Influence of lamb rennet paste containing probiotic on proteolysis and rheological properties of pecorino cheese.

Abstract Pecorino cheeses made from heat-treated ewes' milk using traditional lamb rennet paste (RP), lamb rennet paste containing Lactobacillus acidophilus (LA-5; RPL), and lamb rennet paste containing a mix of Bifidobacterium lactis (BB-12) and Bifidobacterium longum (BB-46; RPB) were characterized for proteolytic and rheological features during ripening. Consumer acceptance of cheeses at 60 d of ripening was evaluated. Lactobacillus acidophilus and Bifidobacterium mix displayed counts of 8 log 10 cfu/g and 9 log 10 cfu/g, respectively, in cheese during ripening. The RPB cheese displayed a greater degradation of casein (CN) matrix carried out by the enzymes associated to both Bifidobacterium mix and endogenous lactic acid microflora, resulting in the highest values of non-CN N and water-soluble N and the highest amount of α s -CN degradation products in cheese at 60 d of ripening. The RPL cheese displayed intermediate levels of lactic acid bacteria and of N fractions. The percentage of γ -CN in RP and RPL cheeses at 60 d was 2-fold higher than in the cheese curd of the same groups, whereas the mentioned parameter was 3-fold higher in RPB cheese than in the corresponding fresh curd according to its highest plasmin content. The lower hardness in RPB at the end of ripening could be ascribed to the greater proteolysis observed in cheese harboring the Bifidobacterium mix. Although differences in proteolytic patterns were found among treatments, there were no differences in smell and taste scores

Technical Note: A Simple Salting-Out Method for DNA Extraction from Milk Somatic Cells: Investigation into the Goat CSN1S1 Gene

Abstract In this study, a sensitive, rapid, and toxic solvent-free method to extract DNA from milk somatic cells was implemented for characterization of the goat α S1 -casein gene ( CSN1S1 ). Methods reported for purification of DNA from milk often involve organic extraction, overnight incubation, or use of expensive commercial kits. The present method was implemented for goat milk and is based on a salting-out protocol. The method yielded an amount of DNA suitable for PCR-RFLP without the need for sample enrichment. The PCR-RFLP of DNA extracted from milk produced amplified and digested products of correct size, comparable with those obtained using PCR-RFLP of DNA extracted from blood. Therefore, milk can be used as an alternative source of DNA, making sample collection easier and reducing stressful practices such as capture, handling, and venipuncture in animal management

Changes occurring in immune responsiveness of single- and twin-bearing Comisana ewes during the transition period.

Changes induced by twin and single lambing in the immune response of 16 periparturient Comisana ewes were studied. Cell-mediated immune responses were evaluated by means of skin tests performed from 3 wk before and up to d 35 after parturition. At d 21 and 7 before lambing, the sheep received an intramuscular injection of the antigen keyhole limpet hemocyanin (KLH), to which the animals had not been previously exposed, to determine their humoral immune response. Starting 3 wk before lambing and up to d 35 postlambing, the ewes were sampled to determine the plasma concentrations of anti-KLH antibody (IgG), IL-6, and IL-1 beta. From parturition through d 35 postpartum, individual milk samples were collected for determination of anti-KLH IgG titers and IL-6 and IL-1beta concentrations by means of a capture ELISA. The number of lambs born affected IL-6 concentrations in ewe plasma; IL-6 secretion always was higher in ewes birthing twins than in single-lambing ewes. Apart from the number of lambs born, the concentrations of plasma IL-6 in ewes were higher at lambing than at d 21 antepartum and at d 35 postpartum. An interaction of number of lambs born x time of sampling was observed for plasma antibody titers to KLH. The IgG concentrations were significantly higher in single-bearing ewes than in twin-bearing ewes before parturition and were very similar across groups after parturition. A time effect was found for the cell-mediated immune response and for anti-KLH IgG concentrations in milk, such that at parturition, cellular responses were lowest, and the anti-KLH IgG concentration was highest. A significant correlation was found for IgG titers to KLH in plasma and milk. Results indicate that IL-6 concentrations in blood can be considered a reliable indicator of stress connected to lambing and that the mammary gland is a microenvironment unrelated to blood stream with respect to interleukins expression. In contrast, a relationship was found for the IgG secretions in milk and blood, which suggests that the assessment of humoral immune status may be combined with milking routine in dairy animals

Airspace effects on the yield and quality of ewe milk.

Abstract Three groups of 12 midlactating Comisana ewes were housed in separate rooms of the same building and assigned to treatments of low (LV, 4.1m 3 ), medium (MV, 5.6m 3 ), or high (HV, 7.3m 3 ) airspace/animal. The concentrations of airborne microorganisms in the experimental rooms were measured twice weekly at 0930 and 1630. Ewe milk yield was recorded daily. Individual milk samples were analyzed weekly for milk composition, coagulating properties, somatic cell concentration (SCC), and polymorphonuclear neutrophil leukocyte count (PMNLC), and fortnightly for bacteriological characteristics; samples with more than 10 6 somatic cells/ml were cultured for mastitis-related pathogens. The LV and MV treatments resulted in higher relative humidity and air concentrations of staphylococci than the HV treatment. Greater amounts of air mesophilic bacteria were also found in the LV than in the HV room. Ewes in the HV group gave greater yields of milk than those in the LV and MV groups. LV milk also had a lower casein content than HV milk. Significant interactions of treatment x time were found for milk protein and fat content as well as for clotting time and clot firmness, with LV milk having the poorest composition and deteriorated renneting ability during the last 3 wk of the trial. The HV ewes had lower SCC and PMNLC and psychrotroph counts in their milk than LV and MV ewes and smaller amounts of mesophilic bacteria and fecal coliforms than LV animals. Subclinical mastitis occurred in two ewes of the LV and one of the MV groups, while no cases were recorded in the HV group. Results suggest that airspace is a critical factor in dairy sheep housing and indicate that a volume allocation of less than 7m 3 /animal may adversely affect the performance and health of the lactating ewe

Indigenous enzymes and leukocyte in sheep milk are markers of health status and physiology of the mammary gland

Plasmin, plasminogen and plasminogen activator in ewe bulk milk were not significantly affected by stage of lactation probably as a consequence of the good health of the ewe udders throughout lactation as indicated by SCC which never exceeded 600,000 cells/mL. Elastase content increased significantly during lactation whereas cathepsin showed the highest content in mid lactation. Changes in macrophages and neutrophyls levels in ewe bulk milk during lactation were also investigated. Macrophages minimally contributed to leukocyte cell count in milk and had the highest levels at the beginning of lactation. An opposite trend was recorded for polymorphonuclear leukocytes (PMNL) that increased throughout lactation showing the highest value in late lactation. The increase of PMNL percentage and elastase content in milk, in spite of relatively low SCC, suggests that PMNL and elastase underwent a physiological increase associated to the remodelling of mammary gland in late lactation

Contribution of macrophages to proteolysis and plasmin activity in ewe bulk milk.

A total of 225 bulk sheep milk samples were collected from 5 intensively managed flocks during early, mid, and late lactation to assess the contribution of macrophages to the regulation of the plasmin-plasminogen system. Samples were analyzed for composition, somatic cell counts, milk renneting characteristics, and for plasmin (PL), plasminogen (PG), and plasminogen activators (PA) activities. Isolation of macrophages from milk was performed using a magnetic positive separation and mouse antiovine macrophage antibody; separated cells were lysed by several freeze-thaw cycles, and activity of urokinase PA (u-PA) was determined. Plasmin activity decreased during lactation (42.06 +/- 0.66, early; 31.29 +/- 0.66, mid; 28.19 +/- 0.66 U/mL, late). The reduction in PL activity recorded in the mid and late lactation milk matched the increase in PG:PL ratio. The activity of PA increased throughout lactation; the highest value being recorded in the late lactation milk (260.20 +/- 8.66 U/mL). Counts of isolated and concentrated macrophages were higher in early and mid lactation milk (3.89 +/- 0.08 and 3.98 +/- 0.08 log10 cells/mL, respectively) than in late lactation milk (3.42 +/- 0.08 log10 cells/mL). Stage of lactation did not influence the activity of u-PA detected in isolated macrophages. The activity of u-PA associated with isolated milk macrophages only minimally contributed to total PA activity detected in milk. Proteolytic enzymes, associated with isolated macrophages, act on alpha-casein hydrolysis, as shown by urea-PAGE electrophoresis analysis. Somatic cell counts did not exceed 600,000 cells/mL, and this threshold can be considered a good index of health status of the flock and of the ability of milk to being processed. Our results lend support to the hypothesis that macrophages in ewe bulk milk from healthy flocks only slightly contribute to the activation of the PL-PG system

Advanced Technologies in Sheep Extensive Farming on a Climate Change Context

Climate change represents a serious issue that negatively impacts the animals’ performance. Sheep production from Mediterranean region is mainly characterized by extensive farming system that during summer are exposed to high temperature. The explored new technologies to monitoring animal welfare and environment could mitigate the impact of climate change supporting the sustainability of animal production and ensuring food security. The present chapter will summarize the more recent advanced technologies based on passive sensors, wearable sensors, and the combination of different technologies with the latest machine learning protocol tested for sheep farming aimed at monitoring animal welfare. A focus on the precision technologies solution to detect heat stress will be presented

Relationship between cortisol response to stress and behavior, immune profile, and production performance of dairy ewes.

The existence of a relationship between cortisol levels, after an acute stress, and behavioral activities, immunological profile, and production performance in sheep was studied. An initial flock of 30 Comisana ewes was involved in the experiment, and each of the 30 ewes was individually subjected to an isolation test in a novel environment. Subsequently, from the initial flock, 2 groups of 8 Comisana ewes were each retrospectively selected, and the animals were divided, according to their cortisol concentration 10 min after the isolation test, into high cortisol (HC) ewes, having a peak of cortisol concentration >90 ng/mL (average: 119.3 ng/mL +/- 11.8), and low cortisol (LC) ewes having a peak of cortisol concentration <80 ng/mL (average: 52.4+/-11.8). During the isolation test, the behavior of each animal was video-recorded and behavioral activities were registered. Blood samples were collected before the isolation test, immediately after the test (10 min), and at 60, 120, 300 min, 24 h, and 48 h after the test to evaluate percentages of T-helper (CD4(+)) and T-cytotoxic (CD8(+)) cells, CD4(+)/CD8(+) ratio, and IL-1beta and IL-6 levels. The ewes were milked for 3 d after the isolation test to determine cortisol levels and IL-1beta and IL-6 concentrations in whey. Milk yield was recorded at each milking, and milk samples were analyzed for pH, nutritional parameters, renneting properties, and somatic cell count. During the isolation test, HC ewes exhibited a shorter duration of movement and fewer bleats than LC ewes. The average plasma IL-1beta concentration was higher in HC than in LC ewes. The average whey IL-1beta and IL-6 concentrations were higher in whey from HC ewes than in LC ewes. A positive correlation emerged between plasma and whey IL-1beta concentrations. The average CD4(+)/CD8(+) ratio in blood was lower in HC than in LC ewes. Time from isolation affected the CD4(+)/CD8(+) ratio: at 120 min, the CD4(+)/CD8(+) ratio increased compared with that at 10 min after isolation and then decreased until 300 min after isolation. On average, ewes with low cortisol concentrations showed higher milk production and lower SCC than ewes with high cortisol concentrations. Results suggest that plasma cortisol concentration is connected to the behavioral response and immune competence of dairy ewes and cytokine concentrations. Both whey IL-1beta and IL-6 can be considered reliable indicators of the magnitude of hypothalamic-pituitary-adrenal axis activation. The stress-induced changes in CD4(+)/CD8(+) ratio are critical for controlling disease incidence and planning appropriate vaccination programs. High reactivity of the hypothalamic-pituitary-adrenal axis is also associated with a reduction in milk production and an increased predisposition to develop intramammary inflammatory processes

Effects of Somatic Cell Count and Stage of Lactation on the Plasmin Activity and Cheese-Making Properties of Ewe Milk

The experiment was conducted from March to July 2002 using 5 intensively managed flocks of Southern Italy. In each flock, 2 groups of 50 ewes were created. The groups were designated LSCC (low somatic cell count [SCC]) when their milk SCC was lower than 500,000/mL and HSCC (high SCC) when their milk SCC was higher than 1,000,000/mL. Bulk milk and whey samples were analyzed for fat, total protein, lactose, casein, and whey protein contents. Renneting properties of milk were also determined. Moisture, NaCl, and nitrogen fractions were determined in fresh cheese curds. In addition, plasmin (PL) and plasminogen (PG) activities in milk and cheese were monitored. The proteolytic activity of plasmin by urea-polyacrylamide gel electrophoresis and the white blood cell (WBC) differentials were determined. The HSCC resulted in higher pH values in milk and in higher moisture and lower fat contents in fresh cheese curds. Moreover, a lower recovery of fat and whey proteins was obtained from the HSCC than from the LSCC raw milk. The crude protein and casein contents were higher in the HSCC than in the LSCC curds during early and midlactation; an opposite trend was observed in late lactation. Plasmin and PG activities underwent more marked fluctuations in the LSCC than in the HSCC curds through lactation. The results of this experiment demonstrate that the PL activity in ewe milk is markedly influenced by the SCC, although SCC is not the only parameter for predicting PL and PG evolution in ewe milk. The LSCC milk resulted in a higher proteolytic potential of Canestrato pugliese cheese curds

Effect of solar radiation and flaxseed supplementation on milk production and fatty acid profile of lactating ewes under high ambient temperature

Abstract The objectives of this study were to evaluate the effects of protection from solar radiation and whole flaxseed supplementation on milk yield and milk fatty acid profile in lactating ewes exposed to high ambient temperature. The experiment was conducted during summer and involved 40 ewes divided into 4 groups. The ewes were either exposed (not offered shade) or protected from solar radiation (offered shade). For each solar radiation treatment, ewes were supplemented with whole flaxseed or not. Milk samples from each ewe were collected at the morning and afternoon milking every week, and analyzed for pH, total protein, casein, fat, and lactose content, somatic cell count, and renneting parameters (clotting time, rate of clot formation, and clot firmness after 30min). At the beginning of the experiment, and then at d 23 and 44, milk samples were analyzed for milk fatty acids using gas chromatography. Flaxseed supplementation significantly increased milk yield, fat, protein, and casein yields, and somatic cell count, and increased fat and lactose contents of milk. A decrease of saturated fatty acids from C6:0 to C16:0 and an increase of C18:1 trans -11 and C18:2 cis- 9, trans -11 was observed in milk from flaxseed-supplemented ewes. Flaxseed supplementation decreased saturated fatty acids content and increased total monounsaturated fatty acids content, the total content of isomers of conjugated linoleic acid, and polyunsaturated fatty acids content in milk. Flaxseed also increased the α-linolenic acid content of milk. As a result, milk from supplemented groups showed an increase in n-3 fatty acid content. Flaxseed supplementation decreased short-chain and medium-chain fatty acids, and increased long-chain fatty acid content of milk. On average, flaxseed supplementation increased the C18:2 cis -9, trans -11/C18:1 trans -11 Δ 9 -desaturase index starting from d 23 of the experiment, in correspondence with the highest C18:2 cis -9, trans -11 content of milk from flaxseed-supplemented ewes. Flaxseed decreased atherogenic and thrombogenic indices of milk. Protection from solar radiation during summer did not improve yield and composition of ewe milk. Nevertheless, milk from ewes exposed to solar radiation showed decreased long-chain fatty acid and polyunsaturated fatty acids contents, and in particular, decreased vaccenic acid, rumenic acid, and total conjugated linoleic acid contents