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Omnivorous dog traits revisited. Dogs are classified as omnivores based on traits that are different from carnivorous cats. The authors hypothesise that these ‘omnivorous’ traits, highlighted in white boxes, reflect the typical feast-or-famine lifestyle of the carnivorous dog’s ancestor, the wolf. Traits outlined in green and blue are functional for periods of feast and famine, respectively. Dogs share numerous traits with cats, shown in orange. Capacities of traits shown in grey are the target during domestication (Axelsson et al. (2013) The
genomic signature of dog domestication reveals adaptation to a starch-rich diet. Nature 495, 360–364).

Omnivorous dog traits revisited. Dogs are classified as omnivores based on traits that are different from carnivorous cats. The authors hypothesise that these ‘omnivorous’ traits, highlighted in white boxes, reflect the typical feast-or-famine lifestyle of the carnivorous dog’s ancestor, the wolf. Traits outlined in green and blue are functional for periods of feast and famine, respectively. Dogs share numerous traits with cats, shown in orange. Capacities of traits shown in grey are the target during domestication (Axelsson et al. (2013) The genomic signature of dog domestication reveals adaptation to a starch-rich diet. Nature 495, 360–364).

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Domestic dogs diverged from grey wolves between 13 000 and 17 000 years ago when food waste from human settlements provided a new niche. Compared to the carnivorous cat, modern-day dogs differ in several digestive and metabolic traits that appear to be more associated with omnivorous such as man, pigs and rats. This has led to the classification of...

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... Further, the gut microbiome of both species is functionally and structurally similar (17,18). Since their domestication, dogs have been sharing the same food sources as humans (19), and have switched their diet from carnivorous to omnivorous, which gradually modified their digestive and metabolic characteristics, making them closer to those of omnivorous mammals (20). This dietary change further influenced the microbiome of domestic dogs, making it more similar to that of humans. ...
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Although several methods have been developed to improve male fertility and sperm quality, subfertility remains a primary clinical issue in male reproduction worldwide. The aim of this study was to determine the effects of the oral administration of three commensal Lactobacillus spp. on healthy normozoospermic dogs and the qualitative parameters of their sperm. Three weeks of supplementation induced a significant decrease of two phyla, Proteobacteria and Tenericutes, and an increase of phylum Firmicutes. At the species level, the number of Fusobacterium perfoetens and Anaerobiospirillum succiniciproducens decreased, while Limosilactobacillus reuteri increased. Parallel to these results, qualitative sperm parameters such as total and progressive motility, acrosome integrity, and other kinematic parameters were significantly enhanced after commensal lactobacilli supplementation. In addition, we showed that Firmicutes were positively correlated with sperm qualitative parameters, while Proteobacteria, F. perfoetens, and A. succiniciproducens were negatively correlated. Considering the similarities between the gut microbiome of dogs and humans, these results provide more insight into how gut microbiota regulation could improve male sperm quality in both species.
... Dingoes often consume the most abundant species in native ecosystems, including marsupials and reptiles with high protein (P):low fat (F):low carbohydrate (C) content (2). The preferred P:F:C profile of dingoes is currently unknown, but Bosch et al. (57) reported that the selected ratio of wolves is 54:45:1 P:F:C. In contrast, it seems likely that domestic dog evolution is shaped by feeding on starch-rich diets in the Neolithic, high-fat diets during the agricultural revolution and by artificial selection for breed-specific traits. ...
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Dogs are uniquely associated with human dispersal and bring transformational insight into the domestication process. Dingoes represent an intriguing case within canine evolution being geographically isolated for thousands of years. Here, we present a high-quality de novo assembly of a pure dingo (CanFam_DDS). We identified large chromosomal differences relative to the current dog reference (CanFam3.1) and confirmed no expanded pancreatic amylase gene as found in breed dogs. Phylogenetic analyses using variant pairwise matrices show that the dingo is distinct from five breed dogs with 100% bootstrap support when using Greenland wolf as the outgroup. Functionally, we observe differences in methylation patterns between the dingo and German shepherd dog genomes and differences in serum biochemistry and microbiome makeup. Our results suggest that distinct demographic and environmental conditions have shaped the dingo genome. In contrast, artificial human selection has likely shaped the genomes of domestic breed dogs after divergence from the dingo.
... Harbour seals Phoca vitulina consumed only the bellies of pre-spawning female salmon Oncorhynchus nerka containing high-lipidcontent roe (Hauser et al. 2008), while bears Ursus spp. targeted the lipid-rich roe and the brain tissue of salmon (Gende et al. 2001), and wolves will feed initially on the internal organs of large ungulates (Bosch et al. 2015;Kohl et al. 2015). Although we did not directly observe the killer whale pair predating on the white sharks, the rake marks and wounds on the carcasses were distinctly those of killer whales, and the same killer whale pair were observed in the area when predations were known to occur. 2 The same killer whale pair were also implicated in predations on sevengill sharks (Engelbrecht et al. 2019) and bronze whalers in False Bay (SE and colleagues, unpublished data; Supplementary Figure S4), indicating a level of experience and skill in hunting large sharks. ...
... In this light, it may be worthwhile to consider the natural diet of a pig, as this is what the pig's digestive and metabolic system has been adapted to over the course of evolution. A similar approach was taken by others to characterize the 'evolutionary diet' of cats and dogs Bosch et al., 2015). ...
Thesis
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Research with weaned piglets has provided information that dietary fibre (DF) is implicated in gastrointestinal (GIT) maturation and health. Dietary fibre can mitigate the risk for intestinal infections and diarrhoea occurring in pigs that are weaned at 3 to 4 weeks of age, which is common practice on most farms. There is a paucity of scientific information, however, on the role of DF in the diet of suckling pigs. A pig is born with a relatively immature gastrointestinal tract able to digest and absorb nutrients from sow milk. To attain capacity to digest diets containing high levels of vegetable feedstuffs the GIT needs to go through a process of maturation. In a natural setting, a large part of a pig’s diet consists of vegetable fibrous feedstuffs, such as leaves, roots, tubers, fruits, and seeds. Wild boar and feral piglets are anticipated to start consuming non-milk feed items already early in life, including vegetable material. This allows gradual adaptation of the GIT and its harbouring intestinal microbiota to the solid diet before weaning, which is completed in nature at 10-17 weeks of age. The diet of farmed pigs also contains a high proportion of vegetable material, with varying levels of DF. Commercial pre-weaning diets , on the other hand, are formulated to be highly digestible and nutrient-dense, using sow milk as the benchmark. In this regard, there seems to be a major difference in diet characteristics between the natural diet and a typical commercial low-fibre, nutrient dense piglet diet. The implications of this difference for the maturation of the GIT are not known. Chapter 1 provides a literature overview of the significant maturational changes in dentition and the GIT after birth. For this thesis, it was decided to focus on the stomach, small and large intestine, as these organs play a central role in feed digestion and absorption. The available information shows that early nutrition of piglets modulates many aspects of the maturational processes of the GIT and the residential microbiota. The microbiota, mostly bacteria, are starting to colonize the GIT of the piglet from the immediate prenatal period onwards, especially in the large intestine where they are most abundant. Its composition develops with age of the pig in a complex coexistence with the host and the diet. The microbiota thrive on undigested nutrients, sloughed off intestinal cells and secretions (e.g., mucus, enzymes) through a process called fermentation. From the fermentation of carbohydrates, mostly volatile fatty acids are produced, such as acetate, propionate and butyrate. Volatile fatty acids are an energy source for the intestinal mucosa and the host. Furthermore, they play a role in many body processes, such as immune modulation, mineral and water absorption in the hind gut among many others. The end- products from protein fermentation, such as ammonia and branched-chain fatty acids and biogenic amines are mostly regarded as a risk for intestinal health. It is generally accepted that the intestinal microbiota play a pivotal role in GIT maturation and general health of animals, but the underlying mechanisms are still largely unclear. Dietary fibres are characterized by the fact that the pig’s own enzymes are unable to digest them. Consequently, they pass through the stomach and small intestine to subsequently arrive at the level of the large intestine as substrate for the microbiota. For the older pig, the large intestines are well developed, and the microbiome herein capable to digest and ferment DF to a large extent (up to 70%), provided it is well adapted (‘primed’) to the DF. A well-developed microbiome possesses a wide array of enzymes capable of digesting and fermenting DF. Dietary fibres consist of an array of chemical compounds, such as cellulose, hemicellulose, oligosaccharides, lignin, and pectin. Collectively, these compounds determine the physicochemical characteristics of DF and their effect in the GIT. Solubility, in this respect, is relevant as it is associated with the fermentability of the DF by the intestinal microbiota. On the other hand, an insoluble DF may exert maturational effects too, for instance through its bulking and abrasive effects in the GIT. However, a paucity of data exists on how, next to sow milk, DF in supplemental diet affects GIT maturation in suckling piglets. For this thesis we hypothesized that DF is important for early-life GIT maturation. Hence, the aim of this PhD was to evaluate the impact of DF enriched supplemental diets on GIT maturation in suckling pigs, including the capacity and functionality of stomach, small and large intestine, and the priming of GIT microbiota to ferment a typical post-weaning diet with plant-derived carbohydrates. The research questions deduced from this hypothesis were formulated in Chapter 2. A first study was performed to answer the question whether feral piglets start to ingest vegetable material from early life onwards and how this may be associated with GIT maturation (Chapter 3). To this aim, feral piglets were collected, and their age was estimated based on body size and their dentition. Stomachs were weighed and contents were examined to determine particle size distribution and to classify the diet items. Vegetable matter (mainly ‘leaves and stems’) was predominantly present in most piglets, representing a large part of their diet (on average 83% of total stomach contents by weight). This was reported earlier for older wild boars and feral pigs. Approximately 25% of the stomachs of piglets contained curd (clotted sow milk) representing on average 16 % by weight. Other diet items (e.g., insects, fruits, seeds, mammals), were less abundant or absent. The data also indicated that a large proportion of their diets consisted of larger feed particles. The stomach development of the feral pigs appeared to be advanced when compared to stomach of farmed piglets of similar age fed a nutrient-dense, finely ground diet. We inferred from these data that feral suckling piglets consume a variety of non-milk items, mainly consisting of vegetable material with a coarse particle size from their first week of life onwards. Moreover, their diet is associated with an enhanced stomach development compared to those of farmed piglets. In a next experiment (Chapter 4), the effect of DF on GIT maturation in suckling piglets was studied. From day two of life onwards, sow suckled piglets were fed either a nutrient dense, low fibre control diet or diets enriched with two types of DF: a diet with a soluble fermentable DF from wheat; a diet with a largely non-fermentable purified cellulose, or a diet containing both DF sources. Piglets consumed the fibre-containing milk supplements and creep diets well. Upon weaning at 25 days of age, their GIT and large intestinal microbiota composition were evaluated. Stomach size and small intestinal maturation were not affected by diet. Large intestinal fill was increased with the soluble DF only. Large intestinal weight and length was increased in piglets consuming the fibrous diet; length mainly by the insoluble cellulose. Cellulose also decreased ileal pH and tended to increase ileal DM content compared to the control diet. Moreover, the concentration of volatile fatty acids tended to increase in the caecum and especially in the large intestine by supplementation with cellulose. The soluble DF source stimulated caecal propionate only. The microbiota composition showed a high individual variation and only limited dietary impact. Nonetheless, cellulose induced minor shifts in specific genera, with notable reductions of putative pathogens. It was concluded that the DF altered large intestinal morphology with little effect on the small intestine and stomach. Moreover, changes in the large intestine were associated with greater fermentation and changes of the microbiota, with more prominent effects from the low-fermentable cellulose. In Chapter 5, it was investigated whether piglets consuming fibrous supplemental diets prior to weaning were more resilient when exposed to an oral infection with enterotoxigenic E. coli (ETEC) one week after weaning. The suckling piglets were fed the same four supplemental diets as described for chapter 4. Upon weaning at approximately 25 days, piglets were fed the same low-fibre diet. Feed intake and body weight gain did not differ between treatments. Overall, indicators of GIT and general health of the piglets were similar between groups. Therefore, it was concluded that neither the supplementation of the soluble nor the insoluble DF source to the pre-weaning diet improved post-weaning growth or GIT health of piglets. In Chapter 6, the effect of inclusion of fine and coarsely ground oat hulls on gastrointestinal development of suckling pigs was studied. Piglets were fed one of three experimental diets. A finely ground low-fibre, nutrient dense diet served as control diet. For the high-fibre diets, heat-treated starch in the control diet was exchanged with finely or coarsely ground oat hulls. Oat hulls are a source of insoluble, slowly fermentable DF. The suckling piglets were fed the diets for approximately 3.5 weeks with their individual feed intake being recorded two times per day when separated from their dam. Feeding oat hulls did not impede clinical health or production performance of the piglets. The full stomach weights tended to be greater for the coarsely ground oat hulls compared to the finely ground oat hulls, whereas CON was intermediate. The coarse oat hulls increased GIT full weight and the weight of the caecum contents compared to piglets fed the control diet and the diet with finely ground oat hulls. Supplementing oat hulls increased villus height in the small intestines and dry matter concentration of the caecal contents. For the colon, inclusion of oat hulls increased its length, contents weight, short-chain fatty acid concentration and reduced total bacterial count as well as γ-proteobacteria count and proportion. Furthermore, feeding the coarse oat hulls reduced colonic crypt depth when compared to the finely ground oat hulls. It was concluded that supplementing oat hulls to a diet for suckling piglets exerted subtle developmental effects on gastrointestinal morphology and colonic microbial community. These effects were largely independent from the particle size of the oat hulls. In the last experiment (Chapter 7), the growth performance and faecal consistency of piglets from birth to eight weeks of age was recorded with the objective to evaluate the inclusion of oat hulls in the diet during suckling and in the nursery period. From two weeks prior to weaning until two weeks after weaning (phase 1), the same diets were fed as described in chapter 6. For phase 2 of the study (day 14-28 after weaning), the inclusion level of oat hulls was decreased from 15% to 5%. The inclusion of oat hulls resulted in a reduction of the dietary net energy concentration by 12% and 4% for phase 1 and 2, respectively. The general health of all piglets remained good, based on the low morbidity and mortality rates. Pre-weaning feed intake and growth were not affected by diet. Overall, faeces score, body weight gain, feed intake and feed efficiency were similar across treatments. The overall net energy efficiency for weight gain was improved for pigs fed the oat hull diets. It was concluded that diluting pre- and post-weaning diets with oat hulls did not significantly influence performance in piglets. In summary, with DF supplementation of diets for suckling piglets it was possible to alter the maturation of the gastrointestinal tract and large intestinal microbiota. This was associated with greater fermentation activity in the large intestine. The magnitude of the observed changes were, however, subtle. Early feeding of DF may represent a ‘window of opportunity’, but its relevance for post-weaning resilience of the piglet needs to be further elucidated. Still, the work described in this thesis shows that young pigs can adapt to fibrous diets, even before weaning, confirming data in grower-fattener pigs and sows. Further work is warranted to optimize DF nutrition in the youngest category of pigs, both with respect to inclusion level as well as for the period during which fibrous diets are fed. Increasing our understanding of the diet of pigs in nature may advance the development of healthy diets as part of a sustainable pig production system with high welfare standards.
... Hence, control of the total energy intake based on crude fat and carbohydrate contents monitoring in dog food may be beneficial for aging small breed dogs. Dogs are omnivores that eat meat and plants to obtain the essential nutrients [14]. Along with proteins and fats, carbohydrates are a valuable macronutrient for dogs that is needed to provide energy and help the body function. ...
Article
Digestibility of pet food can affect the health of dog, especially of aged animals. To maintain the health of dogs in an overall good status it is necessary to provide nutritionally balanced food. For example, the digestibility of dogs was known to be decreased along aging. In addition, losing teethes is an often event in aged dogs that could induce a problem to eat a large size dry pet food. Nonetheless, few detailed information is available on the most suited feeding for aged dogs. As part of the nutritional study of food for aged dogs, in this study, we tested whether food type impacts on digestibility on adult versus senior dogs. The methodology to measure the digestibility of nutrients was chosen the index method using chromium oxide. Dogs were fed the same commercial dry or wet diets, which were supplemented with 0.5% chromium oxide. The wet food was prepared by adding twice volume of water in the dry food prior to incubated overnight (14–16 hours) at room temperature. After five days, their feces were collected up to a total weight of > 200 g which was the amount to analyze undigested nutrients in feces as 3 repeats. In the apparent total tract digestibility analysis of the experimental breed, no difference in the digestibility of crude protein, crude fat, crude fiber, ash, and energy was observed regarding the moisture content of the food. Noteworthy, the digestibility of nitrogen free extract was significantly increased in senior dogs fed dry dog food compared with adult dogs fed the same diet, whereas no difference was observed between senior and adult dogs fed wet food. The small breed dogs showed similar results to the experimental breed dogs. However, the digestibility of crude fat was additionally affected by age and food type unlike the experimental breed dogs. This finding suggests that the food moisture content affects the digestibility of nutrients in dogs with aging. Hence, it may be helpful to determine the nutrient contents in foods for senior dogs depending on the food type.
... Whether comparable effects of the dietary inclusion of food residues might also occur in cats, however, cannot be directly concluded from the related study in dogs. Dogs are considered to be more omnivorous, whereas cats are strictly carnivorous [6]. The cat's ability to digest starch is lower than that of dogs, whereas the protein requirement is higher [7]. ...
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The potential use of food residues for pet food could significantly contribute to food waste reduction. In the present study, the effects of the inclusion of dried food residues (DFR) (0, 5, 10 and 15%) in a complete diet were evaluated in seven healthy adult cats. At the end of each three-week feeding period, feces were collected. The analysis of the fecal microbiota by 16S rDNA sequencing demonstrated a marked increase of the bacterial alpha-diversity with increasing dietary inclusion levels of DFR. In addition, an increase in the relative abundance of Coriobacteriales, Collinsella and Lachnoclostridum, as well as of propionate and n-valerate in the feces of the cats, was detected. The dietary inclusion of DFR decreased the apparent crude protein digestibility and tended to decrease the apparent crude fat digestibility. Overall, the DFR seemed to be highly fermentable in the intestine of cats, which markedly affected the diversity of the fecal microbiota. As this effect might be critical for a balanced gut microbiota, but also along with the observed depressing effects of DFR on the apparent crude protein and crude fat digestibility, lower inclusion levels are recommended if used as a potential ingredient for cat food in the future.
... 82 kcal and 18% crude protein (Iennarella-Servantez, 2017). Based on an energy density of 5.0 kcal/g (Bosch et al., 2015) and a consumption of 4 kg carcass/day for spotted hyaena (Kerr et al., 2007) and 0.35 kg/day for hooded vulture (Brink et al., 2020), coprophagy of a raw meat diet scat provides ca. 1% ...
Article
Coprophagy is defined as the consumption of one’s own faeces (autocoprophagy) or the faeces of other individuals of the same or other species (allocoprophagy). The consumption of one’s own faeces or the faeces of conspecifics is common, in particular for rodents and lagomorphs. However, the consumption of faeces of individuals of another species has rarely been described for vertebrates. In this study, we describe occurrence of coprophagy of African wild dog faeces by hooded vultures and spotted hyaenas in Mana Pools National Park, Zimbabwe. Between September 2017 and November 2020, we radio-tracked six collared African wild dog packs and recorded interactions with spotted hyaenas and hooded vultures. When spotted hyaenas and/or hooded vultures were present, they engaged in coprophagy of African wild dog faeces in 38.5% and 65.5% of the cases respectively. For both species coprophagy was not related to season, drought, time of day or size of the African wild dog pack. Hooded vultures especially, often engaged in coprophagy when they accompanied African wild dogs while they were resting, suggesting such an association may be intended to have access to faeces. Allocoprophagy in wild vertebrates usually serves as an additional source of energy and/or nutrients. Further research is required to determine the content of African wild dog faeces and the potential nutritional benefits for spotted hyaenas and hooded vultures. However, it is clear from our and other studies that the critically endangered hooded vulture forms close associations with the endangered African wild dog. Such associations may play a role in the hooded vulture's survival and should therefore be considered in the conservation strategy of this species.
... Hewson-Hughes et al. (2013) proposed the macronutrient CP:EE:NFE ratio for the domestic dog diet at approximately 30:63:7, based on intakes of dogs with prior experience of the respective experimental food combinations. Interestingly, in later research (Bosch et al. 2015) nutrient intake has been compared between domestic dogs and wolves. It was found that the wolf diet consists of more protein and is characterized by less total carbohydrate intake (CP:EE:NFE = 54:45:1% by energy). ...
... It was found that the wolf diet consists of more protein and is characterized by less total carbohydrate intake (CP:EE:NFE = 54:45:1% by energy). Furthermore, the authors asserted that the dogs preference for lipid-rich diets is a trait that does not stem from the early domestication of the dog but rather has evolved during the evolution of its forebear, the wolf (Bosch et al. 2015). ...
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In addition to properly balancing nutritional value in accordance with the needs of a dog, estimating the microbiological quality of dog food is crucial in providing healthy and safe foods. The aim of this study was to examine the quality of dry food for adult dogs, with particular reference to: (1) evaluating the nutritional value and compliance with nutritional guidelines for dogs, (2) comparing the nutritional value of dog foods, with particular emphasis on the division into cereal and cereal-free foods, and (3) evaluating their microbiological safety. All thirty-six evaluated dry dog foods met the minimum European Pet Food Industry FEDIAF requirement for total protein and fat content. The total aerobic microbial count in the analyzed dry dog foods ranged from 2.7 × 10² to above 3.0 × 10⁷ cfu/g. In five (14%) dog foods the presence of staphylococci was detected; however, coagulase positive Staphylococcus (CPS) was not found. Mold presence was reported in one cereal-free dog food and in six cereal foods. In none of the analyzed foods Enterobacteriaceae were found, including coliforms, Escherichia coli and Salmonella spp. Bacteria of the genus Listeria and Clostridium as well as yeasts were also not detected. In conclusion, the evaluated dry dog foods had varied microbiological quality. The detected number of microorganisms may have some implications for long-term consumption of contaminated food. The lack of European Commission standards regarding the permissible amounts of microorganisms in pet food may result in insufficient quality control of these products.
... Dogs (Canis familiaris) are possibly the first domesticated species, having diverged from the gray wolf (Canis lupus) more than 15,000 years ago (Freedman et al., 2016). Wolves can be considered true carnivores in their nature with vegetal matter being a minor to negligible component of their overall diet, whereas dogs have adapted to a more flexible anthropogenic diet including starchy food (Bosch et al., 2015). Compared with their wild ancestors, dogs have become more adapted to a starch-rich diet as demonstrated by the pancreatic α-amylase 2B (AMY2B) copy number expansion in the genome of the dog (Axelsson et al., 2013;Arendt et al., 2016;Ollivier et al., 2016;Reiter et al., 2016). ...
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The genomic signature of dog domestication reveals adaptation to a starch-rich diet compared with their ancestor wolves. Diet is a key element to shape gut microbial populations in a direct way as well as through coevolution with the host. We investigated the dynamics in the gut microbiota of dogs when shifting from a starch-rich, processed kibble diet to a nature-like raw meat diet, using wolves as a wild reference. Six healthy wolves from a local zoo and six healthy American Staffordshire Terriers were included. Dogs were fed the same commercial kibble diet for at least 3 months before sampling at day 0 (DC), and then switched to a raw meat diet (the same diet as the wolves) for 28 days. Samples from the dogs were collected at day 1 (DR1), week 1 (DR7), 2 (DR14), 3 (DR21), and 4 (DR28). The data showed that the microbial population of dogs switched from kibble diet to raw diet shifts the gut microbiota closer to that of wolves, yet still showing distinct differences. At phylum level, raw meat consumption increased the relative abundance of Fusobacteria and Bacteroidetes at DR1, DR7, DR14, and DR21 (q < 0.05) compared with DC, whereas no differences in these two phyla were observed between DC and DR28. At genus level, Faecalibacterium, Catenibacterium, Allisonella, and Megamonas were significantly lower in dogs consuming the raw diet from the first week onward and in wolves compared with dogs on the kibble diet. Linear discriminant analysis effect size (LEfSe) showed a higher abundance of Stenotrophomonas, Faecalibacterium, Megamonas, and Lactobacillus in dogs fed kibble diet compared with dogs fed raw diet for 28 days and wolves. In addition, wolves had greater unidentified Lachnospiraceae compared with dogs irrespective of the diets. These results suggested that carbohydrate-fermenting bacteria give way to protein fermenters when the diet is shifted from kibble to raw diet. In conclusion, some microbial phyla, families, and genera in dogs showed only temporary change upon dietary shift, whereas some microbial groups moved toward the microbial profile of wolves. These findings open the discussion on the extent of coevolution of the core microbiota of dogs throughout domestication.
... For instance, their dentition is better suited to slicing (Hamper et al., 2012;Van Valkenburgh, 1991), and their digestive tracts are shorter than those of herbivores (Stevens & Hume, 2004) owing to a decreased requirement for fermentation when digesting animal tissue as opposed to plant tissue. Additionally, taste receptor function is altered in many carnivores, including in felids; there is a loss of sensitivity to sugar in fruits and heightened sensitivity to amino acid and bitter compounds (Bosch et al., 2015;Jiang et al., 2012;Kim et al., 2016;Li & Zhang, 2014). ...
... However, the association between parasite species richness and body weight varies depending on the subject species (Dáttilo et al., 2020); hence, further quantitative study is required to confirm the relationship between host body mass and parasite richness in felids. Several animal species are known to utilize plant physical or chemical aspects against parasites or pathogens (Bosch et al., 2015;de Roode et al., 2013;Hart & Hart, 2018;Huffman, 2003). Consumption of grasses is considered to work as scouring agent against intestinal parasites such as roundworms and tapeworms in canids (Bosch et al., 2015). ...
... Several animal species are known to utilize plant physical or chemical aspects against parasites or pathogens (Bosch et al., 2015;de Roode et al., 2013;Hart & Hart, 2018;Huffman, 2003). Consumption of grasses is considered to work as scouring agent against intestinal parasites such as roundworms and tapeworms in canids (Bosch et al., 2015). Small carnivores might eat plants for parasite control, since the energetic costs of parasite load are relatively high. ...
Article
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Plant‐eating behavior is one of the greatest mysteries in obligate carnivores. Despite unsuitable morphological and physiological traits for plant consumption, the presence of plants in scat or stomach contents has been reported in various carnivorous species. However, researchers’ interpretations of this subject are varied, and knowledge about it is scarce, without any multispecies studies. This study assessed the extent of variation in the frequency of plant occurrence in scat and stomach contents, as well as its relationship with various factors in 24 felid species using data from 213 published articles. Since the frequency of plant occurrence has not always been reported, we created two‐part models and estimated parameters in a Bayesian framework. We found a significant negative relationship between the frequency of plant occurrence and body mass. This may be because plant‐eating behavior reduces the energy loss caused by parasites and increases the efficiency of energy intake, which has a greater importance in smaller animals that have relatively high metabolic rates. This exploratory study highlights the importance of considering plant consumption in dietary studies on carnivorous species to understand the adaptive significance of this behavior and the relationship between obligate carnivores and plants. Plant‐eating behavior is one of the greatest mysteries in obligate carnivores. This study assessed the extent of variation in the frequency of plant occurrence in scat and stomach contents, as well as its relationship with various factors in 24 extant felid species using data from 213 published articles. We found a significant negative relationship between the frequency of plant occurrence and body mass.