Analiza povezanosti polimorfizma gena za laktoferin (LTF) sa zdravljem mlečne žlezde i proizvodnim karakteristikama krava holštajn-frizijske rase
Analysis of association lactofferin (LTF) gene polymorphism with mammary gland health and production characteristics of Holstein-Friesian cows
Author
Maletić, Milan M.
Mentor
Stanimirović, Zoran
Committee members
Vakanjac, Slobodanka
Katić, Vera
Pavlović, Miloš

Boboš, Stanko
Metadata
Show full item recordAbstract
Brzi razvoj molekularne genetike tokom posledenje tri decenije omogućio je
direktnu analizu genoma životinja, proučavanje strukture i funkcije gena, pa samim tim
pomogao boljem razumevanju delovanja nasledne osnove. Molekularno-genetičke
metode omogućile su uvid u nekodirajuće delove genoma, koje kod sisara čine više od
90%. DNK (dezoksiribonukleinska kiselina) zapisa. U slučаjevimа gde se prаte osobine
koje su generаlno sа niskim heritibilitetom, kаo što je slučаj sа otpornošću nа mаstitis,
MAS (mаrker аsistirаnа selekcijа) ili genomskа selekcijа pokаzаle su bolji rezultаt u
odnosu nа konvencionаlni metod selekcije. Primаrni cilj u ispitivаnju kаndidаt-genа
povezаnih sа pojаvljivаnjem mаstitisа je identifikаcijа genа koji su uključeni u proces
imunog odgovorа mlečne žlezde. Laktoferin gen (LTF) se u većem broju istraživanja
pominje kao validni molekularni marker u praćenju procesa otpornosti mlečne žlezde
prema infekciji. Cilj ovog rada bio je ispitivanje polimorfizma gena za LTF i nj...egov
uticaj na zdravstveni status mlečne žlezde i proizvodne karakteristike krava holštajnfrizijske
rase u Srbiji. Ogled je obuhvatao 100 krava različite laktacione starosti (1.-4.
laktacija) na farmi blizu Beograda. Životinje su bile ravnomerno raspoređene u grupama
po laktacionoj starosti (χ2=0,578; p=0,902). Posle ekstrakcije DNK iz krvi amplifikovan
je fragment gena za laktoferin na intronu 6 metodom PCR (polymerase chain reactionreakcija
lančane polimeraze). Pomoću specifičnih prajmera, identifikovana su dva
genotipa AA i AB od moguća tri, (BB nije identifikovan) metodom PCR-RFLP
(Restriction Fragment Lenght Polymorphism-polimorfizam u dužini restrikcionih
fragmenata). U cilju ispitivanja zdravstvenog statusa mlečne žlezde, kvalitativnog
sastava i ukupne proizvodnje mleka, svakog meseca kroz period standardne laktacije od
305 dana, su uzimani uzorci mleka. Broj somatskih ćelija (SCC) određivan je
mikroskopski a koncentracija proteina i mlečne masti utvrđivana je spektrofotometrijski
(aparat Milkoscan). U zajedničkom uzorku od 90 krava, konstatovana je statistički vrlo
značajno veća (χ2=40,894; p<0,001) zastupljenost genotipa AA ( 74 ili 82,22%) u
odnosu na zastupljenost genotipa AB ( 16 ili17,78%). Prema Hardy-Weinberg jednačini
odnos genotipova AA, AB i BB se nalazi u ravnoteži (p=0,3547). Distribucija A alela u
posmatranoj populaciji bila je 91,11% a B alela 8,89%. Ovako visok broj homozigota
ukazuje na smanjeni protok gena u populaciji i veći stepen genetske konzervisanosti
zapata. Poizvodne karakteristike praćenih genotipova nisu se statistički razlikovale...
The rapid development of molecular genetics during last three decades has facilitate the
direct analysis of the genome of animals and insight in gene structure and function, and
thus helped to a better understanding basis of genetic inheritance. Molecular-genetic
methods enabled access to the non-coding parts of the genome, which in mammals
make up more than 90% DNA (deoxyribonucleic acid). MAS (marker assisted
selection) or genomic selection showed a better result compared to the conventional
method of selection when generally low heritability traits are followed, as is the case
with resistance to mastitis. The primary objective in tests concerning appearance of
mastitis is the identification of candidate genes that are involved in the immune
response of the mammary gland. Lactoferin gene (LTF) is proved by many studies as a
valid molecular marker in monitoring the process of resistance to infection of the
mammary gland. The aim of this study was to investigate the polymorphism of LTF...
gene and its impact on the health status of the mammary gland and production
characteristics of Holstein-Friesian breed in Serbia. The experiment included 100 cows
of different lactation age (1.-4. lactation) on a farm near Belgrade. Due to some health
issues that are not directly related to the research 10 cows were excluded. The animals
were equally distributed in groups by lactation age (χ2 = 0.578; p = 0.902). DNA was
extracted from the blood and intron 6 from lactoferrin gene was amplified by PCR
(polymerase chain reaction). Using specific primers, two genotypes AA and AB of the
three possible (BB was not found) were identified by PCR-RFLP (PCR-Restriction
Fragment Length Polymorphism). In order to examine the health status of the mammary
gland and qualitative composition of the total milk production, each month through
standard lactation period of 305 days samples were taken from the milk. Somatic cell
count (SCC) was determined microscopically and the concentration of protein and fat in
milk was determined by spectrophotometry (MilkoScan). The pooled sample of 90
cows showed statistically significant (χ2 = 40.894; p <0.001) representation of the
genotype AA (74 or 82.22%) compared to the prevalence of genotype AB (16 or 17.78
%). All genotypes (AA, AB and BB) were in the Hardy-Weinberg equilibrium (P =
0.3547). Distribution of A and B alleles in the observed population were 91.11% and
8.89%, respectively. This high number of homozygotes indicates reduced gene flow in
the examined population and a higher degree of genetic conservation...