Lecture 10b: Nutrition Science Flashcards
What does nutrition science include
- diet production
- clinical case
- nutritional welfare
- research
Two types of nutrition science research
- conservation based
- well-being based
Vancouver Island Marmots
- endemic to Vancouver
- major population changes since the 70s
- not a self-sustaining population
- On the brink of extinction
Challenges of survival for the Marmots
- forestry: intensive logging practices
- predators: altered landscape increase access to predators
- late maturing: 3-4 years old
- frequency of reproduction: reproduce every other year to 3-4 pups
Survival of marmots
- low yearly survival rate
- captive bred and released marmots. have a higher risk of mortality
- issues relate to the first hibernation
Gaps in our knowledge about marmots
- body composition
- wild type diet (1 publication)
- captive diet (does it match)
Hibernation physiology and diet fatty acid
- hibernators drop core body temperature, they have the physiology to do that
- mortality of non-hibernators is from heart failure which is caused by increased cytosolic CA2+
- hibernators maintain Ca2+ influx and release through SERCA proteins
- these proteins are influenced by the presence and ratio of PUFA in the sarcoplasmic reticulum
What is their hypothesis for marmots in captivity?
Lipid metabolism and hibernation of Vancouver Island Marmots are affected by captivity
VIM in captivity
- increased body condition
- cardiovascular disease
- shortened hibernation
- first wild hibernation survival
- hibernation and breeding success
Fatty Acid Profiles
- looked at their fatty acid profiles
- what does their fat and blood look like in the context of fatty acids since fatty acids impact their ability to hibernate
Fatty acid profiles of VIM in captivity
- had higher fatty acids in their blood
- high ratio of N6:N3
- increased short fatty acid chains
- elevated palmitoleic acid and cis-vaccenic acid
Fatty acid profiles of VIM in the wild
- had long fatty acid chains
- high HUFA score = good CV health
Data for developing research pellet
- coalescing data from comparative species (plant preferences, stomach contents, WAT & organs)
- hibernation studies
- season changes in FA profiles
Research pellet
n6:n3 ratio ~ 1.0
old one was 5.0, 5 n6 for every 1 n3
Diet study for the VIM
- used woodchucks
- treatment group: start on high n3 diet and then swithc to high n6 late in summer
- control group: high n6 diet entire study
- determine if we could alter their hibernation and could we alter their health outcomes
woodchuck results from the diet study
- assessed: diet intake, body weight, body composition, body temperature, fatty acid profiles
- failed hibernation
- but, more favourable FA profile
- one the road to improve their health, maybe not hibernation yet
Conservation impacts on VIM
- improve diet in captivity
- captive vs wild (continue to study - missed?)
- fatty acid “targets”
- more resilient captive populations
when are polar bears the fattest?
may/june
Polar bear behaviour and physiology
- climate change impacts survival
- shrinking sea ice:
> ~30 days less to feed
> longer fasting period
> less fat deposits - study current ecological adaptations (adaptability to look for other food sources other than seals)
Polar Bear Adaptations
- body mass changes: 50% increase in bodyweight during anabolic period
- ice free period: decrease energy outputs
- female denning period
Benefits of polar bear research in a zoo setting
- controlled environment
- 365/24/7 data
- various life stages, ages, and health conditions
- individual bear can be tracked over years
Toronto zoo feeding strategy
- the toronto zoo developed a seasonal breeding program
- goal is to mimic calorie supply/flow
what does the toronto zoo feeding strategy measure?
- body condition
- body mass changes
- speed of weight loss
- % body fat
- behaviour
- blood values
Polar bear data collection
- daily diet intake
- weekly: behaviour, bodyweights
- monthly: body temperature, blood draws
How fat is a polar bear?
use SLBL (straight length body length) to measure structural mass
body composition model
- more accurate
- there is a difference between structural and storage mass
- validations of SLBL and body mass calculations using Bio-electric impedance
bio-electric impedence
- put a small current through the polar bear
- measure how long it takes for the current to pass through
- moves through water
- this tells us how much water
- the inverse will tell us how much fat
cub diet goals
- develop milk formula
- express calorie supply as a function of metabolic body weight
- provide growth data to researchers
Western Hudson Bay Bear Cubs
- cubs gain mass from birth until sea ice breakup
- lose body fat until ice returns
- still undergo structural growth during ice free period
Toronto Zoo bear cubs
- cubs gain mass continuously - didn’t think it was appropriate to make them lost fat in their first year
- housed solo
Results and Impacts with the polar bears
- body weights were comparable to wild averages of ice break (June)
- average daily gains differed
- average ME approached 4 X BMR
- impact - better understanding of how to feed cubs
Polar bear - conservation impact
- estimate calorie requirements for survival, reproduction, growth of cubs
- better understand behavioural and physiological changes
- validation of techniques used in the field
- determine what information do researchers actually need (energy budget models)
Nutritional animal well-being research
research on the Masai giraffe
- measuring microbiome changes of Saliva and Cud during rumination events
Rumen
multi chamber stomach where a lot of fermentation occurs
Giraffe and rumen health
- if we feed them the wrong diet (improper fibre), the microbiome changes
- they are not evolved to eat certain foods so their outputs change the rumen
- go through rumenal acidosis (very acidic state) which will erode the surface of the rumen
- cannot absorb nutrients anymore
Taking sample from the zoo
- take a swab of their mouth during rumination
- bolus from sloppy eating giraffe
Potential outcomes from microbe research
- validation of domestic technique in wildlife
- determine if browse can influence microbe
- first ever glimpse at giraffe microbiome
