Cinzia Daga

D-loop sequence mitochondrial DNA variability of Sarda goat and other goat breeds and populations reared in the Mediterranean area

To provide useful knowledge on goat breed origin and history, we studied the mitochondrial DNA (mtDNA) of 69 goats from five different breeds, Camosciata delle Alpi, Maltese, Nubian, Saanen and Sarda, and one population, the Tunisian. All goats analysed displayed a moderate haplotype and nucleotide diversity. The highest was in the Sarda - the autochthonous breed reared in Sardinia. On the basis of mtDNA control region sequences, animals showed a high genetic haplotype diversity, 35 haplotypes were each represented by a single sequence and only a few haplotypes were shared among the animals. New haplotypes of goats reared in the Mediterranean area were identified and the majority of Italian goats belonged to haplogroup A. This result confirmed worldwide distribution and diversity of haplogroup A.

A polymorphism at the melatonin receptor 1A (MTNR1A) gene in Sarda ewes affects fertility after AI in the spring

The effect of MTNR1A gene polymorphisms on the fertility rate after AI in Sarda sheep was evaluated in 600 lactating adult ewes. Genomic DNA was subjected to amplification of the MTNR1A gene exon II. Amplicons were digested with restriction endonuclease MnlI. Ten samples from each genotype were sequenced. A polymorphism was detected (A612G) and ewes were determined to be +/+, +/- or -/- for the allele. Allelic frequency was 0.77 for the+allele and 0.23 for the - allele. The frequency of the +/+, +/- and -/- genotypes was 68, 19 and 13%, respectively. On 16 May 2009, 60 ewes from each genotype group were synchronised using intravaginal sponges containing 40 mg fluorogestone acetate for 14 days. At sponge removal, the ewes were administered 350 IU pregnant mares serum gonadotropin and were then inseminated, 54-56 h later, with 400 × 10(6) spermatozoa. Pregnancies were confirmed 50 days after AI using transabdominal ultrasonography. Lambing dates and the number of newborn lambs were recorded within 155 days after AI. Conception and lambing rate were higher for ewes with the +/+ and +/- genotypes compared with those with the -/- genotype (P<0.01). In conclusion, there was a positive correlation between MTNR1A allele polymorphisms the reproductive response following synchronisation and AI in the spring.

Influence of melatonin receptor 1A gene polymorphisms on seasonal reproduction in Sarda ewes with different body condition scores and ages

In several species, circadian changes in melatonin concentrations play a key role in the photoperiodic control of seasonality. In sheep, two silent mutations in the melatonin receptor 1A gene (MTNR1A) at positions 606 and 612 of the exon II are associated with seasonal reproduction. However, in some sheep breeds, no relationships have been found between MTNR1A polymorphisms and reproductive seasonality. This lack of relationship could be due to effects of breed, body condition, age, and/or environmental conditions. Thus, the present study was conducted with the Sarda sheep breed with the aim of documenting the effect of MTNR1A gene polymorphisms on reproductive resumption and to evaluate whether such this effect was modified by differences in body condition score (BCS) and age. Six hundred three- to six-year-old multiparous ewes with BCSs between 2.5 and 3.5 were selected. Genomic DNA was extracted and subjected to PCR to amplify the ovine exon II of the MTNR1A gene. The amplicons were subjected to digestion with the restriction enzymes RsaI and MnlI to detect the T606C and A612G polymorphisms, respectively. Ewes carrying the G/G, G/A, C/C, and C/T genotypes exhibited higher fertility rates (P<0.05) and fewer numbers of days between the introduction of rams and parturition (P<0.05) than did the A/A and T/T genotypes. The data revealed that the MTNR1A gene polymorphisms influenced spring reproductive resumption in the Sarda sheep breed. Moreover, the data also indicated that, over the limited ranges evaluated in this study, BCS and age had no significant influence on reproductive activity.

Characterization of the melatonin receptor gene MT1 in mouflon (Ovis Gmelini Musimon) and its relationship with reproductive activity.

The goals of the present research were to characterize the MT1 gene in mouflon, identify possible polymorphisms, and facilitate a better understanding of their relationship with reproductive activity.

Association between SREBP-1 gene expression in mammary gland and milk fat yield in Sarda breed sheep.

Summary The aim of this study was to examine the expression patterns of SREBP-1 gene in milk somatic cells and its association with milk fat yield during early lactation in Sarda breed sheep. A sample of 20 Sarda ewes, aged between 4 and 5 years, in their third to fourth lactation were chosen. From each ewe 28 days after lambing milk yield was measured, and a 160 ml milk sample for the RNA extraction and to test somatic cells count and lactose, fat and protein contents were collected. From the obtained RNA, total cDNA was synthesized and the quantitative PCR was performed. The fat, proteins and lactose content showed many differences among the animals, but these variations were no correlated with the milk yield. The SREBP-1 gene expression resulted higher in the high milk fat producing ewes. The correlation analysis showed that the SREBP-1 expression level is directly related to the amount of milk fat (g/die) (P < 0.001), while the total RNA obtained from each sample was found to be related to the somatic cells number (P < 0.001). Instead the expression of this gene showed no relations with the concentration of fat in milk. Our data highlight that in sheep SREBP-1 gene is expressed in the mammary gland during early lactation. Moreover, the positive relationship between SREBP-1 gene expression and the milk fat yield suggests that SREBP-1 gene is required for the lipid synthesis in the sheep mammary gland.

Can advance of first lambing induced by melatonin implants influence the next lambing time in Sarda breed sheep

Carcangiu, V., Mura, M. C., Bini, P. P., Vacca, G. M., Daga, C. and Luridiana, S. 2012. Can advance of first lambing induced by melatonin implants influence the next lambing time in Sarda breed sheep? Can. J. Anim. Sci. 92: 67-71. In adult sheep, exogenously administered melatonin from continuous slow-release implants has been shown to advance the onset of the breeding season by mimicking the stimulatory effect of short days. The aim of this study was to verify if treatment with one or two melatonin implants was effective in advancing the first conception in Sarda ewe lambs, and if this advance would also be seen in the second lambing too. In the first year, 600 ewe lambs were randomly assigned to groups M, M+M and C, each with 200 animals. On Jun. 30, group M received a single implant while group M+M received two implants. Group C was untreated. On Aug. 04, 25 rams were introduced in the groups and removed after 70 d. From these 600 animals the 420 head that lambed prior to Mar. 12 were chosen for the second year. These ewes were subdivided into two groups T1 (ewes who lambed between 2007 Jan. 01 and Feb. 10) and T2 (ewes which lambed between 2007 Feb. 11 and Mar. 12). Both in T1 and T2 the distribution of the animals in M, M+M and C group was maintained. In the first year, the treated animals lambed earlier (P<0.05) and showed higher numbers of lambed ewes at Feb. 10 (P<0.01) and at March 12 (P<0.05) compared with untreated control animals. The animals that showed an advance in the period of their first conception, also showed, in the second breeding year, an advance in the lambing time (P<0.001). This study provides evidence that the advance of first conception, obtained with melatonin treatment also influenced the reproductive activity in the following breeding season.

Influences of melatonin treatment, melatonin receptor 1A (MTNR1A) and kisspeptin (KiSS-1) gene polymorphisms on first conception in Sarda ewe lambs

In order to investigate if the melatonin receptor 1A (MTNR1A) and kisspeptin (KiSS-1) genes influence the reproductive response to melatonin treatment, 510 Sarda ewe lambs were divided into groups C (control) and M; Group M received one melatonin implant (18mg). After 35 days rams were introduced for 40 days and subsequent lambing dates and number of newborns were recorded. The MTNR1A gene Exon II and KiSS-1 gene Exon I were amplified and genotyped by restriction fragment length polymorphism (RFLP) and single-strand conformation polymorphism analysis. Two single nucleotide polymorphisms (SNPs; C606T and G612A) in MTNR1A and one (G1035A) in KiSS-1 were found. The most frequent genotypes were G/G (63%) and C/C (53%) for MTNR1A and G/G (92%) for KiSS-1. Treated animals showed a higher lambing rate (P<0.05) and an advanced lambing date (P<0.05) compared with controls. The three SNPs did not influence the onset of reproductive activity. The majority of the G/G animals of Group M lambed before 190 days after ram introduction (P<0.05), while in Group C a higher number of G/G animals lambed after this date. Data revealed the positive effect of melatonin treatment on the time of first conception in ewe lambs and highlighted that the G/G genotype of the MTNR1A gene is able to influence the reproductive response to melatonin treatment.

Genotype at the MTNR1A locus and response to melatonin treatment in Sarda lambs

Abstract With the aim to evaluate the effect of melatonin treatment and melatonin receptor 1A (MTNR1A) genotype on advance of puberty, 423 Sarda lambs were chosen. On June 26th, they were divided into three groups, each of 141 animals (groups 0, 1, and 2), on the basis of live weight. On June 30th, animals in group 1 received a single implant (18 mg melatonin), while group 2 received two implants. Group 0 was untreated. Thirty-five days after treatment (August 4th), rams were introduced and after 40 days they were removed. From January 1st to February 10th lambing dates were recorded. Genomic DNA was extracted and subjected to PCR for the amplification of exon II and then digested with enzymes MnlI and RsaI and placed into +/+, +/., or ./. group for MnlI and C/C, C/T, or T/T group for RsaI. Samples were cloned and sequenced. Data obtained were subjected to χ2 test in order to evaluate the difference in fertility among groups and the link between genotype and reproductive activity. Genotype +/+ and C/C showed the highest incidence. Treated groups showed a higher number of lambing at 10th February compared to control group (P<0.04). Melatonin treatment results more efficient in +/+ genotype.