Effect of dietary stevia-based sweetener on body weight and humoral immune response of broiler chickens.

BACKGROUND AND AIM: Steviol glycosides extracted from the leaves of Stevia rebaudiana Bertoni have been of much consideration recently because of their beneficial effects on health, raising the possibilities for improving farm animals' health. Although some studies on stevia's dietary effect on body weight gain are available, few studies have been conducted to evaluate stevioside supplementation on immune response in broilers. This experiment aimed to analyze how a stevia-based sweetener can affect broiler chickens' growth performance and humoral response. MATERIALS AND METHODS: In this experiment, one hundred and twenty 1-day-old Cobb-line broiler chicks fed with commercial starter/grower diets were included in three groups and supplemented with stevia-based sweetener at levels 0, 80, and 160 ppm, respectively. Chickens were weighed on day 0 and every 7 days for the next 6 weeks. Chicks were then immunized on days 10 and 24 with a Newcastle and infectious bronchitis vaccine and blood sampled on days 7, 24, and 35. Serologic assays were performed to detect specific antibody levels. RESULTS: The body weight means and body weight gain on day 42 were found to be significantly higher in birds from the group fed with 80 ppm of stevia-based sweetener than those in the control group and slightly higher than those in the group supplemented with 160 ppm of stevia-based sweetener. Likewise, on day 35, antibodies against the Newcastle disease virus were higher in the treatment groups. Immune response to infectious bronchitis virus vaccination was not statistically different among the three groups through the experiment. CONCLUSION: Stevia-based sweetener at 80 ppm in commercial-based diets improved body weight gain and immune response in broiler chickens at the market age.

Ovine Progressive Pneumonia: Diagnosis and Seroprevalence in the South of Sonora, Mexico.

Ovine progressive pneumonia (OPP) is the most severe presentation of small ruminant lentivirus (SRLV) infection known as Maedi-Visna. Serological evidence in Mexico of the presence of this lentivirus was published in 1986. After that, studies revealed that SRLVs have a broad distribution in Mexico by detecting antibodies or/and molecular tests; however, a descriptive case of the disease has not been published. This work's objective was to describe the diagnosis of a case of OPP through lesion description, serology, and molecular test. The histopathological study showed that lymph follicular hyperplasia, interstitial pneumonia, and smooth muscle hyperplasia were presented. The serological test demonstrated specific antibodies against the Maedi-Visna virus, and PCR analysis demonstrated a positive outcome. These results include the criteria for the diagnosis of OPP. The serological prevalence of this disease is presented, contributing to the knowledge of the ecology of this disease in the world. This work is the first case report of ovine progressive pneumonia in Mexico and evidence of seroprevalence in sheep herds from Sonora, Mexico.

Collared peccary (Pecari tajacu) are susceptible to porcine reproductive and respiratory syndrome virus (PRRSV).

Collared peccary (Pecari tajacu) and pigs (Sus scrofa) are two members of superfamily Suoidea that coexist in the Americas and share some of the same viral infections. Although porcine reproductive and respiratory syndrome virus (PRRSV) is among the most impactful pathogens of swine on a worldwide basis, the susceptibility of peccaries to PRRSV has not been investigated. In this study, three peccaries were intramuscularly inoculated with a PRRSV-2 field virus. One PRRSV-inoculated pig served as a positive control and two pigs and one peccary as negative controls. Serum samples were collected at regular intervals over a 23-day observation period and tested by PRRSV rtRT-PCR and isotype-specific (IgM, IgA, IgG) PRRSV ELISAs. The detection of viremia (DPI 3-23) and a PRRSV-specific humoural immune response (≥DPI 10) supported the conclusion that collared peccary are susceptible to PRRSV. The results raise questions regarding the natural history of PRRSV in non-Sus members of superfamily Suoidea and, more broadly, their role in the evolution and ecology of PRRSV.

Seropositivity for Trypanosoma cruzi in domestic dogs from Sonora, Mexico.

BACKGROUND: Chagas disease is an important health problem in Latin America due to its incapacitating effects and associated mortality. Studies on seropositivity for Trypanosoma cruzi in Mexican dogs have demonstrated a direct correlation between seropositivity in humans and dogs, which can act as sentinels for the disease in this region. The objective of this study was to determine the seropositivity for T.cruzi infection in dogs from Sonora, a northern borderstate of Mexico. METHODS: Responsible pet owners were selected at random from an urban area of Empalme municipality, Sonora, Mexico, and from there, 180 dog samples were collected. Anti-T. cruzi antibodies were determined using the enzyme-linked immunosorbent assay (ELISA) method. Reactive ELISA sera were processed by indirect immunofluorescence to confirm the presence of anti-T. cruzi antibodies. For the statistical analysis, chi-square tests were conducted. RESULTS: Dogs' sera showed a seropositivity rate of 4.44%. The rate of seropositivity was not associated with the dogs' age, sex, or socioeconomics pertaining to the geographical area. One sample (1/180, 0.55%) showed the acute state of the disease. CONCLUSIONS: The study found a presence of anti-T. cruzi antibodies in dogs in this area, which suggests vector transmission. There is a need for active surveillance programs throughout the state of Sonora and vector control strategies should also be implemented in endemic regions.