Performance, endoparasitary control and blood values of ewes locally adapted in semiarid region

Ferreira, Josiel; Bezerra, Ana Carla Diógenes Suassuna; Guilhermino, Magda Maria; Leite, Jacinara Hody Gurgel Morais; Silva, Wilma Emanuela da; Paiva, Renato Diógenes Macedo; Barbosa, Tallysson Nogueira; Sousa, José Ernandes Rufino de; Façanha, Débora Andréa Evangelista

doi:10.1016/j.cimid.2017.05.004

Cited by 12 publications

(5 citation statements)

References 17 publications

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“…Recent studies have shown slighter impact induced by GIN infections over this sheep breed compared with other breeds such as Dorper, Texel, Ile de France, and Santa Inês. Even in more critical categories such as females in pre and postpartum period, in which immunosuppression from nutritional and endocrine origin leads to increased infection rates, Morada Nova ewes presented lower FEC and higher PCV than the other breeds [8,9].…”

Section: Introductionmentioning

confidence: 87%

Identification of appropriate reference genes for local immune-related studies in Morada Nova sheep infected with Haemonchus contortus

et al. 2018

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Due to the great economic impact of Haemonchus contortus on sheep farming, there is an increasing number of studies addressing host resistance against this nematode, including identification of directly related immune mechanisms. In this context, relative gene expression by RT-qPCR have been largely used, due to its rapidity, high sensitivity, specificity, and reproducibility. Although, appropriate reference gene selection is crucial for accurate interpretation of results. In this study, five reference genes (GAPDH, G6PDH, YWHAZ, ACTB, and B2M) were tested for expression stability in abomasum (fundic and pyloric regions) and abomasal lymph nodes of Morada Nova sheep classified as resistant (n = 5) or susceptible (n = 5) to H. contortus infection in a flock of 151 animals. GAPDH combined with YWHAZ were selected as reference genes for abomasal fundic region and abomasal lymph nodes, whereas YWHAZ was the most stable gene for abomasal pyloric region. These genes presented the lowest intra- and inter-group variations and, consequently, highest stability. In contrast, expression of G6PDH was the least stable in all tissues. The impact of reference gene selection was demonstrated by relative quantification of a pro-inflammatory cytokine (TNFα) in abomasal fundic region. Significant differences in TNFα expression levels between resistant and susceptible groups were only observed when the most stable genes (GAPDH combined with YWHAZ) or GAPDH were used as reference genes, whereas no significant differences were observed when other tested reference genes were used. It was demonstrated that normalization of expression data using inappropriate reference genes may significantly influence interpretation results.

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Section: Introductionmentioning

confidence: 87%

Identification of appropriate reference genes for local immune-related studies in Morada Nova sheep infected with Haemonchus contortus

et al. 2018

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“…The Morada Nova, a Brazilian hair sheep breed, is well known for its improved natural resistance against GIN infections compared with other breeds such as Dorper, Texel, Ile de France, and Santa Inês [35–37]. Most of studies have compared immune profiles between sheep breeds with different levels of parasitic resistance, while studies targeting immune responses inside breeds are scarce and absent for the Morada Nova breed.…”

Section: Introductionmentioning

confidence: 99%

Innate Immune Responses Associated with Resistance againstHaemonchus contortusin Morada Nova Sheep

Toscano

Okino

Santos

et al. 2019

Journal of Immunology Research

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The immune response against Haemonchus contortus infections is primarily associated with the Th2 profile. However, the exact mechanisms associated with increased sheep resistance against this parasite remains poorly elucidated. The present study is aimed at evaluating mediators from the innate immune response in lambs of the Morada Nova Brazilian breed with contrasting H. contortus resistance phenotypes. Briefly, 287 lambs were characterized through fecal egg counts (FEC) and packed cell volume (PCV) after two independent experimental parasitic challenges with 4,000 H. contortus L3. 20 extreme resistance phenotypes (10 most resistant and 10 most susceptible) were selected, subjected to a third artificial infection with 4,000 L3, and euthanized 7 days later. Tissue samples were collected from abomasal fundic and pyloric mucosa and abomasal lymph nodes. Blood samples were collected at days 0 and 7 of the third parasitic challenge. RNA was extracted from tissue and blood samples for relative quantification of innate immune-related genes by RT-qPCR. For the abomasal fundic mucosa, increased TNFα and IL1β expression levels (P < 0.05) were found in the susceptible animals, while resistant animals had IL33 superiorly expressed (P < 0.05). Higher levels (P < 0.05) of TLR2 and CFI were found in the abomasal pyloric mucosa of resistant animals. TNFα was at higher levels (P < 0.05) in the blood of susceptible lambs, at day 0 of the third artificial infection. The exacerbated proinflammatory response observed in susceptible animals, at both local and systemic levels, may be a consequence of high H. contortus parasitism. This hypothesis is corroborated by the higher blood levels of TNFα before the onset of infection, which probably remained elevated from the previous parasitic challenges. On the other hand, resistant lambs had an enhanced response mediated by TLR recognition and complement activation. Nevertheless, this is the first study to directly associate sheep parasitic resistance with IL33, an innate trigger of the Th2-polarized response.

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“…The host resistance is measurable through performance after infection. The performance of an animal can be evaluated through productive characteristics, the clinical condition observed, immunological responses and variables directly related to parasite presence, such as fecal egg count (Ferreira et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Phenotypical categorization of indigenous ewes as resistant, resilient or susceptible to Haemonchus contortus

David

Costa

Aylton

et al. 2022

An. Acad. Bras. Ciênc.

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The economic losses caused by parasite infections, aggravated by resistance to anthelmintics, have generated demand for alternatives involving non-chemical control, such as the selection of resistant animals. The objective of this study was to identify which characteristics best describe animals that are resistant, resilient or susceptible to Haemonchus contortus and estimate the percent number in each category. Sixty-one Morada Nova ewes were evaluated in an extensive system. The performance variables (weight, body condition score), hematological variables (packed cell volume, hemoglobin, white blood cells, segmented neutrophils, lymphocytes, eosinophils, monocytes) and fecal egg counts were measured individually every 14 days during 6 months. The variables were transformed, and analysis of variance was carried out, with construction of a correlation network. Characteristics linked to parasite infection showed variations among the categories, which helped to identify sheep resistant, resilient or susceptible to H. contortus. Based on the analyses performed, 88.3% of the animals were resistant or resilient and only 11.7% were susceptible. Presence of Trichostrongylidae eggs, body condition score, packed cell volume (PCV) and eosinophil counts were found to be good indicators of naturally infected ewes, and there were significant differences between the categories and correlations between the traits.

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Performance, endoparasitary control and blood values of ewes locally adapted in semiarid region

Cited by 12 publications

References 17 publications

Identification of appropriate reference genes for local immune-related studies in Morada Nova sheep infected with Haemonchus contortus

Identification of appropriate reference genes for local immune-related studies in Morada Nova sheep infected with Haemonchus contortus

Innate Immune Responses Associated with Resistance againstHaemonchus contortusin Morada Nova Sheep

Phenotypical categorization of indigenous ewes as resistant, resilient or susceptible to Haemonchus contortus

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