Animal - Open Space最新文献

Due to the evolution of welfare laws and the search for novel methods to study pig microbiota, the development of precise and non-invasive sampling methods is key to studying the microbial communities that inhabit the guts of pigs. Administering swallowable devices to pigs is always a challenge due to factors such as anatomy, the requirement for specific materials, and the need to restrain the animals. In this study, we describe a step-by-step protocol on how to administer Capsule for Sampling (CapSa), a biocompatible non-invasive device to study pig’s microbiota without harming the animals. The validation of the protocol was done through two different studies. In Study 1, 92 Swiss Large White pigs (BW: 6.45–71.3 kg) were administered two capsules each and monitored for the following 3 days for capsule retrieval. On day 3, all pigs were euthanised to locate the missing capsules directly from their gastrointestinal tracts. In Study 2, 16 Swiss Large White pigs were selected at weaning and administered CapSas at five different timepoints (T1: 52 ± 3; T2: 70 ± 3; T3: 83 ± 3; T4: 110 ± 3; T5: 126 ± 3 days of age). To retrieve the capsules in the faeces, pigs were monitored 3 days postadministration. At T5, the pigs were slaughtered, and CapSas that were not found in the faeces, termed as missing CapSas, were retrieved from their gastrointestinal tracts. The protocol entails acclimation of the animals, housing modifications, administration of a prokinetic agent (prucalopride) to facilitate gastric emptying, and oesophageal intubations to overcome challenges related to administration, gastric blockage, and retrieval of the capsules. In Study 1, 46.74% of the administered CapSas were found in the faeces within 72 h postadministration, with 47.67% retrieved within the first 24 h, and 28.26% were located in the stomach. The CapSa retrieval was lowest in light pigs (<12 kg). In Study 2, 75.6% of CapSas were recovered in the faeces within 72 h postadministration, with 51.23% retrieved within the first 24 h. The CapSa retrieval rates varied depending on the administration time point being lowest at T1 and T3 and highest at T2 with intermediate values at T4 and T5. In both studies, the pH levels were affected by transit time (P < 0.01), resulting in a more acidic content when capsules were expelled after 36–40 h. To the contrary, the volume of the CapSa content was never affected by transit time (P < 0.05). In both studies, postmortem observations showed no health-related issues except one pig from Study 2 excluded due to respiratory distress. The present study describes a valid procedure for administering CapSa or any other swallowable devices in pigs. Moreover, this procedure is applicable to singular and repetitive administrations over the lifespan of pigs.

Measuring individual intake in animals raised in groups is a paramount aspect for different fields of animal production, both with a direct implication and relevance on the production itself, i.e. within breeding programmes for the improvement of feed efficiency; or for research in different disciplines such as animal behaviour or animal nutrition. The rabbit is one of the few species for which there is no device for measuring this trait. Thus, we aimed to design and manufacture a feeding device (eFeederRab) allowing such recording. In the present study, we describe the methods behind the tool we have developed, accompanying the description with a set of descriptive statistics showing the performance of the tool. We use records from 430 animals belonging to lines selected for different feed efficiency criteria − some of them raised using the eFeederRab -, as well as from their control unselected population. Measurements were taken from 35-38 to 56–59 days of age. The lines selected for reducing residual feed intake clearly show a lower daily feed intake, 8–15% when the lines were compared using eFeederRab, and 7–10% when the lines were compared using conventional feeders. These are clear indications about the validity of the device for recording data to be used in selection to improve feed efficiency, i.e., biologically meaningful records. In spite of the biological relevance of the recorded data, when comparing performances of the lines raised using eFeederRab or conventional feeders, it was evident that feed intake was reduced by around 12–20% when using the electronic feeder, with the subsequence growth penalization. Note however that this penalty is proportional to the intake; therefore, the feed conversion ratio remains fairly similar (2.99–3.13) between the two types of feeders also reflecting the expected tendency according to the different selection criteria across lines. We hypothesise that this reduction in the intake is a consequence of the less comfortable eating posture that eFeederRab imposes: each animal must eat alone and inside a tunnel for leading the animals one by one towards the feeder to grant their proper identification by radio frequency. We can conclude that although the eFeederRab is a device with different animal feeding conditions than those on conventional feeder, the records, despite being noisy, can be successfully used to improve the genetic selection of feed efficiency in rabbits.

Digestible energy (DE) accounts for the major fraction of the energy content of hay fed to equines, but DE measurements are difficult to carry out, and researchers have developed models for predicting the DE content of hays for horses from their chemical composition. Digestible energy varies depending on botanical family, species, and agronomic and climatic conditions. A database of 61 hays harvested in a temperate zone (32 natural grassland hays, 16 grass hays and 13 lucerne hays) was set up from studies carried out at the French National Institute of Agricultural Research (INRAe) or extracted from the literature using a similar methodological corpus, to test the relevance of crude fibre (CF), NDF, ADF, total free reducing sugars (TFRS), CP as potential criteria for the prediction of organic matter digestibility (OMD), energy digestibility (ED) and digestible energy (DE). Models were developed for natural grassland hay, grass hay and lucerne hay. The adjusted cross-validation R² values (R²CV) of the models obtained using CF, ADF or NDF as single variables or in combination with CP for the prediction of OMD, ED and DE of natural grassland hay ranged from 0.84 to 0.86, from 0.83 to 0.86 and from 0.82 to 0.84, respectively. For grass hay, the R²CV were lower and ranged from 0.65 to 0.71, from 0.63 to 0.71 and from 0.62 to 0.68, for the prediction of OMD, ED and DE, respectively. Finally, for lucerne hay, the R²CV ranged from 0.65 to 0.72, from 0.34 to 0.74 and from 0.25 to 0.67, for the prediction of OMD, ED and DE, respectively. The R²CV of the prediction models of ED and DE were more heterogeneous for lucerne hay than for grassland and grass hay. The TFRS content of hay was never a significant predictive variable of OMD, ED or DE, either as single variable or combined with any cell wall content criterion. The models obtained in the present study improved those proposed by INRA to date.