Body Of Small Animals Research Articles

Prey body size generates bias for human and avian agents: Cautions for interpreting small game assemblages

Identifying the accumulating agent(s) of small animal assemblages at archaeological sites is challenging given the range of behaviors, skeletal plans, and body sizes of prey species as well as the range of potential predators. Although mammalian carnivores, raptors, and humans are considered typical predators of small game, there are many contexts—especially in island ecosystems—where humans and raptors are the primary agents for small animal assemblages in the absence of mammalian carnivores. Moreover, smaller animals tend to range in body sizes in these geographically restricted ecosystems. This study aims to broadly explore: 1) how small animal body size affects the taphonomic signature(s) of human and avian predation; and 2) how human and avian-generated small game assemblages compare with one another. To investigate these questions, this study compared the resulting taphonomic patterns of small animal predation by raptors and humans using data collected during a controlled-feeding experiment and an observational study, respectively. In the controlled-feeding experiment, deceased laboratory rats (Rattus norvegicus domestica) (50–500 g) were fed to two Milky Eagle Owls (Ketupa lacteus), one King Vulture (Sarcoramphus papa), and two Lappet-Faced Vultures (Torgos tracheliotos). In the observational study, we explored how humans processed various species of small prey ranging in body mass (80–5000 g) by analyzing anthropogenic modifications (i.e., cutmarks, tooth marks, burning). The resulting small animal assemblages were analyzed post-consumption for skeletal element representation, fragmentation and breakage patterns, and bone surface modifications. Results show that small prey body size significantly affects pre-depositional patterning in terms of skeletal element survival, butchering intensities, and cutmark frequencies. Furthermore, our experimentally generated assemblages show that breakage, fragmentation, and element relative abundance patterns can be used to distinguish between human and avian-accumulated assemblages in the archaeological record.

Bulk Electroacupuncture Operation for Mice or Young Rats.

Electroacupuncture (EA) is widely used to treat various health conditions. However, the underlying mechanism of EA treatment remains unclear, hindering its promotion. The mechanistic study requires mouse or rat models to address this issue. However, these animals are not obedient to the experimental process, which is time-consuming. To solve these problems, we designed a 3D-printed small animal body bulk fixator to improve the efficiency of EA's animal experiments. This video shows in detail how to use the fixator to perform bulk EA on mice or young rats. For the selection of acupoints, the anterior oblique line of vertex temporal (MS6 head) and Tianshu point (ST25 belly) were chosen to verify the effect of the fixation device with prone positioning and supine positioning. Using the 3D-printed small animal holder allows multiple rodents to be immobilized and treated simultaneously, reducing the time and resources required for the experiment. This technique could be applied to other animal models by 3D printing different sizes and could potentially be used for various fixing conditions. The device is beneficial for the promotion of experimental scientific research in EA.

Validation of a novel testing machine for the investigation of the biomechanical properties of lumbar vertebrae in an osteoporotic rat model

BackgroundFor the investigation of the biomechanical properties of bone, various testing devices have been described. However, only a limited number have been developed to test the vertebral body of small animals. The aim of this study was to develop and validate a new bone testing device, which investigates the different biomechanical properties in small-animal vertebrae as a whole, three-dimensional unit, respecting its anatomical structure.MethodsThirty-five twelve-week-old female Sprague Dawley rats were utilized. Group 1 was composed of 17 rats with a normal bone metabolism without osteoporosis, while Group 2 consisted of 18 rats with manifest osteoporosis, 8 weeks after ovariectomy. The 5th lumbar vertebra of each animal was tested using the new bone testing device. This device has the ability to be adjusted to the slanted nature of each individual vertebral body and fix the vertebra in a natural position to allow for a non-dislocating axial force application. The device is designed to respect the anatomical three-dimensional shape of the vertebral body, thus avoiding the application of non-anatomic, non-physiological forces and thus preventing a distortion of the biomechanical testing results. The parameters investigated were stiffness, yield load, maximum load and failure load, and the results were compared to current literature values.ResultsThe conduction of the biomechanical bone testing of the vertebral bodies with the new device was conductible without any instances of dislocation of the vertebrae or machine malfunctions. Significant differences were found for stiffness, maximum load and failure load between groups, with a lower value in the osteoporotic rats in each parameter tested. The yield load was also lower in the osteoporotic group, however not significantly. The values achieved correlate with those in current literature.ConclusionsThis study demonstrates that the newly developed testing machine is easy to handle and produces valid data sets for testing biomechanical bone parameters of whole vertebral bodies in an established small animal model. Therefore, it can be utilized, also as reference data, to test different structural properties and changes in vertebral bone, for example, in different metabolic settings or under the influence of different pharmaceutical entities in further studies.

Ultrasound-Guided Breath-Compensation in Single-Element Photoacoustic Imaging for Three-Dimensional Whole-Body Images of Mice

Photoacoustic imaging can be used to extract functional information at the molecular level for imaging the whole body of small animals in vivo. However, the use of a mechanical scanner to image the whole body involves acquiring the data for a period of time which can lead to breathing-related artifacts. Thus, the acquired three-dimensional data cannot be analyzed and visualized using two-dimensional projection rendering techniques unless the respiratory distortions are minimized. In this study, an ultrasound-guided breath-compensation method for the three-dimensional data of photoacoustic macroscopy to facilitate visualization and analysis in the depth direction is presented. Photoacoustic and ultrasound data of the whole body of mice were acquired in vivo, then the distorted skin layers were compensated in ultrasound data. The extracted distortion parameters were then applied to the corresponding photoacoustic data to compensate for the motion. The compensation method was successfully applied to visualize three-dimensional hemoglobin oxygen saturation in the whole body of mice in vivo by using multispectral photoacoustic data. The resulting three-dimensional images show that the developed methodology can be used in various biomedical studies, including monitoring drug delivery, imaging of tumors, and analysis of vasculature networks.

Toward whole-body quantitative photoacoustic tomography of small-animals with multi-angle light-sheet illuminations.

Several attempts to achieve the quantitative photoacoustic tomography (q-PAT) have been investigated using point sources or a single-angle wide-field illumination. However, these schemes normally suffer from low signal-to-noise ratio (SNR) or poor quantification in imaging applications on large-size domains, due to the limitation of ANSI-safety incidence and incompleteness in the data acquisition. We herein present a q-PAT implementation that uses multi-angle light-sheet illuminations and calibrated recovering-and-averaging iterations. The scheme can obtain more complete information on the intrinsic absorption from the multi-angle illumination mode, and collect SNR-boosted photoacoustic signals in the selected planes from the wide-field light-sheet excitation. Therefore, the sliced absorption maps over whole body of small-animals can be recovered in a measurement-flexible, noise-robust and computation-economic way. The proposed approach is validated by phantom, ex vivo and in vivo experiments, exhibiting promising performances in image fidelity and quantitative accuracy for practical applications.

Trans-illumination fluorescence imaging of deep-seated tumors in small animals

AbstractBackground:Fluorescence diffuse tomography (FDT) is the most accurate technique for the imaging of labeled tumors in the small animal body. However, the procedure for reconstruction of the spatial distribution of the fluorophore requires a high signal-to-noise ratio due to the ill-condition of the inverse problem. Therefore, the FDT technique is ineffective for imaging tumors of small size or with dim fluorophores because of the low intensity of their fluorescence compared with the high level of tissue autofluorescence. In these cases, the size and position of a marked tumor in the animal body can be estimated from two-dimensional fluorescence images obtained using trans- or epi-illumination techniques.Material and methods:A versatile system for small animal fluorescence imaging which combines planar epi- and trans-illumination geometries of the light source and of the fluorescence receiver was created and tested. For epi-illumination imaging, light-emitting diode sources were used to provide homogeneous and stable illumination of the experimental animal, in combination with a cooled CCD camera which covers the entire illuminated area. For trans-illumination imaging, mechanical raster-scanning devices modulated at a low frequency were used for the laser source, together with a cooled photomultiplier tube, which provided outstanding sensitivity.Results:Monitoring the orthotopic tumor growth in animal bodies has demonstrated the efficacy of trans-illumination imaging in comparison with the epi-illumination technique. The results obtained also showed that the effective use of the trans-illumination technique requires Born normalization of the fluorescence signal and the exclusion of lateral illumination by surrounding the animal with additional light absorption material using light-absorption pads on both sides of the body.

Special issue on biomedical optics

Biomedical optics is an interdisciplinary field of combining principles of optics with a variety of technologies in biology, biophysics, biochemistry, medicine, computer science and bio-related engineering. This field has been gaining a great interest due to unique characteristics of light, for example, high spatial resolution, three-dimensional and real-time detection, noninvasive or minimally invasive procedure and simple manipulation. Such light-based research encompasses a wide range of basic study, inspection, diagnostics and therapy of biological cells and tissues. In order to keep pace with rapid advancement and to introduce current research trends, we select biomedical optics as a theme of this Special Issue of Biomedical Engineering Letters. This Special Issue includes five review articles and one original research paper covering various state-of-the-art technologies. The first paper entitled “The potential of naturally occurring lasing for biological and chemical sensors” by Choi and Kim introduces alternative biosensing methods of taking advantage of naturally occurring lasers, also known as random lasers [1]. In random lasers, resonances are selfformed due to multiple scattering, leading to light amplification and coherent light generation in the presence of amplifying media. In this case, lasing emission can be unprecedentedly sensitive to subtle nanoscale perturbations. The authors address that random lasers can be an alternative yet superior physical mechanism for biosensors, because the random laser biosensing platform is simple and the detection strategy is straightforward. The second paper entitled “Acoustic resolution photoacoustic microscopy” by Park and colleagues reviews the principle and system implementation of acoustic-resolution photoacoustic microscopy (AR-PAM) [2]. Note that, by combining information provided by light and acoustic properties, it is possible to realize high sensitivity and specificity, strong contrast of biological tissues, and relatively deep penetration beyond the depth limitation of traditional optical imaging. The authors also present several applications of AR-PAM to image biological tissues such as sentinel lymph nodes, lymphatic systems, bladders, gastrointestinal tracts, and whole body of small animals. Owing to its outstanding imaging capability, AR-PAM is anticipated to be applied for a variety of biomedical imaging researches. The third paper entitled “Recent functional near infrared spectroscopy based brain computer interface systems: Developments, applications and challenges” is described by Phillips V and Kim [3]. Portable and convenient functional near infrared spectroscopy (fNIRS) can provide an enormous Kyung Min Byun ( ) Kyung Hee University, Yongin, Republic of Korea Tel : +82-31-201-3842 / Fax : +82-31-202-1723 E-mail : kmbyun@khu.ac.kr

Resolving fluorophores by unmixing multispectral fluorescence tomography with independent component analysis

It is a challenging problem to resolve and identify drug (or non-specific fluorophore) distribution throughout the whole body of small animals in vivo. In this article, an algorithm of unmixing multispectral fluorescence tomography (MFT) images based on independent component analysis (ICA) is proposed to solve this problem. ICA is used to unmix the data matrix assembled by the reconstruction results from MFT. Then the independent components (ICs) that represent spatial structures and the corresponding spectrum courses (SCs) which are associated with spectral variations can be obtained. By combining the ICs with SCs, the recovered MFT images can be generated and fluorophore concentration can be calculated. Simulation studies, phantom experiments and animal experiments with different concentration contrasts and spectrum combinations are performed to test the performance of the proposed algorithm. Results demonstrate that the proposed algorithm can not only provide the spatial information of fluorophores, but also recover the actual reconstruction of MFT images.

Small-animal whole-body photoacoustic tomography: a review.

With the wide use of small animals for biomedical studies, in vivo small-animal whole-body imaging plays an increasingly important role. Photoacoustic tomography (PAT) is an emerging whole-body imaging modality that shows great potential for preclinical research. As a hybrid technique, PAT is based on the acoustic detection of optical absorption from either endogenous tissue chromophores, such as oxyhemoglobin and deoxyhemoglobin, or exogenous contrast agents. Because ultrasound scatters much less than light in tissue, PAT generates high-resolution images in both the optical ballistic and diffusive regimes. Using near-infrared light, which has relatively low blood absorption, PAT can image through the whole body of small animals with acoustically defined spatial resolution. Anatomical and vascular structures are imaged with endogenous hemoglobin contrast, while functional and molecular images are enabled by the wide choice of exogenous optical contrasts. This paper reviews the rapidly growing field of small-animal whole-body PAT and highlights studies done in the past decade.

Monte Carlo simulations of GeoPET experiments: 3D images of tracer distributions (18F, 124I and 58Co) in Opalinus clay, anhydrite and quartz

Understanding conservative fluid flow and reactive tracer transport in soils and rock formations requires quantitative transport visualization methods in 3D+t. After a decade of research and development we established the GeoPET as a non-destructive method with unrivalled sensitivity and selectivity, with due spatial and temporal resolution by applying Positron Emission Tomography (PET), a nuclear medicine imaging method, to dense rock material. Requirements for reaching the physical limit of image resolution of nearly 1mm are (a) a high-resolution PET-camera, like our ClearPET scanner (Raytest), and (b) appropriate correction methods for scatter and attenuation of 511keV—photons in the dense geological material. The latter are by far more significant in dense geological material than in human and small animal body tissue (water).Here we present data from Monte Carlo simulations (MCS) reflecting selected GeoPET experiments. The MCS consider all involved nuclear physical processes of the measurement with the ClearPET-system and allow us to quantify the sensitivity of the method and the scatter fractions in geological media as function of material (quartz, Opalinus clay and anhydrite compared to water), PET isotope (18F, 58Co and 124I), and geometric system parameters. The synthetic data sets obtained by MCS are the basis for detailed performance assessment studies allowing for image quality improvements. A scatter correction method is applied exemplarily by subtracting projections of simulated scattered coincidences from experimental data sets prior to image reconstruction with an iterative reconstruction process.

Magnetic particle imaging scanner with 10-kHz drive-field frequency

Magnetic particle imaging (MPI) can be used as a fast diagnostic method for obtaining three-dimensional images from inside the body of small animals by the use of functionalized magnetic nanoparticles as tracer. Here, we present our scanner setup working at 10-kHz drive-field frequency to sample a field of view of 22 × 22 × 15 mm(3) with up to 32 volume images per second. A resolution of about 1 × 2 × 1 mm(3) is achieved with iron oxide nanoparticles (Resovist). We discuss the properties of the complete system for application in imaging small animals such as mice.

TU-C-BRB-07: Comparison of Preclinical and Clinical Conformal Radiation Therapy Techniques and Protocols to Establish a Translational Pathway

Purpose: The purpose of this study was to compare the techniques and protocols used in clinical radiation therapy and recently developed preclinical image guided micro irradiation to establish a link between small animal conformal irradiation and clinical treatment protocols. This work will establish protocols that, according to treatment site, will facilitate the translation of conclusions from radiobiological experiments to clinical applications, fostering the advancement of radiotherapy.Methods: Data was gathered using our small animal image guided micro irradiation device, the microIGRT, as an example of preclinical techniques which mimic equivalent clinical treatment protocols. The microIGRT utilizes fractionated treatments, multibeam irradiations, modulated beams, image guided treatment verification, and doses to emulate clinical protocols. Consequently, it is well suited to establish parametric comparisons between clinical and preclinical techniques. In this study, we concentrated on two treatment sites, brain and lung, to define treatment conformality index, homogeneity, penumbra, PDD, and fractionated doses to establish a link to guide radiobiological experiments using clinical protocols as a gold standard. Results: Three and five beam irradiations were delivered to a small animal body and head phantom with radiochromic film to simulate lung and braintreatment. A three beam irradiation to the lung yielded a 625 um penumbra. Compare this value with a human treatment penumbra of 1 cm, and penumbra scales as the ratio between body sizes. The homogeneity of our system is similar to the 10% typically used in clinical treatment planning.Conclusions: By comparing preclinical and clinical treatment metrics, the extent of translation can be determined and improved, leading to better understanding of preclinical results and improved correlation with clinical procedures. This will lead to more clinically based preclinical experiments and improve translation efficiency between the two testing environments, thus providing new clinical treatment strategies and improved human cancer treatment.

Unmixing Dynamic Fluorescence Diffuse Optical Tomography Images With Independent Component Analysis

Dynamic fluorescence diffuse optical tomography (D-FDOT) is important for drug delivery research. However, the low spatial resolution of FDOT and the complex kinetics of drug limit the ability of D-FDOT in resolving metabolic processes of drug throughout whole body of small animals. In this paper, we propose an independent component analysis (ICA)-based method to perform D-FDOT studies. When applied to D-FDOT images, ICA not only generates a set of independent components (ICs) which can illustrate functional structures with different kinetic behaviors, but also provides a set of associated time courses (TCs) which can represent normalized time courses of drug in corresponding functional structures. Further, the drug concentration in specific functional structure at different time points can be recovered by an inverse ICA transformation. To evaluate the performance of the proposed algorithm in the study of drug kinetics at whole-body level, simulation study and phantom experiment are both performed on a full-angle FDOT imaging system with line-shaped excitation pattern. In simulation study, the nanoparticle delivery of indocynaine green (ICG) throughout whole body of a digital mouse is simulated and imaged. In phantom experiment, four tubes containing different ICG concentrations are imaged and used to imitate the uptake and excretion of ICG in organs. The results suggest that we can not only illustrate ICG distributions in different functional structures, but also recover ICG concentrations in specific functional structure at different time points, when ICA is applied to D-FDOT images.

IN VIVO ESTIMATION OF BODY FAT CONTENT OF NEW-BORN RABBITS USING THE TOBEC METHOD

An EM-SCAN SA-2 type Small Animal Body Composition Analyser (TOBEC) was used to determine the total conductivity index (E value) of 50 new-born rabbits. After the TOBEC measurements the animals were slaughtered and their bodies were homogenised by grinding twice; fat content was then determined by a chemical procedure. A weak correlation (r=-0.09) was obtained between E value and body fat percentage. Due to the high correlation between E value and body weight (r=0.90), estimated fat content was corrected for this trait [CF(%) = 11.7 - 0.1127 x (1.61 x (BW - BW) + E)], resulting in a marked improvement in the correlation (r=0.51) between predicted and measured fat content. In spite of this improvement, the medium correlation makes the TOBEC method unsuitable far the accurate prediction of body fat content of new-born rabbits, although it can be used far the identification of animals with extremely high or low fat content.

A Parallel Excitation Based Fluorescence Molecular Tomography System for Whole-Body Simultaneous Imaging of Small Animals

Challenges remain in imaging complete dynamic physiological processes in vivo through the whole small animal body using fluorescence molecular tomography (FMT). In this article, a novel non-contact full-angle FMT system that enables whole-body simultaneous imaging of small animals is presented. The whole-body simultaneous imaging ability is achieved by employing a line-shaped parallel excitation source, which can provide extended spatial sampling dataset to reconstruct multiple fluorescent targets distributed in whole animal body during one full-angle FMT imaging process. The key performances of this system were evaluated by a series of experiments. Quantitation linearity for over two orders of magnitude of fluorescence markers concentration was demonstrated, and an accessible simultaneous imaging domain of 4.0 x 1.5 cm² could be achieved utilizing the parallel excitation pattern. Moreover, the in vivo imaging feasibility and performance were validated by localizing two fluorescent targets implanted at different positions of a nude mouse. The results suggest that compared with conventional single point excitation FMT system, the proposed system can achieve a whole-body simultaneous imaging domain and impart the ability to image complete dynamic physiological processes in vivo.

Spectrally resolved bioluminescence tomography with the third-order simplified spherical harmonics approximation

Bioluminescence imaging has been extensively applied to in vivo small animal imaging. Quantitative three-dimensional bioluminescent source information obtained by using bioluminescence tomography can directly and much more accurately reflect biological changes as opposed to planar bioluminescence imaging. Preliminary simulated and experimental reconstruction results demonstrate the feasibility and promise of bioluminescence tomography. However, the use of multiple approximations, particularly the diffusion approximation theory, affects the quality of in vivo small animal-based image reconstructions. In the development of new reconstruction algorithms, high-order approximation models of the radiative transfer equation and spectrally resolved data introduce new challenges to the reconstruction algorithm and speed. In this paper, an SP3-based (the third-order simplified spherical harmonics approximation) spectrally resolved reconstruction algorithm is proposed. The simple linear relationship between the unknown source distribution and the spectrally resolved data is established in this algorithm. A parallel version of this algorithm is realized, making BLT reconstruction feasible for the whole body of small animals especially for fine spatial domain discretization. In simulation validations, the proposed algorithm shows improved reconstruction quality compared with diffusion approximation-based methods when high absorption, superficial sources and detection modes are considered. In addition, comparisons between fine and coarse mesh-based BLT reconstructions show the effects of numerical errors in reconstruction image quality. Finally, BLT reconstructions using in vivo mouse experiments further demonstrate the potential and effectiveness of the SP3-based reconstruction algorithm.

On the accuracy of protein determination in large biological samples by prompt gamma neutron activation analysis

A prompt gamma neutron activation analysis (PGNAA) facility has been developed for the determination of nitrogen and thus total protein in large volume biological samples or the whole body of small animals. In the present work, the accuracy of nitrogen determination by PGNAA in phantoms of known composition as well as in four raw ground meat samples of about 1kg mass was examined. Dumas combustion and Kjeldahl techniques were also used for the assessment of nitrogen concentration in the meat samples. No statistically significant differences were found between the concentrations assessed by the three techniques. The results of this work demonstrate the applicability of PGNAA for the assessment of total protein in biological samples of 0.25–1.5kg mass, such as a meat sample or the body of small animal even in vivo with an equivalent radiation dose of about 40mSv.

Time-dependent whole-body fluorescence tomography of probe bio-distributions in mice

We present a fast scanning fluorescence optical tomography system for imaging the kinetics of probe distributions through out the whole body of small animals. Configured in a plane parallel geometry, the system scans a source laser using a galvanometer mirror pair (tauswitch~1ms) over flexible source patterns, and detects excitation and emission light using a high frame rate low noise, 5 MHz electron multiplied charge-coupled device (EMCCD) camera. Phantom studies were used to evaluate resolution, linearity, and sensitivity. Time dependent (deltat=2.2 min.) in vivo imaging of mice was performed following injections of a fluorescing probe (indocyanine green). The capability to detect differences in probe delivery route was demonstrated by comparing an intravenous injection, versus an injection into a fat pocket (retro orbital injection). Feasibility of imaging the distribution of tumor-targeted molecular probes was demonstrated by imaging a breast tumor-specific near infrared polypeptide in MDA MB 361 tumor bearing nude mice. A tomography scan, at 24 hour post injection, revealed preferential uptake in the tumor relative to surrounding tissue.

Reproduction of rabbit does divergently selected for body fat content

Body fat content of Pannon White rabbits was determined at 10 weeks of age using an EMSCAN SA-3152 type Small Animal Body Composition Analyser (TOBEC method). Based on the fat determined content, the best and worst 16% of does and the best and worst 8% of bucks were chosen and mated with each other (a fatty doe with a fatty buck and a lean doe with a lean buck). Changes in the conception rate showed that rabbits selected for a high body fat content became pregnant at a higher rate compared to rabbits with a low body fat. In contrast to this nonfatty does showed better results in the case of litter size at birth. In the case of alive born pups also the superiority of non-fatty does was observed, but the differences between the groups were less important in this case. The reason of this may be in the changes of dead born pups. The mortality rate of pups during the suckling period (till 21 days of age) showed that the mortality of the offspring of non-fatty does was higher compared to the offspring of fatty ones. As conclusion it was established, that does selected for high body fat content have mostly higher conception rate, produce smaller litters at birth, but because of the lower mortality rate of their offspring during the suckling period they have larger and heavier litters at 21 day after parturition as compared to the non-fatty ones.

Einfluss des nach der TOBEC-Methode bestimmten Fettgehaltes bei Kaninchen auf die Wurfleistungen und die Körperzusammensetzung der Nachkommen

Abstract. Title of the paper: Effect of selection on body fat content by means of the TOBEC method on some reproductive traits of rabbit does and on the body composition of growing rabbits In this experiment body fat content of Pannon White growing rabbits was determined at 10 weeks of age using an EM-SCAN SA-3152 type Small Animal Body Composition Analyser (TOBEC method). Based on the fat content determined the best and worst 16% of the does and the best and worst 8% of the bucks were chosen and mated with each other (fatty doe with fatty buck and lean doe with lean buck). It was found that the conception rate was significantly higher and the number of inseminations needed for the second kindling significantly lower in the case of fatty rabbits. An important, but not significant difference was observed in the case of total litter size at birth, which decreased in the case of live born litter size. This reason was the significantly higher ratio of the dead born pups in the case of non-fatty rabbits. Due to the higher ratio of total litter loss and suckling mortality in the case of fatty rabbits the litter size at 21 days differed notably, but again not significantly. In the offsprings of the F1 generation it was found that the fat content estimated and also the ratio of scapular and abdominal fat to the live weight calculated differed significantly (P < 0.05) from each other in the two experimental groups. The estimated fat content was 42% higher in the offsprings of fatty than in the offsprings of non-fatty rabbits. The differences in the ratio of the scapular and abdominal fat content to the live weight were 26% and 51%, respectively.