Dog Diets Research Articles

An in vitro evaluation of the effects of a Yucca schidigera extract and chestnut tannins on composition and metabolic profiles of canine and feline faecal microbiota

ABSTRACTThe in vitro effect of a Yucca schidigera extract (YSE) and tannins from chestnut wood on composition and metabolic activity of canine and feline faecal microbiota was evaluated. Four treatments were carried out: control diet, chestnut tannins (CT), YSE and CT + YSE. The YSE was added to canine and feline faecal cultures at 0.1 g/l, while CT were added at 0.3 g/l for a 24-h incubation. A total of 130 volatile compounds were detected by means of headspace-solid phase microextraction gas-chromatography/mass spectrometry analyses. Several changes in the metabolite profiles of fermentation fluids were found, including a decrease of alcohols (−19%) and esters (−42%) in feline and canine inoculum, respectively, which was due to the antibacterial properties of tannins. In canine inoculum, after 6 h, YSE + CT caused lower cadaverine concentrations (−37%), while ammonia (−4%) and quinolone (−27%) were reduced by addition of CT. After 24 h, the presence of CT resulted in a decrease of sulphur compounds, such as dimethyl sulphide (−69%) and dimethyl disulphide (−20%). In feline faecal cultures, after 6 h, CT lowered the amount of indole (−48%), whereas YSE tended to decrease trimethylamine levels (−16%). Both in canine and feline inoculum, addition of CT and, to a minor extent, YSE affected volatile fatty acids patterns. In canine faecal cultures, CT exerted a marginal inhibitory effect on Escherichia coli population (−0.45 log 10 numbers of DNA copies/ml), while enterococci were increased (+2.06 log 10 numbers of DNA copies/ml) by YSE. The results from the present study show that YSE and tannins from chestnut wood exert different effects on the composition and metabolism of canine and feline faecal microbiota. In particular, the supplementation of YSE and tannins to diets for dogs and cats may be beneficial due to the reduction of the presence of some potentially toxic volatile metabolites in the animals’ intestine.

BEHAVIORAL VARIANT FTD CAUSED BY UBQLN2 P525S MUTATION, WITHOUT EVIDENCE OF MOTOR NEURON DISEASE

Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD) represent extremes of a spectrum with significant overlap. Numerous gene mutations are known to cause these diseases in isolation or combination. Ubiquilin 2 (UBQLN2) mutations have recently been described and have been shown to cause either pure ALS or combination ALS/FTD. Presentation of a well characterized case of FTD caused by a UBQLN2 mutation without clinical or familial evidence of ALS. A 69-year-old right-handed man with a 2-year history of personality changes, unwelcomed familiarity, and increased gregariousness and embellishments with growing grandeur, at times delusional. There was “lack of filtering” and more childishness, playing with grandchildren “at their level”. Appetitive changes included a diet of Frappuccino's, jelly beans, and devil dogs. Lost $20 000 in a scam. Unable to maintain gainful employment as an information technology consultant. Past medical and psychiatric history: non-contributory. Family history: father passed from liver cancer at 53, mother from dementia at 83, sister with hypochotdriasis, and “bipolar” brother who passed in his 60s from pancreatic cancer. Examination: mild diffuse extrapyramidal syndrome without evidence of pyramidal or lower motor neuron disease. MoCA was 20/30, moderate deficits in attention/concentration with impact on memory, which was fully recovered with cues. Neuropsychological assessment revealed tangentiallity, impulsivity, and impersistence. There were deficits in aspects of learning, attention, and executive functions, with intact contextual memory, language, and visual spatial functions. MRI and FDG-PET scans showed focal frontal and anterior temporal atrophy and hypometabolism. Whole exome sequencing failed to reveal the better known genetic causes of FTD (MAPT, GRN, and C9orf72), but did show a known pathologic P525S mutation of the UBQLN2 gene. In addition, known risk or modifyier genes variants were also absent. Remains without clinical evidence of motor neuron disease 5 years following initial symptoms. To our knowledge, this is the first documented case of an isolated presentation of behavioral variant FTD without ALS, caused by a mutation in UBQLN2. Although still rare, this case further expands the spectrum of diseases caused by this mutation.

Raw Meat-Based Diets in Dogs and Cats.

Feeding pets raw meat-based diets (RMBDs) is commonly practiced by many companion animal owners and has received increasing attention in recent years. It may be beneficial for the animals, but may also pose a health risk for both pets and their owners, as RMBDs may be contaminated by enteric pathogens—such as Campylobacter, Salmonella, and Yersinia—which are the most common zoonotic bacteria causing enteritis in humans. Little information exists on the prevalence of these pathogens in pet food, and thus one aim was to investigate the prevalence of Campylobacter, Salmonella, and Yersinia in commercial RMBDs from retail stores. Little evidence also exists on the significance of raw meat feeding on the shedding of Campylobacter, Salmonella, and enteropathogenic Yersinia in the feces of pets, and therefore, the second goal was to study the presence of these pathogens in dogs and cats fed RMBDs. Polymerase chain reaction (PCR) only sporadically detected Campylobacter, Salmonella, and enteropathogenic Yersinia in RMBDs. These pathogens were not found by culturing, indicating a low contamination level in frozen RMBDs. They were also detected in the feces of dogs and cats, but the association with feeding RMBDs to them remained unclear.

Recovery of insulin sensitivity and optimal body composition after rapid weight loss in obese dogs fed a high-protein medium-carbohydrate diet.

This study investigated the effects of an experimental high-protein medium-carbohydrate diet (protein level, 46% metabolizable energy, ME). First, postprandial plasma glucose and insulin kinetics were determined in steady-state overweight/obese Beagle dogs (28%-41% excess body weight) for an experimental high-protein medium-carbohydrate diet (protein level, 46% ME) and a commercial high-carbohydrate medium-protein diet (protein level, 24%ME) in obese dogs. Secondly, all the dogs were included in a weight loss programme. They were fed the high-protein medium-carbohydrate diet, and the energy allocation was gradually reduced until they reached their optimal body weight. Insulin sensitivity and body composition were evaluated before and after weight loss using a euglycaemic-hyperinsulinaemic clamp and the deuterium oxide dilution technique respectively. For statistical analysis, linear mixed effect models were used with a significance level of 5%. Postprandial plasma glucose and insulin concentrations were substantially lower with the high-protein medium-carbohydrate diet than the high-carbohydrate medium-protein diet. These differences can be explained mainly by the difference in carbohydrate content between the two diets. Energy restriction (35% lower energy intake than in the obese state) resulted in a 2.23±0.05% loss in body weight/week, and the dogs reached their optimal body weight in 12-16weeks. Weight loss was associated with a significant increase in insulin sensitivity. The high-protein medium-carbohydrate dietallowed fat-free mass preservation despite a relatively high rate of weekly weight loss. The increase in insulin sensitivity indicated improved control of carbohydrate metabolism, possible due to weight loss and to the nature of the diet. Thus, a high-protein medium-carbohydrate diet is a good nutritional solution for managing the weight of overweight dogs. This diet may improve glycaemic control, which could be beneficial for preventing or managing impaired glucose tolerance in obese dogs and for safe and successful weight loss while preserving lean body mass.

Evaluation of canine adverse food reactions by patch testing with single proteins, single carbohydrates and commercial foods.

Adverse food reaction (AFR) is an important differential diagnosis for the pruritic dog. It is usually diagnosed by feeding an elimination diet with a novel protein and carbohydrate source for eight weeks followed by subsequent food provocation. A previous study demonstrated that patch testing dogs with foods had a high sensitivity and negative predictability for selection of elimination diet ingredients. The aim of this study was to investigate patch testing with proteins, carbohydrates and dry commercial dog food in dogs to determine whether there was value in patch testing to aid the diagnosis of canine adverse food reaction. Twenty five privately owned dogs, with confirmed AFR, underwent provocation trials with selected food antigens and patch testing. For proteins, carbohydrates and dry dog food the sensitivity of patch testing was 100%, 70% and 22.2%, respectively; the negative predictive values of patch testing were 100%, 79% and 72%. The positive predictive values of patch testing for proteins and carbohydrates were 75% and 74%, respectively. This study confirmed that patch testing may be useful for the selection of a suitable protein source for an elimination diet in dogs with suspected AFR, but not as a diagnostic tool for canine AFR. Results for proteins are more reliable than for carbohydrates and the majority of positive patch test reactions were observed with raw protein. Patch testing with commercial dog food does not seem to be useful.

Effect of dietary mannanoligosaccharide supplementation on nutrient digestibility, hindgut fermentation, immune response and antioxidant indices in dogs

BackgroundUse of prebiotics in companion animal nutrition is often considered advantageous over probiotics because of the ease of handling, ability to withstand processing and storage etc. While most of the studies on prebiotic use in dogs have been done with processed food as basal diet, the response in relation to homemade diet feeding is not very well explored.MethodsThe study was conducted to evaluate the effects of dietary mannanoligosaccharide (MOS) supplementation on nutrient digestibility, hindgut fermentation, immune response and antioxidant indices in dogs. Ten Spitz pups were divided into two groups: control (CON) with no supplementation, and experimental (MOS) wherein the basal diet was supplemented with MOS at 15 g/kg diet. All dogs were fed on a home-prepared diet for a period of 150 days. The study protocol included a digestion trial, periodic blood collection and analysis for lipid profile and erythrocytic antioxidants. Immune response of the animals was assessed towards the end of the feeding period.ResultsResults revealed no significant (P > 0.05) variations in palatability score, intake and apparent digestibility of nutrients between the groups. Faecal score, faeces voided, faecal pH, concentrations of ammonia, lactate and short-chain fatty acids were comparable (P > 0.05) between the two groups. Cell-mediated immune response, assessed as delayed-type of hypersensitivity response, was significantly higher (P < 0.05) in the MOS group. The percent of lymphocyte sub-populations CD4+ and ratio of CD4+:CD8+ were also significantly (P < 0.05) higher in MOS group. The serum IgG levels were similar (P > 0.05) in both the groups. Supplementation of MOS lowered (P < 0.05) serum total- and LDL- cholesterol levels, when compared with the control group. The erythrocytic antioxidant indices were similar (P > 0.05) between the two groups.ConclusionsThe results indicated that supplementation of MOS at the rate of 15 g/kg in the diet of dog augmented the cell-mediated immune response and serum lipid profile without any influences on digestibility of nutrients, hindgut fermentation and antioxidants indices.

A Multi-Isotope Investigation of Human and Dog Mobility and Diet in the Pre-Colonial Antilles

ABSTRACTThe complex relationships between humans and dogs (Canis lupus familiaris) have a very deep and unique history. Dogs have accompanied humans as they colonised much of the world, and were introduced via human agency into the insular Caribbean where they became widespread throughout the Ceramic Age. It is likely that the dynamic interactions between humans, dogs, and their environments in the Caribbean were spatially, chronologically, and socially variable. However, almost no research has specifically addressed the nature, or potential variability, of human/dog interactions in this region. This study presents isotopic (strontium and carbon) evidence bearing on human and dog paleomobility and paleodietary patterns in the pre-colonial Caribbean. The isotope results illustrate a generally high degree of correspondence between human and dog dietary practices at all analysed sites but also slight differences in the relative importance of different dietary inputs. Striking parallels are also observed between the human and dog mobility patterns and shed light on broader networks of social interaction and exchange. Lastly, the paper addresses the possible utility and relevance of canine isotope data as proxies for inferring past human behaviours.

Detection of DNA from undeclared animal species in commercial elimination diets for dogs using PCR.

Elimination diets are the gold standard for the diagnosis of adverse food reactions (AFR). A broad variety of commercial diets are available containing either hydrolysed protein or novel ingredients which claim to be suitable for elimination diets. Contamination may be one factor accounting for the failure of commercial elimination diet trials. To test commercial diets labelled as suitable for elimination diets for dogs, for DNA of animal origin other than that declared on the label. Twelve commercial dry and tinned dog food products were investigated for DNA of animal origin (chicken, turkey, beef, mutton and pork) using PCR testing. In nine of 10 over-the-counter diets, DNA of one or more animal species other than declared on the label was identified. The DNA most frequently detected was derived from beef (n = 8) and pork (n = 6). Two hydrolysed diets only contained DNA of the declared animal source. Over-the-counter "single protein diets" or canned meat products cannot be recommended for the diagnosis of dogs with AFR because contamination may cause the elimination diet to fail.

Trace element measurement for assessment of dog food safety.

The quality of dog diets depends on adequate ingredients capable of providing optimal nutrition and free of contaminants, for promoting long-term health. Trace elements in 95 samples of dry food for dog puppies (n=32) and adults (n=63) of various brands were measured using instrumental neutron activation analysis (INAA). The mass fractions of most elements were within the permissible limits for dogs. Aluminum, antimony, and uranium presented fairly high levels in some samples, which may imply health risks. Aluminum mass fractions ranged from <21 to 11,900mg/kg, in same brand, super-premium dog food. Antimony mass fractions ranged up to 5.14mg/kg, with the highest values measured in six samples of dog food from the same producer. The mass fractions of uranium was found up to 4mg/kg in commercial brands from five different producers.

Nutritional evaluation of home-prepared diets for adult dogs at maintenance

Nutritional evaluation of home-prepared diets for adult dogs at maintenance

Effect of enzyme supplements on macronutrient digestibility by healthy adult dogs.

Some enzyme supplement products claim benefits for healthy dogs to compensate for alleged suboptimal production of endogenous enzymes and the loss of enzymes in commercial pet foods secondary to processing. The objective of the current study was to determine macronutrient and energy digestibility by healthy adult dogs fed a commercial maintenance diet with or without supplementation with plant- and animal-origin enzyme products at the dosage recommended by their respective manufacturers. A group of fourteen healthy neutered adult Beagle dogs (average age 8 years) was divided into two equal groups and fed the basal diet alone and then with either the plant- or animal-origin enzyme supplement in three consecutive 10-d periods; the treatment groups received the opposite enzyme supplement in the third period. Digestibility in each period was performed by the total faecal collection method. Serum trypsin-like immunoreactivity (TLI) was measured at the end of each trial. Data were analysed by repeated measures and the α level of significance was set at 0·05. There were no differences in energy and nutrient digestibility between enzyme treatments. When comparing basal with enzyme supplementation, fat digestibility was higher for the basal diet compared with the animal-origin enzyme treatment, which could be a period effect and was not biologically significant (94·7 v. 93·5%). Serum TLI was not affected by supplementation with either enzyme product. Exogenous enzyme supplementation did not significantly increase digestibility of a typical commercial dry diet in healthy adult dogs and routine use of such products is not recommended.

Efficacy and Tolerance of Two Low-Carbohydrate Diets in Large Adult Dogs with Digestive Sensitivity: A Randomized, Cross-Over, Blinded Evaluation

Objective: The objective of this study was to assess the efficacy and gastrointestinal tolerance of a new dry low carbohydrate diet, Sensitive Digest Adult Dog (SENSI) formulated for adult dogs with sensitive digestive systems in comparison with the Adult Dog Large and Medium (ADULT) diet from the same VeterinarytM HPM range. Methods: Dogs with digestive sensitivity were included in a two-period, twosequence crossover study. They were randomly divided into two groups being fed, after a 4-day diet transition, exclusively and successively with each of the two tested diets over a 28-day period. Digestive parameters were evaluated by owners, through online multiple-choice questionnaires, on D0, D7, D28 and D56. Sign and Mc Nemar’s tests were used to perform intra- and inter-group comparisons (α=0.05). Results: One hundred and twenty-one client-owned adult dogs completed the study. Both diets improved daily defecation frequency, faecal score, odour and volume, and flatulence frequency in comparison with the normal diet of the dog. Significant differences (p<0.01) were observed as soon as 7 days after the change of diet. SENSI continued to upgrade digestive parameters after a 28-day feeding period with ADULT, with significant differences for faecal volume (p<0.05). When ADULT was administered after SENSI, the digestive parameters, except defecation frequency, were degraded, and this was significant for faecal consistency (p<0.001). No side effect was reported by the owners. Both diets were rated as highly palatable by owners, and preferred to the usual diets by about 50% of the dogs. Over 79% of owners were satisfied by the test diets, the satisfaction rate and mean score being however significantly higher with SENSI. Conclusion: ADULT and SENSI were both well tolerated and improved digestive parameters in dogs with digestive sensitivity. On few parameters, the improvement was significantly higher with SENSI compared to ADULT. It was concluded that SENSI represents a valuable alternative to ADULT in dogs with sensitive digestive systems.

Analysis of recipes of home-prepared diets for dogs and cats published in Portuguese.

The present study evaluated recipes of home-prepared diets for dogs and cats published in Portuguese. A total of 106 diets were evaluated: eighty for dogs, twenty-four for cats and two intended for both species. A commercial software package was used to analyse the diets, and an ingredient chemical composition database was built based on the Brazilian Tables of Food Composition and United States Department of Agriculture Nutrient Database. The estimated chemical composition of each recipe was compared with the Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs (Fédération Européenne de L'industrie des Aliments Pour Animaux Familiers; FEDIAF, 2014) recommendations for maintenance (as units/MJ). Most recipes (48%) had no precise determination of ingredients and quantities. All diets had at least one nutrient below the recommendations, and all investigated nutrients were deficient in at least one diet. The most frequent nutrients below recommendation were: Fe (68·3% of the recipes for dogs; 100% of the recipes for cats); vitamin E (82·9% of the dog recipes; 84·6% of the cat recipes); Zn (75·6% for dogs; 88·4% for cats); Ca (73·2% for dogs; 73% for cats); Cu (85·4% for dogs; 69·2% for cats); choline (85·4% for dogs; 69·2% for cats); riboflavin (65·8% for dogs; 11·5% for cats); thiamine (39% for dogs; 80·7% for cats); and vitamin B12 (61% for dogs; 34·6% for cats). These recipes may potentially expose animals to nutritional deficiencies, and it is important to inform the owners of the risks of providing home-prepared diets. Better training of professionals that intend to prescribe home-prepared diets is advisable.

Comparison of voluntary food intake and palatability of commercial weight loss diets in healthy dogs and cats.

BackgroundObesity in dogs and cats is usually managed by dietary energy restriction using a purpose-formulated weight loss diet, but signs of hunger and begging commonly occur causing poor owner compliance. Altering diet characteristics so as to reduce voluntary food intake (VFI) can improve the likelihood of success, although this should not be at the expense of palatability. The aim of the current study was to compare the VFI and palatibility of novel commercially available canine and feline weight loss diets.MethodsThe relative performance of two canine (C1 and C2) and two feline (F1 and F2) diets was assessed in groups of healthy adult dogs and cats, respectively. Diets varied in energy, protein, fibre, and fat content. To assess canine VFI, 12 (study 1) and 10 (study 2) dogs were offered food in 4 meals, for 15 min on each occasion, with hourly intervals between the meals. For feline VFI, 12 cats were offered food ad libitum for a period of 18 h per day over 5 consecutive days. The palatability studies used separate panels of 37 dogs and 30 cats, with the two diets being served, side-by-side, in identical bowls.ResultsIn dogs, VFI was significantly less for diet C1 than diet C2 when assessed on energy intake (study 1, 42% less, P = 0.032; study 2, 28% less, P = 0.019), but there was no difference in gram weight intake (study 1: P = 0.964; study 2: P = 0.255). In cats, VFI was 17% less for diet F1 than diet F2 when assessed by energy intake (P < 0.001), but there was again no difference in gram weight (P = 0.207). There was no difference in palatability between the two canine diets (P = 0.490), whilst the panel of cats diet preferred F1 to F2 (P < 0.001).ConclusionFoods with different characteristics can decrease VFI without affecting palatability in both dogs and cats. The effects seen could be due to decreased energy content, decreased fat content, increased fibre content, different fibre source, and increased protein content. Further studies are now needed to determine whether similar findings occur in obese dogs and cats on controlled weight loss programmes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-016-0899-x) contains supplementary material, which is available to authorized users.

0422 The amino acid composition and protein quality of various poultry and vegetable proteins commonly used in the production of dog and cat diets

0422 The amino acid composition and protein quality of various poultry and vegetable proteins commonly used in the production of dog and cat diets

Apparent total tract macronutrient digestibility, fecal characteristics, and fecal fermentative end-product concentrations of healthy adult dogs fed bioprocessed soy protein1

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

A new in vitro method to evaluate digestibility of commercial diets for dogs

The aim of the present study was to develop a new in vitro method for evaluating the digestibility of commercial diets for dogs. First, in order to develop the in vitro method, the digestibility of four commercial diets for dogs was evaluated through several in vitro trials and results were compared with those that were retrieved from the literature. The in vitro method that was developed consists of two incubation phases, a first lasting 2h and taking place in the presence of pepsin, gastric lipase and HCl (gastric phase) and a second 4h one with pancreatin and bile salts (intestinal phase). Later, digestibility of 16 extruded diets for dogs was evaluated both in vivo with adult dogs and in vitro. There was a close linear relationship between in vivo total tract and in vitro dry matter digestibility (r2 = .81), whereas accuracy of crude protein digestibility using the in vitro method was lower (r2 = .51). Linear regression accuracy for ether extract and starch digestibility was low, but the digestibility results obtained with the in vitro method (95.3 and 98.7% for ether extract and starch, respectively) were very close to those from the in vivo trial (average digestibility of ether extract and starch was 94.8 and 99.1%, respectively). The present in vitro method has proved to be a relatively simple, quick procedure for predicting the digestibility of commercial diets for dogs. The utilisation of such a method may significantly reduce the need for in vivo digestion trials with dogs.

Use of distillers dried grains with solubles (DDGS), with and without xylanase, in dog food

The effects of different levels of inclusion of distillers dried grains with solubles (DDGS) with and without the addition of xylanase in extruded diets for dogs on total tract apparent macronutrient digestibility, faecal characteristics and palatability were evaluated in two experiments. In the first experiment, the coefficients of total tract apparent digestibility (CTTAD) and faecal characteristics were measured in eight adult Beagle dogs according to a 8×8 Latin square design. The following diets were evaluated: 0, 60, 120 and 180g/kg of DDGS (as fed) with and without added xylanase. In the second experiment, the palatability of the diets was evaluated in separate tests to make three pair-wise comparisons: 0 vs 60g/kg of DDGS, 0 vs 180g/kg of DDGS and 180g/kg of DDGS without enzyme vs 180g/kg of DDGS with enzyme. Increasing the level of DDGS linearly reduced the CTTAD ether extract after acid hydrolysis (EEAH), gross energy (GE) and estimated metabolizable energy (ME). However, the CTTAD dry matter (DM), crude protein (CP) and organic matter (OM) indicated an increase in diet digestibility after xylanase supplementation (P<0.05). The DDGS CTTAD CP, EE, and DM, which were estimated from regression analyses, were 0.76, 0.63, and 0.59, respectively. Regarding faecal characteristics, no differences were observed for ammonia and faecal score. However, pH decreased as the dietary inclusion of DDGS increased (P<0.05). The dietary inclusion of 180g/kg (as fed) of DDGS improves palatability. Results indicated that the addition of DDGS reduces diet digestibility, however this effect can be attenuated by dietary xylanase supplementation.

Diet adaptation in dog reflects spread of prehistoric agriculture.

Adaptations allowing dogs to thrive on a diet rich in starch, including a significant AMY2B copy number gain, constituted a crucial step in the evolution of the dog from the wolf. It is however not clear whether this change was associated with the initial domestication, or represents a secondary shift related to the subsequent development of agriculture. Previous efforts to study this process were based on geographically limited data sets and low-resolution methods, and it is therefore not known to what extent the diet adaptations are universal among dogs and whether there are regional differences associated with alternative human subsistence strategies. Here we use droplet PCR to investigate worldwide AMY2B copy number diversity among indigenous as well as breed dogs and wolves to elucidate how a change in dog diet was associated with the domestication process and subsequent shifts in human subsistence. We find that AMY2B copy numbers are bimodally distributed with high copy numbers (median 2nAMY2B=11) in a majority of dogs but no, or few, duplications (median 2nAMY2B=3) in a small group of dogs originating mostly in Australia and the Arctic. We show that this pattern correlates geographically to the spread of prehistoric agriculture and conclude that the diet change may not have been associated with initial domestication but rather the subsequent development and spread of agriculture to most, but not all regions of the globe.

Tracking the origins and diet of an endemic island canid (Urocyon littoralis) across 7300 years of human cultural and environmental change

Abstract Understanding how human activities have influenced the foraging ecology of wildlife is important as our planet faces ongoing and impending habitat and climatic change. We review the canine surrogacy approach (CSA)—a tool for comparing human, dog, and other canid diets in the past—and apply CSA to investigate possible ancient human resource provisioning in an endangered canid, the California Channel Islands fox (Urocyon littoralis). We conducted stable isotope analysis of bone collagen samples from ancient and modern island foxes (n = 214) and mainland gray foxes (Urocyon cinereoargenteus, n = 24). We compare these data to isotope values of ancient humans and dogs, and synthesize 29 Accelerator Mass Spectrometry (AMS) radiocarbon dates that fine-tune the chronology of island foxes. AMS dates confirm that island foxes likely arrived during the early Holocene (>7300 cal BP) on the northern islands in the archipelago and during the middle Holocene (>5500 cal BP) on the southern islands. We found no evidence that island foxes were consistently using anthropogenic resources (e.g., food obtained by scavenging around human habitation sites or direct provisioning by Native Americans), except for a few individuals on San Nicolas Island and possibly on San Clemente and Santa Rosa islands. Decreases in U. littoralis carbon and nitrogen isotope values between prehistoric times and the 19th century on San Nicolas Island suggest that changes in human land use from Native American hunter-gatherer occupations to historical ranching had a strong influence on fox diet. Island foxes exhibit considerable dietary variation through time and between islands and have adapted to a wide variety of climatic and cultural changes over the last 7300 years. This generalist foraging strategy suggests that endemic island foxes may be resilient to future changes in resource availability.