Genetic polymorphism of three genes associated with milk trait in Egyptian buffalo

Genetic variants of CSN1S1, CSN2, CSN3, and BLG genes and their association with dairy production traits in Sahiwal cattle and Nili-Ravi buffaloes

Milk protein genes are associated with milk yield and composition in dairy animals. The present study aimed to identify milk protein genes (CSN1S1, CSN2, CSN3, and BLG) genetic variants and their association with milk yield in Sahiwal cattle and Nili-Ravi buffaloes. One hundred animals from each species were selected to collect blood samples and milk production records. Primers were designed for these milk protein genes for PCR amplification. Sequencing of resultant PCR products revealed a higher number of SNPs (13 vs. 7, 5 vs. 1, and 6 vs. 2) in Sahiwal as compared to Nili-Ravi animals in CSN1S1, CSN2, and CSN3 genes, respectively. However, a single SNP was observed in BLG gene of both species. Association analysis revealed that one SNP in BLG gene of Nili-Ravi was associated (p < 0.05) with 305-day milk yield. Two SNPs at CSN1S1 gene in Sahiwal were associated with dry-period. Similarly, one SNP at CSN1S1 and two SNPs at CSN3 gene showed significant association (p < 0.05) with average calving-interval in Sahiwal while two SNPs in CSN1S1 gene were associated (p < 0.05) with this trait in Nili-Ravi. These SNPs could be helpful as candidate variants for marker-assisted selection in cattle and buffaloes for improvement of lactation performance.

Single nucleotide polymorphisms within exon four of the prolactin gene and their effect on milk traits in cattle populations of Ethiopia

Bovine prolactin (PRL) gene is essential for the initiation and maintenance of lactation and exerts multiple effects on mammary alveoli to promote the synthesis and secretion of major components of milk. The objectives of this study were to identify mutations in PRL gene and to evaluate the mutations as potential markers of milk performance traits in cattle populations of Ethiopia. For this purpose, genomic DNA from whole blood was extracted through salting out procedure from 87 animals of five cattle populations of Ethiopia. Accordingly, three single nucleotide polymorphisms (SNPs) were identified of which one SNP g.8323T > A showed missense mutation while the other two SNPs revealed silent mutations. FST values showed statistically significant genetic differentiation among the studied populations. Intermediate polymorphic information content was noted for most SNPs, which indicates the presence of sufficient genetic variation at this locus. Two SNPs showed heterozygote deficiency as a result of positive FIS values. Only g.8398A > G SNP have statistically significant (p < 0.05) effect on average daily milk yield, fat and solid not fat percentage in all studied cattle populations. Therefore, g.8398A > G SNP identified in this study influences cattle milk production and may be used as possible candidate SNP for marker-assisted selection programs in cattle populations of Ethiopia.

Genetic polymorphism of Pit-1 and CSN3 genes in Holstein calves and its associations with calf birth weight

Abstract. The aim of this study was to examine the polymorphic structures of Pit-1 and CSN3 genes of Holstein calves bred in Gümüşhane province of Türkiye, to determine the distribution of genotype and allele gene frequencies, as well as examine the effects of determined polymorphisms on birth weight of calves. HinfI polymorphisms of Pit-1 and CSN3 genes were identified in DNA isolated from blood samples of 100 Holstein calves used in the study, using the PCR-RFLP method. According to the Hardy–Weinberg genetic equilibrium test, it was observed that the distribution of genotype frequencies of HinfI polymorphisms of Pit-1 genes in the studied population was in equilibrium, but not in equilibrium in terms of CSN3 gene location. The AA, AB, and BB genotype frequencies of the Pit-1 gene in the population were 13.4 %, 40.2 %, and 46.3 %, respectively; the frequency of the A allele was 0.34, while for B allele it was 0.66. The AA, AB, and BB genotype frequencies of the CSN3 gene were found to be 24.5 %, 36.7 %, and 38.8 %, respectively; the frequency of the A allele was 0.43 and the frequency of the B allele was 0.57. According to the Hardy–Weinberg genetic equilibrium test, the distribution of genotype frequencies was in equilibrium in the Pit-1/HinfI polymorphism, but not in the CSN3/HinfI polymorphism. A statistically significant relationship was not found between the genotypes of both polymorphic regions and calf birth weight.

Mulberry Leaf Flavonoids Improve Milk Production, Antioxidant, and Metabolic Status of Water Buffaloes

This study was aimed to evaluate the effect of mulberry leaf flavonoids (MLF) on oxidative stress, metabolic hormones, and milk production in Murrah buffaloes. Forty multiparous Murrah buffaloes (4 ± 1 lactations) with similar body weight (average 600 ± 50 Kg) and stage of lactation (90 ± 20 d) were randomly selected for this trial. Four treatment groups (10 buffaloes per group) with different doses of MLF included; control (0 g/d), MLF15 (15 g/d), MLF30 (30 g/d), and MLF45 (45 g/d). Buffaloes were fed with total mix ration consisting of grass (Pennisetum purpureum schum), brewery's grain and concentrate mixture for 5 weeks. Meteorological data including ambient temperature and relative humidity were recorded using the online dust monitoring system to calculate temperature-humidity index (THI). After 1 week of the adaptation, milk yield was recorded daily while physiological parameters (respiratory rate, rectal, and body surface temperature), and milk composition were measured weekly. At the end of the trial, blood samples were collected to analyze serum metabolic hormones including estradiol (E2), growth hormone (GH), prolactin (PRL), Tri-iodothyronine (T3), and Thyroxine (T4). Moreover, serum heat shock proteins (HSP), antioxidants enzymes including malondialdehyde (MDA), total antioxidant capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and blood biochemical indices were also analyzed. Results revealed a decrease (P = 0.012) in serum MDA level while increasing (P < 0.01) the HSP and serum GHS-Px contents in supplemented buffaloes. Treatment showed a linear and quadratic decrease (p = 0.001) in the serum T-AOC while reducing CAT contents linearly (p = 0.012) as compared to the control. However, no effect of treatment on serum SOD content was observed. Treatment resulted a linear increase (p = 0.001) in serum GH and PRL hormones while increasing serum E2 levels linearly (P < 0.001) and quadratically (P = 0.025). Treatment increased (p = 0.038) the daily milk yield as compared to the control. However, increase (P < 0.05) in serum T3 and T4 contents, fat corrected milk (4%) and milk protein (%) was observed only in MLF45. Moreover, we observed no change in serum biochemical indices except insulin which linearly increased (p = 0.002) in MLF45. Our findings indicated that MLF at 45 g per day is an appropriate level to enhance milk performance and alleviate heat stress in buffaloes.

Effect of DGAT1, FASN and PRL genes on milk production and milk composition traits in Simmental and crossbred Holstein cattle

The aim of this study was to evaluate the effects of polymorphisms in the acylCoA diacylglycerol acyltransferase (DGAT1), fatty acid synthase (FASN) and prolactin (PRL) genes on milk production traits and the potential influence of the PRL gene on SCC of Simmental and crossbred Holstein cattle as well as comparatively among them. A total of eighty-three cows were genotyped by PCR-RFLP method. Crossbred Holsteins with DGAT1 genotype KA hadsignificantly higher fat content than cows with AA genotype and for FASN diplotype TW/AR had significantly higher fat content compared to diplotype AR/AR. In the observed group of animals, there was no association found between PRL SNP G8398A and milk production traits and SCC (SCS). For all three genes, cross bred Holstein hadsignificantly higher milk yield, fat and protein content in certain genotypes/diplotypes. The results of combined genotype analysis of the three SNPs showed that GG/TWAR/KK genotype combination had the lowest SCS.