Liver transcriptomic networks reveal main biological processes associated with feed efficiency in beef cattle.

BACKGROUND: The selection of beef cattle for feed efficiency (FE) traits is very important not only for productive and economic efficiency but also for reduced environmental impact of livestock. Considering that FE is multifactorial and expensive to measure, the aim of this study was to identify biological functions and regulatory genes associated with this phenotype. RESULTS: Eight genes were differentially expressed between high and low feed efficient animals (HFE and LFE, respectively). Co-expression analyses identified 34 gene modules of which 4 were strongly associated with FE traits. They were mainly enriched for inflammatory response or inflammation-related terms. We also identified 463 differentially co-expressed genes which were functionally enriched for immune response and lipid metabolism. A total of 8 key regulators of gene expression profiles affecting FE were found. The LFE animals had higher feed intake and increased subcutaneous and visceral fat deposition. In addition, LFE animals showed higher levels of serum cholesterol and liver injury biomarker GGT. Histopathology of the liver showed higher percentage of periportal inflammation with mononuclear infiltrate. CONCLUSION: Liver transcriptomic network analysis coupled with other results demonstrated that LFE animals present altered lipid metabolism and increased hepatic periportal lesions associated with an inflammatory response composed mainly by mononuclear cells. We are now focusing to identify the causes of increased liver lesions in LFE animals.

Effects of ß-Glucan Supplementation on LPS-Induced Endotoxemia in Horses.

ß-glucan is part of the cell wall of fungi and yeasts and has been known for decades to have immunomodulating effects on boosting immunity against various infections as a pathogen-associated molecular pattern that is able to modify biological responses. ß-glucan has been used in rat models and in vitro studies involving sepsis and SIRS with good results, but this supplement has not been evaluated in the treatment of endotoxemia in horses. This study aims to evaluate the effects of preventive supplementation with ß-glucan in horses submitted to endotoxemia by means of inflammatory response modulation. Eight healthy horses, both male and female, aged 18 ± 3 months, weighing 300 ± 100 kg of mixed breed, were randomly assigned to two groups of four animals, both of which were subjected to the induction of endotoxemia via the intravenous administration of E. coli lipopolysaccharides (0.1 µg/kg). For 30 days before the induction of endotoxemia, horses in the ß-glucan group (GB) received 10 mg/kg/day of ß-glucan orally, and horses in the control group (GC) received 10 mg/kg/day of 0.9% sodium chloride orally. The horses were submitted to physical exams, including a hematological, serum biochemistry, and peritoneal fluid evaluation, and the serum quantification of cytokines TNF-α, IL-6, IL-8, and IL-10. For statistical analysis, the normality of residues and homogeneity of variances were verified; then, the variables were analyzed as repeated measures over time, checking the effect of treatment, time, and the interaction between time and treatment. Finally, the averages were compared using Tukey's test at a significance level of 5%. Horses from both experimental groups presented clinical signs and hematological changes in endotoxemia, including an increase in heart rate and body temperature, neutrophilic leukopenia, an increase in serum bilirubin, glucose, lactate, and an increase in TNF-α, IL-6, and IL-10. Hepatic and renal function were not compromised by ß-glucan supplementation. GB presented higher mean values of the serum total protein, globulins, and IL-8 compared to that observed in GC. In the peritoneal fluid, horses from GB presented a lower mean concentration of neutrophils and a higher mean concentration of macrophages compared to the GC. It was concluded that preventive supplementation of ß-glucan for thirty days modulated the immune response, as evidenced by increasing serum total proteins, globulins, IL-8, and changes in the type of peritoneal inflammatory cells, without effectively attenuating clinical signs of endotoxemia in horses. Considering the safety of ß-glucan in this study, the results suggest the potential clinical implication of ß-glucan for prophylactic use in horse endotoxemia.

Complications following transcutaneous cecal trocarization in horses with a cattle trocar and a cecal needle.

Percutaneous decompression of the cecum is a procedure that could be considered for horses with cecal gas distension. The aim of this study was to identify complications such as peritonitis and clinically relevant peritonitis (CRP) after transabdominal cecal trocarization in healthy horses using a cattle trocar and a cecal needle. Mixed breed horses were assigned to three groups (n = 6): horses that underwent trocarization with a cecal needle (G1) or a cattle trocar (G2), and a control group (CG) without cecal trocarization. The same horses were used in each group, respecting a three-month washout period between studies. A physical examination, serial blood, and peritoneal fluid sampling were performed, prior to cecal trocarization and 2, 6 and 12 hours after the first collection and 1, 2, 3, 7, and 14 days after the procedure. Acute-phase proteins in blood and peritoneal fluid were analyzed by polyacrylamide gel electrophoresis. Horses with a high cell count in the peritoneal fluid (i.e., 10,000 cells/µl) were considered to have peritonitis and CRP if they met at least two of the following clinical criteria: anorexia, lethargy, tachycardia, tachypnea, fever, ileus, abnormal oral mucous membrane color, abnormal white blood cells count, or high blood fibrinogen concentration (> 5 g/L). All horses recovered from cecal trocarization and abdominocentesis with no major complications. Cecal trocarization caused cytologic evidence of peritonitis in G1 and G2 during the 14 days of evaluation. CRP was not observed, although a decrease in cecal motility was observed in G1 and G2 during the experimental period and three horses, one from G1 and two from G2, showed a single moment of fever. None of the groups showed leukopenia or leukocytosis, although blood neutrophil count decreased at D7 and D14 in G1 and at D14 in G2 (p ≤ 0.05). After cecal trocarization, an increase in the total nucleated cells count, total proteins, globulins, alkaline phosphatase and acute phase proteins were observed in the peritoneal fluid of G1 and G2 during the 14 days of evaluation (p ≤ 0.05), without causing clinically relevant peritonitis. Transcutaneous cecal trocarization promotes peritonitis, which is more intense with a cattle trocar than with a cecal needle. The cecal needle should be considered for cecal trocarization of horses with cecal tympany.

Nephrin and Podocin mRNA Detection in Urine Sediment of Dogs with Chronic Kidney Disease: Preliminary Observations.

Introduction: Dogs with chronic kidney disease (CKD) may have alterations in the glomerular filtration barrier, including podocyte loss. Detection of podocyte mRNA in urine could be useful for assessing podocyturia in dogs with kidney disease. The objective of this study was to evaluate the presence of nephrin mRNA (NPHS1) and podocin mRNA (NPHS2) in urine sediments of dogs with naturally occurring CKD and healthy dogs. Material and Methods: Twenty-four dogs, 14 with CKD and 10 as healthy controls, underwent clinical evaluation. The dogs with CKD were divided into two groups, according to the International Renal Interest Society criteria: stage 1 or 2 CKD (n = 5) and stage 3 or 4 CKD (n = 9). Urine was collected by catheterisation or free catch and RNA isolation from the urine sediments was optimised using glycogen as a co-precipitant. Detection of NPHS1 and NPHS2 in the sediment samples was performed using quantitative real-time PCR. Results: Both types of mRNA were detected in samples from all groups, but the percentages of detection were higher in the group of dogs with stage 1 or 2 CKD and lower in the group of dogs with stage 3 or 4 disease. Conclusion: Physiological podocyturia was observed in healthy dogs, and the results suggest differential podocyturia in dogs with CKD, according to the stage of the disease, i.e. an increase in podocyturia in dogs at stage 1 or 2 and a reduction in podocyturia in dogs at stage 3 or 4.

Congenital Transmission of Toxoplasma gondii After Experimental Reinfection With Brazilian Typical Strains in Chronically Infected Sheep.

Toxoplasma gondii is a cause of congenital diseases, miscarriages and stillbirths in production animals. In Brazil, non-archetypal genotypes of the parasite may be related to severe disease. Experimental infection with T. gondii was studied in sheep to analyse congenital transmission-related parameters in reinfections with different Brazilian parasite strains. Thirteen T. gondii-seronegative sheep were orally infected with 2 × 103oocysts for the primary infection: G1 (4 animals) were inoculated with TgCatBr71 strain (Type BrI genotype) and G2 andG3 (5 and 4 animals, respectively) withTgCatBr60 strain (Type BrIII genotype). After chronification of infection, the animals were impregnated. A second infection was performed after 60 days of gestation. TheG1 andG3 animals were inoculated withTgCatBr60BrIII and the G2 animals withTgCatBr71 BrI oocysts. The effects of reinfection were compared with a control group (5 animals) through physical examination, ultrasound imaging and serology. Ovine experimental infections were evaluated using mouse bioassays, molecular analysis, serological tests, histopathology, and immunohistochemistry. No abortions occurred; a seropositive lamb and a mummified fetus from G2-BrIIIxBrI were produced. The vertical transmission rate detected in lambs from chronically infected sheep was 31.6% (6/19). It is demonstrated that reinfection and subsequent congenital transmission occured in one sheep with a primary Brl infection challenged with BrIII genotype of T. gondii. In a twin pregnancy from G2-BrIIIxBrI, congenital transmission from a latent infection was detected in both lambs. Congenital transmission could not be tracked in three lambs. Overall, previous T. gondii infection may fail to protect against congenital transmission from a reinfection and primary infection induced insufficient protection against vertical transmission which must be taken into account in decision-making for the use of seropositive animals as breeders. Similar trials with larger groups and contemplating host cellular immune response studies should be conducted to evaluate the actual impact of T. gondii reinfection involving different strains in sheep.

Determination of serum aflatoxin B1-lysine to evaluate the efficacy of an aflatoxin-adsorbing feed additive in pigs fed an aflatoxin B1-contaminated diet.

In this study, serum aflatoxin B1 (AFB1)-lysine was determined in order to evaluate the in vivo efficacy of a hydrated sodium calcium aluminosilicate (HSCAS) in pigs fed AFB1. Twenty-four 49-day-old crossbred barrows were maintained in individual cages and allowed ad libitum access to feed and water. A completely randomized design was used with six animals assigned to each of four dietary treatments for 21 days as follows: (A) basal diet (BD), (B) BD supplemented with 0.5 % HSCAS, (C) BD supplemented with 1.1 mg/kg AFB1, and (D) BD supplemented with 0.5 % HSCAS and 1.1 mg/kg AFB1. HSCAS was able to alleviate the toxic effects of AFB1 on pigs and reduce (P < 0.05) the levels of serum AFB1-lysine. Cumulative reductions of adduct yield values, calculated through the equation [(pg AFB1-lysine/mg albumin) / (µg AFB1/kg body weight)], were 53.0, 62.8, and 72.1 after 7, 14, and 21 days of oral exposure, respectively. AFB1-lysine has potential as an AFB1-specific biomarker for diagnostic purposes and for evaluating the efficacy of chemoprotective interventions in pigs.