The objective of this research was to evaluate the amino acid composition of proteins in the dorsal muscle, femoral muscle, and the liver of female nutrias (Myocastor coypus Molina) in relation to ...age. In this study a total of 50 animals were used. The animals were split into two groups based on their age, i.e. 7 months old and 24 months old. The amino acids were separated and quantitatively determined using an automated analyser. Using a two-way analysis of variance, significant differences (P˂0.05) were determined between the tested parameters, muscle type and age. In this study, statistically significant differences were found in the dorsal muscle in the content of glycine, which was higher in young animals and in the content of aspartic acid, which was higher in older animals. In the case of the femoral muscle, significantly higher content of serine, glycine and arginine were found in the group of 7-month-old animals. In contrast, the group of 24-month-old nutria in the femoral muscle showed a higher content of alanine, valine and phenylalanine. In the liver, significantly higher contents of some amino acids were found only in the group of young, 7 months old nutrias. Higher content was observed for aspartic acid, threonine, serine, glutamic acid, proline and histidine. Additionally, nutria meat, particularly meat from the dorsal muscle, is a rich source of amino acids, especially essential amino acid, glutamic acid and aspartic acid, making it yet another quality source of protein in a balanced human diet.
Under various ecological conditions, producing a biased sex ratio may be adaptive. However, the factors that translate specific ecological conditions into internal processes remain an enigma. A ...potential mediator is maternal testosterone, which may reflect physical, reproductive, and social conditions. The nutria (Myocastor coypus) is a polygynous rodent, invasive in many parts of the world, which shows fluctuating sex ratios. Using necropsies of 82 pregnant culled nutrias, we found that in early pregnancy, offspring sex ratios are more male-biased than in later pregnancy. Since sex ratios decrease with pregnancy age, male fetuses in our study population may be terminated. In 68% of the litters, the heaviest fetus was a male, suggesting that males are the "expensive" sex. We also found that while maternal weight was not associated with testosterone, heavier females and those with lower testosterone had male-biased sex ratios. Litters of high testosterone females had female-biased sex ratios. To the best of our knowledge, this study is the first to show a negative association between maternal testosterone and male-biased sex ratios. Testosterone, through its role in reproduction, might be mediating maternal internal and external conditions by adjusting intra-uterine sex ratio.
Nutria (or coypu, Myocastor coypus), is a semi-aquatic rodent that is native to South America and has been introduced almost all over the world since the end of the 19th century. In Europe, this ...rodent is considered an invasive species. In this report, we analyzed nutria fecal samples in a small coastal wetland of Central Italy, using different techniques (fresh smear, direct immunofluorescence, Baermann technique, flotation, ethyl acetate sedimentation) to obtain an arrangement of eukaryote endoparasites (Protozoa and Helminths) and compare them with data available in the literature for both Italy and worldwide. We recorded five taxa, with a dominant occurrence (>70%) of nematodes of the genus Strongyloides. Moreover, we reported for the first time in nutria a bronchopulmonary strongyle nematode (Muellerius vel. Angiostrongylus) and, for the first time in Italy, protozoans of the genus Cryptosporidium. Since nutria co-occurs with humans and domestic animals in the study area, we highlighted possible sanitary and management implications.
Nutria (
Myocastor coypus
) were introduced into South Korea in 1985 for fur farming and meat production. However, failures of nutria farm management in the late 1990s resulted in the accidental ...and/or intentional release of nutria into the wild, and they have spread and become serious pests. The successful management of invasive species like nutria somewhat depends on the comprehensive knowledge of distribution patterns. Therefore, this study aimed to identify the distribution, spread, and habitat preferences of nutria invading the lower Nakdong River in South Korea to facilitate current control and eradication endeavours. Nutria populations were recorded in 45 of 236 sites investigated. The distribution patterns revealed that the spread of nutria from farming sites has mainly proceeded along rivers via tributaries. Important factors associated with the establishment of new populations were food availability, levees with suitable burrow materials, and slow water flow. The winter climate was also important, and the total number of days below −4 °C significantly affected nutria occurrence. To date, efforts to control or locally eradicate nutria populations have had little success due to insufficient budgets and the lack of coordinated management activities between local governments. To improve the efficiency of nutria eradication programmes, local governments must establish an integrated and coordinated strategy that is overseen by a single, national agency. To ensure the success of the programmes, this agency should make the best use of ecological information about nutria distribution, and utilize optimal control techniques and timing.
Wildlife value orientations (WVOs) can predict consensus or controversy over wildlife-related issues and are therefore important for their successful management. We carried out on-site face-to-face ...interviews with Greek people (n = 2392) to study two basic WVOs, i.e., domination (prioritize human well-being over wildlife) and mutualism (wildlife has rights just as humans). Our sample was more mutualism-oriented than domination-oriented; however, domination was a better predictor of management acceptability than mutualism. WVOs were better predictors of the acceptability of lethal strategies (shooting, destruction at breeding sites, 11–36% of variance explained) relative to taking no action (9–18%) and non-lethal strategies (e.g., compensation, fencing, trapping, and relocating, 0–13%). In addition, the predictive ability of WVOs, mostly for accepting lethal strategies, increased with the increasing severity of the conflict (crop damage, attacking domestic animals, 11–29%; disease transmission, 17–36%) and depending on species conservation status and provenance (endangered native brown bear (Ursus arctos), 11–20%; common native red fox (Vulpes vulpes), 12–31%; common exotic coypu (Myocastor coypus), 17–36%). Managers should consider these findings for developing education and outreach programs, especially when they intend to raise support for lethal strategies. In doing so, they would be able to subsequently implement effective wildlife management plans.
Abstract
Although plasticity of growth rates is mainly associated with ectotherm species, it does occur in endotherms as well, but has not been documented systematically for many species. We compared ...the effect of 2 common types of feeding systems, differing in energetic value, on body size and gastrointestinal tract morphology in nutrias (Myocastor coypus). A total of 30 extensively (E) fed and 20 intensively (I) fed animals were used in the study. We noted significant effects of age, sex, and feeding regime on body weight and length, with 1-yr-old females attaining 3.7 ± 0.4 kg and 33.4 ± 1.5 cm on E and 4.9 ± 0.3 kg and 36.1 ± 2.3 cm on I. A significant treatment-sex interaction indicated that treatment had a greater effect on the length growth in males (1-yr-old males attaining 4.0 ± 0.2 kg and 34.7 ± 1.2 cm on E and 5.4 ± 0.4 kg and 41.0 ± 1.4 cm on I). The differences matched individual literature reports of free-ranging or intensively fed nutrias. The majority of gastrointestinal tract measurement results were only related to body weight, without additional effect of the diet regime, except for a higher small intestinal tissue weight on I (79 ± 14 g vs. 61 ± 7 g on E). In contrast, the wet content weight of the stomach, caecum, and the total gastrotinestinal tract was higher on E (196 ± 34 g vs. 164 ± 51 g on I). Overall, we observed strong influence of dietary regime on body development but not on digestive anatomy, indicating a distinct phenotypic flexibility in growth rates in nutrias.
The capybara (Hydrochoerus hydrochaeris) is a selective herbivore that may show a preference for certain plant species. Such a preference is likely to be explained by the nutritional benefits ...hypothesis, stating that the nutritional value of species selected by capybaras is higher than that of avoided ones. Therefore, the objectives of this work are to evaluate the nutritional value of the plant species eaten by capybaras in the Lower Delta of the Paranaa River, and to test the nutritional benefits hypothesis by analyzing forage quality. Samples of consumed plant species were collected from habitats located in the study area. We also collected plant species that are very abundant in the field but absent in the capybara's diet, some of which are consumed by other native herbivores such as coypus (Myocastor coypus). Their nutritional quality was analyzed by estimating the following variables: water content, ash percentage, percentage of organic matter, acid detergent fiber, nitrogen percentage, crude protein, and caloric energy. The protein to fiber ratio was calculated and the water content was determined. The species consumed and not consumed by capybaras had a similar nutritional composition for all the variables analyzed (P < 0.05). A similar result was observed when comparing within consumed species, except for the caloric energy content, which was significantly higher in species consumed in greater proportion than availability (P < 0.05). Water content was at its minimum in species consumed in greater proportion than availability, and at its maximum in unconsumed species. No significant differences were found between consumed Poaceae and the rest of the consumed plant species for any of the analyzed variables. Diet selection by capybaras in the studied area may only be partially related to nutritional quality, and there would be other factors involved in foraging, such as physiological mechanisms of the animal or chemical and structural characteristics of food.
A novel polyomavirus (PyVs) comprising 5,422 bp was identified by high-throughput sequencing (HTS) in pooled organs of nutria (
Myocastor coypus
). The new genome displays the archetypal organization ...of PyVs, which includes open reading frames for the regulatory proteins small T antigen (sTAg) and large T antigen (LTAg), as well as for the capsid proteins VP1, VP2 and VP3. Based on the International Committee on Taxonomy of Viruses (ICTV)
Polyomaviridae
Study Group criteria, this genome comprises a new PyVs species for the
Alphapolyomavirus
genus and is putatively named “
Myocastor coypus Polyomavirus
1” . The complete genome sequence of this Myocastor coypus Polyomavirus 1 (McPyV1) isolate is publically available under the GenBank accession no. MH182627.
Nutria (
) are semi-aquatic rodents that were introduced in South Korea for commercial farming but significantly damaged aquatic ecosystems. Understanding nutria ecological behavior is essential for ...developing effective control and eradication strategies to mitigate their impacts. Thus, this study aimed to investigate the home range and activity patterns of 24 nutria (12 males and 12 females) in the Macdo wetland in South Korea from 2015-2016 through radio tracking. The average minimum convex polygon home range of the nutria was 0.29 ± 0.55 km
, with a 95% kernel density estimation (KDE) home range of 0.43 ± 0.85 km
and a 50% KDE home range of 0.05 ± 1.1 km
. The home range of males was larger than that of females; however, the winter home range of females was as large as that of males. The home range also varied seasonally, with the smallest observed in winter. The nutria showed crepuscular and nocturnal activity patterns throughout the year, with no significant difference between sexes. The activities in spring, summer, and autumn showed no significant differences, but the activity in winter was significantly different from that in the other seasons. This study may serve as a basis for developing appropriately timed and scaled management strategies to mitigate the impacts of nutria on ecosystems. In conclusion, several environmental and biological factors contribute to the behavior of nutria in South Korea.
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