Body size and gastrointestinal morphology of nutria (Myocastor coypus) reared on an extensive or intensive feeding regime

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 two 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 one-year-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 (one-year-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.

Weigh and see—Body mass recordings versus body condition scoring in European zoo elephants (Loxodonta africana and Elephas maximus)

“…The continuous provision of an unnaturally energy‐rich diet and reduced physical activity under zoo conditions can explain this difference (Hatt & Clauss, ). The positive correlation between diet and growth rate is well‐known in farm animals (Blanco et al, ; Borton et al, ; Pla, ), has been detected in reptiles (Ritz et al, ), as well as in several primate species (Leigh, ) and nutria (Głogowski et al, ) and might exist in further wildlife species. Moreover, dependence of height growth on caloric intake has been demonstrated in humans (Berkey, Gardner, Frazier, & Colditz, ; Fomon et al, ).…”

“…We consider these natural conditions appropriate for comparison because they may most likely represent the situation in which elephant species evolved their peculiar digestive physiology. Under the assumption of a constant energy‐rich diet under zoo conditions (Hatt & Clauss, ), we expect increased growth rates in the more intensively managed zoo population as shown in reptiles, primates and rodents (Glogowski et al, ; Leigh, ; Ritz et al, ).…”

Adaptation of nutria meat to industrial technologies of the meat industry

“…Muscle and adipose tissue, their quantitative ratio in carcasses, qualitative composition and processing conditions have the greatest technological importance in sausage production. The ratio of muscle and connective, fat, bone and cartilage tissues in the carcass of the nutria is at the level of beef and is 69-72%:13-14%:15-17%, respectively (Kozlova, Sidorova and Cheremenina, 2017;Głogowski, Pérez and Clauss, 2018;Nalyvaiko et al, 2019).…”