Tradeoff between production and survival under stress: Role of glucose sparing by the mammary gland

• NISSIM SILANIKOVE• Biology of Lactation Laboratory, Institute of Animal Science, A.R.O., the Volcani Center, P.O.

Box. 6, Bet Dagan 50250, Israel

In modern high-producing dairy cows most (70-80%) of glucose synthesized (around 3 kg per day) by

gluconeogenesis in the liver from VFA is diverted to the mammary gland

First: The effect of heat stress is considered

Pair-feeding experiments show that the reduction in milk yield exceed the

reduction in feed intake

Heat stress is associated with increase in insulin sensitivity

Heat stress is associated by diminished uptake of glucose by the mammary gland (by up to 1 kg out of 3 kg) and almost complete stop of NEFA release fro fat (hence their supply to the mammary

gland)

What are the conclusions from the per-feeding experiments under heat stress?

-“The primary difference between a thermal-neutral and a heat-stressed animal in a similar energetic state is the inability of the hyperthermic beast to employ glucose-sparing mechanisms to homeorhetically prioritize product (milk and meat) synthesis”. -In other words, a glucose sparing mechanism is needed to preserve essential body functions and maintaining their homeostasis.-“From an animal agriculture standpoint, these survival strategies reduce productivity and seriously jeopardize farm economics. “-“Defining the biology and mechanisms of how HS threatens animal health and performance is critical in developing approaches to ameliorate current production issues and is a prerequisite for generating future mitigating strategies to improve animal well-being, performance, and agriculture economics.”

What is the physiological basis for the non-feed intake basis for reduction in

milk yield under stress? The role of milk-born negative feed-

back mechanism

Comparing the effects of prevention of cooling (sprinkling) and shade and prevention of shade on milk

yield of high-producing cows in the middle of the summer (THI around 90)

Table 1

Effect of treatments on milk yield and on the diurnal (day vs. night) variations in milk secretion

Treatments Control (C) SD Cooling (D) SD Sun (E) SD

Initial milk yield, Ld-1 47.9 3.1 49.3 3.5 48.1 3.6

Night, Lh-1 1.801 0.2 1.611 0.2 1.401 0.2

Day, Lh-1 1.452 0.3 1.402 0.2 0.652 0.3

Day/Night yield ratio 0.81a 0.09 0.88a 0.1 0.46b 0.07

Total yield, Ld-1 44.1 2.5 40.3 2.5 21.1 3.1

Decrease in milk Yield, % 7.9a 1.5 18.2b 3.6 55.1c 5.5

Values marked by different superscript numbers are significantly different within columns; values marked with different superscript letters are significantly different within rows.

Silanikove et al. BMC Physiology 2009 9:13 doi:10.1186/1472-6793-9-13

able 3

Effect of treatments on plasminogen activator-plasminogen-plasmin system in milk and on the diurnal (day vs. night) variations in their activity.

Treatments Control (C) SD Cooling (D) SD Sun (E) SD

Average

Plasminogen activator (PA), unit ml-1 11.501a 0.11 15.061b 0.11 17.621c 0.21

Plasminoge (PG), unit ml-

1 27.511a 0.90 25.601b 0.82 23.911c 0.70

Plasmin (PL),), unit ml-1 5.111a 0.11 5.041b 0.09 9.121c 0. 21

Plasminogen/plasmin, ratio 5.381a 0.12 5.081b 0.15 2.621c 0.25

Night

Plasminogen activator (PA), unit ml-1 10.802a 0.30 15.202b 0.15 15.422c 0.19

Plasminoge (PG), unit ml-

1 30.432a 0.90 23.582b 1.30 29.112c 1.50

Plasmin (PL), unit ml-1 5.432a 0.09 4.902b 0.10 6.562c 0.11

Plasminogen/plasmin, ratio 5.602a 0.21 4.812b 0.30 4.442c 0.25

Day

Plasminogen activator (PA), unit ml-1 11.853a 0.17 15.803b 0.15 18.723c 0.29

Plasminoge (PG), unit ml-

1 26.053a 0.17 26.613b 0.16 21.312c 0.15

Plasmin (PL),), unit ml-1 4.953a 0.15 5.113b 0.15 10.402c 0.14

Plasminogen/plasmin, ratio 5.263a 0.16 5.213b 0.17 2.052c 0.25

Values marked with different superscript numbers are significantly different within columns; values marked with different superscript letters are significantly different within rows.

Silanikove et al. BMC Physiology 2009 9:13 doi:10.1186/1472-6793-9-13

Anti-Lactogenic hormones

e.g., Cortisol, Estrogen

Lactogenic hormones e.g., GH,

Prolactin

alveoli

PA

PL

PLG

Frequent milking or suckling

Reaction type 1

Reactiontype 2

12

Blood

Lumen

External effects:Milking, suckling, bacterial invasion

Milk stasis or bacterial invasion

Secondly: the effect of inflammatory stress is considered. During acute inflammation, the demand of the immune

system for glucose may increase by up to 1 kg

Bidirectional communication between immunologically competent cells and the brain. Upon release of TNF by macrophages, both humoral and neural signaling initiates brain responses that in turn exert feedback inhibition on macrophage activity.

Glucose fluxes during inflammation. The activated macrophage releases TNF and in so doing allocates glucose preferentially to itself. Glucose enters macrophages and the brain via GLUT-1, whereas it enters muscle cells via GLUT-4. Released TNF enhances GLUT-1 and decreases GLUT-4 transport. TNF, IL-1, and IL-6 released from the macrophage centrally initiate energy-saving sickness behavior.

Production responses to TNFα treatment in early-lactation dairy cows during the experimental period. Yuan et al, PLOS ONE, 2013

Plasma metabolites and hormones, liver triglycerides, and glucose turnover rate in early-lactation dairy cows in response to

TNFα treatment

Effect of LPS on milk yield (L/d) in treated (circles), control-LPS (triangles), and control-control (squares) quarters. The results are presented as mean ± SD. Values marked by

asterisk are significant at P < 0.001 or lower

Effect of LPS on lactose (%) concentration in treated (circles), control-LPS (triangles), and control-control (squares) quarters. Values marked by asterisk are significant at

P < 0.001 or lower.

Influence of LPS on the gene expression of transport proteins and channel proteins required to supply raw materials for milk. Expression levels of SLC1A4 (A), SLC7A1 (B), SLC27A3 (C), AQP3 (D), and GLUT-1 (E) in mammary glands non-treated (0 h) and at 3, 6, and 12 h after LPS injection were quantified by real-time PCR. Data

represent the mean (SD) (n = 6). *, p < 0.05; **, p < 0.005 vs. 0 h .Kobayashi et al. Veterinary Research 2013

Influence of LPS on the expression of genes related with milk component synthesis. Expression levels of UGP2 (A), PGM2 (B), α-lactalbumin (C), FABP3 (D), SREBP-1 (E), CSN1S1

(F), CSN2 (G), CSN3 (H), WAP (I), and lactoferrin (J) in mammary glands non-treated (0 h) and at 3, 6, and 12 h after LPS injection were quantified by real-time PCR. Data represent mean

(SD) (n = 6). *, p < 0.05; **, p < 0.005 vs. 0 h .Kobayashi et al. Veterinary Research 2013

Influence of LPS on STAT3, STAT5, and NFκB

phosphorylation in mammary glands.

Treatment and time2

Lactate(µM)

Malate(µM)

Citrate(mM)

Citrate:(lactate

+ malate)Nitrite

(µM)

Lactate dehydrogenas

e(U/mL)

Lactoferrin(µg/mL)

Albumin(µg/mL)

ANI

 0 d 132   ±22c 294   ±44b 12.1   ±1a 28.4   ±2.6b 263   ±41b 242   ±45c 392   ±52bc 255   ±39d

 1 d 248   ±40b 356   ±41b 11.0   ±1a 18.2   ±2.5c 372   ±31ab 444   ±58b 610   ±49b 425   ±49c

 2 d 287   ±52b 306   ±46b 10.1   ±1a 17.0   ±2.3cb 541   ±99a 544   ±99b 990   ±53a 795   ±51b

 3 d 511   ±28a 864   ±79a 8.0   ±2b 5.8   ±1.3d 663   ±65a 1,699   ±30a 1,215   ±63a 1,110   ±62a

AFI

 0 d 115   ±12c 216   ±32c 13.1   ±1a 39.6   ±3.3a 225   ±23b 84   ±6d 179   ±48d 172   ±39d

 1 d 105   ±8c 297   ±21b 14.2   ±1a 35.3   ±3.3a 245   ±27b 113   ±7d 185   ±38d 174   ±40d

 2 d 147   ±13c 239   ±15b 14.1   ±1a 36.5   ±2.6a 233   ±22b 267   ±6c 187   ±43d 175   ±41d

 3 d 122   ±9c 255   ±69b 14.0   ±1a 37.1   ±2.3a 300   ±31ab 478   ±38b 182   ±49d 174   ±51d

Concentrations (mean ± SE) of lactate, malate, citrate, nitrite, lactoferrin, and albumin and activity of lactate dehydrogenase in milk of cows approaching natural involution (ANI) or forceful involution (AFI) before the induction of involution (milk cessation) and during the first 3 d after the induction of involution

Effect of subclinical mastitis by coagulase negative staphylococci (CNS) and Streptococci( Strep.) and previous clinical infection with Escherichia coli( Esch. coli) on milk yield, milk conductivity and somatic cell count (SCC) on the whole cow level

) 

 a,b,cValues marked by different superscript letters are statistically significant. The significance of

the main (treatment; P [F])effect is indicated on the right column

Effect of subclinical mastitis by coagulase negative staphylococci (CNS) and Streptococci( Strep.) and previous clinical infection with Escherichia coli( Esch. coli) on

somatic cell count (SCC), gross milk composition (fat, protein and lactose), rennet clotting time (RCT), curd firmness (CF) and the concentrations of lactate, malate and

citrate on a gland level

Linear correlations among glucose (Glu), lactose, glucose-6-phospate (Glu-6-p), citrate/lactate+malate (CA/LA+MA), Glu-6-p/Glu, log SCC and CF. All the data

set on the gland level was applied

Effect of intrammary infection with live strain of E. coli that cause

transient acute mastitis

0 4h 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0

200

400

600

800

1000

1200 Lactate

time

micr

omol

ar

0 4h 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0

50010001500200025003000350040004500

Malate

time

micr

omol

ar

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.001.002.003.004.005.006.007.008.009.00

10.00

LDH

time

Unit/

ml

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.00

100.00

200.00

300.00

400.00

500.00

600.00

700.00 Glucose

time

micr

omol

ar

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.00

50.00100.00150.00200.00250.00300.00350.00400.00

Glucose-6-phosphate

time

micr

omol

ar

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.000.200.400.600.801.001.201.401.601.802.00

Glu-6-p/glucose

time

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.00

100.00

200.00

300.00

400.00

500.00

600.00

700.00

Glucose

time

micr

omol

ar

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.002.004.006.008.00

10.0012.0014.00

Citrate

time

mM

0 4h 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.00

5.00

10.00

15.00

20.00

25.00

30.00

Citrate/lact+mal

time

0 4h 8h 14h24h72h 6d 9d 14d21d28d35d0.00

0.50

1.00

1.50

2.00

2.50

Oxaloacetate

time

mM

0 4h 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

Oxaloacetate/lactate

time

0 4h 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.00

1.00

2.00

3.00

4.00

5.00

6.00

Oxaloacetate/malate

time

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0

200

400

600

800

1000

Pyruvate

time

micr

omol

ar

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

Pyruvate/lactate

time

NAD >NADH NAD >NADH

NADH >NAD

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.001.002.003.004.005.006.007.008.009.00

10.00

LDH

time

Unit/

ml

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.00

50.00100.00150.00200.00250.00300.00350.00400.00

Glucose-6-phosphate

time

micr

omol

ar

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

Glu-6-p- dehydrogenase

time

mUn

it/m

l

0 8h 14h 24h 72h 6d 9d 14d 21d 28d 35d0.001.002.003.004.005.006.007.008.009.00

10.00

LDH

time

Unit/

ml

Proposed model of link between metabolic activity of mammary tissue and blood flow rate. Solid arrows represent mass flux and dashed arrows represent effector mechanisms; + and − represent activation and inhibition, respectively. ADO = adenosine, ARA = arachidonic acid, ARG = arginine, INDO = indomethacin, L-NAME = Nω-nitro-L-arginine methyl ester hydrochloride, NO = nitric oxide, PGI2 = prostacyclin, VDC = vasodilatory compounds. Cieslar et al., 2014, JDS

Glut 1

Lactose synthesize

milk

Blocking the pass of pyruvate to the mitochondria and increase in the activities of f cytosolic LDH and MDH explain the increase secretion of lactate and malate into milk. These changes are associated with dramatic reductions

in NADH/NAD and ATP/ADP ratios

Pseudohypoxia refers to increased cytosolic ratio of free NADH to NAD in cells. Research has shown that declining levels of NAD+ in cancer cells and during aging cause pseudohypoxia, and that raising nuclear NAD+ in old mice reverses pseudohypoxia and metabolic dysfunction, thus reversing the aging process

P

P-

P-

P-Malate

Milk

Metabolic reprogramming induced by HIF-1.

Metabolic reprogramming induced by HIF-1α.

ROS

Stress inflammation

P-

Conclusions. The first response to stress is blocking the penetration of pyruvate into the mitochondria and consequently accumulation of pyruvate in the cytosol and conversion of the oxidative/reductive co-factor from high normal NAD/NADH ratio to high of NADH/NAD ratio in the cytosol and mitochondria. High NADH/NAD ratio induce the conversion of the mammary gland epithelial cells metabolism into pseudohypoxic glycolysis (The Warburg effect). The increased formation of lactate and malate restore the oxidative/reductive co-factor into high NAD/NADH ratio and allow the resolution of the stress. The order of events can be revealed by the kinetics changes in the concentration of Glu, Glu-6-p, pyruvate, lactate, malate, citrate and oxaloacetate in milk and respective enzymes, LDH and Glu-6- p dehydrogenase. The changes in the concentration of these metabolites is closely associated with milk production and quality (curdling)

TLR4-dependent inflammatory mediators affect lactation mastitis and milk supply. Perturbed milk flow, maternal stress, genetic predisposition and sleep deprivation can

lead to accumulation of danger-associated molecular patterns (DAMPs) and heightened TLR4 signaling (or equivalent receptors) in the mammary gland, leading to increased

susceptibility to mastitis and increased severity of the disease. Importantly, activation of NFkB could lead to partial mammary gland involution and may be responsible for the

reduced milk supply associated with mastitis

Warburg effect

Heat stress

Sirtuin enzymes are a conserved family of nictotinamide adenine dinucleotide (NAD)-dependent deacetylases and ADP-

ribosyltransferases that regulate lifespan in lower organisms, and mediate responses to fasting and dietary restriction (DR) in

mammals

The Warburg effect is an essential homeostatic response for animal ability to survive under acute stress. Prevention of its development into chronic situations is important for maintaining health and

productivity

Stress Inflammatory response

Warburg effect – glucose sparing for essential functions

Resolution of stress followed by restoration of normal mitochondrial activity (restoration of high NAD/NADH ratio - activation of SIRT 1)

Chronic stress , or damage to the alveoli

Partial restoration of mitochondrial activity; higher proportion of glycolysis than under normal conditions; chronic impairment of production

Acute elevation of pseudohypoxic conditions (high NADH/NAD ratio- high HIF-1)