Description
Intro to animal science study guide for 2nd exam
Nutrition & the early years
first nutritional study evidence in the Book of Daniel (25002400 years ago)
Hippocrates made the first references to the medicinal properties of food and that proper amounts of nourishment was key to be healthy
origins of nutrition as a science began during the chemical revolution in the late 1700’s Antoine Lavosier defined life as a chemical process
1886 Francois Magendie discovered diversity was key to proper nutrition by conducting experiments with dogs, and only feeding some one nutrient category which passed away and others all the nutrient categories which lived.
Weende identified food components in the 1860’s, also providing approximant analysis of feed
Nutrition: The sum of the processes in an animal by which feed (or food) substances are consumed, metabolized, assimilated, and waste products eliminated ULTIMATELY, Supports growth, tissue maintenance and repair, and extension of products
We also discuss several other topics like How is corynebacterium diphtheriae treated?
Food is an item that supplied nutrients in its natural state
feed is food that is supplied to an animal system (often processed)
Nutrients: Any chemical element or compound in the diet that supports maintenance of life processes and extension of growth, reproduction, and lactation.
also something that is required to support cellular needs and thereby support work, maintenance and repair of tissues.
Nutrient classifications: Water, Protein (crude Protein), Carbohydrates, Lipids, Vitamins, Minerals (ash)
vitamins were not originally a nutrient category, because they were not discovered until 1880’s by Christian Eijkman.
protein is based off the amount of nitrogen in the feed
essential or indispensable nutrients are required I the animals diet, because the body doesn’t make enough of it on its own
nonessential or dispensable nutrients are not required in the diet If you want to learn more check out What were the mycenaeans known for?
water is the most over looked nutrient category, it makes up 5075% of the adult body and up to 90% of a newborns body, as well as 6065% of the mass of a cell.
as little as the loss of 10% of water can be deadly
Water functions
1. Required for reactions of the body
2. Maintains constant body temperature
universal solvent
transport medium and a diluent and required for the transport of semisolid digests in the gastrointestinal tract.
transports blood, tissues, cells and exogenous secretions (urine and sweat) used to keep the body cool by evaporation (sweating and panting) We also discuss several other topics like Do xenophanes believe in god?
Water loss from the body is constant, and animals must constantly consume water in someway to remain hydrated, it could be via the food they consume or drinking fluids directly.
urination is the primary method of water loss
Nutrient functions: Structural components, Sources of energy, Regulatory functions
Energy is a function of the carbon skeleton: Protein – 5.65 kcal/g; Carbohydrates – 4.15 kcal/g; Lipids – 9.45 kcal/g
Carbohydrates:
primary source of energy, but not a required dietary essential.
Categorized as simple or complex
Simple carbs are referred to as sugars and are classified as monosaccharides or disaccharides
Monosaccharides include glucose, galactose and fructose. We also discuss several other topics like What is the meaning of a wash fixture?
glucose is the primary source of energy for most cells
Disaccharides include maltose, sucrose and lactose
Complex carbs include the polysaccharides: starch and fiber.
Starch include polysaccharides like amylose which is a straight line of glucose and amylopectin which is branched.
Fiber include polysaccharides like cellulose, hemicellulose, pectin and lignin.
Metabolism: the process by which the body uses the nutrients to support the needs of living systems Don't forget about the age old question of What is responsible for forming the nucleolus?
Catabolism: the process of the body breaking down nutrients
Anabolism: the process of building new compounds
Calorimetry: Measure of energy If you want to learn more check out What is the meaning of cephalopods?
1) calorie = amount of heat required to raise the temperature of one gram of water from 14.5 to 15.5 °C
• 1000 cal = 1 kcal (Cal) = 4.184 kjoules
• Food labels
• Measure of potential energy!
Concept
1) Combustion of a sample results in energy manifested as heat
2) A rise in water temperature reflects transfer of energy from the food to heat 3) A onedegree change in temperature of one gram of water equals one calorie
Lipids:
Lipids as fatty acids are the most concentrated source of energy, source of essential fatty acids, integral components of cell membranes and carriers of the fat soluble vitamins.
95% of dietary lipids come from animal products, cereal grains and oils supplied in the form of triglycerides
Triglyceride have three fatty acids attached to a glycerol back bone
Adipose tissue is a form of energy reserve, and the storage of lipids is basically limitless unlike glucose.
Most fatty acid chains from animals are strait, with even number of single carbon bonds. this fat is saturated, so is solid at room temperature.
Unsaturated fat is liquid at room temperature, and have one or more double bonds. It can occur as cis or trans.
Most trans fats are manmade through hydrogenation and have been proven to have negative effects on the body. Natural occurring trans fats have not shown the same effect.
The difference between cis and trans fats are the placement of the hydrogen: in cis, the hydrogen is adjacent to the double bond are oriented in the same direction, and in trans the hydrogens are adjacent to the double bond are oriented in the opposite direction
*be sure to look at figure 4.1.11 to see the visual difference between saturated, unsaturated and trans fatty acids*
The most important unsaturated fatty acids for animals are linolenic acid, linoleic acid
Cats and other carnivores also require arachidonic acid
Ruminants have no defined dietary essential fatty acid requirements.
Phospholipids are another kind of fatty acid, but contain two fatty acid tails and a phosphate group.
Proteins:
product of gene transcription and are the molecules of enzymecatalyzed reactions, muscles contraction, metabolic regulation, and immune function,
All cells synthesize proteins
Provide energy in time of need (only 4 Kcal/g when catabolized)
Are made of amino acids
Amino acids have a central carbon to s hydrogen, a carboxylic acid group, amine group and a side chain (see figure 4.1.13)
Peptide bonds hold them together, and multi peptides are called poly peptides Primary structure of a protein is the linear sequence of the amino acids
Secondary structure is the result of local folding due to interactions between closely located amino acids
Tertiary structures involve more distant interactions with polypeptide chains
Quaternary stricter results from the interactions between different peptides chains nonprotein “amino” acids
Obligatory carnivores have an additional requirement for taurine
Insects may have an additional requirement for carnitine
Vitamins: group of organic substances that are required in relatively small amounts and are essential for life
1900’s is the start of the vitamin revolution.
Stephen Babcock is credited to discovering vitamin A, by doing studies with cows Fat Soluble
Vitamin A Vitamin D Vitamin E Vitamin K
Vitamin A can have a high toxicity, which is why we can’t eat polar bear livers Beta carotene can be used to fulfill vitamin A requirement in some animals
Vitamin D can be converted from sun’s radiation but should not be relied on as the main supply of vitamin D
Water Soluble
Ascorbic acid (vitamin c), Niacin, Biotin, Choline, Cobalamin, Folic acid, Pantothenic acid, Pyridoxine, Riboflavin, thiamin
Most animals make Vitamin C on their own. Guinea pigs, chickens, bats, and humans do not make their own vitamin C
Minerals: an inorganic solid crystalline chemical element that are required for all animals.
Macromolecules are required in greater amounts and include calcium, phosphorus, magnesium, potassium, sodium, chloride and sulfur
Micro minerals or trace minerals are needed, but in lesser amounts. They include numerous minerals, but some examples are chromium, cobalt, copper, zinc, iron, etc.
Modern Cell Theory proposed by Schwann and Schleiden
1. All living things are composed of cells
2. The cell is the fundamental unit of structure and function in all living things 3. All cells come from preexisting cells
Robert Hooke discovered cells
Deoxyribonucleic acid (DNA)
Universal material of heredity
Three chemical components: 1) Phosphate. 2) deoxyribose (sugar backbone), 3) nitrogenous bases
Complementary base pairing
Chargaff’s rules: A: T and G:C
Genes
Genes Sequences of nucleotides that serve as
precursors to proteins Direct all processes of the cell – Blue Print of Life
Inheritance: Transfer of genetic material
Inheritance is the result of the mixing of blood, contributed by each parent of the individual
Mendel’s observations
1. Many inherited characteristics (traits) are under the control of two distinct factors (genes) – one coming from the male parent and the other from the female parent
2. A trait may not show up in an individual, but be passed to the next generation Organization of a gene
Homologous Chromosomes Chromosomes coded
with “matching” information from the male and female
Locus Location of the gene Alleles Given copy of a gene Homozygous Gene copies are the same Heterozygous Gene copies differ
Two Laws of Inheritance
Principles of
Segregation only one
randomly chosen allele is found within a gamete
Independent Assortment
Separation of chromosomes (thus genes) is independent
Absurd to real expression of traits:
Dominant allele (gene) “overpowers” and prevents expression of the gene at the corresponding loci on the homologous chromosome
Recessive allele corresponding gene that is “masked” by the dominant allele at the corresponding loci
Nonclassical dominance
Codominance or Nodominance Neither:
allele masks the other and both are expressed
Incomplete dominance or Partial dominance:
An allele is expressed in a dose dependent manner
Sex related inheritance
Sex linked Expression of a gene that is located on the X chromosome Sex limited Trait is limited to gender
Sex influenced Trait is influenced by gender, an allele that is dominant in one sex is recessive in the other sex.
Some variation cannot be predicted
• Crossingover
– Occurs during initial meiosis
• Mutation
– Insertion, deletion, substitution of nucleotide – New protein: Better performance/Worse performance
Animal breedingApplied genetics
Objective produce animals that excel for desired traits while eliminating/minimizing occurrence of undesirable traits. Involves culling of less desirable animals and selection of superior replacements.
Phenotype Observable measures of traits
qualitative traits
Subjective measure
descriptive or categorical and classified into groups: red or black angus; horned or polled sheep
Controlled by a few genes Progress of selection not difficult
Quantitative traits
Objectively (numerically) measured Milk production, loin eye area, weight, speed Polygenic Controlled by
many genes, often on different chromosomes, each contributing a small effect
Tools for genetic change
Selection Obtaining a desirable
phenotype through choosing animals for mating
Mating Pairing of males and females
Phenotypic Selection
PHENOTYPE = GENOTYPE + ENVIRONMENT
Climate Health Feeding Stress
Facilities…
Female parent Male parent
Quantitative traits Greater environmental
influence, variable heritability
Qualitative traits Less environmental
influence, greater heritability
Predicting genetic progress
Selection Differential Phenotypic advantage of
chosen parents. Superiority of selected animals compared to the herd average for a particular trait.
Heritability of the trait Proportion of phenotypic
variation that can be passed from parent to offspring
Generation interval Average time required to
replace one generation with the next. The shorter the generation interval the greater rate of change.
Genetic change per year
Heritability x Selection Differential Generation Interval
Genomic based selection
Traditional animal breeding requires assigning a breeding value based on desired production traits with expectation the traits are inherited within offspring. MAS Marker assisted selection allows identification of regions of DNA associated with a trait SNPS single nucleotide polymorphisms can be identified in animals that are identified by key selection traits. The presence of SNPs allows prediction of breeding value. Unlike MAS, SNPs scan the entire genome not just predetermined regions.
Tools for genetic change
Selection Obtaining a desirable
phenotype through choosing animals for mating
Mating Pairing of males and females
Mating depends on desired results
Increased homozygosity Increase
predictability of progeny as future breeding animals by decreasing variation of contrasting alleles (Aa)
Increased heterozygosity Increase
performance of progeny for production by increasing variation of contrasting alleles (Aa). Can result in hybrid vigor (heterosis)
Outbreeding Mating of unrelated animals within lines & breeds or between breeds. Increases variation, increases heterozygosity, increases productivity through hybrid vigor. Greatest effects in lowly heritable traits and within the first generation of crossbreeding.
Inbreeding Intensive breeding of close relatives practiced to maintain breed standards and achieve predictability of offspring. Decreases variation, increases homozygosity of desired and recessive gene
Molecular genetics
Transgenic organisms The purposeful
manipulation of an organism’s DNA for the
production of organisms with genomes that cannot be created through traditional breeding