Evidence for functional G-coupled protein receptors 43 and 120 in subcutaneous and intramuscular adipose tissue of Angus crossbred steers

We conducted 3 independent experiments to demonstrate functional G-coupled protein receptor 43 (GPR43) and GPR120 in bovine intramuscular (i.m.) and subcutaneous (s.c.) adipose tissues. We hypothesized that media volatile fatty acids and long-chain fatty acids would affect cAMP-activated protein kinase-alpha (AMPKα) protein expression and cAMP concentrations differently in i.m. and s.c. adipose tissue. Experiment 1: oleic acid (18:1n-9) decreased phosphorylated AMPKα protein (p-AMPKα) and the p-AMPKα/AMPKα protein ratio in i.m. preadipocytes, increased the p-AMPKα/AMPKα protein ratio in bovine satellite cells, and had no effect in s.c. preadipocytes. Experment 2: ex vivo explants from the 5th to 8th longissimus thoracic rib muscle section of Angus crossbred steers were cultured 48 hr in media containing 0.25 µM ciglitizone, 5 mM glucose, and 5 mM acetate, in the absence or the presence of 100 µM oleic acid. Oleic acid increased acetate incorporation into fatty acids and GPR43 gene expression in i.m. adipose tissue (P < 0.05), but oleic acid had no effect on fatty acid synthesis or GPR43 expression in s.c. adipose tissue. Experiment 3: fresh s.c. and i.m. adipose tissue from the 5th to 8th longissimus thoracic rib muscle section of Angus crossbred steers was transferred immediately to 6-well culture plates containing 3 mL of KHB/Hepes/5 mM glucose. Samples were preincubated with 0.5 mM theophylline plus 10 μM forskolin for 30 min, after which increasing concentrations of acetate or propionate (0, 10⁻³, 10^−2.3, and 10⁻³ M) in the absence or the presence of 100 μM oleic acid or 100 µM palmitic acid (16:0) were added to the incubation media. Acetate had no effect on forskolin-stimulated cAMP production in s.c. adipose tissue but decreased cAMP in i.m. adipose tissue (P < 0.05); this indicates a functional GPR43 receptor in i.m. adipose tissue. The combination of 10⁻² M acetate and oleic acid decrease cAMP production in s.c. adipose tissue, consistent with GPR120 receptor activity, but oleic acid and palmitic acid attenuated the depression of cAMP production caused by acetate in i.m. adipose tissue. Palmitic acid depressed cAMP production in s.c. adipose tissue, and increased cAMP production in i.m. adipose tissue (P < 0.05). Propionate had no effect on cAMP production in s.c. or i.m. adipose tissue. These results provide evidence for functional GPR43 receptors in i.m. adipose tissue and GPR120 receptors in s.c. adipose tissue, both of which would suppress lipolysis.     

Poor maternal nutrition inhibits muscle development in ovine offspring

Background

Maternal over and restricted nutrition has negative consequences on the muscle of offspring by reducing muscle fiber number and altering regulators of muscle growth. To determine if over and restricted maternal nutrition affected muscle growth and gene and protein expression in offspring, 36 pregnant ewes were fed 60%, 100% or 140% of National Research Council requirements from d 31 ± 1.3 of gestation until parturition. Lambs from control-fed (CON), restricted-fed (RES) or over-fed (OVER) ewes were necropsied within 1 d of birth (n = 18) or maintained on a control diet for 3 mo (n = 15). Semitendinosus muscle was collected for immunohistochemistry, and protein and gene expression analysis.

Results

Compared with CON, muscle fiber cross-sectional area (CSA) increased in RES (58%) and OVER (47%) lambs at 1 d of age (P < 0.01); however at 3 mo, CSA decreased 15% and 17% compared with CON, respectively (P < 0.01). Compared with CON, muscle lipid content was increased in OVER (212.4%) and RES (92.5%) at d 1 (P < 0.0001). Muscle lipid content was increased 36.1% in OVER and decreased 23.6% in RES compared with CON at 3 mo (P < 0.0001). At d 1, myostatin mRNA abundance in whole muscle tended to be greater in OVER (P = 0.07) than CON. Follistatin mRNA abundance increased in OVER (P = 0.04) and tended to increase in RES (P = 0.06) compared with CON at d 1. However, there was no difference in myostatin or follistatin protein expression (P > 0.3). Phosphorylated Akt (ser473) was increased in RES at 3 mo compared with CON (P = 0.006).

Conclusions

In conclusion, maternal over and restricted nutrient intake alters muscle lipid content and growth of offspring, possibly through altered gene and protein expression.     

Regulatory role of l-proline in fetal pig growth and intestinal epithelial cell proliferation

l-proline (Pro) is a precursor of ornithine, which is converted into polyamines via ornithine decarboxylase (ODC). Polyamines plays a key role in the proliferation of intestinal epithelial cells. The study investigated the effect of Pro on polyamine metabolism and cell proliferation on porcine enterocytes in vivo and in vitro. Twenty-four Huanjiang mini-pigs were randomly assigned into 1 of 3 groups and fed a basal diet that contained 0.77% alanine (Ala, iso-nitrogenous control), 1% Pro or 1% Pro + 0.0167% α-difluoromethylornithine (DFMO) from d 15 to 70 of gestation. The fetal body weight and number of fetuses per litter were determined, and the small and large intestines were obtained on d 70 ± 1.78 of gestation. The in vitro study was performed in intestinal porcine epithelial (IPEC-J2) cells cultured in Dulbecco''s modified Eagle medium-high glucose (DMEM-H) containing 0 μmol/L Pro, 400 μmol/L Pro, or 400 μmol/L Pro + 10 mmol/L DFMO for 4 d. The results showed that maternal dietary supplementation with 1% Pro increased fetal weight; the protein and DNA concentrations of the fetal small intestine; and mRNA levels for potassium voltage-gated channel, shaker-related subfamily, member 1 (Kv1.1) in the fetal small and large intestines (P < 0.05). Supplementing Pro to either gilts or IPEC-J2 cells increased ODC protein abundances and polyamine concentrations in the fetal intestines and IPEC-J2 cells (P < 0.05). In comparison with the Pro group, the combined administration of Pro and DFMO reduced the expression of ODC protein and spermine concentration in the fetal intestine, as well as the concentrations of putrescine, spermidine and spermine in IPEC-J2 cells (P < 0.05). Meanwhile, the percentage of cells in the S-phase and the mRNA levels of proto-oncogenes c-fos and c-myc were increased in response to Pro supplementation, whereas depletion of cellular polyamines with DFMO increased tumor protein p53 (p53) mRNA levels (P < 0.05). Taken together, dietary supplementation with Pro improved fetal pig growth and intestinal epithelial cell proliferation via enhancing polyamine synthesis.     

The interaction of nitrous oxide and fentanyl on the minimum alveolar concentration of sevoflurane blocking motor movement (MACNM) in dogs

The study objective was to determine the effects of 70% nitrous oxide (N₂O) and fentanyl on the end-tidal concentration of sevoflurane necessary to prevent movement (MAC_NM) in response to noxious stimulation in dogs. Six healthy, adult, intact male, mixed-breed dogs were used on 3 occasions in a randomized crossover design. After induction of anesthesia with sevoflurane, each of the following treatments was randomly administered: fentanyl loading dose (Ld) of 15 μg/kg and infusion of 6 μg/kg per hour [treatment 1 (T1)], 70% N₂O (T2), or fentanyl (Ld of 15 μg/kg and infusion of 6 μg/kg per hour) combined with 70% N₂O (T3). Each dog received each of the 3 treatments once during the 3-week period. Determination of MAC_NM was initiated 90 min after the start of each treatment. The values were compared using the baseline MAC_NM, which had been determined in a previous study on the same group of dogs. Data were analyzed using a mixed-model analysis of variance (ANOVA) and Tukey-Kramer tests, and expressed as least squares mean ± SEM. The baseline MAC_NM decreased by 36.6 ± 4.0%, 15.0 ± 4.0%, and 46.0 ± 4.0% for T1, T2, and T3, respectively (P < 0.05), and differed (P < 0.05) among treatments. Mean fentanyl plasma concentrations did not differ (P ≥ 0.05) between T1 (3.70 ± 0.56 ng/mL) and T3 (3.50 ± 0.56 ng/mL). The combination of fentanyl and N₂O resulted in a greater sevoflurane MAC_NM sparing effect than either treatment alone.     

Urinary cortisol‐creatinine ratio in dogs with hypoadrenocorticism

BackgroundBasal serum cortisol (BSC) ≥2 μg/dL (>55 nmol/L) has high sensitivity but low specificity for hypoadrenocorticism (HA).ObjectiveTo determine whether the urinary corticoid:creatinine ratio (UCCR) can be used to differentiate dogs with HA from healthy dogs and those with diseases mimicking HA (DMHA).AnimalsNineteen healthy dogs, 18 dogs with DMHA, and 10 dogs with HA.MethodsRetrospective study. The UCCR was determined on urine samples from healthy dogs, dogs with DMHA, and dogs with HA. The diagnostic performance of the UCCR was assessed based on receiver operating characteristics (ROC) curves, calculating the area under the ROC curve.ResultsThe UCCR was significantly lower in dogs with HA (0.65 × 10⁻⁶; range, 0.33‐1.22 × 10⁻⁶) as compared to healthy dogs (3.38 × 10⁻⁶; range, 1.11‐17.32 × 10⁻⁶) and those with DMHA (10.28 × 10⁻⁶; range, 2.46‐78.65 × 10⁻⁶) (P < .0001). There was no overlap between dogs with HA and dogs with DMHA. In contrast, 1 healthy dog had a UCCR value in the range of dogs with HA. The area under the ROC curve was 0.99. A UCCR cut‐off value of <1.4 yielded 100% sensitivity and 97.3% specificity in diagnosing HA.Conclusions and Clinical ImportanceThe UCCR seems to be a valuable and reliable screening test for HA in dogs. The greatest advantage of this test is the need for only a single urine sample.     

Clinicopathologic features,comorbid diseases,and prevalence of pulmonary hypertension in dogs with bronchomalacia

BackgroundReports of clinicopathologic features of bronchomalacia (BM) differ because of inconsistent definitions and frequent prevalence of comorbid cardiopulmonary disease. Pulmonary hypertension (PH) secondary to BM is poorly described.ObjectivesDogs with BM will be older but of any somatotype, and increased expiratory effort, ≥1 comorbid disease, and PH will be more common than in dogs without BM.AnimalsClient‐owned dogs (n = 210) evaluated for respiratory signs.MethodsMedical records of dogs with paired inspiratory: expiratory‐breath‐hold computed tomography, tracheobronchoscopy, or both between January 2016 and December 2019 were retrospectively reviewed. Comparisons between dogs with and without BM using Mann‐Whitney rank sum or χ ² tests (P < .05 significant were made). Because of high numbers of variables, criteria with high prevalence (>25%) were identified (n = 10) for univariate analysis (P < .005 significant). Significant variables were submitted for multivariate analysis.ResultsBronchomalacia was identified in 41% of dogs of all sizes/somatotypes; 38% were >10 kg. All dogs with BM had ≥1 comorbid cardiopulmonary disorder. Dogs with BM were significantly older (P < .001), smaller (P < .001), and were more likely diagnosed with tracheal or mainstem bronchial collapse (P < .001) or bronchiectasis (P < .001). Multivariate analysis confirmed associations with age, tracheal or mainstem bronchial collapse, and bronchiectasis. In dogs with BM, PH was more prevalent.Conclusions and Clinical ImportanceAlthough significantly more common in older, smaller dogs, BM occurs in dogs of all sizes and in all instances with comorbidities. Echocardiography should be considered in dogs with BM to identify PH.     

Expression of hypoxia-inducible factor-1α and vascular density in mammary adenomas and adenocarcinomas in bitches

Background

The study aimed at examining hypoxia-inducible factor (HIF)1α expression in adenocarcinomas and adenomas in bitches in regard to tumour malignancy grade, proliferation, apoptosis and vascularisation. Therefore, paraffin sections of 15 adenomas and 64 adenocarcinomas sampled from 79 dogs aged 6 to 16 years were analysed.

Results

A significantly higher HIF-1α expression was noted in adenocarcinomas in comparison to adenomas (P < 0.0004). Moreover, HIF-1α expression in adenocarcinomas correlated positively with tumour malignancy grade (r = 0.59, P < 0.05), Ki-67 antigen expression (r = 0.43; P < 0.0005), TUNEL-positive cells (r = 0.62, P < 0001) and tumour vascularity measured by quantification of vessels characterized by the expression of von Willebrand Factor (r = 0.57, P < 0.05).

Conclusion

Results of this study indicate a similar biological role of HIF-1α in dogs and in humans, which may confirm suitability of the animal model in investigations on progression of tumours in humans.     

Diurnal variations of central corneal thickness and intraocular pressure in dogs from 8:00 am to 8:00 pm

Diurnal variations in central corneal thickness (CCT) and intraocular pressure (IOP) and their relationships were studied in healthy dogs. Central corneal thickness was measured by ultrasonic pachymetry and IOP by applanation tonometry in 16 beagle dogs. Measurements were taken every 90 min over 12 h (08:00 am to 08:00 pm). The mean CCT and IOP values obtained during the sampling period were 545.6 ± 21.7 μm (range: 471 to 595 μm) and 15 ± 2.2 mmHg (range: 10 to 19 mmHg), respectively. The CCT and IOP showed statistically significant decreases at 6:30 pm and 5:00 pm, respectively (P < 0.001). Central corneal thickness and IOP values were lower in the afternoon/evening than in the morning and were positively correlated. Both findings are important for the diagnostic interpretation of IOP values in dogs.     

A selectively suppressing amino acid transporter: Sodium-coupled neutral amino acid transporter 2 inhibits cell growth and mammalian target of rapamycin complex 1 pathway in skeletal muscle cells

Sodium-coupled neutral amino acid transporter 2 (SNAT2), also known as solute carrier family 38 member 2 (SLC38A2), is expressed in the skeletal muscle. Our research previously indicated that SNAT2 mRNA expression level in the skeletal muscle was modulated by genotype and dietary protein. The aim of this study was to investigate the key role of the amino acid transporter SNAT2 in muscle cell growth, differentiation, and related signaling pathways via SNAT2 suppression using the inhibitor α-methylaminoisobutyric acid (MeAIB). The results showed that SNAT2 suppression down-regulated both the mRNA and protein expression levels of SNAT2 in C2C12 cells, inhibited cell viability and differentiation of the cell, and regulated the cell distribution in G0/G1 and S phases (P < 0.05). Meanwhile, most of the intercellular amino acid content of the cells after MeAIB co-culturing was significantly lower (P < 0.05). Furthermore, the mRNA expression levels of system L amino acid transporter 1 (LAT1), silent information regulator 1, and peroxisome proliferator-activated receptor-gamma co-activator 1 alpha, as well as the protein expression levels of amino acid transporters LAT1 and vacuolar protein sorting 34, were all down-regulated. The phosphorylated protein expression levels of mammalian target of rapamycin (mTOR), regulatory-associated protein of mTOR, 4E binding protein 1, and ribosomal protein S6 kinase 1 after MeAIB treatment were also significantly down-regulated (P < 0.05), which could contribute to the importance of SNAT2 in amino acid transportation and skeletal muscle cell sensing. In conclusion, SNAT2 suppression inhibited C2C12 cell growth and differentiation, as well as the availability of free amino acids. Although the mTOR complex 1 signaling pathway was found to be involved, its response to different nutrients requires further study.     

Effects of extended postmortem aging and intramuscular location on protein degradation,muscle fiber morphometrics,and tenderness of beef longissimus lumborum and semitendinosus steaks

The objective of this study was to determine effects of extended aging and intramuscular location on Warner-Bratzler shear force (WBSF), muscle fiber cross-sectional area (CSA), and protein degradation of semitendinosus (ST) and longissimus lumborum (LL) steaks. Left ST and LL were removed from 40 carcasses at 6 d postmortem. The ST was fabricated into five locations (LOC), with LOC 1 being most proximal and LOC 5 being most distal. The posterior LL was fabricated into 3 LOC, with LOC 1 being most anterior. Vacuum sealed ST steaks were aged 7, 14, 28, 56, or 112 d postmortem, while LL steaks were aged 7, 28, or 112 d postmortem at 2 ± 1 °C. A steak from each LOC was assigned to WBSF or laboratory analyses. There were no Day of Aging (DOA) × LOC interactions for all dependent variables (P > 0.06). There were DOA effects for ST and LL WBSF values and degraded 38-kDa desmin (DES; P < 0.01). Day-7 ST-steak WBSF value was greater than all other days (P < 0.01) and day-14 steaks had greater WBSF value than remaining days (P < 0.05). Day-28 ST-steak WBSF values were greater than day 56 and 112 (P < 0.01), which did not differ (P = 0.53). In the LL, day-7 steaks had greater WBSF values than the other two timepoints (P < 0.01) and day-28 steaks had greater (P < 0.01) WBSF values than day-112 steaks. Degraded ST 38-kDa DES content was less on day 7 and 14 compared to all other days (P < 0.03), but did not differ (P = 0.79) from each other. Days 28 and 56 38-kDa DES content was less than day 112 (P < 0.01), but did not differ (P = 0.34) from each other. Degraded LL 38-kDa DES content was less on day 7 than day 28 and 112 (P < 0.02), which did not differ (P = 0.67). There were LOC effects for only ST WBSF and muscle fiber CSA (P < 0.05). Semitendinosus steak LOC 1 and 2 had greater WBSF values than all other locations (P < 0.01), but did not differ (P = 0.32) from each other. Semitendinosus steak LOC 3 and 5 had greater WBSF values than LOC 4 (P < 0.01), but did not differ (P = 0.85) from each other. The CSA of all ST fiber types were largest in LOC 1 compared to all other fiber types (P < 0.01). The CSA of all LOC 2 and 3 fiber types was greater than LOC 4 and 5 (P < 0.01), but were not different from each other (P > 0.81), and LOC 4 had greater CSA than LOC 5 (P < 0.01). Steak aging WBSF value improvements seemed proteolysis catalyzed, while the ST intramuscular tenderness gradient was more likely due to muscle fiber CSA.     

Serum cystatin C concentration can be used to evaluate glomerular filtration rate in small dogs

Serum cystatin C levels (CysC) are used in human medicine to document progressive kidney failure. Although CysC are not thought to be useful for the diagnosis of kidney dysfunction in dogs, there has been no specific consideration of body weight as a confounding issue. The aim of this study was to assess that the utility of CysC for the diagnosis of decreased glomerular filtration rate (GFR) in smaller vs. larger dogs. In clinically healthy dogs, serum creatinine (Cre) and CysC correlate directly with body weight; we found that dogs weighing <20 kg had significantly lower CysC than those weighing ≥20 kg (0.27 ± 0.07 vs. 0.34 ± 0.05 mg/l, respectively, P<0.001). In dogs weighing <20 kg, CysC had superior diagnostic accuracy for the detection of mildly decreased plasma iohexol clearance (PCio) (<1.8 ml/min/kg) compared with Cre (sensitivity 100% vs. 80.9% and specificity 100% vs. 85.7%); this was not true for dogs weighing ≥20 kg. Additionally, using a cut-off PCio of <1.8 ml/min/kg, the area under receiver-operating characteristics curve (AUC) of CysC was significantly higher than that of Cre in dogs weighing <20 kg (P<0.05); this was not true for dogs weighing ≥20 kg (P=0.695). In conclusion, CysC is a useful marker for the detection of a mild decreasing GFR compared with Cre in dogs weighing <20 kg.     

Influence of prior determination of baseline minimum alveolar concentration (MAC) of isoflurane on the effect of ketamine on MAC in dogs

The objective of this study was to determine if prior measurement of the minimum alveolar concentration (MAC) of isoflurane influences the effect of ketamine on the MAC of isoflurane in dogs. Eight mixed-breed dogs were studied on 2 occasions. Anesthesia was induced and maintained using isoflurane. In group 1 the effect of ketamine on isoflurane MAC was determined after initially finding the baseline isoflurane MAC. In group 2, the effect of ketamine on isoflurane MAC was determined without previous measure of the baseline isoflurane MAC. In both groups, MAC was determined again 30 min after stopping the CRI of ketamine. Plasma ketamine concentrations were measured during MAC determinations.In group 1, baseline MAC (mean ± SD: 1.18 ± 0.14%) was decreased by ketamine (0.88 ± 0.14%; P < 0.05). The MAC after stopping ketamine was similar (1.09 ± 0.16%) to baseline MAC and higher than with ketamine (P < 0.05). In group 2, the MAC with ketamine (0.79 ± 0.11%) was also increased after stopping ketamine (1.10 ± 0.17%; P < 0.05). The MAC values with ketamine were different between groups (P < 0.05). Ketamine plasma concentrations were similar between groups during the events of MAC determination.The MAC of isoflurane during the CRI of ketamine yielded different results when methods of same day (group-1) versus separate days (group-2) are used, despite similar plasma ketamine concentrations with both methods. However, because the magnitude of this difference was less than 10%, either method of determining MAC is deemed acceptable for research purposes.     

Mulberry leaf powder regulates antioxidative capacity and lipid metabolism in finishing pigs

This study evaluated the potential of mulberry leaf powder as an unconventional feed material for finishing pigs by assessing the growth performance, antioxidative properties, fatty acid profile, and lipid metabolism in 180 Xiangcun black pigs. Pigs with an initial body weight (BW) of 71.64 ± 1.46 kg were randomly assigned to 5 treatment groups, including the control diet and 4 experimental diets. The corn, soybean meal, and wheat bran in the control diet were partly replaced by 3%, 6%, 9%, or 12% mulberry leaf powder in experimental diets. There were 6 replicates (pens) of 6 pigs per replicate in each treatment. Blood and muscle samples were collected after the 50-day feed experiment. Compared with the control group, the 3%, 6%, and 9% mulberry diets had no adverse effect (P > 0.05) on the growth performance of pigs. The serum glutathione peroxidase activity and glutathione concentration increased linearly (P < 0.05) with the increase in dietary mulberry inclusion. There was no significant difference in the relative expression levels of antioxidant-related genes in muscle tissue between the control and mulberry groups. Inclusion of dietary mulberry powder increased (P < 0.05) the content of polyunsaturated fatty acids, especially in the longissimus dorsi (LD) muscle, up-regulated (P < 0.05) the relative mRNA expression level of uncoupling protein-3 in muscle tissue, but down-regulated (P < 0.05) the relative mRNA expression levels of hormone-sensitive lipase, acetyl CoA carboxylase α, lipoprotein lipase, and peroxisome proliferator-activated receptor γ in LD in a linear pattern. The nuclear respiratory factor 2 expression level in the LD muscle of pigs fed the 9% mulberry diet was higher (P < 0.01) than that in the other mulberry groups and control group. The inclusion of less than 12% dietary mulberry did not detrimentally affect the growth performance of Xiangcun black pigs, but enhanced the serum antioxidant property, increased the polyunsaturated fatty acid content, and inhibited lipid oxidation by regulating gene expression levels of lipid metabolism and mitochondrial uncoupling protein in muscle tissue. Mulberry leaves can be utilized as a forage crop in the diet of finishing pigs.     

Clinical evaluation of urinary liver-type fatty acid-binding protein for the diagnosis of renal diseases in dogs

Liver-type fatty acid-binding protein (L-FABP) is a biomarker for the early detection of renal diseases in humans. L-FABP is a cytotoxic oxidation product secreted from the proximal tubules under ischemic and oxidative stress conditions. First, L-FABP gene expression in the kidney and liver was evaluated. Next, the urinary L-FABP concentrations in dogs with or without renal diseases were measured using a novel enzyme-linked immunosorbent assay kit. Urinary L-FABP was normalized relative to urinary creatinine (uCre) concentrations (µg/g uCre). Finally, the relationships between urinary L-FABP and renal biomarkers used in canine medicine or serum alanine transaminase (ALT) as an indicator of liver damage were examined. Serum and urine samples from 94 client-owned dogs including 23 dogs with renal diseases and 71 dogs without renal diseases were used for analysis. Relative L-FABP gene expression was confirmed both in the liver and kidney. Dogs with renal diseases had a significantly higher urinary L-FABP than those without, and its predictive cutoff value was 26 µg/g uCre. Urinary L-FABP was significantly correlated with serum creatinine (r=0.4674, P<0.01), urea nitrogen (r=0.4907, P<0.01), urine specific gravity (r=−0.5100, P<0.01), and urine protein/creatinine ratio (r=0.7216, P<0.01), but not with serum ALT. Hence, dogs with a high urinary L-FABP value were more likely to have renal diseases.     

Antibiotic resistance,antimicrobial residues,and bacterial community diversity in pasture-raised poultry,swine, and beef cattle manures

Animal manure can be a source of antibiotic-resistant genes (ARGs) and pharmaceutical residues; however, few studies have evaluated the presence of ARG in pasture-raised animal production systems. The objective of this study was to examine changes in microbiome diversity and the presence of antibiotic residues (ABRs) on three farms that contained a diverse range of animal species: pasture-raised poultry (broiler and layer), swine, and beef cattle. Total bacterial communities were determined using 16S rRNA microbiome analysis, while specific ARGs (sulfonamide [Sul; Sul1] and tetracycline [Tet; TetA]) were enumerated by qPCR (real-time PCR). Results indicated that the ARG abundances (Sul1 [P < 0.05] and TetA [P < 0.001]) were higher in layer hen manures (16.5 × 10⁻⁴ and 1.4 × 10⁻⁴ µg kg⁻¹, respectively) followed by broiler chickens (2.9 × 10⁻⁴ and 1.7 × 10⁻⁴ µg kg⁻¹, respectively), swine (0.22 × 10⁻⁴ and 0.20 × 10⁻⁴ µg kg⁻¹, respectively) and beef cattle (0.19 × 10⁻⁴ and 0.02 × 10⁻⁴ µg kg⁻¹, respectively). Average fecal TetA ABR tended to be greater (P = 0.09) for broiler chickens (11.4 µg kg⁻¹) than for other animal species (1.8 to 0.06 µg kg⁻¹), while chlortetracycline, lincomycin, and oxytetracycline ABRs were similar among animal species. Furthermore, fecal microbial richness and abundances differed significantly (P < 0.01) both among farms and specific species of animal. This study indicated that the microbial diversity, ABR, ARG concentrations, and types in feces varied from farm-to-farm and from animal species-to-animal species. Future studies are necessary to perform detailed investigations of the horizontal transfer mechanism of antibiotic-resistant microorganisms (ARMs) and ARG.     

Serum Biomarkers of Clinical and Cytologic Response in Dogs with Idiopathic Immune‐Mediated Polyarthropathy

Background

Immune‐mediated polyarthopathy (IMPA) is common in dogs, and is monitored by serial arthrocenteses.

Hypothesis/Objectives

Plasma C‐reactive protein (CRP), interleukin‐6 (IL‐6), and CXCL8 (interleukin‐8) would serve as noninvasive markers of joint inflammation in IMPA.

Animals

Nine client‐owned dogs with idiopathic IMPA; 6 healthy controls.

Methods

Prospective study. Plasma CRP, IL‐6, and CXCL8 were measured by ELISA at baseline, 2, and 4 weeks during treatment with prednisone at 50 mg/m²/day. Arthrocenteses, the canine brief pain inventory (CBPI), and accelerometry collars were used to assess joint inflammation, lameness, and mobility at all 3 time points.

Results

C‐reactive protein concentrations were higher in IMPA dogs (median 91.1 μg/mL, range 76.7–195.0) compared with controls (median <6.3 μg/mL, <6.3–13.7; P = .0035), and were significantly lower at week 2 (10.6 μg/mL, <6.3–48.8) and week 4 (<6.3 μg/mL, <6.3–24.4; P < .001).C‐reactive protein was correlated with median CBPI scores (r = 0.68; P = .0004), joint cellularity (r = 0.49, P = .011), and mobility by accelerometry (r = −0.42, P = .048). Plasma IL‐6 concentrations were also higher in IMPA dogs (median 45.9 pg/mL), compared with controls (median <15.7 pg/mL; P = .0008). IL‐6 was lower in IMPA dogs by week 4 (<15.7 pg/mL; P = .0099), and was modestly correlated with CBPI scores (r = 0.47, P = .023). CXCL8 did not differ significantly between IMPA and healthy dogs.

Conclusions

Plasma CRP and IL‐6 might be useful surrogate markers of synovial inflammation and disease activity in dogs with IMPA.     

Comparison of the alkalizing abilities between 1.35% sodium bicarbonate solutions with and without dextrose in healthy calves

The present study aimed to clarify the alkalizing ability of 1.35% isotonic sodium bicarbonate solution (ISBS), which did not contain dextrose, compared with that of 1.35% isotonic bicarbonate sodium solution containing 4.03% dextrose (ISBD) in healthy calves. The calves were intravenously administered with 20.7 mL/kg of the solutions for 30 min as the volume required to correct base deficit of 10 mM. ISBS increased the blood pH, HCO₃⁻, and base excess from 7.44 ± 0.02, 29.6 ± 1.9 mM, and 5.3 ± 2.1 mM to 7.49 ± 0.02, 36.9 ± 2.3 mM, and 13.5 ± 2.6 mM respectively (P<0.05). These factors for the ISBD group increased from 7.41 ± 0.02, 29.0 ± 1.1 mM, and 4.5 ± 1.3 mM to 7.43 ± 0.02, 33.5 ± 1.9 mM, and 9.5 ± 1.7 mM (P<0.05), respectively. Furthermore, in the ISBD group, the relative plasma volume and blood glucose level increased while the K⁺ level decreased, which did not occur in the ISBS group. Therefore, the results revealed that ISBS had better alkalizing ability in calves than ISBD.     

Levetiracetam Rectal Administration in Healthy Dogs

Background

Levetiracetam is used to manage status epilepticus (SE) and cluster seizures (CS) in humans. The drug might be absorbed after rectal administration and could offer a practical adjunct to rectal administration of diazepam in managing SE and CS.

Hypothesis

Levetiracetam is rapidly absorbed after rectal administration in dogs and maintains target serum concentrations for at least 9 hours.

Animals

Six healthy privately owned dogs between 2 and 6 years of age and weighing 10–20 kg.

Methods

Levetiracetam (40 mg/kg) was administered rectally and blood samples were obtained immediately before (time zero) and at 10, 20, 40, 60, 90, 180, 360, and 540 minutes after drug administration. Dogs were observed for signs of adverse effects over a 24‐hour period after drug administration.

Results

C _LEV at 10 minutes was 15.3 ± 5.5 μg/mL (mean, SD) with concentrations in the target range (5–40 μg/mL) for all dogs throughout the sampling period. C _max (36.0 ± 10.7 μg/mL) and T _max (103 ± 31 minutes) values were calculated and 2 disparate groups were appreciated. Dogs with feces in the rectum at the time of drug administration had lower mean C _max values (26.7 ± 3.4 μg/mL) compared with those without (45.2 ± 4.4 μg/mL). Mild sedation was observed between 60 and 90 minutes without other adverse effects noted.

Conclusions and Clinical Importance

This study supports the use of rectally administered levetiracetam in future studies of clinical effectiveness in the management of epileptic dogs.     

Evaluation of vitamin A status on myogenic gene expression and muscle fiber characteristics

A randomized complete block design experiment with 30 yearling crossbred steers (average BW = 436.3 ± 39.8 kg) fed a steam-flaked corn-based diet was used to evaluate the effects dietary vitamin A (Rovimix A 1000; DSM Nutritional Products Ltd., Sisseln, SUI) supplementation on myogenic gene expression and skeletal muscle fiber characteristics during the finishing phase. Steers were blocked by BW (n = 5 blocks; 6 steers/block), randomly assigned to pens (n = 2 steers/pen), and one of the following treatments: no added vitamin A (0 IU; 0.0 IU/kg of dietary dry matter intake of additional vitamin A), vitamin A supplemented at the estimated requirement (2,200 IU; 2,200 IU/kg of dietary dry matter (DM) of additional vitamin A), and vitamin A supplemented at 5× the estimated requirement (11,000 IU; 11,000 IU/kg of dietary DM of additional vitamin A). After all treatments underwent a 91-d vitamin A depletion period, additional vitamin A was top-dressed at feeding via a ground corn carrier. Blood, longissimus muscle, and liver biopsy samples were obtained on days 0, 28, 56, 84, and 112. Biopsy samples were used for immunohistochemical and mRNA analysis. Sera and liver samples were used to monitor circulating vitamin A and true vitamin A status of the cattle. Expression for myosin heavy chain (MHC)-I diminished and rebounded (P = 0.04) over time. The intermediate fiber type, MHC-IIA, had a similar pattern of expression (P = 0.01) to that of MHC-I. On day 84, C/EBPβ expression was also the greatest (P = 0.03). The pattern of PPARγ (P < 0.01) and PPARδ (P < 0.01) expression seemed to mimic that of MHC-I expression, increasing from days 84 to 112. Distribution of MHC-IIA demonstrated a change over time (P = 0.02). Muscle fiber cross-sectional area increased by day (P < 0.01) for each MHC with the notable increase between days 0 and 56. Total nuclei density decreased (P = 0.02) over time. Cells positive for only Myf5 increased (P < 0.01) in density early in the feeding period, then declined, indicating that satellite cells were fusing into fibers. The dual-positive (PAX7+Myf5) nuclei also peaked (P < 0.01) around day 56 then declined. These data indicated that gene expression associated with oxidative proteins may be independent of vitamin A status in yearling cattle.     

Flesh quality of hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) fed with hydrolyzed porcine mucosa-supplemented low fishmeal diet

Iso-nitrogenous and iso-lipidic diets containing 0%, 3%, 6%, 9%, and 12% hydrolyzed porcine mucosa (namely, HPM0, HPM3, HPM6, HPM9, and HPM12) were prepared to evaluate their effects on the growth performance, muscle nutrition composition, texture property, and gene expression related to muscle growth of hybrid groupers (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂). Groupers were fed to apparent satiation at 08:00 and 16:00 every day for a total of 56 days. It was found that the weight gain percentage in the HPM0, HPM3, and HPM6 groups did not differ (P > 0.05). The cooking loss and drip loss of the dorsal muscle in the HPM3 group were lower than those in the HPM6 and HPM9 groups (P < 0.05). The hardness and chewiness of the dorsal muscle in the HPM3 group were higher than those in the HPM0, HPM9, and HPM12 groups (P < 0.05). The gumminess in the HPM3 group was higher than that in the HPM9 and HPM12 groups (P < 0.05). The total essential amino acid content of the dorsal muscle in the HPM12 group was higher than that in the HPM0 group (P < 0.05). The contents of total n-3 polyunsaturated fatty acid and total n-3 highly unsaturated fatty acid, as well as the ratio of n-3/n-6 polyunsaturated fatty acid in the dorsal muscle was higher in the HPM0 group than in all other groups (P < 0.05). The relative expressions of gene myogenic factor 5, myocyte enhancer factor 2c, myocyte enhancer factor 2a, myosin heavy chain, transforming growth factor-beta 1 (TGF-β1), and follistatin (FST) were the highest in the dorsal muscle of the HPM3 group. The results indicated that the growth performance of hybrid grouper fed a diet with 6% HPM and 27% fish meal was as good as that of the HPM0 group. When fish ingested a diet containing 3% HPM, the expression of genes TGF-β1 and FST involved in muscle growth were upregulated, and then the muscle quality related to hardness and chewiness were improved. An appropriate amount of HPM could be better used in grouper feed.