Comparison of the diagnostic yield of 3 and 5 mm laparoscopic liver biopsy forceps in cats.

OBJECTIVE: To determine whether 3 and 5 mm laparoscopic cup biopsy forceps provide samples of equivalent diagnostic quality in cats. STUDY DESIGN: Experimental study. ANIMALS: Twelve colony cats undergoing a concurrent nutrition study. METHODS: Two biopsy forceps (3 and 5 mm) and three biopsy techniques (twist, pull, and twist + pull) were used to collect 68 laparoscopic liver samples. Biopsies were performed consecutively with the 3 and 5 mm biopsy sites adjacent to each other. Data analyzed included the number of portal triads and hepatic lobules, tissue crush and fragmentation, overall sample area (mm2 ), sample weight, and agreement regarding morphologic diagnosis. RESULTS: The 5 mm forceps provided more hepatic lobules, portal triads, and a larger tissue weight and histologic area (mm2 ) (p < .01). The twist and pull techniques provide more hepatic lobules and portal triads compared to the twist + pull technique while the twist + pull technique resulted in greater tissue crush compared to the twist technique (p = .0097). There was good agreement for morphological diagnosis between the 3 and 5 mm samples using the twist + pull technique but not for the twist or pull techniques. CONCLUSION: Liver samples can be safely collected with 3 or 5 mm laparoscopic biopsy forceps and provide sufficient tissue for histopathology analysis in cats, with minimal artifact. The diagnostic accuracy of 3 mm samples remains unknown. CLINICAL SIGNIFICANCE: Although 3 mm laparoscopic cup biopsy forceps provided samples of sufficient diagnostic quality for histopathologic interpretation in cats, further studies are required to assess their diagnostic accuracy.

CATastrophic myths part 1: Common misconceptions about the social behavior of domestic cats and implications for their health, welfare, and management.

Cats are among the most popular pets worldwide, but there are still major gaps in the public's general understanding of their social behaviors and related needs, including for socialization. In addition to these knowledge gaps, people often have negative or ambivalent attitudes about cats, which can directly impact their welfare outcomes. Insufficient attention to the behavioral ecology and development of cat sociality, along with failure to account for their highly variable individual preferences and tolerance for social behaviors can lead them to experience distress that undermines both their welfare and the human-animal bond. As Part 1 of a two-part series addressing common myths about cats, the purpose of this first paper is to review and debunk common misperceptions about the social needs and behaviors of cats, including misunderstandings about their social lives and abilities to bond with humans. We also identify where opportunities exist to improve socialization of cats and to advance research in related areas that might better support their behavior and welfare needs.

CATastrophic myths part 2: Common misconceptions about the environmental, nutritional, and genetic management of domestic cats and their welfare implications.

Despite the cat's popularity as a companion species, many owners and practitioners lack high quality information about important aspects of their behavior and management. Myths, anecdotes, and narratives of cats as 'low maintenance, self-sufficient' animals are pervasive, and the degree to which these may underlie complacency about fully meeting cats' needs is unknown. Several studies suggest that cat welfare and the human-cat bond may benefit from improved education about how to optimize the domestic cat's management and husbandry needs in homes and elsewhere. This paper is the second of a two-part series addressing common myths about cats. The purpose of this paper is to review and debunk common misconceptions about optimal cat care, feeding behavior, genetics, and training. Replacing these misconceptions with scientifically generated information could have a significant impact on the behavioral management of cats, positively influencing their physical health, mental stimulation, and well-being, and reducing stress for both cats and the people caring for them. Areas where further research is required to address ambiguities, and to better meet cats' needs in homes and other environments, are also identified.

Comparative protein quality in black soldier fly larvae meal vs. soybean meal and fish meal using classical protein efficiency ratio (PER) chick growth assay model.

Black soldier fly larvae meal (BSFLM) is a relatively new ingredient that has attracted attention for application in human, farm, and companion animal nutrition. However, there is limited data on protein quality (PQ) of BSFLM. This study compared PQ in BSFLM with soybean meal (SBM) and fishmeal (FM) using the classical protein efficiency ratio (PER) chick growth assay model. A total of 240-male day-old Ross × Ross broiler chicks were allocated to 6 test diets for 10 d test. The corn starch-dextrose based diets were: 5 test diets containing 10% crude protein (CP) from casein (as a standard assay diet), SBM, FM, or BSFLM without or with (BSFLM+) additional essential amino acids (EAA) to match the levels of the SBM diet on digestible basis. A sixth diet was nitrogen-free (NFD), to enable calculation of net protein ratio (NPR). The birds had ad libitum access to feed and water, body weight (BW) and feed intake (FI) were recorded at the beginning and end of the experimental feeding period. Body weight gain (BWG), gain to feed ratio (G:F), crude protein intake (CPI), PER, and NPR were calculated. The analyzed CP (as fed) was 10.1, 12.8, 9.5, 11.7, and 14.9% for casein, SBM, FM, BSFLM, and BSFLM+ diets, respectively. Birds fed BSFLM+ had greater BWG (P < 0.01) than birds fed other diets. Feed intake was greater (P < 0.01) for birds fed BSFLM+ and FM diets than birds fed other diets. Birds fed BSFLM+ ate (P < 0.01) more CP than birds fed other diets. Diets had no (P > 0.05) effects on PER and NPR. In terms of ranking, the PER was 2.44, 2.38, 2.34, 2.28, and 2.10 g BWG/g CPI for BSFLM+, SBM, FM, casein, and BSLM, respectively. Corresponding values for NPR were 2.69, 2.78, 2.70, 2.74, and 2.48 g BWG/g CPI, respectively. In conclusion, the protein quality of BSFLM without or with additional EAA was comparable with FM and SBM.

Circulating direct infusion MS and NMR metabolomic profiles of post-gonadectomy kittens with or without additional dietary choline supplementation.

Choline is beneficial for energy metabolism and growth in various species. Choline may work similarly in kittens at risk of obesity. Direct infusion MS (Di-MS) and NMR spectroscopy were used to investigate the metabolomic signatures of kittens supplemented with or without additional dietary choline for 12 weeks. Fifteen intact male kittens consumed a base diet (3310 mg choline/kg DM) to their daily metabolisable energy requirement (DER) over an 11-week acclimation. Kittens were gonadectomised and assigned, based on body weight, to the base diet (CONTROL, n 7) or the base diet with 300 mg/kgBW0·75 additional choline as choline chloride (CHOLINE, n 8) and offered three times their individual energy requirement divided into three meals. At weeks -1 and 12, fasted blood was sampled and serum analysed for 130 metabolites via Di-MS and fifty-one metabolites via NMR spectroscopy. Changes in fasted metabolites were assessed using a repeated-measures GLIMMIX procedure with time and group as fixed effects, and time as a repeated measure. Metabolites of one-carbon metabolism and lipids increased, and medium-chain acyl carnitines decreased from week -1 to 12 for CHOLINE (P < 0·05), but not CONTROL (P > 0·05). Increases in amino acid, biogenic amine and organic compound concentrations were observed in both groups (P < 0·05). The results suggest impacts of dietary choline at greater intakes than currently recommended on one-carbon metabolism and fatty acid oxidation, and these may promote healthy growth in post-gonadectomy kittens.

A case of tail-biting on a multi-site swine operation in Ontario.

This case study describes a severe tail-biting event on a multi-site swine operation in Ontario and outlines the management strategies implemented in an attempt to control the problem. An established social order was clearly present before the tail-biting event occurred. Over 40% of tail-docked pigs in 3 of 8 grower-finisher barns were severely affected, leading to higher mortality and increased numbers of pigs re-housed in hospital pens. Environmental factors, management practices, and animal health in the barns experiencing the tail-biting event are described, including detection of the mycotoxin deoxynivalenol in corn at > 2 ppm. Changes implemented in response to tail-biting included altering the phase-feeding schedule, adding enrichment devices, and increasing surveillance. The subsequent cohort of pigs was followed through the finisher barns and did not engage in the same severity or prevalence of tail-biting as the previous cohort of pigs which experienced the tail-biting event. Key clinical message: No single factor was identified as the initiating cause for the severe tail-biting event. The subsequent cohort of pigs in 4 barns of the same operation were monitored for tail-biting from entry until market, and the incidence of tail-biting was very low.

Un cas de caudophagie dans une exploitation porcine à sites multiples en Ontario. Cette étude de cas décrit un cas grave de caudophagie dans une exploitation porcine à sites multiples en Ontario et décrit les stratégies de gestion mises en oeuvre pour tenter de limiter le problème. Un ordre social établi était clairement présent avant que l'événement de mordillage de queue ne se produise. Plus de 40 % des porcs à la queue coupée dans trois des huit élevages de type croissance-finition ont été gravement touchés, ce qui a entraîné une mortalité plus élevée et un nombre accru de porcs relogés dans des enclos hospitaliers. Les facteurs environnementaux, les pratiques de gestion et la santé animale dans les porcheries où sévissaient la caudophagie sont décrits, y compris la détection de la mycotoxine désoxynivalénol dans le maïs à > 2 ppm. Les changements mis en oeuvre en réponse à la caudophagie comprenaient la modification du calendrier d'alimentation par phases, l'ajout de dispositifs d'enrichissement et l'augmentation de la surveillance. La cohorte suivante de porcs a été suivie dans les porcheries de finition et n'a pas eu la même gravité ou prévalence de caudophagie que la cohorte précédente de porcs qui ont subi l'événement de caudophagie.Message clinique clé :Aucun facteur unique n'a été identifié comme la cause initiale de l'événement grave de caudophagie. La cohorte suivante de porcs dans quatre porcheries de la même exploitation a été surveillée pour la caudophagie depuis l'entrée jusqu'au marché, et l'incidence de la caudophagie était très faible.(Traduit par Dr Serge Messier).

Effect of Varying Levels of Dietary Tryptophan on Aggression and Abnormal Behavior in Growing Pigs.

Body lesions, resulting from tail-biting and ear-biting, can result in decreased health and welfare in pigs. Tryptophan, an indispensable amino acid, is needed to support protein deposition, and the synthesis of the neurotransmitter serotonin, which is important to mood, sleep-wake and eating patterns and might play a role in aggression and abnormal behavior. Two randomized block design studies were conducted to assess the influence of varying dietary tryptophan levels on aggression and abnormal behavior in 8-week-old pigs. Six diets were formulated which met or exceeded all nutrient requirements yet differed according to the dietary tryptophan content. The first study included control (100% standardized ileal digestible tryptophan), supplemented (175% standardized ileal digestible tryptophan), and supplement-plus (250% standardized ileal digestible tryptophan) experimental diets, while the second study included deficient (80% standardized ileal digestible tryptophan), adequate control (105% standardized ileal digestible tryptophan), and extra-tryptophan (130% standardized ileal digestible tryptophan) experimental diets. Concentrations of plasma tryptophan and large neutral amino acids (tyrosine, isoleucine, leucine, valine, and phenylalanine) were analyzed using ultra-performance liquid chromatography and the tryptophan to large neutral amino acid ratio was calculated. Analysis for time active, lying, and engaging in aggressive interactions was carried out using 10-min scan samples to determine behavioral time budgets of the pigs on different experimental diets. Pigs fed diets with supplemented tryptophan had higher concentrations of both plasma tryptophan and tryptophan to large neutral amino acid ratio compared to the pigs fed the control diet (P < 0.05) in the first study, while no significant differences were detected for plasma tryptophan or the tryptophan to large neutral amino acid ratio in the second study. Diet did not have an effect (P > 0.05) on weight, feed intake or behavior throughout the studies. The results suggest that an increase in dietary tryptophan relative to large neutral amino acids, fed for 29 days, impacts circulating plasma tryptophan and therefore, serotonin concentrations in the pig. Despite an increase in circulating plasma tryptophan in response to an increase in dietary tryptophan in the first study, we failed to see an impact of the dietary treatment on body, tail and ear-biting behavior under the conditions studied.

Dietary choline in gonadectomized kittens improved food intake and body composition but not satiety, serum lipids, or energy expenditure.

Gonadectomy is a major risk factor for feline obesity. The lipotropic effects of choline have demonstrated benefits for growth and carcass composition in livestock. The consumption of supplemental choline on body weight (BW), body composition, lipid metabolism, energy expenditure (EE), and serum satiety hormones were evaluated in 15 gonadectomized male kittens. Kittens were offered a base diet formulated for growth (3310mg choline/kg dry matter [DM]) to daily energy requirements (DER) over an 11-week acclimation. Post-gonadectomy, kittens were assigned to a base diet (CONTROL, n = 7) or choline group (base diet with additional choline at 300mg/kg BW0.75 as a top dress) (CHOLINE, n = 8). For 12-weeks post-neuter, kittens were offered three times their DER over three meals to mimic ad libitum feeding. At week -1 and 12, body composition was assessed using dual energy x-ray absorptiometry (DXA), 24-hour indirect calorimetry was performed for EE and respiratory quotients (RQ), and fasted serum samples were analyzed for lipid compounds and satiety hormones. Daily food intake (FI) and weekly BW were measured. Data was analyzed as a repeated measures of variance (ANCOVA) using the GLIMMIX procedure with time and group as fixed effects. CHOLINE had lower mean daily FI and lower rates of BW accretion (P<0.05) in contrast to CONTROL. All absolute body composition data increased over time for both groups, with lower increases in total tissue mass (P = 0.031) and fat mass (P = 0.005) in CHOLINE. Serum satiety hormones and lipid compounds did not differ (P>0.05) between groups, but both groups experienced a decrease in low-density lipoproteins and increase in high-density lipoproteins (P<0.05). Primary substrate utilization showed lipid use when fasted and use of protein or mixed macronutrients in the fed state. Fed state EE decreased post-gonadectomy (P = 0.004), however, CHOLINE did not affect total EE or RQ. These results suggest that supplemental dietary choline reduces FI, BW, and fat mass and may help to reduce the propensity of weight gain and subsequent obesity in gonadectomized feline populations.

Short communication: the effects of a semi-synthetic diet with inclusion of black soldier fly larvae meal on health parameters of healthy adult cats.

In recent years, black soldier fly larvae meal (Hermetia illucens; BSFLM) has gained attention as a high value alternative protein source that is of great interest to the pet food industry. However, little is known regarding the effects of BSFLM on health parameters in adult cats. Thus, the objective of the current study was to determine the short-term effects of a semi-synthetic diet containing 4.6% inclusion of BSFLM on complete blood count (CBC) and serum biochemistry profile of healthy adult cats. Healthy adult male cats (n = 8; 1.4 yr) were fed the experimental diet for 21 d (experimental period) to maintain BW. Cats were washed in on a commercial diet and blood samples were collected before the start and at the end of the experimental period to measure gross health parameters. Results were analyzed as one-way ANOVA using the GLIMMIX procedure in SAS with cat as a random effect (SAS v. 9.4, The SAS Institute, Cary, NC). Cats lost an average of 5% of their BW (P = 0.0003) due to a concurrent decrease in food intake. A significant increase of alanine aminotransferase, chloride, potassium, sodium, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration was observed on day 21 vs. baseline (P < 0.05). In contrast, albumin, amylase, calcium, cholesterol, eosinophil, lymphocyte, monocyte, mean platelet volume, red blood cells, total protein, total solid proteins, and urea decreased over time (P < 0.05). However, all CBC and serum biochemistry parameters stayed within reference range for adult cats, with exception of glucose and mean corpuscular hemoglobin concentration that were above and below the reference range, respectively. Transient increases in glucose concentrations were likely due to sedation with dexmedetomidine prior to blood collection. The changes observed over time in the aforementioned parameters are likely due to changes in macronutrient composition of the diets offered prior to and during the experimental period (commercial diet vs. semi-synthetic diet, respectively) and cannot be attributed solely to a unique property of BSFLM. In conclusion, cats fed a semi-synthetic diet containing 4% BSFLM inclusion for 21 d remained healthy with no clinically relevant changes in CBC and serum biochemistry parameters. Further research should focus on longer term feeding studies and the ability of BSFLM to support the health and well-being of cats.

Safety of Dietary Camelina Oil Supplementation in Healthy, Adult Dogs.

This study aimed to determine whether camelina oil is safe for use in canine diets, using canola oil and flax oil as controls, as they are similar and generally regarded as safe (GRAS) for canine diets. A total of thirty privately-owned adult dogs of various breeds (17 females; 13 males), with an average age of 7.2 ± 3.1 years (mean ± SD) and a body weight (BW) of 27.4 ± 14.0 kg were used. After a 4-week wash-in period using sunflower oil and kibble, the dogs were blocked by breed, age, and size and were randomly allocated to one of three treatment oils (camelina (CAM), flax (FLX), or canola (OLA)) at a level of 8.2 g oil/100 g total dietary intake. Body condition score (BCS), BW, food intake (FI), and hematological and select biochemical parameters were measured at various timepoints over a 16-week feeding period. All of the data were analyzed with ANOVA using the PROC GLIMMIX of SAS. No biologically significant differences were seen between the treatment groups in terms of BW, BCS, FI, and hematological and biochemical results. Statistically significant differences noted among some serum biochemical results were considered small and were due to normal biological variation. These results support the conclusion that camelina oil is safe for use in canine nutrition.

Tail-Biting in Pigs: A Scoping Review.

Tail-biting is globally recognized as a welfare concern for commercial swine production. Substantial research has been undertaken to identify risk factors and intervention methods to decrease and understand this vice. Tail-biting appears to be multifactorial and has proven difficult to predict and control. The primary objective of the scoping review was to identify and chart all available literature on the risk factors and interventions associated with tail-biting in pigs. A secondary objective was to identify gaps in the literature and identify the relevance for a systematic review. An online literature search of four databases, encompassing English, peer-reviewed and grey literature published from 1 January 1970 to 31 May 2019, was conducted. Relevance screening and charting of included articles were performed by two independent reviewers. A total of 465 citations were returned from the search strategy. Full-text screening was conducted on 118 articles, with 18 being excluded in the final stage. Interventions, possible risk factors, as well as successful and unsuccessful outcomes were important components of the scoping review. The risk factors and interventions pertaining to tail-biting were inconsistent, demonstrating the difficulty of inducing tail-biting in an experimental environment and the need for standardizing terms related to the behavior.

Equations used to develop commercial dog food feeding guidelines and Canadian owner feeding practices in 2018.

Feeding guidelines on commercial dog food packages provide a suggested starting point for food provision for dogs. The equations used to develop commercial dog food feeding guidelines and the owner feeding practices surveyed were examined in this study. The equations used to develop feeding guidelines and the energy density calculation method (Traditional Atwater or Modified Atwater equation) were investigated for 200 dry dog foods sold in Canada. Not all energy densities of products were calculated using the modified Atwater equation, a requirement if claiming compliance with the Association of American Feed Control Officials (AAFCO). Commercial feeding guidelines provide conservative estimates of pet dog energy needs. A survey of dog owners' feeding practices was conducted, with 739 responses analyzed. Respondents generally took appropriate action to manage the weight of their dogs through both exercise and dietary management. Further investigation should explore how owners may be successfully managing their dogs' weight without veterinary supervision.

Équations utilisées pour élaborer des lignes directrices commerciales sur l'alimentation des chiens et les pratiques d'alimentation des propriétaires canadiens en 2018. Les directives d'alimentation sur les emballages commerciaux d'aliments pour chiens fournissent un point de départ suggéré pour l'approvisionnement en nourriture des chiens. Les équations utilisées pour élaborer des lignes directrices commerciales sur l'alimentation des chiens et les pratiques d'alimentation des propriétaires sondées ont été examinées dans cette étude. Les équations utilisées pour élaborer des lignes directrices sur l'alimentation et la méthode de calcul de la densité énergétique (équation Atwater traditionnelle ou Atwater modifiée) ont été étudiées pour 200 aliments secs pour chiens vendus au Canada. Toutes les densités énergétiques des produits n'ont pas été calculées à l'aide de l'équation Atwater modifiée, une exigence si l'on prétend être conforme à l'Association of American Feed Control Officials (AAFCO). Les directives d'alimentation commerciales fournissent des estimations prudentes des besoins énergétiques des chiens de compagnie. Une enquête sur les pratiques alimentaires des propriétaires de chiens a été menée, avec 739 réponses analysées. Les répondants ont généralement pris les mesures appropriées pour gérer le poids de leurs chiens par l'exercice et la gestion de l'alimentation. Une enquête plus approfondie devrait explorer comment les propriétaires peuvent gérer avec succès le poids de leurs chiens sans surveillance vétérinaire.(Traduit par Dr Serge Messier).

Investigating the effects of incremental conditioning and supplemental dietary tryptophan on the voluntary activity and behaviour of mid-distance training sled dogs.

Serotonin is a neurotransmitter synthesized by the amino acid tryptophan, that has the potential to impact the behaviour and activity of dogs. The objective of this study was to assess the effects of supplemental tryptophan and a 12-week incremental training regimen on the voluntary activity and behaviour of client-owned Siberian Huskies. Sixteen dogs were blocked for age, BW and sex and then randomly allocated to either the control or treatment group. Both groups were fed the same dry extruded diet; however, the treatment group were supplemented with tryptophan to achieve a tryptophan: large neutral amino acid ratio of 0.075:1. Once a week, a 5-minute video recording was taken immediately pre- and post- exercise to evaluate dogs' behaviours. Activity monitors were used to record voluntary activity on both training and rest days. Linear regression analysis was used to assess the relationship between training week and time spent performing each behaviour. Additionally, a repeated measure mixed model was used to test differences between diet groups and training week for both behavioural and activity count data. The time spent performing agonistic behaviours prior to exercise was negatively associated with week for treatment dogs (ß = -0.32, 95% CI [-0.55, -0.10], P < 0.05) and no change was observed for control dogs (ß = -0.13, 95% CI [-0.41, 0.15], P > 0.10). Treatment did not have any effect on activity levels (P > 0.10). For all dogs, locomotive behaviours decreased prior to exercise as weeks progressed (P < 0.05), while run day voluntary activity depended on the distance run that day (P < 0.05). These data suggest that sled dogs experience an exercise-induced reduction in voluntary locomotion in response to both single bouts and repetitive bouts of exercise. Additionally, tryptophan supplementation may decrease agonistic behaviours, without having any effect on voluntary activity.

An observational study of pet feeding practices and how these have changed between 2008 and 2018.

BACKGROUND: Pet owners have many feeding options, some may be considered unconventional by veterinary practitioners. Provision of appropriate nutrition is a basic requirement, with adverse health outcomes possible when a pet diet is inadequate. OBJECTIVE: To capture dog and cat feeding practices, with a special focus on countries with large English-speaking populations, and to compare with data published over the previous 10 years. METHODS: An electronic questionnaire was provided for dog and cat owners online. Responses were analysed using descriptive statistics, and comparisons made with data from nine peer-reviewed articles published over the previous 10 years. RESULTS: Responses from 3673 English-speaking dog and cat owners in Australia, Canada, New Zealand, the UK and the USA were included. In previous publications, conventional (commercial, heat-processed) products were the predominant method of feeding. In recent publications, feeding unconventional (raw, homemade, vegetarian) diets appeared more prevalent. In the present study, most (79 per cent dogs, 90 per cent cats) pets were offered conventional food. However a few (13 per cent dogs, 32 per cent cats) pets were fed conventional foods exclusively. Many pets were offered homemade (64 per cent dogs, 46 per cent cats) and/or raw (66 per cent dogs, 53 per cent cats) foods. Different feeding practices were associated with geographical location. CONCLUSION: As an increased risk of nutrient insufficiency and associated conditions have been attributed to unconventional feeding practices, veterinarians must be aware of pet feeding trends and educate clients about the nutritional needs of companion animals.

The Behavioural Effects of Innovative Litter Developed to Attract Cats.

Urination and/or defecation outside a designated location has been reported as the most common behavioural reason for surrendering a cat and comprises approximately 30% of cat intakes to shelters. The objective of this study was to determine whether cats would increase in-box elimination when provided a plant-based litter product with attractant (ATTRACT) compared to the same plant-based litter product without attractant (PLANT). Sixteen cats were split into two equal cohorts based on availability from the shelter and group-housed in an enriched room with eight identical litter boxes arranged in a circular pattern equidistant from each other. Following a two-week room acclimation and transition period from clay litter to PLANT litter, boxes were designated either PLANT or ATTRACT litter, balancing for cats' prior box location preferences. For 14 days following litter allocation, cat behaviours such as sniffing, digging, covering, urinating, and defecating were video recorded for 12 h daily. The cats urinated more often in the ATTRACT litter, suggesting that they preferred the ATTRACT litter for urination more than the PLANT litter (p < 0.05). The most significant differences observed were between genders, with males spending significantly more time sniffing and performing urination behaviours (p < 0.05). These results suggest that litter with an attractant may be more effective in eliciting usage for urination, as compared to a litter without the additive.

The effect of graded concentrations of dietary tryptophan on canine behavior in response to the approach of a familiar or unfamiliar individual.

Tryptophan (Trp) is an indispensable dietary amino acid that supports the modulation of mood and behavior in mammalian species through its role in the serotonergic pathway. This study assessed the behavior patterns of 36 healthy, female adult mixed-breed hound dogs fed a control diet (tryptophan = 0.18% as-fed) or 1 of several experimental diets with graded concentrations of tryptophan (0.05%, 0.1%, and 0.15% of the total diet) supplemented on top of the 0.18% basal level. At baseline, and every 8 weeks throughout the 24-week period, behavioral parameters were evaluated for each dog in response to the approach of an individual familiar to the dogs and another individual who was unfamiliar to the dogs. Differences in behavior scores (activity, P = 0.0197; distance, P = 0.0358; confidence, P < 0.0001; and ear position, P < 0.0001) between the unfamiliar and familiar individuals supported the efficacy of the behavioral ethogram used. No consistent and significant differences in behavior were observed, however, among dogs fed the control diet and those fed an experimental diet with any level of tryptophan supplementation. Future research should consider the tryptophan-to-large-neutral-amino-acid ratio and not just tryptophan concentrations, seek to understand the variation in tryptophan requirements among breeds, and look to utilize additional markers of serotonin status.

Le tryptophane (Trp) est un acide aminé alimentaire indispensable qui supporte la modulation de l'humeur et le comportement chez des espèces animales via son rôle dans le cycle sérotonergique. La présente étude a évalué les patrons de comportement de 36 chiennes adultes en santé de race mélangée de type chien de chasse nourries avec une diète contrôlée (tryptophane = 0,18 %, tel que nourri) ou 1 de plusieurs diètes expérimentales avec des concentrations graduées de tryptophane (0,05 %, 0,1 %, et 0,15 % de la diète totale) ajoutées en plus du niveau de base de 0,18 % de la diète. Au temps 0, et à toutes les 8 semaines pendant la période de 24 semaines de l'étude, les paramètres de comportement furent évalués pour chaque chien en réponse à l'approche d'un individu familier aux chiens et un autre individu qui n'était pas familier aux chiens. Les différences dans les pointages de comportement (activité, P = 0,0197; distance, P = 0,0358; confiance, P < 0,0001; et position des oreilles P < 0,0001) entre l'individu familier et le non-familier supporte l'efficacité de l'éthogramme de comportement utilisé. Aucune différence constante ou significative dans le comportement ne fut observée, toutefois, parmi les chiens nourris la diète témoin et ceux nourris avec une diète expérimentale quelque soit le niveau de Trp ajouté. Des recherches ultérieures devraient considérer le ratio tryptophan/gros acide aminé neutre et pas seulement les concentrations de tryptophane, essayer de comprendre la variation dans les besoins de tryptophane parmi les races, et voir à utiliser des marqueurs additionnels du statut de la sérotonine.(Traduit par Docteur Serge Messier).

Dietary Mannoheptulose Does Not Significantly Alter Daily Energy Expenditure in Adult Labrador Retrievers.

Mannoheptulose (MH), a sugar found in avocados that inhibits glycolysis in vitro, has been preliminarily investigated as a novel food ingredient for dogs. This study aimed to determine the effects of dietary MH, delivered as an extract of un-ripened avocado, on energy expenditure (EE) in healthy adult Labrador Retriever dogs (total of 12 dogs, 26.99 ± 0.634 kg, 4.9 ± 0.2 y). The study was a double-blind, cross-over with each dog receiving both dietary treatments, control (CON) and MH (400 mg/kg of diet; 6 mg/kg BW), in random order. Resting and post-prandial (10 h) EE and respiratory quotient (RQ) were determined by indirect calorimetry (d 42). The following day, body composition was assessed using dual X-ray absorptiometry. Continuous activity monitoring was conducted using an Atical® accelerometer (d 43-47). A vastus lateralis muscle biopsy was obtained prior to the morning meal (d 49) and 4 h after consumption of their meal (d 56) to determine the protein content and phosphorylation of 5' adenosine monophosphate-activated protein kinase (AMPK). Diet did not affect body weight, resting EE or skeletal muscle AMPK phosphorylation. Dogs fed MH had significantly lower post-prandial RQ (p = 0.02) and ratio of fat to lean body mass (p = 0.02). Physical activity during light time periods (but not dark) was lower in dogs fed MH (p < 0.05) during weekends, but not on weekdays. These results suggest that MH affects energy balance of adult dogs, but that these effects are not dose dependent and not due to physical activity.

Dietary Mannoheptulose Increases Fasting Serum Glucagon Like Peptide-1 and Post-Prandial Serum Ghrelin Concentrations in Adult Beagle Dogs.

There is a growing interest in the use of nutraceuticals for weight management in companion animals. The purpose of this study was to determine the effects of mannoheptulose (MH), a sugar in avocados that inhibits glycolysis, on energy metabolism in adult Beagle dogs. The study was a double-blind, randomized controlled trial where dogs were allocated to a control (CON, n = 10, 10.1 ± 0.4 kg) or MH containing diet (168 mg/kg, n = 10, 10.3 ± 0.4 kg). Blood was collected after an overnight fast and 1 h post-feeding (week 12) to determine serum satiety related hormones and biochemistry. Resting and post-prandial energy expenditure and respiratory quotient were determined by indirect calorimetry (weeks 4 and 8). Physical activity was measured using an accelerometer (weeks 3, 7, 11). Body composition was assessed using dual X-ray absorptiometry (week 12). MH significantly (p < 0.05) increased fasting serum glucagon-like peptide-1 and post-prandial serum ghrelin. MH tended (p < 0.1) to increase fasting serum gastric inhibitory peptide and decrease physical activity. Together, these findings suggest that dietary MH has the ability to promote satiation and lowers daily energy expenditure.