Correlated signatures of social behavior in cerebellum and anterior cingulate cortex

The cerebellum has been implicated in the regulation of social behavior. Its influence is thought to arise from communication, via the thalamus, to forebrain regions integral in the expression of social interactions, including the anterior cingulate cortex (ACC). However, the signals encoded or the nature of the communication between the cerebellum and these brain regions is poorly understood. Here, we describe an approach that overcomes technical challenges in exploring the coordination of distant brain regions at high temporal and spatial resolution during social behavior. We developed the E-Scope, an electrophysiology-integrated miniature microscope, to synchronously measure extracellular electrical activity in the cerebellum along with calcium imaging of the ACC. This single coaxial cable device combined these data streams to provide a powerful tool to monitor the activity of distant brain regions in freely behaving animals. During social behavior, we recorded the spike timing of multiple single units in cerebellar right Crus I (RCrus I) Purkinje cells (PCs) or dentate nucleus (DN) neurons while synchronously imaging calcium transients in contralateral ACC neurons. We found that during social interactions a significant subpopulation of cerebellar PCs were robustly inhibited, while most modulated neurons in the DN were activated, and their activity was correlated with positively modulated ACC neurons. These distinctions largely disappeared when only non-social epochs were analyzed suggesting that cerebellar-cortical interactions were behaviorally specific. Our work provides new insights into the complexity of cerebellar activation and co-modulation of the ACC during social behavior and a valuable open-source tool for simultaneous, multimodal recordings in freely behaving mice.

Correlated signatures of social behavior in cerebellum and anterior cingulate cortex

The cerebellum has been implicated in the regulation of social behavior. Its influence is thought to arise from communication, via the thalamus, to forebrain regions integral in the expression of social interactions, including the anterior cingulate cortex (ACC). However, the signals encoded or the nature of the communication between the cerebellum and these brain regions is poorly understood. Here, we describe an approach that overcomes technical challenges in exploring the coordination of distant brain regions at high temporal and spatial resolution during social behavior. We developed the E-Scope, an electrophysiology-integrated miniature microscope, to synchronously measure extracellular electrical activity in the cerebellum along with calcium imaging of the ACC. This single coaxial cable device combined these data streams to provide a powerful tool to monitor the activity of distant brain regions in freely behaving animals. During social behavior, we recorded the spike timing of multiple single units in cerebellar right Crus I (RCrus I) Purkinje cells (PCs) or dentate nucleus (DN) neurons while synchronously imaging calcium transients in contralateral ACC neurons. We found that during social interactions a significant subpopulation of cerebellar PCs were robustly inhibited, while most modulated neurons in the DN were activated, and their activity was correlated with positively modulated ACC neurons. These distinctions largely disappeared when only non-social epochs were analyzed suggesting that cerebellar-cortical interactions were behaviorally specific. Our work provides new insights into the complexity of cerebellar activation and co-modulation of the ACC during social behavior and a valuable open-source tool for simultaneous, multimodal recordings in freely behaving mice.

Hippocampal place cell remapping occurs with memory storage of aversive experiences

Aversive stimuli can cause hippocampal place cells to remap their firing fields, but it is not known whether remapping plays a role in storing memories of aversive experiences. Here we addressed this question by performing in-vivo calcium imaging of CA1 place cells in freely behaving rats (n=14). Rats were first trained to prefer a short path over a long path for obtaining food reward, then trained to avoid the short path by delivering a mild footshock. Remapping was assessed by comparing place cell population vector similarity before acquisition versus after extinction of avoidance. Some rats received shock after systemic injections of the amnestic drug scopolamine at a dose (1 mg/kg) that impaired avoidance learning but spared spatial tuning and shock-evoked responses of CA1 neurons. Place cells remapped significantly more following remembered than forgotten shocks (drug-free versus scopolamine conditions); shock-induced remapping did not cause place fields to migrate toward or away from the shocked location and was similarly prevalent in cells that were responsive versus non-responsive to shocks. When rats were exposed to a neutral barrier rather than aversive shock, place cells remapped significantly less in response to the barrier. We conclude that place cell remapping occurs in response to events that are remembered rather than merely perceived and forgotten, suggesting that reorganization of hippocampal population codes may play a role in storing memories for aversive events.

Whole-genome resequencing of the native sheep provides insights into the microevolution and identifies genes associated with reproduction traits

BACKGROUND

Sheep genomes undergo numerous genes losses, gains and mutation that generates genome variability among breeds of the same species after long time natural and artificial selection. However, the microevolution of native sheep in northwest China remains elusive. Our aim was to compare the genomes and relevant reproductive traits of four sheep breeds from different climatic environments, to unveil the selection challenges that this species cope with, and the microevolutionary differences in sheep genomes. Here, we resequenced the genomes of 4 representative sheep breeds in northwest China, including Kazakh sheep and Duolang sheep of native breeds, and Hu sheep and Suffolk sheep of exotic breeds with different reproductive characteristics.

RESULTS

We found that these four breeds had a similar expansion experience from ~ 10,000 to 1,000,000 years ago. In the past 10,000 years, the selection intensity of the four breeds was inconsistent, resulting in differences in reproductive traits. We explored the sheep variome and selection signatures by F_ST and θπ. The genomic regions containing genes associated with different reproductive traits that may be potential targets for breeding and selection were detected. Furthermore, non-synonymous mutations in a set of plausible candidate genes and significant differences in their allele frequency distributions across breeds with different reproductive characteristics were found. We identified PAK1, CYP19A1 and PER1 as a likely causal gene for seasonal reproduction in native sheep through qPCR, Western blot and ELISA analyses. Also, the haplotype frequencies of 3 tested gene regions related to reproduction were significantly different among four sheep breeds.

CONCLUSIONS

Our results provide insights into the microevolution of native sheep and valuable genomic information for identifying genes associated with important reproductive traits in sheep.

FPGA-Based In-Vivo Calcium Image Decoding for Closed-Loop Feedback Applications

Miniaturized calcium imaging is an emerging neural recording technique that has been widely used for monitoring neural activity on a large scale at a specific brain region of rats or mice. Most existing calcium-image analysis pipelines operate offline. This results in long processing latency, making it difficult to realize closed-loop feedback stimulation for brain research. In recent work, we have proposed an FPGA-based real-time calcium image processing pipeline for closed-loop feedback applications. It can perform real-time calcium image motion correction, enhancement, fast trace extraction, and real-time decoding from extracted traces. Here, we extend this work by proposing a variety of neural network based methods for real-time decoding and evaluate the tradeoff among these decoding methods and accelerator designs. We introduce the implementation of the neural network based decoders on the FPGA, and show their speedup against the implementation on the ARM processor. Our FPGA implementation enables the real-time calcium image decoding with sub-ms processing latency for closed-loop feedback applications.

Theta oscillations in anterior cingulate cortex and orbitofrontal cortex differentially modulate accuracy and speed in flexible reward learning

Flexible reward learning relies on frontal cortex, with substantial evidence indicating that anterior cingulate cortex (ACC) and orbitofrontal cortex (OFC) subregions play important roles. Recent studies in both rat and macaque suggest theta oscillations (5-10 Hz) may be a spectral signature that coordinates this learning. However, network-level interactions between ACC and OFC in flexible learning remain unclear. We investigated the learning of stimulus-reward associations using a combination of simultaneous in vivo electrophysiology in dorsal ACC and ventral OFC, partnered with bilateral inhibitory DREADDs in ACC. In freely behaving male and female rats and using a within-subject design, we examined accuracy and speed of response across distinct and precisely defined trial epochs during initial visual discrimination learning and subsequent reversal of stimulus-reward contingencies. Following ACC inhibition, there was a propensity for random responding in early reversal learning, with correct vs. incorrect trials distinguished only from OFC, not ACC, theta power differences in the reversal phase. ACC inhibition also hastened incorrect choices during reversal. This same pattern of change in accuracy and speed was not observed in viral control animals. Thus, characteristics of impaired reversal learning following ACC inhibition are poor deliberation and weak theta signaling of accuracy in this region. The present results also point to OFC theta oscillations as a prominent feature of reversal learning, unperturbed by ACC inhibition.

Genome-Wide Association Studies of Live Weight at First Breeding at Eight Months of Age and Pregnancy Status of Ewe Lambs

This study estimated genetic parameters and identified candidate genes associated with live weight, and the occurrence of pregnancy in 1327 Romney ewe lambs using genome-wide association studies. Phenotypic traits considered were the occurrence of pregnancy in ewe lambs and live weight at eight months of age. Genetic parameters were estimated, and genomic variation was assessed using 13,500 single-nucleotide polymorphic markers (SNPs). Ewe lamb live weight had medium genomic heritability and was positively genetically correlated with occurrence of pregnancy. This suggests that selection for heavier ewe lambs is possible and would likely improve the occurrence of pregnancy in ewe lambs. No SNPs were associated with the occurrence of pregnancy; however, three candidate genes were associated with ewe lamb live weight. Tenascin C (TNC), TNF superfamily member 8 (TNFSF8) and Collagen type XXVIII alpha 1 chain (COL28A1) are involved in extracellular matrix organization and regulation of cell fate in the immune system. TNC may be involved in ewe lamb growth, and therefore, could be of interest for selection of ewe lamb replacements. The association between ewe lamb live weight and TNFSF8 and COL28A1 is unclear. Further research is needed using a larger population to determine whether the genes identified can be used for genomic selection of replacement ewe lambs.

Association of Single Nucleotide Polymorphism in the DGAT1 Gene with the Fatty Acid Composition of Cows Milked Once and Twice a Day

A single nucleotide polymorphism (SNP) rs109421300 of the diacylglycerol acyltransferase 1 (DGAT1) on bovine chromosome 14 is associated with fat yield, fat percentage, and protein percentage. This study aimed to investigate the effect of SNP rs109421300 on production traits and the fatty acid composition of milk from cows milked once a day (OAD) and twice a day (TAD) under New Zealand grazing conditions. Between September 2020 and March 2021, 232 cows from a OAD herd and 182 cows from a TAD herd were genotyped. The CC genotype of SNP rs109421300 was associated with significantly (p < 0.05) higher fat yield, fat percentage, and protein percentage, and lower milk and protein yields in both milking frequencies. The CC genotype was also associated with significantly (p < 0.05) higher proportions of C16:0 and C18:0, higher predicted solid fat content at 10 °C (SFC₁₀), and lower proportions of C4:0 and C18:1 cis-9 in both milking frequencies. The association of SNP with fatty acids was similar in both milking frequencies, with differences in magnitudes. The SFC₁₀ of cows milked OAD was lower than cows milked TAD for all three SNP genotypes suggesting the suitability of OAD milk for producing easily spreadable butter. These results demonstrate that selecting cows with the CC genotype is beneficial for New Zealand dairy farmers with the current payment system, however, this would likely result in less spreadable butter.

Genetic and phenotypic relationships between ewe reproductive performance and wool and growth traits in Uruguayan Ultrafine Merino sheep

This study reports genetic parameters for yearling and adult wool and growth traits, and ewe reproductive performance. Data were sourced from an Uruguayan Merino flock involved in a long-term selection program focused on reduced fibre diameter (FD), and increased clean fleece weight (CFW) and live weight (LW). Pedigree and performance data from approximately 5,700 mixed-sex yearling lambs and 2,000 mixed-age ewes born between 1999 and 2019 were analysed. The number of records ranged from 1,267 to 5,738 for yearling traits, and from 1,931 to 7,079 for ewe productive and reproductive performance. Data on yearling and adult wool traits, LW and body condition score (BCS), yearling eye muscle area (Y_EMA), and fat thickness (Y_FAT), and several reproduction traits were analysed. The genetic relationships between FD and reproduction traits were not different from zero. Moderate unfavourable genetic correlations were found between adult CFW and ewe lifetime reproduction traits (-0.34 ± 0.08 and -0.33 ± 0.09 for total number of lambs weaned and total lamb live weight at weaning, respectively). There were moderate to strong positive genetic correlations between yearling LW and all reproduction traits other than ewe rearing ability (-0.08 ± 0.11) and pregnancy rate (0.18 ± 0.08). The genetic correlations between Y_EMA and reproduction traits were positive and ranged from 0.15 to 0.49. Moderate unfavourable genetic correlations were observed between yearling FD and Y_FAT and between adult FD and BCS at mating (0.31 ± 0.12 and 0.23 ± 0.07, respectively). The genetic correlations between adult fleece weight and ewe BCS at different stages of the cycle were negative, but generally not different from zero. This study shows that selection for reduced FD is unlikely to have any effect on reproduction traits. Selection for increased yearling LW and Y_EMA will improve ewe reproductive performance. On the other hand, selection for increased adult CFW will reduce ewe reproductive performance, whereas selection for reduced FD will negatively impact on body fat levels. Although unfavourable genetic relationships between wool traits and both FAT and ewe reproductive performance existed, simultaneous improvements in the traits would occur using appropriately designed indexes.

A hardware system for real-time decoding of in vivo calcium imaging data

Epifluorescence miniature microscopes ('miniscopes') are widely used for in vivo calcium imaging of neural population activity. Imaging data are typically collected during a behavioral task and stored for later offline analysis, but emerging techniques for online imaging can support novel closed-loop experiments in which neural population activity is decoded in real time to trigger neurostimulation or sensory feedback. To achieve short feedback latencies, online imaging systems must be optimally designed to maximize computational speed and efficiency while minimizing errors in population decoding. Here we introduce DeCalciOn, an open-source device for real-time imaging and population decoding of in vivo calcium signals that is hardware compatible with all miniscopes that use the UCLA Data Acquisition (DAQ) interface. DeCalciOn performs online motion stabilization, neural enhancement, calcium trace extraction, and decoding of up to 1024 traces per frame at latencies of <50 ms after fluorescence photons arrive at the miniscope image sensor. We show that DeCalciOn can accurately decode the position of rats (n = 12) running on a linear track from calcium fluorescence in the hippocampal CA1 layer, and can categorically classify behaviors performed by rats (n = 2) during an instrumental task from calcium fluorescence in orbitofrontal cortex. DeCalciOn achieves high decoding accuracy at short latencies using innovations such as field-programmable gate array hardware for real-time image processing and contour-free methods to efficiently extract calcium traces from sensor images. In summary, our system offers an affordable plug-and-play solution for real-time calcium imaging experiments in behaving animals.

Genomic Regions Associated with Wool, Growth and Reproduction Traits in Uruguayan Merino Sheep

The aim of this study was to identify genomic regions and genes associated with the fiber diameter (FD), clean fleece weight (CFW), live weight (LW), body condition score (BCS), pregnancy rate (PR) and lambing potential (LP) of Uruguayan Merino sheep. Phenotypic records of approximately 2000 mixed-age ewes were obtained from a Merino nucleus flock. Genome-wide association studies were performed utilizing single-step Bayesian analysis. For wool traits, a total of 35 genomic windows surpassed the significance threshold (PVE ≥ 0.25%). The proportion of the total additive genetic variance explained by those windows was 4.85 and 9.06% for FD and CFW, respectively. There were 42 windows significantly associated with LWM, which collectively explained 43.2% of the additive genetic variance. For BCS, 22 relevant windows accounted for more than 40% of the additive genetic variance, whereas for the reproduction traits, 53 genomic windows (24 and 29 for PR and LP, respectively) reached the suggestive threshold of 0.25% of the PVE. Within the top 10 windows for each trait, we identified several genes showing potential associations with the wool (e.g., IGF-1, TGFB2R, PRKCA), live weight (e.g., CAST, LAP3, MED28, HERC6), body condition score (e.g., CDH10, TMC2, SIRPA, CPXM1) or reproduction traits (e.g., ADCY1, LEPR, GHR, LPAR2) of the mixed-age ewes.

Mass Spectrometry-Based Lipidomics of Brown Adipose Tissue and Plasma of New-Born Lambs Subjected to Short-Term Cold Exposure

During cold exposure, brown adipose tissue (BAT) holds the key mechanism in the generation of heat, thus inducing thermogenic adaptation in response to cooler environmental changes. This process can lead to a major lipidome remodelling in BAT, where the increase in abundance of many lipid classes plays a significant role in the thermogenic mechanisms for heat production. This study aimed to identify different types of lipids, through liquid chromatography-mass spectrometry (LC-MS), in BAT and plasma during a short-term cold challenge (2-days), or not, in new-born lambs. Fifteen new-born Romney lambs were selected randomly and divided into three groups: Group 1 (n = 3) with BAT and plasma obtained within 24 h after birth, as a control; Group 2 (n = 6) kept indoors for two days at an ambient temperature (20-22 °C) and Group 3 (n = 6) kept indoors for two days at a cold temperature (4 °C). Significant differences in lipid composition of many lipid categories (such as glycerolipids, glycerophospholipids, sphingolipids and sterol lipids) were observed in BAT and plasma under cold conditions, compared with ambient conditions. Data obtained from the present study suggest that short-term cold exposure induces profound changes in BAT and plasma lipidome composition of new-born lambs, which may enhance lipid metabolism via BAT thermogenic activation and adipocyte survival during cold adaptation. Further analysis on the roles of these lipid changes, validation of potential biomarkers for BAT activity, such as LPC 18:1 and PC 35:6, should contribute to the improvement of new-born lamb survival. Collectively, these observations help broaden the knowledge on the variations of lipid composition during cold exposure.

The Flagellar Transcriptional Regulator FtcR Controls Brucella melitensis 16M Biofilm Formation via a betI-Mediated Pathway in Response to Hyperosmotic Stress

The expression of flagellar proteins in Brucella species likely evolved through genetic transference from other microorganisms, and contributed to virulence, adaptability, and biofilm formation. Despite significant progress in defining the molecular mechanisms behind flagellar gene expression, the genetic program controlling biofilm formation remains unclear. The flagellar transcriptional factor (FtcR) is a master regulator of the flagellar system’s expression, and is critical for B. melitensis 16M’s flagellar biogenesis and virulence. Here, we demonstrate that FtcR mediates biofilm formation under hyperosmotic stress. Chromatin immunoprecipitation with next-generation sequencing for FtcR and RNA sequencing of ftcR-mutant and wild-type strains revealed a core set of FtcR target genes. We identified a novel FtcR-binding site in the promoter region of the osmotic-stress-response regulator gene betI, which is important for the survival of B. melitensis 16M under hyperosmotic stress. Strikingly, this site autoregulates its expression to benefit biofilm bacteria’s survival under hyperosmotic stress. Moreover, biofilm reduction in ftcR mutants is independent of the flagellar target gene fliF. Collectively, our study provides new insights into the extent and functionality of flagellar-related transcriptional networks in biofilm formation, and presents phenotypic and evolutionary adaptations that alter the regulation of B. melitensis 16M to confer increased tolerance to hyperosmotic stress.

Molecular Detection of Zoonotic and Veterinary Pathogenic Bacteria in Pet Dogs and Their Parasitizing Ticks in Junggar Basin, North-Western China

Despite the recognized epidemiological importance of ticks as vectors for pathogens that cause numerous zoonotic and veterinary diseases, data regarding the pathogens of pet dogs and their parasitic ticks in the Junggar Basin are scarce. In this study, a total of 178 blood samples and 436 parasitic ticks were collected from pet dogs in Junggar Basin, Xinjiang Uygur Autonomous Region (XUAR), north-western China. All ticks were identified as Rhipicephalus turanicus sensu stricto (s.s.) according to morphological and molecular characteristics. Rh. turanicus s.s. ticks were collected from pet dogs in China for the first time. Seven tick-borne pathogens, such as Ehrlichia chaffeensis, Anaplasma phagocytophilum, Rickettsia massiliae, Candidatus R. barbariae, Brucella spp., Rickettsia sibirica, and Anaplasma ovis, were detected from ticks, whereas the first five bacteria were detected from blood samples of dogs. Brucella spp. was the most predominant pathogen in both blood samples and ticks of pet dogs, with the detection rates of 16.29 and 16.74%, respectively. Moreover, 17 ticks and 1 blood sample were co-infected with two pathogens, and 1 tick was co-infected with three pathogens. This study provided molecular evidence for the occurrence of Anaplasma spp., Ehrlichia spp., Rickettsia spp., and Brucella spp. circulating in pet dogs and their parasitic ticks in Junggar Basin, north-western China. These findings extend our knowledge of the tick-borne pathogens in pet dogs and their parasitic ticks in Central Asia; therefore, further research on these pathogens and their role in human and animal diseases is required.

Erratum to "Cumulative dairy cow genetic change from selection and crossbreeding over the last 2 decades in New Zealand closely aligns to model-based predictions published in 2000" (JDS Commun. 2:51-54)

[This corrects the article DOI: 10.3168/jdsc.2020-0043.].

Polymorphisms and association of GRM1, GNAQ, and HCRTR1 genes with seasonal reproduction and litter size in three sheep breeds

Litter size is one of the important economic traits of livestock. Seasonal estrus, ovulation, and lambing of sheep have severely restricted the development of sheep farming in Xinjiang China. The purpose of this study was to investigate the polymorphisms and genetic correlation between GRM1, GNAQ, and HCRTR1 genes and the seasonal reproduction and litter size in three sheep breeds. The DNA mixed pool sequencing and PCR-SSCP methods were used to detect single nucleotide polymorphisms (SNPs) of GRM1, GNAQ, and HCRTR1 genes in seasonal estrus (Kazakh and Chinese Merino [Xinjiang Junken type]) and perennial estrus (Hu) sheep breeds. The association between genetic polymorphism and litter size was also analyzed. The results showed that T945C in exon 2 of GRM1 gene, C589T in exon 2 of HCRTR1 gene and A191G in exon 2 of GNAQ gene were identified by Sanger sequencing, and three genotypes were existed in each SNP sites, which all belonged to the synonymous mutation. GRM1 (CC), GNAQ (GA) and HCRTR1 (TC) were the dominant genotypes of seasonal reproduction and litter size in Kazakh sheep and Chinese Merino sheep, respectively. While, in perennial estrus Hu sheep populations, the dominant genotypes were GRM1 (TC), GNAQ (GA) and HCRTR1 (TC) respectively, and association analysis was also confirmed the results. Above results implied that GRM1, GNAQ and HCRTR1 genes are significantly associated with lambing traits in Kazakh, Chinese Merino and Hu sheep. Among them, locus of GRM1 (T945C), GNAQ (A191G) and HCRTR1 (C589T) might be considered as a potential molecular marker which controls seasonal reproduction and litter size in sheep.

Rumen Development of Artificially-Reared Lambs Exposed to Three Different Rearing Regimens

The objective of this study was to examine the effect of three different rearing regimens on rumen development in lambs reared artificially. Romney ram lambs were randomly allocated to one of three treatments: commercial milk replacer fed to 57 d of age and high fibre concentrate pellets (HFP57); commercial milk replacer, high fibre concentrate pellets, and early weaning from milk replacer at 42 d of age (HFP42); high protein milk replacer from 2-16 d of age followed by commercial milk replacer, low fibre concentrate pellets, and early weaning from milk replacer at 42 d of age (LFP42). Lambs were slaughtered at 57 d of age. Volatile fatty acid content in rumen fluid at slaughter was analysed and rumen tissue samples were collected for histological examination. The rumen n-butyric content was greater (p < 0.05) in both LFP42 and HFP42 treatment lambs compared to HFP57 lambs. The n-valeric content was greater (p < 0.05) in LFP42 lambs compared to both HFP57 and HFP42 treatment lambs. Thickness of the rumen dorsal wall determined by ultrasound scanning at 49 d was greater (p < 0.05) in both HFP42 and LFP42 lambs compared to HFP57 lambs. There was an interaction (p < 0.05) between treatment and site of rumen tissue sampling on papillae width, density, and rumen muscular layer thickness. Collectively, early weaning and the provision of a low fibre pellet leads to improved rumen function and physical development.

Modulation of lateral septal and dorsomedial striatal neurons by hippocampal sharp-wave ripples, theta rhythm, and running speed

Single units were recorded in hippocampus, lateral septum (LS), and dorsomedial striatum (DMS) while freely behaving rats (n = 3) ran trials in a T‐maze task and rested in a holding bucket between trials. In LS, 28% (64/226) of recorded neurons were excited and 14% (31/226) were inhibited during sharp wave ripples (SWRs). LS neurons that were excited during SWRs fired preferentially on the downslope of hippocampal theta rhythm and had firing rates that were positively correlated with running speed; LS neurons that were inhibited during SWRs fired preferentially on the upslope of hippocampal theta rhythm and had firing rates that were negatively correlated with running speed. In DMS, only 3.3% (12/366) of recorded neurons were excited and 5.7% (21/366) were inhibited during SWRs. As in LS, DMS neurons that were excited by SWRs tended to have firing rates that were positively modulated by running speed, whereas DMS neurons that were inhibited by SWRs tended to have firing rates that were negatively modulated by running speed. But in contrast with LS, these two DMS subpopulations did not clearly segregate their spikes to different phases of the theta cycle. Based on these results and a review of prior findings, we discuss how concurrent activation of spatial trajectories in hippocampus and motor representations in LS and DMS may contribute to neural computations that support reinforcement learning and value‐based decision making.

Predicting ewe body condition score using adjusted liveweight for conceptus and fleece weight, height at withers, and previous body condition score record

The relationship between ewe body condition score (BCS) and liveweight (LW) has been exploited previously to predict the former from LW, LW-change, and previous BCS records. It was hypothesized that if fleece weight and conceptus-free liveweight and LW-change, and in addition, height at withers were used, the accuracy of current approaches to predicting BCS would be enhanced. Ewes born in 2017 (n = 429) were followed from 8 mo to approximately 42 mo of age in New Zealand. Individual ewe data were collected on LW and BCS at different stages of the annual production cycle (i.e., prebreeding, at pregnancy diagnosis, prelambing, and weaning). Additionally, individual lambing dates, ewe fleece weight, and height at withers data were collected. Linear regression models were fitted to predict current BCS at each ewe age and stage of the annual production cycle using two LW-based models, namely, unadjusted for conceptus weight and fleece weight (LW alone1) and adjusted (LW alone2) models. Furthermore, another two models based on a combination of LW, LW-change, previous BCS, and height at withers (combined models), namely, unadjusted (combined1) and adjusted for conceptus and fleece weight (combined2), were fitted. Combined models gave more accurate (with lower root mean square error: RMSE) BCS predictions than models based on LW records alone. However, applying adjusted models did not improve BCS prediction accuracy (or reduce RMSE) or improve model goodness of fit (R²) (P > 0.05). Furthermore, in all models, both LW-alone and combined models, a great proportion of variability in BCS, could not be accounted for (0.25 ≥ R² ≥ 0.83) and there was substantial prediction error (0.33 BCS ≥ RMSE ≥ 0.49 BCS) across age groups and stages of the annual production cycle and over time (years). Therefore, using additional ewe data which allowed for the correction of LW for fleece and conceptus weight and using height at withers as an additional predictor did not improve model accuracy. In fact, the findings suggest that adjusting LW data for conceptus and fleece weight offer no additional value to the BCS prediction models based on LW. Therefore, additional research to identify alternative methodologies to account for individual animal variability is still needed.

The Dome: A virtual reality apparatus for freely locomoting rodents

The cognitive map in the hippocampal formation of rodents and other mammals integrates multiple classes of sensory and motor information into a coherent representation of space. Here, we describe the Dome, a virtual reality apparatus for freely locomoting rats, designed to examine the relative contributions of various spatial inputs to an animal’s spatial representation. The Dome was designed to preserve the range of spatial inputs typically available to an animal in free, untethered locomotion while providing the ability to perturb specific sensory cues. We present the design rationale and corresponding specifications of the Dome, along with a variety of engineering and biological analyses to validate the efficacy of the Dome as an experimental tool to examine the interaction between visual information and path integration in place cells in rodents.

Associations among Mammary Ultrasound Measurements, Milk Yield of Non-Dairy Ewe Lambs and the Growth of Their Single Lambs

Simple Summary

Mammary internal structures were associated with milk yield in mature dairy ewes and lamb growth in ewe lambs. This experiment was designed to examine the association between mammary ultrasound measurements and milk yield in ewe lambs and the accuracy of using mammary ultrasound measurements to predict single lamb growth rates to weaning. Mammary internal structures were measured in 45 single-bearing ewe lambs at day 110 of pregnancy, week three (W3), five (W5), and seven (W7) of lactation and at weaning (L69). The ewe lambs were milked once at W3, W5 and W7 and the single lambs were weighed at birth, W3, W5, W7, and L69. The predictions of milk yield were moderate, and the predictions of lamb growth were high to moderate, indicating that mammary ultrasound was more accurate in predicting lamb growth than milk yield. Further investigations are required to identify better indicators of milk yield in ewe lambs.

Abstract

Mammary cistern size was positively correlated with milk yield of mature dairy ewes, but the association in ewe lambs is unknown. This experiment aimed to examine the associations between mammary ultrasound measurements and the milk yield of ewe lambs at one year of age and to determine the accuracy of using maternal mammary ultrasound to predict single lamb growth rates. Single-bearing ewe lambs (n = 45) were randomly selected and 30 were milked once at weeks three (W3), five (W5), and seven (W7) of lactation. Mammary ultrasound scans were performed at day 110 of pregnancy, W3, W5, W7, and weaning (L69). Single lambs (n = 30) were weighed at birth and at each mammary scanning event. Udder measurements explained 26.8%, 21.4%, and 38.4% of the variation in milk yield at W3, W5 and W7, respectively, and 63.5% and 36.4% of the variation in single lamb growth to W3 and to L69. This ultrasound technique was more accurate in predicting single lamb growth to W3 than milk yield and may enable the identification of pregnant ewe lambs whose progeny would have greater growth rates. More research is needed to identify accurate indicators of superior milk yield and determine whether ultrasound could be used to select ewe lambs.

miR-509-5p anti-infection response for mycoplasma pneumonia in sheep by targeting NF-κB pathway

MicroRNAs play a key role in Mannan-binding lectin-mediated resistance to Mycoplasma ovipneumoniae pneumonia, by regulating the translation of mRNAs of target genes, thereby regulating the immune response. Additionally, TRAF6 is a key molecule in Toll-like receptor signal transduction, which mediates inflammation and apoptosis signaling pathways and is widely involved in inflammation and immune response. While the molecular regulation mechanism has not been reported. In this study, we screened differentially expressed miRNAs and genes of Anti-infection for M. pneumonia on Sheep, through relevant bioinformatics analysis. Further, the effect of differential expression of NF-κB signaling pathway related genes on the molecular mechanism of M. pneumonia was detected. We used miRNA-mRNA integrated analysed, the target gene TRAF6 of miR-509-5p was selected. TRAF6 dual luciferase reporter vector was co-transfected into HEK 293T cells and primary sheep respiratory mucosal epithelial cells to detect changes in luciferase activity. qRT-PCR was used to analyze the effect of miR-509-5p on the expression and regulation of TRAF6 and other genes related to the NF-κB signaling pathway. The result confirmed that TRAF6 was a target gene of miR-509-5p. Compared with miR-509-5p-NC group, the luciferase activity of miR-509-5p group was significantly down-regulated (P < 0.01). Further, in sheep respiratory mucosal epithelial cells, miR-509-5p mimic could significantly down-regulate the fold change value of TRAF6 (P < 0.01). On the contrary, miR-509-5p-inhibitor up-regulated the fold change value of TRAF6 (P < 0.05). Interestingly, the expression levels of other genes were different. Among them, miR-509-5p mimic significantly up-regulated TLR4 and IRAK4 (P < 0.05), significantly down-regulated TAK1 (P < 0.05) and NF-κB (P < 0.01). miR-509-5p-inhibitor significantly up-regulated NF-κB (P < 0.05) and TAK1 (P < 0.01). miR-509-5p targets TRAF6 to affect the expression of downstream genes, which negatively regulates the NF-κB pathway, thereby affecting the inflammatory response.

Comparative profiling of the resistance of different genotypes of mannose-binding lectin to Mycoplasma pneumoniae infection in Chinese Merino sheep based on high-throughput sequencing technology

Mannose-binding lectin (MBL) glycoproteins in blood can selectively recognise lectins on the surface of bacteria, and play an important role in natural immunity. Micro RNAs (miRNAs) are key molecules that regulate gene expression at the post-transcriptional level in vivo, and their pathways are specific and effective. Previous studies indicate that small RNAs such as miRNAs perform regulatory roles in immunology. Herein, we investigated differential expression of miRNAs during MBL protein immunotherapy in sheep following treatment with different MBL genotypes (resistant and susceptible), and identified miRNAs linked to different target genes and pathways. RNA was extracted from liver tissue of resistant and susceptible sheep, miRNAs were identified by high-throughput sequencing, and differentially expressed miRNAs were analysed by SOAP to predict target genes and biological pathways. Results: Some miRNAs (oar-mir-143, oar-mir-10b, oar-mir-382, oar-mir-432 and oar-mir-379) were up-regulated, while others were down-regulated. GPATCH3 and DNAJC5 were predicted target genes of oar-mir-379, DMRT1 and GATA4 were linked to oar-mir-382, and oar-mir-432 was associated with STAT2, DMRT1 and ATG16L1. Identification of miRNAs differentially expressed in resistant and susceptible sheep may expand our understanding of miRNAs in immune regulation, and the role of MBL in innate immunity.

Characterization of muscle development and gene expression in early embryos of chicken, quail, and their hybrids

Myogenesis is a complex, regulated process that involves myoblast proliferation, migration, adhesion, and fusion into myotubes. To investigate early development of embryonic muscles and the expression of regulatory genes during myogenesis in chicken, quail and their hybrids, meat-breeding cocks and egg-breeding cocks were selected as male parents, quails were used as female parents. Their offspring were meat and egg hybrids via Artificial insemination. We measured expression of MUSTN1, IGF-1, and PDK4 using qRT-PCR. We examined muscle fiber diameter using scanning electron microscopy. The results showed that muscle development was two days slower in chicken, egg hybrid, and meat hybrid than in quail. Muscle fiber spacing was the largest in chicken, followed by meat hybrid, egg hybrid, and quail. A similar trend was obtained for muscle fiber diameter. Additionally, muscle fiber diameter increased with embryogenesis. The sarcomere was present on day 17 of incubation in quail, but not in the other species. MUSTN1 could up-regulated IGF-1 by activating PI3K/Akt. IGF-1 expression was consistent with myoblast proliferation and myotube fusion. PDK4 was expressed from E7 to E17. The first peak was reached on E10, egg hybrid and meat hybrid reached their peak at E15. PDK4 is involved in the early proliferation and differentiation of muscle, thereby affecting muscle growth and development. Our findings demonstrated that MUSTN1, IGF-1 and PDK4 genes are expressed to varying levels in breast muscle of chicken, quail, egg hybrid and meat hybrid during the embryonic period. Interestingly, with increasing embryonic age, muscle development was approximately 48 h faster in quail than in other species. We speculated that MUSTN1, IGF-1 and PDK4 genes may be the main candidate genes that cause differences in poultry muscle traits, but the molecular regulation mechanisms need to be further studied. Our findings shed some light on the avian embryo muscle formation and molecular breeding of poultry muscle traits, which provide theoretical basis for poultry breeding.

Effect of Dietary Folic Acid Supplementation during Pregnancy on Blood Characteristics and Milk Composition of Ewes

The objective of the present study was to investigate the dynamic change of serum parameters and milk composition by dietary FA supplementation with ewes with different litter size from mating to lambing. The ewes were divided into six treatments (TW-CON, TW-F16, TW-F32, TR-CON, TR-F16, TR-F32) according to dietary FA levels (control, CON; 16 or 32 mg·kg^-1 rumen-protect-FA supplementation, F16 and F32) and litter size (twin born, TW; and triplet born, TR). In serum, the concentration of folate increased linearly with dietary FA supplementation (P < 0.05), regardless of the litter size, they showed a quadratic response to gestation progression (P < 0.05). With dietary FA addition, IGFI-I levels significant increased from late gestation to after lambing (P < 0.05), and linearly increased immunoglobulin during the perinatal period (P < 0.05). In colostrum and milk at d 15, the content of folate, lactoferrin, and IgG were affected positively by FA supplementation (P < 0.05). IgG was higher in the TW group than TR in colostrum (P < 0.05), and lactoferrin in TW was lower than TR in milk of d 15 (P < 0.05). FA supplementation increased protein content in colostrum (P < 0.05), while it had no effect on the fat, lactose, and BUN of colostrum and milk of d 15 (P > 0.05). These results suggest that FA supplementation during gestation could regulate maternal blood metabolism and contribute to milk immune composition.

An uncertainty principle for neural coding: Conjugate representations of position and velocity are mapped onto firing rates and co-firing rates of neural spike trains

The hippocampal system contains neural populations that encode an animal's position and velocity as it navigates through space. Here, we show that such populations can embed two codes within their spike trains: a firing rate code (R) conveyed by within‐cell spike intervals, and a co‐firing rate code (R˙) conveyed by between‐cell spike intervals. These two codes behave as conjugates of one another, obeying an analog of the uncertainty principle from physics: information conveyed in R comes at the expense of information in R˙, and vice versa. An exception to this trade‐off occurs when spike trains encode a pair of conjugate variables, such as position and velocity, which do not compete for capacity across R and R˙. To illustrate this, we describe two biologically inspired methods for decoding R and R˙, referred to as sigma and sigma‐chi decoding, respectively. Simulations of head direction and grid cells show that if firing rates are tuned for position (but not velocity), then position is recovered by sigma decoding, whereas velocity is recovered by sigma‐chi decoding. Conversely, simulations of oscillatory interference among theta‐modulated “speed cells” show that if co‐firing rates are tuned for position (but not velocity), then position is recovered by sigma‐chi decoding, whereas velocity is recovered by sigma decoding. Between these two extremes, information about both variables can be distributed across both channels, and partially recovered by both decoders. These results suggest that populations with different spatial and temporal tuning properties—such as speed versus grid cells—might not encode different information, but rather, distribute similar information about position and velocity in different ways across R and R˙. Such conjugate coding of position and velocity may influence how hippocampal populations are interconnected to form functional circuits, and how biological neurons integrate their inputs to decode information from firing rates and spike correlations.

Effect of adding crude glycerine to diets with feed additives on the feed intake, ruminal degradability, volatile fatty acid concentrations and in vitro gas production of feedlot Nellore cattle

The effects of adding crude glycerine with sodium monensin or essential oils to beef cattle diets on the intake, degradability of DM and nutrients, rumen concentration of volatile fatty acids (VFA) and in vitro gas production were evaluated. Five ruminally cannulated Nellore steers were randomly assigned to a 5 × 5 Latin square design. The treatments were as follows: CONT, without crude glycerine and additives; EO, with essential oils and without crude glycerine; MON, with sodium monensin and without crude glycerine; EOG, with essential oils and crude glycerine; MONG, with sodium monensin and crude glycerine. Treatments with essential oil and sodium monensin increased the NDF and STC intake and the DM degradability. When crude glycerine was combined with either sodium monensin or essential oil, there was a reduction in DM, NDF and STC intake and an increase in DM and CP degradability of the diets. The adding crude glycerine to essential oil diets reduced the CH₄ production. Sodium monensin treatments reduced DM and NDF intake and the production of total gas, CH₄ , total VFA and acetic acid concentration. In conclusion, the adding crude glycerine (200 g/kg DM) with either sodium monensin (0.03 g/kg DM) or essential oil (0.5 g/kg DM) can be utilized in diets for Nellore cattle without causing detrimental effects on feed intake and improving the DM degradability.

Parenteral administration of l-arginine to twin-bearing Romney ewes during late pregnancy is associated with reduced milk somatic cell count during early lactation

Maternal milk is the primary source of nutrition for suckling mammals, and its yield and composition are important determinants of survival during the early neonatal period. The objective of this study was to examine whether parenteral administration of l-Arg to twin-bearing ewes, during mid to late pregnancy, influenced prepartum maternal mammary gland development and subsequent lactation performance in the early postpartum period (14 d). At 80 d of pregnancy, multiparous Romney ewes were housed indoors in group pens, split into 2 cohorts, and fed a lucerne-based pellet diet, formulated to meet 100% of National Research Council-recommended requirements for twin-bearing pregnant ewes, once a day. Cohort 1 was administered l-Arg (72.7 mg/kg of live weight via i.v, 3 times a day) from d 100 of pregnancy until d 140. At d 140, ewes were euthanized and maternal mammary tissues were collected for analysis of the biochemical indices total DNA, RNA, protein, protein synthetic efficiency (protein:RNA), cell size (protein:DNA), transcriptional efficiency (RNA:DNA), and the abundance of mammalian target of rapamycin (mTOR) and mTOR^Ser2448 protein. Cohort 2 was administered an identical l-Arg regimen as cohort 1, but from d 100 until parturition. Milk was collected over a 14-d period (d 1, 4, 7, 10, and 14) to assess milk yield and composition. In cohort 1, total mammary DNA (cell number) tended to be higher in l-Arg ewes, with no change in total mammary RNA or protein content, biochemical indices of protein synthetic efficiency, cell size or transcriptional efficiency, or mTOR protein abundance or phosphorylation. In cohort 2, milk composition analysis from l-Arg ewes showed lower (d 7-14) milk somatic cell counts, greater crude protein percentage from d 7 to 10 but lower at d 14, and altered absolute concentrations of some free AA (d 7 and 14) compared with controls. We propose that parenteral administration of l-Arg during late pregnancy is associated with increased mammary gland cellular content and decreased somatic cell counts during early lactation.

Recalibration of path integration in hippocampal place cells

Hippocampal place cells are spatially tuned neurons that serve as elements of a 'cognitive map' in the mammalian brain1. To detect the animal's location, place cells are thought to rely upon two interacting mechanisms: sensing the position of the animal relative to familiar landmarks2,3 and measuring the distance and direction that the animal has travelled from previously occupied locations4-7. The latter mechanism-known as path integration-requires a finely tuned gain factor that relates the animal's self-movement to the updating of position on the internal cognitive map, as well as external landmarks to correct the positional error that accumulates8,9. Models of hippocampal place cells and entorhinal grid cells based on path integration treat the path-integration gain as a constant9-14, but behavioural evidence in humans suggests that the gain is modifiable15. Here we show, using physiological evidence from rat hippocampal place cells, that the path-integration gain is a highly plastic variable that can be altered by persistent conflict between self-motion cues and feedback from external landmarks. In an augmented-reality system, visual landmarks were moved in proportion to the movement of a rat on a circular track, creating continuous conflict with path integration. Sustained exposure to this cue conflict resulted in predictable and prolonged recalibration of the path-integration gain, as estimated from the place cells after the landmarks were turned off. We propose that this rapid plasticity keeps the positional update in register with the movement of the rat in the external world over behavioural timescales. These results also demonstrate that visual landmarks not only provide a signal to correct cumulative error in the path-integration system4,8,16-19, but also rapidly fine-tune the integration computation itself.

Spatial synchronization codes from coupled rate-phase neurons

During spatial navigation, the frequency and timing of spikes from spatial neurons including place cells in hippocampus and grid cells in medial entorhinal cortex are temporally organized by continuous theta oscillations (6-11 Hz). The theta rhythm is regulated by subcortical structures including the medial septum, but it is unclear how spatial information from place cells may reciprocally organize subcortical theta-rhythmic activity. Here we recorded single-unit spiking from a constellation of subcortical and hippocampal sites to study spatial modulation of rhythmic spike timing in rats freely exploring an open environment. Our analysis revealed a novel class of neurons that we termed 'phaser cells,' characterized by a symmetric coupling between firing rate and spike theta-phase. Phaser cells encoded space by assigning distinct phases to allocentric isocontour levels of each cell's spatial firing pattern. In our dataset, phaser cells were predominantly located in the lateral septum, but also the hippocampus, anteroventral thalamus, lateral hypothalamus, and nucleus accumbens. Unlike the unidirectional late-to-early phase precession of place cells, bidirectional phase modulation acted to return phaser cells to the same theta-phase along a given spatial isocontour, including cells that characteristically shifted to later phases at higher firing rates. Our dynamical models of intrinsic theta-bursting neurons demonstrated that experience-independent temporal coding mechanisms can qualitatively explain (1) the spatial rate-phase relationships of phaser cells and (2) the observed temporal segregation of phaser cells according to phase-shift direction. In open-field phaser cell simulations, competitive learning embedded phase-code entrainment maps into the weights of downstream targets, including path integration networks. Bayesian phase decoding revealed error correction capable of resetting path integration at subsecond timescales. Our findings suggest that phaser cells may instantiate a subcortical theta-rhythmic loop of spatial feedback. We outline a framework in which location-dependent synchrony reconciles internal idiothetic processes with the allothetic reference points of sensory experience.

Meta-analysis of lamb birth weight as influenced by pregnancy nutrition of multiparous ewes

Across the literature, there is large variation in lamb birth weight responses to changes in the ewe pregnancy nutrition. Much of this heterogeneity has been attributed to several factors inherent to each experiment; however, the relative contribution of these experimental factors has not yet been quantified. This meta-analysis aimed to systematically review the variation in lamb birth weight responses across nutritional studies involving adult multiparous ewes. Effect-sizes for individual studies were estimated using the unbiased estimator Hedges' g, whereby positive and negative values indicate heavier and lighter treatment lambs vs. controls, respectively. Heterogeneity varied between early-, mid- and late-pregnancy undernutrition studies (I2total [early pregnancy] = 19.90%, I2total [midpregnancy] = 52.10%, I2total [late pregnancy] = 68.70%). The small average effects for early- (0.04, highest posterior density [HPD] interval = -0.22, 0.28) and mid-pregnancy undernutrition (-0.15, HPD interval = -0.35, 0.05) suggest that if farmers anticipate a potential feed shortage, ewes can be allowed to lose weight providing nutrition is resumed to adequate levels later in pregnancy. On the contrary, late-pregnancy undernutrition was associated with a significant decrease in lamb birth weight (-0.72, HPD interval = -0.86, -0.55). Thus, management practices should focus on ensuring adequate nutrition in late pregnancy. Increasing lamb birth weight could be possible by feeding ewes above their pregnancy maintenance requirement (0.23, HPD interval = 0.002, 0.48), though the number of studies is limited and further research is needed.

Timing of exogenous progesterone administration is critical for embryo development and uterine gene expression in an ovine model of maternal constraint

Progesterone (P4) administration in early pregnancy enhances embryo growth in sheep but is associated with decreased embryo survival. This study examined the effects of exogenous P4 administered during specific time periods between pregnancy Day 0 and Day 6 to determine the critical time point for advancement of embryo growth without pregnancy loss and to examine Day 6 and Day 19 endometrial gene expression. Suffolk (S) embryos were transferred into Cheviot (C) ewes that received exogenous P4 (CP4) on Days 0–3 (CP40–3), Days 0–6 (CP40–6), Days 2–4 (CP42–4) or Days 3–6 (CP43–6). Additionally, S embryos were transferred to C and S ewes that did not receive P4 (CnP4 and SnP4). Day 19 embryos from CP4 ewes were longer (P < 0.05) than those from CnP4 ewes. CP42–4 ewes had embryos of similar size to those of CP40–3 and CP40–6 ewes but had higher pregnancy rates. There was altered expression of genes associated with embryo implantation and histotroph production: diacylglycerol-O-acyltransferase (DGAT2), hepatocyte growth factor (HGF) and prostaglandin endoperoxide synthase 2 (PTSG2) on Day 6 and endometrial galectin 15 (LGALS15) and mucin glycoprotein 1 (MUC1) on Day 19. This suggests that specific timing of P4 administration is critical to the enhanced embryo growth and survival observed. These findings provide a platform for further investigation aimed at advancing embryo development and survival.

Effect of exogenous progesterone on embryo size and ewe uterine gene expression in an ovine 'dam size' model of maternal constraint

Progesterone (P4), acting via its receptor, regulates uterine function and histotroph production, which are crucial to embryo growth. This study aimed to examine exogenous P4 effects on embryo size and differential endometrial gene expression at Day 19 of gestation using a 'dam size' sheep model of maternal constraint. Purebred Suffolk (S, genotypically large) embryos were transferred into recipient groups of Cheviot (C, genotypically small) or Suffolk ewes that had, or had not, been pre-treated with P4 from Days 0 to 6 of pregnancy. At Day 19S embryos were collected from four experimental groups: P4 pretreated S ewes (SP4; n=5), untreated S ewes (SnP4; n=15), P4 pretreated C ewes (CP4; n=7) and untreated C ewes (CnP4; n=21). Day-19 embryos from CP4 ewes were larger (P<0.05) than those from CnP4 ewes and similar in size (P>0.05) to embryos from SnP4 and SP4 ewes. Expression of mucin 1 (MUC1) and prostaglandin-endoperoxide synthase 2 (PTGS2) was upregulated in uterine horns ipsilateral to the corpus luteum from CP4 ewes. Prostaglandin receptor (PGR), MUC1 and PTGS2 expression was upregulated, whilst cathepsin L (CTSL) and radical S-adenosyl methionine domain-containing 2 (RSAD2) expression was downregulated in the ipsilateral horn of SP4 ewes. This suggests that pretreating ewes with exogenous P4 may alleviate early pregnancy maternal constraint via mechanisms that alter uterine function. However, further research is required to investigate the timing of P4 administration and its impact on conception rates.

Relationships between prenatal ewe traits, milk production, and preweaning performance of twin lambs

There is limited information on factors affecting twin lamb growth before weaning, which limits the options available to farmers to actively manage lamb growth. Data from 2 multiyear experiments involving 402 twin-bearing Romney ewes were used to evaluate the effects of prenatal ewe traits (live weight at mating and set stocking and BCS at mating and set stocking) and combined twin lamb birth weight on ewe milk production and lamb growth from birth to weaning as well as the proportion of variation in twin lamb growth that could be explained by these variables. Additionally, the effect of accumulated ewe milk yield over a 42-d period (MY; Days 0 to 42) and accumulated milk components (protein, fat, and lactose) on twin lamb growth were investigated. The effects of prenatal variables on MY, birth weight, and combined twin lamb live weight gain from Day 0 to 42 (LWG) were inconsistent across the 2 experiments. In addition, prenatal ewe traits ( < 0.05) explained less than 30% of the variation in MY and lamb growth from birth to weaning in both experiments. Combined twin lamb birth weight was positively ( < 0.001) correlated with MY ( = 0.34 and = 0.43 in Exp. 1 and 2, respectively). Combined twin lamb LWG was dependent on ewe MY ( = 0.43 for Exp. 1 and = 0.30 for Exp. 2). Lactose, fat, and milk CP yields explained 47 and 42% of the variation in lamb LWG in Exp. 1 and 2, respectively. Lactose and milk CP yield positively affected ( < 0.05) LWG in Exp. 1 and 2, respectively. Fat yield had a positive relationship with LWG in Exp. 1 and a negative relationship with LWG in Exp. 2. In conclusion, the measured prenatal ewe traits had a minimal effect on milk yield and twin lamb growth to weaning. Milk yield and composition explained the greatest proportion of variation in LWG. This suggests that farmers should select ewes with higher milk yields to maximize twin lamb growth to weaning. However, less than 50% of the variation in LWG and weaning live weight was explained by the measured ewe and lamb parameters. Therefore, further studies are required to determine additional ewe or lamb variables that control variation in twin lamb growth.

Effect of different feeding regimens on energy and protein utilization and partitioning for maintenance and growth in pre-weaned lambs reared artificially

Estimation of metabolizable energy (ME) requirement for maintenance (ME) and growth (ME) in pre-weaned lambs have been limited to milk-only fed lambs. This study aimed to determine energy and nitrogen metabolisability of milk and pellets when fed together, compare the growth and chemical body composition of lambs fed varying levels of pellets in addition to milk, and to estimate ME, ME, and the CP:ME ratio requirements for growth. The study included 32 twin-born Romney-cross ram lambs. Four lambs were slaughtered at 24 h post-partum to estimate initial body composition and the remaining 28 were assigned to 1 of 4 treatment groups of 7. Group 1 was fed milk replacer (MR) only; group 2 was fed MR and allowed ad libitum access to pellets; groups 3 and 4 were offered 30% and 60%, respectively of the average pellet intake of the ad libitum group the previous day while being fed MR. Milk replacer was fed as a proportion of the lamb's live weight (LW). Lambs from each treatment were placed in metabolic cages at 17 kg LW for 4 d to allow for total fecal and urine collection. All lambs were slaughtered at 18 kg LW. The ADG, ADG:ME ratio, stomach and liver weight, and rumen papillae lengths increased ( < 0.05) with increasing pellet intake. Increasing daily ME intake increased ( < 0.05) both daily energy and protein deposition but had no effect ( > 0.05) on fat deposition. However, the total chemical body composition was unaffected ( > 0.05) by dietary treatment. Digestibility of energy and N decreased ( < 0.05) with increasing ME intake. Percent energy and N retained for growth were 96% vs. 71% and 72% vs. 30% for milk and pellets, respectively. The ME and ME values obtained were 0.40 MJ ME/kg LW·d and 13.8 MJ ME/kg ADG, respectively. The CP:ME ratio of MR and pellet was 11.1 and 15.7, respectively. However, a simulation model suggested that lambs require a CP:ME ratio of 13.1 at 5 kg and 10.9 at 18 kg LW, indicating that protein intake may be limiting to lamb growth in early life and in excess by 18 kg LW. In conclusion, increasing pellet intake was associated with decreased N retention. The inclusion of pellets, however, improved the efficiency of ME utilization for growth in pre-weaned lambs and was beneficial for rumen development. The ME was higher than previously recommended values and the CP:ME intake of lambs does not match their requirements which may warrant further studies.

Gestation-related gene expression and protein localization in endometrial tissue of Suffolk and Cheviot ewes at gestation Day 19, after transfer of Suffolk or Cheviot embryos

The objective of this study was to investigate the gene expression of progesterone and estrogen receptor α (PR, ERα), insulin-like growth factor (IGF) 1, IGF-2, their receptor (IGFR1), IGF-binding proteins (BP) 1 to 6, insulin receptor, adiponectin receptors (AdipoR1/2), cyclooxygenase 2 (PTGS2), mucin 1 and to localize PR, ERα, IGF-1, IGFR1, PTGS2, and proliferating cellular nuclear antigen (PCNA) in the endometrium of pregnant (Day 19) Suffolk and Cheviot ewes carrying Suffolk and Cheviot embryos transferred within and reciprocally between breeds. Gene expression was determined by real-time quantitative polymerase chain reaction (RT-qPCR), and antigen determination was measured by immunohistochemistry in the luminal epithelium (LE), superficial and deep glands (SG, DG, respectively) and superficial and deep stroma. Gene expression of PR, IGF-1, IGFBP2, and IGFBP5 was higher in Suffolk than that in Cheviot ewes (P < 0.05). Greater abundance of IGF-2 and IGBP3 expression was found in Cheviot ewes carrying Cheviot embryos than Cheviot ewes carrying Suffolk embryos (P < 0.05). No staining for PR and ERα was observed in the LE, very scarce staining in SG and DG, whereas positive staining was observed in both superficial and deep stroma. No differences were found for PR staining, but Cheviot ewes had higher ERα staining intensity than Suffolk ewes (P < 0.05). Positive staining for IGF-1 was observed in all cell types except DG, and staining of IGFR1 was observed in all cell types. No differences among groups in staining were found for IGF-1 or IGFR1 in any cell type. Positive staining of PTGS2 was observed in LE and SG in all groups. An interaction between ewe and embryo breed affected PTGS2 staining (P < 0.05), whereby Cheviot ewes carrying Suffolk embryos had a lower PTGS2 staining than Suffolk ewes carrying Suffolk embryos. Positive staining of PCNA was found in LE and SG. Suffolk ewes carrying Suffolk embryos showed lower PCNA immunostaining than Cheviot ewes carrying Suffolk embryos (P < 0.05), whereas no differences were observed in ewes carrying Cheviot embryos. This study showed that gestation-related protein expression in the endometrium of Suffolk and Cheviot ewes is affected by both ewe and embryo breed at Day 19 of pregnancy.

Prefrontal infralimbic cortex mediates competition between excitation and inhibition of body movements during pavlovian fear conditioning

The infralimbic subregion of the prefrontal cortex (IL) is broadly involved in behavioral flexibility, risk assessment, and outcome reinforcement. In aversive conditioning tasks, the IL has been implicated in fear extinction and in mediating transitions between Pavlovian and instrumental responses. Here we examine the role of the IL in mediating transitions between two competing Pavlovian fear responses, conditioned motor inhibition (CMI) and conditioned motor excitation (CME). Rats were trained to fear an auditory conditioned stimulus (CS) by pairing it with periorbital shock to one eyelid (the unconditioned stimulus [US]). Trained animals exhibited CMI responses (movement suppression) to the CS when they had not recently encountered the US (>24 hr), but, after recent encounters with the US (<5 min), the CS evoked CME responses (turning in circles away from anticipated shock). Animals then received bilateral infusions of muscimol or picrotoxin to inactivate or hyperactivate the IL, respectively. Neither drug reliably affected CMI responses, but there was a bidirectional effect on CME responses; inactivation of the IL attenuated CME responses, whereas hyperactivation potentiated CME responses. These results provide evidence that activation of the IL may promote behavioral strategies that involve mobilizing the body and suppress strategies that involve immobilizing the body. © 2016 Wiley Periodicals, Inc.

Functional development of the adult ovine mammary gland--insights from gene expression profiling

Background

The mammary gland is a dynamic organ that undergoes dramatic physiological adaptations during the transition from late pregnancy to lactation. Investigation of the molecular basis of mammary development and function will provide fundamental insights into tissue remodelling as well as a better understanding of milk production and mammary disease. This is important to livestock production systems and human health.

Here we use RNA-seq to identify differences in gene expression in the ovine mammary gland between late pregnancy and lactation.

Results

Between late pregnancy (135 days of gestation ± 2.4 SD) and lactation (15 days post partum ± 1.27 SD) 13 % of genes in the sheep genome were differentially expressed in the ovine mammary gland. In late pregnancy, cell proliferation, beta-oxidation of fatty acids and translation were identified as key biological processes. During lactation, high levels of milk fat synthesis were mirrored by enrichment of genes associated with fatty acid biosynthesis, transport and lipogenesis. Protein processing in the endoplasmic reticulum was enriched during lactation, likely in support of active milk protein synthesis. Hormone and growth factor signalling and activation of signal transduction pathways, including the JAK-STAT and PPAR pathways, were also differently regulated, indicating key roles for these pathways in functional development of the ovine mammary gland. Changes in the expression of epigenetic regulators, particularly chromatin remodellers, indicate a possible role in coordinating the large-scale transcriptional changes that appear to be required to switch mammary processes from growth and development during late pregnancy to synthesis and secretion of milk during lactation.

Conclusions

Coordinated transcriptional regulation of large numbers of genes is required to switch between mammary tissue establishment during late pregnancy, and activation and maintenance of milk production during lactation. Our findings indicate the remarkable plasticity of the mammary gland, and the coordinated regulation of multiple genes and pathways to begin milk production. Genes and pathways identified by the present study may be important for managing milk production and mammary development, and may inform studies of diseases affecting the mammary gland.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1947-9) contains supplementary material, which is available to authorized users.

Distinct ensembles of medial prefrontal cortex neurons are activated by threatening stimuli that elicit excitation vs. inhibition of movement

Neural circuits controlling defensive behavior were investigated by recording single units in medial prefrontal cortex (mPFC) and dorsolateral periaqueductal gray (dlPAG) while rats expressed conditioned fear responses to an auditory conditioned stimulus (CS; 20-s train of white noise pips) previously paired with an aversive unconditioned stimulus (US; 2-s train of periorbital shocks). The CS elicited conditioned movement inhibition (CMI; characterized by decreased movement speed and freezing) when rats had not recently encountered the US, whereas the CS elicited conditioned movement excitation (CME; characterized by increased movement speed and flight behavior) after recent US encounters. Many mPFC neurons were "strategy-selective" cells that changed their firing rates only when the CS elicited CME (15/71) or CMI (13/71) responses, whereas few mPFC cells (4/71) responded nonselectively to the CS during either response. By contrast, many dlPAG neurons (20/74) responded nonselectively to the CS, but most (40/74) were excited by the CS selectively during CME trials (and none during CMI trials). CME-selective neurons in dlPAG responded phasically after CS pips that elicited CME responses, whereas CME-selective neurons in mPFC showed tonically elevated activity before and after pips that evoked CME responses. These findings suggest that, at the time when the CS occurs, tonic firing rates of CME- and CMI-selective mPFC neurons may bias the rat's choice of whether to express CME vs. CMI responses, perhaps via projections to downstream structures (such as amygdala and PAG) that influence how sensory stimuli are mapped onto motor circuits that drive the expression of competing behaviors.

Maternal insulin sensitivity in midpregnancy does not determine birth weight after embryo transfer between large and small breed sheep

Embryo transfer of large sheep breed embryos (Suffolk) into small breed ewes (Cheviot) constrains birth size, but the maternal factors influencing fetal growth restriction are unknown. We hypothesized that reciprocal embryo transfer crosses between breeds of divergent size would affect pregnancy-related development of maternal insulin resistance in midgestation, thereby influencing fetal growth. Following superovulation, embryos were surgically collected 6 d postmating and transferred to recipients on the same day. Between- and within-breed transfers were performed. Between 60 and 70 d of pregnancy overnight-fasted ewes underwent hyperinsulinemic-euglycemic clamps for assessment of insulin sensitivity. Maternal insulin sensitivity did not vary with transferred lamb breed. Overall, Cheviot ewes tended to have higher fasting glucose (P = 0.068), fasting insulin (P = 0.052), and steady-state glucose (P = 0.065) concentrations than Suffolk ewes at the stage of pregnancy studied. As expected, transferred between-breed Suffolk lambs were born lighter (P = 0.014), and transferred between-breed Cheviot lambs tended to be heavier at birth (P = 0.056) than respective lambs transferred within breed. Midgestation insulin sensitivity does not appear to be a major factor constraining growth of large breed sheep fetus transferred into smaller breed or a factor in releasing constraint in growth of a small breed fetus within a larger breed ewe. However, as embryo size is already different between transferred groups by 19 d, factors other than maternal gestational insulin resistance may determine fetal growth in this embryo transfer paradigm.

Agricultural science in the wild: a social network analysis of farmer knowledge exchange

Responding to demands for transformed farming practices requires new forms of knowledge. Given their scale and complexity, agricultural problems can no longer be solved by linear transfers in which technology developed by specialists passes to farmers by way of extension intermediaries. Recent research on alternative approaches has focused on the innovation systems formed by interactions between heterogeneous actors. Rather than linear transfer, systems theory highlights network facilitation as a specialized function. This paper contributes to our understanding of such facilitation by investigating the networks in which farmers discuss science. We report findings based on the study of a pastoral farming experiment collaboratively undertaken by a group of 17 farmers and five scientists. Analysis of prior contact and alter sharing between the group's members indicates strongly tied and decentralized networks. Farmer knowledge exchanges about the experiment have been investigated using a mix of quantitative and qualitative methods. Network surveys identified who the farmers contacted for knowledge before the study began and who they had talked to about the experiment by 18 months later. Open-ended interviews collected farmer statements about their most valuable contacts and these statements have been thematically analysed. The network analysis shows that farmers talked about the experiment with 192 people, most of whom were fellow farmers. Farmers with densely tied and occupationally homogeneous contacts grew their networks more than did farmers with contacts that are loosely tied and diverse. Thematic analysis reveals three general principles: farmers value knowledge delivered by persons rather than roles, privilege farming experience, and develop knowledge with empiricist rather than rationalist techniques. Taken together, these findings suggest that farmers deliberate about science in intensive and durable networks that have significant implications for theorizing agricultural innovation. The paper thus concludes by considering the findings' significance for current efforts to rethink agricultural extension.

Identification of reference genes for RT-qPCR in ovine mammary tissue during late pregnancy and lactation and in response to maternal nutritional programming

The mammary gland is a complex tissue consisting of multiple cell types which, over the lifetime of an animal, go through repeated cycles of development associated with pregnancy, lactation and involution. The mammary gland is also known to be sensitive to maternal programming by environmental stimuli such as nutrition. The molecular basis of these adaptations is of significant interest, but requires robust methods to measure gene expression. Reverse-transcription quantitative PCR (RT-qPCR) is commonly used to measure gene expression, and is currently the method of choice for validating genome-wide expression studies. RT-qPCR requires the selection of reference genes that are stably expressed over physiological states and treatments. In this study we identify suitable reference genes to normalize RT-qPCR data for the ovine mammary gland in two physiological states; late pregnancy and lactation. Biopsies were collected from offspring of ewes that had been subjected to different nutritional paradigms during pregnancy to examine effects of maternal programming on the mammary gland of the offspring. We evaluated eight candidate reference genes and found that two reference genes (PRPF3 and CUL1) are required for normalising RT-qPCR data from pooled RNA samples, but five reference genes are required for analyzing gene expression in individual animals (SENP2, EIF6, MRPL39, ATP1A1, CUL1). Using these stable reference genes, we showed that TET1, a key regulator of DNA methylation, is responsive to maternal programming and physiological state. The identification of these novel reference genes will be of utility to future studies of gene expression in the ovine mammary gland.

Oscillatory neurocomputing with ring attractors: a network architecture for mapping locations in space onto patterns of neural synchrony

Theories of neural coding seek to explain how states of the world are mapped onto states of the brain. Here, we compare how an animal's location in space can be encoded by two different kinds of brain states: population vectors stored by patterns of neural firing rates, versus synchronization vectors stored by patterns of synchrony among neural oscillators. It has previously been shown that a population code stored by spatially tuned ‘grid cells’ can exhibit desirable properties such as high storage capacity and strong fault tolerance; here it is shown that similar properties are attainable with a synchronization code stored by rhythmically bursting ‘theta cells’ that lack spatial tuning. Simulations of a ring attractor network composed from theta cells suggest how a synchronization code might be implemented using fewer neurons and synapses than a population code with similar storage capacity. It is conjectured that reciprocal connections between grid and theta cells might control phase noise to correct two kinds of errors that can arise in the code: path integration and teleportation errors. Based upon these analyses, it is proposed that a primary function of spatially tuned neurons might be to couple the phases of neural oscillators in a manner that allows them to encode spatial locations as patterns of neural synchrony.

Moderate exercise during pregnancy in Wistar rats alters bone and body composition of the adult offspring in a sex-dependent manner

Exercise during pregnancy may have long-lasting effects on offspring health. Musculoskeletal growth and development, metabolism, and later-life disease risk can all be impacted by the maternal environment during pregnancy. The skeleton influences glucose handling through the actions of the bone-derived hormone osteocalcin. The purpose of this study was to test the effects of moderate maternal exercise during pregnancy on the bone and body composition of the offspring in adult life, and to investigate the role of osteocalcin in these effects. Groups of pregnant Wistar rats either performed bipedal standing exercise to obtain food/water throughout gestation but not lactation, or were fed conventionally. Litters were reduced to 8/dam and pups were raised to maturity under control conditions. Whole body dual-energy x-ray absorptiometry, and ex vivo peripheral quantitative computed tomography scans of the right tibia were performed. At study termination blood and tissue samples were collected. Serum concentrations of fully and undercarboxylated osteocalcin were measured, and the relative expression levels of osteocalcin, insulin receptor, Forkhead box transcription factor O1, and osteotesticular protein tyrosine phosphatase mRNA were quantified. Body mass did not differ between the offspring of exercised and control dams, but the male offspring of exercised dams had a greater % fat and lower % lean than controls (p=0.001 and p=0.0008, respectively). At the mid-tibial diaphysis, offspring of exercised dams had a lower volumetric bone mineral density than controls (p=0.01) and in the male offspring of exercised dams the bone: muscle relationship was fundamentally altered. Serum concentrations of undercarboxylated osteocalcin were significantly greater in the male offspring of exercised dams than in controls (p=0.02); however, the relative expression of the measured genes did not differ between groups. These results suggest that moderate exercise during pregnancy can result in lasting changes to the musculoskeletal system and adiposity in offspring, in a sex-specific manner.