A study of the immunomodulatory effects of coconut oil extract in broilers experimentally infected with velogenic Newcastle disease virus.

Objective: This study aims to evaluate the immunomodulatory effects of coconut oil extract (COE) in broilers experimentally infected with velogenic Newcastle disease virus (vNDV). Methods: A total of 150 broiler birds (day-old) were equally divided into five study groups i.e., negative control, positive control, COE-1, COE-2, and COE-3. On day 10, broilers of groups COE-1, COE-2, and COE-3 were supplemented with 1, 2, and 3 ml of COE respectively per liter of drinking water for 15 days. On day 13, 0.1ml/bird (10-5.25 ELD50) of vNDV was inoculated in broilers of positive control, COE-1, COE-2, and COE-3 groups intramuscularly. During this study, growth performance, morbidity, and mortality rates of each study group were recorded. The antibody titer against NDV was determined on days 7, 14, 21, 28, and 35. The levels of IgY and IgM were also determined on the 7th, 14th, and 21st days post-SRBC inoculation. On day 33, avian tuberculin was injected between the 1st and 2nd toes of the left side (intradermally) to measure lymphoproliferative responses. On day 35, the phagocytic activity in the blood was assessed through a carbon clearance assay by injecting carbon black ink into the right-wing vein. The visceral organs having gross lesions were also collected for histopathology. Results: The COE significantly improved the growth performance, and lowered the morbidity and mortality rates of broilers. There was a significant rise in antibody titers against NDV and levels of IgY and IgM antibodies against SRBC in COE-supplemented broilers. The lymphoproliferative response and phagocytic activity were also enhanced. Among COE-supplemented groups, the broilers of the COE-3 group showed a significant increase in growth performance and boosted immune defense. Conclusions: Coconut oil extract has the potential to boost the growth performance and immune status of broilers. It can be used effectively as a feed additive and alternative to antibiotics to prevent the spread of infectious poultry pathogens.

Seroprevalence and pathological studies of Salmonella infection in commercial white layer birds.

The present study was conducted to determine the seroprevalence and pathology of Salmonella infection in white commercial layer birds of District Faisalabad during June 2018 and June 2020. The current study aimed to determine the isolation, identification of Salmonella gallinarum (S. gallinarum), its cultural prevalence, antimicrobial resistance, molecular characterization, and pathological lesions produced in different organs of commercial layer birds. Initial screening of poultry flocks was done through serum plate agglutination test followed by culturing in different media, motility test, molecular confirmation, and histopathology. Based on the serum plate agglutination test, seroprevalence in the commercial white layer in dead and live flocks was 40.09%. The cultural prevalence of Salmonella in the seropositive group was 75.36% and in the seronegative was 31.84%. Cultural prevalence in the liver of dead birds was 62.06%, in spleen 58.62%, and in cloacal swabs was 67.24%. A total of 178 isolates were characterized through cultural characteristic and motility tests, among them 63.48% isolates were S. gallinarum, and 36.51% isolates were S. pullorum. The antibiogram study revealed that all the tested isolates were resistant to amoxicillin, gentamycin, kanamycin, doxycyclin, and tetracyclin. While tested isolates were sensitive to ciprofloxacin against S. gallinarum. Pathologically liver was friable, showing bonze discoloration with focal necrosis, enteritis of various grades, mottled white spleen, and enlarged kidneys were found. Microscopically, leukocytic infiltration with focal necrosis and degeneration, in mucosa and submucosa of intestinal inflammatory cells were observed. In conclusion, the seroprevalence, antibiogram, and molecular characterization of Salmonella help to control the disease in a better way through bacterin production of local isolates.

Anti-chicken type I IFN countermeasures by major avian RNA viruses.

Chicken type I interferons (type I IFNs) are key antiviral players of the chicken innate immune system and are considered potent antiviral agents against avian viral pathogens. Chicken type I IFNs are divided into three subtypes namely, chIFN-α, chIFN-ß, and chIFN-κ. Viral pathogen-associated molecular patterns (PAMPs) recognized by their corresponding specific PRRs (pattern recognition receptors) induce the expression of chicken type I IFNs. Interaction of chicken type I IFNs with their subsequent IFN receptors results in the activation of the JAK-STAT pathway, which in turn activates hundreds of chicken interferon-stimulated genes (chISGs). These chISGs establish an antiviral state in neighboring cells and prevent the replication and dissemination of viruses within chicken cells. Chicken type I IFNs activate different pathways that constitute major antiviral innate defense mechanisms in chickens. However, evolutionary mechanisms in viruses have made them resistant to these antiviral players by manipulating host innate immune pathways. This review focuses on the underlying molecular mechanisms employed by avian RNA viruses to counteract chicken type I IFNs and chISGs through different viral proteins. This may help to understand host-pathogen interactions and the development of novel therapeutic strategies to control viral infections in poultry.

Enhancement in humoral response against inactivated Newcastle disease vaccine in broiler chickens administered orally with plant-derived soyasaponin.

The present study aimed to evaluate the immunopotentiating effect of plant-derived soyasaponin and its immunogenicity in chickens challenged with Newcastle disease virus (NDV). Soyasaponin was extracted from soybean seeds and detected using the phytochemical tests, followed by quantification through the dry-weight method. One-day-old broiler chicks (n = 90) were divided into 3 groups, named as A, B, and C. Group A birds were orally administrated with soyasaponin (5 mg/kg), followed by immunization with inactivated ND vaccine intramuscularly (IM), whereas group B birds were vaccinated with inactivated ND vaccine alone. Group C birds were kept unvaccinated. A booster dose on day 21 was also administered IM to group A and B birds. At day 35, all 3 groups were challenged with NDV. To determine the immunogenicity potential of soyasaponin, antibody titer was measured using the hemagglutination inhibition test before and after the NDV challenge. Histochemical examination was performed to determine the pathological changes associated with NDV infection. Foam formation and hemolytic activity confirmed the presence of saponin in soya bean extract. Group A birds showed a higher antibody response compared with group B and C birds. The disease challenge study showed that soyasaponin-adjuvanted NDV vaccine provided complete protection to group A birds against ND. Moreover, no side effects of soyasaponin were observed on the growth performance of birds during the experiment. Therefore, we can conclude that soyasaponin is a potential immunogenic agent and therefore could be a promising candidate to launch a protective humoral response against ND in chickens.