Proteolysis in Milk During Experimental Escherichia coli Mastitis

Moussaoui, F.; Vangroenweghe, Frédéric; Haddadi, Kahina; Roux, Yves Le; Laurent, François; Duchateau, Luc; Burvenich, Christian

doi:10.3168/jds.s0022-0302(04)73423-2

Cited by 34 publications

(50 citation statements)

References 42 publications

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“…dysgalactiae-infected glands shed these microorganisms, whereas E. coli-infected glands were several weeks post proved infection. The resulting effects of the latter bacteria are in agreement with other reports (Le Roux et al, 2003;Moussaoui et al, 2004). Moreover, the results also indicate that impact of bacterial infection within species is inconsistent.…”

Section: Resultssupporting

confidence: 82%

Real-time visual/near-infrared analysis of milk-clotting parameters for industrial applications

Leitner

Merin

Lemberskiy-Kuzin³

et al. 2012

Animal

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The economical profitability of the dairy industry is based on the quality of the bulk milk collected in the farms, therefore it was based on the herd level rather than on the individual animals at real time. Udder infection and stage of lactation are directly related to the quality of milk produced on the herd level. However, improvement of milk quality requires testing each animal's milk separately and continuously. Recently, it was postulated that online equipment can estimate milk quality according to its clotting parameters, and thus result in better economical return for cheese making. This study further investigated the potential application of the AfiLab TM equipment to provide real-time analysis of milk-clotting parameters for cheese manufacture and cheese yield on quarter (1018) and individual cow (277) levels. Days in milk, lactose, log SCC and udder infection were found to have a significant effect on curd firmness and cheese properties and yield. The results clearly indicate that: (a) the parameter Afi-CF determined with the AfiLab TM is suitable for assessing milk quality for its clotting parameters, a value which is not provided by merely measuring fat and protein content on the gland and the cow levels; (b) bacterial type is the single major cause of reduced milk quality, with variations depending on the bacterial species; and (c) early and late lactation also had negative effects on milk-clotting parameters. Cheese made from the various milk samples that were determined by the Afilab TM to be of higher quality for cheese making resulted in higher yield and better texture, which were related mainly to the bacterial species and stage of lactation.

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Section: Resultssupporting

confidence: 82%

Real-time visual/near-infrared analysis of milk-clotting parameters for industrial applications

Leitner

Merin

Lemberskiy-Kuzin³

et al. 2012

Animal

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“…Elevated SCC and mastitis may increase TJ permeability (Moussaoui et al, 2004), but this did not seem to be the case in Cluster 1, as the mean value of SCC was low (,100 000 cell/ml), indicating that feeding level was probably the main factor responsible for the findings.…”

Section: Resultsmentioning

confidence: 88%

Severe feed restriction increases permeability of mammary gland cell tight junctions and reduces ethanol stability of milk

Stumpf

Fischer

McManus

et al. 2013

Animal

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A total of twelve lactating Jersey cows were used in a 5-week experiment to determine the effects of severe feed restriction on the permeability of mammary gland cell tight junctions (TJs) and its effects on milk stability to the alcohol test. During the first 2 weeks, cows were managed and fed together and received the same diet according to their nutritional requirements (full diet: 15 kg of sugar cane silage; 5.8 kg of alfalfa hay; 0.16 kg of mineral salt and 6.2 kg of concentrate). In the 3rd week, animals were distributed into two groups of six cows each. One group received the full diet and the other a restricted diet (50% of the full diet). In the 4th and 5th weeks, all animals received the full diet again. Milk composition and other attributes, such as titratable acidity, ethanol stability, pH, density and somatic cell count (SCC) were evaluated. Cortisol levels indicated the stress condition of the cows. Plasma lactose and milk sodium were measured to assess mammary TJ leakiness. Principal factor analysis (PFA) showed that the first two principal factors (PFs) contributed with 44.47% and 20.57% of the total variance in the experiment and, as feeding levels increased, milk stability to the ethanol test became higher and plasma lactose levels decreased, which indicates lower permeability of the mammary gland cell TJ. Correspondence analyses were consistent with PFA and also showed that lower feeding levels were related to reduced milk stability, high plasma lactose, high sodium in milk, low milk lactose (another parameter used to assess TJ permeability) and higher cortisol levels, indicating the stress to which animals were submitted. All observations were grouped in three clusters, with some of the above-mentioned patterns. Feeding restriction was associated with higher permeability of TJ, decreasing milk stability to the ethanol test.

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“…Mehrzad et al [27] reports that milk PMN viability plays a critical role in the pathogenesis and outcome of coliform mastitis. The value of the bacterial count in milk did not exceed 10 5 cfu·mL -1 for some authors [17,23], whereas it exceeded 10 7 cfu·mL -1 in previous studies by Riollet et al [28]. Bacterial growth in milk in vitro is different from growth in the udder quarter of a cow.…”

Section: E Coli Growth In Raw Milk and Gelatinase Activitymentioning

confidence: 87%

“…Plasmin activity was measured by a method based on the release of a yellow compound (measured at 405 nm) when a synthetic substrate (D-Val-Leu-Lys p-nitroanilide dihydrochloride; Sigma) for plasmin was hydrolysed, after addition of a dissolving reagent [17].…”

Section: Plasmin Activitymentioning

confidence: 99%

E. coliproteolytic activity in milk and casein breakdown

Haddadi¹,

Moussaoui²,

Hebia³

et al. 2005

Reprod. Nutr. Dev.

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-Previous studies have focused on both LPS and E. coli experimental mastitis and underlined the respective roles of endogenous proteolysis (including plasmin from the blood stream and other proteases from milk leukocytes), as well as the presence of E. coli in a more intricate system. The aim of this study was to assess the role of E. coli in milk proteolysis and especially that of its proteases in casein breakdown. The first part consisted in the incubation of 10 4 cfu·mL -1 of the E. coli strain in raw milk at 37 °C for 24 h; the same milk was also incubated with 0.04% sodium azide. Several parameters were evaluated: CFU, plasmin activity, gelatinase activity and pH 4.6 insoluble peptides, including the proportion of γ-CN. The profile of gelatinase activity was determined by zymography and identified by immunoblotting. In the second part of the study, we examined the profile of CN (αs-, β-and κ-CN) breakdown by E. coli lysate. The results suggest that E. coli proteases have a direct effect on CN, and the increase of γ-CN in inoculated milk may be generated by both plasmin and the gelatinase. Moreover, the gelatinase activity in the inoculated milk was higher after 24 h of incubation.caseins / γ-CN / E. coli / gelatinase activity / milk / plasmin Abbreviations: CFU: colony-forming units; CN: casein; IMI: intra-mammary infusion; PA: plasmin activity; PI: post inoculation; SCC: somatic cell count.

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Proteolysis in Milk During Experimental Escherichia coli Mastitis

Cited by 34 publications

References 42 publications

Real-time visual/near-infrared analysis of milk-clotting parameters for industrial applications

Real-time visual/near-infrared analysis of milk-clotting parameters for industrial applications

Severe feed restriction increases permeability of mammary gland cell tight junctions and reduces ethanol stability of milk

E. coliproteolytic activity in milk and casein breakdown

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