Ontogeny and nutritional programming of the hepatic growth hormone-insulin-like growth factor-prolactin axis in the sheep

The liver is an important metabolic and endocrine organ in the fetus but the extent to which its hormone receptor (R) sensitivity is developmentally regulated in early life is not fully established. We, therefore, examined developmental changes in mRNA abundance for the growth hormone (GH) and prolactin (PRL) receptors (R) plus insulin-like growth factor (IGF)-I and –II and their receptors. Fetal and postnatal sheep were sampled at either 80, or 140 days gestation, 1, 30 days or six months of age. The effect of maternal nutrient restriction between early to mid (i.e. 28 to 80 days gestation, the time of early liver growth) gestation on gene expression was also examined in the fetus and juvenile offspring. Gene expression for the GHR, PRLR and IGF-IR increased through gestation peaking at birth, whereas IGF-I was maximal near to term. In contrast, IGF-II mRNA decreased between mid and late gestation to increase after birth whereas IGF-IIR remained unchanged. A substantial decline in mRNA abundance for GHR, PRLR and IGF-IR then occurred up to six months. Maternal nutrient restriction reduced GHR and IGF-IIR mRNA abundance in the fetus, but caused a precocious increase in the PRLR. Gene expression for IGF-I and –II were increased in juvenile offspring born to nutrient restricted mothers. In conclusion, there are marked differences in the developmental ontogeny and nutritional programming of specific hormones and their receptors involved in hepatic growth and development in the fetus. These could contribute to changes in liver function during adult life.

Traditional part-time grazing: a more sustainable sheep milk and cheese production in the Basque Country

[EN] The concept of sustainability when referring to food production rests, in general, on 3 main aspects: 1) respect for the environment; 2) economic and social benefits for all involved in production; and 3) production of sufficient quantity of quality food at an accessible price. In this contribution we focus on the main aspects of the traditional sheep's milk and cheese production (under the Denomination of Origin Idiazabal Cheese) in the Basque Country that contribute primarily to its sustainability. It is based on the local latxa or carranzana breeds of sheep, adapted to the mountainous terrain. The sheepherder takes advantage of local resources to reduce management costs by combining indoor dry forage and concentrates with outdoor grazing throughout lactation, according to local pasture availability, and thus avoiding having to buy large amounts of feed. This system facilitates recycling of manure, fertilising pastures and forest at the same time. Use of local breeds helps maintain biodiversity of sheep breeds. Cheese is produced industrially (44.5% of the total cheese produced in 2008) from milk of many flocks, or artisanally (38.3%) by the sheepherders with the milk from their own flocks. Transforming their own milk into cheese is advantageous for the following reasons: 1) higher economic returns as compared to selling the milk to cheese factories because cheese price directly sold to consumers is more competitive than industrial cheese sold in supermarkets; 2) increases the value of women's work (over 80% of the cheese makers are women) in the community and their self-esteem; 3) it creates rural jobs and contributes to rural development; 4) we have demonstrated both with experimental and commercial flocks that part-time grazing allows the sheepherder to obtain high yields of milk, and cheese, of high nutritional and functional quality. Currently a less sustainable, intensive sheep's milk production with foreign, imported breeds kept indoors constantly is gaining favour among milk producers because of its perceived higher economic profitability.

Molecular detection of Brucella melitensis in sheep and goat milk in Iran

Purpose: To detect Brucella melitensis in the milk of reared sheep and goats from Isfahan and Shahrekord regions, Iran. Methods: A total of 225 milk samples (sheep = 125; goat = 100) were collected from Isfahan and Shahrekord regions, Central Iran. Polymerase chain reaction (PCR) was used to detect the presence of B. melitensis in the milk following standard procedures. Results: From 225 milk samples, 20 (8.9 %) were positive for B. melitensis. Out of 125 sheep milk, 12 (9.6 %) had B. melitensis, and of these, 8 (66.6 %) were milk collected from Shahrekord and 4 (33.3 %) from Isfahan region. On the other hand, out of 100 goat milk samples, 18 (18 %) were positive for B. melitensis, out of which 10 (55.5 %) were from Shahrekord and 8 (44.4 %) from Isfahan. Conclusion: The findings show that B. melitensis is present in a significant proportion of caprine and ovine milk in a section of Iran.

Coarser wool is not a necessary consequence of sheep aging: allometric relationship between fibre diameter and fleece-free liveweight of Saxon Merino sheep

The mean fibre diameter (MFD) of wool is the primary determinant of price, processing performance and textile quality. This study determines the primary influences on MFD as Saxon Merino sheep age, by allometrically relating MFD to fleece-free liveweight (FFLwt). In total, 79 sheep were grazed in combinations of three stocking rates and two grazing systems (GS: sheep only; mixed with Angora goats) and studied over 3 years. Measurements were made over 14 consecutive periods (Segments), including segments of FFLwt gain or FFLwt loss. Using shearing and liveweight records and dye-bands on wool, the FFLwt and average daily gain (ADG) of each sheep were determined for each segment. The mean and range in key measurements were as follows: FFLwt, 40.1 (23.1 to 64.1) kg; MFD, 18.8 (12.7 to 25.8) μm. A random coefficient restricted maximum likelihood (REML) regression mixed model was developed to relate the logarithm of MFD to the logarithm of FFLwt and other effects. The model can be written in the form of ${\rm MFD}\,{\equals}\,\rkappa \left( {{\rm GS,}\,{\rm A}{\rm ,}\,{\rm Segment}{\rm .Plot,}\,{\rm Segment,}\,{\rm ADG}} \right){\times}{\rm FFLwt}^{{\left( {\ralpha \left( {{\rm GS}} \right){\plus}\rbeta \left(\rm A \right){\plus}\rgamma \left( {{\rm Segment}{\rm .Plot}} \right)} \right)}} $ , where $\ralpha \left( {{\rm GS}} \right)\,{\equals}\,\;\left\{ {\matrix{\!\! {0.32\left( {{\rm SE}\,{\equals}\,{\rm 0}{\rm .038}} \right)\,{\rm when}\,{\rm sheep}\,{\rm are}\,{\rm grazed}\,{\rm alone}} \hfill \cr \!\!\!\!{0.49\left( {{\rm SE}\,{\equals}\,{\rm 0}{\rm .049}} \right)\,{\rm when}\,{\rm sheep}\,{\rm are}\,{\rm mixed}\,{\rm with}\,{\rm goats}} \hfill \cr } } \right.$ β(A) is a random animal effect, γ(Segment.Plot) a random effect associated with Segment.plot combinations, and κ a constant that depends on GS, random animal effects, random Segment.plot combination effects, Segment and ADG. Thus, MFD was allometrically related to the cube root of FFLwt over seasons and years for sheep, but to the square root of FFLwt for sheep grazed with goats. The result for sheep grazed alone accords with a primary response being that the allocation of nutrients towards the cross-sectional growth of wool follicles is proportional to the changes in the skin surface area arising from changes in the size of the sheep. The proportionality constant varied systematically with ADG, and in sheep only grazing, was about 5 when sheep lost 100 g/day and about 6 when sheep gained 100 g/day. The proportionality constant did not systematically change with chronological age. The variation in the allometric coefficient between individual sheep indicates that some sheep were more sensitive to changes in FFLwt than other sheep. Key practical implications include the following: (a) the reporting of systematic increases in MFD with age is likely to be a consequence of allowing sheep to increase in size during shearing intervals as they age; (b) comparisons of MFD between sheep are more likely to have a biological basis when standardised to a common FFLwt and not just to a common age;

Characterization of protection afforded by a bivalent virus-like particle vaccine against bluetongue virus serotypes 1 and 4 in sheep

BACKGROUND Bluetongue virus (BTV) is an economically important, arthropod borne, emerging pathogen in Europe, causing disease mainly in sheep and cattle. Routine vaccination for bluetongue would require the ability to distinguish between vaccinated and infected individuals (DIVA). Current vaccines are effective but are not DIVA. Virus-like particles (VLPs) are highly immunogenic structural mimics of virus particles, that only contain a subset of the proteins present in a natural infection. VLPs therefore offer the potential for the development of DIVA compatible bluetongue vaccines. METHODOLOGY/PRINCIPAL FINDINGS Merino sheep were vaccinated with either monovalent BTV-1 VLPs or a bivalent mixture of BTV-1 VLPs and BTV-4 VLPs, and challenged with virulent BTV-1 or BTV-4. Animals were monitored for clinical signs, antibody responses, and viral RNA. 19/20 animals vaccinated with BTV-1 VLPs either alone or in combination with BTV-4 VLPs developed neutralizing antibodies to BTV-1, and group specific antibodies to BTV VP7. The one animal that showed no detectable neutralizing antibodies, or group specific antibodies, had detectable viral RNA following challenge but did not display any clinical signs on challenge with virulent BTV-1. In contrast, all control animals' demonstrated classical clinical signs for bluetongue on challenge with the same virus. Six animals were vaccinated with bivalent vaccine and challenged with virulent BTV-4, two of these animals had detectable viral levels of viral RNA, and one of these showed clinical signs consistent with BTV infection and died. CONCLUSIONS There is good evidence that BTV-1 VLPs delivered as monovalent or bivalent immunogen protect from bluetongue disease on challenge with virulent BTV-1. However, it is possible that there is some interference in protective response for BTV-4 in the bivalent BTV-1 and BTV-4 VLP vaccine. This raises the question of whether all combinations of bivalent BTV vaccines are possible, or if immunodominance of particular serotypes could interfere with vaccine efficacy.

Characterization of the immune response induced by a commercially available inactivated bluetongue virus serotype 1 vaccine in sheep

The protective immune response generated by a commercial monovalent inactivated vaccine against bluetongue virus serotype 1 (BTV1) was studied. Five sheep were vaccinated, boost-vaccinated, and then challenged against BTV1 ALG/2006. RT-PCR did not detect viremia at any time during the experiment. Except a temperature increase observed after the initial and boost vaccinations, no clinical signs or lesions were observed. A specific and protective antibody response checked by ELISA was induced after vaccination and boost vaccination. This specific antibody response was associated with a significant increase in B lymphocytes confirmed by flow cytometry, while significant increases were not observed in T lymphocyte subpopulations (CD4(+), CD8(+), and WC1(+)), CD25(+) regulatory cells, or CD14(+) monocytes. After challenge with BTV1, the antibody response was much higher than during the boost vaccination period, and it was associated with a significant increase in B lymphocytes, CD14(+) monocytes, CD25(+) regulatory cells, and CD8(+) cytotoxic T lymphocytes.

Effect of Preventive Chlamydia abortus Vaccination in Offspring Development in Sheep Challenged Experimentally

Ovine enzootic abortion, caused by Chlamydia abortus, leads to important economic losses worldwide. In addition to reproductive failures, infection may impact lamb growth during the first weeks after birth, yet this effect has not been well characterized. Vaccination can help to control the disease but variable efficacy values have been described, possibly related with factors associated with the host, the vaccine, the parameter used for efficacy determination and the challenge conditions. In this context, we evaluated the efficacy of an inactivated standard commercial vaccine and a 1/2 diluted dose in pregnant sheep challenged with C. abortus by examining multiple indicators ofvaccine effect (including incidence of reproductive failures, bacterial excretion, and evolution of weight gain of viable lambs during the first month of life). Three groups of ewes [control non-vaccinated, C (n = 18); vaccinated with standard dose, SV (n = 16) and vaccinated with 1/2 dose, DV (n = 17)], were challenged approximately 90 days post-mating and tested using direct PCR (tissue samples and vaginal swabs) and ELISA (serum) until 31 days post-reproductive outcome. There were not significant differences in the proportions of reproductive failures or bacterial shedding after birth/abortion regardless the vaccination protocol. However, a beneficial effect of vaccination on offspring growth was detected in both vaccinated groups compared with the controls, with a mean increase in weight measured at 30 days of life of 1.5 and 2.5 Kg (p = 0.056) and an increase in the geometric mean of the daily gain of 8.4 and 9.7% in lambs born from DV and SV ewes compared to controls, respectively. Our results demonstrate the effect of an inactivated vaccine in the development of the offspring of C. abortus-infected ewes at a standard and a diluted dose, an interesting finding given the difficulty in achieving sufficient antigen concentration in the production of EAE-commercial vaccines.

Proposal to minimize the difficulty of recording abortion data in sheep

Background: The most frequent viral diseases which can cause abortion in sheep are Blue tongue, Border disease virus, Cache Valley fever and Schmallenberg virus. The diagnosis of abortion, namely virus-induced represents a challenge to field clinicians, since clinical signs presented by the dam are discrete, non-specific and variable (Agerhom et al., 2015). On the other hand, while some foetuses reveal characteristic and visible malformations, others do not reveal any lesions. In face of it, definitive diagnosis requires an appropriate history collection, as well as sending fresh samples, namely abortion material, foetus, placenta and umbilical cord, to a specialty laboratory, to obtain a precise diagnosis. Objectives: The authors suggest a registration method of all mandatory data, in order to further assist the diagnosis of viral diseases at the laboratories, including the most frequent congenital malformations reported in sheep abortions. Methods: Abortion samples of suspected viral origin were collected and all data were registered, in worktables optimized for this purpose. Results: The authors document, using macroscopic figures lesions of malformations in abortions, emphasizing the frequency and the importance of documenting each case, proposing practical and effective worktables to assist the fieldwork. Conclusions: Field clinician’s awareness of the importance of early detection of viral diseases causing abortion outbreaks stimulates a proper data collection for each case of abortion, in order to contribute to a precise diagnosis and posterior consistent epidemiological studies, which may allow diminishing of economic losses.

Antimicrobial activity of Brazilian propolis extracts for Staphylococcus aureus of sheep and goats mastitis origin

Twenty-four S. aureus isolates were analysed. From those, 22 were isolated from milk of goats and sheep with clinical and subclinical mastitis, from the region of Vale do São Francisco in the Brazilian Sertão and S. aureus ATCC 25923 plus a MRSA strain were added. Alcoholic extracts were produced from several batches of green, red and brown propolis consisting of 300 g of raw propolis in 700 mL of 70 % ethanol. Four genes related to antimicrobial resistance were assessed: blaZ that determines the resistance to β-lactam antibiotics, and genes icaA, icaD and bap that influence the production of biofilm. For the tests of susceptibility to different types of propolis the microdilution method was used, in triplicate, and dilutions between 0.003672 and 15% were tested, 70 % ethanol consisted of a negative control. The gene blaZ was found in 15 isolates; icaA gene was present in 3 isolates, icaD gene in 2 and bap gene was detected in 6 isolates. All the propolis tested exhibited antimicrobial activity, ranging from 44 to 100 % of susceptible isolates depending on different propolis batches. According to the results of this experiment the green and red propolis appear to have better antimicrobial activity than the brown variety.

Antibiofilm activity of Brasilian propolis extracts against Staphylococcus aureus producers isolated from goat and sheep mastitic milk

The aim of this study was to investigate the action of inhibiting S. aureus biofilm formation, and the ability to eliminate formed biofilm, by alcoholic extracts of green, red and brown propolis from Brazil. Ten isolates of S. aureus have been tested, 8 field isolates, 1 MRSA and 1 ATCC 25923, by microplate quantitative method. For the evaluation of inhibitory action, the isolates were inoculated, in triplicate, in TSB 1% glucose in the presence of green (1), red (2) and brown (4) propolis extracts. Biofilm formation was evaluated by optical reading, compared to a negative control consisting of a mixture of TSB and extract. For biofilm elimination assay, extracts were added to plates with 24h cultures of the same isolates. Assays were repeated three times on three different days. Eight out of the 10 isolates produced less biofilm in the presence of the green propolis extracts, so the inhibitory effect is 80%. Brown propolis extracts inhibited the formation of biofilm in 10% to 70% of the isolates and the red extracts in 30% to 80%. Regarding the biofilm elimination activity, green propolis extract was positive for 9 out of the 10 isolates (90%), the brown propolis extracts were positive for 0% to 100% isolates and red extracts for 0% to 10% isolates.

Thermoregulatory response in hair sheep and shorn wool sheep

This study’s main goal was to evaluate the thermoregulatory responses velocity through the variation of rectal temperature (RT), related to the thermolytic pathways, respiratory rate (RR) and sweating rate (SR) among different sheep breeds. Ninety female sheep, eighteen of each breed: Santa Ines and Morada Nova (Brazilian hair breeds), Texel, Suffolk and Ile de France (wool breeds) were challenged during three non-consecutive summer days (22◦42′S, 47◦18′W, and 570m of altitude, maximum air temperature of 33.5◦C, average relative humidity of 52±6.9%). The physiological variables were registered at 0800h (T1), 1300 h (T2: after 2 h of shade rest), 1400 h (T3) (after one hour of sun exposure) and in the shade at 1415 h (T4), 1430 h (T5), 1445 h (T6) and 1500 h (T7) and a thermotolerance index (TCI) was calculated as (10-(T7 to T4)-T1). The statistical analysis was performed by a mathematical model including the fixed effects of breeds and time frames, and the interaction between these effects, besides random effects such as animal and day. The Santa Ines breed presented the lowest RT after sun exposure (39.3 ± 0.12 ◦ C; P < 0.05) and it was the only one to recover morning RT 60 min after heat stress (38.7 and 38.9 for 1300 h and 1500 h; P > 0.05). Hair breeds presented RR lower (P < 0.05) than wool breeds. Although thick wool or hair thickness differs among and within hair and wool breeds (P < 0.05), SR did not differ among breeds and time (227.7 ± 16.44 g m−2 h−1 ; P > 0.05). The thermotolerance index did not differ among breeds, but it showed similar response (P > 0.05) 45 min or 1 h of shade after sun exposure. One week post shearing is not enough to wool breeds present to show thermotolerance similar to hair breeds.

Cryopreservation of Sheep Produced Embryos – Current and Future Perspectives

Due to economical and scientific limitations, sheep embryo reproductive technologies are less commercially applied than in other animal species. However, it is very clear that, in the near future, those techniques are expected to have a central role in animal production as a consequence of genetic and reproductive demands. One drawback is that results obtained after sheep embryo cryopreservation are unattractive for commercial purposes. It is expected that a successful cryopreservation of sheep embryos can push forward all other reproductive biotechnologies in this species, such as multiple ovulation and embryo transfer (MOET), artificial insemination, or in vitro production of embryos. This paper tries to discuss the current and future perspectives of cryopreservation of in vivo- and in vitro-produced sheep embryos concerning advantages and limitations for its practical use and possible solutions for improving methods to allow a higher survival rate of cryopreserved embryos.

Intake, digestibility, and nitrogen balance of rations containing different levels of murumuru meal in sheep diets.

A pesquisa objetivou estudar o potencial de utilização da torta de murumuru (Astrocaryum murumuru var. murumuru, M art.) (TM) em dietas de ovinos, em substituição à gramínea Mombaça (Panicum maximum Jacq) com teores crescentes. Realizou-se ensaio metabólico, com 20 ovinos machos, castrados, na Embrapa Amazônia Oriental, Belém, Pará, durante 26 dias. O delineamento foi inteiramente casualizado, em cinco dietas e quatros repetições. TM0: 100% de gramínea; TM10: 10% de TM e 90% de gramínea; TM20: 20% de TM e 80% de gramínea; TM40: 40% de TM e 60% de gramínea e TM60: 60% de TM e 40% de gramínea. Foram avaliados o consumo e o coeciente de digestibilidade aparente da matéria seca (CMS e CDMS), matéria orgânica (CMO e CDMO), proteína bruta (CPB e CDPB), bra em detergente neutro (CFDN e CDFDN), bra em detergente ácido (CFDA e CDFDA), extrato etéreo (CEE e CDEE), celulose (CCEL e CDCEL), hemicelulose (CHEM e CDHEM) e balanço de nitrogênio (BN) das dietas experimentais. O CMS, CMO, CMM, CPB, CFDN e CFDA apresentaram efeito linear decrescente em função dos teores de substituição da gramínea Mombaça por TM na dieta. O CEE e o CLIG apresentaram efeitos quadráticos em função dos teores de substituição da TM na dieta. O CDMS, CDMO e CDHEM tiveram efeitos lineares crescentes, entre TM0 e TM60. O CDEE, CDFDN, CDFDA e CDCEL apresentaram efeito quadrático, com teores de substituição ótimos de 56,65%, 41%, 31,33% e 27,46%, respectivamente. O balanço de nitrogênio apresentou efeito linear negativo no intervalo de inclusão de 0% a 60% de torta. Conclui-se que a torta de murumuru constitui alternativa para a suplementação alimentar de ruminantes, em substituição à gramínea Mombaça, pois proporciona aumento na digestibilidade dos nutrientes por ovinos. Entretanto, deve-se respeitar um limite de inclusão, considerando-se que a partir de 27,46%, 31,33%, 41% e 56,65% de substituição ocorrem decréscimos, respectivamente da CDCEL, CDFDA, CDFDN e CDEE, embora não ocorra valor negativo para o balanço de nitrogênio.

Diagnosis of subclinical mastitis in Santa Inês and Morada Nova sheep in southeastern Brazil

2016

Genotypic profile of Pantanal creole sheep regarding susceptibility or resistance to scrapie.

The objective of this work was to determine the genotypic profile specific to scrapie in codons 136, 154, and 171 of the PRNP gene of the Pantanal creole sheep. Genomic DNA was extracted from blood samples collected from 66 sheep, and the regions of interest on the DNA strand were amplified by PCR. Five haplotypes were identified: ARR, alanine, arginine, arginine; ARQ, alanine, arginine, glutamine; AHQ, alanine, histidine, glutamine; ARH, alanine, arginine, histidine; and VRQ, valine, arginine, glutamine. The most common genotypes were ARQ/ARQ (27%) and ARR/ARQ (24%). The genotypic profile of the Pantanal creole sheep shows low to moderate susceptibility.