The Function of Probiotics and Prebiotics on Canine Intestinal Health and Their Evaluation Criteria.

Maintaining homeostasis within the intestinal microbiota is imperative for assessing the health status of hosts, and dysbiosis within the intestinal microbiota is closely associated with canine intestinal diseases. In recent decades, the modulation of canine intestinal health through probiotics and prebiotics has emerged as a prominent area of investigation. Evidence indicates that probiotics and prebiotics play pivotal roles in regulating intestinal health by modulating the intestinal microbiota, fortifying the epithelial barrier, and enhancing intestinal immunity. This review consolidates literature on using probiotics and prebiotics for regulating microbiota homeostasis in canines, thereby furnishing references for prospective studies and formulating evaluation criteria.

Protective effect of chicken yolk antibody Y against Campylobacter jejuni induced diarrhea in cats.

Campylobacter jejuni (C. jejuni) is a common pathogen that often causes diarrhea, loss of appetite, and even enteritis in domestic cats, affecting their growth and development, especially in kittens under 6 months of age. Oral passive immunization with chicken yolk antibody Y has been proved effective for the treatment of gastrointestinal pathogen infections due to its high specificity. In this study, C. jejuni was isolated from diarrheal cat feces, and the specific egg yolk antibody Y against C. jejuni was demonstrated to effectively inhibit its proliferation in vitro experiments. To evaluate the effect of anti-C. jejuni IgY, the mouse C. jejuni infection model was established and it was found that IgY could alleviate C. jejuni-induced clinical symptoms. Consistent with these results, the reduction of pro-inflammatory factors and intestinal colonization by C. jejuni in the IgY-treated groups, especially in the high dose group. We then evaluated the protective effect of IgY on young Ragdoll cats infected with C. jejuni. This specific antibody reduced the rate of feline diarrhea, protected the growth of young cats, inhibited systemic inflammatory hyperactivation, and increased fecal short-chain fatty acid concentrations. Notably, IgY may have a protective role by changing intestinal amino acid metabolism and affecting C. jejuni chemotaxis. Collectively, specific IgY is a promising therapeutic strategy for C. jejuni-induced cat diarrhea.

Exploring the effects of lysozyme dietary supplementation on laying hens: performance, egg quality, and immune response.

An experiment was conducted to evaluate the dietary supplementation with lysozyme's impacts on laying performance, egg quality, biochemical analysis, body immunity, and intestinal morphology. A total of 720 Jingfen No. 1 laying hens (53 weeks old) were randomly assigned into five groups, with six replicates in each group and 24 hens per replicate. The basal diet was administered to the laying hens in the control group, and it was supplemented with 100, 200, 300, or 400 mg/kg of lysozyme (purity of 10% and an enzyme activity of 3,110 U/mg) for other groups. The preliminary observation of the laying rate lasted for 4 weeks, and the experimental period lasted for 8 weeks. The findings demonstrated that lysozyme might enhance production performance by lowering the rate of sand-shelled eggs (P < 0.05), particularly 200 and 300 mg/kg compared with the control group. Lysozyme did not show any negative effect on egg quality or the health of laying hens (P > 0.05). Lysozyme administration in the diet could improve intestinal morphology, immune efficiency, and nutritional digestibility in laying hens when compared with the control group (P < 0.05). These observations showed that lysozyme is safe to use as a feed supplement for the production of laying hens. Dietary supplementation with 200 to 300 mg/kg lysozyme should be suggested to farmers as a proper level of feed additive in laying hens breeding.

Effects of species-relevant auditory stimuli on stress in cats exposed to novel environment.

Environmental changes like vet visit could cause stress in cats. Studies have attempted to develop stress management strategies targeting sensory systems. Even though species-appropriate music which includes cat affiliative sound (e.g., cats' purring and suckling sound) has been shown to relieve stress in cats. Little is known whether the cat sound alone works in stress management. This study was conducted to investigate the effects of species-relevant auditory stimuli on stress in cats exposed to a novel environment. During the 28-day experiment periods, 20 cats received four types of sound treatments which included silence (T1), purr of cats (T2), eating sound in cats (T3), and the mixed sound of T2 and T3 (T4) in a novel environment in random orders with intervals of 1 week between treatments. Cats' behaviors were recorded during each 10-min test. Results showed that T4 reduced visual scanning (P = 0.017) without significantly affecting other behaviors, compared with other treatments. Together, the two types of cat-specific sounds did not exert pronounced effects of relieving stress on cats exposed to a novel environment.

Changes in gut microbiota and short-chain fatty acids are involved in the process of canine obesity after neutering.

Neutering is a significant risk factor for obesity in dogs. Changes in gut microbiota and its metabolites have been identified as a key player during obesity progression. However, the mechanisms that promote neuter-associated weight gain are not well understood. Therefore, in this study, sixteen clinically healthy Beagle dogs (6 male and 10 female, mean age = 8.22 ±â€…0.25 mo old) were neutered. Body weight (BW) and body condition score (BCS) were recorded at 1 d before neutering, 3, 6, 10, 16, and 21 mo after neutering. Dogs were grouped based on their BCS as ideal weight group (IW, n = 4, mean BW = 13.22 ±â€…1.30 kg, mean BCS = 5.00 ±â€…0.41) and obese group (OB, n = 12, mean BW = 18.57 ±â€…1.08 kg, mean BCS = 7.92 ±â€…0.82) at 21 mo after neutering. Serum lipid profile, glucose, and hormones and fecal microbiota and short-chain fatty acids (SCFAs) were measured. Our results showed that OB dogs had greater (P < 0.0001) BW (18.57 vs. 13.22 kg), BCS (7.92 vs. 5.00), and average daily gain (12.27 vs. 5.69 g/d) than IW dogs at 21 mo after neutering, and the obesity rate was up to 60%. In addition, significant increases (P < 0.05) in serum triglyceride (TG, 1.10 vs. 0.56 mmol/L) and high-density lipoprotein cholesterol (HDL-C, 6.96 vs. 5.40 mmol/L) levels and a significant decrease (P < 0.05) in serum adiponectin (APN, 54.06 vs. 58.39 µg/L) level were observed in OB dogs; serum total cholesterol (4.83 vs. 3.75 mmol/L) (P = 0.075) and leptin (LEP, 2.82 vs. 2.53 µg/L) (P = 0.065) levels tended to be greater in OB dogs; there was a trend towards a lower (P = 0.092) APN/LEP (19.32 vs. 21.81) in OB dogs. Results of fecal microbial alpha-diversity showed that Observed_species and Chao1 indices tended to be lower (P = 0.069) in OB dogs. The STAMP and LEfSe analyses revealed that OB dogs had a greater (P < 0.05 and LDA > 2) reduction in relative abundances of Bacteroides, Prevotella_9, and Megamonas than IW dogs. In addition, OB dogs also had greater (P < 0.05) reduction in fecal acetate, propionate, and butyrate concentrations than IW dogs. Moreover, clear negative correlations (|r| > 0.5 and P < 0.05) were found between SCFAs-producing bacteria and BW, TG, and HDL-C. The functional predictions of microbial communities based on PICRUSt2 analysis revealed that lipid metabolism and endocrine system were significantly disturbed in obese dogs after neutering. Thus, intervention with SCFAs-producing bacteria might represent a new target for the prevention or treatment of canine obesity after neutering. Moreover, weight control before neutering may also contribute to the prevention of canine obesity after neutering.

Neutering contributes to canine obesity risk. In this study, obesity rate of 60% at 21 mo after neutering was observed. Obese dogs had greater serum triglyceride, total cholesterol, high-density lipoprotein cholesterol, and leptin levels and lower adiponectin level than ideal weight dogs. In addition, fecal microbiota analysis found a decreasing microbial diversity in obese dogs, and decreasing SCFAs-producing bacteria Megamonas, Bacteroides, and Prevotella_9 in obese dogs resulted in lower production of fecal acetate, propionate, and butyrate. Importantly, strong negative correlations between SCFAs-producing bacteria and body weight, TG, and HDL-C revealed that SCFAs-producing bacteria are involved in the process of canine obesity after neutering. Thus, intervention with SCFAs-producing bacteria may be a target for the prevention or treatment of canine obesity after neutering. Moreover, weight control before neutering may also contribute to the prevention of canine obesity after neutering.

Tissue accumulation of polystyrene microplastics causes oxidative stress, hepatopancreatic injury and metabolome alterations in Litopenaeus vannamei.

Microplastics (MPs) pose one of the major environmental threats to marine organisms and ecosystems on a global scale. Although many marine crustaceans are highly susceptible to MPs pollution, the toxicological effects and mechanisms of MPs on crustaceans are poorly understood. The current study focused on the impacts of MPs accumulation in shrimp Litopenaeus vannamei at the behavioral, histological and biochemical levels. The results demonstrated the accumulation of polystyrene MPs in various organs of L. vannamei, with highest MPs abundance in the hepatopancreas. The MPs accumulated in shrimp caused growth inhibition, abnormal swimming behavior and reduced swimming performance of L. vannamei. Following MPs exposure, oxidative stress and lipid peroxidation were also observed, which were strongly linked to attenuated swimming activity of L. vannamei. The above MPs-induced disruption in balance of antioxidant system triggered the hepatopancreatic damage in L. vannamei, which was exacerbated with increasing MPs concentrations (from 0.02 to 1 mg L-1). Furthermore, metabolomics revealed that MPs exposure resulted in alterations of metabolic profiles and disturbed glycolysis, lipolysis and amino acid metabolism pathways in hepatopancreas of L. vannamei. This work confirms and expands the knowledge on the sublethal impacts and toxic modes of action of MPs in L. vannamei.

Abrupt Dietary Change and Gradual Dietary Transition Impact Diarrheal Symptoms, Fecal Fermentation Characteristics, Microbiota, and Metabolic Profile in Healthy Puppies.

Dietary changes are inevitable for pets, yet little is known about the impact of different dietary change methods on the gastrointestinal response. The current comparative study evaluated the effects of different dietary changes on the diarrheal symptoms, fecal fermentation characteristics, microbiota, and metabolic profile of healthy puppies. A total of 13 beagle puppies were randomly divided into two groups; puppies in the abrupt change (AC) group were given 260 g of a chicken- and duck-based extruded diet (CD)daily for the one-week transition period, whereas puppies in the gradual transition (GT) group were fed according to a gradual transition ratio of a salmon-based extruded diet (SA) and a CD diets with a difference of 40 g per day for seven consecutive days. Serum samples were collected on D7, and fecal samples were collected on D0 and D7. The results indicated that GT reduced the incidence of diarrhea in puppies throughout the trial period. Dietary change methods had no influence on serum inflammatory factors or fecal SCFAs, but isovaleric acid was significantly reduced after GT. Meanwhile, 16S rRNA sequencing showed that the fecal microbiota was changed after different dietary changes. Compared with the bacterial changes after AC, the relative abundances of beneficial bacteria (i.e., Turicibacter and Faecalibacterium) in feces were increased after GT in puppies. Additionally, both GT and AC caused changes in amino acid metabolism, while AC also altered lipid metabolism. AC increased fecal histamine and spermine concentrations, but decreased concentrations of metabolites such as 5-hydroxyindoleacetic acid and serotonin. Our findings indicated that GT most likely reduced the diarrhea rate in puppies by modulating the composition and metabolism of the gut microbiota.

Antimicrobial Peptides Relieve Transportation Stress in Ragdoll Cats by Regulating the Gut Microbiota.

Transportation is common in cats and often causes stress and intestinal disorders. Antimicrobial peptides (AMPs) exhibit a broad spectrum of antibacterial activity, and they may have the capacity for antioxidant and immune regulation. The objective of this study was to investigate the effects of dietary supplementation with AMPs on stress response, gut microbiota and metabolites of cats that have undergone transport stress. A total of 14 Ragdoll cats were randomly allocated into 2 treatments: basal diet (CON) and a basal diet supplemented with 0.3% AMPs. After a 6-week feeding period, all cats were transported for 3 h and, then, fed for another week. The results show that the diarrhea rate of cats was markedly reduced by supplementation with AMPs throughout the trial period (p < 0.05). In addition, AMPs significantly reduced serum cortisol and serum amyloid A (p < 0.05) and increased apolipoprotein 1 after transportation (p < 0.05). Moreover, AMPs reduced the level of inflammatory factors in the serum caused by transportation stress, including tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1ß) (p < 0.05). The AMPs enhanced the activities of glutathione peroxidase (p < 0.01) and superoxide dismutase (p < 0.05). Furthermore, cats fed AMPs had higher levels of branched chain fatty acids (BCFAs) and a relative abundance of Blautia and a lower relative abundance of Negativibacillus after transportation (p < 0.05). The serum metabolome analysis further revealed that AMPs markedly regulated lipid metabolism by upregulating cholic acid expression. In conclusion, AMP supplementation alleviated oxidative stress and inflammatory response in transportation by regulating the gut microbiota and metabolites, thereby relieving stress-induced diarrhea and supporting gut and host health in cats.

Dietary Strategies for Relieving Stress in Pet Dogs and Cats.

A variety of physical, emotional, and mental factors can induce a stress response in pet dogs and cats. During this process, hypothalamus-pituitary-adrenal (HPA) and sympathetic-adrenal medulla (SAM) axes are activated to produce a series of adaptive short-term reactions to the aversive situations. Meanwhile, oxidative stress is induced where there is an imbalance between the production and scavenging of reactive oxygen species (ROS). Oxidative damage is also incorporated in sustained stress response causing a series of chronic problems, such as cardiovascular and gastrointestinal diseases, immune dysfunction, and development of abnormal behaviors. In this review, the effects and mechanisms of dietary regulation strategies (e.g., antioxidants, anxiolytic agents, and probiotics) on relieving stress in pet dogs and cats are summarized and discussed. We aim to shed light on future studies in the field of pet food and nutrition.

Wet-food diet promotes the recovery from surgery of castration and control of body weight in adult young cats.

Inappropriate dietary management may lead to delayed recovery from castration surgery and significant weight gain in cats after castration. Wet canned food often exhibits more advantageous characteristics than dry food (e.g., higher palatability and digestibility, and lower energy density). This study compared the effects of canned and dry food on surgical recovery and weight management in cats after castration. Eighteen healthy cats (weighed 4.33 ± 1.04 kg and aged 18-months old) were allocated to one of the two dietary treatments (N = 9/group), dry (CON) and canned food (CAN) balanced for sex and initial BW. Cats were fed ad libitum for 7 weeks, including one week before surgery (week 0) and 6 weeks after surgery (week 1-6). Daily dry matter intake (DMI), and weekly body weight (BW) and body condition score (BCS) was obtained. Feces were collected for measuring nutrient digestibility and concentrations of short-chain fatty acids (SCFA) and branched-chain fatty acids (BCFA). Physical pain and wound surface assessment were performed at week 1. Blood was also collected intermittently for measuring biochemical indices and untargeted metabolomics analysis. Results indicated that BW, BCS and daily DMI in CON group increased (P < 0.05) over time after castration, but were maintained relatively stable in CAN group. Cats in CAN group exhibited less pain-related behavior as reflected by lower score of comfort (P < 0.05) and vocalization (P < 0.10), improved wound surface assessment (P < 0.10), lower level of lipase (P < 0.10) and ratio of blood urea nitrogen/serum creatinine (BUN/SC; P < 0.05), and higher level of superoxide dismutase (SOD; P < 0.05) in week 1 than CON cats. Meanwhile, the CAN group had significantly higher concentration of immunoglobulin G (IgG) on days 5 and 7, and higher level of high-density lipoprotein cholesterol (HDL-C; P < 0.10) but lower triglyceride (TG; P < 0.05) than CON group on day 20 and 48. Fecal total and most individual SCFA increased significantly from week 1 to week 6 regardless of diet, but the increase of butyric acid over time only occurred in CON group (P < 0.05). Also, serum metabolomic analysis revealed differential metabolic pathways between the two groups. Overall, compared with the dry food, the canned food tested in our study promoted cat wound recovery by reducing pain and increasing immune and antioxidative capacity after sterilizing surgery, and helped to maintain healthy body condition in cats after castration.

Castration is a surgical operation common in pet cats and dogs, and weight gain is often observed a period after castration. Nutritional management can be important for animal health in both processes. Due to differences in manufacturing techniques and nutrient composition, wet canned food generally exhibits higher palatability and lower energy density than dry food. Till date, few studies have explored if compared to dry kibbles, canned diet can have advantages in promoting recovery from castration surgery and maintaining normal body condition after castration in cats. In our study, dry and canned diets were fed to cats experiencing castration surgery with a free-feeding method. During the one week after surgery, cats fed canned food exhibited less pain and discomfort, and improved inflammation and antioxidative capacity than cats fed dry food. During the four weeks after surgery, cats fed dry food showed significantly more weight gain and change of body condition, meanwhile their blood and fecal measures resembled more of those observed in overweight and/or obese individuals than cats fed canned food. Collectively, canned food with high palatability and low energy density promoted the recovery of cats from the castration surgery and reduced their weight gain after castration.

Effects of black soldier fly larvae as protein or fat sources on apparent nutrient digestibility, fecal microbiota, and metabolic profiles in beagle dogs.

Black soldier fly (Hermetia illucens) larvae (BSFL) act as a biological system converting organic waste into protein and fat with great potential application as pet food. To evaluate the feasibility of BSFL as a protein and fat source, 20 healthy beagle dogs were fed three dietary treatments for 65 days, including (1) a basal diet group (CON group), (2) a basal diet that replaced 20% chicken meal with defatted black soldier fly larvae protein group (DBP group), and (3) a basal diet that replaced 8% mixed oil with black soldier fly larvae fat group (BF group). This study demonstrated that the serum biochemical parameters among the three groups were within the normal range. No difference (p > 0.05) was observed in body weight, body condition score, or antioxidant capacity among the three groups. The mean IFN-γ level in the BF group was lower than that in the CON group, but there was no significant difference (p > 0.05). Compared with the CON group, the DBP group had decreasing (p < 0.05) apparent crude protein and organic matter digestibility. Furthermore, the DBP group had decreasing (p < 0.05) fecal propionate, butyrate, total short-chain fatty acids (SCFAs), isobutyrate, isovalerate, and total branched-chain fatty acids (BCFAs) and increased (p < 0.05) fecal pH. Nevertheless, there was no difference (p > 0.05) in SCFAs or BCFAs between the CON and BF groups. The fecal microbiota revealed that Lachnoclostridium, Clostridioides, Blautia, and Enterococcus were significantly enriched in the DBP group, and Terrisporobacter and Ralstonia were significantly enriched in the BF group. The fecal metabolome showed that the DBP group significantly influenced 18 metabolic pathways. Integrating biological and statistical correlation analysis on differential fecal microbiota and metabolites between the CON and DBP groups found that Lachnoclostridium, Clostridioides, and Enterococcus were positively associated with biotin. In addition, Lachnoclostridium, Clostridioides, Blautia, and Enterococcus were positively associated with niacinamide, phenylalanine acid, fumaric acid, and citrulline and negatively associated with cadavrine, putrescine, saccharopine, and butyrate. In all, 20% DBP restrained the apparent CP and OM digestibility, thereby affecting hindgut microbial metabolism. In contrast, 8% BF in the dog diet showed no adverse effects on body condition, apparent nutrient digestibility, fecal microbiota, or metabolic profiles. Our findings are conducive to opening a new avenue for the exploitation of DBP and BF as protein and fat resources in dog food.

Effects of Softening Dry Food with Water on Stress Response, Intestinal Microbiome, and Metabolic Profile in Beagle Dogs.

Softening dry food with water is believed to be more beneficial to the intestinal health and nutrients absorption of dogs by some owners, but there appears to be little scientific basis for this belief. Thus, this study aimed to compare feeding dry food (DF) and water-softened dry food (SDF) on stress response, intestinal microbiome, and metabolic profile in dogs. Twenty healthy 5-month-old beagle dogs were selected and divided into two groups according to their gender and body weight using a completely randomized block design. Both groups were fed the same basal diet, with one group fed DF and the other fed SDF. The trial lasted for 21 days. The apparent total tract digestibility (ATTD) of nutrients, inflammatory cytokines, stress hormones, heat shock protein-70 (HSP-70), fecal microbiota, short-chain fatty acids (SCFAs), branch-chain fatty acids (BCFAs), and metabolomics were measured. Results showed that there was no significant difference in body weight, ATTD, and SCFAs between the DF and SDF groups (p > 0.05), whereas feeding with SDF caused a significant increase in serum cortisol level (p < 0.05) and tended to have higher interleukin-2 (p = 0.062) and HSP-70 (p = 0.097) levels. Fecal 16S rRNA gene sequencing found that the SDF group had higher alpha diversity indices (p < 0.05). Furthermore, the SDF group had higher levels of Streptococcus, Enterococcus, and Escherichia_Shigella, and lower levels of Faecalibacterium (p < 0.05). Serum and fecal metabolomics further showed that feeding with SDF significantly influenced the purine metabolism, riboflavin metabolism, and arginine and proline metabolism (p < 0.05). Overall, feeding with SDF caused higher cortisol level and generated effects of higher intestinal microbial diversity in dogs, but it caused an increase in some pathogenic bacteria, which may result in intestinal microbiome disturbance and metabolic disorder in dogs. In conclusion, feeding with SDF did not provide digestive benefits but caused some stress and posed a potential threat to the intestinal health of dogs. Thus, SDF is not recommended in the feeding of dogs.

Fecal microbiota and metabolomics revealed the effect of long-term consumption of gallic acid on canine lipid metabolism and gut health.

Gallic acid (GA) is a natural polyphenolic compound with many health benefits. To assess the potential risk of long-term consumption of GA to gut health, healthy dogs were fed a basal diet supplemented with GA (0%, 0.02%, 0.04%, and 0.08%) for 45 d, and fecal microbiota and metabolomics were evaluated. This study demonstrated that GA supplementation regulated serum lipid metabolism by reducing serum triglyceride, fat digestibility, and Bacteroidetes/Firmicutes ratio. In addition, the relative abundance of Parasutterella was significantly lower, and the SCFAs-producing bacteria were increased along with fecal acetate and total SCFAs contents accumulation in the 0.08% GA group. Metabolomics data further elucidated that 0.08% GA significantly affected carbohydrate metabolism by downregulating succinic acid in fece, thereby alleviating inflammation and oxidative stress. Overall, this study confirmed the beneficial effects of long-term consumption of GA on lipid metabolism and gut health, and the optimal level of GA supplementation was 0.08%.

Characterizing the influence of gut microbiota on host tryptophan metabolism with germ-free pigs.

Intestinal microbes are closely associated with host health, depending on metabolic crosstalk between the microbiota and host. Tryptophan metabolism is one of the best examples of metabolic crosstalk between intestinal microbiota and host; however, our understanding about the influence of intestinal microbiota on host tryptophan metabolism is limited. Thus, we established germ-free (GF) pig models to systemically explore the influence of intestinal microbiota on tryptophan metabolism. Five GF pigs were kept in GF conditions throughout the experiment (GF group). Six GF pigs were transplanted with fecal microbiota from donor sows to act as control pigs. Compared with control pigs, the GF pigs had remarkable alterations in tryptophan metabolism. The differential metabolites (P < 0.05) were mainly found in the liver, circulation system and large intestine. Notably, the alteration of metabolites in tryptophan metabolism varied among organs, especially for the serotonin pathway. In GF pigs, tryptophan and kynurenine in the large intestine and 5-hydroxytryptophan in most organs were increased (P < 0.05), while metabolites in the indole pathway in most organs were decreased (P < 0.05). Collectively, our study reveals changes in tryptophan metabolism in GF pigs, highlighting the critical role of gut microbes in shaping host tryptophan metabolism.

Dealing With Stress in Cats: What Is New About the Olfactory Strategy?

Domestic cats are descended from solitary wild species and rely heavily on the olfaction system and chemical signals for daily activities. Cats kept as companion animals may experience stress due to a lack of predictability in their physical or social environment. The olfactory system is intimately connected to the brain regions controlling stress response, thus providing unique opportunities for olfactory strategies to modify stress and related behavioral problems in cats. However, the olfactory intervention of stress in cats has been mainly focused on several analog chemical signals and studies often provide inconsistent and non-replicable results. Supportive evidence in the literature for the potentially effective olfactory stimuli (e.g., cheek and mammary gland secretions, and plant attractants) in treating stress in cats was reviewed. Limitations with some of the work and critical considerations from studies with natural or negative results were discussed as well. Current findings sometimes constitute weak evidence of a reproducible effect of cat odor therapy for stress. The welfare application of an olfactory stimulus in stress alleviation requires a better understanding of its biological function in cats and the mechanisms at play, which may be achieved in future studies through methodological improvement (e.g., experiment pre-registration and appropriate control setting) and in-depth investigation with modern techniques that integrate multisource data. Contributions from individual and environmental differences should be considered for the stress response of a single cat and its sensitivity to olfactory manipulation. Olfactory strategies customized for specific contexts and individual cats can be more effective in improving the welfare of cats in various stressful conditions.

Effect of Dietary Methylsulfonylmethane Supplementation on Growth Performance, Hair Quality, Fecal Microbiota, and Metabolome in Ragdoll Kittens.

Methylsulfonylmethane (MSM) is a natural sulfur-containing organic substance that has many biological functions, such as antioxidant, anti-inflammatory, skin nourishing, and hair growth-promoting effects. This study was conducted to determine the effect of MSM supplementation on growth performance, antioxidant capacity, and hair quality in kittens. A total of 21 Ragdoll kittens were assigned to three diets by initial body weight and gender: basal diet supplemented with 0%, 0.2%, and 0.4% MSM (CON, LMSM, and HMSM groups) for 65 days. During the whole period, the food intake of kittens in the MSM-treated groups tended to be higher (P < 0.10) compared with the CON group, and the average daily gain (ADG) had no significant difference when compared to the kittens in the CON group (P > 0.05). Antioxidant capacity had no significant difference (P > 0.05) among the groups. The scale thickness of hair tended to be smaller in the LMSM group compared to the CON group (P < 0.10) and decreased significantly (P < 0.05) over time from d 0 to d 65 in the LMSM group, indicating the improvement of hair quality. Besides, supplementation with LMSM increased bacterial diversity. Kittens fed MSM had no significant differences in fecal genus at the end of the study. No significant differences in fecal short-chain fatty acids were observed among groups. Fecal metabolomics analysis further revealed that MSM hardly affected the metabolites. Overall, dietary supplementation with 0.2% MSM can improve the hair quality of kittens. Furthermore, 0.2∼0.4% of MSM had no detrimental effects on serum biochemistry, growth performance, gut microbiota, and metabolome, which supports the safety inclusion of MSM to a certain degree in feline diets. To the best of our knowledge, this is the first study to investigate the effects of MSM supplementation in cats.

Gallnut Tannic Acid Exerts Anti-stress Effects on Stress-Induced Inflammatory Response, Dysbiotic Gut Microbiota, and Alterations of Serum Metabolic Profile in Beagle Dogs.

Stress exposure is a potential threat to humans who live or work in extreme environments, often leading to oxidative stress, inflammatory response, intestinal dysbiosis, and metabolic disorders. Gallnut tannic acid (TA), a naturally occurring polyphenolic compound, has become a compelling source due to its favorable anti-diarrheal, anti-oxidative, anti-inflammatory, and anti-microbial activities. Thus, this study aimed to evaluate the anti-stress effects of gallnut TA on the stress-induced inflammatory response, dysbiotic gut microbiota, and alterations of serum metabolic profile using beagle models. A total of 13 beagle dogs were randomly divided into the stress (ST) and ST + TA groups. Dietary supplementation with TA at 2.5 g/kg was individually fed to each dog in the ST + TA group for 14 consecutive days. On day 7, all dogs were transported for 3 h from a stressful environment (days 1-7) to a livable site (days 8-14). In our results, TA relieved environmental stress-induced diarrheal symptoms in dogs and were shown to protect from myocardial injury and help improve immunity by serum biochemistry and hematology analysis. Also, TA inhibited the secretion of serum hormones [cortisol (COR), glucocorticoid (GC), and adrenocorticotropic hormone (ACTH)] and the expression of heat shock protein (HSP) 70 to protect dogs from stress-induced injury, thereby relieving oxidative stress and inflammatory response. Fecal 16S rRNA gene sequencing revealed that TA stimulated the growth of beneficial bacteria (Allobaculum, Dubosiella, Coriobacteriaceae_UCG-002, and Faecalibaculum) and suppressed the growth of pathogenic bacteria (Escherichia-Shigella and Streptococcus), thereby increasing fecal butyrate levels. Serum metabolomics further showed that phytosphingosine, indoleacetic acid, arachidonic acid, and biotin, related to the metabolism of sphingolipid, tryptophan, arachidonic acid, and biotin, respectively, could serve as potential biomarkers of stress exposure. Furthermore, Spearman's correlation analysis showed strong relationships between the four potential serum biomarkers and differential bacteria. Overall, gallnut TA may be a potential prebiotic for the prevention and treatment of stress-induced metabolic disorders by targeting intestinal microbiota.

UPLC-Orbitrap-MS/MS Combined With Biochemical Analysis to Determine the Growth and Development of Mothers and Fetuses in Different Gestation Periods on Tibetan Sow Model.

Pregnancy is a complex and dynamic process, the physiological and metabolite changes of the mother are affected by different pregnancy stages, but little information is available about their changes and potential mechanisms during pregnancy, especially in blood and amniotic fluid. Here, the maternal metabolism rules at different pregnancy stages were investigated by using a Tibetan sow model to analyze the physiological hormones and nutrient metabolism characteristics of maternal serum and amniotic fluid as well as their correlations with each other. Our results showed that amniotic fluid had a decrease (P < 0.05) in the concentrations of glucose, insulin and hepatocyte growth factor as pregnancy progressed, while maternal serum exhibited the highest concentrations of glucose and insulin at 75 days of gestation (P < 0.05), and a significant positive correlation (P < 0.05) between insulin and citric acid. Additionally, T4 and cortisol had the highest levels during late gestation (P < 0.05). Furthermore, metabolomics analysis revealed significant enrichment in the citrate cycle pathway and the phenylalanine/tyrosine/tryptophan biosynthesis pathway (P < 0.05) with the progress of gestation. This study clarified the adaptive changes of glucose, insulin and citric acid in Tibetan sows during pregnancy as well as the influence of aromatic amino acids, hepatocyte growth factor, cortisol and other physiological indicators on fetal growth and development, providing new clues for the normal development of the mother and the fetus, which may become a promising target for improving the well-being of pregnancy.

Aspartate Metabolism Facilitates IL-1ß Production in Inflammatory Macrophages.

Increasing evidence support that cellular amino acid metabolism shapes the fate of immune cells; however, whether aspartate metabolism dictates macrophage function is still enigmatic. Here, we found that the metabolites in aspartate metabolism are depleted in lipopolysaccharide (LPS) plus interferon gamma (IFN-γ)-stimulated macrophages. Aspartate promotes interleukin-1ß (IL-1ß) secretion in M1 macrophages. Mechanistically, aspartate boosts the activation of hypoxia-inducible factor-1α (HIF-1α) and inflammasome and increases the levels of metabolites in aspartate metabolism, such as asparagine. Interestingly, asparagine also accelerates the activation of cellular signaling pathways and promotes the production of inflammatory cytokines from macrophages. Moreover, aspartate supplementation augments the macrophage-mediated inflammatory responses in mice and piglets. These results uncover a previously uncharacterized role for aspartate metabolism in directing M1 macrophage polarization.