​Determination of Serogroup and Lytic Activities of Bacteriophages Isolated from Phage Plaques in Staphylococcus aureus Cultures Identified from Sheep Milk with Mastitis

Backgorund: Bacteriophages are closely related to the evolution and virulence of some important bacterial pathogens. Due to their highly significant roles in pathogenesis and virulence, S. aureus bacteriophages are frequently studied. Bacteriophages are grouped into two main categories depending on their life cycles. There are highly consistently lytic phages (virulent) and temperate phages. This study aimed to isolate bacteriophages and determine their phage serogroups from phage plaques in S. aureus cultures in order to show if they are lytic or lysogenic, the latter plays a major role in horizontal gene transfer. Methods: A total of 234 S. aureus isolates were recovered from milk samples from cases with gangrenous mastitis in sheep. Staphylococcal phages are determined based on the type and serogroup by PCR using specific primers. Result: Our study allowed us to determine serogroups of the isolated bacteriophages. Two phage stock samples included only one serogroup while the others included more than one phage serotypes and needed further purification Fa, L and D serogroups were not determined in the study. Present work revealed that all the isolated phages were temperate phages, which play a highly significant role in horizontal gene transfer.

The Role of Bovine and Non-Bovine Milk in Cardiometabolic Health: Should We Raise the “Baa”?

Although causality is yet to be confirmed, a considerable volume of research has explored the relationships between cow milk consumption, type II diabetes, and cardiovascular disease. Contrastingly, it has not been comprehensively examined whether milk of non-bovine origin can provide cardiometabolic protection. This narrative review outlines the marked differences in macronutrient composition, particularly protein and lipid content, and discusses how whole milk product (and individual milk ingredients) from different species could impact cardiometabolic health. There is some data, although primarily from compositional analyses, animal studies, and acute clinical trials, that non-bovine milk (notably sheep and goat milk) could be a viable substitute to cow milk for the maintenance, or enhancement, of cardiometabolic health. With a high content of medium-chain triglycerides, conjugated linoleic acid, leucine, and essential minerals, sheep milk could assist in the prevention of metabolic-related disorders. Similarly, albeit with a lower content of such functional compounds relative to sheep milk, goat and buffalo milk could be plausible counterparts to cow milk. However, the evidence required to generate nutritional recommendations for ‘non-bovine milk’ is currently lacking. Longer-term randomised controlled trials must assess how the bioactive ingredients of different species’ milks collectively influence biomarkers of, and subsequently incidence of, cardiometabolic health.

A rapid phage assay for detection of viable Mycobacterium avium subsp. paratuberculosis in milk

Paratuberculosis is an incurable gastroenteritis among ruminants that is promoted by Mycobacterium avium subsp. paratuberculosis (MAP), an acid-fast mycobacterium. To accelerate the detection of viable pathogen, a conventional (peptide mediated magnetic separation: PMS) and novel (phage-bead qPCR: PBQ) phage based assay was optimized. A superior limit of detection (LOD) of 10 MAP per 10 mL milk was suggested for PBQ compared to 100 cells/10 mL for PMS-phage assay. Via PBQ, viable MAP was found in 48.78% out 41 unpasteurized sheep and goat milk samples. Sheep milk samples (n = 29) that were tested by PMS-phage assay contained no viable MAP. The absence of viable MAP in milk collected from 21 of the recent sheep animals was also confirmed by PBQ after a 2-week gap. Although, the two phage assays comparably detected no viable MAP in the milk samples, MAP DNA and antibodies against MAP were recognized in milk and sera of some of these animals within two instances of sampling representing that some sheep animals were MAP shedders. In conclusion, PBQ and PMS-phage could be promising methods for the assessment of MAP viability in milk samples. However, PBQ was privileged over the PMS-phage assay due to the lower LOD, rapidity, higher sensitivity, lack of need to M. smegmatis and consequent virucidal treatment that are essential in PMS-phage assay for making lawn and inactivation of exogenous mycobacteriophages respectively.

Comparative Characteristics of the Amino Acids Composition of Sheep Milk from Breeds of Northern Kazakhstan

Kazakhstan is characterized by a wide variety of natural, climatic, economic, and ethnic factors that have a specific impact on the development of sheep farming. The production of dairy products from sheep is limited due to the low productivity of animals and the seasonality of milk production throughout the year, as well as the short lactation period. Also, one of the problems is manual milking of sheep, which does not allow obtaining sheep milk on an industrial scale. The market of dairy products, currently in the Republic of Kazakhstan is represented only by-products made from cow's milk, and at the same time, most of them are products made from cow's milk powder, so the development of products made from sheep's milk is an urgent task. In addition, sheep's milk is a national product, and one of the tasks is to revive the traditional products of the Kazakh people. The analysis of literature studies shows that in-depth studies of the chemical composition of sheep's milk have not been conducted in Kazakhstan. The chemical composition data obtained during the Soviet period only give an idea of the primary chemical parameters obtained by generally accepted basic methods and do not provide reliable information about the deep chemical composition of the milk of local ewes. According to the results of studies, the content of the essential amino acid valine in cow's milk (0.21 g/100g) is also lower than in sheep's milk (9.69-3.79 g/100g). Sheep's milk protein is digested in the human body by 99.1%, and cow's milk protein by 91.9%. According to world experts, one of the advantages of Kazakhstan's domestic milk products is its naturalness, a low share of the use of genetically modified organisms, and environmentally friendly pastures, due to which they receive high-quality and safe products. Therefore, the designated research topic and its analysis are appropriate and relevant.

The Use of Olkuska Sheep Milk for the Production of Symbiotic Dairy Ice Cream

The aim of this study was to determine the possibility of using Olkuska sheep milk for the production of ice cream with probiotics and prebiotics. The study examined the effect of the storage and type of bacteria used for the fermentation of ice cream mixes and partial replacement of inulin with apple fiber on the physicochemical properties, viability of probiotic cultures and organoleptic properties of sheep’s milk ice cream stored at −22 °C for 21 days. The addition of apple fiber reduced the pH value of ice cream mixes before fermentation. In ice cream mixes and ice cream with apple fiber, the lactic acid content was higher by 0.1–0.2 g L−1 than in their equivalents with inulin only. These differences persisted during the storage of the ice cream. After fermentation of the ice mixes, the bacterial cell count ranged from 10.62 log cfu g−1 to 12.25 log cfu g−1. The freezing process reduced the population of probiotic bacteria cells in ice cream with inulin from 0.8 log cfu g−1 in ice cream with Lactobacillus acidophilus, 1.0 log cfu g−1 in ice cream with Lacticaseibacillus paracasei and 1.1 log cfu g−1 in ice cream with Lacticaseibacillus casei. Freezing the varieties with apple fiber also resulted in a reduction of viable bacterial cells from 0.8 log cfu g−1 in ice cream with L. paracasei and Lb. acidophilus to 1 log cfu g−1 in ice cream with L. casei, compared to the results after fermentation. The highest percentage overrun was determined in ice cream with L. paracasei and Lb. acidophilus. Ice cream with L. casei was characterized by significantly lower overrun on the 7th and 21st days of storage. Although L. paracasei ice cream had the highest overrun, it did not cause a significant reduction in the probiotic population during storage. After seven days of storage, the first drop differed significantly depending on the type of bacteria used for fermentation of the mixture and the addition of apple fiber. L. casei ice cream had a longer first drop time than L. paracasei and Lb. acidophilus ice cream. Partial replacement of inulin with apple fiber resulted in a significant darkening of the color of ice cream mixes. Depending on the type of bacteria used for fermentation, the addition of apple fiber decreased the value of the L* parameter. Ice cream mixes and ice cream with inulin and apple fiber were characterized by a high proportion of yellow. Partial replacement of inulin with apple fiber reduced the hardness of ice cream compared to inulin-only ice cream. Moreover, the panelists found that ice cream with inulin was characterized by a sweeter taste than ice cream with apple fiber. Moreover, the addition of apple fiber favorably increased the flavor and aroma perception of the mango-passion fruit. Therefore, the milk of Olkuska sheep could be successfully used for the production of symbiotic dairy ice cream.

Correlation between milk composition and selected blood indicators of liver function in ewes during lactation

The objective of this study was to research correlations between milk composition and selected blood indicators of liver function in ewes during lactation. The research was conducted with samples of milk and blood from Travnik Pramenka ewes (n = 99). Samples were collected in the area of western Slavonia in Croatia from lactating sheep grazing on natural pastures. Chemical composition of sheep milk was analysed as well as biochemical parameters in serum. Positive correlation between ALB : TGC, ALB : ALT, GUK : GGT, CHOL : ALT and AST : GGT was determined, while significant negative correlation was determined between GUK : ALB, GUK : TGC, GUK : ALT, ALB : GGT as well as ALT : GGT. Significant positive correlation was determined between blood and milk indicators, like ALB protein (r = 0.243), ALB : DMNF (r = 0.309) and ALB : SCC (r = 0.249), as well as negative correlation between TGC : MY (r = -0.264), ALT : protein (r = -0.258), lactose : TGC (r = -0.274) and ALT : DMNF (r = -0.234). The relations between indicators of milk composition, milk production and ewes blood indicators as well as their mutual connections indicate the justification of using the analysis of liver status indicators. Accordingly, by using these relations metabolic pathways of liver status indicators could be better monitored, which is important for practice regarding prevention of possible feeding errors and prevention of major production losses while maintaining the health of lactating sheep.

Effects of dietary iodine supplement on sheep milk and cheese

The work reported in this paper addresses the iodine nutritional deficiency that still affects a large number of people. For this purpose, we analyzed the possibility to use, as iodine vehicle, a hard typical ewe cheese, called Canestrato d'Abruzzo, derived from milk of ewes fed with an iodine-fortified diet. Both in the milk and the cheese of these animals, the iodine level was higher than that measured in sheep with a normal diet. An increase in the lactoferrin and iron content was evident in the whey derived from milk of the iodine group. Furthermore, in derived cheese, the caseins seemed more efficiently transformed in small peptides making the product more digestible and, for this reason, particularly suitable for feeding the elderly. In conclusion, the dairy products obtained from ewes fed with iodine diet contain more bioactive compounds so that they represent a useful food to prevent iodine and iron deficiency in lamb and humans.