Polymorphisms in TLR4 Gene Associated With Somatic Cell Score in Water Buffaloes (Bubalus bubalis).

Valentina Roldan-Montes,Humberto Tonhati,Lucia Galvão Albuquerque,Gregório Miguel Ferreira De Camargo,Naudin Alejandro Hurtado-Lugo,Ana Cláudia De Freitas,Daiane Cristina Becker Scalez,André Vieira Do Nascimento,Diercles Francisco Cardoso,Ana Cristina Herrera,Daniel Jordan De Abreu Santos

doi:10.3389/fvets.2020.568249

Abstract

Considering the importance of the diseases affecting the productive performance of animals in the dairy industry worldwide, it is necessary to implement tools that help to control and limit the occurrence of such diseases. As the increased somatic cell counts (SCC) are a direct expression of the inflammatory process, they are candidates to become the usual parameter for assessing udder health regarding milk quality and for monitoring mastitis incidences. Toll-Like Receptors are membrane proteins that play a key role in immunity, recognizing pathogens and, subsequently, activating immune responses. The present study was conducted to identify single nucleotide polymorphisms in the TLR4 gene of buffaloes and to analyze its associations with somatic cell counts. DNA samples of 120 Murrah buffaloes were used. The whole coding region of the TLR4 gene was amplified by polymerase chain reaction reactions and sequenced for polymorphism scanning. A total of 13 polymorphisms were identified for the sequenced regions of the TLR4, most of which are in the coding region. The association with the somatic cell score was highly significant (p < 0.001) for all identified polymorphisms of TLR4 gene (g.54621T>A, g.54429G>T, g.54407T>A, g.46616C>A, g.46613T>G, g.46612A>G, g.46611C>A, g.46609T>G, g.46541C>G, g.46526C>A, g.46516T>C, g.46376C>T, g.46372T>C). Therefore, it is suggested that the markers of the TLR4 gene can be used as molecular markers for mastitis resistance in buffaloes, due to their association with somatic cell counts.

Highlights

The water buffalo (Bubalus bubalis) is a worldwide species used as a source of draft power, milk, and meat [1]
The comprehension of genomic regions and genes underlying the genetic variation in somatic cell counts (SCC) of buffaloes might be useful for the assessment of genetic variability of mastitis resistance in the species, and it may assist the early selection of more robust animals
The following statistical model was applied: yijkl = μ + CGi + b1IVj + b2IVj2 + Ml + Tk + eijkl where, yijkl is the SCC determined for the ijklth animal; μ is the average of the SCC in the population; CGi is the fixed effect of ith contemporary group; IVj is the age of the jth dam at birth, considered as a linear and quadraticvariable in the model; Mlis the fixed effect of the lth genotype for each polymorphism detected in the Toll-like receptor 4 (TLR4) gene; Tk is the random effect of the sire, and eijkl is the residual random effect associated with the observation yijkl

Summary

INTRODUCTION

The water buffalo (Bubalus bubalis) is a worldwide species used as a source of draft power, milk, and meat [1]. The comprehension of genomic regions and genes underlying the genetic variation in SCC of buffaloes might be useful for the assessment of genetic variability of mastitis resistance in the species, and it may assist the early selection of more robust animals. It is a pivotal first step for a better understanding of biological mechanisms behind the mastitis resistance and interpretation of the relation between clinical and subclinical mastitis, which are mostly associated with the activation of the innate and adaptive immune system, respectively [15]. We contrast the predicted protein structure of the TLR4 gene of buffaloes and cattle

MATERIALS AND METHODS

RESULTS AND DISCUSSION

ETHICS STATEMENT