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Application of Biologically Relevant Lighting
in Animal Husbandry
Paul West BSc.
Tropical Marine Centre Ltd.
BPEX Innovation 2015
The Evolution of Sight
We all made our evolutionary start
in the same watery environment
The Importance of Blue
The progressive absorption of longer wavelengths with depth gives
the ocean its blue colour and its evolutionary significance, and the
sky gives similar spectral cues on land as it does underwater
In the last two decades science has shown that blue wavelengths
have the power to reset the biological clocks in all vertebrates, with
greater efficiency than any other wavelength.
Biological effect of light
Melatonin is the almost universal molecule used to record day
length without which we might all have remained benthic
dwellers!
In vertebrates, melatonin is produced in darkness, usually at night, by
the pineal gland in response to light received by the eye or, in the case
of chickens, directly by receptors in the brain.
Biological function via the
pineal is 20 x more
sensitive to light than
colour vision via cone cells
It is principally blue light, around 460 to 480 nm, that
suppresses melatonin, most importantly proportional
to the light intensity and length of exposure.
The Evolutionary ‘bottleneck’ in development of vision
An evolutionary ‘bottleneck’ is
postulated when dinosaurs ruled the
earth.
Early mammals were forced into a
nocturnal mode of life and lost the
ability for full colour vision,
Birds and most fishes escaped this
pressure and remained largely daytime
feeders with the full range of retinal
pigments seen in modern species
After the disappearance of dinosaurs most mammals reverted to a
diurnal daytime living pattern and re- acquired dichromic colour
vision but only Primates and some squirrels developed full colour
trichromic vision
Spectral sensitivity of modern vertebrates
380nm
320-415nm
425nm
520nm
460nm
560nm
430nm
540nm
439nm
556nm
445nm
552nm
428nm
635nm
580nm
600nm
539nm
Note that many fish and most birds retain visual
sensitivity to invisible Ultra-violet (UV) light
Vision is a matter of lifestyle - Pig v. Fish
Pig
Foraging omnivore
Crepuscular behaviour
Seasonal breeder
Short day responsive
Dichromatic colour vision
No adaptation to detect UV light
No extra- retinal light sensors
Pig’s retina- 2 cone types
556 nm (Green - M type)
439 nm (Blue - S type)
Salmon
Predatory Carnivore
Diurnal behaviour
Seasonal breeder - Migratory
Long day responsive
Trichromatic colour vision
Can detect UV and polarising light
Skin (melanophores) and pineal?
Salmon’s retina - 4 cone types
635 nm (Red - L type),
520 nm (Green – M type)
425 nm (Blue – S type),
380 nm (UV- S type)
Evolution Of Light
The incandescent light bulb widely used in the twentieth
century was very inefficient, producing lots of heat and
relatively little biologically relevant BLUE light.
The introduction of fluorescents improved energy efficiencies of
lighting considerably and became popular particularly in
commercial applications such as animal production.
Then in 1990’s came the birth of the BLUE LED and white
LEDs have since come into wide use in the last 5 years
LED’s will revolutionised animal lighting
LED’s are super -efficient and digitally
controllable. They are dimmable and able to
produce a spectral output to meet all
requirements
300 lm/W
70 lm/W
16 lm/W
0.1 lm/W
But LED’s high content of BLUE light also make them very powerful
at mediating our biological (circadian ) rhythms via the pineal
Comparison of Lighting Technology
28w AgriRay Natural Daylight
LED
Useable Life
Hazardous Chemicals
Heat Output
Flicker Frequency
Operating temp.
Dimmable / Digital
Bulb Changes
Directional Light
On/Off cycling
58w Fluorescent Natural Daylight
Fluorescent
50,000 hrs
8000 hrs (recommended)
No
Yes - Mercury
Low
High
1000 Hz
120 Hz (magnetic)
-40o to 40o C
-0o to 40o C
Yes
Not easily
Lifetime -10 years
Yes 24 months
20 -120o (lensing available)
180o (requires reflector)
No Impact
Shortens Lifespan
What colour is light ?
Trichomat – Human
The way a human (three cones)
would see a scene
Dichromat – Pig’s view
The way a pig (two cone) might see
the same scene
How bright is right?
Brightness will depend on how much energy is
emitted in the range of the visual cone pigments.
Two basic types of visual photoreceptive cells in the retina
Rods and Cones
Rods - Detect light and dark changes
only. Slow adapting. Low acuity but very
sensitive in peripheral vision. Essential
for nocturnal and crepuscular animals
which feed under low light levels
Cones - Sensitive to colour. Fast
adapting. High acuity for detailed
focused vision. Essential for diurnal
animals which feed during the day
under normal / bright light conditions
Pigs may perceive low lux levels of incandescent, high pressure
sodium (HPS) lamps and even aging fluorescents as dim
because they produce less of the blue and green wavelengths
pigs are sensitive to. Under reduced light pigs may be using
rods and cones so these types of light are likely to reduce the
the visual acuity of the pig under these conditions
Biologically relevant lighting for Pigs
439 nm
556 nm
439 nm
556 nm
439 nm
556 nm
Maximum Melatonin
Suppression
= Biological Clock and
Season breeding
Lower Melatonin
Suppression
= Effects on
Biological Clock and
Season breeding ??
LED’s produce more photon rich SHORT wave light where animals need
it, both visually and biologically, having a more powerful effect in
mediating Melatonin secretion and control of the biological clock
Output pathways for retinal vision and biological function
Vision via
Rods and Cones
Retinal
vision
Visual Stimuli
Visual Reflexes
Biological Function via
Pineal
Acute
Effects
Melatonin Secretion
Body temperature
Cortisol Secretion
Heart rate
Alertness
Cognitive performance
Psychomotor performance
Brain blood flow
EEG responses
Clock gene expression
Long-term
effects
Circadian
regulation
Sexual maturity
Reproductive
success
Growth rate
Muscle and Bone
development
Immunity
Typical circadian rhythm of melatonin, cortisol and GH
Appropriate BLUE spectrum lighting in the range of 460 – 485 nm is needed
to entrain biological function and drive a predictable response
Effect of spectral quality on animal production parameters is best
illustrated by extensive studies in poultry farming
Reduced injurious Feather
Pecking (Lewis et al., 2000b)
(Harrison et al., 1969)
Pigs
Improved mating attemps
(Jones et 2001)
Minimises fear (DEFRA 2007)
Calmer flock
Meat
Broilers
Layers
Reduced flapping / noise in
shackling area (Adamczuk et al
2014)
Reduces PSE, Better meat
quality. (Claudia F. Barbosa
2013)
Improves meat quality by
raising antioxidative capacity
Y. Ke et al 2011)
?
Improved Growth
(I Rozenboim et ., 1998)
Stronger Egg Shells
( Er et al., 2007)
Healthier Immune system
Better skin & bone quality
(Sharif et al., 2011)
(D.S. Prayitno et al., 1995)
Stimulates muscle growth
(Zhang et al., 2013)
Improves Egg production
(El Halwani 2007)
Improve bird mobility
Stimulate reproduction
(El Halwani 2007)
(Rakibul Hassan 2013)
?
Applications of biologically relevant lighting
Production
Stage
Broodstock
Egg
production
Hatchery
Grow-out
Application for
Lighting
Control of breeding seasons
Conditioning of broodstock
Delaying maturation
Long distance transport
Synchronise hatching
Egg quality assessment
Control of incubation
Livefood production
Improving first feeding
Juvenile transport/ acclimation
Extending feeding hours
Controlling behaviour
Improving growth & mobility
Spatial distribution
Harvest /
Slaughter
Improving output
Reducing stress at harvest
Transport to abattoir
Reducing stress in lairage
Disease
Control
Inspection of stock
Control of Parasites
Control of Bacteria
Improving Vaccination
Aquaculture Agriculture
Species appropriate units for quantifying the
visual impact and biological effects of a given
light source are still lacking. We must define a
‘biologically’ rated and more relevant measure
of light for each animal we are working with a biolumen sps
Future Potential of Improved Lighting in Pig Production
Dr. Nina Taylor (2010) produced an excellent review of the status of knowledge about the
effect of lighting on Pigs and I expand on her summary here:
Seasonality and productivity – wide range of contradictory information.
Effect of varying day-length well documented but experiments not fully
defined in respect of other relevant lighting parameters ie: spectral quality
and pig relevant visible illuminance.
Potential to improve reproductive success, seasonal infertility and general
productivity by full control of lighting eg; improved spectrum,
reinforcement of circadian rhythms and dawn/dusk phasing
Welfare – Inappropriate lighting (continuous lighting) is recognised to impact
welfare. Commercial lighting may be adequate but not optimised for spectrum
and pig relevant illuminance.
Improved control of dawn /dusk and overall reinforcement of melatonin
mediated circadian rhythms to reduce stress and optimise production
through improved lighting conditions can deliver welfare benefits.
Legislation for farmed pigs, as it relates to lighting has little basis in
science. EU and UK regulation makes no recommendation in respect
of spectral quality, pig relevant illuminance levels, nor considers
potential benefits of reinforcement of important circadian driven
functions which are now known to be important in human health.
Improving lighting conditions including the colour of enclosures
to maximise the visual acuity of the pig may improve
environmental enrichment, conspecific recognition, and the
resultant social behaviour and interactions ie: reduce tail-biting
Meat quality – There is almost no work done on the impact of
controlling spectrum and illuminance during pre-slaughter conditioning,
transport, lairage and in the stunning chute, on incidence of PSE and
DFD in pigs .
Work in poultry suggests control of spectral quality in preconditioning and calming livestock in transport and lairage is
worth closer investigation and could deliver significant
commercial rewards.
Visual Light in Managing Bio-Security in the Supply Chain
The use of invisible but harmful Ultra-violet UVc wavelengths is well documented
for controlling pathogens but increasingly an application is emerging for high
intensity but safer visible blue light.
•
Control of many bacteria and yeast on surfaces and liquid films using visible
405 nm blue light has been demonstrated including 2 log reductions in
Escherichia, Salmonella, Shigela, Listeria, Mycobacterium
Campylobacter.(Murdoch L.E et al 2012, Endarko E et al 2012, Murdoch L.E
et al 2010) and Saccharomyces cerevisiae, Candida albicans and Aspergillus
niger (Murdoch L.E et al 2013). This may have application in controlling
pathogens in animal holding and processing facilities – even water
supplies and open drinking troughs
•
Several workers have demonstrated the lethal effect of visible blue light
including 417 nm wavelength on a wide range of higher insect pests including
beetles, mites and all stages of Drosophila melanogaster. (Masatoshi Hori et
al 2014) There is certainly potential for control of parasites in animal
enclosures
Thank you for listening
and special thanks to
Charlotte West of BPEX for inviting me to
give this presentation
‘Nothing in biology makes sense except in the light of evolution’
Theodosius Dobzhansky 1973
Soviet-born geneticist and evolutionary biologist
‘Almost everything in biology makes sense with the evolution of light’
Paul West 2015