Retention of solute and particle markers in the digestive tract of chinchillas (Chinchilla laniger )

Gastrointestinal parasites of Wolffsohn's viscacha (Chinchillidae: Lagidium wolffsohni), an endemic rodent species from the wild Patagonia

Parasites are ubiquitous in wildlife populations and have a profound impact on population dynamics. Interest in parasites of wildlife has increased significantly in recent years, particularly in those with relevant conservation status. Patagonia is one of the wildest and remote areas of the world. The Wolffsohn's viscacha lives in a small mountainous area of Patagonia. Until now, little is known about the biology and ecology of this species. The aim of this research was to study the gastrointestinal parasite diversity in this rodent from a coprological survey. A total of 125 fecal samples from 25 colonies were examined. Each sample was rehydrated, homogenized, and analyzed using three parasitological techniques: spontaneous sedimentation, Mini-FLOTAC, and centrifugation-flotation in sucrose-saturated solution, followed by examination under optical microscopy. The samples, eggs, and oocysts of parasites were described, measured, and photographed. All colonies were positive for at least one parasite species. A total of 10 parasitic species were identified: Viscachataenia sp., possibly V. quadrata, Monoecocestus sp., an unidentified anoplocephalid, Heteroxynema sp., possibly H. (Cavioxyura) viscaciae, Helminthoxys sp., possibly H. effilatus, an unidentified strongylid-type egg, Trichuris sp., two morphologies of unidentified coccidians and Eimeria sp. This is the first exhaustive study of gastrointestinal parasites in L. wolffsohni and a large number of eggs and oocysts of parasites were found. Our results highlight the use of noninvasive techniques for the study of parasites of wildlife hosts; as in the case of this rodent with a remote habitat, which makes sampling difficult. The results of our study provide baseline information on gastrointestinal parasite infections in this species.

Diagnosis and surgical treatment of colonic obstructive foreign bodies in chinchillas (Chinchilla lanigera): a case series (2017-2020)

We describe a case series of colonic foreign bodies in seven chinchillas. These animals had all shown complete lack of fecal output. Ultrasonography was performed in each case, revealing a hyperechoic foreign body with strong acoustic shadowing in the bowel in 6 of the 7 cases (86%). Foreign bodies were removed under exploratory laparotomy in all cases, with a perioperative survival rate of 71% (5/7). The foreign bodies were extracted from the distal ansa of the ascending colon (n=3), descending colon (n=3), or intermediate part of the ascending colon (n=1). This case series suggests chinchillas are affected by colonic obstructive foreign bodies and surgical intervention may be necessary to pursue better prognosis in cases where medical therapies prove ineffective.

Gut Microbial Community and Host Thermoregulation in Small Mammals

The endotherms, particularly the small mammals living in the polar region and temperate zone, are faced with extreme challenges for maintaining stable core body temperatures in harsh cold winter. The non-hibernating small mammals increase metabolic rate including obligatory thermogenesis (basal/resting metabolic rate, BMR/RMR) and regulatory thermogenesis (mainly nonshivering thermogenesis, NST, in brown adipose tissue and skeletal muscle) to maintain thermal homeostasis in cold conditions. A substantial amount of evidence indicates that the symbiotic gut microbiota are sensitive to air temperature, and play an important function in cold-induced thermoregulation, via bacterial metabolites and byproducts such as short-chain fatty acids and secondary bile acids. Cold signal is sensed by specific thermosensitive transient receptor potential channels (thermo-TRPs), and then norepinephrine (NE) is released from sympathetic nervous system (SNS) and thyroid hormones also increase to induce NST. Meanwhile, these neurotransmitters and hormones can regulate the diversity and compositions of the gut microbiota. Therefore, cold-induced NST is controlled by both Thermo-TRPs—SNS—gut microbiota axis and thyroid—gut microbiota axis. Besides physiological thermoregulation, small mammals also rely on behavioral regulation, such as huddling and coprophagy, to maintain energy and thermal homeostasis, and the gut microbial community is involved in these processes. The present review summarized the recent progress in the gut microbiota and host physiological and behavioral thermoregulation in small mammals for better understanding the evolution and adaption of holobionts (host and symbiotic microorganism). The coevolution of host-microorganism symbionts promotes individual survival, population maintenance, and species coexistence in the ecosystems with complicated, variable environments.

Companion animals as a potential source of Giardia intestinalis infection in humans in the Czech Republic - A pilot study

Giardia intestinalis is a common enteric single-celled parasite infecting both humans and animals. Its eight morphologically identical but genetically distinct groups called assemblages differ from each other in host range. While assemblages A and B infect a wide range of hosts, including humans, the other assemblages (C to H) limit their host preferences to particular animal groups only. In companion animals as Giardia hosts, genotyping data have previously shown various results depending on pet species, location, environmental or breeding conditions, and the study design. To strengthen available epidemiological data from developed countries and to evaluate the role of pets in Giardia zoonotic transmission, we investigated Giardia-positive stool samples of three pet species (54 dogs, 18 cats, and 18 chinchillas) by a sequence-based analysis of three Giardia genes (β-giardin, glutamate dehydrogenase and triose phosphate isomerase). In dog samples, we confirmed assemblage C (21/54), assemblage D (32/54), and one case of a mixed infection C + D (1/54). In cats, we found assemblage F (16/18) and assemblage A, specifically sub-assemblage AI (2/18). All Giardia samples from chinchillas were characterised as assemblage B, specifically sub-assemblage BIV (18/18). These results indicate that in the Czech Republic, pet dogs may not represent a source of Giardia infection for humans because of the presence of only canid-specific genotypes C and D. In contrast, other pets, namely, chinchillas and, to a lesser extent, cats, may pose a potential risk of Giardia transmission to owners or breeders because they can host zoonotic Giardia genotypes.

The effect of fish and mealworm larvae meals as alternative dietary protein sources on nutrient digestibility and gastrointestinal function in Chinchilla lanigera

Chinchillas are herbivores, but wild chinchillas may occasionally consume animal-based foods. The aim of this study was to determine the effect of fish meal (FM) and mealworm meal (MWM) included in complete pelleted diets on nutrient digestibility and gastrointestinal function in chinchillas. The experiment was performed on 24 male, divided into three groups, n=8. Control group (C) was fed a diet containing 10% soybean meal (SBM). In the experimental group FM, chinchillas received a diet containing 3% fish meal, and the diet administered to the experimental group MWM was supplemented with 4% dried mealworm larvae meal. The nutrient digestibility of diets was determined. At the end of the experiment animals were euthanized and their digestive tracts were removed to analyze gut activity. FM group animals were characterized by lower crude fat digestibility, whereas both alternative protein sources improved the digestibility of acid detergent fiber (ADF). A considerable increase in the activity of cecal intracellular and extracellular bacterial enzymes (in particular β-glucosidase, β-galactosidase and β-xylosidase) was noted in the FM group, which however did not increase the concentrations of short-chain fatty acids (SCFA). The inclusion of MWM in chinchilla diets shifted the bacterial fermentation site from the cecum (lowest SCFA pool) to the colon (highest SCFA pool), thus enabling to derive additional energy from less digestible dietary components. In conclusion, chinchilla diets can be supplemented with small amounts of animal protein such as fish meal and dried mealworm larvae meal.

Digestive anatomy, physiology, resting metabolism and methane production of captive maras (Dolichotis patagonum)

The digestive physiology of maras (Dolichotis patagonum) has not been investigated in detail. Maras have a particular limb anatomy facilitating a unique cursoriality among rodents. This may also have led to additional adaptations such as a reduced volume of the gastrointestinal tract. We performed macroanatomical measurements of, and determined mean particle size along, the digestive tract of 10 semi-free-ranging animals (7.04 ± 1.05 kg). Additionally, we measured CH₄ emission in five captive animals (7.67 ± 0.98 kg) fed a diet of pelleted lucerne, and measured food intake, digestibility, and digesta mean retention time (MRT) of a solute and three particle markers (fed at <2, 10 and 20 mm particle size). The digestive tract contents represented 11.1 ± 1.4% of body mass, similar to other mammals and rodents, and there was slight indication of selective small particle retention in the caecum. Secondary peaks in marker elimination patterns suggested the possibility of caecotrophy. The MRTs were 15.4 h for the solute and 13.6 h, 13.3 h and 13.3 h for the three particle markers, respectively. At a dry matter intake of 61 ± 12 g kg body mass^-0.75 d^-1, the maras digested organic matter and neutral detergent fibre to 48 ± 8% and 34 ± 10%, respectively, which is in the lower range of results from horses fed on a diet with a similar fibre content. The respiratory quotient (CO₂/O₂) was 0.93 ± 0.03, the resting metabolic rate 346 ± 35 kJ kg body mass^-0.75 d^-1, and CH₄ emissions averaged at 3.85 ± 0.47 L d^-1 and 14.5 ± 5.2 L per kg dry matter intake; this at a CH₄/CO₂ ratio of 0.042 ± 0.004. Thus, the methane yield was of a magnitude expected for a hypothetical ruminant of this body mass. The results are consistent with the general understanding of hystricomorph rodent digestive physiology, including caecotrophy, but do not indicate a reduction of digestive capacity to support cursoriality. These results, and those obtained from other hystricomorph rodents, suggest that CH₄ production may be more prominent in rodents than previously thought.

Digestive physiology of captive capybara (Hydrochoerus hydrochaeris)

The capybara (Hydrochoerus hydrochaeris), the largest living rodent, probably has a "mucus-trap" colonic separation mechanism. To test this hypothesis, we measured the mean retention time of a solute marker (MRT_Solute ), 2 mm (MRT_2 mm ), 10 mm (MRT_10 mm ), and 20 mm (MRT_20 mm ) particle markers and nutrient digestibility in adult captive capybaras (27-52 kg body mass (BM), 2-11 yr). In addition, total gut fill and the selectivity factor (MRT_Solute /MRT_2 mm ) were calculated, and mean faecal particle size and metabolic fecal nitrogen of captive capybaras were compared to those of free-ranging specimens. Finally, we also measured methane production in one animal. The MRT_2 mm (29.2 ± 8.2 hr) was different (p < 0.01) from MRT_Solute (37.0 ± 13.1 hr), MRT_10 mm (36.5 ± 8.2 hr), and MRT_20 mm (35.1 ± 9.6 hr). The selectivity factor (1.26 ± 0.30) was in the range considered typical for a "mucus-trap" colonic separation mechanism. The estimated total gut fill was 1.50 ± 0.37% and 1.73 ± 0.25% of BM calculated from the results of the 2-mm and 10-mm particle markers, respectively. The CH₄ emission was 13.7 L/day. Captive capybaras had greater mean fecal particle size (0.44 ± 0.06 vs. 0.29 ± 0.05 mm, p < 0.001) and metabolic fecal nitrogen (65.5 ± 3.91 vs. 46.8 ± 10.5% of fecal nitrogen, p < 0.001) than free-ranging capybaras. Organic matter digestibility decreased less steeply with increasing dietary crude fiber content in capybaras as compared to published data from rabbits or guinea pigs. Accordingly, the digestive physiology of the capybara is characterized by a comparatively high fiber digestibility, with a "mucus-trap" colonic separation mechanism, allowing capybaras to thrive on forage-only diets.

Determination of the Genetic Component of Fur-Chewing in Chinchillas (Chinchilla lanigera) and Its Economic Impact

Simple Summary

Many chinchillas kept in captivity develop fur-chewing. This behavior does not only affect fur price, but most importantly it can be the result of an animal welfare problem. The causes of this behavior are not well understood and a genetic component could exist. This is why the aim of this study was to determine the genetic component and the effect of this behavior on fur price. The data from a commercial fur-farm was used, it included information on 10,196 chinchillas recorded between 1990 and 2011. The heritability of the behavior and its effect on fur price were determined. The results show a significant genetic variation in fur-chewing with an estimated heritability of 0.16. At the same time, the behavior had an important negative effect on fur price. The selection and management practices used in fur-farming should be improved in order to decrease the incidence of this behavior.

Abstract

Fur-chewing is a common behavioral disorder developed by chinchillas kept in confinement that can indicate a past or present welfare problem. It also has a negative productive impact associated. The aim of this study was to determine the genetic component of fur-chewing, and the effect of this undesired behavior on fur price in a commercial fur-farming system of chinchillas (Chinchilla lanigera). The data for the analysis was derived from a commercial population of 10,196 chinchillas, recorded between the years 1990 and 2011. For determining differences in fur price according to presence of fur-chewing behavior, analysis of variance (ANOVA) was used, considering 3007 animals. For estimation of variance components of fur-chewing a sire-dam threshold (probit) mixed model was used, using data of 9, 033 individuals, and then heritability on the underlying liability scale was calculated. The analysis revealed a significant negative impact on fur price from fur-chewing chinchillas (p-value < 0.05). In addition, the study showed that fur-chewing presents significant genetic variation, with an estimated heritability of 0.16. The presentation of fur-chewing should be taken into account when selecting broodstock in these systems, in order to reduce the number of affected individuals.