Exam 2 Flashcards
Proteolysis
Protein Breakdown
3 major proteins in the GI tract and where they are
Pepsin (gastric stomach), Trypsin and Chymotrypsin (Duodenum)
Zymogen
An inactive substance which is converted into an enzyme when activated by another enzyme
Pepsin is produced and secreted from chief cells as ____
pepsinogen (zymogen)
Regions of protein breakdown
Stomach/abomasum and SI
Trypsin is produced and secreted from the pancreas as ___
Trypsinogen (zymogen)
Trypsin flows to ___ via ____
Duodenum, pancreatic duct
Chymotrypsin is produced and secreted from the pancreas as ____
Chymotrypsinogen (zymogen)
Chymotrypsin flows to ___ via ___
Duodenum, pancreatic duct
Microbially degradable proteins
Microbes degrade protein and use it to create microbial protein
Microbial protein
Protein that is within the microbe’s body
Rumen Degradable protein
Slowly and quickly degraded
Rumen undegradable protein
Digestible and undigestible
Quickly degradable RDP
Immediately solubilized to ammonia which is used by microbes (to make microbial protein) or absorbed as ammonia across the rumen wall
Slowly degraded RDP
Microbes have better access to this protein than quick RDP
What is the most important source of AA for ruminants?
Microbial proteins
RUP
Cannot be digested by the animal’s own enzymes at all or can be digested by the animal’s own enzymes
Non-digestible RUP
Never broken down in GI tract, excreted in feces
Digestible RUP
Digested in abomasum and SI by proteolytic enzymes similar to non-ruminants
How many macro and micro minerals are there
7 macros and at least 16 micro
Micro present in body tissue at what small concentration
<50mg/kg
Major Minerals
Calcium, Phosphorus, Potassium, Sodium, Chlorine, Sulfur, Magnesium
Micro Minerals
Iron, Zinc, Copper, Molybdenum, Selenium, Iodine, Manganese, Cobalt
Where is macromineral absorption?
Jejunum and ileum
Where is micromineral absorption?
Duodenum, Jejunum, Ileum
Functions of minerals
Enzyme activation, acid-base and water balance (Na, K, Cl), skeletal structure (Ca, P, Mg in bone, S an keratin), Fe in heme, Co in VitB12, I in thyroid hormones
Factors affecting mineral requirements
Physiological state, interactions with other minerals, tissue storage, form fed
Mineral toxicity and deficiency
Can be acute or take months to develop
What can affect mineral content in nature?
Soils, plant stage and maturity which is why east coast horses need selenium supplements
Two classifications of vitamins
Fat-soluble and water-soluble
Fat-soluble vitamins
A, D2, D3, E, K1, K2
Water-soluble vitamins
B1-B7, B9, B12, Bp?, C
Are vitamins metabolically essential?
Yes
Provitamin
Functions as vitamins only after undergoing a chemical change in the body
Vitamin A
Retinol, retinal, retinoic acid, provitamins
Important in growth, immune function, vision
Vitamin D
Important for Ca and P absorption
Can be synthesized by most animals by exposure to sunlight (no dogs, cats)
Vitamin E
Important for antioxidant function and cell signaling
Vitamin K
Required for blood coagulation
Colonic bac convert K1 (plants) to K2 (animals)
Vitamin B
Present in all plant and animal cells
Act as components of coenzyme
Closely linked to metabolic rate
Vitamin B12
Cobalt required
Essential for DNA synthesis, propionate metabolism, transfer of methyl groups in methylation reactions
How are B vitamins important in biology?
Riboflavin is necessary for structure of FAD
Vitamin A name
Retinol
Vitamin D2 name
Ergocalciferol
Vitamin D3 name
Cholecalciferol
Vitamin E name
Tocopherol
Vitamin K1 name
Phylloquinone
Vitamin K2 name
Menaquinone
Vitamin B1 name
Thiamin
Vitamin B2 name
Riboflavin
Vitamin B3 name
Niacin
Vitamin B5 name
Pantothenic acid
Vitamin B6 name
Pyridoxine
Vitamin B7 (H) name
Biotin
Vitamin B9 (M, Bg, Bc) name
Folacin
Vitamin B12
Cobalamin
Vitamin C
ascorbic acid
Functions of water
Facilitates digestion, transport and excretion of other nutrients
Total body water (TBW) content is ___ to body fat content
Inversely related
Water content lean body tissue
70-75%
Extracellular TBW
30-40%
Intracellular TBW
60-70%
Body water turnover is ___ to body water content
directly related
Factors affecting body water content and turnover (5)
Genotype, age, environmental temp, feed quantity and quality, physiological state
Ways we lose water
Feces, urine, evaporation
Water requirements affected by ___ (4)
Dry matter intake, physiological state, ambient temp, genotype
Sources of body water (5)
Drinking free water, metabolic water form nutrient oxidation, polymerization reactions, performed water in catabolized tissues, in feed
Water in feed depends on ___
feed type, processing method, storage method
Common sense dry matter equation
DM=100%-% water
Soybean material
89% DM
11% water
Whey
20% DM
80% water
Cracked corn
88% DM
12% water
High moisture corn
72% DM
28% water
Grass silage
37% DM
63% water
Grass hay
88% DM
12% water
Big dry matter equation
DM%=(weight of dried sample/as-fed weight) x 100
Approaches to assessing nutrient value in feed
Lab (Chemical, In vitro, Near-infrared spectroscopy), animal assessment
If you combust a feedstuff then the ___ material is removed and all that’s left is the ___ residue
organic, inorganic
How does ashing work and what does it do?
Sample in a muffle furnace
% ash is % mineral
Does Protein have nitrogen
yes so does NH3, urea, AA, NH4
Kjeldahl analysis
Quantitative measurement of amount of N contained in an organic substance
Crude Protein
Analyzing N content of feed therefore not analyzing it for protein, but total N
Assume protein is ___% nitrogen
16%
Fat is not soluble in ___ solvents but is soluble in ___ solvents
polar, non-polar or weakly polar
How does ether extract work and what does it mean?
Quantitative measurement of fat by extracting fat, fatty acids, and fat-soluble vits from the dried sample in organic solvent
Crude measurement of fat
What is fiber?
Carb, plant cell wall fraction
Proximate analysis
Divides feed into crude fiber, crude protein, ash, ether extract, N-free extract
Issue with Proximate system
Fiber is a carb and the plant cell wall fraction, so proximate CF doesn’t accurately represent fiber or its fractions
Natural Detergent Fiber
Represents the structural cell wall components of the plant
Acid Detergent Fiber
Represents the least digestible plant cell wall components
NDF-ADF=___
Hemicellulose
Lignin characteristics
Fiber, indigestible, in cell wall, slows down digestion in cows
What is fiber?
Portion of diet that cannot be digested by the animal (excludes microbes) (most of cell wall)
In vitro digestion simulates ___
Rumen digestion (rumen fluid) and gastric digestion (pepsin)
Near-Infrared spectroscopy (NIRS)
Used for commonly used forage
Estimate nutritive quality
Three major approaches to animal assessment
Digestibility trial, balance trial, production trial
% Digestibility=
(amount of nutrient consumed-amount in feces)/amount of nutrient consumed
Inaccuracies in the digestibility trial (3)
Fecal output includes endogenous losses, mineral loss through urine not measured, presence of potentially digestible materials
Balance Trial
same as digestion trial plus urine
gives estimate of N retention
Production Trial
Compare nutritional value of different feed ingredients
Grain:feed ratio=
Average daily weight gain/average daily dry matter intake
Goal of nutritive assessments (2)
Quantify nutritional value and composition of different feed fractions
Get some idea of how the animal’s biology will change when they consume feed
One major change that often comes along with feed changes is the change in ___
Energetic value
What is energy?
Capacity for performing work
What is bioenergetics?
Study of energy supply, utilization, and dissipation in animals
Animal’s energy requirements are based on ___
The physiologic state and metabolism of the animal
Three substrates that provide energy
Protein, lipid, carbs
First law of thermodynamics
Energy can be neither created nor destroyed
Corollary 1 and 2
Energy can be interconverted between different forms
Thermal energy cannot be converted to other forms in the body
Nutrients contain ___ which is yielded upon chemical breakdown and can be used in the body to perform chemical, mechanical, electrical or osmotic work
Chemical energy
Gross Energy (GE)
Total energy content of a given weight of feed measured as its heat of combustion by bomb calorimetry
Digestible Energy (DE)
Total digestible nutrients is the measure of energy still used directly or indirectly in the US for ruminants and swine
Metabolizable Energy (ME)
Ruminants ~ 0.82 DE
Non-ruminants >0.95 DE
Net energy (NE)
ME-heat increment of feeding
Where is fecal energy lost?
Between GE and DE
Where is urine and gas energy lost?
Between DE and ME?
Where is heat energy lost?
Between ME and NE
NE maintenance (5)
Basal metabolism, voluntary activity, thermal regulation, product formation, waste information and excretion
NE Production energy (5)
Tissue energy, lactation and egg production, conceptus, wool hair and feathers, work
What is heat increment of feeding?
Increase in heat production resulting from ingestion, digestion, and assimilation of a given amount of feed
Characteristics of ATP
Highly labile, not stored in cells, synthesized in mitochondria by oxidative phosphorylation
Where is amino acid catabolized?
Liver
Where do the VFAs go for metabolism?
Propionate goes to gluconeogenesis
Butyrate and Acetate go to fatty acid synthesis
Three reactions that cost energy
Protein Synthesis, Fat synthesis, Glucose synthesis
What is energy required for in protein synthesis?
Activation, initiation, elongation, termination
What is energy required for in fat synthesis?
Esterification
What is energy required for in glucose synthesis?
Gluconeogenesis from propionate, lactate, and glycerol
What is basal energy?
The minimum energy required to keep the animal alive (starting point for all energy requirements)
Physiological states that will increase need for energy?
Lactating, pregnant, gaining weight (growing offspring) growing wool/fiber
VFAs are produced from microbial fermentation of ___
carbs
Sources of lipids (4)
Dietary lipids, catabolism of adipose stores to FFA (lipolysis), metabolism of glucose to fatty acids (lipogenesis), VFAs (acetate, butyrate)
What is the major function of body lipid stores
Make up for deficits in dietary energy supply
Three major processes of lipid catabolism
Lipolysis of adipose tissue triglycerides, Transport of NEFA to other tissues, Fatty acid uptake and oxidation by these tissues
NEFA released from adipose tissues are transported in blood plasma in combination with ___
Plasma albumin
Plamsa NEFA concentration is ___ related to rate of fatty acid mobilization and can vary from 100-1500 umol/L
Directly related
Can most tissues take up and oxidize NEFAs?
Yes
NEFA uptake and oxidation are ___ related to plasma NEFA concentration
Directly related
Complete oxidation of long-chain fatty acids to CO2 and H2O occurs in mitochondria by a two stage process called ___
Beta- oxidation. Takes fatty acids and breaks them into two carbon chunks (acetyl CoA)
