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Fish Digestion and Feeding
Next Generation Science / Common Core Standards Addressed • HS‐LS 2‐ 6. Evaluate the claims, evidence, and reasoning that the complex interactions in eco systems maintain relatively consistent numbers and types of organisms in stable conditions, but changing conditions may result in a new ecosystem. • HS‐LS 4‐ 5. Evaluate the evidence supporting claims that changes in environmental conditions may result in: (1) increases in the number of individuals of some species, (2) the emergence of new species over time, and (3) the extinction of other species. [Clarification Statement: Emphasis is on determining cause and effect relationships for how changes to the environment such as deforestation, fishing, application of fertilizers, drought, flood, and the rate of change of the environment affect distribution or disappearance of traits in species.
Agriculture, Food, and Natural Resource Standards Addressed • AS. 03. 02 Analyze feed rations and assess if they meet the nutritional needs of animals. – AS. 03. 02. 01. c. Select appropriate feedstuffs for animals based on a variety of factors (e. g. , economics, digestive system and nutritional needs, etc. ).
Bell Work / Objectives • Describe the fish digestive system. • Describe the common methods of feeding fish. • Explain how to interpret a feed label.
Terms • Anus • Auger feeding system • Automated feeding systems • Blowers • Branchiospines • Carnivores • • Demand feeders Esophagus Hand feeding Intestines Mouth Prepared feed Stomach
Identifying Fish Digestion and Feeding • Make a list of what you have eaten in the last 24 hours. • Where did you eat those foods at? • How was the food served? • How is the body able to digest and utilize the food you consumed?
What are the parts of the fish digestive system? • The fish digestive system is somewhat similar to other animals. • Size and shape of each component of the system will vary with the type of fish and its diet. • Carnivores – Fish that eats meat. – Have a large stomach and short intestines.
What are the parts of the fish digestive system? • Parts include: – Mouth • Teeth • Tongue • Branchiospines – Esophagus – Stomach – Intestines – Anus
What are the parts of the fish digestive system? • Mouth – Entry point of system. • Carnivores mouth – Have many teeth that point inwards. – Not used for chewing. – Used to capture and hold prey. • Other fish – Few or no teeth.
What are the parts of the fish digestive system? • Tongue – Helps move food around in the mouth. • Branchiospines – Act as filters to capture small food from water as the fish swims. – Part of the gill structure that helps fish swim. • Esophagus – Short tube that connects mouth to stomach.
What are the parts of the fish digestive system? • Stomach – Organ where digestion begins. – Some stomachs will expand greatly. • Allows them to eat large quantities of food. – Other stomachs are small that will accommodate only small amounts of food. – Some fish have almost no stomach. • Esophagus connects directly to intestines.
What are the parts of the fish digestive system? • Intestines – Site of food digestion and nutrient absorption. • Anus – Exterior opening of system. – Unused food and wasted material is exited.
What are some common methods of feeding fish? • Feeding fish is very important. – Provide the appropriate nutrition. – Observe fish for any abnormal signs. • Feeding systems differ based on size of the operation. – Small operations – Large operations
What are some common methods of feeding fish? • Small Operations – Hand feeding • Feed is distributed by hand, shovels, or other non-automated means. • Most common method. • Used for feeds not suited for automated systems. • Meat scraps are hand fed.
What are some common methods of feeding fish? • Large Operations – Automated feeding systems • Utilize machinery to distribute the feed. • From relatively simple to very complicated, computer-controlled. • Blowers • Demand feeders • Auger feeding systems
What are some common methods of feeding fish? • Blowers – Drive along the side of the pond and blow feed out into the pond. – Attached to trucks or tractors. – Common in levee pond and watershed pond operations.
What are some common methods of feeding fish? • Demand feeders – Allow fish to bump a rod and release feed when they are hungry. – Used in raceways. – Fish must be trained how to use them.
What are some common methods of feeding fish? • Auger feeding – Similar to systems used by swine and poultry farmers. – Feed stored in large tanks – Moved by augers that drop feed in pond – Common in tanks and raceways
What does a feed label tells us? • Fish farming utilizes prepared feeds. – A feed that is produced by a feed mill and then sold in bags or bulk. – Required to have a label approved by the state department of agriculture.
What does a feed label tells us? • • • Net weight Product name Brand name Guaranteed analysis Drug additives
What must the guaranteed analysis section contain? • Minimum % of crude protein • Maximum & minimum % of protein from nonprotein nitrogen • Minimum % of crude fat • Maximum % of crude fiber • Minimum and maximum % of salt and calcium • Minimum % of phosphorus • Other minerals • Vitamin content
What must be included on label if feed has drugs in it? • The word “medicated” • Purpose of medication must be stated. • Directions and precautions for medication. • Listing of all active drug ingredients.
Review / Summary • What are the parts of the fish digestive system? • What are some common methods of feeding fish? • What does a fish label tell us?