Analysis of Electrocardiograms and Behavior in Mice from Pregnancy to Lactation Period.

Changes in the mother-offspring relationship are presumably accompanied by dynamic changes in the autonomic nervous system. Although temporal measurements of autonomic activity have been performed in human mothers and infants, the analysis of long-term changes remains unexplored. Mouse mothers can form social bonds with their pups and have a short period of pregnancy and lactation, which makes them useful for the examination of physiological changes from pregnancy to pup-rearing. Therefore, a telemetry system was used for several weeks to measure the changes in the autonomic nervous system and the behavior of mouse mothers. The current results showed that an electrocardiogram (ECG) could be stably recorded regardless of the movements of mothers and parturition. ECG analysis showed that the heart rate gradually decreased from pregnancy to lactation, and sympathetic activity sharply increased as the pups developed. Furthermore, the simultaneous recording of behavior and ECG in the home cage enabled us to understand the behavior-dependent influences on the ECG, thereby revealing the characteristics of autonomic nervous activity during each behavior. Thus, the present experimental method helps to understand how the physiological characteristics of mothers change from pregnancy through pup rearing, supporting the healthy development of pups.

Intergenerational transmission of maternal behavioral traits in mice: involvement of the gut microbiota.

The matrilineal transmission of maternal behavior has been reported in several species. Studies, primarily on rats, have suggested the importance of postnatal experience and the involvement of epigenetic mechanisms in mediating these transmissions. This study aims to determine whether the matrilineal transmission of maternal behavior occurs in mice and whether the microbiota is involved. We first observed that early weaned (EW) female mice showed lower levels of maternal behavior, particularly licking/grooming (LG) of their own pups, than normally weaned (NW) female mice. This difference in maternal behavioral traits was also observed in the second generation, even though all mice were weaned normally. In the subsequent cross-fostering experiment, the levels of LG were influenced by the nurturing mother but not the biological mother. Finally, we transplanted the fecal microbiota from EW or NW mice into germ-free (GF) mice raising pups. The maternal behaviors that the pups exhibited toward their own offspring after growth were analyzed, and the levels of LG in GF mice colonized with microbiota from EW mice were lower than those in GF mice colonized with microbiota from NW mice. These results clearly indicate that, among maternal behavioral traits, LG is intergenerationally transmitted in mice and suggest that the vertical transmission of microbiota is involved in this process. This study demonstrates the universality of the intergenerational transmission of maternal behavioral traits and provides new insights into the role of microbiota.

Association between Pet Ownership and Obesity: A Systematic Review and Meta-Analysis.

Obesity is a major risk factor for lifestyle-related diseases, including cardiovascular disease, type 2 diabetes, and hypertension. Several studies have investigated the association between pet ownership and obesity, but the findings have been inconsistent. This systematic literature review and meta-analysis assessed the association between pet ownership and obesity. Using PubMed and Scopus, we overviewed the literature published until December 2019 and selected pertinent data for meta-analysis. Two independent reviewers extracted the data. Pooled relative risks (RRs) with 95% confidence intervals (CIs) for obesity were calculated using the random-effects model with inverse-variance weighting. The 21 included articles were cross-sectional studies. Five publications (nine analyses) that reported adjusted RRs for BMI ≥ 25 were included in the meta-analysis. No significant association existed between pet ownership and obesity (pooled RR = 1.038; 95% CI, 0.922-1.167; I2 = 51.8%). After stratification by age group (children vs. adults), no significant association was detected (pooled RR = 0.844; 95% CI, 0.604-1.179; I2 = 64.1% vs. pooled RR = 1.099; 95% CI, 0.997-1.212; I2 = 25.2%). Similarly, no significant association was observed between dog ownership and obesity, indicating no association between pet ownership and obesity. However, no infer causation can be reported because all studies included in this meta-analysis were cross-sectional. Therefore, further prospective studies are needed.

Prevalence of 17 feline behavioral problems and relevant factors of each behavior in Japan.

Undesirable behaviors exhibited by cats are regarded as feline behavioral problems. Like canine behavioral problems, feline behavioral problems are commonly reported by owners. Thus, in order to advise cat owners appropriately, veterinarians, particularly general veterinary practitioners, are encouraged to have sufficient knowledge of these problems. However, in ordinary Japanese homes, only a small number of feline behavioral problems have been investigated in terms of prevalence and relevant factors. Comprehensive survey data may improve understanding of feline behavioral problems. In the present study, we distributed an online survey including general information and questions about 17 feline behaviors which can be problematic for owners, to investigate: (1) the prevalence of feline behavioral problems, (2) the most common behavioral problems, and (3) relevant factors for each behavior. We collected 1,376 valid responses. Among all cats, 75.7% exhibited at least one behavioral problem. "Pica" and "Showing fear while on the examination table" were the most frequently reported behavioral problems. To identify factors related to the expression of each behavior, we conducted multiple logistic regression analyses, with the presence of behaviors as objective variables and cats' general information as explanatory variables. Age, sex, breed, number of cats in the household, and type of residence were each associated with more than one behavior. The present study revealed the prevalence of 17 feline behavioral problems in Japanese homes and relevant factors of each behavior. These findings will help veterinarians understand and address feline behavioral problems.

Endocrine Regulations in Human-Dog Coexistence through Domestication.

Endocrine system regulation is important for the maintenance of homeostasis; it controls hormonal functions in complex physiology and behavior and adaptations to social environments. Evidence indicates that for more than 35 000 years, dogs (Canis familiaris) have been domesticated through living with humans. For example, they have acquired human-like social skills, such as eye gazing and pointing gestures. These unique behaviors are, at least partially, regulated by hormones and are thought to have been genetically altered throughout domestication. Glucocorticoids affect social tolerance, while oxytocin facilitates social coordination and familiarity between individuals. We review historical and recent literature to facilitate an understanding of the roles of glucocorticoid and oxytocin functions in the human-canine coexistence dynamic established during domestication.

Prevalence of 25 canine behavioral problems and relevant factors of each behavior in Japan.

Undesirable behaviors exhibited by dogs are called canine behavioral problems. Behavioral problems are common among dogs kept in ordinary homes; hence, veterinarians need to have sufficient knowledge of these problems, so as to advise owners. Among dogs kept in ordinary Japanese homes, only a few behaviors have been investigated regarding prevalence and relevant factors. To improve understanding of behavioral problems, a comprehensive survey is crucial. In this study, we distributed an online survey including general information and questions about 25 canine behaviors that can become problematic to owners, to investigate (1) the prevalence of behavioral problem, (2) the most common behavioral problems, and (3) the relevant factors of each behavior. We collected 2,050 valid responses. Among all dogs, 86.0% exhibited at least one behavioral problem. "Barking at noises inside the house", "Barking at unfamiliar visitors", and "Pica" were the most frequent behavioral problems. To reveal those factors related to the expression of each behavior, we performed multiple logistic regression analyses, with the presence of behaviors as objective variables and dogs' general information as explanatory variables. Breed, age, the presence of other dogs in the household, sex, neutering status, source of acquisition, and type of residence were associated with 19, 16, 5, 4, 4, 4, and 1 behaviors, respectively. This study revealed the prevalence of 25 canine behavioral problems in Japan and relevant factors of each behavior. Our findings will be useful for veterinarians in advising owners about preventing behavioral problems.

Microsatellite loci analysis for individual identification in Shiba Inu.

Eighteen autosomal microsatellite loci were examined using 275 Shiba Inus in Japan. Eighteen dogs representing eight trios were obtained from four breeders to calculate mutation rates, and 257 dogs kept by owners were collected through veterinary clinics throughout Japan to calculate population genetic parameters and estimate discrimination power. After two loci (INU005 and AHTk253) were excluded, average expected heterozygosity (He), polymorphic information content (PIC) and fixation index (F) were 0.665, 0.623 and 0.046, respectively. The combined power of discrimination over the 16 microsatellite markers was more than 0.9999. Therefore, it is suggested that these 16 microsatellite loci recommended by the International Society for Animal Genetics (ISAG) are applicable for individual identification and parentage testing of domestic Shiba Inu in Japan.

"Reactivity to stimuli" is a temperamental factor contributing to canine aggression.

Canine aggression is one of the most frequent problems in veterinary behavioral medicine, which in severe cases may result in relinquishment or euthanasia. As it is important to reveal underlying factors of aggression for both treatment and prevention, we recently developed a questionnaire on aggression and temperamental traits and found that "reactivity to stimuli" was associated with aggression toward owners, children, strangers, and other dogs of the Shiba Inu breed. In order to examine whether these associations were consistent in other breeds, we asked the owners of insured dogs of Anicom Insurance Inc. to complete our questionnaire. The top 17 contracted breeds were included. The questionnaire consisted of dogs' general information, four items related to aggression toward owners, children, strangers, and other dogs, and 20 other behavioral items. Aggression-related and behavioral items were rated on a five-point frequency scale. Valid responses (n = 5610) from owners of dogs aged 1 through 10 years were collected. Factor analyses on 18 behavioral items (response rate over 95%) extracted five largely consistent factors in 14 breeds: "sociability with humans," "fear of sounds," "chase proneness," "reactivity to stimuli," and "avoidance of aversive events." By stepwise multiple regression analyses, using the Schwartz's Bayesian information criterion (BIC) method with aggression points as objective variables and general information and temperamental factor points as explanatory variables, "reactivity to stimuli," i.e., physical reactivity to sudden movement or sound at home, was shown to be significantly associated with owner-directed aggression in 13 breeds, child-directed aggression in eight breeds, stranger-directed aggression in nine breeds, and dog-directed aggression in five breeds. These results suggest that "reactivity to stimuli" is simultaneously involved in several types of aggression. Therefore, it would be worth taking "reactivity to stimuli" into account in the treatment and prevention of canine aggression.

Molecular epidemiology of canine GM1 gangliosidosis in the Shiba Inu breed in Japan: relationship between regional prevalence and carrier frequency.

BACKGROUND: Canine GM1 gangliosidosis is a fatal disease in the Shiba Inu breed, which is one of the most popular traditional breeds in Japan and is maintained as a standard breed in many countries. Therefore, it is important to control and reduce the prevalence of GM1 gangliosidosis for maintaining the quality of this breed and to ensure supply of healthy dogs to prospective breeders and owners. This molecular epidemiological survey was performed to formulate an effective strategy for the control and prevention of this disease. RESULTS: The survey was carried out among 590 clinically unaffected Shiba Inu dogs from the 8 districts of Japan, and a genotyping test was used to determine nation-wide and regional carrier frequencies. The number and native district of affected dogs identified in 16 years from 1997 to June 2013 were also surveyed retrospectively. Of the 590 dogs examined, 6 dogs (1.02%, 6/590) were carriers: 3 dogs (2.27%, 3/132) from the Kinki district and the other 3 dogs from the Hokkaido, Kanto, and Shikoku districts. The retrospective survey revealed 23 affected dogs, among which, 19 dogs (82.6%) were born within the last 7 years. Of the 23 affected dogs, 12 dogs (52.2%) were from the Kinki district. Pedigree analysis demonstrated that all the affected dogs and carriers with the pedigree information have a close blood relationship. CONCLUSIONS: Our results showed that the current carrier frequency for GM1 gangliosidosis is on the average 1.02% in Japan and rather high in the Kinki district, which may be related to the high prevalence observed over the past 16 years in this region. This observation suggests that carrier dogs are distributed all over Japan; however, kennels in the Kinki district may face an increased risk of GM1 gangliosidosis. Therefore, for effective control and prevention of this disease, it is necessary to examine as many breeding dogs as possible from all regions of Japan, especially from kennels located in areas with high prevalence and carrier frequency.

Analysis of associations between behavioral traits and four types of aggression in Shiba Inu.

Canine aggression is one of the behavioral problems for which veterinary behaviorists are most frequently consulted. Despite this, the classification of canine aggression is controversial, and there are several classification methodologies. While the etiology of canine aggression differs among the types of aggression, the behavioral background underlying aggression is not well understood. Behavior trait-based evaluation of canine aggression would improve the effectiveness and efficiency of managing canine aggression problems. We developed a questionnaire addressing 14 behavioral items and items related to four types of canine aggression (owner-, child-, stranger- and dog-directed aggression) in order to examine the associations between behavioral traits and aggression in Shiba Inu. A total of 400 Shiba Inu owners recruited through dog events (n=134) and veterinary hospitals (n=266) completed the questionnaire. Factor analysis sorted the behavioral items from both the event and clinic samples into four factors: "sociability with humans," "reactivity to stimuli," "chase proneness" and "fear of sounds." While "reactivity to stimuli" correlated significantly positively with all of the four types of aggression (P=0.007 to <0.001), "sociability with humans" correlated significantly negatively with child- and stranger-directed aggression (P<0.001). These results suggest that the behavioral traits involved in canine aggression differ among the types of aggression and that specific behavioral traits are frequently simultaneously involved in several types of aggression.

Naloxone blocks the deterioration of male sexual behavior induced by alarm pheromone in rats.

Previously, we have demonstrated that the alarm pheromone deteriorates sexual behavior in male rats, which was blocked by pretreatment with a corticotrophin-releasing hormone (CRH) antagonist. Studies have shown that an opioid antagonist blocked the deterioration of male sexual behavior following intracerebroventricular administration of CRH. Therefore, possibly, the pheromone effects could also be mediated by the opioid system. In this study, we pretreated rats with naloxone, an opioid receptor antagonist, and examined the following sexual behavior modulations in male rats that were exposed to the alarm pheromone. Naloxone blocked the deterioration of sexual behavior in a dose-dependent manner. On the basis of these data and the results of the previous study, we conclude that the alarm pheromone activates the CRH system, which then activates the opioid system, to deteriorate male sexual behavior.

Association of puppies' behavioral reaction at five months of age assessed by questionnaire with their later 'Distraction' at 15 months of age, an important behavioral trait for guide dog qualification.

Guide dogs help visually impaired persons both physically and psychologically. More than half of all candidate dogs do not qualify, mainly for behavioral reasons. Improved training efficacy is desirable, and earlier prediction of qualification-related traits would be beneficial. In a previous study, we identified 'Distraction', assessed during the training period, as an important behavioral trait for judging the qualification of guide dogs at the Japan Guide Dog Association. As a second step, we aimed to develop an index that can predict during the puppy period. In this study, candidate guide dogs, 5-month-old Labrador retrievers, were assessed by puppy raisers using a newly developed questionnaire that consisted of 20 items. The same dogs were assessed later, at 15 months, by trainers to determine 'Distraction'. In principal components analysis, nine items, including excitability toward strangers, initiative while out for a walk, and exploration, composed the first principal component (PC1). When we compared PC1 points with 'Distraction' points, the two categories were positively correlated (n=110, r(s)=0.31, P=0.0009). Although the accuracy of the questionnaire should be increased, the results of the present study suggest that it may be possible to assess and predict 'Distraction', which is associated with disqualification for guide dogs, early in the puppy-raising period.

Olfactory signals mediate social buffering of conditioned fear responses in male rats.

In social animals, the presence of an affiliative conspecific alleviates acute stress responses, and this is called social buffering. We previously reported that social buffering mitigates the fear responses of male rats to auditory conditioned stimuli that had been paired with foot shocks. Subsequent studies revealed that signals that are perceived by the main olfactory epithelium are important for social buffering. Because olfactory signals are the signal perceived by the main olfactory epithelium, we hypothesized that we could induce the social buffering of conditioned fear responses by presenting olfactory signals that were derived from a conspecific. In order to test this hypothesis, we exposed fear-conditioned subjects to a conditioned stimulus either in a clean test box or in a test box that was odorized by keeping a conspecific in it as an odor donor beforehand. When the subjects were tested in the clean test box, they showed behavioral fear responses and enhanced Fos expression in the paraventricular nucleus. In contrast, the presence of conspecific olfactory signals blocked these fear responses and Fos expression. These results suggested that olfactory signals suppress conditioned fear responses. Fos expression in the posteromedial region of the olfactory peduncle and amygdala suggested that this suppression involves the same neural mechanisms as those of social buffering. Taken together, we concluded that olfactory signals mediate the social buffering of conditioned fear responses.

c-Fos expression during the modulation of sexual behavior by an alarm pheromone.

We previously demonstrated that an alarm pheromone released by male Wistar rats evokes several physiological and behavioral responses in other rats. In addition to these responses, the alarm pheromone increased the number of mounts needed for an ejaculation and decreased the hit rate (number of intromissions/sum of the mounts and intromissions). These effects were blocked by pretreatment by a corticotropin releasing hormone (CRH) receptor antagonist. However, the neural mechanisms underlying the modulation of sexual behavior by this pheromone remain unknown. In this study, we measured c-Fos expression in 22 brain sites in pheromone-exposed male rats 60 min after their first ejaculation. The paraventricular nucleus was double-stained for c-Fos and CRH to determine which neurons were activated by the pheromone. The alarm pheromone increased the number of mounts, decreased the hit rate, and increased the number of cells double-labeled for c-Fos and CRH in the paraventricular nucleus. These results indicate that the alarm pheromone is a stressor. Pheromone-exposed rats also showed significantly increased c-Fos expression in the anterior division medial group, anterior division lateral group, and posterior division of the bed nucleus of the stria terminalis, the anterior part of the medial and the basolateral region of the amygdala, and the nucleus paragigantocellularis. Based on these results and previous findings, we propose that the alarm pheromone modifies sexual behavior by inducing CRH release that indirectly activates the nucleus paragigantocellularis.

Risk factors for canine tail chasing behaviour in Japan.

The aim of this study was to investigate the risk factors for tail chasing behaviour that occurs when a dog spins in tight circles to chase its tail, sometimes biting it. The behaviour is a sign of canine compulsive disorder (CD). A questionnaire about tail chasing behaviour and general information about the animals was used to collect data on seven breeds of pet dogs. The data were gathered at a dog event and at veterinary practices. To determine which variables were associated with tail chasing behaviour, stepwise multiple regression analyses were performed. Regardless of cohort, 'breed' and 'source of acquisition' were significantly associated with tail chasing behaviour. Using a chi-square test, the association between 'source of acquisition' and the behaviour was examined separately in two breeds (Shiba inu and Dachshund) that had the largest number of individuals chasing their tails accompanied by biting and/or growling at them. This factor showed a significant and consistent association across the two breeds. With respect to the risk factors of 'breed' and 'source of acquisition', high percentages of Shiba inu and dogs originating from pet stores were included in the group chasing their tails with biting and/or growling. The results suggest that distinct risk factors exist for tail chasing behaviour and such factors appear to be regulated by both genetics and the environment.

Important behavioral traits for predicting guide dog qualification.

Guide dogs for the blind help blind people physically and mentally in their daily lives. Their qualifications are based on health, working performance and temperament; approximately 70% of dogs that fail to qualify are disqualified for behavioral reasons. In order to achieve early prediction of qualification, it would be essential as the first step to identify important temperament traits for guide dogs. Therefore, we administered a questionnaire consisting of 22 temperament items to experienced trainers to assess candidate dogs at the Japan Guide Dog Association after three months of training, which was at least three months prior to the final success (qualified as a guide dog) or failure (disqualified for behavioral reasons) judgment. Factor analyses of question items stably extracted three factors with high internal consistency, Distraction, Sensitivity and Docility. When we compared factor points between successful dogs and failed dogs, the successful dogs showed significantly and consistently lower Distraction points and higher Docility points. Additionally, Distraction points could predict qualification with 80.6% accuracy and detect 28.2% of the failed dogs that had higher Distraction points than any of the successful dogs. Of the nine question items not included in the three factors, two items (;Aggression' and ;Animal interest') were consistently associated with qualification. These results suggest that Distraction is stably assessable and has the strongest impact on success or failure judgment; therefore, it will be the first target to establish a behavioral test that may lead to early prediction of guide dog qualification.

Sequences of canine glutamate decarboxylase (GAD) 1 and GAD2 genes, and variation of their genetic polymorphisms among five dog breeds.

Glutamate decarboxylase (GAD) is the primary enzyme in the brain that catalyzes the synthesis of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter. There are two isoforms named according to their molecular weights, GAD67 and GAD65, which are encoded by GAD1 and GAD2, respectively. To investigate the association between GAD genes and temperament in domestic dogs, Canis familiaris, we sequenced the full lengths of the coding regions of these genes and identified three single nucleotide polymorphisms (SNPs) in GAD1 and one in GAD2. When comparing genotype and allele frequencies of SNPs among five breeds with different behavioral traits, statistically significant interbreed differences were observed for three SNPs in GAD1. These results suggest that GAD1 SNPs may be useful for behavioral genetic studies in dogs.

Sequences and polymorphisms of the canine monoamine transporter genes SLC6A2, SLC6A3, and SLC6A4 among five dog breeds.

Monoamine transporters have roles to regulate the monoamine concentrations in synaptic clefts in the central nervous system and are the targets of antidepressants and psychostimulants. They include transporters for norepinephrine, dopamine and serotonin, which are encoded by the SLC6A2, SLC6A3, and SLC6A4 genes, respectivily. We sequenced the full lengths of the coding regions of these genes for dogs and identified four single nucleotide polymorphisms (SNPs) in SLC6A2 and four in SLC6A3. One SLC6A3 SNP was non-synonymous and caused an amino acid substitution from threonine to serine. The genotype frequencies of these polymorphisms differed significantly among five breeds with different behavioral traits, suggesting that novel SLC6A2 and SLC6A3 SNPs would provide additional useful information for behavioral genetic studies in dogs.

Urinary transforming growth factor-beta1 in feline chronic renal failure.

Transforming growth factor-beta1 (TGF-beta1), an inflammatory cytokine, plays a role in tissue fibrosis, such as glomerular sclerosis and tubulointerstitial fibrosis of the kidneys. In the present study, the urinary TGF-beta1 level of cats diagnosed with chronic renal failure (CRF) was measured to investigate its relationship to the pathogenesis of feline CRF. Urinary TGF-beta1 levels (TGF-beta1/creatinine ratio) were significantly increased compared with healthy controls, whereas serum levels of TGF-beta1 were not. These results indicate that TGF-beta1 is expressed in the kidneys of CRF cats, and that it was reflected in the urinary TGF-beta1 level. Therefore, TGF-beta1 may play a role in feline CRF, and urinary TGF-beta1 could be used as a clinical marker for renal fibrosis.