Wild Diet Research Articles

The three-dimensional morphological effects of captivity.

Many captive animals are fed diets that are drastically different in mechanical properties than their wild diet. Most captive pantherines are fed a nutritionally supplemented diet consisting almost entirely of ground meat. While many zoos supplement this diet with bones, the fact remains that large captive felids are fed diets that require substantially less masticatory effort than those of their wild counterparts. The osteological effects of this dietary difference have not been fully evaluated. To this end, we compared linear measurements and 3D geometric morphometric landmarks of captive and wild lions and tigers. Using Principal Component (PC) analysis of the linear measurements, not only were the sexes and species statistically distinct, but so too was the population clearly divisible in terms of captivity status. The 3D analysis supported these findings: although the most influential variable in the sample (PC1, 21.5% of the variation) separates the two species, the second most influential contributor (PC2) to the overall skull shape is driven not by the sex differences in these highly dimorphic species, but rather by their captivity status. In fact, captivity status drives nearly twice as much of the 3D variation as sexual dimorphism (14.8% vs. 8.0% for PC2 vs. PC3). Thus the shape is influenced nearly twice as much by whether the animal was captive or wild than by whether it was male or female. If a causal relationship can be demonstrated between dietary mechanical properties and morphology, people who oversee the diets of captive carnivores should consider modifying these diets to account for not only nutritional but also the mechanical properties of a carcass-based diet as well. In addition to the husbandry implications, our analyses show the ways in which captive specimens are different than their wild counterparts – findings that have implications for morphologists when considering anatomical samples.

Comparative diet and nutrition of frugivorous and folivorous primates at the Singapore Zoo

Considerable variability in dietary and digestive strategies exists across primate taxa. Differences in wild primate diet are strongly reflected along the frugivory-folivory continuum, whereby the selection of fruits or leaves as primary diet is strongly linked to different digestive systems that optimizes the extraction of nutrients from these different food types to meet nutritional goals. Successful maintenance of wild primates in captivity require appropriate dietary husbandry to meet the different needs of these primate species. We examined the diet of six species of captive primates with primarily frugivorous or folivorous dietary management and how their nutritional intake corresponded to their provided diet of fruits/vegetables and leaves. Folivorous primates obtained major components of their diet (protein and carbohydrate) from their leave diet while frugivores obtained relatively equal proportions of these components from both food types. Folivorous primates obtained higher protein and fiber - Neutral Detergent Fiber (NDF) and Acid Detergent fiber (ADF) intake from their leave diets; and higher Non-Structural Carbohydrate (NSC) intake from their fruit diets. Frugivorous primates obtained higher NSC and lower fiber (ADF and NDF) intake from their fruit/vegetable diets. Higher fiber intake resulted in longer Transit Time (TT) for frugivores and longer Mean Retention Time (MRT) for folivores. Overall dietary NSC levels for folivores were close to the recommended upper limits for foregut fermenters; and dietary fiber levels were relatively high for frugivores. These results suggests that appropriate adjustments to the diet provided to these primates should be considered to reduce general intake of easily digestible carbohydrates by folivorous and evaluate the possible implications of high fiber diets for frugivores. Dietary husbandry for captive primates according to their dietary specializations should be considered whenever possible, within constrains of practical captive management.

Long term observations on the alimentation of wild Eastern Greek Tortoises Testudo graeca ibera (Reptilia: Testudines: Testudinidae) in Dobrogea, Romania

The wild diet of Testudo graeca ibera in Dobrogea, Romania is investigated by direct observation. A clear predominance (over 95%) of plant matter is noticed, with 25 plant species consumed. Moreover the ingestion of animal matter (carrion) as well as calcareous earth was observed.

Maintaining Coral Snakes (Micrurus nigrocinctus, Serpentes: Elapidae) for venom production on an alternative fish-based diet

American Elapid snakes (Coral Snakes) comprise the genera Leptomicrurus, Micruroides and Micrurus, which form a vast taxonomic assembly of 330 species distributed from the South of United States to the southern region of South America. In order to obtain venom for animal immunizations aimed at antivenom production, Coral Snakes must be kept in captivity and submitted periodically to venom extraction procedures. Thus, to maintain a snake colony in good health for this purpose, a complete alternative diet utilizing an easily obtained prey animal is desirable. The development of a diet based on fish is compared to the wild diet based on colubrid snakes, and assessed in terms of gain in body weight rate (g/week), longevity (weeks), venom yield (mg/individual), venom median lethal dose (LD50) and venom chromatographic profiles. The animals fed with the fish-based diet gained more weight, lived longer, and produced similar amount of venom whose biological and biochemical characteristics were similar to those of venom collected from specimens fed with the wild diet. This fish-based diet appears to be suitable (and preferable to the wild diet) to supply the nutritional requirements of a Micrurus nigrocinctus snake collection for the production of antivenom.

Infertility in the Southern White Rhino: Is Diet the Source of the Problem?

Infertility in the Southern White Rhino: Is Diet the Source of the Problem?

The impact of raw and cooked wild cocoyam (Caladium bicolor) on the performance of broiler chicks

This study was carried out to evaluate the impact of raw and cooked wild cocoyam (Caladium bicolor) on the performance of broiler chicks. Wild cocoyam corms were divided into two batches. One batch was ground raw and the other batch was cooked before grinding. Wild cocoyam meals so prepared were used to formulate 5 broiler starter diets at dietary inclusion levels of 0, 10 and 20% raw and cooked wild cocoyam respectively. 180 7-day-old Anak broiler chicks were randomly allotted to the five treatment diets in a Completely Randomized Design (CRD) and each group was further subdivided into three replicates of 12 birds. Measurements recorded included weight gain, feed intake, feed conversion and protein efficiency ratios and economics of production. Results shows significant (p<0.05) improvement in feed intake, weight gain, feed conversion ratio and PER of birds fed cooked wild cocoyam meals. Marked (p<0.05) reduction was however, obtained in feed intake and feed conversion ratio of birds fed raw wild cocoyam diets. There was no significant (p>0.05) difference between birds fed maize-based (control) and cooked wild cocoyam diets. Results of this experiment indicated that cooking improved the nutritive value of wild cocoyam since birds fed cooked wild cocoyam diets produced best results than those fed raw wild cocoyam meal and that starter broilers could tolerate up to 20% dietary inclusion level of cooked wild cocoyam without any deleterious effect. Economics of production showed that cooked wild cocoyam diets were more profitable as regards the cost of feed per kg weight gain (N) and thus cost savings (%).

Preliminary analysis of the diet of wild boar (Sus scrofa L., 1758) in Islamabad, Pakistan

During the present study, 117 wild boars (Sus scrofa) were killed to examine their stomach contents in Islamabad, Pakistan. Stomach contents were found to be correlated with feeding sites, plant material, and the nature of food material and items consumed from both cultivated and noncultivated lands. The major component of the wild boar's diet in Islamabad was garbage (58%), followed by dead animals (16%), while the rest of the consumed food comprised cereals, herbs, grasses, weeds, tree bark, etc. Wheat leaves were prominent in samples collected from December 2005 until March 2006, when wheat grains (seed formation stage) became the major part of diet until July; maize was also a part of the diet during the same period. A small quantity of tree bark and Zizyphus leaves were also found in the stomachs, and mesquite was heavily consumed in June and July. Several grasses and weeds appeared prominently in the diet during the period between August and November. The presence of garbage among other food items was highest in the stomach throughout the year.

Dietary choices by four captive slender lorises (Loris tardigradus) when presented with various insect life stages

The slender loris (Loris tardigradus) is a rare, nocturnal prosimian found only in the tropical rainforest of southern India and Sri Lanka. Little is known about their diet, though it is assumed that insects comprise a majority of their wild diet. Based on this assumption, captive lorises are offered a variety of insects or insect life stages; the species of insect or the life stage is often determined by what is easiest to buy or rear. Captive lorises at the Duke Lemur Center (DLC) were offered the opportunity to choose which life stage of mealworms (Tenebrio molito), superworms (Zophobus morio), or waxworms (Galleria mellonella) they preferred. The DLC captive lorises did not select the largest life stages of any insect offered. They preferred the larvae stage to the adult stage in all three insect species, and males and females had different insect species and life stage preferences.

Stable isotopes reveal post-release trophodynamic and ontogenetic changes in a released finfish, mulloway (Argyrosomus japonicus)

Carbon and nitrogen stable isotope ratios were analysed for hatchery-reared, recaptured and wild mulloway, Argyrosomus japonicus, to investigate temporal and growth-related changes in isotopic composition for stocked fish after release, and to evaluate changes in isotopic composition in terms of ontogenetic dietary switches. δ13C and δ15N values decreased and increased, respectively, after release. The isotope composition of released fish was distinct from wild fish until 200 days after release, but after 200 days post-release fish did not differ significantly from wild fish of similar or greater sizes. Abrupt dietary transitions from crustaceans to teleost fish (>50 cm total length (TL)) were evident in a rapid δ13C and δ15N change in wild mulloway, and δ15N was significantly greater in wild fish >65 cm TL compared with wild fish <50 cm TL. Multivariate carbon and nitrogen isotopic data were suitable for separating stocked and wild fish for up to 200 days after release, but did not separate wild fish grouped according to dietary composition. Carbon and nitrogen isotopic composition closely reflected dietary transitions and rapid adaptation by stocked mulloway to wild diets, which was evident in a high tissue turnover rate of up to 0.017 day–1. Stable isotopes are a useful tool for examining the integration of released fish into stocked ecosystems and can be used to describe convergence in the diets of wild and released fish.

The effect of weight loss on protein profiles of gastrocnemius muscle in rabbits: a study using 1D electrophoresis and peptide mass fingerprinting

The study of physiological changes occurring during selection contributes to an improved understanding of relationships leading to efficiencies in animal production. To investigate the effects of food restriction in gastrocnemius muscle protein expression, 20% weight reduction was induced in New Zealand White (meat producing) and wild rabbits, using one-dimensional gel electrophoresis and peptide mass fingerprinting. Lower expression levels of myosin heavy chains were found in the Wild Rabbits Restricted Group, while myosin light chain and alpha-crystallin proteins were not detected in restricted groups. Glyceraldeyde-3-phosphate dehydrogenase and glycogen phosphorylase expression levels were similar for all experimental groups. Phosphopyruvate hydratase beta was not detected in the wild rabbit restricted diet group. Pyruvate kinase levels were 50% lower in the New Zealand Restricted group. LIM protein detection was absent in the control New Zealand group. Results also show relevance of actin in preserving muscle structure in depressed food availability, the sensitivity of both myosin light chain and alpha-crystallin protein to restricted feed and the role of PK in the resistance of New Zealand rabbits to food restriction.

Fatty acid nutritional quality of sea urchinParacentrotus lividus(Lamarck 1816) eggs and endotrophic larvae: relevance for feeding of marine larval fish

Sea urchin eggs and larvae have been suggested as potential live prey for marine fish larval feeding. This study evaluated the fatty acid composition of Paracentrotus lividus eggs, prisms and four-armed plutei, obtained from wild and captive broodstocks fed on raw diets: maize, seaweed and a combination of maize and seaweed. Amounts of essential fatty acids (EFA) for marine fish larvae [arachidonic acid (ARA), eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA)] were determined in eggs and endotrophic larvae. ARA ranged from 3.93% in eggs from combination to 18.7% in plutei from maize diets. In any developmental stage, EPA amounts were always lower than 5% for the raw diets, and DHA showed null or trace amounts including the wild diet. Thus, broodstock-prepared diets had to be formulated based on different lipid sources (Algamac, linseed oil, cod liver oil and olive oil) in order to test eggs and larvae EFA enhancement. EFA improvement was possible for all tested prepared diets. Algamac diet lead to superior EFA enhancement mainly in DHA (7.24%, 4.92% and 6.09% for eggs, prisms and plutei, respectively) followed by cod liver oil diet. Only these two lipid sources should be considered for prepared broodstock diets in order to obtain suitable live prey for fish larval feeding.

Diet Composition and Feeding Periodicity of Wild and Hatchery Subyearling Chinook Salmon in Lake Ontario

Diel feeding periodicity, daily ration, and diet composition of wild and hatchery subyearling Chinook salmon Oncorhynchus tshawytscha were examined in Lake Ontario and the Salmon River, New York. The diet of wild riverine salmon was composed mainly of aquatic invertebrates (63.4%), mostly ephemeropterans (25.8%), chiromomids (15.8%), and trichopterans (8.3%). The diet of riverine Chinook was more closely associated with the composition of drift samples rather than bottom samples, suggesting mid-water feeding. In Lake Ontario terrestrial invertebrates were more important in the diet of hatchery Chinook (49.0%) than wild salmon (30.5%) and diet overlap between hatchery and wild salmon was low (0.46%). The diet of both hatchery and wild Chinook salmon was more closely associated with the composition of mid-water invertebrate samples rather than benthic core samples, indicating mid-water and surface feeding. Hatchery Chinook salmon consumed significantly less food (P < 0.05) than wild Chinook salmon in the lake and in the river, and wild salmon from Lake Ontario consumed more food than wild salmon in the Salmon River. Peak feeding of wild Chinook salmon occurred between 1200–1600 hours in Lake Ontario and between 1600–2000 hours in the Salmon River; there was no discernable feeding peak for the hatchery Chinook in Lake Ontario. Hatchery Chinook salmon also had the least diverse diet over the 24-hour sample period. These results suggest that at 7 days post-stocking hatchery Chinook salmon had not yet fully adapted to their new environment.

Differences in the digestive organ morphology of captive and wild Brown Teal Anas chlorotis and implications for releases

The digestive tract of many animals is morphologically flexible and can adjust over time to make the most efficient use of the foods available. Differences between captive and wild diets often cause large differences in the gut morphology of captive and wild birds. This is potentially an issue when captive-bred birds are used to establish or supplement populations in the wild, such as in the Brown Teal Anas chlorotis, an endangered duck endemic to New Zealand. We compared the size and mass of the digestive organs (proventriculus, gizzard, small intestine, caeca, rectum and liver) of 57 wild, eight captive and four captive-bred released Brown Teal. Captive Brown Teal had much shorter and lighter small intestines and caeca than wild Brown Teal. These differences could reduce the ability of captive-bred teal to efficiently digest a wild diet in the weeks following release, and are likely to contribute to the number of released teal found dead in extremely poor nutritional condition. Increased fibre and diversity in the captive diet together with supplementary feeding post-release are recommended to improve the survival of captive-bred Brown Teal released to the wild.

Nutritional ecology of elephants in Kibale National Park, Uganda, and its relationship with crop-raiding behaviour

This study investigated the nutritional ecology of forest elephants in Kibale National Park, Uganda relative to crop-raiding behaviour, and examined nutritional differences between crops and food consumed by wild elephants. An index of dietary nutrient concentration was determined by quantifying the species and parts of plants consumed along feeding trails, collecting food items, and analysing foods for energy, fibre, protein, minerals and secondary compounds. Frequency of crop raiding was quantified over 13 mo. Energy and protein concentration was within suggested levels, but concentrations of several minerals, particularly sodium, were low relative to requirements based on captive elephants and values reported for other wild populations. The very low sodium concentrations of Kibale elephant diets and low availability of alternative sodium sources, such as soil or water, suggest that sodium drive is very likely in this population. Crops consumed by Kibale elephants had higher Na concentrations and lower concentrations of fibre and secondary compounds than wild diets. The known attraction of elephants to mineral sources throughout their range and the low mineral concentration of leaves, fruits, bark, and stems consumed by forest elephant in this study suggest that mineral nutrition is likely to be an important factor driving elephant behaviour and patterns of habitat use.

Is alpha-Pinene a Substrate for Permeability-Glycoprotein in Wood Rats?

alpha-Pinene is the dominant monoterpene in Juniperus monosperma. Wood rat species in the genus Neotoma that consume J. monosperma vary in their inclusion of it in their wild diet and in their tolerance of whole J. monosperma or alpha-pinene in laboratory feeding trials. A proposed mechanism for variable tolerance is a difference in absorption of alpha-pinene from the small intestine that is mediated by the intestinal transporter permeability glycoprotein (Pgp). To determine if alpha-pinene is a Pgp substrate, we tested whether it can competitively inhibit Pgp and thereby increase the accumulation of a known Pgp substrate (digoxin) in (1) everted sleeves of small intestine from Neotoma stephensi, a juniper specialist, N. albigula, a sympatric generalist that consumes juniper, N. cinerea, a more distantly related generalist, and Sprague-Dawley rats, and (2) in Caco-2 cells that over express Pgp. We also measured Pgp ATPase phosphate production in transfected insect membrane vesicles exposed to alpha-pinene. We found no significant increase in digoxin accumulation with competitive inhibition experiments, and no increase in phosphate production with transfected membranes, at any concentration of alpha-pinene up to 100 muM. To test whether other compounds in juniper affect Pgp activity, we acclimated five N. stephensi to a juniper diet for 5 d, but found no significant effect compared to animals on control diet. Our data suggest that alpha-pinene is not a Pgp substrate.

Using stable isotope ratios as a tracer of feeding adaptation in released Japanese flounder Paralichthys olivaceus

Release‐recapture experiments were conducted to examine temporal changes of the carbon and nitrogen stable isotope (δ13C and δ15N) ratios in the muscle tissue of artificially produced Japanese flounder Paralichthys olivaceus, juveniles. About 9000 juveniles (mean ± s.d. 43·3 ± 5·2 mm in standard length and 1·07 ± 0·37 g, n = 15) were released in each of three coastal areas: Chojagasaki, Arasaki and Jogashima with different geographical conditions, along Sagami Bay, Pacific coast of central Japan. Recapture efforts were made on 4, 11, 18, 40 and 55 days after the release. The stable isotope ratios, RNA:DNA ratio, stomach content mass (per body mass Msc) and condition factor (K) of recaptured individuals were measured. The mean ± s.d. δ13C and δ15N values (n = 15) were −18·3 ± 0·2‰ and 12·2 ± 0·2‰, respectively at the release. Wild Japanese flounder juveniles were captured only in Chojagasaki, and the δ13C and δ15N values (n = 6) were −14·0 ± 0·4‰ and 13·2 ± 0·7‰, respectively; these values were considered to represent the wild diet. Nutritional conditions of the released and recaptured juveniles as determined by the RNA : DNA ratio, MSC and K were indicated to be the best in Chojagasaki, in which the stable isotope ratios gradually shifted towards and reached the wild values within 40 days. This result along with stomach content analyses suggested that the released juveniles had acquired a wild feeding habit. In Arasaki and Jogashima, nutritional conditions of the recaptured juveniles were poorer, with no clear changes in the stable isotope ratios. Greatly varied stable isotope ratio values were observed in the juveniles recaptured in Chojagasaki 11 days after the release, ranging from the release levels to the wild levels. The extent of changes in the stable isotope ratios had a positive correlation to the RNA : DNA ratio and K of these juveniles (r = 0·87, n = 10 and r = 0·83, n = 18, respectively). The analyses of stable isotope ratios coupled with nutritional condition were considered to be an effective tool to examine post‐release feeding adaptation of Japanese flounder juveniles.

Variance in isotopic signatures as a descriptor of tissue turnover and degree of omnivory

Summary Diet analyses using C and N stable isotopes commonly focus on mean isotopic signatures; however, isotopic variance among individuals is likely to also contain useful information including details of omnivory. Changes in isotopic signature as a result of dietary shifts are not instantly manifest in the isotopic signature of consumer tissues, but lagged over a period of time required for equilibration. Tissue turnover times have not previously been described in terms of variance in isotopic signature among individuals, and variance among individuals following equilibration with a constant diet is limited. Temporal changes in δ15N and δ13C variance in juvenile European Sea Bass (Dicentrarchus labrax) muscle, heart and liver were monitored following a shift from a wild diet to two single‐source diets administered under seminatural conditions in captivity. Exponential decay functions of the standard deviation of δ15N and δ13C among individuals were used to model changes in variance over time. All tissues exhibited a similar rate of tissue turnover using variance. However, variance among individuals within tissue types differed once fishes were equilibrated with the laboratory diet. The coefficients of variation of δ13C and δ15N were smallest in muscle and greatest in liver and greater among sampling dates than within. Analysis of δ15N and δ13C in different tissues will not therefore provide equivalent power to detect differences in diet or to track changes in patterns of omnivory. Analysis of omnivory should be restricted to variance from a single tissue type. Of the tissues considered here, white muscle is most appropriate for this purpose. Variance estimates derived here provide minimum values expected for a highly specialist feeding population. Departure from these values can be used to describe the degree of omnivory within a population.

Taught by animals: how understanding diet selection leads to better zoo diets

Wild animals invariably obtain their nutrient requirements, regulate their ingestion of toxins and even self-medicate. This review suggests that, while size and morphology dictate gross diet, the ability to select a diet is learnt. Animals learn to distinguish nutritious foods from less beneficial or toxic items through the positive and negative consequences of ingestion. In this process, early life experiences appear to be critically important. Zoo animals can rarely be provided with their wild diets and caretakers substitute nutrients from other sources. Thus, a suitable range of ingredients should be provided to give the animals a stimulating and nutritious diet that ensures excellent health.

Can proboscis monkeys be successfully maintained in captivity? A case of swings and roundabouts

AbstractAlthough most western zoos have experienced difficulties in maintaining proboscis monkeys, the Singapore Zoo has managed to sustain a social group of proboscis monkeys housed in a large naturalistic exhibit since 1998. Within 3 years after the monkeys were brought to the zoo, five offspring were produced, all of which survived. Natural forest vegetation from 20 plant species was provided along with a staple diet of about seven different species on a daily basis. The calcium and sodium contents of the plant items consumed by monkeys in the Singapore Zoo were similar to those in the diet of wild proboscis monkeys in Borneo. However, the levels of other minerals, such as iron, magnesium, manganese, potassium, zinc, and phosphorus, were significantly lower in the natural vegetation consumed by the monkeys compared to the wild diet. Food supplements such as primate biscuits, cod liver oil, boiled egg, multivitamins, and mineral syrup further ensured a more balanced diet for the captive monkeys. The data presented here show that zoos can maintain these rare Colobine monkeys successfully by provide them with a natural diet, along with appropriate husbandry and hygiene practices, minimal human interference, and applied nutritional science. The husbandry and nutritional management model presented in this paper could be of use to other institutions around the world. Zoo Biol 23:533–544, 2004. © 2004 Wiley‐Liss, Inc.

Improving Health Care Locally and Globally

<h3>ABSTRACT</h3> Poison frogs bioaccumulate alkaloids for chemical defense from their arthropod diet. Although many alkaloids are accumulated without modification, some poison frog species can metabolize pumiliotoxin (PTX <b>251D</b>) into the more potent allopumiliotoxin (aPTX <b>267A</b>). Despite extensive research characterizing the chemical arsenal of poison frogs, the physiological mechanisms involved in the sequestration and metabolism of individual alkaloids remain unclear. We first performed a feeding experiment with the Dyeing poison frog (<i>Dendrobates tinctorius</i>) to ask if this species can metabolize PTX <b>251D</b> into aPTX <b>267A</b> and what gene expression changes are associated with PTX <b>251D</b> exposure in the intestines, liver, and skin. We found that <i>D. tinctorius</i> can metabolize PTX <b>251D</b> into aPTX <b>267A</b>, and that PTX <b>251D</b> exposure changed the expression level of genes involved in immune system function and small molecule metabolism and transport. To better understand the functional significance of these changes in gene expression, we then conducted a series of high-throughput screens to determine the molecular targets of PTX <b>251D</b> and identify potential proteins responsible for metabolism of PTX <b>251D</b> into aPTX <b>267A</b>. Although screens of PTX <b>251D</b> binding human voltage-gated ion channels and G-protein coupled receptors were inconclusive, we identified human CYP2D6 as a rapid metabolizer of PTX <b>251D</b> in a cytochrome P450 screen. Furthermore, a CYP2D6-like gene had increased expression in the intestines of animals fed PTX, suggesting this protein may be involved in PTX metabolism. These results show that individual alkaloids can modify gene expression across tissues, including genes involved in alkaloid metabolism. More broadly, this work suggests that specific alkaloid classes in wild diets may induce physiological changes for targeted accumulation and metabolism.