feed composition

Question 1

what is ash?

Answer 1

mineral content of feed

Question 2

why is it important to measure ash content?

Answer 2

• nutritional labelling
• quality and taste of food
• microbiological stability
• nutritional requirements
• manufacturer processing

Question 3

what is nitrogen in dry matter?

Answer 3

approximate amount of protein content

Question 4

what two assumptions are made for the kjeldahl analysis?

Answer 4

1. all nitrogen is protein
2. all protein contains 16% nitrogen

Question 5

how do you calculate % crude protein?

Answer 5

(n in sample x 6.25)/wet weight of sample

x 100

Question 6

how do you calculate the ratio of nitrogen in protein

Answer 6

100% (total protein)/% of nitrogen

for kjeldahl it would be 16% nitrogen

Question 7

how do you calculate % crude fibre?

Answer 7

(wt of ash + crude fibre) - (wt of ash)/wet weight of sample

x 100

Question 8

how do you calculate % ash?

Answer 8

weight of ash/wet weight of sample

x 100

Question 9

what is crude fibre?

Answer 9

• mainly cellulose and lignin, what remains after processing in the proximate analysis
• not the same as dietary fibre which is all fibre in a food

Question 10

what is the difference between insoluble and soluble fibres?

Answer 10

• insoluble: remains intact through intestinal tract, doesn’t dissolve in water
• soluble: forms gel, does dissolve in water

Question 11

what are examples of insoluble and soluble fibres?

Answer 11

• insoluble: cellulose, lignin, hemicellulose
• soluble: pectins, gums, mucilages

Question 12

what is the van soest method?

Answer 12

fibre analysis method that can differentiate between insoluble fibres, determine fermentable and non fermentable CHOs, but not used for human food since it poorly differentiates sugars, starches, and soluble fibres

Question 13

what is the southgate method?

Answer 13

fibre analysis that provides info about sugars, starch, and various fibres, useful for human nutrition, but doesn’t differentiate sufficiently between various insoluble fibre components (not used in agriculture)

Question 14

what is nitrogen free extract?

Answer 14

digestible CHO, estimates starch and sugar content

Question 15

how do you calculate % NFE?

Answer 15

100 - (% moisture + % crude fat + % ash + % crude protein + % crude fibre)

Question 16

what info can’t the proximate analysis provide?

Answer 16

• digestibility
• specific AAs, minerals, lipids, CHOs

Question 17

what are essential nutrients?

Answer 17

chemical that is required for metabolism, can’t be synthesized rapidly enough or at all to meet the needs of an animal

Question 18

when do nutritional deficiencies occur?

Answer 18

when a person’s nutrient intake consistently falls below the recommended requirement

Question 19

what is the difference between a deficiency and a nutritional requirement?

Answer 19

treating deficiency prevents disease while meeting nutritional requirements ensure optimal health

Question 20

what are daily values in nutrition facts based on?

Answer 20

2000 calorie a day diet, made using dietary reference intakes

Question 21

what is a dietary reference intake (DRI)?

Answer 21

term that refers to a set of reference values for nutrients: EAR, RDA, AI, UL

Question 22

what is estimated average requirement (EAR)?

Answer 22

requirements in which the needs of 50% of the population are met (middle of normal distribution)

Question 23

what is recommended dietary allowance (RDA)?

Answer 23

• requirements in which the needs of 97% of the population are met
• RDA = EAR + 2 standard deviations

Question 24

what is tolerable upper limit (UL)?

Answer 24

the highest level of continuous daily nutrient intake that causes no risk of adverse effects

Question 25

what is adequate intake (AI)?

Answer 25

• based on much less scientific data, used when not enough evidence available to establish an EAR and RDA
• determined based on intake in healthy people who are assumed to have an adequate nutritional status
• expected to meet or exceed the needs of most individuals (RDA)

Question 26

what are the 4 characteristics of a nutritious diet?

Answer 26

• adequate: enough calories, essential nutrients, and fibre to keep you healthy
• moderate: no excess consumption of calories or a certain food/food group than recommended
• balanced: nutrient dense foods
• varied: wide selection of foods to get necessary nutrients

Question 27

what are the nutrient classes and what do they include?

Answer 27

• organic (contains carbon): CHOs, lipid, protein, vitamins
• inorganic: minerals, water

Question 28

which nutrients are considered macronutrients and micronutrients?

Answer 28

• macronutrients: CHOs, lipids, proteins
• micronutrients: vitamins, minerals, water

Question 29

what are anabolism and catabolism?

Answer 29

• anabolism: intake of energy via nutrients
• catabolism: breakdown/usage of energy

Question 30

what are the functions of water?

Answer 30

• solvent in biochemical reactions
• catabolism (hydrolysis)
• maintains vascular volume
• nutrient transport
• temperature regulation

Question 31

what is water toxicity?

Answer 31

when water intake exceeds the kidner’s ability to process, hyponatremia occurs where there is low sodium in the blood