Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Sherry ANBI 411 > Lecture 22 and 23 > Flashcards

Lecture 22 and 23 Flashcards

1
Q

How does feed cost and net income for pork producers in Saskatchewan relate?

A

They’re inversely related

feed is the farmers biggest cost (63% in 2020)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Does production drive nutrition or does nutrition drive production?

A

In dairy cows, early lactation, feed intake doesn’t matter they will produce milk no matter what. Mid to late lactation, feed intake determines milk production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Definition of hunger, preference, selection, appetite, palatability

A
  • Hunger - a strong need or desire for food
  • Preference - what animals select given minimal physical constraints
  • Selection - preference modified by environmental circumstances
  • Appetite - an instinctive physical desire, especially one for food or drink
  • Palatability - acceptable to the taste; agreeable in flavour to be eaten- acceptable or agreeable to the mind
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Definition of satiety, orexigenic, anorexigenic, adlibitum, pica

A
  • Satiety - the condition of being full or gratified beyond the point of satisfaction
  • Orexigenic - increasing or stimulating the appetite
  • Anorexigenic - producing anorexia, an agent that diminishes or controls the appetite
  • Ad libitum - ‘at one’s pleasure’ or food is available at all times
  • Pica - is the persistent craving and compulsive eating of nonfood substances (lack of phosphourous or boredom)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are examples of farm animals not being fed ad libitum?

A
  • Sows in gestation are limit fed to avoid too high of back fat before and after farrowing
  • Broiler breeders
  • smetimes companion animals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the two main categories of feed supply?

A
  1. Diet is supplied (pigs, chickens, dairy cows) - animal has no choice, responsibility of provider to meet the nutrient requirements
  2. The animal is responsible for feed (nutrient) selection (animals on range)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the mechanisms of feed intake control?

A
  • Feedback from the gastrointestinal tract
  • Metabolites and hormones
  • Central nervous system
  • Learning about food: conditioned preferences and aversions
  • Diet selection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are factors that would affect feed intake?

A

Feed
* availability
* Quality

Environment

Animal
* Integration with the CNS
* Gastrointestinal
* Adipose tissue
* Hormones
* Metabolites
* Learning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is feed intake control?

A

Short-term
* Meal size
* Frequency of meals

Long-term
* Homeostasis
* Homeorhesis (adaptive state-new state of metabolism)
* Maintenance of body weight and adiposity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How to measure food intake?

A
  • Simplest - measure feed before and after eating
  • actually measuring disappearance
  • Marker dilution - intake determined from ratio between marker in the feed and the feces (must know feed digestibility)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is eating behaviour and feed availability like in swine?

A
  • Grow finish pigs typical consume 10 to 20 meals per day
  • smaller pigs eat more meals
  • increasing the number of pigs accessing a feeder space will reduce the number of meals
  • pigs spend about 40% less time eating pellets than mash
  • eating behaviour is variable
  • Pigs can maintain feed intake levels despite varying environmental conditions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the equation for food intake for grazing animals?

A

food intake, g/d = grazing time (min/d) x biting rate (n/min) x bite size (g)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are methods for finding food intake for grazing animals?

A
  • using digestibility and fecal collection
  • difference between forage mass before and after grazing
  • feeding behaviour, bits, biting rate and grazing time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does environment (stress) affect feed intake?

A
  • Most work conducted with lab animals
  • Response dependent upon duration of stressor and whether the stress is physical or physiological
  • In rats, mild stressors such as a pinch will stimulate feeding and drinking following the stress
  • More extreme stress inhibits feed intake
  • body weight reductions observed with stress only slowly regained
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are some issues with feed quality?

A
  • High or low energy concentration
  • Toxic compounds
  • Nutrient deficiencies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What affects feed intake in dairy heifers?

A
  • Heifers spend only about 3 to 3.5 h/day consuming feed
  • However, they tend to synchronize their behaviour, - which increases the bunk space required
  • Initiation of feeding by one animal, encourages others to feed
  • Feeding occurs at sunrise, sunset and when fresh feed is delivered
  • If competition increases, synchrony may break down
  • Increasing pen stocking density and decreasing feed bunk space (from 0.81 to 0.20 m per heifer) decreased time spent eating by 26%
  • However no effect on DMI
  • Heifers compensated by eating faster
  • Competition results in fewer meals per day which are larger and longer(rumen pH declines with increasing meal size)
17
Q

What is the Response to dietary digestible energy concentration in growing pigs fed cereal-based diets

A
  • Feed intake decreased as we increased energy
  • no significant changes in gain
  • energy intake was relativly the same

formulate the diet based on cost

usually around 3.2 and 3.3 normally

18
Q

Swine and chickens ability to compensate forenergy changes in diet

A

Swine
* “bulkiness” of a feed may limit the ability of a pig to consume sufficient amounts to meet desired nutrient intake
* In young pigs, up to about 20 kg BW, physical capacity to ingest and digest feed limits intake
* Growing pigs, - up to about 50 kg BW, can’t compensate for reductions in diet DE below 3350 kcal/kg

Chickens
* Inflation of a balloon in the crop depressed intake,
* But…“chickens are unable to accurately alter feed intake in response to dietary energy levels”
* Meeting the chicken’s energy requirements promotes maximum protein accretion”

19
Q

Feeding behaviour, food intake of lactating dairy cows fed diets based on silage of high or low DM content

A
  • Forage DM intake greater with increased DM
  • Shorter times to ingest and ruminate
  • Benefits seen in milk yield
  • Lower gut fill probably allowed larger meal sizes before gut fill became a constraint
20
Q

What do ruminants have to indicate the full feeling?

A
  • Gastrointestinal receptors
  • Ruminant forestomachs innervated by branches of the vagus and splanchnic nerves
  • Mechanoreceptors in the epithelial lining of the reticulorumen
    – Function also to control motility
  • Chemoreceptors in the epithelial lining of the reticulorumen
21
Q

Do animals “taste” food the same as humans?

A

– “dietary nutrients elicit taste by stimulating the taste machinery in the tongue (taste buds, taste receptors, nerves) which in turn stimulate the gustatory (concerned with the sense of taste) cortex in the brain
– Current scientific evidence shows that taste receptors are also acting as nutrient sensors away from the tongue, continuously surveying the nutritional status of the animal
– Our understanding of the role of taste receptors in non-oral tissues is “-just starting to be understood”

22
Q

What are the 6 tastes now recognized?

A
  • Sweet
  • Umami
  • Fat
  • Salt
  • Sour
  • Bitter
23
Q

Central nervous system and the
control of feed intake

A
  • Brain “collects” information from the sensors and receptors in the digestive tract and tissues
  • Lesions in the ventromedial hypothalamus (VMH) cause over-eating and obesity
  • Lesions in the lateral hypothalamus (LH) causes extreme anorexia
24
Q

What is the largest endocrine organ in the body and what does it do?

A
  • GI tract represents the largest endocrine organ in the body, containing enteroendocrine cells (EEC) throughout
  • EECs sense ingested nutrients and release an array of peptides and hormones that act as autocrine, paracrine or endocrine regulators of digestive function, glucose homeostasis or energy balance
  • CCK- cholecystokinin
  • GIP – glucose dependent insulinotropic polypeptide
  • GLP- 1 – glucagon-like peptide 1 (ozempic - weight loss used in diabetes increases insulin and decreases appatite)
  • Apo-A-IV – apolipoprotein
  • PYY – peptide YY
25
Q

Summary of (some) appetite regulating molecules in pig, chicken, ruminant (GLP-1, Leptin, Ghrelin, CCK, Glucose, Lipid, SCFA)

A

GLP-1
* decrease in pig, cow, chicken

Leptin
* decrease in pig, cow, chicken(?)

Ghrelin
* increase in pig, cow
* decrease in chicken

CCK
* Decrease in pig, cow
* ckicken unknown

Glucose
* decrease in pig

Lipid
* decrease in pig, cow

SCFA
* decrease in pig, cow

26
Q

What is leptin?

A
  • a hormone regulating weight
  • In 1959 an experiment was reported in which 2 rats were parabiosed (blood supply connected) and one was made obese by lesioning the VMH
  • This animal became obese, and its partner stopped eating
  • Evidence for a circulating satiety factor
  • Similarly when the genetically obese ob/ob mouse was parabiosed with a lean mouse, the obese mouse lost weight.
  • The obesity was caused by an absence of a circulating factor, eventually discovered to be leptin.
27
Q

leptin continued

A
  • Plasma concentrations of leptin highly correlated with body fat mass in sheep, cattle, pigs, horses
  • Food deprivation causes a dramatic decrease in plasma leptin (ie. 24 hour)
  • Leptin, produced in cultured adipocytes, responsive to availability of glucose and fatty acids
  • Infusing insulin, increased circulating leptin
  • Can conclude that circulating leptin signals both fat stores and energy intake
  • Question: if leptin suppresses feed intake, - and leptin is produced in relationship to adipose tissue, then why do fat animals continue to eat?? - have to be genetically obese
28
Q

What is the interesting fact about hibernation?

A
  • White adipose tissue (WAT) mass is vastly increased in hibernators prior to entering hibernation
  • Although few studies have been done it appears that leptin may be dissociated from WAT levels prior to hibernation to allow WAT mass increases
  • High leptin levels have been shown to inhibit torpor in several species
29
Q

What is Ghrelin?

A
  • Proposed as a signal to stimulate feed intake
  • Produced by the pancreas and cells lining the stomach
  • Probably acts on the hypothalamus
  • Circulating levels increase before anticipated meals
  • Emptying the rumen increased circulating ghrelin
30
Q

What is Cholecystokinin (CCK)?

A
  • synthesized in the mucosal epithelium of the small intestine
  • Suppresses feed intake
  • Very responsive to lipids
31
Q

What are Other satiety signals produced by the small intestine?

A
  • Bombesin- release of CCK etc
  • Glucagon-secreted by the pancreas in response to low blood glucose
  • GLP-1, GLP-2 (glucagon-like peptide) incretins, enhance insulin action
  • Somatostatin – growth hormone inhibiting hormone, inhibits insulin and glucagon secretion
  • Enterostatin- peptide regulating fat intake
  • Peptide YY -released in response to feeding, reduces appetite

Sherry ANBI 411 (32 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions