Novel formulation with essential oils as a potential agent to minimize African swine fever virus transmission in an in vivo trial in swine

Research (Published online: 20-07-2021)

19. Novel formulation with essential oils as a potential agent to minimize African swine fever virus transmission in an in vivo trial in swine

Haig Yousef Babikian, Rajeev Kumar Jha, Quang Lam Truong, Lan Thi Nguyen, Yusef Babikyan, Hoa Thi Nguyen, Thanh Long To and Ali Agus

Veterinary World, 14(7): 1853-1866

ABSTRACT

Background and Aim: African swine fever (ASF) is currently the most prevalent disease in swine. The disease is spreading throughout primary swine-producing countries with heavy losses in population and revenue. To date, no successful vaccines or medications have been reported. This study aimed to design and develop a blend of natural essential oils and test its efficacy against the ASF virus (ASFV) in swine.

Materials and Methods: We attempted to develop a natural oil blend formulation (NOBF) and determine its efficacy against the ASFV. This study follows on from a previously published in vitro study that reported that the NOBF has anti ASFV properties. A study was designed using 21 healthy piglets of triple-cross (Landrace + Yorkshire + Durok) crossbred pathogen-free pigs with an average weight of 15 kg. The study consisted of NOBF-incubated, NOBF, positive control, and negative control groups. The NOBF groups were administered NOBF (80 mL/ton mixed in drinking water) beginning 10 days before the challenge and continuing throughout the experiment. The positive and negative control pigs consumed regular drinking water. The pigs were challenged by a sublethal dose of pure isolate ASFV strain Vietnam National University of Agriculture-ASFV-L01/HN/04/19 inoculation with 103.5 HAD50/dose through the intramuscular route. There were sic pigs in each group, three pigs directly IM challenged, and three pigs were considered cohoused pigs.

Results: Both challenged (three) and cohoused (three) pigs in the positive control showed clinical signs of ASFV infection, as detected by real-time polymerase chain reaction (RT-PCR) in blood samples, oral swabs, and feces. There was 100% cumulative mortality, that is, both challenged and contact pigs died in the positive control group on day 20 of infection. No signs of infection or mortality were observed in the NOBF-incubated group. The challenged pigs in the NOBF-direct challenge group showed clinical signs and mortality, whereas no clinical signs or symptoms occurred in the cohoused pigs. The immunoglobulin G (IgG) level of the contact pigs was the highest in the treatment group and the lowest in the positive control group. The IgM level of the contact pigs in the treatment groups was the lowest, whereas that of the positive control was the highest. The RT-PCR test showed that the ASFV was deactivated in the NOBF-incubated group. The challenged and contact pigs of the positive control group had high Ct values. The challenged pigs of the NOBF group had high Ct values, whereas the contact pigs from the same group and those of the negative control were negative for the ASFV, determined by PCR, in all samples. The comparison of the challenged groups showed that the appearance of the virus was delayed by at least 2 days in the NOBF group compared to the positive control group.

Conclusion: The results showed that NOBF can prevent the spread of the ASFV in a population. Moreover, NOBF can enhance the pig humoral immune system by enhancing IgG levels and reducing IgM levels. This study successfully demonstrated that NOBF is an anti-ASFV agent, which prevents horizontal transmission and enhances pig humoral immunity.

Keywords: African swine fever virus, In vivo trials, intramuscular challenge, natural oil blend formulation, Swine.

Development of lymphocyte subpopulations in local breed chickens

Research (Published online: 19-07-2021)

18. Development of lymphocyte subpopulations in local breed chickens

Adil Sabr Al-Ogaili and Samer Sadeq Hameed

Veterinary World, 14(7): 1846-1852

ABSTRACT

Background and Aim: Local breeds of chicken are known to have relatively higher disease resistance to many endemic diseases and diseases that are highly virulent in commercial chickens. This study aimed to address the lymphocyte subpopulations in three constitutive immune system organs (thymus, bursa of Fabricius, and spleen) in 30, 8-week-old, male local breed chickens.

Materials and Methods: The T (CD3+) and B lymphocytes (Bu-1+) were identified through one-color, direct immunofluorescent staining of the thymus, bursa, and spleen lymphocytes. Likewise, two-color, direct immunofluorescent staining was performed to identify the CD4- and/or CD8-defined T lymphocytes. The proportions of T and B lymphocytes and CD4- and/or CD8 defined chicken lymphocyte subsets in lymphoid suspensions prepared from the thymus, bursa, and spleen were determined by flow cytometry.

Results: CD3+ cells, particularly those positive for CD4+CD8–, were dominant in the thymus, whereas cells expressing the Bu-1 marker were predominant in the bursa of Fabricius. The proportion of T and B cells was almost equal in the spleen, with more cells expressing the CD4–CD8+ marker in the red pulp.

Conclusion: These findings indicate that local breeds of chicken could serve as a reliable model for studying the immune system of commercial light chicken breeds, due to the similarity in the presence and the distribution of the immune cells.

Keywords: direct immunofluorescent staining, flow cytometry, local breed chickens, lymphocytes subpopulations.

Detection of African swine fever virus in pigs in Southwest Nigeria

Research (Published online: 19-07-2021)

17. Detection of African swine fever virus in pigs in Southwest Nigeria

Emmanuel Jolaoluwa Awosanya, Babasola Oluseyi Olugasa, Fufa Ido Gimba, Mohd Yusoff Sabri and Gabriel Adetunji Ogundipe

Veterinary World, 14(7): 1840-1845

ABSTRACT

Background and Aim: Nigeria experienced repeated outbreaks of African swine fever (ASF) in pig herds between 1997 and 2005 in the southwest region of the country. ASF is believed to currently be enzootic in this region. The status of enzootic transmission of ASF virus strain to pigs is; however, unknown. Twenty-three genotypes of the ASF virus based on the p72 gene are found across Africa. This study aimed to identify the current circulating field strain(s) of the ASF virus in Southwest Nigeria and characterized evolutionary trends.

Materials and Methods: DNA samples were extracted from 144 pooled blood samples obtained from 2012 to 2013 following the manufacturer's instructions. DNA was used for conventional polymerase chain reaction using primers targeting the p72 gene and amplified products sequenced with Sanger's sequencing. Sequences were analyzed for homology and phylogenetic relationships.

Results: Eleven of 144 samples (7.6%) showed bands at 950 bp. A new field strain of ASF virus of genotype I that shared ancestry with ASF virus strains or isolates from Spain and Brazil was identified among pig herds. The new strain differs phylogenetically in amino acid composition compared with previously identified ASF virus field strains.

Conclusion: The currently circulating field strain of ASF virus suggests a mutation responsible for decreased morbidity and mortality recorded in sporadic cases.

Keywords: African swine fever virus, enzootic, evolution, phylogeny, sequencing, Southwest Nigeria.

Risk factors associated with dystocia in swine

Research (Published online: 16-07-2021)

16. Risk factors associated with dystocia in swine

Nguyen Hoai Nam and Peerapol Sukon

Veterinary World, 14(7): 1835-1839

ABSTRACT

Background and Aim: Dystocia in swine can increase the stillbirth rate; however, its importance in pig-breeding systems has been underestimated. Until now, few studies have investigated dystocia and associated risk factors. Therefore, in this study, we aimed to evaluate the effects of various risk factors on dystocia in swine.

Materials and Methods: Out of 5,557 piglets, we included 4,997 piglets in risk analysis study. The dependent variable was dystocia, which was recorded when a birth interval exceeded 45 min or when obstetric assistance was applied. The independent variables were parity, gestation length, litter size, birth order, gender, presence of a dead piglet, birthweight, crown rump length, body mass index, ponderal index, and oxytocin use. We used generalized linear mixed models to examine the associations between potential risk factors and dystocia at the piglet level.

Results: A total of 6% of the piglets were born with a dystocia event, and 47.2% of the farrowing experienced at least one event. Dead piglets and piglets with a crown rump length of >31 cm were associated with an increased dystocia rate. This rate decreased from birth order 2 to 7, stabilized to 11, and then increased till the end of the fetal expulsion process.

Conclusion: Dystocia is common in swine. Therefore, this condition should be carefully addressed by veterinarians and farrowing house personnel so that its adverse effect on welfare and productivity of sows and survivability of piglets can be reduced. Further studies investigating dystocia status and risk factors in different swine farrowing systems should be undertaken to provide more knowledge about this neglected condition.

Keywords: birth order, crown rump length, dystocia, piglet, swine.

Non-infectious risk factors for intrapartum stillbirth in a swine farm in the North of Vietnam

Research (Published online: 16-07-2021)

15. Non-infectious risk factors for intrapartum stillbirth in a swine farm in the North of Vietnam

Nguyen Hoai Nam and Peerapol Sukon

Veterinary World, 14(7): 1829-1834

ABSTRACT

Background and Aim: Stillbirth causes considerable loss to the pig farming industry. Methods aimed at reducing stillbirth should base on the understanding of risk factors for intrapartum stillbirth because it accounts for 75% of all stillbirths. Unfortunately, few studies have differentiated between intrapartum and prepartum stillbirths leading to inadequate information about risk factors for sole intrapartum stillbirth. This study investigated risk factors for piglet's intrapartum stillbirth.

Materials and Methods: Data of 1527 piglets born from 103 sows in one herd were recorded. Generalized linear mixed models were used to determine the relationship between investigated risk factors and intrapartum stillbirth at the piglet level. The potential risk factors were parity, gestation length (GL), litter size (LS), birth order (BO), birth interval (BI), cumulative farrowing duration (CFD), gender, crown-rump length, birth weight (BW), body mass index, ponderal index (PI), and BW deviation.

Results: About 60% (60.2%, 62/103) litters had stillborn piglet(s), and the intrapartum stillbirth rate was 5.8% (89/1527). BW deviation (≤0.1 and >0.6 kg), LS >13, GL (<114 and >117 days), PI ≤54, and BO >10 were the most significant factors associated with increased intrapartum stillbirth. No effect of parity, sex, BI, and CFD on intrapartum stillbirth was detected.

Conclusion: These data stressed the importance of piglets' size and shape in the prediction of intrapartum stillbirth. Furthermore, large LS, high BO, short, and long GL were associated with increased intrapartum stillbirth. The results of this study suggest that procedures aimed at increasing litter homogeneity, optimizing piglets' size and shape, avoiding short and long gestation, and increasing supervision rate, especially at the second half, of the farrowing may reduce piglet's intrapartum stillbirth.

Keywords: birth weight deviation, intrapartum stillbirth, piglet, postmortem examination.

Spondias pinnata bark extract- an ameliorator of inflammatory derangement in etoposide induced mucositis: An experimental approach

Research (Published online: 15-07-2021)

14. Spondias pinnata bark extract- an ameliorator of inflammatory derangement in etoposide induced mucositis: An experimental approach

Aradhana Marathe, Gayathri M. Rao and M. Chakrapani

Veterinary World, 14(7): 1822-1828

ABSTRACT

Background and Aim: Mucositis, one of the vulnerabilities of chemotherapy, affects the physiological activities and therapeutic strategies of patients because it can affect the normal cell population. Etoposide is a commonly used chemotherapeutic agent for cancers such as oral, lung, and gastrointestinal. In addition to the abnormal metabolic processes in the body caused by tumorigenesis, new metabolic alterations can occur, such as oxidative stress, antioxidant imbalance, and inflammatory reactions, all of which can contribute to existing patient vulnerability. Therapeutic adjuvants can help overcome these toxic effects. Spondias pinnata is a tropical tree omnipresent in the coastal and Western Ghat section of India that is used for culinary purposes and as a local analgesic. Therefore, we aimed to study the anti-inflammatory effects of S. pinnata in an etoposide-induced mucositis rat model.

Materials and Methods: Small intestinal tissue homogenates from albino Wistar rats were used to estimate the levels of glutathione (GSH) and nitric oxide (NO), and activities of total antioxidant (TAO), myeloperoxidase (MPO) and Na+-K+ ATPase. The animals were grouped into: (1) normal control, (2) etoposide-induced mucositis (65 mg/kg bodyweight, single IP dose), (3) S. pinnata control group, and (4) etoposide followed by S. pinnata bark extract (200 mg/kg bodyweight, once in a day). Animals were sacrificed after 24, 48, 72, and 96 h and compared with that of the normal control group (n=6). Statistical analysis was performed using EZR software.

Results: We observed a significant decrease in the TAO and GSH levels with a marked increase in NO, MPO, and Na+-K+ ATPase activity in the mucositis group. A tendency to recover from the decreased TAO and GSH levels existed in the treated group, showing the protective effects of S. pinnata bark extract against mucositis. In addition, this extract also showed anti-inflammatory effects as reflected by the recovery in MPO levels at the end of 96 h. Maintenance of Na+-K+ ATPase activity in the treated group demonstrates the protective effects of the extract against the increased levels observed in the etoposide-induced mucositis group.

Conclusion: This study revealed the protective effects of S. pinnata bark extract against the oxidative and inflammatory changes that occurred during the development of mucositis. This would decrease the pathological burden during chemotherapy and prevent any hurdles in therapeutic modalities.

Keywords: etoposide, mucositis, oxidative and inflammatory markers.

Application of equine herpesvirus-1 vaccine inactivated by both formaldehyde and binary ethylenimine in equine

Research (Published online: 15-07-2021)

13. Application of equine herpesvirus-1 vaccine inactivated by both formaldehyde and binary ethylenimine in equine

Fatma F. Warda, Hala El Sawy Ahmed, Nermeen G. Shafik, Christine A. Mikhael, Heba M. G. Abd-ElAziz, Walaa A. Mohammed and Eman A. Shosha

Veterinary World, 14(7): 1815-1821

ABSTRACT

Background and Aim: Equine herpesvirus-1 infection in horses causes a wide range of manifestations affecting the respiratory tract. The virus can cause serious economic losses through sporadic abortion in pregnant mares, perinatal death, respiratory disease in young foals. This study was designed to prepare inactivated equine herpesvirus-1 (EHV-1) vaccine using both 0.005 M binary ethylenimine (BEI) and 0.0006% formaldehyde (FA) to decrease the use of BEI and provide a good immunological response. The efficacy, safety, and duration of immunity of the prepared inactivated EHV-1 vaccine were evaluated.

Materials and Methods: The prepared FA/BEI-inactivated EHV-1 vaccine was adjuvanted with Alhydrogel and then evaluated by inoculation into guinea pigs, followed by comparison with the commercial inactivated EHV-1 vaccine. These two vaccines were evaluated by testing the safety and immunogenicity in horses classified into two groups. Group A was vaccinated with two doses of the prepared vaccine at a 4-week interval, while Group B was vaccinated with two doses of the commercial vaccine only. Anti-EHV-1 antibodies were detected in horse serum using enzyme-linked immunosorbent assay (ELISA) and virus neutralizing test (VNT).

Results: Regarding the time required to inactivate EHV-1 vaccine, this was decreased using 0.005 M BEI and 0.0006% FA from 24 to 8 h. ELISA in Group A horses demonstrated a significant increase in EHV-1 antibody titer at 2 weeks after the booster dose compared with that for the pre-booster one, from 485 to 855 antibody titer, which then peaked at 1240 in the 3rd month post-vaccination; after that, it began to decline gradually until the 6th month. Meanwhile, in Group B, the ELISA reading increased from 420 to 790 and then peaked at 1215. The VNT mean in Group A increased from 1.1 to 2.5 within 2 weeks after administration of the booster dose, while in Group B it increased from 0.8 to 2.1. Moreover, ELISA in Group A pigs indicated mean antibody titers at the 3rd week post-inoculation of 576 for Group A and 554 for Group B.

Conclusion: The inactivated EHV-1 vaccine, with fewer chemicals, was prepared in a shorter time. It is safe and also more potent to protect horses for up to 6 months against EHV-1 infection than the commercially produced vaccine.

Keywords: binary ethylene imine, equine herpesvirus-1, formaldehyde, immunogenicity, inactivated vaccine.