THE EFFECT OF KAPPA-AND BETA-CASEIN GENOTYPES ON BREEDING VALUES OF MILK PRODUCTION TRAITS IN HOLSTEIN SIRES ORIGINATED IN MOSCOW REGION

Проведены исследования на 103 быках-производителях голштинской породы черно- и красно-пестрой масти Московской области, оцененных методами BLUP и GBLUP. Производителей разделили на 3 группы в зависимости от года их рождения (г. р.): до 2005 г. р. (n=18), с 2006 по 2010 г. р. (n=34) и с 2011 по 2013 г. р. (n=51). Интерес представляло изучение генотипов по генам каппа- (κ-CSN) и бета-казеина (β- CSN), потенциально связанных с повышенным содержанием белка и продуцированием коровами «гипоаллергенного» молока А2. Однофакторный дисперсионный анализ показал значимое влияние генотипа по гену κ-CSN (P<0,001) и тенденцию для β-CSN на изучаемые показатели племенной ценности голштинских быков. Установлено, что носители генотипа BB гена CSN3 имеют превосходство в сравнении с животными, имеющими генотип АА, по количеству молочного жира и белка в молоке – на 16,8 кг и 13,2 кг соответственно, что важно при производстве молочных продуктов. Встречаемость у исследуемых быков-производителей генотипов А2А2 по гену бета-казеина (n=41) имеет большую численность в сравнении с А1А1 (n=21), что подразумевает возможным формирование специализированного стада для получения молока А2 путем группировки животных по результатам генотипирования. По мере накопления результатов оценки быков-производителей по качеству потомства, исследования в направлении изучения влияния генотипов по генам белков молока будут продолжены. The main purpose of this article was to study kappa-and beta-casein genotypes significantly associated with an increased protein content and the production of «hypoallergenic» 2A milk. The study involved 103 Black and Red-and-White Holsteins in Moscow region estimated by BLUP and GBLUP procedures. In order to evaluate the effectiveness of the study Holstein sires were selected into three groups according to their age (born in 2005) (n=18), from 2006 to 2010 (n=34) and from 2011 to 2013 (n=51). The ANOVA analysis showed a considerable effect of the genotype for the k-CSN gene (P<0,001) and the trend for β-CSN on the studied traits of breeding value of Holsteins. The highest performance in terms of amount of milk fat and protein showed that the cows with CSN3 BB group had a significant advantage in comparison with the cows of AA genotype by 16.8 kg and 13.2 kg, respectively, which is important in the dairy production. The frequency of the occurrence of homozygotes of A2A2 beta-casein (n=41) in the cows was the highest amounting in comparison with the A1A1 genotype (n=21) which implies that it is possible to form a specialized herd for obtaining A2 milk by grouping animals according to the results of genotyping. As the results of assessment of the sires’ breeding value accumulate, the study of the effect of genotypes on the milk protein genes will be pursued.

The Polymorphism in Various Milk Protein Genes in Polish Holstein-Friesian Dairy Cattle

The aim of the present study was to evaluate the genotype and allele frequencies of 24 polymorphisms in casein alpha S1 (CSN1S1), casein alpha S2 (CSN1S2), beta-casein (CSN2), kappa-casein (CSN3), and progestagen-associated endometrial protein (PAEP) genes. The study included 1900 Polish Black and White Holstein-Friesian dairy cows that were subjected to genotyping via microarrays. A total of 24 SNPs (Single Nucleotide Polymorphisms) within tested genes were investigated. Two CSN1S1 SNPs were monomorphic, while allele CSN1S1_3*G in CSN1S1_3 SNP dominated with a frequency of 99.39%. Out of seven CSN2 SNPs, four were polymorphic; however, only for CSN2_3 all three genotypes were detected. Only three out of nine SNPs within CSN3 were monomorphic. Three PAEP SNPs were also found to be polymorphic with heterozygotes being most frequent. Hardy–Weinberg equilibrium (HWE) was observed for eight variants. It was shown that only CSN3_6 was not in HWE. The fact that many of investigated SNPs were monomorphic may suggest that in the past the reproduction program favored one of these genotypes. SNPs that are included in commercially available microarrays should be monitored in relation to changes in their frequencies. If a SNP has turned monomorphic, maybe it should be considered for removal from the microarray.

Nrf2-ARE Signaling Partially Attenuates Lipopolysaccharide-Induced Mammary Lesions via Regulation of Oxidative and Organelle Stresses but Not Inflammatory Response in Mice

The incidence of mastitis is high during the postpartum stage, which causes severe pain and hinders breast feeding in humans and reduces milk production in dairy cows. Studies suggested that inflammation in multiple organs is associated with oxidative stress and nuclear factor E2-related factor 2 (Nrf2)-antioxidant response element pathway is one of the most important antioxidant pathways, but the effects of Nrf2 on antioxidation in the mammary gland during mastitis are still unclear. In this study, intramammary lipopolysaccharide (LPS) challenge was carried out in wild-type (WT) and Nrf2 knockout mice. Results showed that the expression of Nrf2 affected the expression of milk protein genes (Csn2 and Csn3). Importantly, LPS treatment increased the expression of Nrf2 and HO-1 and the content of glutathione in the mammary gland of WT mice, but not in Nrf2(-/-) mice. The expression levels of glutathione synthesis genes (GCLC, GCLM, and xCT) were lower in Nrf2(-/-) mice than in WT mice. Moreover, mitochondrial-dependent apoptotic and endoplasmic reticulum stress were significantly relieved in WT mice compared with that in Nrf2(-/-) mice. In summary, the expression of Nrf2 may play an important role in prevention of oxidative and organelle stresses during endotoxin-induced mastitis in mouse mammary gland.

ECONOMICALLY USEFUL QUALITIES OF JERSEY CATTLE IN THE SELECTION OF MILK PROTEIN GENES CSN2 AND CSN3

В данной статье дана частота встречаемости носителей генотипов по локусам CSN2 и CSN3 и оценена степень влияния CSN2 и CSN3 генотипов на молочную продуктивность у животных джерсейской породы. Проведено генотипирование 697 (609 телок и 88 коров) животных джерсейской породы, проанализирована информация о 178 джерсейских быках-производителях. Установлено, что в различных группах животных частота встречаемости «предпочтительных» в хозяйственном отношении локусов CSN2 генотипа А2А2 составляет от 0,50 до 0,80 и CSN3 генотипа ВВ — от 0,66 до 0,88. Высокая частота встречаемости «желательных» CSN2 и CSN3 генотипов позволяет создать джерсейское стадо с генотипами А2А2 и ВВ гораздо быстрее, чем у крупного рогатого скота других пород. Генотипы А2А2 и ВВ (локусы CSN2 и CSN3) не оказывают негативного влияния на молочную продуктивность их носителей. In this article, the frequency of occurrence of carriers of genotypes at the CSN2 and CSN3 loci is given and the degree of influence of CSN2 and CSN3 genotypes on milk productivity in Jersey animals is estimated. Genotyping of 697 (609 heifers and 88 cows) Jersey animals was performed, and information about 178 Jersey bulls was analyzed. It was found that in different groups of animals, the frequency of occurrence of «preferred» loci in the economic relation CSN2 genotype A2A2 is from 0.50 to 0.80 and CSN3 genotype BB — from 0.66 to 0.88. The high frequency of occurrence of «desirable» CSN2 and CSN3 genotypes makes it possible to create a Jersey herd with genotypes A2A2 and BB much faster than in cattle of other breeds. The A2A2 and B genotypes (CSN2 and CSN3 loci) do not negatively affect the milk productivity of their carriers.

Genetic Variants of Milk Protein Genes and Their Association with Milk Components in Holstein Friesian Cattle

Protein content in milk is an important indicator of milk. Accordingly, genetic improvement to produce Holstein Friesian (HF) dairy cattle is important. The objective of this study was to evaluate the genetic variant of milk protein genes and its effect on milk component traits of Holstein Friesian (HF). A total of 100 HF were used in this study. The HF cattle used have physiological status in the lactation period 1 up to 3 and lactation change of 1 up to 12 months. Genotype variants of milk protein genes were identified using Real Time-Polymerase Chain Reaction method. Analysis of milk component was carried out covering the component of protein, fat, lactose, and solid non-fat (SNF) by using a milk quality measuring device (Lactoscan). Genotyping of cattle blood samples consisted of DNA extraction, genes amplification using the RT-PCR method. The result showed that<strong> </strong>protein milk was significantly affected (p&lt;0.05) by the genetic variants of CSN1S1-192 and CSN2-67 genes. Fat milk was significantly affected (p&lt;0.05) by the genetic variants of CSN1S1-192 and CSN3 genes. Meanwhile, solid non-fat milk was significantly affected (p&lt;0.05) by the genetic variants of CSN-BMC9215, CSN-BMC6334, CSN1S1-14618, CSN2_67, and CSN3 genes. Lactose milk was significantly affected (p&lt;0.05) by the genetic variants of CSN-BMC9215 and CSN2-67 genes. It was concluded that genetic variants of the milk protein genes have an association with the component of cow's milk (protein, fat, solid non-fat, and lactose).

Vinculins interaction with talin is essential for mammary epithelial differentiation

Vinculin is an essential component of cell adhesion complexes, where it regulates the strength and stability of adhesions. Whilst the role of vinculin in cell motility is well established, it remains unclear how vinculin contributes to other aspects of tissue function. Here we examine the role of vinculin in mammary epithelial cell phenotype. In these cells, correct adhesion to the extracellular matrix is essential for both the formation of polarised secretory acini and for the transcription of tissue-specific milk protein genes. We show that vinculin, through its interaction with talin, controls milk protein gene expression. However, vinculin is not required for the formation of polarised acini. This work reveals new roles for vinculin that are central to cellular differentiation, and for the ability of cells to interpret their extracellular microenvironment.

THE EFFECT OF COWS GENOTYPE ON THEIR PRODUCTIVITY AND MILK QUALITY

As studies by Russian and foreign scientists show, the breed and the cows genotype affects on their productivity and milk quality. In connection with this, the purpose of this research was to study the milk productivity and milk quality of the Tatarstan type Kholmogory cows with different complex genotypes on the milk protein genes, namely, alpha S1-casein, beta-casein, kappa-casein, beta-lactoglobulin, alpha-lactalbumin. The genotypes on the milk protein genes were determined by DNA analysis methods. Determination of quantitative and qualitative indicators of milk was carried out by control milking and on a milk analyzer «LAKTAN1–4». Better raw milk, that is, with the greatest amount of nutrients, such as milk fat and protein, was milk from cows with complex genotypes of milk proteins ВВ/АВ/АВ/АВ/АА, ВВ/АВ/АВ/АВ/АВ, ВВ/АВ/АВ/АВ/ВВ. In practical terms, it is possible to get more quality dairy products from such raw materials.

Relationships between milk protein polymorphisms and production traits in cattle: a systematic review and meta-analysis

Many researchers who have studied the relationships between milk protein polymorphisms and some yield traits in dairy cattle have reported incompatible results. In this study, in order to examine the overall relationships between milk protein genes known as major genes (CSN1S1, CSN2, CSN3, and BLG) and some yield traits (daily milk yield, lactation milk yield, fat yield, fat content, protein yield, and protein content), a meta-analysis was performed using some genetic models reported in the results of previous studies on cattle. The results suggest that the relationships of major milk protein genes with other factors should be studied using the codominant genetic model in general. Relationships among some CSN3 genotypes and fat yield, fat content, and protein content, and relationships between some BLG genotypes and daily milk yield, fat content, protein yield, and protein content were significant (P<0.05). No significant (P>0.05) relationships were found between these genotypes and other milk production traits. In addition, no significant (P>0.05) relationships between the CSN1S1 and CSN2 genotypes with the milk production traits examined were observed.