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.

Melatonin treatment in spring and reproductive recovery in sheep with different body condition score and age.

With the aim to evaluate the effect of melatonin treatment on the advanced reproductive recovery in sheep with different body condition score (BCS) and age, 800 ewes were selected from two farms. These ewes (3-6 years old, multiparous and with BCS 2.5-4.0) were subdivided into two Groups (200 M and 200 C), balanced on their BCS and age. On 20 March, Group M was treated with one melatonin implant (18 mg). Group C was untreated. Males were introduced to the groups 35 days after treatment. Gestation was diagnosed between day 45 and 90 after mating by transabdominal ultrasonography. From day 150 to 190 after rams introduction, lambing date and newborns' number were recorded. The average time in days between male introduction and lambing resulted shorter in treated than in control ewes (166.4 ± 0.48 vs. 172.5 ± 0.50) (P < 0.05). At day 160 and 170 from ram introduction the fertility rate was higher in Group M than in C (P < 0.05). The overall fertility at day 190 from rams introduction showed no differences between Group M and C (337 and 339, respectively). At day 170 from male introduction the number of the 5-6 years-old lambed ewes were 2-fold higher than the youngers (P < 0.05). The animals with a BCS 3.5-4.0 had a faster response to male effect, and a shorter mean distance in days from rams introduction to lambing, compared to those scored 2.5-3.0 (166.1 ± 0.48 vs. 174.8 ± 0.51) (P < 0.05). We concluded that the ewes with BCS 3.5-4.0 and aged 5-6 years showed a better response to melatonin treatment in 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 Mediterranean Italian buffaloes melatonin receptor 1A (MTNR1A) gene and its association with reproductive seasonality.

The aim of this study was to examine the polymorphism in MTNR1A gene and its relation to reproductive seasonality in Mediterranean Italian buffaloes reared in Sardinia. The mating period and calving of 100 multiparous buffalo-cows were recorded for three years (2005-2008). Genomic DNA was subjected to PCR for the amplification of the exon II, then 40 amplicons were sequenced. The obtained sequence was deposited in GeneBank database (accession number GU817415). PCR products were checked for the presence of HpaI restriction sites and assigned to genotypes "C/C", "C/T" or "T/T". Allelic frequency of C and T alleles was 0.44 and 0.56 and genotypic frequency was 26% for genotype C/C, 40% for C/T and 34% for T/T. In the three observed years the animals with C/C genotype showed the highest number of mating in the semester between August and January and their calving mainly occurred from August to September. On the other hand animals with T/T genotype showed mating mostly in the semester between February and July and calving occurred largely from March to May in all the three years. Heterozygous, in all the three years, showed about the same number of animals mated within each six-month period. The results of the present study provide for the first time a partial sequence as well as one polymorphic site of the MTNR1A receptor gene from buffaloes. Moreover our data showed an association between Single Nucleotide Polymorphism and seasonal reproductive activity in these animals.

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.

Hidrobiología del Embalse La Quebrada (Córdoba), Argentina: bacteriología y fitoplancton

El Embalse La Quebrada, localizado en Río Ceballos, a 32 Km al Noroeste de la ciudad de Córdoba, es el único reservorio para provisión de agua potable de aproximadamente 30.000 personas que viven en los alrededores, en las localidades de Río Ceballos, Unquillo y Mendiolaza. Desde 1997 se ha detectado un incremento en el proceso de eutroficación del lago, manifestándose principalmente en florecimientos de algas. En la actualidad el lago tiene periódicamente importantes blooms de Ceratium hirundinella (Dinofíceae), que se ven en la superficie del agua como manchones rojizos. También ha habido en los últimos años una interesante variación en dominancia entre Cianobacterias indicadoras de eutroficación, tales como las especies pertenecientes a los géneros Anabaena y Microcystis. En esta contribución se presentan datos varios correspondientes a muestreos efectuados no solamente en el Embalse sino además en sus dos tributarios.Los parámetros estudiados incluyen las más importantes características físico-químicas, microbiológicas y fitoplanctónicas que sirven para estimar calidad de aguaLos resultados indican que el Embalse podría ubicarse en un estadio mesotrófico, con marcada tendencia a eutrófico. Sus aguas se caracterizan por abundante productividad primaria, baja transparencia, procesos anaeróbicos en el hipolimnion que generan gases odoríferos, y recirculación de nutrientes con una alta carga de materia orgánica.Todas estas condiciones son indeseables en un ambiente utilizado como recurso turístico y para provisión de agua potable

Hidrobiología del Embalse La Quebrada (Córdoba), Argentina : bacteriología y fitoplancton

El Embalse La Quebrada, localizado en Río Ceballos, a 32 Km al Noroeste de la ciudad de Córdoba, es el único reservorio para provisión de agua potable de aproximadamente 30.000 personas que viven en los alrededores, en las localidades de Río Ceballos, Unquillo y Mendiolaza. Desde 1997 se ha detectado un incremento en el proceso de eutroficación del lago, manifestándose principalmente en florecimientos de algas. En la actualidad el lago tiene periódicamente importantes blooms de Ceratium hirundinella (Dinofíceae), que se ven en la superficie del agua como manchones rojizos. También ha habido en los últimos años una interesante variación en dominancia entre Cianobacterias indicadoras de eutroficación, tales como las especies pertenecientes a los géneros Anabaena y Microcystis. En esta contribución se presentan datos varios correspondientes a muestreos efectuados no solamente en el Embalse sino además en sus dos tributarios.Los parámetros estudiados incluyen las más importantes características físico-químicas, microbiológicas y fitoplanctónicas que sirven para estimar calidad de aguaLos resultados indican que el Embalse podría ubicarse en un estadio mesotrófico, con marcada tendencia a eutrófico. Sus aguas se caracterizan por abundante productividad primaria, baja transparencia, procesos anaeróbicos en el hipolimnion que generan gases odoríferos, y recirculación de nutrientes con una alta carga de materia orgánica.Todas estas condiciones son indeseables en un ambiente utilizado como recurso turístico y para provisión de agua potable