560 likes | 947 Views
Biomethodology Of The Rat. Office of Laboratory Animal Care University of Tennessee, Knoxville. General Behavior. Nocturnal Photoperiod 12:12 or 14:10 for breeding colonies Non-aggressive, inquisitive, trainable Coprophagic Accept single housing
E N D
Biomethodology Of The Rat Office of Laboratory Animal Care University of Tennessee, Knoxville
General Behavior • Nocturnal • Photoperiod 12:12 or 14:10 for breeding colonies • Non-aggressive, inquisitive, trainable • Coprophagic • Accept single housing • Males unlikely to fight when housed together
Body Weight Gain Chart CD Rat
Reproduction • Estrus Cycle 4–5 d • Gestation 21–23 d • Litter size 3-18 pups • Haircoat 8-9 d • Eyes open 10-14 d • Weaning 21 d • Postpartum estrus
Sexing • Anogenital distance is longer in the male and shorter in the female Male Female Genital Opening Anus
Housing • Adequate housing should provide the following: • Behavior and physiological needs • Social interaction • Clean, dry and safe area with adequate ventilation, food and water • Visualization by personnel • Sufficient space to turn around and make normal postural movements
Housing Recommendations • Primary enclosure space recommendations per the Guide for the Care and Use of Laboratory Animals
Primary Enclosure • Enclosure • Easy visualization • Solid bottom flooring • Bedding and enrichment • Locking wire bar lid • Water bottle • Feed • Microisolator top • Reduces spread of pathogens
Environmental Conditions • Temperature 68 – 79⁰F • Humidity 30 -70% • Ventilation 10 -15 air changes/hr. • Light levels 130 -325 lux • Noises sustaining ≥85 db can cause • Stress • Metabolic changes • Reduced fertility Room Recommendations
Identification • Hair Clipping • Temporary • Markers and Dyes • Ear Tags • Permanent • Ear Punches • Tattoos • Microchip
Identification • Cage Card
Manual Restraint • Use gloves • Grasp the tail 1-2 cm from the base and place rat on wire bar lid
Manual Restraint • Palm the rat over the back • Push the rat against the wire bar • Advance hand toward rat’s head
Manual Restraint • Place index and middle finger around the neck • Keep the head between the middle and index fingers
Manual Restraint • The thumb and second finger should be placed under opposite axilla • The tail can be held by the opposite hand
Manual Restraint • Click to Watch Video
Mechanical Restraint Plastic adjustable restrainers • Decapicones
Blood Collection • Survival Procedures • Tail vein • Orbital plexus • Non-Survival Procedures • Cardiac puncture • Axillary cut down • Cranial vena cava puncture
Blood Collection • Blood Collection Guidelines • Single blood draw • ≤1.0 ml per 100 grams of body weight • Multiple blood draws • Maximum of 1.5 ml per 100 grams of body weight within a 2 week period
Blood Collection • Tail Vein • Use for collecting 0.1–2.0 ml of blood • Heat source to dilate blood vessel • Proper restraint • ≤ 21 gauge needle
Blood Collection • Click to Watch Video
Blood Collection • Orbital plexus • Use for collecting up to 4 ml of blood • Anesthetize rat • Hold the head steady • Insert pipette in the medial canthus of the eye • Rotate the tube between thumb and finger • Keeping eyelids closed, apply direct pressure using gauze for hemostasis
Blood Collection • Click to Watch Video
Blood Collection • Cardiac • Use for collecting up to 15 ml of blood • Anesthetize rat • ≤21 gauge needle • Insert needle under sternum at a 20⁰ angle • Aspirate slowly • Euthanize rat
Blood Collection • Click to Watch Video
Tissue Collection • Tail Biopsy • Limited to a maximum of 2 times • Maximum biopsy size of 5 mm • Analgesia/Anesthesia is required for rats 21 days of age and older and in rats weighing 50 grams or more
Compound Administration • 21 to 25 gauge needle Maximum Administration Volumes (in ml/kg)
Compound Administration • Subcutaneous (SC or SQ) • Locate site of injection • Insert needle underneath skin • Aspirate negative pressure • Inject compound and watch for SQ bleb • Pause before retracting needle
Compound Administration • Intraperitoneal (IP) • Assistance is helpful • Locate lower right quadrant for injection site • Aspirate • If an unintended subcutaneous bleb occurs, reposition the needle
Compound Administration • Intravenous (IV) • Lateral tail vein • Proper restraint • Heat source to dilate blood vessel • After removing needle, apply direct pressure for hemostasis
Compound Administration • Gastric Gavage (PO) • Use a bulb-tipped gastric gavage needle • Measure length of needle from mouth to last rib • DO NOT FORCE the needle down the esophagus • Inject solution • Observe rat for signs of distress
Anesthesia • When planning any procedure involving anesthesia and/or surgery, please consult one of the Laboratory Animal Veterinarians in the Office of Laboratory Animal Care (OLAC) at 974-5634. • The Veterinarian can provide guidance and detailed information in selecting the most appropriate anesthetic and analgesic protocol for your rat and procedure.
Aseptic Technique • Surgical Prep • After induction of anesthesia, clip hair from the surgical site • Prep skin with povidone iodine, chlorhexidine or other appropriate skin antiseptic • Scrub in a circular pattern, beginning in the center and spiraling outward • Follow povidone iodine scrub with a 70% alcohol prep • Repeat Twice • End procedure with a light coat of povidone iodine solution (not scrub) to the surgical site
Aseptic Technique • Place a sterile drape over the rat • Anything that touches the surgical site must be sterile • Non-absorbable sutures/clips should be removed in 7-14 days
Surgical Monitoring • Prevent pain, hypoxia, and hypothermia • Monitor withdrawal reflex • Provide a source of external heat • Provide appropriate analgesics for post-operative pain management
Euthanasia • Inhalant Anesthetic Overdose • Isoflurane • End the procedure with a thoracotomy or cervical dislocation • Carbon Dioxide • Place rat in the chamber • Turn on CO2 flow into the chamber • Once the rat has stopped breathing, wait at least 1 minute before removing the rat from the chamber • End the procedure with a thoracotomy or cervical dislocation • Substantially prolonged in neonates • Cervical Dislocation • Performed on anesthetized rats weighing <200 grams • Must be performed by skilled personnel
Prevention of Infectious Disease • Colony Health Surveillance • Sentinel rats are tested on a routine basis • Gross necropsy • Serological assays • Tests for parasites • Rat Antibody Production Test (RAP Test) and PCR • A test for cell lines and tumors for rodent viruses • Included in every animal use protocol
Occupational Health and Safety • PPE (Personal Protective Equipment) • Protects handler and rat • May include: gloves, shoe covers, gowns, lab coats, masks, and head covers • Zoonoses prevention • Proper handling • Health surveillance programs • Routine sanitation • Proper use of PPE
Health Surveillance Rat Serology (RADIL) • Rat coronavirus (RCV) • Generic parvovirus (NS1) • Rat parvovirus (RPV) • Rat minute virus (RMV) • Kilham rat virus (KRV) • Toolan's H-1 (H-1) • Rat theilovirus (RTV) • Sendai virus • Pneumonia virus of mice (PVM) • Mycoplasmapulmonis • Reovirus 3 • Lymphocytic choriomeningitis virus (LCMV) • Cilia associated respiratory bacillus (CARB) • Hantaan virus • Tyzzer’s • Mouse adenovirus (MAD1)
Procurement of Rats • APPROVED vendors include Charles River, Jackson Labs, Harlan, NCI-Frederick, and Taconic • Rats that are shipped from a non-approved vendor source must be approved by OLAC before the rats are procured. • An animal requisition form must be submitted to the facility manager: http://www.vet.utk.edu/olac/pdf/animal_acquisition_form.pdf
Quarantine • Quarantine is required if receiving rats from an unapproved vendor • The minimum quarantine period is six (6) weeks • No experimental manipulations or breeding can be initiated during the quarantine period unless approval has been granted by an OLAC veterinarian
Health Concerns • Whenever possible, pain and distress should be eliminated • General appearance • Lethargy • Aggressiveness • Hunched posture
Health Concerns • Eyes • Porphyrin staining = Stress • Teeth • Overgrowth • Tooth breakage • Malocclusion
Health Concerns • Body Condition • Swellings or Tumors • Poor Haircoat • Ectoparasites • Stress • Cold • Poor Nutrition
Body Condition Scoring Hickman DL, Swan M 2010
Reporting Signs of Pain or Distress • For Rats That Require Veterinary Care • Complete the red “Sick Animal” cage card • Attach card to cage • Notify facility manager or • Print Clinical Case Request Form http://www.vet.utk.edu/olac/pdf/CLINICAL_CASE_REQUEST.pdf • Fax form to the OLAC office 974-5649 • Assessment of the animal’s condition and treatments will be recorded on the “Sick Animal” card
References • Guide for Care and Use of Laboratory Animals. National Academy Press, 2011. • Hickman, DL, Melissa Swan. 2010. Use of Body Condition Score Technique to Assess Health Status in a Rat Model of Polycystic Kidney Disease. J Am Assoc Lab AnimSci 49:155-159. • Lawson, PT. Assistant Laboratory Animal Technician (ALAT) Training Manual. The American Association for Laboratory Animal Science, Memphis, TN. 2005. • Sharp, Patrick and Marie LaRegina. The Laboratory Rat. CRC Press, Boca Raton, FL. 1988. • Presentation: Chris Carter, OLAC UTK