Estimation of the genetic parameters for some of semen quality characteristics using animal models with combined phenotype and genotype data of Holstein bulls

Document Type : Research Paper

Authors

Abstract

Introduction: For the design of any successful breeding program, knowledge about semen quality traits is greatly important and per-required. Due to the critical role of bulls through artificial insemination in the genetic improvement of the dairy cattle herds, knowledge about semen characteristics and genetic factors which affect semen parameters is essential. In addition, semen with poor fertility requires more units of semen to establish a successful pregnancy and produce a live offspring. Nonetheless, both impacts are economically important factors, which are considered by the producers leading to rejection of bulls with poor semen quality, and investing mainly on highly fertile sires. Summary of previous literatures is highlighted semen traits and their key roles in upcoming fertility and pregnancy of cows within herds (Gacitua et al. 2005). Furthermore, some reports pointed DNA markers can identify the genetic background mechanism of resistance and susceptibility of sperm after freezing and thawing (Purdy et al., 2005). Additionally, previous reports supported  low hereditability scenario of semen characteristics in livestock species (England et al., 2010). Leptin is a globular protein with a tertiary structure similar to a haemopoietic cytokine synthesized by adipose tissue. It is involved in the regulation of feed intake, fetal growth, energy balance, fertility, and immune functions. The leptin molecule (16 kDa) is made up of 167 amino acids with an N-terminal secrotary signal sequence of 21 amino acids. In cattle, the leptin gene is located on the fourth chromosome. It consists of three exons and two introns. Only two exons are translated into the protein. The coding region of the leptin gene (501 nucleotides in length) is in exons 2 and 3, which are separated by an intron of approximately 2 kb. The leptin gene promoter region spans approximately 3 kb. Leptin is necessary for normal reproductive function, but when present in excess, it have detrimental effects on the male reproductive system. Human and animal studies pointed to leptin as a link between infertility and obesity, a suggestion that was corroborated by findings of low sperm count, increased sperm abnormalities, oxidative stress, and increased leptin levels in obese men. In addition, daily leptin administration to normal-weight rats has been shown to result in similar abnormalities in sperm parameters. The bovine growth hormone (bGH) is a 22 KDa single-chain polypeptide hormone, which is produced in the anterior pituitary gland. The encoding gene is approximately 1800 base pair (bp) and consists of five exons separated by four intervening sequences (Harvey et al. 2000). Recently, several studies have investigated the association between bGH locus and reproduction traits. A substitution of cytosine (C) for guanine (G) at the  position of 2141 causes an amino acid change from leucine (leu) to valine (val) at residue 127. This transversion enables the genotyping of this particular locus using the endonuclease AluI, since in the mutant bull, this enzyme does not recognize its target sequence. Several point mutations in the bovine growth hormone (GH) gene have been described, and as such, the Leu127Val polymorphism described by Lucy et al. (1993) has been extensively investigated based on  production and reproduction traits. In addition, Lechniak et al. (1999) have reported the relationship between individual semen quality traits and fertility. The purpose of the present study was to estimate the genetic parameters of some semen quality traits using animal models containing genotype of candidate gene data on Holstein bulls.
Material and methods: For this reason, 67 bulls were selected from two breeding stations in the Northwest of Iran (41 bulls) and the National Livestock Improvement Center (26 bulls), which were in the sperm production stage between 2003- 2013. In this regard, four related traits of semen quality were considered, including: volume of ejaculation, sperm concentration, live sperm percentage before freezing, and live sperm percentage after thawing. The DNA extraction was done from semen according to commercial DNA kit and quality and quantity tests were done using spectrophotometry and gel monitoring. The nucleotide polymorphisms were evaluated in two loci of the leptin gene (Exon 2 and intron 2) by the PCR-RFLP method and in the growth promoter receptor gene (promoter region) using PCR-SSR technique. Finally, using combined phenotypic and molecular information, genetic parameters were estimated through Bayesian statistics and Gibbs sampling. POPGENE software was used for molecular data and descriptive statistics (genotype frequencies, allele frequencies, and hetrozygosity index calculation). Univariate and multi variate analysis for semen characteristics was done using gibbs3f90 and renumf90 softwares.
Results and discussion: According to the molecular outputs, in all investigate genes nucleotide variation and polymorphism was observed. The results of univariate analysis of animal model for estimating heritability for traits of semen volume, sperm count, live sperm percentage before freezing, and thawing point were 0.22, 0.14, 0.20, and 0.10, respectively. Reproductive performance is controlled by the genetic make-up of dam, sire, and offspring, but it is largely affectedby environment. Thus, the reproductive efficiency of the breeding herd depends on the fertility of the bulls(Gredler et al., 2005). Bull’s fertility is also essential, since bull's DNA is the primary mechanism through which genetic improvements can efficiently be accomplished. Implementation of artificial insemination (AI) in dairy cattle production allowed improving selection of bulls for production traits. Also, frequent freezing and thawing process of bull semens significantly affected quality index and consequent evaluation of fertilization potential of a semen sample for AI in Holstein breeding stations (Mathevon  et al., 1998).However, the preselection of the samples, the high number of sperm per doses, and the high quality of the semen used in the AI programs  can reduce the variability, thereby giving a low probability of detecting fertility differences associated with seminal parameters. Spermatogenesis is a complex process that involves stem-cell renewal, genome reorganization, and genome repackaging;  so, it culminates in the production of motile gametes (Kealey et al., 2006). The process of spermatogenesis is regulated by reproductive hormones in gonadotropin axis and is controlled by a large number of genes(Sun et al., 2012). Therefore, hormone and their receptors are presumed to be good candidate genes for reproductive traits.
Conclusion: The results of this study indicated that the range of heritability values for the different semen quality characteristics are low to moderate, which may indicate that improvement of environmental factors is more effective than genetics basis.

Asadi-Khoshoei  E, Miraei-Ashtiani SR, Turkmenzehi A, Rahimi SH and Vaez Torshizi R, 2000. Evaluation of Kleiber ratio as one of criterion for selecting ram in Lori Bakhtiari sheep. Iranian Journal of  Agriculture Science 30: 649-655.
Chase CC Jr, Kirby CJ, Hammond AC, Olson TA and Lucy MC, 1998. Patterns of ovarian growth and development in cattle with a growth hormone receptor deficiency. Journal of Animal Science 76: 212-219.
Clempson AM, Pollott GE, Brickell JS, Bourne NE, Munce N and Wathes DC, 2011. Evidence that leptin genotype is associated with fertility, growth, and milk production in Holstein cows. Journal of Dairy Science 94: 3618-3628.
Druet T, Fritz  S, Sellem E, Basso B, Gerard O, Salas‐Cortes L and Eggen A, 2009. Estimation of genetic parameters and genome scan for 15 semen characteristics traits of Holstein bulls. Journal of Animal Breeding and Genetics 126: 269-277.
Ducrocq V, and P  Humblot, 1995. Genetic characteristics and evolution of semen production of young Normande bulls. Livestock Production Science 41:1–10.
England GC, Phillips L and Freeman SL, 2010. Heritability of semen characteristics in dogs. Theriogenology 74: 1136- 1140.
Foote RH, GE Seidel Jr, J Hahn, WE Berndtson and GH Coulter,  1977. Seminal quality, spermatozoal output, and testicular changes in growing Holstein bulls. Journal Dairy Science 60: 85–88.
Gacitua H and Arav A, 2005. Successful pregnancies with directional freezing of large volume buck semen. Theriogenology 63: 931-938.
Garrett AJ, Rincon G, Medrano JF, Elzo MA, Silver GA and Thomas MG, 2008. Promoter region of the bovine growth hormone receptor gene: Single nucleotide polymorphism discovery in cattle and association with performance in Brangus bulls. Journal of Animal Science 86: 3315-3323.
Gorobets GG, 1987. Heritability and variability of reproductive ability of stud bulls. Byull. Vses. Nauchno Issled. Inst. Razvedeniya Genetetic Selection’ Skokhozyaistvennykh Zhivotnykh 95: 12–13.
Gredler B, Fuerst C, Fuerst-Waltl B, Schwarzenbacher H and Sölkner, 2005. Genetic and environmental effects on semen quality of Austrian Simmental bulls. In: 56th Annual Meeting of the European Association for Animal Production, pp 5-8.‏
Hale CS, WO Herring, H Shibuya, MC Lucy, DB Lubahn, DH Keisler and GS Johnson, 2000. Decreased growth in Angus steers with a short TG-microsatellite allele in the P1 promoter of the growth hormone receptor gene. Journal Animal Science 78:2099–2104.
Houseknecht KL, AB Clifton, LM Robert and ME Spurlock, 1998. The biology of leptin. A Review Journal Animal Science 76: 1405-1420.
Kealey CG, MacNeil MD, Tess MW, Geary TW and Bellows RA, 2006. Genetic parameter estimates for scrotal circumference and semen characteristics of Line 1 Hereford bulls. Journal of Animal Science 84: 283-290.
Mathevon M, Buhr MM and Dekkers JCM, 1998. Environmental, management, and genetic factors affecting semen production in Holstein bulls. Journal of Dairy Science 81: 3321-3330.
Orangi S,‏ Ektefaie M, Atashi H, Zamiri MJ, Dadpasand M and Derakhshande A, 2015. Association of polymorphism in DGAT1 and IGF-I with productive and reproductive performance  in Holstein cows. Journal of Animal Science Researches 26: 23-32 
Purdy PH, 2006. A review on goat sperm cryopreservation. Small Ruminant Research 63(3): 215-225.
Sang L, Du QZ, Yang WC and Tang KQ, 2011. Polymorphisms in follicle stimulation hormone receptor, inhibin alpha, inhibin beta A, and prolactin genes, and their association with sperm quality in Chinese Holstein bulls. Animal Reproduction Science 126: 151-156.
SAS Guide, SAS. 2003. Version 9.1. SAS Institute Inc, Cary NC.
     Sherman EL, Nkrumah JD, Murdoch BM, Wang  CZ and Moore SS, 2008. Polymorphisms and haplotypesin the bovine neuropeptide Y, growth hormone receptor, ghrelin, insulin-like growth factor 2, and uncoupling proteins 2 and 3 genes and their associations with measures of growth, performance, feed efficiency, and carcass merit in beef cattle. Journal Animal Science 86:1–16.
Sun LP, Du, QZ, Song YP, Yu JN, Wang SJ, Sang L and Yang LG, 2012. Polymorphisms in luteinizing hormone receptor and hypothalamic gonadotropin-releasing hormone genes and their effects on sperm quality traits in Chinese Holstein bulls. Molecular Biology Reports 39: 7117-7123.‏
Taylor  JF, Bean B, Marshall CE and Sullivan JJ, 1985. Genetic and environmental components of semen production traits of artificial insemination Holstein bulls. Journal Dairy Science 68: 2703–2722.
Tokuda T, Kimura D and Fujihara T, 2001. The relationship between leptin and insulin in blood plasma of growing lambs. Journal Animal Science 73: 71-76.
Veerkamp RF, Oldenbroek JK, Van Der Gaast HJ and Van Der Werf JHJ, 2000. Genetic correlation between days until start of luteal activity and milk yield, energy balance, and live weights. Journal of Dairy Science 83: 577-583.‏
Vincent  AL, Tuggle CK, Rothschild MF, Evans G, Short TH, Southwood OI and Plastow GS, 1998. The prolactin receptor gene is associated with increased litter size in pigs. Proc. 6th World Congress Genetic Applied Livestock Production; Armidale, NSW, Australia 15–18.
Wolf  J, 2010. Heritabilities and genetic correlations for litter size and semen traits in Czech Large White and Landrace pigs. Journal Animal Science 88: 2893-2903.
Yeh  FC, and Boyle TJB 1997. Population Genetic Analysis of Co-dominant and dominant markers and Quantitative Traits. Belgian Journal of Botany 129: 157-163.
Yang WC, Tang KQ, Yu JN and Zhang CY, 2011. Effects of MboII and BspMI polymorphisms in the gonadotropin releasing hormone receptor (GnRHR) gene on sperm quality in Holstein bulls. Molecular Biology Reports 38: 3411-3415.