POLYMORPHISM OF PROLACTIN AND SOMATOTROPIN GENES IN DAIRY CATTLE OF THE REPUBLIC OF TATARSTAN

Изучен полиморфизм и определена частота встречаемости аллельных вариантов по генам пролактина (PRL) и соматотропина (GH) у коров в условиях двух племенных хозяйств Республики Татарстан. Объектом исследования были животные черно-пестрой породы первого (n=151) и третьего (n=168) отелов и холмогорской породы первого (n=160) и третьего (n=143) отелов. Проведено генотипирование коров по генам PRL и GH методом ДНК-диагностики. Установлено, что среди молочного скота преимущественно встречаются особи с генотипом PRL АА (70,0—77,5%), с частотой аллеля А гена пролактина — 0,83—0,87, аллеля В — 0,13—0,17. Встречаемость аллеля В была выше среди холмогорских коров (0,16—0,17). В стаде полновозрастных животных черно-пестрой породы имеется сдвиг генетического равновесия в сторону генотипов PRL AA и PRL BB (χ2=3,97; Р<0,05). В исследуемых стадах крупного рогатого скота выражено преимущество генотипа GH LL с частотой встречаемости 51,0—79,2%. Встречаемость генотипа GH VV у черно-пестрого скота составила 2,0—2,4%, у холмогорского — 5,6—7,0%. Аллель L гена соматотропина преобладает над аллелем V в обеих породах. При этом чаще встречаемость аллеля L GH среди коров холмогорской породы (0,28—0,29). У холмогорских коров больше представлены редкие и желательные аллели генов PRL и GH. Чтобы повысить встречаемость «предпочтительных» в хозяйственном отношении генотипов и аллелей ДНК-маркеров, необходимо в большей степени использовать быков-производителей с желательными аллелями PRL и GH, а именно В и V соответственно. The polymorphism was studied and the frequency of occurrence of allelic variants for the genes of prolactin (PRL) and somatotropin (GH) was determinedin cows in two bred livestock farms of the Republic of Tatarstan. The object of the study were animals of the black-and-white breed of the first (n=151) and third (n=168) calving and the Kholmogory breed of the first (n=160) and third (n=143) calving. Genotyping of cows for PRL and GH genes was carried out using method of DNA diagnostics. It was revealed that there were mainly individuals with the PRL AA genotype (70,0–77,5%)among dairy cattle, the frequency of the A allele of the prolactin gene was 0,83–0,87, the B allele was 0,13–0,17. The frequency of allele B was higher among Kholmogory cows (0,16–0,17). There was a shift in the genetic balance towards the PRL AA and PRL BB genotypes (χ2=3,97; Р<0,05) in the herd of full-age animals of the black-and-white breed. The advantage of the GH LL genotype was expressed with a frequency of occurrence 51,0–79,2% in the studied cattle herds. The occurence of the GH VV genotype was 2,0–2,4%in black-and-white cattle, 5,6–7,0% was in Kholmogorycattle. The L allele of the somatotropin gene predominated over the V allele in both breeds. Moreover, the occurrence of the L GH allele among cows of the Kholmogory breed (0,28–0,29) was more often. Rare and desirable alleles of the PRL and GH genes are more represented in Kholmogory cows. In order to increase the occurrence of economically “preferred” genotypes and alleles of DNA markers, it is necessary to use more stud bulls with the desired PRL and GH alleles, namely B and V, respectively.

Study association of bPRL (Bovine Prolactin) gene and milk production trait in Indonesian Holstein dairy cattle

This study was aimed to analyze the genetic variation of bPRL (Bovine Prolactin) gene and its association to milk production in Indonesian Friesian Holstein (IFH) dairy cattle. In total 49 DNA from whole blood were extracted and followed with PCR-RFLP to distinguish the genotype difference between individual samples. The fragment of bPRL gene was amplified using pair of primer forward 5’-GAGTCCTTATGAGCTTGATTCTT-3’ and reverse 5’-GCCTTCCAGAAGTCGTTTGTTTTC-3’, resulting in 156 bp PCR product size. DNA digestion then performed using RsaI restriction enzyme that recognizes 5’-GT↓AC-3’ sites with blunt-end termini. According to the study, two genotypes were discovered that are AA and AB, with respective frequencies of 0.84 and 0.16. Based on the genotype grouping of milk production data, AB genotype yielded 4016.63±1344 kg while AA genotype yielded 3314.32±1153 Kg of milk per lactation. However, there is no statistical (P>0,05) difference between both genotypes on the amount of milk yielded. It is concluded that bPRL gene was not associated with milk production traits in the studied Indonesian Dairy Cattle population.

Characterization of 24bp Insertion Polymorphism of Prolactin Gene and its Association with Quantitative Traits in Tellicherry Native Chicken Breed

Background: Over many centuries, the conventional methods of poultry breeding is based on the phenotypic selection of the birds with superior trait in a particular population. Prolactin is a physiological candidate gene that has significant effects on production traits in poultry. The objective of this study was to investigate 24bp insertion (I) polymorphism of prolactin gene and its association with quantitative traits in Tellicherry native chicken. Methods: A total of 200 blood samples were collected from the randomly selected birds of All India Co-ordinated Research Project (AICRP) on Poultry Breeding, Mannuthy. The isolated DNA samples were subjected to polymerase chain reaction (PCR) by using specific set of primers to amplify the 24bp insertion polymorphism. PCR amplicons were sequenced to study the polymorphism at nucleotide level. Result: PCR amplification revealed the presence of a specific DNA fragment with 130/154bp contained 24bp insertion polymorphism. Based on the polymorphic patterns birds were designated with three genotypes as II, ID and DD. The frequency of I (0.6975) allele was found higher than D (0.3025) allele. Our experimental results revealed that 24bp insertion polymorphism of prolactin did not have a significant association with production traits viz, age at sexual maturity, egg weight and egg number in Tellicherry native chicken.

Impact of Nano-Bromocriptine on Egg Production Performance and Prolactin Expression in Layers

The current study aimed to investigate the potential use of nano-bromocriptine in improving the laying performance of late laying hens by modulating the prolactin gene expression. A total of 150 NOVOgen brown laying hens aged 70 weeks were randomly allocated into three groups of 50 birds each. The first group was kept as a control, while the second and the third groups were treated with bromocriptine and nano-bromocriptine, respectively, at a dose of 100 µg/kg body weight per week. The pause days, egg production, feed per dozen egg, and Haugh unit were determined on a monthly basis. Also, the relative prolactin gene expression in the pituitary gland was quantified using qPCR and the number of the ovarian follicles was determined after slaughtering at the 84th week of age. It was found that nano-bromocriptine and bromocriptine improved egg laying performance with minimal pause days, reduced feed per dozen egg, and depressed the relative prolactin gene expression; however, nano-bromocriptine treatment was significantly effective compared to bromocriptine. In conclusion, nano-bromocriptine might be beneficial for elongating sequences and reducing pauses.

PCR-RFLP Analysis of Single Nucleotide Polymorphism (SNP) C-2402T at the Promoter Region of Prolactin Gene and its Association with Positively Correlated Production Traits in White Leghorn Chicken

Background: The avian prolactin gene is highly conserved, located on chromosome number 2 and most sequence polymorphisms occurs in the 5’ flanking region, 3’ flanking region, and the coding region of signal peptide. The present study was aimed at the identification of SNP C-2402T of prolactin gene and its association with production traits in White Leghorn chicken. Methods: A total of 200 birds of White Leghorn were selected from All India Co-ordinated Research Project on Poultry improvement (AICRP) farm, Mannuthy. Genomic DNA was isolated from venous blood. Polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) analysis was done to identify the SNP C-2402T of prolactin gene. Result: All the birds were observed with the same genotype CC and the frequency of the C allele was one.

Heritabilitas Produki Telur Ayam Lokal Papua Berbeda Genotip dari Lokus 24- bp Insertion-Deletion dalam Promotor Gen Prolaktin

The heritability (h2) of a trait shows phenotypes variance of the trait caused by additive genetic variance. The h2 value is used to estimate the quantitative trait breeding value of livestock in order to improve these traits through selection. This study aims to estimate the h2 of egg production characteristics in Papua local chickens with different genotypes from the 24-bp InDel (Insertion-Deletion) locus in the prolactin gene promoter region (24-bp InDel/cPRLp locus). A total of 13 pairs of Papua local chickens consisting of 3 pairs of II genotypes (♂II x ♀II) and 11 female offspring, 5 pairs of ID genotypes (♂ID x ♂ID) and 19 female offspring, and 5 pairs of DD genotypes (DD x ♀DD) and 17 female offspring were used in this study. Observations were made on the characteristics of egg production in female offspring of each genotype group. The variance component for h2 estimation is obtained by the one-way analysis of variance method and the separation of the variance components for single pairs. The results showed that the h2 at first laying of eggs in all genotype groups was moderate (0.10 to 0.30); the h2 of the number of eggs produced from the time they first laid eggs until the age of 240 days in II and ID genotype groups was high (> 0.3), while in the DD genotype group was classified as moderate (0.10 to 0.30); and the h2 of egg weight in all genotype groups was moderate (0.10 to 0.30). The high h2 of a trait indicates that the trait is more dominated by additive genes and is more responsive to the selection treatment.

​Identification of Single Nucleotide Polymorphism (SNP) C-2161G in the Promoter Region of Prolactin Gene and its Association with Egg Production in Tellicherry Native Chicken

Background: Prolactin is a physiological candidate gene which has significant effects on egg production in poultry. Also, it plays a major role on incubation behaviour (broodiness) in birds. The main objective of the present study was identification of single nucleotide polymorphism (SNP) C-2161G in the promoter region of prolactin gene and its association with egg production in Tellicherry native chicken population. Methods: A total of 200 blood samples were collected from the randomly selected birds of Tellicherry native chicken in All India Co-ordinated Research Project on Poultry improvement (AICRP) farm, Mannuthy, Thrissur, Kerala. Isolation of Genomic DNA was done and the isolated samples were subjected to polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) analysis to identify the SNP C-2161G of prolactin gene. Result: On the basis of RFLP patterns, birds were designated with three different genotypes namely CC, CG and GG. The allelic and genotypic frequency was calculated. The observed genotypic frequency at the SNP site C-2161G was CC (0.61), CG (0.160) and GG (0.23) and the frequency of allele was 0.69 for C and 0.31 for G. The egg production was shown to be statistically similar for the genotypes of SNP C-2161G.

Genetic Polymorphism in Prolactin Gene and its Effect on Test Day Milk Production Traits in Sahiwal Cattle

Background: The selection of genetically superior animals at an early stage of life, the molecular markers are used along with traditional selection. The study was carried out to identify the genetic polymorphism in the exon3 region of the Prolactin and enumerate its effect on milk production performance in Sahiwal cattle. Prolactin plays an imperative regulatory role in mammary gland development, milk emission and lactogenesis. Analysed the sequence of this gene to explore whether mutations in this sequence and it could be accountable for quantitative variations in milk production and its composition traits.Methods: Total DNA was isolated from the blood samples of 98 pedigreed Sahiwal population. Using PCR-RFLP method and direct sequencing, noticed a single-nucleotide polymorphism in exon3 region of the Prolactin gene in 156bp and also the effect of non- genetic factors on each trait was assessed by least-squares analysis for non-orthogonal data by a fixed model.Result: PCR-RFLP was done with RsaI restriction endonuclease for the identification of different genotypes. The frequency of G and A alleles of the Prolactin gene was evaluated as 0.575 and 0.425, whereas the frequencies of GG, GA and AA genotypes for the Prolactin gene were 0.45, 0.25 and 0.30, respectively. SNP (G55A) conferred an increase in test-day milk yield around 321.5g, in test day fat yield around 13.9g and in test day SNF yield increase was 19.4g, respectively. High correlation was perceived from test day (TD2) onwards between test day traits and lactation milk yield indicating that selection based on identified SNP in TD2 increased test day milk yield, fat yield and SNF yield by 1.1472 kg, 29.6gm and 45.4gm, respectively.