Aquatic Animal Aquatic Animal NutritionNutrition

FAS 2240CFAS 2240CLecture 1: Lecture 1:

Introduction Introduction

Course SyllabusCourse Syllabus

Study of aquatic animal nutrition: bioenergetics digestion/digestive anatomy/metabolism nutrient classes/sources/requirements formulation/feedstuffs manufacturing processes practical pond feed management

SyllabusSyllabus Animals covered: variety of finfish and crustacean

species textbook: none are current or adequate also, various reprints of peer review journal

articles on reserve:

De Silva, S.S., and T.A. Anderson, 1995. Fish nutrition in aquaculture

Lovell, T., 1989. Nutrition and feeding of fishD’Abramo, Conklin and Akiyama, 1992.

Crustacean NutritionHalver, J., 1988. Fish NutritionMaynard and Loosli, 1969. Animal Nutrition

Today’s Lecture: Today’s Lecture: 8/25/058/25/05

Part 1: Introduction (Maynard et al.; Lovell) What is nutrition??? History of nutrition Nutrition today Nutrient essentiality

Part 2: The animal body and its food (Maynard, et al.; Lovell) Aquatics vs. terrestrials

What is Nutrition?What is Nutrition? NutritionNutrition:: the provision of all indispensable the provision of all indispensable

nutrients in adequate amounts to insure proper nutrients in adequate amounts to insure proper growth and maintenance of body functionsgrowth and maintenance of body functions

involves various chemical reactions and involves various chemical reactions and physiological transformations which convert physiological transformations which convert foods into body tissues and activitiesfoods into body tissues and activities

involves ingestion, digestion and absorption of involves ingestion, digestion and absorption of various nutrientsvarious nutrients

transport into cellstransport into cells removal of unusable elements and waste removal of unusable elements and waste

products of metabolismproducts of metabolism

History of History of Nutrition I.Nutrition I.

LavoisierLavoisier is generally credited as being is generally credited as being the “father” of nutritionthe “father” of nutrition

until the first quarter of 19th Century, we until the first quarter of 19th Century, we thought the nutritive value of food thought the nutritive value of food resided only in one componentresided only in one component

near the end of the 19th Century near the end of the 19th Century research started to focus primarily on the research started to focus primarily on the need for protein, lipids and carbohydratesneed for protein, lipids and carbohydrates

minerals were considered important, but minerals were considered important, but their essentiality was unknowntheir essentiality was unknown

History of Nutrition History of Nutrition II.II.

Tremendous expansion in the 20th Century Tremendous expansion in the 20th Century with the discovery of vitamins, role of amino with the discovery of vitamins, role of amino acids, more mineralsacids, more minerals

the body is now known to need more than 40 the body is now known to need more than 40 nutrients for normal growth and maintenancenutrients for normal growth and maintenance

what have been the reasons for these what have been the reasons for these advances???advances???

Human nutritional/health problemsHuman nutritional/health problems also, basic studies of the functioning of the also, basic studies of the functioning of the

animal organism supplemented researchanimal organism supplemented research

History of Nutrition History of Nutrition III.III.

Example of historical nutritional research:Example of historical nutritional research: heifers fed wheat-based diets produced heifers fed wheat-based diets produced

calves at lower rates than those fed corn calves at lower rates than those fed corn dietsdiets

assumptionassumption: something toxic in wheat: something toxic in wheat analysisanalysis: nothing toxic in tissues: nothing toxic in tissues realityreality: vitamin deficiency: vitamin deficiency scientific methods for formulating feeds were scientific methods for formulating feeds were

inadequateinadequate research diets eventually simplified/purifiedresearch diets eventually simplified/purified

History of Nutrition History of Nutrition IV.IV.

First vitamin discovered in 1913First vitamin discovered in 1913 pioneer nutritional work achieved primarily pioneer nutritional work achieved primarily

through the use of animal subjectsthrough the use of animal subjects same today, but with restrictionssame today, but with restrictions rats rats vitamins, amino acids, minerals vitamins, amino acids, minerals dogs dogs insulin, nicotinic acid insulin, nicotinic acid guinea pigs guinea pigs prevention of scurvy prevention of scurvy chicks chicks thiamin and other vitamins thiamin and other vitamins bacteria bacteria growth factors, nutrient function in growth factors, nutrient function in

metabolismmetabolism final answers must be derived from speciesfinal answers must be derived from species

studiedstudied

Nutrition TodayNutrition TodayAnimal nutrition today is multidisciplinary:Animal nutrition today is multidisciplinary: metabolism: physiologists, biochemistsmetabolism: physiologists, biochemists vitamins: organic chemistsvitamins: organic chemists isotopes/chromatography: physicistsisotopes/chromatography: physicists protein structure: molecular biochemistsprotein structure: molecular biochemists breed variation: geneticistsbreed variation: geneticists vitamins/amino acids: microbiologistsvitamins/amino acids: microbiologists additives/improved digestibility: food additives/improved digestibility: food

technologiststechnologists

Issue: OverexpansionIssue: Overexpansion

Everyone now-a-days appears to be an expert in Everyone now-a-days appears to be an expert in nutritionnutrition

infomercials, algae, diet fadsinfomercials, algae, diet fads claims of superiority without scientific evidence claims of superiority without scientific evidence

(science vs. pseudoscience)(science vs. pseudoscience) example: massive doses of vitamins are useless, example: massive doses of vitamins are useless,

often toxicoften toxic nutrition industry might need to become more nutrition industry might need to become more

conservativeconservative it’s no wonder why the average consumer is it’s no wonder why the average consumer is

puzzled!!puzzled!!

Nutrient EssentialityNutrient Essentiality

essential nutrient: one that must be provided in the diet in order to insure adequate growth and maintenance, indispensable

Nutrient categories: macro and micro macronutrients: protein, lipid, carbohydrate, etc. micronutrients: trace metals, vitamins important: molecular weight is not the basis,

requirement level is proteins: g/kg vitamins: µg/kg large requirement doesn’t imply greater importance

(example: B12 in some fish 0.4 µg/day)

Basic Nutritional Basic Nutritional ConceptsConcepts

Animal nutrition is tied back to food crops and ultimately to the nutritive value of soil

strong interrelationship between human and animal nutrition

foods/feeds of both contain similar nutrients metabolic processes are basically similar nutritional niche of animals: animals

concentrate nutrients of food crops into more nutritious and palatable forms for humans

point: animals take sources unsuitable for humans and improve their quality for us!

Animals as Primary Animals as Primary ConsumersConsumers

Animals produce meat, milk, etc. on land that is often unsuitable for production of food crops

problem: overall land availability vs. protein demand

fisheries flat, agriculture barely keeping up nutrition has greatly improved production

capacity, however it is not going to be enough

What Does it All What Does it All Mean?Mean?

We already know that agriculture is barely keeping up with world food demand and...

Fisheries are being improperly managed to the point of steady state

Either we must quickly apply Iowa corn field technology to all arable land on Earth or food must be found from other sources

One possible option is aquaculture.

We already know that agriculture is barely keeping up with world food demand and...

Fisheries are being improperly managed to the point of steady state

Either we must quickly apply Iowa corn field technology to all arable land on Earth or food must be found from other sources

One possible option is aquaculture.

Current Current Challenges/ProblemsChallenges/Problems

For aquaculture to contribute more to the For aquaculture to contribute more to the world’s food supply, production must be world’s food supply, production must be intensifiedintensified

higher yields must be achieved in pondshigher yields must be achieved in ponds better and more predictable natural sources of better and more predictable natural sources of

nutrition (natural productivity) must be available nutrition (natural productivity) must be available (too unpredictable)(too unpredictable)

more crude feed materials used as supplements more crude feed materials used as supplements or or

compounded feeds must provide all nutrientscompounded feeds must provide all nutrients retention vs. digestibility: Which is best metric?retention vs. digestibility: Which is best metric?

Part 2: The Animal Body and Its Food

From: Lovell and Maynard, et al.

Learning Objectives

Aquatics, compared to terrestrials, are typically better converters of nutrients into body tissue.

This does not apply in all cases to all nutrients.

Aquatics vs. Terrestrials: feeding issues

Aquatics are what they are: submerged in water Guess what?? The water itself can serve as a

source of nutrition (natural productivity). Examples?

Overfeeding of land animals does not necessarily imply ruining of their environment

In water, nutrients are quickly “lost” if feed is not immediately consumed

Waste is not readily observable, thus, attraction and palatability of aquatic feeds is important.

Aquatics vs. Terrestrials: nutrient requirements

Overall qualitative (which nutrients) requirement is generally similar between land and aquatic animals.

Energy requirements are lower for fish than most terrestrials higher protein: energy ratio.

Marine species require some fatty acids and sterols that terrestrials don’t.

Aquatics have reduced dietary mineral requirement (environment is nutrient source)

Some fish/most crustaceans have limited ability to synthesize ascorbic acid

Shrimp cannot synthesize cholestrol.

Aquatics vs. Terrestrials: nutrient requirements

Nutrient requirements for one group of finfish or crustaceans can only serve as a starting point for other species

Lysine example.Nutrient requirements will ultimately

become more and more refinedProblem: apparent vs. true requirement

Aquatics vs. Terrestrials: Which protein is better?

fi sh convert practical f eeds into body tissue more effi ciently than do f arm animals

catfi sh f ed compounded rations gain approximately 0.84 g of weight per gram of practical diet (Lovell, 1989)

Why? they are able to assimilate diets containing higher percentages of protein

Also, they have a lower dietary energy requirement (thus, most protein goes to growth)

0

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animal type

% conversion

catfishchickencattle

Aquatics vs. Terrestrialshowever, dietary protein conversion to body protein by chickens is similar to fish

fish don't convert f ood more effi ciently, it's just that they get more out of the protein they consume

advantage: lower energy cost of protein gain, not superior f ood conversion effi ciency

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animal type

Pro gain/g Pro consumed

catfishchickencow

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40

50

animal type

Pro gain/Mkcal ME consumed

catfishchickencow

Aquatics vs. Terrestrialsproblem: the total energy budget f or production of protein f rom fish culture systems hasn't been well investigated

ponds seem to be similar to that needed for broiler chicken production

i.e., chickens need heating and ventilation, fish need water exchange/ aeration

thus, if f ossil f uel requirements f or production (largely associated with transport, processing) are similar, fish are your overall more energy-effi cient sources of protein

Fish vs. Farm Animals: nutritional value

percentage of edible lean tissue in fish is appreciably greater than that in beef , pork or poultry

however, due to low fat, the caloric value of dressed fish is

less than that of beef or pork

net protein utilization is about the same as that of red beef (83 vs 80; 100 f or eggs)

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animal type

% of dressed as lean tissue

catfishbeefporkchicken

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animal type

food energy (kcal/100 g edible tissue)

catfishbeefporkchicken

Aquatics vs. Terrestrials: nutritional value

fish, as with other animal flesh, is a good source of most nutrients

exception: calcium, vit A, vit C

one 8 oz. hamburger patty or fi llet each provides 100% of the RDA f or protein, niacin, vitamin B12 and phosphorus

at same time, though, the fish would only contain 280 calories as compared to the burger with 750 calories

Animal Classifications: we as humans are omnivorous

we eat f ood f rom both vegetable and animal sources

other omnivores: pig, rat, shrimp

herbivores are those animals that live largerly on vegetable or plant sources of nutrition

examples: ruminants (cattle, rabbits, horses), tilapia

omnivores and herbivores contribute most to the human food supply

carnivores aren't much of an influence

Composition of the Animal Body

if we are consumers of omnivores and herbivores, we are concerned with what nutrients they contain

what is the nutritional composition of the animal body?

original work on determining body composition of f arm animals of various age and nutrient status

impetus: human health and combating of disease

as a result, we now have a large amount of information on this subject

Percent Composition of the Animal Body

Species Water Protein Fat Ashcalf, new 74 19 3 4.1calf, fat 68 18 10 4.0steer, thin 64 19 12 5.1steer, fat 43 13 41 3.3pig, 8kg 73 17 6 3.4pig, 30 kg 60 13 24 2.5pig, 100 kg 49 12 36 2.6horse 61 17 17 4.5human 60 18 18 4.3mouse 66 17 13 4.5guinea pig 64 19 12 5.0

Percent Composition of Percent Composition of AquaticsAquatics

AnimalAnimal WaterWater ProteinProtein FatFat AshAsh

ChanneChannel l catfish, catfish, musclemuscle

77.3077.30 16.3016.30 5.405.40 1.101.10

Artemia Artemia naupliinauplii

89.0989.09 6.296.29 1.401.40 1.021.02

White White shrimpshrimp

90.0090.00 7.177.17 0.500.50 1.301.30

Water and Organic Substances

Table 2-1 indicates that body composition f or species varies with age and nutritional state

by nutritional state, we mean f at or thin

it can also be applied to pregnant or, in the case of crustaceans, molt status

age aff ects body composition largely by decreasing water content

this is especially true in very early age

Age vs. Water and Fat Content

embryo: 95%, shortly af ter conception

embryo: 75-80%, at birth

calf : 66-72%, at five months

mature: 40-65%

variations in water content of growing animals are largely due to the storage of f at

as animals grow, they have a tendency to store f at (depending upon f eed intake)

fat displaces water

Distribution of Protein, Lipid, COH

proteins are found in every cell of the body

besides water, they are the principle constituent of the body

organs, muscle, tendons, connective tissue

fat is localized in adipose tissue, f at depots under the skin, around the intestines/ other organs

it is also present in muscles, bones, etc.

very small amount of carbohydrates are found in liver, muscles, and blood (constantly being used for energy or re-formed)

The Blood

f rom a nutritional standpoint, the composition of the blood is very important

it is the medium by which oxygen and nutrients are transported to various tissues

it is the means whereby waste products of metabolism are removed (kidneys)

it comprises 5-10% of body weight and varies by species, body weight, nutritive state

The Blood (continued)total blood volume really varies due to the amount of active tissue a body has

as mentioned, the solid matter of blood (corpuscles) consists almost entirely of the iron-containing protein, hemoglobin

hemoglobin is used to transport oxygen

for most crustaceans, the O transport protein is hemocyanin (Cu)

some crustaceans use pinnaglobulin, which has manganese (Mn) at its center

2

Muscle and Other Tissues

movement of the body, organs and tissues require muscle action

thus, we have muscles distributed throughout the body

1/ 2 the body is composed of skeletal muscle (75% water, of the dry matter, 75-80% is protein)

the remainder of muscle tissue is largely f at, COH (glycogen), minerals

Muscle and Other Tissues (continued)

epithelial tissue (skin, hair, f eathers, lining of the various tracts) are largely composed of keratin

this type of protein is arranged diff erently f rom other proteins and is highly insoluble or digestible

connective tissue (cartilage, tendons, ligaments, bone matrix) consists primarily of insoluble collagen (protein)

nervous tissue is primarily composed of complexes of lipid, COH, protein

Estimation of Body Composition

body composition inf ormation provides inf ormation on the stage of development and nutrition of animals

you can't simply weigh the animal to determine this

animals must be slaughtered and analyzed chemically, usually combined with f eeding experiments

unfortunately the animal can be used only once, changes can't be determined

For Next Time…For Next Time… Quiz 2: Environmental Factors Quiz 2: Environmental Factors Topic 3: Digestive Physiology, Nutrient Topic 3: Digestive Physiology, Nutrient

Digestability (What happens to the food fish Digestability (What happens to the food fish eat?)eat?)

Handouts, Lovell (1989).Handouts, Lovell (1989).