International audience

peer reviewed | Un dosage sérologique des glycoprotéines associées à la gestation chez les caprins (caPAG), par la technique ELISA "sandwich" a été mis au point pour lediagnostic précoce de la gestation chez la chèvre naine de Guinée. Des anticorps anti-caPAG produits chez les lapins ont été biotinylés et titrés pour permettre cedosage dans le sérum de chèvres. Des échantillons de sang ont été collectés tous les 7 jours chez 6 chèvres après induction et synchronisation des chaleurs puissaillie pour doser la caPAG sérique. Les densités optiques ont été lues à 492 nm sur un lecteur automatique ELISA pour établie le profil de la caPAG.Le taux de caPAG augmente rapidement pendant le premier tiers de gestation pour atteindre un pic (117 ng/ml) vers le 91e jour puis baisse pour atteindre environ50 ng/ml le 121ème jour et reste plus ou moins stable jusqu’à la parturition où il chute progressivement pour atteindre environ 12,5 ng/ml trois semaines après.Cependant ce taux reste encore élevé dans la circulation maternelle 3 semaines après la parturition. La PAG caprine est détectable dans le sérum par cettetechnique à partir du 28ème jour de gestation avec une sensibilité de 100 %. Le 21ème jour, la sensibilité est faible (66,7 %). Ce test offre donc une alternativepratique au laboratoire, précoce et fiable pour le diagnostic de la gestation à partir du jour 28 après insémination chez la chèvre naine de Guinée.

peer reviewed | Un dosage sérologique des glycoprotéines associées à la gestation chez les caprins (caPAG), par la technique ELISA "sandwich" a été mis au point pour le diagnostic précoce de la gestation chez la chèvre naine de Guinée. Des anticorps anti-caPAG produits chez les lapins ont été biotinylés et titrés pour permettre ce dosage dans le sérum de chèvres. Des échantillons de sang ont été collectés tous les 7 jours chez 6 chèvres après induction et synchronisation des chaleurs puis saillie pour doser la caPAG sérique. Les densités optiques ont été lues à 492 nm sur un lecteur automatique ELISA pour établie le profil de la caPAG. Le taux de caPAG augmente rapidement pendant le premier tiers de gestation pour atteindre un pic (117 ng/ml) vers le 91e jour puis baisse pour atteindre environ 50 ng/ml le 121ème jour et reste plus ou moins stable jusqu’à la parturition où il chute progressivement pour atteindre environ 12,5 ng/ml trois semaines après. Cependant ce taux reste encore élevé dans la circulation maternelle 3 semaines après la parturition. La PAG caprine est détectable dans le sérum par cette technique à partir du 28ème jour de gestation avec une sensibilité de 100 %. Le 21ème jour, la sensibilité est faible (66,7 %). Ce test offre donc une alternative pratique au laboratoire, précoce et fiable pour le diagnostic de la gestation à partir du jour 28 après insémination chez la chèvre naine de Guinée.

Modern varieties developed under conventional plant breeding programs do not always perform well under organic and low-input growing conditions. Therefore, organic farmers need varieties adapted to variable environmental conditions. This means emphasis on traits such as nutrient uptake and use efficiency, good weed suppression ability and disease resistance and can be achieved via extended genetic diversity within the varieties: variety mixtures and populations of self-pollinating crops. The aim of the present study was to review published scientific literature about importance and research results on this topic. Scientific articles about the necessity of such studies and results of investigations performed in different countries have been studied. The main results show that variety mixtures have advantages in terms of disease control and yield stabilization and performance of mixtures may be affected by various factors – choice of components and its number, interactions between plants of components, manner of the mixing and growing technology. Depending on parental material, populations contain greater genetic diversity than variety mixtures. There are trends observed in the studies that yield of populations increased over generations and they are more stable than modern varieties, but there is no evidence that they would be significantly more productive. This research direction has recently become topical and is not sufficiently widely covered in the world agricultural science. The obtained results are inconsistent.

Since the middle of the last century rapid intensification of agricultural production systems has resulted in dramatic increase in fertilizer consumption as fertilizer has been considered as one of the most important factors for increased yields. However, not all the nutrient ions in a fertilizer applied to soil are taken up by crops, thus certain amount of the applied fertilizer is lost from agricultural fields leading to increases in nitrogen surplus, nitrogen losses to the environment and harmful impacts on biodiversity, air and water quality. This study aims to focus on crop fertilisation planning which is based on the knowledge of physical and chemical properties of soil and involves performing soil tests, designing a fertilisation plan and its practical implementation as well as calculating the balance of N, and to evaluate crop fertilisation planning as a tool for achieving balanced economic and environmental benefits in crop farming, which play an important role in efficient farming. In this study, the authors have analysed current situation in Latvia regarding requirements for fertilization planning in crop farms and have assessed potential costs and benefits from fertilisation planning. The research finds out that total cost of introducing of fertilisation planning ranges from 34 to 22 EUR haE-1, however, fertilisation planning is a neutral measure where costs are compensated by savings from N inputs which ranges from 10 to 40 kg N haE-1.Fertilisation planning generates environmental benefits, i.e. – reduces direct N2 O emissions from agricultural soils by 47 – 187 kg CO2eq haE-1 through reduced N fertilizer inputs.

Liming soils make both direct and indirect effects on greenhouse gas (GHG) emissions. If raising the pH of soil, the amount of N2 O emissions in the result of nitrification decreases; therefore, it is important to perform also maintenance liming if applying nitrogen fertilisers. Liming acidic soils contributes to the absorption of nutrients supplied by means of fertilisers by plants, limits the spread of plant diseases, forms better soil moisture and air regimes for plants, improves the structure of soil and activates microorganisms. The aim of this study was to assess liming effect on nitrogen use efficiency and nitrogen oxide emissions in crop farming. To achieve the aim, this study proceeds in two stages: 1) to analyse the scientific literature on the liming effect on nitrogen use efficiency and nitrogen oxide emissions in other countries, as a few such research studies are available in Latvia; 2) to calculate potential gains and losses from liming acid soils in order to examine the real situation concerning liming and its effects on the economy of farms. The research finds out that at the farm level in Latvia liming gives a positive economic effect (41.6 EUR haE-1) however, it is essential for maintaining soil fertility, increasing yields, and presumably for more efficient circulation of nitrogen, which decreases nitric oxide emissions.

The aim of this review was to summarize available bibliography on the possible applications of high pressure processing in dairy industry, the effect of this non-thermal treatment on bacterial microflora and milk constituents. Traditional thermal treatments applied to milk processing lower nutritional quality because many nutrients are heat labile. To overcome this problem, several non-thermal processing technologies including high hydrostatic pressure (HHP) processing have been developed. Pressures between 400 and 600 MPa inactivate microorganisms including food-borne pathogens; however, high pressure (HP) injured bacteria in milk during storage can recover. All enzymes are inactivated only at pressures of 800 MPa. During HHP the casein micelle size decreases, whey proteins are denaturated, the level of free fatty acids increases. These characteristics indicate that for better understanding and application of HPP in dairy industry research should be done to offer the numerous practical applications to produce microbially safe, minimally processed dairy products with improved performances, and to develop novel dairy products of high nutritional and sensory quality and increased shelf life.

The aim of this study was to investigate amino acid content, biological value and dietary fibre content of conventional and organic pea (Pisum sativum L.) and buckwheat (Fagopyrum esculentum M.) flours. Results showed that pea flours contained high amounts of aspartic acid, threonine, serine, glycine, alanine, valine, isoleucine, leucine, tyrosine, phenylalanine, histidine, lysine and arginine while glutamic acid, proline, methionine and tryptophan were found in similar or smaller amounts comparing with wheat flour. The differences of various amino acids between conventional and organic pea flours were insignificant. The content of aspartic acid, threonine, serine, glycine, alanine, valine, histidine, lysine and arginine was high in buckwheat flours in comparison with wheat flour. There were significant (p is less than 0.05) differences in the individual amino acid contents across buckwheat flours. Significant (p is less than 0.05) variation existed in the content of essential amino acids among samples, whereas the results concerning the proportion of essential amino acids in total amino acids showed insignificant (p is greater than 0.05) differences between pea flours and buckwheat flours (34.80 – 35.77% and 29.96 – 33.90% respectively). The highest content of lysine was found in pea flours, and it formed about 23% of essential amino acids content. For pea flours the total dietary fibre amount varied between 15.28 g 100 gE-1 for conventional and 27.24 g 100 gE-1 for organic pea flour. Pea and buckwheat flours could be characterised as a good source of dietary fibre with significantly (p is less than 0.05) higher content of total dietary fibre comparing to wheat flour.

The diversity of non-starter lactic acid bacteria in raw, pasteurised milk and maturated Swiss type cheese was tested. The aim of the present study was to analyse the concentrations and representatives of non-starter lactic acid bacteria in raw milk and to evaluate the changes of their concentrations and representatives during pasteurisation of cheese milk and Swiss-type cheese production. The analysis carried out in the study showed a variation in the microbial composition and quantity of raw milk. The most frequently isolated lactobacilli were found at low level in raw milk (mean 27.5×104 CFU mLE-1) and the most frequently identified species were Lactobacillus brevis and Lactobacillus paracasei. The microflora of raw and pasteurised milk is similar analysing lactic acid bacteria representatives in the samples. Lactobacillus brevis and Lactobacillus paracasei were detected in the same samples in raw milk, pasteurised milk and maturated cheese. Our study showed that lactic acid bacteria concentration was quite low in pasteurised milk (1-12 CFU mLE-1), but they grow rapidly in cheese during ripening reaching 1.1-1.8*106 CFU gE-1. The present study has shown that NSLAB in Swiss-type cheese mainly derive from raw milk, and only a few strains survive the processing conditions and grow during ripening.

Kvass is an aromatic soft drink which in a form of powder could be used in dairy or bakery products, or sugar confectionary to expand the diversity of flavours. Spray drying is one of the techniques used for producing powders; however, liquids with high sugar content become sticky during drying process and need additional drying aids to increase glass transition temperature and improve powder stability. The aim of this research was to evaluate the characteristics of dry naturally fermented kvass. Maltodextrin was used in 50, 40 and 25% quantity to kvass dry matter in order to aid the spray drying of naturally fermented non-pasteurised, non-filtered bread kvass. Spray drying of 8 l naturally fermented kvass returned approximately 500 g dry naturally fermented kvass powder with a light brown colour, a pronounced aroma of rye bread and moisture content of 7 ± 0.1%. Microstructure analysis of the spray dried naturally fermented kvass showed irregularly spherical shaped particles, having many shrinkages, breakages and dents on the surface in general. Total viable microorganism count in dry naturally fermented kvass powder was within the recommended levels, traces of lactic acid bacteria were found in all samples. The presence of Bacillus amyloliquefaciens was established in dry naturally fermented kvass powders, with possible contamination from spray dryer.