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Insoluble grit In the wild, herbivorous birds mainly eat plant-like material and/or seeds. To be able to digest this, the seed hulls and plant cell walls must first be destroyed in the gizzard. Naturally, birds often consume small non-digestible pebbles for this. As an alternative to these stones, insoluble grit is fed . In captivity, birds are mainly fed easily digestible pellets instead of plant-like material and/or seeds. As a result, these birds have little or no need for insoluble grit. In addition, birds can also take in stones themselves if they are (partially) kept outside. For birds in captivity that do eat a lot of plant-like material and/or seeds, it is recommended to add insoluble grit. Soluble grit Birds that are fed pellets are generally provided with sufficient minerals such as calcium. However, there are a number of birds that have an extra need for calcium, such as growing birds and laying birds. In these situations, soluble grit is often supplemented. Special pellet diets with a higher percentage of calcium are also available for these birds. Research has shown that birds have the capacity to self-regulate their calcium intake. So they will not quickly absorb an excess of calcium. It is therefore recommended that a small percentage of the diet consists of soluble grit. This is also part of the diet of many birds in the wild. There are different types of soluble grit such as sepia, oyster shell, limestone (calcium carbonate), marble (crystalline limestone) and gypsum (calcium sulfate).
Hibernation is a state of minimal (metabolic) activity. When an animal is in a state of hibernation during the summer, it is called aestivation or summer sleep. In the past, the concept of hibernation was based on an absolute drop in body temperature (often more than 32°C). Today, this is based on the decline in metabolism. During hibernation, various processes in the body slow down: body temperature, metabolism, respiratory rhythm and heart rhythm. The benefit of hibernation is that an animal can survive during periods of food scarcity (such as winter) without having to spend a lot of energy gathering food. During hibernation, body fat is mainly used as an energy source. This fat is stored during the active period of the year. In addition, some animal species (such as the arctic ground squirrel) can recycle nutrients in the body. Research has shown that this species can break down its muscle fibers during hibernation, thereby releasing nitrogen. This nitrogen can be converted into amino acids and then into proteins, which keeps body tissue intact ( source ). The length of hibernation depends on the species, ranging from a few days to many months. Some animals sleep during the entire hibernation, while others sleep for broken periods. This is due to the different types of hibernation: Mandatory hibernation These are animals that are in hibernation at fixed times every year, regardless of the ambient temperature and amount of food. These species undergo a 'traditional' hibernation: a body state in which the body temperature drops sharply along with the breathing and heart rhythm. Species that fall into this group include: reptiles, amphibians, bats, hedgehogs, (many) rodents and some insectivores. Optional hibernation These are animals that are only in hibernation due to environmental stressors, such as temperature, food shortage or both. Species within this group undergo both 'traditional' and 'untraditional' hibernation, depending on their body temperature or metabolic activity. Species that belong to this group are: some monkeys (e.g. dwarf lemurs), prairie dogs and bears. Bears are wrongly thought to be a 'traditional' hibernation even though this concerns a winter rest; the heart rate does slow down, but the body temperature remains fairly constant. A bear can therefore easily be woken up. Hibernation in captivity It is not favourable for a zoo to have no visible animals for a long period of the year. However in captivity, true hibernation is rare for animals. Often the duration of the hibernation is then greatly reduced from a few months to only a few weeks. As a result, an animal's diet can also deviate from its natural diet. To compensate for this, zoos often have a special 'bulk' program in the months before natural hibernation. This allows the animals to store energy reserves in the body to be consumed during these shortened hibernation periods. In addition, more and more seasonal diets are being used to imitate the natural variation in the diet. In 2021, Marcus Clauss gave a presentation ( link ) on the work of Charles Robbins discussing the concept of seasonal diets. To summarize, both the diet composition and amount can be adjusted to mimic different seasons. Two examples of this can be seen in the charts below for different bear species. By feeding this way, it simulates the availability of food throughout the year. Source: ( link ) A practical example of this is a study from the San Diego Zoo ( link ). Here, the goal was to feed bears more seasonal diets to better mimic seasonal physiological changes. After a year, the bears showed twice as much weight variation, which is more in line with natural variation. Source: ( link ) Although this concept is emerging, it is even more important to look at the individual animal. Always adjust the diet and feeding frequency to the individual. In addition, the charts above are just examples and the ideal diet depends on the species and individual.
We have whole rabbits available in all sizes. In the overview below it is easy to compare the differences between these categories:
We have a broad assortment of supplements. To make it easier to compare these supplements we have made an overview. In this overview you will find all supplements that we offer for marine mammals. All brands have a different system of dosing: Kasper Faunafood: The supplements of Kasper Faunafood have an extensive feeding advise on the data sheets of each supplement. This advice is formulated per category of body weight. To make it easier to compare we have converted this; on average this advise is equal to 1 tablet per 2,5 kg fish. Mazuri: The Marine Mammal supplement of Mazuri is dosed as 1 tablet per 2,3 kg fish. DK Zoological: The Fish Eater Liquid of DK Zoological is dosed as 1 ml per 1 kg fish. In the first table (table 1) you will find an overview of the nutrients in each supplement. These are the nutritional additives per tablet. In table 2 you will find a converted overview of the nutritional additives per 1 kg fish (when feeding advice is followed). Table 1 Nutritional additives per tablet Table 2 Nutritional additives per 1 kg fish (when feeding advise is followed)
Shark supplements We have a broad assortment of supplements. To make it easier to compare these supplements we have made an overview. In this overview you will find all supplements that we offer for sharks. All brands have a different system of dosing: Kasper Faunafood: The Shark supplement of Kasper Faunafood has an extensive feeding advise on the data sheet. This advice is formulated per category of body weight. To make it easier to compare we have converted this; on average this advice is equal to 1 tablet per 2,5 kg of fish. Mazuri: The Shark supplement of Mazuri comes in two sizes, the 0,2 g tablet is dosed per 28 g fish and 1,5 g tablet is dosed per 226 g fish. In the first table (table 1) you will find an overview of the nutrients in each supplement. These are the nutritional additives per tablet. In table 2 you will find a converted overview of the nutritional additives per 1 kg fish (when feeding advice is followed). Table 1 Nutritional additives per tablet Table 2 Nutritional additives per 1 kg fish (when feeding advise is followed)
The sizes of our different fish species are shown in this overview. A guideline is also given for which animal species they are suitable:
Introduction Giraffes (Giraffa camelopardalis) are browsers, primarily feeding on leaves from trees and shrubs, with a preference for acacias and other leafy plants4, 9. Foraging is their primary activity, essential for maintaining their bodies. Rumination is also crucial to giraffes' natural behavior, aiding in the effective digestion of food, especially breaking down insoluble carbohydrates like fiber found in plant cell walls3. In captivity, fulfilling giraffes' nutritional needs is challenging, particularly during winter when natural food sources diminish. Limited availability of fresh leaves and branches leads to provision of mainly roughage, alfalfa hay, and low-fiber pellets, which may not adequately stimulate natural behaviors, potentially resulting in abnormal behaviors like oral stereotypies1, 2, 7, 8, 9, 10. Increasing fiber content in the diet can promote natural behaviors, including longer rumination periods and reduced abnormal behaviors3,6. The development of "DK Dried Browse Mulch" by Kiezebrink offers a promising nutritional supplement for giraffes, resembling their natural diet and rich in dietary fiber5. This could potentially increase foraging and rumination time while reducing abnormal behaviors in captive giraffes. Methods & Materials • The research, carried out at Dierenpark Amersfoort in the Netherlands, spanned from December 11th, 2023, to January 14th, 2024, focusing on the behaviour of four male giraffes. • Daily rations based on giraffes weighing 900 kg - Diet 1: 4.4 kg of browser pellets - Diet 2: 4.4 kg of browser pellets + 2 kg of DK Dried Browse mulch. Both rations were divided into two feeding sessions. • For 10 days per diet, instantaneous scan sampling at 30-second intervals during morning feedings monitored foraging behavior. • For 8 days per diet, continuous focal sampling observed rumination and abnormal behaviors after morning feedings for one hour per giraffe per day. • Alfalfa hay, browse, and ad libitum water were available throughout the day. • Linear Mixed Models analyzed the impact of DK Dried Browse mulch on foraging and rumination behavior. • Due to limited data, oral stereotypies are not statistically tested. A simple descriptive statistics is used to compare oral stereotypies before and after adding DK Dried Browse mulch, specifically focused on 'licking unnatural objects'. Results & Discussion • Giraffes spend significantly more time foraging during the morning feeding with Diet 2 compared to Diet 1 (Table 1). The addition of DK Dried Browse mulch to Browser pellets likely increased foraging time (p < 0.05). • Giraffes spend significantly more time ruminating with Diet 2 compared to Diet 1 (Table 1). The addition of DK Dried Browse mulch to Browser pellets likely increased rumination time (p < 0.05). • After the addition of DK Dried Browse mulch to Browser pellets, the duration of licking unnatural objects is halved, suggesting a potential alleviation of oral stereotypies (Figure 1). However, this was not statistically tested. Table 1*: Comparison of Average Duration of Foraging, Rumination, and Oral Stereotypies between Two Diets: Browser Pellets (Diet 1) and Browser Pellets with the Addition of DK Dried Browse Mulch (Diet 2), Highlighting Differences in Foraging and Rumination Times. Figure 1*: Difference in average duration of foraging, rumination and oral stereotypies between Browser pellets (Diet 1) and Browser pellets with an addition of DK Dried Browse mulch (Diet 2) *For this study on the impact of DK Dried Browse mulch on the foraging, rumination, and abnormal behaviors of captive giraffes, we used a base diet comprising Kasper Natural Browser (10mm) and Boskos Browser. • The study provides valuable insights, but factors like limited visibility and sample size could affect interpretation. Changes in mulch quantity and the presence of finely ground acacia fibers in DK Dried Browse mulch could also impact outcomes. Additionally, solely daytime observations may limit comprehensive understanding; nocturnal observations could provide supplementary insights. Conclusion • Supplementing Browser pellets with DK Dried Browse mulch positively affects the duration of foraging, rumination, and abnormal behaviors in giraffes. • Giraffes receiving DK mulch spend significantly more time foraging and rumination while exhibiting reduced abnormal behaviors, particularly in licking unnatural objects. • Further studies are necessary to evaluate the long-term effects of this dietary adjustment and explore other potential factors influencing behavioral changes. References Appleby, M. C., & Lawrence, A. B. (1987). Food restriction as a cause of stereotypic behaviour in tethered gilts. Animal Production 46: 104-110. Bashaw, M. J., Tarou, L. R., Maki, T. S., & Maple, T. L. (2001). A survey assessment of variables related to stereotypy in captive giraffe and okapi. Applied Animal Behaviour Science, 73(3), 235–247. https://doi.org/10.1016/s0168-1591(01)00137-x Baxter, E., & Plowman, A. B. (2001). The Effect of Increasing Dietary Fibre on Feeding, Rumination and Oral Stereotypies in Captive Giraffes (Giraffa Camelopardalis). Animal Welfare, 10(3), 281–290. https://doi.org/10.1017/s0962728600024052 Davis, D. E., Dagg, A. I., & Foster, J. B. (1978). The Giraffe. Its Biology, behavior and ecology. The Journal of Wildlife Management, 42(3), 711. https://doi.org/10.2307/3800862 DK Zoological. (2023). DRIED BROWSE MULCH. Geraadpleegd op 5 december 2023, van https://www.kiezebrink.eu/public/attachments/Droogvoer/DK%20Zoological/DK%20Dried%20Browse%20Mulch.pdf Hummel, J., Clauß, M., Baxter, E., Flach, E., Johanson, K., Fidgett, A., Eulenberger, K., Hatt, J., Hume, I. D., Janssens, G., & Nijboer, J. (2006). The influence of roughage intake on the occurrence of oral disturbances in captive giraffids. In Filander eBooks (pp. 235–252). https://doi.org/10.5167/uzh-3523 Hummel, J., Zimmermann, W., Langenhorst, T., Schleussner, G., Damen, M., & Clauss, M. (2006). Giraffe husbandry and feeding practices in Europe. Results of an EEP survey. In: 6th Congress of the European Association of Zoo and Wildlife Veterinarians, Budapest (Hungary). https://doi.org/10.5167/uzh-3562 Koene, P. (1999). When feeding is just eating. How do farm and zoo animals use their spare time? In D. van der Heide, E. A. Huisman, E. Kanis, J. W. M. Osse, & M. W. A. Verstegen (Reds.), Proceedings 5th Zodiac Symposium Wageningen, The Netherlands (pp. 13-19). Okabe, K., Kawamura, A., Fukuizumi, H., Ishiuchi, K., & Kase, C. (2019). Does oral stereotypy in captive giraffes decrease by feeding them evergreens and barks in winter. Animal Behaviour and Management, 55(4), 165–173. https://doi.org/10.20652/jabm.55.4_165 Terlouw, C. E. M., Lawrence, A. B., & Illius, A. W. (1991) Influences of feeding level and physical restriction on the development of stereotypies in sows. Applied Animal Behaviour Science 28: 135 – 152.
We have a broad assortment of supplements. To make it easier to compare these supplements we have made an overview. In this overview you will find all supplements that we offer for marine birds. All brands have a different system of dosing: Kasper Faunafood: The Fish eating animals supplement of Kasper Faunafood has an extensive feeding advise on the data sheet. This advice is formulated per category of body weight. To make it easier to compare we have converted this; on average this advice is equal to 1 tablet per 2,5 kg of fish. Mazuri: The Small Fish eating bird supplement of Mazuri is dosed as 1 tablet per 226 g fish. The Large Fish eating bird supplement of Mazuri is dosed as 1 tablet per 1,1 kg fish. DK Zoological: The Fish Eater Liquid of DK Zoological is dosed as 1 ml per 1 kg fish. In the first table (table 1) you will find an overview of the nutrients in each supplement. These are the nutritional additives per tablet. In table 2 you will find a converted overview of the nutritional additives per 1 kg fish (when feeding advice is followed). Table 1 Nutritional additives per tablet Table 2 Nutritional additives per 1 kg fish (when feeding advise is followed)
Within the animal kingdom, three distinctions can be made based on the diet: herbivores, carnivores and omnivores. The word ‘-vores’ stems from the Latin word - vorus: eater. Besides this, the words ‘herbi’, ‘carni’ and ‘omni’ stem from the Latin words: herba : plant caro : meat omnis : all In general, all animal species, from fish to birds, can be placed in a category. While some species are easily placed within a group (i.e. zebra), others may be more difficult as their diet is closely related to two groups (i.e. dwarf mongoose). In addition to this, it can also be the case that a young animal is herbivorous while it gets more omnivorous as the animal grows older. The body adapts itself to digest food as efficiently as possible. For this reason, physiological differences occur between herbivores, carnivores and omnivores, which can mainly be seen in the digestive system. In general, animal material is considered as easily digestible while plant material is seen as difficult to digest. Therefore, the digestive system of herbivores is most complex while that of carnivores is least complex. Compared to terrestrial animals, birds are an exception in terms of digestive system. Adaptions in digestive system The primary function of the digestive system is to break down food and moving the nutrients towards cells in the body. In turn, they can use these nutrients for building tissues or energy production. In order to do this efficiently, adaptations have occurred within the digestive system of herbivores, carnivores and omnivores. The biggest differences can be seen in the teeth, the stomach and intestines. Teeth The digestive system start at the mouth, where the teeth grind the food. The teeth have adapted through evolution based on the food that is being eaten. For example: as a result of a plant-based diet, herbivores have large flat molars that help grind fiber-rich material. In comparison, the teeth of carnivores has well-developed incisors and canines; which are used for catching prey and tearing meat. Omnivores have mixed teeth compared to herbivores and carnivores, which can be used for both grinding as well as tearing. In this way, each animal has teeth that are specialized for their specific natural diet (see image). As a result, it is often possible to identify an animal just by looking at the skull and the placement of the teeth. Source adjusted from: https://drbillspetnutrition.com/carnivores-omnivores-herbivores/ Stomach After the teeth, food passes through the oesophagus into the stomach. Here the food is stored, kneaded and mixed with gastric juices that aid in further digestion. The stomach can differ significantly between carnivores, herbivores and omnivores. Carnivores have a relatively simple stomach because the material that they consume is digested more easily compared to plant material. In herbivores, the stomach is more complex because the energy in plant material is difficult to access. Therefore, a special mechanism has evolved to 'release' this energy: fermentation. During the fermentation process, bacteria break down difficult-to-digest material, after which the nutrients can be further absorbed by the body. Fermentation can occur in two places: the stomach and the large intestine. Stomach fermentation mainly occurs in ruminants (such as giraffes or deer) and some monkey species. Although fermentation in the stomach is rare in omnivores, their stomach is better able to process plant material than a carnivore stomach. Intestinal fermentation takes place in the large intestine of animals with one stomach compartment (non-ruminants), such as most herbivores, and many omnivores also have functions of this. Small intestine After the stomach, food is gradually moved to the small intestine, where it is largely hydrolysed and absorbed. Here, the biggest differences can be seen in the length of the intestine. This provides information about the time the food slurry is in the gut to be absorbed. Easily digestible material takes less time to be absorbed and therefore the gut is also shorter, as in carnivores. The opposite is true for hard-to-digest material, such as in omnivores and herbivores. Large intestine After the small intestine comes the large intestine. This is where resorption and fermentation takes place. This form of fermentation takes place in carnivores, omnivores and herbivores with fermentation in the stomach. However, it is a lot better developed in herbivores with intestinal fermentation. The image below shows how in kangaroos (stomach fermentation) the stomach is better developed than the large intestine. The pony (intestinal fermentation) shows how the large intestine is considerably better developed than the stomach. Because fermentation in the gut is less efficient than fermentation in the stomach, these animals have to consume larger amounts of food to meet their energy needs. Source adjusted from: https://www.sciencedirect.com/science/article/pii/S1095643308009914 Conclusion The digestive system of herbivores is more complex compared to carnivores and omnivores, enabling them to consume difficult-to-digest material, such as plants. An omnivore's digestive system has adapted to be very flexible, and therefore they can consume a wide range food items. Carnivores have the simplest digestive system, which makes them less flexible in terms of the diversity of their food. In addition, they are more dependent on a specific diet because otherwise nutritional deficiencies can arise.
Compared to terrestrial animals, birds have a different digestive system. Throughout evolution, their bodies have adapted to be as light as possible as this helps with flying. An explanation of the general digestive system of birds is given below. Beak First of all, birds take in food using their beaks. The beak is adapted to the type of food that is mainly eaten (see picture). Inside the beak, the food is partially ground or swallowed whole. There are also birds that drop their food from the air or smash it against a hard surface to make it easier to swallow. The tongue ensures that the food moves towards the esophagus, after which the food enters the crop. Adapted from: https://en.wikipedia.org/wiki/Beak ( not to scale ) Crop The crop has several functions. As many birds naturally eat as much as possible per feeding moment, the food is stored in the crop. The food is stored and gradually sent to the stomach. In addition, the liquids in the crop ensure soaking of the food and a 'pre-fermentation', which improves the digestibility. Adult birds feed their young with food that has soaked in the crop, so that it is easier to digest. After the crop, the food goes to the stomach. Stomach Birds have two stomach compartments: the proventriculus and gizzard. First the food enters the proventriculus, which is similar to the stomach of many mammals. In the proventriculus, mucus, hydrochloric acid and pepsinogen are released into the food mash. These substances aid in the digestion of food. In carnivorous birds, this part of the stomach is the most developed because animal material such as bone has to be broken down here. The food slurry then ends up in the gizzard. The gizzard consists of a thick muscle wall that slides past each other. By means of sliding and using grit, food is ground (<1mm) so that the nutrients can be absorbed in the intestines. Grit can be classified into insoluble (stomach grit) and soluble. Insoluble grit is not digestible and therefore has a grinding function in the gizzard. In contrast, soluble grit is digestible and does not function as a grinding component but as a mineral (mainly calcium). Soluble grit is especially important for birds that have a higher calcium requirement, such as laying birds and growing birds. Intestinal tract When comparing the small intestine, there are little differences compared to terrestrial animals. The functions are also the same: hydrolysing and absorbing nutrients. The large intestine is where the difference really shows again; in birds this consists of three parts: caeca, colon (rectum) and cloaca (see picture). The caeca plays a role in fermenting fiber and absorbing nutrients and water. Only dissolved fibers can end up in the caeca and thus be fermented. Insoluble fiber is largely excreted. The colon is mainly for resorption and transport to the cloaca. Finally, the cloaca provides storage of faeces and extra resorption. Reflux Then there is another important principle in the digestion of birds: reflux. This is a mechanism that enables food material to be 'pushed' back to a previous compartment of the digestive system. The function of reflux is that nutrients are better absorbed. This is because the time in the digestive system is longer. This leaves more time for e.g. absorption, mixing and grinding. In addition, fibers can be pushed back into the caeca to still be fermented. Reflux can occur in the following places: Gizzard > proventriculus End of small intestine > beginning of small intestine Colon > ceaca Conclusion Compared to land animals, birds have a different type of digestive system. Next to this, also between birds significant differences can be seen in digestive system as they also adapted to their environment and diet. For this reason, birds can also be classified into a category such as herbivore, carnivore or omnivore.
A recent study reveals the risks of excessive vitamin D levels in the diets of anteaters and armadillos. In both species, symptoms such as weight loss, loss of appetite and vomiting became apparent. During the study it appeared that the vitamin D content in the feed was much higher than indicated on the product sheet (6,000 IU/kg). As a result, the animals have received too much vitamin D for a longer period of time, this is a fat-soluble vitamin and can therefore be dangerous in the event of an overdose because the animals cannot dispose of it. Our DK Insectivorous diet also contains vitamin D (2,500 IU/kg). We have added this because the insects that are the natural diet of these species also contain vitamin D. Little research is available, but based on this data it is assumed that anteaters do need vitamin D in their diet. The level of vitamin D that we add is a safe level and will therefore not lead to shortages or overdose in the animals. Cole et al. (2020) Hypervitaminosis D in a giant anteater ( Myrmecophaga tridactyla ) and a large hairy armadillo ( Chaetophractus villosus ) receiving a commercial insectivore diet. J Zoo Wildl Med, 17;51(1)245-248 https://pubmed.ncbi.nlm.nih.gov/32212572/ Oonincx et al. (2018) Evidence of vitamin D synthesis in insects exposed to UVb light. Scientific reports, 8, 10807 https://www.nature.com/articles/s41598-018-29232-w
In general, Birds of Prey hunt and eat a variety of animal matter. Prey items such as birds, small mammals, fish, reptiles, insects and amphibians are consumed. For Bird of Prey keepers and caretakers, it is important to know the natural diet of their birds. The challenge is to approach and treat this diet in the best possible way. Day old chickens Day old chicks are the staple diet for many birds of prey in captivity. It is a relatively cheap food  source and they are fairly nutritiously complete. The egg yolk, for instance, is a highly nutritious package full of fat-soluble vitamins such as vitamin A and vitamin E. However feeding day old chicks with egg yolk every day might cause problems. It is therefore advised that half of the day old chicks that are fed, should be de-yolked. Rodents Most mammals given as food to birds of prey are rodents such as rats and mice. Hamsters and guinea pigs are less readily available, but are also good to offer. Care has to be taken when feeding big mammals to smaller birds as the big bones can be a danger and should be broken up. In their greedinessâ they can ingest big bone pieces which can easily get stuck in their crop or oesophagus. Rodents are an ideal prey source to vary the birds diet. Quail and pigeon Birds of prey are often fed with quail or pigeon. These prey items resemble the natural diets of many birds of prey, especially falcons.. When using these prey items as food, caution should be taken regarding the transmission of bird specific diseases. Removing the head and the digestive system can minimize the risks of transmissions of pathogens. The freezing process also kills some pathogens. Often only certain parts of the prey items are used as food, which results in the necessity to supplement it with a vitamin and mineral supplement. Other meat products Other meat products such as chicken or turkey necks can be a good source to give some extra variation and enrichment. Minced beef or cow heart are often used when hand feeding chicks. Be aware that these products are not nutritionally balanced and can only be used as part of a diet. Ask your nutritionist or your veterinarian on how to implement these products in the diet. Good nutrition in birds is of great importance. Michiel Derks, nutritionist at Kiezebrink, has together with veterinarian Frank Verstappen and animal nutrition expert Joeke Nijboer developed a booklet containing a lot of information on the responsible feeding of birds of prey and owls. This useful booklet can be ordered online in our web shop.
We have a wide selection of insect available. In general insects are a good source of animal protein for your animals, however not every insects has the same nutritional value. We have made an overview of the macro nutrient analysis of some insect species to make an easy comparison. Source: Topinsect, 2023
Traditional fruits (also known as commercial fruits) are commonly fed to animals within zoos. However, in zoo literature, the feeding of such commercial fruits to herbivores, omnivores and especially primates is discouraged. This is because these fruits are cultivated to please the human palate, thereby referring to both the physical appearance as well as its nutritional composition. Often commercial fruits have a lot of pulp, few seeds and a sweet flavour. This flavour is due to the low fibre content and high concentrations of sugar in commercial fruits, which is also why we like to eat them. Contrastingly in the wild, frugivorous animals eat reproductive parts of plants that are present in their natural habitat, often referred to as ‘wild fruits’. Their appearance and nutritional composition largely differs from commercial fruits. For instance, they contain much less sugar and more fibre. Therefore, the natural diet of many animals contains amounts of fibre that exceed the level in commercial fruits. Besides this, the combination of a high sugar and low fibre content in commercial fruits in comparison with wild fruits, makes them very rich in energy. This increases the risk of developing obesity, especially since many captive animals cannot display the same activity level as in nature. For this reason, it is thought that some vegetables might better suit the dietary requirements of frugivores than commercial fruits. Some vegetables are as rich in vitamins as commercial fruits while having lower sugar levels and higher fibre contents. Therefore, if we want to better mimic the nutrient composition of wild fruits, we need to (partially) replace commercial fruits with vegetables. In support of this, we’ve established an overview of the nutritional compositions of several fruits and vegetables in order to compare them. With this data it is possible to better assess and evaluate the diets that are being fed to zoo animals. Next to this, it should encourage to critically think about the acceptance of diet components and potentially remove, add or replace them. Most macronutrients are shown, as well as the minerals iron, phosphorus and calcium. This is because some animals are prone to an iron overdosage and an unbalanced calcium/phosphorus ratio. Please be aware that both the sugar levels and starch contents are grouped under ‘available carbohydrates’ as available literature did not allow us to properly split these groups. As can be seen from the graphs, generally vegetables better mimic the nutritional values (on dry matter basis) of wild fruits compared to commercial fruits. Although not perfectly resembling wild fruits, they are a more suitable alternative. However, it should be kept in mind that there are also differences between vegetables. Generally, fiber levels of both commercial fruits and vegetables are relatively low compared to wild fruits, however, this can be supplemented in the diet with other fiber sources (browse or roughages). On the other hand, the available carbohydrate fraction tends to be higher in commercial fruits, which is (partially) the result of higher sugar levels. The table also shows that generally vegetables have a better calcium/phosphorus ratio compared to commercial fruits. Lastly, it should be noted that vegetables do contain higher iron levels. Therefore, for iron sensitive species this should be adjusted to the maintenance levels of the animal in order to avoid iron-related diseases. Also fruits with high levels of vitamin C should be avoided with iron-rich vegetables as it enhances the absorption and increases health risks. To conclude, it should be mentioned that the implementation of these changes in the diet are based on theory. In practice, animals might not always immediately tolerate dietary changes from fruits to vegetables. Regarding the used data, it can be seen that there was only few (usable and reliable) data available on the nutritional values of wild fruits. This was primarily due to the differences between methods of proximal analysis between studies, which resulted in unreliable comparisons. For this reason, we decided to only use the nutritional values for some wild fruits mentioned in Souci et al. (2008). In nature, other wild fruits may be consumed with different nutritional values. Source : Souci, S. W., Fachmann, W. & Kraut, H. (2008). Food Composition and Nutrition Tables, 7th revised and completed edition. MedPharm.
