of prebiotics differ greatly, although health benefits of these compounds are uniformly agreed upon to be due to their fermentability by gut microbiota. Scientific evidence suggests that 8 categories of compounds all exhibit health benefits related to their metabolism by colonic taxa.
Article
Full-text available
Gastrointestinal transit time may be an important determinant of glucose homeostasis and metabolic health through effects on nutrient absorption and microbial composition, among other mechanisms. Modulation of gastrointestinal transit may be one of the mechanisms underlying the beneficial health effects of dietary fibers. These effects include improved glucose homeostasis and a reduced risk of developing metabolic diseases such as obesity and type 2 diabetes mellitus. In this review, we first discuss the regulation of gastric emptying rate, small intestinal transit and colonic transit as well as their relation to glucose homeostasis and metabolic health. Subsequently, we briefly address the reported health effects of different dietary fibers and discuss to what extent the fiber-induced health benefits may be mediated through modulation of gastrointestinal transit.
Article
Full-text available
This qualitative study explores a widespread contemporary family form, the interspecies family, to understand how people who count their cats and dogs as family members describe this process of becoming and maintaining family. We focus on one aspect of interspecies families—pet parenting. We find that even though individuals say their pets are family, not all consider themselves to be parents or engaged in pet parenting. Participants with human children differed somewhat from those without human children, suggesting that family form shapes pet parenting experiences. Childless participants draw heavily from larger cultural narratives surrounding parenting to construct the parent–pet child relationship. Those with younger human children talk about the relationship primarily from a place of difference, while those with older human children construct the relationship in similar ways to childless individuals and emphasize similarities between raising children and pets. This study contributes to the literature on family change and human–animal relationships within households.
Article
Full-text available
The domestic cat’s wild ancestors are obligate carnivores that consume prey containing only minimal amounts of carbohydrates. Evolutionary events adapted the cat’s metabolism and physiology to this diet strictly composed of animal tissues and led to unique digestive and metabolic peculiarities of carbohydrate metabolism. The domestic cat still closely resembles its wild ancestor. Although the carnivore connection of domestic cats is well recognised, little is known about the precise nutrient profile to which the digestive physiology and metabolism of the cat have adapted throughout evolution. Moreover, studies show that domestic cats balance macronutrient intake by selecting low-carbohydrate foods. The fact that cats evolved consuming low-carbohydrate prey has led to speculations that high-carbohydrate diets could be detrimental for a cat’s health. More specifically, it has been suggested that excess carbohydrates could lead to feline obesity and diabetes mellitus. Additionally, the chances for remission of diabetes mellitus are higher in cats that consume a low-carbohydrate diet. This literature review will summarise current carbohydrate knowledge pertaining to digestion, absorption and metabolism of carbohydrates, food selection and macronutrient balancing in healthy, obese and diabetic cats, as well as the role of carbohydrates in prevention and treatment of obesity and diabetes mellitus.
Article
Full-text available
Recent studies of the mechanisms determining the rate and extent of starch digestion by α-amylase are reviewed in the light of current widely-used classifications for (a) the proportions of rapidly-digestible (RDS), slowly-digestible (SDS), and resistant starch (RS) based on in vitro digestibility, and (b) the types of resistant starch (RS 1,2,3,4…) based on physical and/or chemical form. Based on methodological advances and new mechanistic insights, it is proposed that both classification systems should be modified. Kinetic analysis of digestion profiles provides a robust set of parameters that should replace the classification of starch as a combination of RDS, SDS, and RS from a single enzyme digestion experiment. This should involve determination of the minimum number of kinetic processes needed to describe the full digestion profile, together with the proportion of starch involved in each process, and the kinetic properties of each process. The current classification of resistant starch types as RS1,2,3,4 should be replaced by one which recognises the essential kinetic nature of RS (enzyme digestion rate vs small intestinal passage rate), and that there are two fundamental origins for resistance based on (i) rate-determining access/binding of enzyme to substrate and (ii) rate-determining conversion of substrate to product once bound.
Article
Full-text available
The objective of this work was to study nutritional strategies for decreasing methane production by ruminants fed tropical diets, combining in vitro and in vivo methods. The in vitro approach was used to evaluate the dose effect of condensed tannins (CT) contained in leaves of Glyricidia sepium, Leucaena leucocephala, and Manihot esculenta (39, 75 and 92 g CT/kg DM, respectively) on methane production and ruminal fermentation characteristics. Tannin-rich plants (TRP) were incubated for 24 h alone or mixed with a natural grassland hay based on Dichanthium spp. (control plant), so that proportions of TRP were 0, 0.25, 0.5, 0.75, and 1.0. Methane production, VFA concentration and fermented organic matter decreased with increased proportions of TRP. Numerical differences on methane procduction and VFA concentration among TRPTRP sources may be due to differences in their CT content, with greater effects for L. leucocephala and M. esculenta than for G. sepium. Independently of TRP, the response to increasing doses of CT was linear for methane production but quadratic for VFA concentration. As a result, at moderate tannin dose, methane decreased more than VFA. The in vivo trial was conducted to investigate the effect of tannin-rich plants on different ruminal microbial populations. To this end, eight rumen-cannulated sheep from two breeds (Texel and Blackbelly) were used in two 4 × 4 Latin square designs. Diets were fed ad libitum and were composed of the same feeds used for the in vitro trial: control plant alone or combined with pellets made from TRP leaves at 44% of the diet DM. Compared to TRP, concentration of Ruminococcus flavefaciens was greater for the control diet and concentration of Ruminococcus albus was least for the control diet. The methanogen population was greater for Texel than for Blackbelly. By contrast, TRP containing diets did not affect protozoa or Fibrobacter succinogenes numbers. Hence TRP showed potential for mitigating methane production by ruminants. These findings suggest that tannin-rich plants fed as pellets could be used to decrease methane production.
Article
Full-text available
The US has a pet population of approximately 70 million dogs and 74 million cats. Humans have developed a strong emotional bond with companion animals. As a consequence, pet owners seek ways to improve health, quality of life and longevity of their pets. Advances in canine and feline nutrition have contributed to improved longevity and well-being. Dietary fibers have gained renewed interest in the pet food industry, due to their important role in affecting laxation and stool quality. More recently, because of increased awareness of the beneficial effects of dietary fibers in health, as well as the popularity of functional foods and holistic and natural diets, alternative and novel carbohydrates have become widespread in human and pet nutrition. Fiber sources from cereal grains, whole grains and fruits have received increasing attention by the pet food industry and pet owners. While limited scientific information is available on the nutritional and nutraceutical properties of alternative fiber sources, studies indicate that corn fiber is an efficacious fiber source for pets, showing no detrimental effects on palatability or nutrient digestibility, while lowering the glycemic response in adult dogs. Fruit fiber and pomaces have good water-binding properties, which may be advantageous in wet pet food production, where a greater water content is required, along with low water activity and a firm texture of the final product. Rice bran is a palatable fiber source for dogs and may be an economical alternative to prebiotic supplementation of pet foods. However, it increases the dietary requirement of taurine in cats. Barley up to 40% in a dry extruded diet is well tolerated by adult dogs. In addition, consumption of complex carbohydrates has shown a protective effect on cardiovascular disease and oxidative stress. Alternative fiber sources are suitable ingredients for pet foods. They have been shown to be nutritionally adequate and to have potential nutraceutical properties.
Article
Full-text available
In dry-extruded canine diets, starch ileal digestibility varies with the starch source, amount and processing parameters. Starch that escapes duodeno-ileal digestion can affect faecal quality by stimulating colonic bacterial fermentation. The aim of the present study was to assess the effect of various resistant starch (RS) sources and levels on the faecal score of dogs of different breeds and sizes. A total of twenty-one healthy adult female dogs (body weight ranging 5.0-30.6 kg) were used. The maintenance diet for the dogs was supplemented with increasing amounts of RS from two sources: high-amylose starch from maize (to 2.5, 4.3 and 7.4 % RS) and raw potato starch (to 7.4 and 11.4 % RS). Each level of RS was tested over a 7 d period followed by a 7 d washout period. Faecal scores were evaluated by one person using a scale ranging from 1 (for hard and dry faeces) to 5 (for liquid stools). Faeces were considered 'optimal' at scores of 2.5-3.0, 'acceptable' at scores of 3.0-3.75 and 'unacceptable' at scores >3.75. Small dogs showed very little sensitivity to RS based on the faecal score, while large dogs were quite responsive to RS supplementation. These results suggest that small dogs are poor models for assessing the effect of starch sources on ileal digestibility. They also indicate that a low RS content (strongly affected by source and processing) is an important factor for ensuring an optimal faecal score in large breed dogs.
Article
Full-text available
Beagle bitches, obtained 3 weeks post-conception, were fed one of two diets; diet 1 contained 44% of metabolizable energy from carbohydrate and diet 2 contained 0% of metabolizable energy from carbohydrate. Bitches consumed similar amounts of energy from the two diets. Plasma glucose levels were similar in bitches fed the two diets, except in the week before whelping. At this time, plasma glucose levels as low as 15--20 mg/dl were observed in several bitches fed diet 2. None of the bitches fed diet 1 exhibited hypoglycemia. Bitches fed diet 2 also had depressed plasma levels of alanine and lactate and elevated levels of free fatty acids and B-hydroxybutyrate near the end of gestation. Total number of pups whelped by the bitches was unaffected by diet, but fewer pups from bitches fed diet 2 were alive at birth (63%) than from bitches fed diet 1 (96%). Only 35% of the pups whelped by bitches fed diet 2 were alive at 3 days of age. Milk from bitches fed diet 2 had a lower percentage of energy from lactose and a higher percentage of energy from fat than did milk of bitches fed diet 1. Growth of pups, however, was unaffected by composition of diet fed to the bitches. We concluded that pregnant bitches require dietary carbohydrate for optimal reproductive performance.
Article
Full-text available
Two in vitro experiments were conducted to evaluate the ability of small intestinal bacteria of dogs to ferment native and extruded cereal grains and potato starch and cereal grain and potato flours. Substrates included barley, corn, potato, rice, sorghum, and wheat. In addition to testing native grains and flours, extruded substrates also were tested. Substrates were extruded at low temperatures (LT; 79 to 93 degrees C) and high temperatures (HT; 124 to 140 degrees C) using a Wenger extruder (model TX-52). Substrates varied widely in concentrations of rapidly digestible starch (RDS), slowly digestible starch (SDS), resistant starch (RS), and total starch (TS). Extrusion of most substrates at HT vs LT resulted in increased RDS and decreased RS concentrations. Organic matter disappearance (OMD) values attributed to microbial fermentation for a 5-h period were as high as 27% for native extruded substrates (LT potato starch) and 39% for potato flour. Average OMD was higher for cereal and potato flours than for native extruded substrates (29.9 vs 25.4%). Average molar percentages of short-chain fatty acids produced from all substrates fermented for 5 h were 73, 14, and 13% (acetate, propionate, and butyrate, respectively). Average lactate production for substrates ranked as follows: flours > native and extruded cereal grains and potato starch (0.33 and 0.18 mmol/g OM, respectively). In vitro microbial fermentation of starches by ileal bacteria can be substantial and is affected by differences in starch source, fraction, and processed form.
Article
Full-text available
Companion animal diets may contain up to 50% starch, derived from cereal grains. The amount of resistant starch (RS) in an ingredient depends on the origin and form of the ingredient and on the processing conditions to which the ingredient has been exposed. Extrusion has proven to be a means of optimizing utilization of starch by companion animals. Although the RS fraction of starch typically decreases by extrusion, retrogradation can result in increased concentrations of this fraction. Limited research exists regarding the effects of RS in companion animal nutrition and gastrointestinal health. Existing in vitro and in vivo research indicates that certain RS sources are readily fermented in the large bowel, producing short-chain fatty acids, whereas others are less fermentable, resulting in excellent laxation properties. Feeding dogs a diet high in RS may result in an increase in fecal bulk due to an increased excretion of microbial matter in those cases where RS is highly fermentable, or to indigestibility of the RS source in other cases. RS has a role to play as a potential proxy for dietary fiber, especially for those companion animals fed diets high in protein and fat and devoid of traditional dietary fiber.
Article
Full-text available
This study compared the effects of a moderate carbohydrate-high fiber (MC-HF) food and a low carbohydrate-low fiber (LC-LF) food on glycemic control in cats with diabetes mellitus. Sixty-three diabetic cats (48 male castrated, 15 female spayed) were randomly assigned to be fed either a canned MC-HF (n = 32) food or a canned LC-LF (n = 31) food for 16 weeks. Owners were blinded to the type of diet fed. CBC, urinalysis, serum chemistry panel, fructosamine concentration and thyroxine concentration were determined on initial examination, and a complete blood count, serum chemistry panel, urinalysis and serum fructosamine concentration were repeated every 4 weeks for 16 weeks. Insulin doses were adjusted as needed to resolve clinical signs and lower serum fructosamine concentrations. Serum glucose (P = 0.0001) and fructosamine (P = 0.0001) concentrations significantly decreased from week 0 to week 16 in both dietary groups. By week 16, significantly more of the cats fed the LC-LF food (68%, 22/31), compared to the cats fed the MC-HF food (41%, 13/32), had reverted to a non-insulin-dependent state (P = 0.03). Cats in both groups were successfully taken off of insulin regardless of age, sex, type of insulin administered or duration of clinical disease before entering the study. There was no significant difference in the initial or final mean body weights or in the mean change in body weight from week 0 to week 16 between dietary groups. Diabetic cats in this study were significantly more likely to revert to a non-insulin-dependent state when fed the canned LC-LF food versus the MC-HF food.
Article
Full-text available
Dietary carbohydrates are a group of chemically defined substances with a range of physical and physiological properties and health benefits. As with other macronutrients, the primary classification of dietary carbohydrate is based on chemistry, that is character of individual monomers, degree of polymerization (DP) and type of linkage (alpha or beta), as agreed at the Food and Agriculture Organization/World Health Organization Expert Consultation in 1997. This divides carbohydrates into three main groups, sugars (DP 1-2), oligosaccharides (short-chain carbohydrates) (DP 3-9) and polysaccharides (DP> or =10). Within this classification, a number of terms are used such as mono- and disaccharides, polyols, oligosaccharides, starch, modified starch, non-starch polysaccharides, total carbohydrate, sugars, etc. While effects of carbohydrates are ultimately related to their primary chemistry, they are modified by their physical properties. These include water solubility, hydration, gel formation, crystalline state, association with other molecules such as protein, lipid and divalent cations and aggregation into complex structures in cell walls and other specialized plant tissues. A classification based on chemistry is essential for a system of measurement, predication of properties and estimation of intakes, but does not allow a simple translation into nutritional effects since each class of carbohydrate has overlapping physiological properties and effects on health. This dichotomy has led to the use of a number of terms to describe carbohydrate in foods, for example intrinsic and extrinsic sugars, prebiotic, resistant starch, dietary fibre, available and unavailable carbohydrate, complex carbohydrate, glycaemic and whole grain. This paper reviews these terms and suggests that some are more useful than others. A clearer understanding of what is meant by any particular word used to describe carbohydrate is essential to progress in translating the growing knowledge of the physiological properties of carbohydrate into public health messages.
Article
Dietary fiber describes a diverse assortment of nondigestible carbohydrates that play a vital role in the health of animals and maintenance of gastrointestinal tract homeostasis. The main roles dietary fiber play in the gastrointestinal tract include physically altering the digesta, modulating appetite and satiety, regulating digestion, and acting as a microbial energy source through fermentation. These functions can have widespread systemic effects. Fiber is a vital component of nearly all commercial canine and feline diets. Key features of fiber types, such as fermentability, solubility, and viscosity, have been shown to have clinical implications as well as health benefits in dogs and cats. Practitioners should know how to evaluate a diet for fiber content and the current knowledge on fiber supplementation as it relates to common enteropathies including acute diarrhea, chronic diarrhea, constipation, and hairball management. Understanding the fundamentals of dietary fiber allows the practicing clinician to use fiber optimally as a management modality.
Article
This study assessed the effects of a diet containing avocado meal (AMD), an underutilized by-product avocado oil processing, on apparent total tract digestibility (ATTD) and fecal fermentative end-products when compared with beet pulp (BPD) and cellulose (CD) diets targeting 15% total dietary fiber (TDF). The concentration of persin, a natural fungicidal toxin present in avocado, was also determined on several parts of the fruit and avocado meal. Nine intact female beagles (4.9 ± 0.6 yr and 11.98 ± 1.76 kg) were randomly grouped in a 3 × 3 replicated Latin square design. Periods were 14 d long, with 10 d of adaptation followed by 4 d of total fecal and urine collection for apparent total tract digestibility (ATTD) calculations. Fresh fecals were analyzed for fermentative end-products. The BPD (87.0 g/d) caused higher (P < 0.05) fecal output (as-is basis) than AMD (62.3 g/d) and CD (58.0 g/d). Fecal score for the BPD (3.1) was greater (P < 0.05) than for AMD (2.8) or CD (2.6). Acid-hydrolyzed fat ATTD was lower (P < 0.05) for the BPD (94.1%) than for the AMD (95.5%) and CD (95.7%). Crude protein ATTD was greater (P < 0.05) for the CD (88.5%) than the AMD (82.2%) or BPD (83.7%). Dogs fed AMD (49.9%) or BPD (51.0%) exhibited greater (P < 0.05) TDF ATTD than CD. The fermentative profile for the AMD (233.4, 70.9, 8.8, and 12.0 μmole/g DM, respectively) was similar (P > 0.05) to the CD (132.9, 61.7, 7.5, and 9.5 μmole/g DM, respectively) profile, with lower (P < 0.05) concentrations of acetate and propionate and higher (P < 0.05) concentrations of isovalerate and indoles compared to the BPD. Dogs fed AMD (47.0 μmole/g DM) or BPD (54.2 μmole/g DM) exhibited similar (P > 0.05) fecal butyrate concentrations greater (P < 0.05) than for CD (24.7 μmole/g DM). Given these results, avocado meal appears to be an adequate dietary fiber source when compared with traditional fiber sources used in canine diets. No health adverse effects were observed in dogs fed extruded diet containing as much as 18% of avocado meal (as-is basis).
Chapter
Although carbohydrates and sugars are not considered indispensable dietary nutrients for fish or shrimp, they contribute in a significant manner as a source of digestible energy. This chapter addresses different aspects of the issues related with inclusion and utilization of dietary carbohydrates by aquatic animals. Raw complex carbohydrates are poorly digested by many species of fish, but utilization can be significantly improved by appropriate technological treatments of the feedstuffs or the feeds themselves. Utilization of absorbed glucose is known to differ from that in terrestrial vertebrates and to vary between species of fish. Much progress has been made over the past decades to obtain insights on various aspects of glucose metabolism and homeostasis. Identifying the fine balance between endogenous glucose production and glucose utilization in different species of farmed fish and shrimp is a challenging and promising area of research and can provide the basis for taking full benefit of the potential of all sources of digestible carbohydrates.
Article
Beet pulp (BP) and cellulose (CE) are fibrous ingredients commonly used by pet food companies to produce diets targeting weight management and gut health. Miscanthus grass (MG) is a novel fibrous ingredient that might affect food manufacturing in a similar manner to CE. The objective was to determine the effects of these three fiber sources on extrusion processing and kibble characteristics of dog foods. Diets were composed of 90% basal ration and 10% of each MG (827.4 g/kg insoluble fiber, 72.6 g/kg soluble fiber), CE (1000 g/kg insoluble fiber), or BP (360.0 g/kg insoluble fiber, 263.7 g/kg soluble fiber). Three batches of each treatment were mixed separately prior to extrusion. During production, processing conditions were recorded every 20 min after steady state was achieved. At each time point, 10 kibbles were randomly sampled to measure diameter and length out of the extruder and exiting the dryer. Sectional expansion ratio index (SEI) was calculated using the die and kibble diameter. Diet total dietary fiber (TDF) was similar among treatments (MG = 199.7 g/kg, CE = 204.7 g/kg, BP = 175.9 g/kg). The fiber source did not affect preconditioner and extruder parameters, except specific mechanical energy (SME), in which BP was higher than MG and CE (P<0.05; 111.8 vs. 108.9 and 108.7 W h/kg, respectively). Additionally, kibble from the BP diet had larger diameter and SEI than MG and CE (P<0.05). Kibbles from the BP diet tended (P>0.10) to have greater volume than MG kibbles. MG kibbles had a smaller volume than CE and BP kibbles. CE kibbles were less dense than BP kibbles. These results indicate that a diet containing MG can be processed with similar conditions to a diet containing CE. In conclusion, the extrusion parameters were minimally affected by fiber source, and differences in kibble characteristics could be corrected with modest process adjustments.
Article
Resistant starch (RS) is fermentable by gut microbiota and effectively modulates fecal short-chain fatty acid concentrations in pigs, mice, and humans. RS may have similar beneficial effects on the canine gut, but has not been well studied. The objective of this study was to evaluate the effects of 0, 1, 2, 3, and 4% dietary RS (Hi-maize 260) on apparent total tract macronutrient digestibility, and fecal characteristics, fermentative end-product concentrations, and microbiota of healthy adult dogs. An incomplete 5 x 5 Latin square design with 7 dogs and 5 experimental periods was used, with each treatment period lasting 21 d (d 0-17 adaptation; d 18-21 fresh and total fecal collection) and each dog serving as its own control. Seven dogs (mean age = 5.3 yr; mean BW = 20 kg) were randomly allotted to one of five treatments formulated to be iso-energetic and consisting of graded amounts of 100% amylopectin cornstarch, RS, and cellulose, and fed as a top dressing on the food each day. All dogs were fed the same amount of a basal diet throughout the study and fresh water was offered ad libitum. The basal diet contained 6.25% RS (DM basis), contributing approximately 18.3 g of RS/d based on their daily food intake (292.5 g DM/d). Data were evaluated for linear and quadratic effects using SAS. The treatments included 0%, 1%, 2%, 3%, and 4% of an additional RS source. Because Hi-maize 260 is approximately 40% digestible and 60% indigestible starch, the dogs received the following amounts of RS daily: 0% = 18.3 g (18.3 g + 0 g); 1% = 20.1 g (18.3 g + 1.8 g); 2% = 21.9 g (18.3 g + 3.6 g); 3% = 23.7 g (18.3 g + 5.4 g); and 4% = 25.5 g (18.3 g + 7.2 g). Apparent total tract dry matter, organic matter, crude protein, fat, and gross energy digestibilities and fecal pH were 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 were not affected by RS consumption. Although most fecal microbial taxa were not altered, Faecalibacterium were increased (P < 0.05) with increased RS consumption. The decrease in fecal pH and increase in fecal Faecalibacterium would be viewed as being beneficial to gastrointestinal health. Although our results seem to indicate that RS is poorly and/or slowly fermentable in dogs, the lack of observed change may have been due to the rather high level of RS contained in the basal diet.
Article
This study adapted the established glycemic index (GI) methodology used in human research to perform two studies in sled dogs in order to assess the blood glucose raising potential of pulse-based dog foods. The first was a pilot study (n=6 dogs) to determine the GI of single starch sources (white bread, cooked white rice and cooked green lentils) using a glucose solution as control. Next, the effect on glycemic and insulinemic meal responses and GI of commercial extruded dog foods containing different categories of starch sources (traditional grain, whole grain, grain-free and vegan) were investigated on n=11 dogs using a glucose control. Results were compared using repeated measures ANOVA. Consumption of 10 g of available carbohydrate (Av CHO) was insufficient to elicit a measurable response in blood glucose for GI determination, and as such, the amount was increased to 25 g for the second study. The glycemic index (±SE) of the single starch sources and dog foods were: white bread 47 ± 11; cooked white rice 71 ± 14; cooked green lentils 60 ± 20 (p = 0.569); traditional grain 83 ± 17; whole grain 56 ± 8; grain-free 41± 6; and vegan 65 ± 15 (p = 0.154) . No statistical differences in glycemic response over time were observed between the single starch sources or the extruded diets tested (p =0.1412; p =0.2651). Insulinemic response elicited by the extruded diets was also not different (p = 0.079); however the traditional grain diet did have the slowest time to peak for insulin (p = 0.0078). Among single starch sources and extruded dog foods, there were no differences in the glycemic indices measured in this study. The GI methodology has not been validated for use in canine species and it is likely that our results were due to higher inter-individual variation or inadequate study power. Regardless, this study will serve to better define future studies to investigate the potential physiological benefits of low glycemic index foods for dogs.
Article
The aim of this study was to evaluate the impact of ancient grain and grain free carbohydrate sources on extrusion process, nutrient utilization, and palatability by dogs. Two maintenance dog diets were formulated with same proportions of carbohydrates: 1) Ancient grain diet (AG) with spelt, millet and sorghum; and 2) Grain free diet (GF) which had potato, peas and tapioca starch. Experimental diets were extruded over five replicates in a completely randomized experimental design. Digestibility was carried out with twelve dogs in a switch back experimental design. The GF diet required 22.6% and 25.9% more (P < 0.05) specific mechanical energy and in-barrel moisture input, respectively, than AG to produce kibbles out of the extruder with similar bulk density (P > 0.05). After drying, GF kibbles were less dense and more expanded, but harder than AG kibbles (P< 0.05). Dogs preferred GF over AG in the palatability assessment of uncoated kibbles. Apparent nutrient digestibility of dry matter, organic matter, gross energy, crude protein, and crude fat were not affected by treatment (P > 0.05). However, total dietary fiber (TDF) digestibility was 31.9% greater for dogs fed GF (P < 0.05). Moreover, wet fecal output was higher, and fecal dry matter was lower for dogs under GF (P < 0.05). The results demonstrated that GF and AG diets behaved differently during extrusion, but were similarly utilized by dogs, with exception of TDF. Thus, fiber content of grain-free diets should be monitored to maximize fecal quality.
Article
Hypogylcemia in dogs is defined as a blood glucose concentration of less than 3.3 mmol/L (60 mg/dL) and is a relatively common problem encountered in veterinary practice. This metabolic disorder can have an array of clinical signs, ranging from subtle abnormalities to a life-threatening emergency. Hypoglycemia can be due to several physiological processes or etiologies. It is imperative that the clinician is astute in diagnosing hypoglycemia, proficient in providing rapid symptomatic treatment (if indicated) and has a clear diagnostic plan to elucidate the underlying cause. This article reviews the pathophysiology, most common etiologies, and emergency management of hypoglycemia, and presents a diagnostic approach for this problem.
Article
The Food and Drug Administration (FDA or we) is amending its labeling regulations for conventional foods and dietary supplements to provide updated nutrition information on the label to assist consumers in maintaining healthy dietary practices. The updated information is consistent with current data on the associations between nutrients and chronic diseases, health-related conditions, physiological endpoints, and/or maintaining a healthy dietary pattern that reflects current public health conditions in the United States, and corresponds to new information on consumer understanding and consumption patterns. The final rule updates the list of nutrients that are required or permitted to be declared; provides updated Daily Reference Values and Reference Daily Intake values that are based on current dietary recommendations from consensus reports; amends requirements for foods represented or purported to be specifically for children under the age of 4 years and pregnant and lactating women and establishes nutrient reference values specifically for these population subgroups; and revises the format and appearance of the Nutrition Facts label.
Article
In last few decades, indigestible carbohydrates as dietary fiber have attracted interest of food scientists and technologists due to its several physiological benefits. Dietary fibers are generally of two types based on their solubility i.e. soluble and insoluble dietary fiber. Significant physicochemical properties of dietary fiber include solubility, viscosity, water holding capacity, bulking and fermentability. Some important dietary fibers are celluloses, hemicelluloses, hydrocolloids, resistant starches and non digestible oligosaccharides. Inclusion of these fibers in daily diet imparts several health benefits such as prevention or reduction of bowel disorders, and decrease risk of coronary heart disease and type 2 diabetes.
Article
Kohlenhydmtstoffwechsel der Katze. 4. Maltase-, Isomaltase-, Saccharase- und Lactaseaktivität im Verdauungskanal in Abhängigkeit von Alter und Fütteung Bei 26 erwachsenen Europäisch-Kurzhaarkatzen und 32 Katzenwelpen (neugeboren bis 12 Wochen alt) wurde die Aktivität der Maltase, Isomaltase, Saccharase und Lactase in der Dünndarmmucosa überprüft. Bei einem Teil der adulten Tiere wurde außerdem die Aktivität im Pancreasgewebe, in der Dickdarmmucosa, im Chymus und in den Faeces untersucht. Die Bestimmung der Disaccharidaseaktivität erfolgte durch Freisetzung von Glucose aus Disacchariden, als Bezugssystem wurde der Proteingehalt der Mucosa herangezogen. Die Fütterung (kohlenhydratfrei, stärkereich mit 29–37% Stärke, saccharosereich mit 36% Saccharose, lactosereich mit 28% Lactose in der Trockensubstanz) hatte keinen Einfluß auf die Aktivität der Disaccharidasen. Maltase, Isomaltase und Saccharase wurden auch vom Alter nicht beeinflußt (Maltase adult 102 ± 58, neugeboren 66 ± 77, Isomaltase 35 ± 28 bzw. 30 ± 20, Saccharase 17 ± 23 bei adulten und 15 ± 8 U/g Protein bei neugeborenen Katzen). Dagegen ging die Lactaseaktivität von 96 + 66 U/g Protein bei neugeborenen Katzen auf 13 ± 9 U/g Protein bei 6 Wochen alten Welpen zurück (adulte 7 ± 8). Bei einzelnen adulten Tieren trat im Jejunum eine weit überdurchschnittliche Lactaseaktivität (bis zu 53 U/g Protein) auf. Im Pancreasgewebe wurde eine geringe Maltase- und Isomaltaseaktivität aber weder Lactase noch Saccharase, nachgewiesen. In Chymus und Feces waren alle überprüften Disaccharidase (Maltase, Saccharase, Lactase) in geringer Aktivität vorhanden, in der Dickdarmmucosa lag sie in ähnlicher Größenordnung wie im Chymus.
Article
Comparative effects of extrusion cooking and conventional processing methods on protein content and reduction of antinutritional factor (phytic acid, condensed tannins, polyphenols, trypsin, chymotrypsin, α-amylase inhibitors and haemagglutinating activity) levels in Vicia faba and Phaseolus vulgaris seeds were studied. In vitro protein and starch digestibilities were assessed. P. vulgaris seeds showed highest levels of condensed tannins, chymotrypsin and α-amylase inhibitory activities and haemagglutinating activity. Dehulling significantly increased protein content and greatly reduced condensed tannin and polyphenol levels in both legumes. Extrusion was the best method to abolish trypsin, chymotrypsin, α-amylase inhibitors and haemagglutinating activity without modifying protein content. Furthermore, this thermal treatment was most effective in improving protein and starch digestibilities when compared with dehulling, soaking and germination.
Article
Every clinician is asked "What should I feed my pet?" Understanding the ingredients in pet food is an important part of making the best recommendation. Pet food can be as simple as one ingredient or as complicated as containing more than 60 ingredients. Pet food and its ingredients are regulated by the Food and Drug Administration and state feed officials. Part of that regulation is the review and definition of ingredients. Existing ingredients change and new ingredients become available so the need for ingredient definitions grows. Ingredients for product formulations are chosen based on their nutrient content, digestibility, palatability, functionality, availability, and cost. As an example, a typical, nutritionally complete dry dog food with 42 ingredients is examined and the ingredients are discussed here. Safe, healthy pet food starts with safe ingredients sourced from well-monitored suppliers. The ultimate goal of both veterinarians and pet food manufacturers is the same--long healthy lives for dogs and cats.
Article
A 3 × 2 × 2 factorial trial was designed to investigate the effect of different extrusion conditions and product parameters on the nutritional quality as determined by a number of in vitro measurements (e.g. reactive lysine, and starch gelatinization degree) as well as physical quality of the kibble (durability and hardness) of a canine diet. The parameters investigated were mass temperature (110, 130 or 150 °C), moisture content (200 or 300 g/kg) of the diets prior to extrusion and number of times (once or twice) extruded. Total lysine and other amino acids were unaffected by the extrusion conditions employed. Extrusion conditions had a clear effect on the reactive lysine content with the ratio of reactive to total lysine increasing from 0.71 to 0.80 and higher as a result of extrusion and temperature. After a second extrusion, a decrease was observed from a ratio reaching 1.0 to about 0.9. Initial moisture content affected lysine reactivity. Protein digestibility as measured in vitro was not affected by different extruding conditions. There were no obvious differences in protein dispersibility index (PDI) of all the extrudates. In vitro glucose digestibility coefficients as well as starch gelatinization degree (SGD) showed a tendency to increase with an increase in each individual parameter tested. The increase in temperature from 110 to 150 °C as well as extrusion for a second time decreased kibble durability while increasing moisture content increased durability. Optimisation of extrusion conditions during commercial pet food production should include measurement of the reactive to total lysine ratio
Article
The optimal level of beet pulp (BP) inclusion in a meat-based dog diet and the effects of graded levels of dietary BP on fecal excretion responses and mean retention time of marked fiber in the gastrointestinal tract of the dog were evaluated using 30 female English Pointers assigned to isonitrogenous diets containing 0, 2.5, 5.0, 7.5, 10.0 or 12.5% BP (DM basis). Beet pulp replaced portions of dietary cornstarch. Digestibilities of DM and OM decreased by an average of 6% when comparing diets containing BP to the control diet, and quadratic and cubic responses were noted in digestibilities of fiber constituents (lower values at the 7.5 and 10.0% levels, higher values at the 2.5, 5.0 and 12.5% levels). Digestible energy (DE) and ME intakes (kcal/d) were not affected by treatment, but when expressed as a percentage of GE, values decreased (4.8% for DE; 6.2% for ME) linearly with increasing BP levels. Wet weight of feces increased (from 117 to 374 g/d) linearly as percentage of dietary BP increased. Frequency of defecation was higher (P less than .05) for dogs fed the diet containing 12.5% BP than for dogs fed the other diets (5.2 vs mean value of 2.8/24 h). Mean retention time of marked fiber decreased linearly (high value of 23.4 h for the 2.5% BP treatment, low value of 13.0 h for the 10.0% BP treatment) with increased level of BP. Beet pulp levels up to 7.5% of diet DM appear acceptable as a dietary fiber source in a meat-based canine diet.
Article
To evaluate effects of dietary insoluble fiber on control of glycemia in cats with naturally acquired diabetes mellitus. Randomized controlled crossover trial. 16 cats with naturally acquired diabetes mellitus. Cats were fed a diet high in insoluble fiber (HF) containing 12% cellulose (dry-matter basis) or a diet low in insoluble fiber (LF) for 24 weeks; they were fed the other diet for the subsequent 24 weeks. Caloric intake and insulin treatment were adjusted to maintain stable body weight and control of glycemia, respectively. Cats were allowed an adaptation period of 6 weeks after initiation of a diet, after which control of glycemia was evaluated at 6-week intervals for 18 weeks. Variables assessed included serum glucose concentration measured during the preprandial state, blood glycated hemoglobin concentration, serum glucose concentration measured at 2-hour intervals for 12 hours beginning at the time of the morning insulin injection, 12-hour mean serum glucose concentration, and mean fluctuation in serum glucose concentration from the 12-hour mean serum glucose concentration. Mean daily caloric intake, body weight, or daily insulin dosage did not differ significantly between cats when fed HF and LF diets. Mean preprandial serum glucose concentration, most post-prandial serum glucose concentrations, and the 12-hour mean serum glucose concentration were significantly lower when cats consumed the HF diet, compared with values when cats consumed the LF diet. These results support feeding a commercially available diet containing approximately 12% insoluble fiber (dry-matter basis) to cats with naturally acquired diabetes mellitus.
Article
Indigestible compounds are useful for reducing the energy density of food for obese cats, but the acceptance and digestibility of such components must also be taken into consideration. In this trial, dried apple pomace was investigated as a compound having sweet taste, aromatic flavour and high fibre content (207 g/kg dry matter). It was mixed in a meat-based diet at a ratio of 10, 20, and 40%. These diets were fed to adult cats in digestibility trials. As could be predicted, by increasing the percentage of apple pomace in the mixtures the digestibility of nutrients significantly decreased (p < 0.01; p < 0.001). However, the digestibility of ether extract decreased much less than that of the other nutrients. The addition of apple pomace to the diets at an inclusion rate of 10 or 20% reduced their energy density but only slightly changed the digestibility of fat. However, the digestibility of crude protein decreased considerably. According to the present findings, the energy density of mixed diets decreases proportionally to the percentage of apple pomace added. However, due to the much lower digestibility, the protein supply to the cat will be worse. It was concluded that the addition of palatable fibrous components is the best method for reducing the energy content of food for obese cats, as it maintains a normal level of food intake. When calculating the required protein content of a diet supplemented with a fibrous component, in addition to the degree of dilution the reduced protein digestibility must be taken into account.
Article
A study was undertaken to evaluate a high fibre diet used in the management of 10 dogs with naturally occurring insulin-dependent diabetes mellitus. Following baseline measurements of health and glycaemic control, the dogs were fed a canned diet containing a blend of insoluble and soluble dietary fibres and were monitored during the ensuing four months. Switching to the high fibre diet was associated with significantly lower mean 24-hour and postprandial plasma glucose concentrations, which were maintained over the study period. The high fibre diet was also associated with significant reductions in plasma concentrations of fructosamine, glycated haemoglobin, free glycerol and cholesterol, and there were significant improvements in dog activity and demeanour. Bodyweight declined during the fourth month of feeding the diet, which is likely to have resulted from underfeeding relative to increased activity. The results indicate that a high fibre diet can significantly improve glycaemic control and quality of life in dogs with diabetes mellitus.
Article
Functional ingredients are a diverse group of compounds that are intended to produce a positive effect on the health of the consumer. The term "functional" is not meant to differentiate these ingredients from other ingredients historically consumed as part of the food supply that are indeed biologically active constituents, for example, nutrients. Indeed, all foods should be considered "functional". The term functional ingredient is meant to convey the function of these new ingredients, which is to produce a positive health outcome via physiological activity in the body. Functional ingredients encompass elements of drugs, nutrients and food additives. A framework for evaluation of the safety of functional ingredients utilizes an understanding of both the current regulatory frameworks in place as well as the characteristics that define these particular ingredients. The types of studies conducted and the data generated to support safety of functional ingredients is product-specific and can include compositional analysis, structure/toxicity analysis, evaluation of historical and intended exposure, animal studies, clinical/epidemiologic studies, and evaluation of special considerations such as potential for adverse food or drug interactions.
The Effects of Carbohydrate-Free Diets Containing Different Levels of Protein on Reproduction in the Bitch
  • E Kienzle
  • H Meyer
  • I H Burger