True Carnivores Research Articles

Nutritional risks and consequences of meat-only diets for dogs and cats

Suitable nutrition is one of the most significant issues that always needs to be considered in the health mainte-nance of living beings. One of the misconcep-tions of many societies is the exclusive feeding of meat to cats and dogs. Dogs and cats are carnivorous animals; more specifically, cats are strict or true carni-vores, while dogs are omnivores. Although cats are true carni-vores, an exclusive diet of meat will not cover their needs. Wholly meat-based diets might be rich in many nutri-ents and minerals, but they are poor in digesti-ble carbohydrates and fiber. Lack of carbohy-drates can cause gas-trointestinal problems and diarrhea. Also, due to hypovitaminosis A and D caused by such diets, skeletal diseases can be one of the seri-ous consequences. High dietary phosphate > 11.8 g in dry matter (DM) reduces renal phosphate reabsorption and increases vulnera-bility to chronic kidney disease. As phosphate excretion and reduction of calcium reabsorption continue, bone decom-position, symptoms of osteoporosis, and sec-ondary hyperparathy-roidism occur. In wholly meat-based canine di-ets, a lack of carbohy-drates compels the an-imal to use protein in the gluconeogenesis process to produce glu-cose. As a result, the body goes through pro-tein deficiency and its side effects. To main-tain digestive system health and prevent diar-rhea, the diet must in-clude soluble fiber. Al-so, the presence of car-bohydrates and fats is essential. Preserving the correct calcium-to-phosphorus ratio (Ca:P) can be solved by adding carbohydrates or using meats with a lower phosphorus content.

Bacterial Metabolism of Polyphenol‐rich Fibers in a True Carnivore, Felis catus

Domestic cats, Felis catus, are true carnivores with short gastrointestinal (GI) tracts, rapid GI transit, minimal production of enzymes for carbohydrate digestion & vestigial ceca. These characteristics suggest cats have limited ability to effectively metabolize fiber; however, rich sources of plant‐derived polyphenols & fermentable carbohydrates may benefit feline GI health. 30 adult cats (healthy or with mild GI distress) consumed the Control food (CF) during a 3 week prefeed. Cats were randomized to either CF or Test food (TF) for a 4 week treatment period then crossed to the opposite food for 4 weeks (CF: 3913 kcal/kg, 1.5 g total dietary fiber, TDF; 0.2 g soluble fiber, SF; & 1.3 g insoluble fiber, INSF, per 100 kcal; TF: 3991 kcal/kg, 2.2 g TDF, 0.4 g SF, 1.8 g INSF per 100 kcal). All foods were complete & balanced, fed in dry form & met 2017 AAFCO maintenance guidelines. Fiber sources included, CF: corn & cellulose; TF: corn, ground pecan shells, flaxseed, dried citrus pulp, dried beet pulp, & cranberry pomace. Feces were collected on prefeed day 18 & on treatment days 24 & 52, scored on a 5 point scale (1= >75% liquid to 5= >90% firm), cleaned, homogenized, & frozen at −70C. Microbiome 16s sequencing was performed; count‐normalized data were CLR transformed. Untargeted metabolomics analysis was performed by a commercial lab. Fecal short chain fatty acids were analyzed using liquid‐liquid extraction & gas chromatography with flame ionization detection. Results were compared at 4 weeks using paired t‐tests with a significance threshold of p<0.05. Cats had free access to water & were housed with natural daylight & enrichment provided by toys, other cats & people. This study was reviewed & approved by the Institutional Animal Care & Use Committee, Hill's Pet Nutrition, Inc. TF significantly increased fecal propionic acid & decreased pH vs. CF while maintaining acceptable stool scores; there was a trend toward increased acetate. TF increased acetate & propionate‐producing bacterial taxa including Bacteroides, Clostridia, Prevotella, & Ruminococci. TF increased fecal saccharolytic products including erythrose, fucose, maltose, ribulose/xylulose, glucose, arabinose, glucuronate, fructose, xylose, & mannose. Fecal anti‐inflammatory & antioxidant plant compounds including eriodictyol, hesperidin, naringenin, limonin, & ponciretin from citrus, secoisolariciresinol diglucoside from flax, & ferulate, quinate, sinapate, vanillate & gentisate organic acids were increased in TF‐fed cats. TF also increased fecal hesperetin, secoisolariciresinol & dihydroferulic acid. TF with fibers rich in polyphenols and fermentable carbohydrates increased fecal saccharolytic & fermentative metabolites, lowered fecal pH and increased fermentative bacterial taxa, indicating increased fiber metabolism. TF increased anti‐inflammatory & antioxidant plant polyphenols in the lower GI tract of cats and promoted bacterial transformation of polyphenols to biologically active postbiotics. The specialized polyphenol‐rich fiber sources found in TF may be beneficial in optimizing feline GI health.Support or Funding InformationThis study was funded by Hill's Pet Nutrition, Inc.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Dietary nutrient profiles of wild wolves: insights for optimal dog nutrition?

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 dogs as omnivores, but the origin of these 'omnivorous' traits has, hitherto, been left unexplained. We discuss the foraging ecology of wild wolves and calculate the nutrient profiles of fifty diets reported in the literature. Data on the feeding ecology of wolves indicate that wolves are true carnivores consuming a negligible amount of vegetal matter. Wolves can experience prolonged times of famine during low prey availability while, after a successful hunt, the intake of foods and nutrients can be excessive. As a result of a 'feast and famine' lifestyle, wolves need to cope with a highly variable nutrient intake requiring an adaptable metabolism, which is still functional in our modern-day dogs. The nutritive characteristics of commercial foods differ in several aspects from the dog's closest free-living ancestor in terms of dietary nutrient profile and this may pose physiological and metabolic challenges. The present study provides new insights into dog nutrition and contributes to the ongoing optimisation of foods for pet dogs.

Phylogenetics and character evolution in the carnivorous plant genus Genlisea A. St.-Hil. (Lentibulariaceae)

The carnivorous plant genus Genlisea A. St.-Hil. (Lentibulariaceae) comprises at least 22 species distributed in South and Central America as well as in Africa (including Madagascar). It has only recently been shown to be a true carnivore, specialized in protozoa and other small soil organisms. Here we present a statistically highly supported phylogeny of Genlisea based on three chloroplast loci. The most recent common ancestor of Genlisea most likely was of Neotropical origin and characterized by pedicels that are recurved in fruit, a strongly glandular inflorescence, and bivalvate capsule dehiscence. The further evolution of various morphological characters during the diversification of the genus is discussed. The two previously suggested subgenera Tayloria and Genlisea correspond to the two major clades found in our analyses. In subgenus Genlisea, three clades can be clearly distinguished based on molecular and morphological characters and on biogeographic patterns, which led us to propose a new sectional classification.

The glucose and insulin response to isoenergetic reduction of dietary energy sources in a true carnivore: the domestic cat (Felis catus)

The present study assessed the effect of separate reduction of each energy-delivering nutrient - protein, fat and carbohydrate - on glucose tolerance and insulin response in a strict carnivore: the domestic cat (Felis catus). Three isoenergetic, home-made diets with the following energetic distribution, low protein (LP): protein 28 % of metabolisable energy; fat 43 %; nitrogen-free extract 29 %; low fat: 47, 27 and 25 %; low carbohydrate (LC): 45, 48 and 7 %, were tested in a 3 x 3 Latin square design. Nine healthy normal-weight cats were randomly assigned to each of the diets in a random order at intervals of 3 weeks. At the end of each testing period, intravenous glucose tolerance tests were performed. Plasma glucose concentrations and area under the glucose curve showed no differences. Area under the insulin curve was lower when cats were fed the LP diet, and the second insulin peak tended to be delayed when the LC diet was fed. In contrast to other studies, in which energy sources were elevated instead of being reduced, the present trial contradicts the often suggested negative impact of carbohydrates on insulin sensitivity in carnivores, and shows that reducing the dietary carbohydrate content below common amounts for commercial foods evokes an insulin-resistant state, which can be explained by the cats' strict carnivorous nature. It even points to a negative effect of protein on insulin sensitivity, a finding that corresponds with the highly gluconeogenic nature of amino acids in strict carnivores.

Hindgut fermentation in dogs

There is a large body of research investigating the nutritional needs of the dog at different life-stages and the use of different feed ingredients in commercial diets (Clapper et al, 2001; Schroeder & Smith, 2008). Despite this, though there has been relatively little published work looking at the role the large intestine plays in nutrient digestion in the dog. The dog’s gastro-intestinal tract has been compared to the cat’s in terms of relative length. However the cat is a true carnivore and has little need to ferment fibre from the diet, whereas the dog is a scavenger and will consume a much wider range of food, and therefore may need to ferment fibrous material from the diet. The dog may therefore require a more developed large intestine to harbour a microbial population to aid in the digestion of this fibrous material. This study was performed to determine differences in digestion of nutrients in this segment of the canine gastrointestinal tract.

Transfer of lipids from plankton to blubber of harp and hooded seals off East Greenland

Sub-Arctic marine ecosystems are some of the most productive ecosystems in the world's oceans. The capacity of herbivorous zooplankton, such as Calanus, to biosynthesize and store large amounts of lipids during the short and intense spring bloom is a fundamental adaptation which facilitates the large production in these ecosystems. These energy-rich lipids are rapidly transferred through the food chain to Arctic seals. The fatty acids and stable isotopes from harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) off East Greenland as well as their potential prey, were analysed. The results were used to describe the lipid dynamics and energy transfer in parts of the East Greenland ecosystem. Even if the two seal species showed considerable overlap in diet and occurred at relatively similar trophic levels, the fatty acid profiles indicated that the bases of the food chains of harp and hooded seals were different. The fatty acids of harp seals originate from diatom-based food chain, whereas the fatty acids of hooded seals originate from dinoflagellate and the prymnesiophyte Phaeocystis pouchetii-based food chain. Stable isotope analyses showed that both species are true carnivores on the top of their food chains, with hooded seal being slightly higher on the food chain than harp seal.

Shift between carnivory and omnivory in stream stonefly predators

AbstractOmnivory can have profound effects on the trophic dynamics of communities and ecosystems, as they may interact with multiple trophic levels simultaneously. Some species of large‐bodied stoneflies may be viewed as omnivores rather than true carnivores even at later nymphal stages. We evaluated the seasonal change in the diet of stonefly predators by analyzing their stable isotope ratio, gut contents, physiological activity, and food availability. A two‐source‐based mixing model based on stable isotope analysis revealed that stoneflies shifted their diet between carnivory in summer and omnivory in winter—despite the higher availability of animal prey in winter. The gut content analysis showed that swift prey (mayflies) were consumed in the summer, whereas sluggish prey (Chironomidae) were consumed in the winter. The physiological activity of stoneflies also declined markedly in winter. These results suggest that, in winter, stoneflies foraged on a mixture of Chironomidae and algae. It appears that omnivory in some stream consumers is related to the seasonal change in temperature‐dependent physiological activity, rather than prey availability.

Meat in the human diet: An anthropological perspective

Human ancestral diets changed substantially approximately four to five million years ago with major climatic changes creating open grassland environments. We developed a larger brain balanced by a smaller, simpler gastrointestinal tract requiring higher-quality foods based around meat protein and fat. Anthropological evidence from cranio-dental features and fossil stable isotope analysis indicates a growing reliance on meat consumption during human evolution. Study of hunter-gatherer societies in recent times shows an extreme reliance on hunted and fished animal foods for survival. Optimal foraging theory shows that wild plant foods in general give an inadequate energy return for survival, whereas the top-ranking food items for energy return are large hunted animals. Numerous evolutionary adaptations in humans indicate high reliance on meat consumption, including poor taurine production, lack of ability to chain elongate plant fatty acids and the co-evolution of parasites related to dietary meat.

Fluorescence Labelling of Phosphatase Activity in Digestive Glands of Carnivorous Plants

A new ELF (enzyme labelled fluorescence) assay was applied to detect phosphatase activity in glandular structures of 47 carnivorous plant species, especially Lentibulariaceae, in order to understand their digestive activities. We address the following questions: (1) Are phosphatases produced by the plants and/or by inhabitants of the traps? (2) Which type of hairs/glands is involved in the production of phosphatases? (3) Is this phosphatase production a common feature among carnivorous plants or is it restricted to evolutionarily advanced species? Our results showed activity of the phosphatases in glandular structures of the majority of the plants tested, both from the greenhouse and from sterile culture. In addition, extracellular phosphatases can also be produced by trap inhabitants. In Utricularia, activity of phosphatase was detected in internal glands of 27 species from both primitive and advanced sections and different ecological groups. Further positive reactions were found in Genlisea, Pinguicula, Aldrovanda, Dionaea, Drosera, Drosophyllum, Nepenthes, and Cephalotus. In Utricularia and Genlisea, enzymatic secretion was independent of stimulation by prey. Byblis and Roridula are usually considered as "proto-carnivores", lacking digestive enzymes. However, we found high activity of phosphatases in both species. Thus, they should be classified as true carnivores. We suggest that the inflorescence of Byblis and some Pinguicula species might also be an additional "carnivorous organ", which can trap a prey, digest it, and finally absorb available nutrients.

Carnivory in pitcher plants of the genus Heliamphora (Sarraceniaceae)

summaryField studies of Heliamphora nutans Benth., H. heterodoxa Steyerm., H. minor Gleason, H. ionasii maguire and H. tatei Gleason in the Guayana Highlands of Venezuela, show that the last named species is a true carnivore, possessing all of the following traits: attraction of prey through special visual and chemical signals, trapping and killing of prey, digestion of prey through secreted enzymes, presence of commensals, presence of wax scales aiding in the capture of prey, and absorption of nutrients. The other species possess all traits except they seem neither to secrete proteolytic enzymes nor produce wax scales. The pattern of the carnivorous syndrome among Heliamphora species suggests that the carnivorous habit has evolved in nutrient–poor habitats to improve the absorption of nutrients by capturing mainly ants and only H. tatei further evolved mechanisms for rapid assimilation of organic nutrients and for capturing a variety of flying insects. The carnivorous traits are lost in low light conditions, indicating that nutrient supply is limiting only under fast growth.

Comparative paleoecology of Paleogene and Neogene mammalian faunas: guild structure and diversity

We examined guild structure and diversity in the mammalian biota of the Paleogene of Wyoming and Montana and the Neogene of Pakistan. Trophic structure was measured as frequency of generic diversity in each of the following trophic categories: insectivore, omnivore, frugivore, herbivore, and carnivore. Trophic categories were inferred from dental morphology.Results are summarized below (see graphs). In Wyoming/Montana, the Paleocene is dominated by herbivores (from the orders Condylarthra, Multituberculata, and Pantodonta) and insectivores (“Proteutheria” and Proprimates). In the early Eocene, herbivores (Perissodactyla, Artiodactyla, and Rodentia), carnivores (Carnivora, Creodonta, and Mesonychia), and insectivores (“Proteutheria,” Proprimates, and Primates) dominate. At the beginning of the Eocene, carnivores and insectivores are more diverse than herbivores, but later, herbivores are more diverse. Adapid primates become an important frugivore element in the early Eocene. Herbivores are the most common group throughout the sequence, ranging from 30% to 75% of all specimens.In the Siwaliks, herbivores (from Proboscidea, Rodentia, Perissodactyla, and Artiodactyla) dominate in generic diversity (70–80%), with artiodactyls consistently representing about 50% of herbivore genera. Circa 16 Ma, rodents appear and become an important herbivore group. At 14 Ma, bovid diversity increases dramatically. Specialized browsers (tragulids, giraffids) and grazers (suids) represent 25% to 35% of herbivore diversity throughout the sequence. Carnivores, represented by creodonts and true carnivores, range from 5% to 20% of generic diversity in the Siwaliks. At 11 Ma, carnivores increase in generic diversity with amphicyonid and hyaenid carnivores dominating the guild. Carnivores and insectivores are never as diverse in the Siwaliks as they are in the early Eocene of North America.

Metabolic basis for some of the nutritional peculiarities of the cat

ABSTRACTThe nutritional requirements of most mammals exhibit a remarkable degree of similarity, a reflection of common evolutionary origin. However, among mammals two groups, ruminants and carnivores, appear to possess the greatest divergence in dietary requirements. The former group have been extensively studied, their nutritional peculiarities arising from a specialized pregastric digestive system. Carnivores have been largely neglected by nutritionists, and yet offer a most interesting divergence in dietary requirements amongst mammals. It would appear that the specialized diet, i.e. animal tissue, of true carnivores has permitted metabolic adaptation through modification of enzymes and enzyme systems which are expressed as peculiarities in nutritional requirements. The purpose of this paper is to review the metabolic basis for some of the nutritional peculiarities of the domestic cat, a true carnivore which has received the most attention.The following nutrients, or metabolic functions, are discussed: vitamin A, niacin, taurine, arginine, gluconeogenesis, nitrogen conservation and essential fatty acids. The latter two topics are covered by other discussants at this symposium and are only included here for completeness. The reader is requested to consult the relevant papers of Rogers & Morris (1982) and Rivers (1982).

Food, feeding rates and assimilation in woodland snails.

Analyses of the faeces of seven species of woodland, litterdwelling snails (Marpessa laminata, Clausilia bidentata, Oxychilus cellarius, O. alliarius, Discus rotundatus, Arianta arbustorum and Hygromia striolata), showed that all feed predominently on higher plant material, be it living or dead. H. striolata and A. arbustorum took more chlorophyll-containing plant material than the other species, D. rotundatus had a significant amount of fungus in its faeces, while the faeces of O. cellarius and O. alliarius contained significant amounts of animal material.The consumption and assimilation of a variety of foods by molluscs was studied in the laboratory using an ash-ratio technique, which had been shown to give similar results to those obtained by the standard gravimetric technique. The assimilation efficiency of the molluscs was found to be temperature independent, but ingestion rates and absolute assimilation rates were temperature dependent. The assimilation efficiency of D. rotundatus on living plant material (three field layer species) was 44.8±4.43% that of H. striolata (Urtica dioica) was 52.4±8.78% while O. cellarius and H. aspersa (on Lactuca sativa) had assimilation efficiencies of 70.2±4.40% and 53.50±6.04% respectively. The results fall within the range shown by other invertebrate groups. The assimilation efficiency of D. rotundatus on leaf litter (a mean of 49.1±1.88% on five litter types) was higher than that shown by other invertebrates, probably due to the presence of gut polysaccharidases. The assimilation on dead earthworm as animal material (86.9±2.53% with O. alliarius and 78.6±6.73% with D. rotundatus) was in the range of true carnivores. Consumption rates were more variable; Urtica dioica, amongst living material, was eaten in greatest quantity; Acer pseudoplatanus, Castanea sativa and Quercus robur litter were eaten in greater quantity than Fagus sylvatica and Carpinus betulus. Consumption was examined in terms of percentage body weight.

Affinities and origin of the Antillean mammals

Research Article| December 01, 1918 Affinities and origin of the Antillean mammals W. D. MATTHEW W. D. MATTHEW Search for other works by this author on: GSW Google Scholar GSA Bulletin (1918) 29 (4): 657–666. https://doi.org/10.1130/GSAB-29-657 Article history received: 22 Aug 1918 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation W. D. MATTHEW; Affinities and origin of the Antillean mammals. GSA Bulletin 1918;; 29 (4): 657–666. doi: https://doi.org/10.1130/GSAB-29-657 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Limitations and Relationships of West Indian Mammal Faunas, Living and ExtinctIN GENERALThe indigenous land mammals of the West Indies consist of three groups: (1) Insectivora, (2) hystricomorph rodents, (3) gravigrade edentates. No perissodactyls (horses, rhinoceroses, tapirs, etcetera), no artiodactyls (peccaries, deer, antelopes, etcetera), no proboscideans (elephants, mastodons, etcetera), no true carnivores (dogs, cats, raccoons, mustelines, bears, etcetera). Nor are there any sciuromorph, lagomorph, or myomorph rodents, shrews, moles, hedgehogs, or opossums. All these large groups, most of them abundant and varied in Tertiary North America, are wholly absent. Nor do the Insectivora, rodents, or edentates include anything at all nearly allied to any North American members of the order or derivable from anything known to have inhabited North America in the later Tertiary.Most of these North American groups invaded South America in the Pliocene and are part of its later fauna. In the Miocene and early Tertiary they are not found in South America, but their place is taken by . . . This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.