Il Gene SREBP-1 e le caratteristiche del latte in ovini di razza Sarda

SREBF are a family of transcription factors structurally related that play an important role in the lipid homeostasis adjusting the expression of genes involved in cholesterol, fat acids, triglycerides and phospholipides synthesis. Nowadays 3 SREBP isoforms have been discovered: 1a, 1c and 2. 1c isoform is involved in the fat acids synthesis and in the insulin-induced metabolism, 2 isoform is specific in the cholesterol biosynthesis while 1a is involved in both way. The aim of this research was to characterize the entire coding sequence of SREBP-1 gene in Sarda breed sheep and to evaluate the association between SREBP-1 gene polymorphism and production traits. We used 80 Sarda breed sheep of 2 farm located in north Sardinia with the same food and management condition. Daily milk yield for each animal was determined and also milk samples (50 ml each) were collected to laboratory analysis. 10 ml of blood were collected from each animal to extract DNA genomic. 19 couple of primers were used to amplify the entire coding sequence. SSCP analysis (Single Strand Conformation Polymorphism) was used to resolve the PCR products. We discovered 8 SNPs. The polymorphism localization are as follow: G980T, G981T, C1686T, C5448T, G5657A, G5688A and C6872T. 12 haplotypes were found but only 7 showed a frequency over 0,02. No correlation was found between SNPs and milk traits. None significant association between 7 haplotypes and milk traits were detected

Polymorphism of the MTNR1A Melatonin Receptor Gene in Goat Breeds of Northern Italy

Melatonin receptor MT1, encoded by the MTNR1A gene, is the main one involved in the seasonal regulation of reproductive activity. A correlation between this gene polymorphism and reproductive performance has been demonstrated in sheep. To date, no data about MTNR1A gene polymorphism are available regarding Italian goat breeds other than the Sarda goat. This study aimed to detect any PCR-RFLP polymorphic sites of MTNR1A using MnlI and RsaI enzymes in Northern Italian goat breeds, which are characterized by a pronounced reproductive seasonality. One-hundred-eight adult female goats belonging to four different breeds were included in the study (i.e., Frisa Valtellinese, n = 29; Orobica, n = 23; Lariana, n = 29; Camosciata delle Alpi, n = 27). Blood was sampled from each goat. Genomic DNA was extracted from each sample and the main part of exon II of MTNR1A gene was amplified by PCR and digested with MnlI and RsaI enzymes. Unexpectedly, none of the fragments were found to be polymorphic. The absence of polymorphism may be linked to the macro group of goat breeds that evolved during human migrations. Breeds of the Alpine-European strain would appear to show no polymorphism, as confirmed by our study, whereas breeds belonging to the Mediterranean-African or Asian-Middle Eastern strains do

Characterization of the SREBP-1 Gene Polymorphisms and Milk Traits in Dairy Sheep

The SREBP genes (Sterol Regulatory Element-Binding Proteins) are involved in the milk fat synthesis. In dairy cows some polymorphisms at the SREBP-1 gene sequence have been related with milk fat content. The aim of this study was to characterize the entire coding regions of the SREBP-1 gene in Sarda sheep breed, in order to highlight any polymorphisms and their association with milk traits. Four-hundred adult and lactating Sarda ewes were selected. Individual milk yield was recorded monthly from Day 30 to Day 150 of lactation, and fat and protein concentration were analysed. A blood sample from each ewe was taken for DNA extraction; thus, all the 19 coding exons of the SREBP-1 gene were amplified by polymerase chain reaction (PCR). Single-strand conformation polymorphism analysis (SSCP) and sequencing were used to scan mutations. Results provide, for the first time, the entire coding DNA sequence (CDS) of the SREBP-1 gene in sheep, and by sequences analysis 8 polymorphisms have been detected. The statistical analysis exhibited no relationship between polymorphisms and milk traits. The low SREBP-1 gene diversity that emerged from the present study, may be linked to the important role of this gene in the mechanism of milk fat synthesis or to the severe genetic selection performed in the Sarda sheep. However, it would be necessary to extend the study, including other breeds and other genes, in order to expanding the knowledge about the process of milk fat synthesis in dairy sheep

Reproductive Resumption in Winter and Spring Related to MTNR1A Gene Polymorphisms in Sarda Sheep

The aim of the present research was to evaluate the association between the SNPs rs430181568 and rs407388227 located in the MTNR1A gene with the reproductive recovery of Sarda sheep in different months of ram introduction in the flock (February, March, April and May). In order to address this research gap, we selected two farms, each of which consisted of approximately 1000 animals; a total of 800 ewes (400 for each farm) were genotyped for the two single nucleotide polymorphisms rs430181568 and rs407388227 located in the exon 2 of the MTNR1A. These SNPs are completely linked; thus, each genotype of rs430181568 corresponded to the same genotype for rs407388227. Among the genotyped animals, 240 individuals were selected and divided into four homogeneous groups (A, B, C and D) of 60 subjects, each group based on age (range 3–6 years old), body condition score (BCS) (range 2.0–4.0) and genotype (20 ewes carrying CC/CC, 20 CT/CT and 20 TT/TT genotype). The dates of the ram introduction in each group were 15 February, 15 March, 15 April and 15 May, respectively. In all groups, the lambing date and the number of lambs born from 150 to 220 days after the ram introduction were recorded. In all the groups, the genotypes CC/CC and CT/CT of the polymorphism (rs430181568 and rs407388227) showed the greatest fertility (the ratio between the number of lambed ewes and the ewes exposed to the rams) (p < 0.01) and the shortest distance between ram introduction to lambing (p < 0.01), compared with the TT/TT genotype. In conclusion, we determined that the polymorphisms rs430181568 and rs407388227 were associated with reproductive recovery, after ram introduction, even in February and March, months subsequent to the photorefractoriness period

Discrepancies between Genetic and Visual Coat Color Assignment in Sarcidano Horse

This study aimed to evaluate the discrepancies between genetic and visual coat color assignment in the Sarcidano Horse and to elucidate potential reasons. Individual DNA from 90 Sarcidano Horses was used for genetic assignment of coat color to explore the correspondence with individual forms containing phenotypical traits. The MC1R exon 1 and ASIP exon 3 have been genotyped and sequenced to obtain a picture of the coat color distribution in this breed. Surprisingly, once we compared the genetic results with the individual forms reporting the phenotypic data for each subject, a certain degree of non-correspondence between the phenotypic and genetic data in relation to coat color emerged. From the genetic analysis, Chestnuts (n = 58) resulted the most common Sarcidano Horse (n = 58), followed by a quite large number of Blacks (n = 28) and a very small number of Bays (n = 4), whereas phenotypic distribution resulted in 38 Chestnuts, 40 Bays, only 2 Blacks, and 10 Grays (without the possibility of recognizing the true color they carried). Chestnut resulted a very representative coat color, while many horses that visually identified as Bays were genetically Blacks. This discrepancy, that could be due to a variety of individual and external factors, including age, time of year, living situation and dietary condition, suggesting the importance of accurate coat color identification to ensure adequate features registration and reliable prediction of offspring’s coat color

Melatonin Treatment in Rams and Their Replacement with Novel Treated Rams Advance First Lambing and Increase Fertility in Sarda Ewe Lambs

This study aims to find reliable strategies for advancing first mating and shortening the period from weaning to first lambing in ewe lambs. Sarda ewe lambs (n = 400) were selected from two farms and allocated into four separated groups of 100, all of which were exposed to fertile, adult rams over the course of a 50-day breeding period. The first treatment group (RMR) was exposed to four melatonin-treated rams which were replaced every ten days, whilst the second treatment group (RM) was exposed to four melatonin-treated rams which were not replaced. Alternatively, the first control group (RCR) was exposed to four untreated rams which were replaced every ten days, whilst the second control group (RC) was exposed to four untreated rams which were not replaced. In each group, lambing dates, fertility rate, litter size, and distance in days from ram introduction to lambing (DRIL) were recorded. The highest fertility rate was recorded in the RMR group (p ≤ 0.05). Shorter DRIL (p ≤ 0.01) and higher lambing concentrations were recorded in the RM and RMR groups as compared to the controls. The findings indicate that melatonin treatment of rams and their replacement at 10-day intervals results in earlier onset of first mating, increased fertility rate in ewe lambs, and a higher number of ewes that lambs in a shorter time frame

Characterization of the Sarcidano Horse Coat Color Genes

The goal of this study was to contribute to the general knowledge of the Sarcidano Horse, both by the identification of the genetic basis of the coat color and by updating the exact locations of the genotyping sites, based on the current EquCab3.0 genome assembly version. One-hundred Sarcidano Horses, living in semi-feral condition, have been captured to perform health and biometric checks. From that total number, 70 individual samples of whole blood were used for DNA extraction, aimed to characterize the genetic basis of the coat color. By genotyping and sequencing analyses of the MC1R Exon 1 and ASIP Exon 3, a real image of the coat color distribution in the studied population has been obtained. Chestnut and Black resulted in the most representative coat colors both from a phenotypic and genotypic point of view, that is suggestive of no human domestication or crossbreeding with domestic breed. Due to its ancient origin and genetic isolation, an active regional plan for the conservation of this breed would be desirable, focused on maintenance of resident genotypes and genetic resources. Collection and management of DNA, sperm, embryos, with the involvement of research centers and Universities, could be a valid enhancing strategy

Effects of melatonin treatment on milk traits, reproductive performance and immune response in Sarda dairy sheep

In ruminants, the role of melatonin in the control of reproductive seasonality is well reported, but it is still little known about its action on milk traits and on the immune system. The aim of this study was to assess the effect of melatonin on milk yield and composition, somatic cell count (SCC), some cytokine blood concentration and reproductive resumption in sheep. One hundred lactating sheep were allocated to two groups (of 50 sheep each), M (treated with melatonin) and C (controls), and exposed to the rams for 50 d. Time period in days from ram introduction to lambing (TRIL) and litter size were recorded. Every 15 d, from 1 March to 30 April, the individual daily milk yield was registered and milk composition and SCC, were analysed. The levels of Interleukin 2 and 6 (IL-2 and 6) and tumour necrosis factor-alpha (Tnf-α) were evaluated every 15 d. The highest fertility rate (p < .01) and the shortest TRIL (p < .05) was recorded in M group. Milk yield and composition were similar between groups. The somatic cells decreased continuously in the treated ewes (p < .01) and increased continuously in untreated ewes (p < .05). IL-2 and IL-6 increased in M group, although no statistical differences were found between groups. Melatonin administration improved reproductive efficiency, did not affect milk yield and composition and decreased somatic cells. This last effect could help to maintain healthy mammary gland and encourage farmers to reduce the use of drugs against mastitis.Highlights Melatonin is involved in different physiological processes, such as the control of reproductive seasonality, milk production and the immune response. Melatonin administration in Sarda sheep did not modify milk yield and composition, decreased SCC and advanced reproductive resumption in spring. Melatonin could be used to strengthen the sheep immune response in order to reduce the use of drugs for both therapeutic and preventive purposes against mastitis