Effect of melatonin treatment on reproductive activity and immune response in Sarda sheep breed

The aims of the present thesis were to evaluate the effect of melatonin treatment (MELOVINE subcutaneous implant 18 mg melatonin) in different aspects of livestock of Sarda sheep breed (considering season, lactating periods, male replacement during mating perdiod, puberty, different melatonin receptor genotype, milk yield and mammary immune system). This study was conducted in different farms located in Sardinia and similar for raising condition and animals managment, involving a great number of sheep. The data confirmed that melatonin is able to advance reproductive recovery in Sarda sheep breed in spring. Furthermore, the most suitable time to perform the melatonin treatment for the best response to the male effect is April-May. Melatonin treatment should be performed 3 or 4 months after lambing, in order to obtain optimal reproductive results. A weekly substitution of the males and their treatment with melatonin guarantees a better reproductive efficiency both in the adult ewes and in the ewe lambs. Another interesting conclusion is that treatment with melatonin in lactating sheep does not change the quantity and quality of milk and decreases the number of somatic cells, suggesting that this molecule can preserve health of the mammary gland. In conclusion, this thesis has provided many results directly applicable in Sarda sheep farms in order to improve reproductive efficiency, furthermore can give a new starting point to the development of research

Reproductive activity in sheep with different lambing period treated with melatonin in April

The object was to evaluate the effect of melatonin treatment on the advance in April of the reproductive resumption in Sarda breed sheep with different lambing period. For the research two farms, located in North Sardinia between 39° and 40° N, were chosen. In each farm, 120 lactating ewes were selected: 30 lambed between October 20th and November 20th (group 1); 30 lambed between December 1st and 30th (group 2); 30 lambed between January 1st and 30th; 30 lambed between February 1st and 28th (group 4). In each farm, each group of 30 animals was divided into two subgroups of 15 animals (M and C). On April 1st, in each farm, the animals of the M subgroups were treated with a implant containing 18 mg melatonin. The subgroups C were kept as control. The lambing dates and the number of newborn lambs were recorded until 220 days after ram introduction. In treated animals greatest fertility (P<0.01) and lowest distance in days from male introduction to lambing (P<0.01) were recorded. The best reproductive performances were found in the group 1 and 2 compared to the other two groups (P<0.01).The present research shows that melatonin treatment should be made 3 or 4 months after lambing, in order to obtain optimal results

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&ndash;6 years old), body condition score (BCS) (range 2.0&ndash;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 &lt; 0.01) and the shortest distance between ram introduction to lambing (p &lt; 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

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

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

Detection of Polymorphisms in the MTNR1A Gene and Their Association with Reproductive Performance in Awassi Ewes

The economy in Mediterranean areas is tightly linked to the evolution of the sheep-farming system; therefore, improvement in ewe’s reproductive performance is essential in the developing countries of this area. MTNR1A is the gene coding for Melatonin receptor 1 (MT1), and it is considered to be involved in the reproductive activity in sheep. The aims of this study were: (1) identifying the polymorphisms from the entire MTNR1A coding region and promoter in Lebanese Awassi sheep flocks, and (2) investigating the association between the found polymorphisms and the reproductive performance, assessed as lambing rate, litter size, and days to lambing (DTL). The study was conducted in two districts of Lebanon, where 165 lactating ewes, aged 5.2 ± 1.5 years, with body condition score (BCS) 3.3 ± 0.4, were chosen and exposed to adult and fertile rams. From 150 to 220 days after ram introduction, lambing dates and litter sizes were registered. This study provided the entire coding region of the MTNR1A receptor gene in the Awassi sheep breed. Thirty-one single nucleotide polymorphisms (SNPs) were detected, five of which were missense mutations. The H2, H3, and H4 haplotypes were associated with lower DTL (p &lt; 0.05), as well as the SNPs rs430181568 and rs40738822721, named from now on SNP20 and SNP21, respectively. These SNPs were totally linked and can be considered as a single marker. The ewes carrying the C allele at both these polymorphic sites advanced their reproductive recovery (p &lt; 0.05). These results are essential for improving reproductive management and obtaining advanced lambing in Awassi ewes

Detection of Polymorphisms in the <i>MTNR1A</i> Gene and Their Association with Reproductive Performance in Awassi Ewes

The economy in Mediterranean areas is tightly linked to the evolution of the sheep-farming system; therefore, improvement in ewe’s reproductive performance is essential in the developing countries of this area. MTNR1A is the gene coding for Melatonin receptor 1 (MT1), and it is considered to be involved in the reproductive activity in sheep. The aims of this study were: (1) identifying the polymorphisms from the entire MTNR1A coding region and promoter in Lebanese Awassi sheep flocks, and (2) investigating the association between the found polymorphisms and the reproductive performance, assessed as lambing rate, litter size, and days to lambing (DTL). The study was conducted in two districts of Lebanon, where 165 lactating ewes, aged 5.2 ± 1.5 years, with body condition score (BCS) 3.3 ± 0.4, were chosen and exposed to adult and fertile rams. From 150 to 220 days after ram introduction, lambing dates and litter sizes were registered. This study provided the entire coding region of the MTNR1A receptor gene in the Awassi sheep breed. Thirty-one single nucleotide polymorphisms (SNPs) were detected, five of which were missense mutations. The H2, H3, and H4 haplotypes were associated with lower DTL (p p < 0.05). These results are essential for improving reproductive management and obtaining advanced lambing in Awassi ewes

Production of farmstead lactose-free Pecorino di Osilo and ricotta cheeses from sheep’s milk

The present work was aimed to define and validate farmstead production of lactose- free Pecorino di Osilo cheese, fresh ricotta cheese, and salted and smoked ricotta cheese (Ricotta mustia). The enzymatic activity of the commercial preparation containing lactase (1.1 g/mL), preliminarily tested using a spectrophotometric titration, showed activity equal to 4950±40 neutral lactase unit/g. The amount of lactase required to obtain the lactose-free milk was then established in triplicate laboratory trials, by adding the enzyme at concentrations of 0.7, 0.9 and 1.1 g/L in flasks containing 160 mL of raw sheep’s milk. Samples were incubated under conditions expected during milk storage and cheese-making. The residual lactose content in milk was determined by enzymatic method. The addition of lactase at concentration of 1.1 g/L of milk reduced the lactose concentration below the limit of detection (LOD) of 0.06 g/L. The procedure was validated at a dairy farm, using three different batches of bulk raw sheep’s lactose-free milk that were transformed into Pecorino di Osilo cheese. The resulting whey was used to produce fresh ricotta and Ricotta mustia cheese. Raw milk and whey samples were always below lactose detection limit. The residual lactose was measured in Pecorino di Osilo cheese, after 24 hours and 30 days from production; in fresh ricotta cheese, after 48 hours; in Ricotta mustia cheese after 7 days. The determination of lactose content in cheese samples was conducted by a gas chromatography- flame ionization detection method, which showed a LOD and limit of quantification respectively of 1.8 and 5.6 mg/kg for cheese, and 1.35 and 4.2 mg/kg for both ricotta cheeses. The lactose concentration was always below the relevant LOD values in all samples. The mean concentration of galactose and glucose were respectively 13,000±2000 and 11,000±2000 mg/kg in fresh Pecorino di Osilo, 1100±300 and 1200±300 mg/kg in fresh ricotta, and 950±400 and 750±250 mg/kg in Ricotta mustia. The results of the present study showed that the production of farmstead lactose-free Pecorino di Osilo cheese and ricotta cheeses from raw sheep’s milk is easily achievable. The main issue for farmstead production of artisanal lactose-free products is the implementation of permanent procedures based on hazard-analysis and critical control principles aimed at guaranteeing the effectiveness of the process and at acquiring analytical evidences to demonstrate the fulfilment of law requirements for labelling

Lactation Characteristics in Alpine and Nera di Verzasca Goats in Northern Italy: A Statistical Bayesian Approach

In the last three decades, we assisted in a shift in the dairy product preferences in developed countries, with an increase in goat-derived products consumption. As already seen in the bovine sector, the diffusion of goat milk consumption has led to an abandonment of the local breeds in favor of the more productive cosmopolitan breeds, with an intense reduction in the livestock biodiversity. However, in several studies, it has been shown that local breeds present unique features such as a robust behavior towards the local climate and a high quality of their dairy products. This study aims to assess the differences between the basic lactation variables (milk yield, fat %, protein %, lactose % and somatic cell count) in the Alpine goat and the local breed Verzasca goat from a Bayesian point of observation. Results indicate that the Nera di Verzasca goat has overall lactation characteristics similar toa cosmopolite breed such as the Alpine goat, except for the milk daily yield reduced with respect to Alpine goats (1.68 ± 0.84 and 2.14 ± 1.03, respectively). Moreover, the Verzasca goat showed a tendency to maintain a lower level of somatic cell count along with lactation (798 ± 1734 and 1216 ± 2828, respectively). These findings help to increase the knowledge about the Italian local goat breeds and are important in the optic of biodiversity conservation