Disruption of cell junctions induces apoptosis and reduces synthetic activity in lactating goat mammary gland

Chedly, Hedi Ben; Boutinaud, Marion; Bernier-Dodier, P.; Marnet, Pierre‐Guy; Lacasse, P.

doi:10.3168/jds.2009-2678

Cited by 33 publications

(19 citation statements)

References 37 publications

(47 reference statements)

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“…hypothesized that the switch of tight junctions to a leaky state during the first 24 h of ODM may be part of the acute regulatory mechanism decreasing milk yield. This assumption is consistent with data from oligonucleotide-array study (Littlejohn et al, 2010) or from studies using calcium chelators to mimic the effect on mammary epithelium integrity (Stelwagen et al, 1995;Ben Chedly et al, 2010). These studies reported decreased synthetic activity and the induction of cell death.…”

Section: Plasma Lactose Concentrations Are Poorly Correlated With Milsupporting

confidence: 87%

Lactose in blood plasma and the ability of dairy cows to tolerate once-daily milking in terms of milk loss and milk recovery

Guinard-Flament

Gallard

Larroque

2011

Journal of Dairy Science

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This experiment described the variability among cows with the aim of studying the ability of dairy cows to tolerate once-daily milking (ODM) in terms of milk losses and milk recoveries observed when cows are switched from twice- to once-daily milking and then back to twice-daily milking (TDM). It also aimed to investigate whether or not lactose in blood plasma, which indicates the mammary epithelium permeability, is correlated with milk losses and recoveries and, consequently, a potential candidate assessor of dairy cow tolerance to ODM. The study used 86 crossbred dairy cows (Holstein × Normande) split into 5 groups over 2 yr. The trial consisted of 3 successive periods: a 1-wk control period of TDM, then 3 wk of ODM, followed by 2 wk of TDM. Blood samples were collected 1 to 1.5h before the morning milking and 5 to 6h after milking on d -3, 0, 1, 3, 7, 21, 23, and 28, where d 0 is the last d of the control period. Milk losses measured as kilograms per day were higher in cows with highest control-period milk yields (r=-0.66). When expressed in relative terms (%), milk losses were weakly correlated with the control-period milk yield (r=-0.22). When switched back to TDM, cows recovered only 47% of the milk lost. Milk recovery (kg/d) was weakly correlated with control milk yield (r=0.34) and not correlated with ODM milk yield. Milk recovery was correlated with milk yield losses: the higher the milk yield losses (kg/d or %), the higher the milk recovery (kg/d; r=-0.59 and -0.52, respectively). Rate of milk recovery expressed as the quantity of milk recovered per kilogram of milk lost, was not correlated with milk loss expressed as a percentage. This means that to be considered well-adapted to ODM scheduling, a cow must be well adapted to milk loss, and be well adapted to milk recovery. Blood plasma lactose concentration (log(10)-transformed data) was not correlated with milk production levels in either control, ODM, or back-to-TDM periods. It was poorly correlated with milk loss but was positively correlated with milk recovery (kg/d) and rate of milk recovery. We conclude that blood plasma lactose needs to be coupled with other indicators for evaluating dairy cow tolerance to ODM.

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Section: Plasma Lactose Concentrations Are Poorly Correlated With Milsupporting

confidence: 87%

Lactose in blood plasma and the ability of dairy cows to tolerate once-daily milking in terms of milk loss and milk recovery

Guinard-Flament

Gallard

Larroque

2011

Journal of Dairy Science

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“…However, our finding revealed that the disruption of tight junctions occurs only on the first day of ODM application and disappears thereafter. The disruption of mammary epithelium has been associated with a decrease in the expression of constitutive tight and adherens junctions protein such as occludin and E-cadherin respectively (Ben Chedly et al, 2010). The similar labelling intensity of E-cadherin observed for the ODM/TDM and control groups after 2 days of the ODM period suggests that adherens junctions was not affected by ODM after 2 days of treatment.…”

Section: Discussionmentioning

confidence: 90%

The decrease in milk yield during once daily milking is due to regulation of synthetic activity rather than apoptosis of mammary epithelial cells in goats

Chedly

Lacasse

Marnet

et al. 2013

Animal

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Once daily milking (ODM) is a management practice that can improve working conditions and reduce production costs in dairy farming compared with twice daily milking (TDM). However, ODM is associated with a decrease in milk yield. Previous research indicated that disruption of tight junctions in the mammary gland may be one of the regulatory factors involved in the milk yield decrease observed during ODM. The aim of this study was to investigate the involvement of mammary epithelium disruption in the regulation of the activity and dynamics of mammary epithelial cells (MEC) during 5 weeks of ODM in goats. Twelve alpine goats (producing 3.67 ± 0.64 kg/day and 47 ± 1.6 days in milk) were assigned to two groups that were milked once or twice a day during 5 weeks and then switched back to TDM. Mammary biopsies were collected before and on days 2 and 16 of both ODM and TDM switchback periods. Milk purified epithelial cells were collected before and on days 1, 7, 21 and 28 during ODM as well on days 1 and 7 of the TDM switchback period. The mRNA levels of genes involved in the regulation of synthetic activity and apoptosis were analysed by RT-PCR in milk MEC and mammary biopsies. ODM decreased yields of milk (−23%), lactose (−23%) and casein (−16%). Lactose synthesis was regulated at the transcriptional level by downregulation of α-lactalbumin mRNA levels in both biopsy samples (−30%) and milk MEC (−74%). TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling) staining of mammary gland biopsies did not show any increase in cell apoptosis after 2 and 16 days of ODM (0.8% and 1%, respectively) despite upregulation of Bax mRNA levels in milk MEC. This suggests that the decrease in milk yield observed during ODM is attributable to a decrease in synthetic activity rather than to induction of MEC cell death. ODM induced the disruption of tight junctions in the mammary gland only on the first day of the treatment as indicated by increased blood lactose concentration. This indicates that the decrease in MEC activity observed over the 5 weeks of ODM was not due to disruption of the mammary gland tight junctions. There was no carryover effect of 5 weeks of ODM on milk production. Therefore, it appears that the decrease in milk yield that occurs during ODM in goats is due to regulation of synthetic activity rather than to apoptosis of MEC.

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“…ECM) was sufficient to induce expression of casein genes without the addition of any growth factor, highlighting the essential role of integrins [123,134]. Interestingly, in goat mammary tissue in vivo and in vitro disruption of cell junctions strongly reduced milk yield and expression of casein and alpha-lactalbumin [135].…”

Section: Regulation Of Milk Protein Expressionmentioning

confidence: 99%

Milk Protein Synthesis in the Lactating Mammary Gland: Insights from Transcriptomics Analyses

Bionaz¹,

Hurley²,

Loor³

2012

Milk Protein

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Disruption of cell junctions induces apoptosis and reduces synthetic activity in lactating goat mammary gland

Cited by 33 publications

References 37 publications

Lactose in blood plasma and the ability of dairy cows to tolerate once-daily milking in terms of milk loss and milk recovery

Lactose in blood plasma and the ability of dairy cows to tolerate once-daily milking in terms of milk loss and milk recovery

The decrease in milk yield during once daily milking is due to regulation of synthetic activity rather than apoptosis of mammary epithelial cells in goats

Milk Protein Synthesis in the Lactating Mammary Gland: Insights from Transcriptomics Analyses

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