ANFS 251 Exam 2

Dr. Lesa Massarotti, Spring 2026, University of Delaware

Protein

A macronutrient composed of amino acids; essential for growth, maintenance, and all life processes.

Amino Acid

The basic building block of proteins, containing an amino group, a carboxyl group, and a carbon skeleton.

Protein Synthesis

The process by which cells assemble amino acids into proteins according to DNA instructions.

Enzyme

A protein that catalyzes chemical reactions, including digestion and metabolism.

Hormone

A signaling protein or compound that regulates growth, metabolism, and physiological processes.

Immunoglobulins

Proteins involved in immune defense against pathogens.

Structural Proteins

Insoluble proteins such as hair, wool, feathers, hooves, and skin that provide protection and structure.

Soluble Proteins

Proteins such as plasma proteins that dissolve in body fluids.

DNA (Deoxyribonucleic Acid)

Genetic material that codes for the sequence of amino acids in proteins.

Essential Amino Acids

Amino acids that animals cannot synthesize in adequate amounts and must obtain from the diet.

Nonessential Amino Acids

Amino acids that can be synthesized by animal tissues in adequate amounts.

Dietary Essential

Refers to nutrients that must be supplied in the diet.

Limiting Amino Acid

The amino acid present in the least amount relative to the animal’s requirement, limiting protein synthesis

First Limiting Amino Acid

The amino acid that first restricts protein synthesis when deficient.

Lysine

An essential amino acid commonly deficient in cereal grain–based diets.

Methionine

An essential amino acid often limiting in poultry diets.

Tryptophan

An essential amino acid that may limit protein synthesis in some diets.

Protein Quality

A measure of how well a protein’s amino acid profile meets an animal’s requirements.

Animal Protein Sources

Protein feeds derived from animals, such as milk by-products and fish meal.

Plant Protein Sources

Protein feeds derived from plants, such as soybean meal.

Soybean Meal

A high-quality plant protein supplement widely used in animal diets.

Oilseed Meal

Protein-rich by-products remaining after oil extraction from seeds.

Microbial Protein

Protein synthesized by microorganisms in the rumen or large intestine.

Non-Protein Nitrogen (NPN)

Nitrogen sources such as urea that can be used by rumen microbes to synthesize protein.

Ruminant (Proteins)

An animal with a rumen that relies on microbial fermentation to meet protein needs.

Monogastric Animal (Proteins)

An animal with a single-chambered stomach that requires dietary essential amino acids.

Digestibility (Proteins)

The proportion of dietary protein that is broken down and absorbed as amino acids.

Pepsin

A stomach enzyme that begins protein digestion by breaking proteins into polypeptides.

Trypsin

A pancreatic enzyme that breaks polypeptides into smaller peptides.

Peptidase

An enzyme that breaks peptides into individual amino acids.

Polypeptide

A chain of amino acids produced during protein digestion.

Biological Value (BV)

The proportion of absorbed amino acids retained by the body for protein synthesis.

Protein Efficiency Ratio (PER)

A measure of weight gain per unit of protein consumed.

Net Protein Value (NPV)

A measure combining protein digestibility and biological value.

Associative Effect

Improved amino acid balance achieved by blending different feedstuffs.

Excess Protein

Protein consumed beyond requirements that is metabolized for energy.

Deamination

Removal of the amino group from an amino acid during metabolism.

Urea

A nitrogen-containing waste product excreted in urine.

Protein Deficiency

A condition where dietary protein or amino acids are insufficient.

Signs of Protein Deficiency

Poor growth, low milk or egg production, infertility, and reduced feed efficiency.

Blood Urea Nitrogen (BUN)

A blood measurement used to assess protein status.

Protein Requirement

The amount of dietary protein needed to meet maintenance and production needs.

Growth Stage Effect

Protein requirements decline as animals mature.

Lactation (Protein)

A physiological state with increased protein requirements.

Protein Toxicity

Rare adverse effects from excessive protein intake, usually avoided with adequate water.

Trypsin Inhibitor

A compound in raw soybeans that interferes with protein digestion.

Feed Cost (Protein)

Protein is typically the most expensive component of animal diets.

Muscle Tissue (Protein)

Body tissue rich in protein, requiring adequate dietary protein for maintenance.

Egg Production (Protein)

A physiological state with increased protein and amino acid requirements (avians)

Lipids

A class of organic compounds insoluble in water but soluble in organic solvents; includes fats, oils, sterols, and phospholipids

Fats

Lipids that are solid at room temperature, typically composed of saturated or long-chain fatty acids.

Oils

Lipids that are liquid at room temperature, usually rich in unsaturated or short-chain fatty acids.

Energy Density (Lipids)

The amount of energy provided per unit weight of a nutrient; fats provide about 2.25 times more energy than carbohydrates

Triglyceride

The primary form of fat in plants and animals, composed of three fatty acids attached to a glycerol molecule

Fatty Acids

A chain of carbon atoms with a carboxyl group; the basic component of fats.

Saturated Fatty Acids

A fatty acid with no double bonds between carbon atoms.

Unsaturated Fatty Acids

A fatty acid containing one or more double bonds.

Monounsaturated Fatty Acids

A fatty acid containing one double bond.

Polyunsaturated Fatty Acids

A fatty acid containing two or more double bonds.

Short-Chain Fatty Acids

Fatty acids with fewer carbon atoms that are more water soluble and rapidly metabolized

Long-Chain Fatty Acids

Fatty acids with many carbon atoms that are transported via the lymphatic system.

Glycerol

A three-carbon molecule that forms the backbone of triglycerides.

Phospholipids

Lipids containing phosphorus that are major components of cell membranes.

Sterols

A class of lipids including cholesterol and vitamin D with important biological roles.

Cholesterol

A sterol involved in cell membrane structure and hormone synthesis.

Lipoproteins

Complexes of lipids and proteins that transport lipids in the blood.

HDL (High-Density Lipoprotein)

A lipoprotein that transports cholesterol from tissues to the liver for excretion.

LDL (Low-Density Lipoprotein)

A lipoprotein that transports cholesterol to tissues; high levels are associated with plaque formation

Bile

A digestive secretion produced by the liver that emulsifies fats in the small intestine.

Emulsification

The process of breaking fat into small droplets to increase surface area for digestion.

Lipase

A pancreatic enzyme that breaks triglycerides into fatty acids and glycerol.

Small Intestine (Fats)

The primary site of fat digestion and absorption in monogastric animals.

Lymphatic System (Lipids)

A transport system that carries absorbed long-chain fatty acids to the bloodstream.

Fat-Soluble Vitamins (Lipids)

Vitamins A, D, E, and K that require dietary fat for absorption.

Adipose Tissue

Body tissue specialized for fat storage.

Energy Reserve (Fats)

Stored fat used to supply energy during periods of inadequate intake.

ATP (Adenosine Triphosphate)

The primary energy currency of cells.

Ketosis

A metabolic disorder caused by excessive ketone production during fat metabolism.

Ketone Bodies

Compounds produced during fat metabolism that can serve as alternative energy sources.

Rumen Microorganisms (Fats)

Microbes in ruminants that alter dietary fatty acids through biohydrogenation.

Biohydrogenation

The microbial saturation of unsaturated fatty acids in the rumen.

Protected Fat

Dietary fat treated to resist rumen microbial alteration.

Essential Fatty Acids

Fatty acids that animals cannot synthesize and must obtain from the diet.

Linoleic Acid

An essential omega-6 fatty acid with 18 carbons and two double bonds.

Linolenic Acids

An essential omega-6 fatty acid with 18 carbons and three double bonds.

Omega-6 Fatty Acids

Fatty acids with the first double bond six carbons from the terminal end.

Omega-3 Fatty Acids

Fatty acids with the first double bond three carbons from the terminal end.

Cell Membrane Structure

The role of lipids in maintaining membrane integrity and function.

Hormone Precursors

Lipids that serve as building blocks for hormone-like compounds.

Dietary Fat Content

The amount and type of fat included in animal diets.

Carcass Fat Composition

The fatty acid profile of body fat influenced by diet, especially in monogastrics.

Melting Point

The temperature at which fat becomes liquid, influenced by saturation level.

Feed Cost (Lipids)

Lipids are among the most expensive energy sources in animal diets.

Energy Utilization (Lipids)

The process by which nutrients are metabolized to supply ATP.

Vegetable Oil Sources (Lipids)

Plant-derived oils such as corn oil and soybean oil.

Animal Fat Sources

Fats derived from animals, such as tallow and poultry fat.

Lipid Deficiency

A rare condition but may involve essential fatty acid deficiency, especially in poultry.

Fat Digestibility

The proportion of dietary fat absorbed by the animal, generally high for oils.

Vitamins

Organic compounds required in very small amounts for normal metabolic function, growth, and health.

Water-Soluble Vitamins

Vitamins that dissolve in water and are not extensively stored in the body; excess amounts are excreted in urine.