Number of Words: 470
Sprague Dawley Rat
The general model for the study of human health in detecting disease is the Sparague Dawley rat. Such breed of the rodent family serves as a superb model for toxicology, reproduction and pharmacology as well as behavioral research areas.
Anatomy of Sprague Dawley rat
An adult body has a mass of 250 to 300 grams in females. For the males, they weigh about 450 to 520 grams. Both genders only last for about 2.5 to 3.5 years with a respiratory rate of 70-115 breaths per minute and heart rate of 250-450 beats per minute.
The dental formulae has a ratio of 2 is to 16. Their incisors are open- rooted and develop constantly. If ever they are mishandled, they will bite or pinch with their sharp teeth. Their esophagus enters the belly at the lesser curvature through a fold tissue. This is because of physiological structure, the Sprague Dawley rat is unable to vomit.
Similar to a horse, it does not have a gall bladder. The left lung is comprised of only a single lobe while the right has four. It has about five mammary glands. Distribution of tissue is diffuse which extends from the ventral midline over the flanks and thorax together with other portions of the neck.
Its deep gland of the nictitating membrane is a pigmented lacriminal gland that is located behind the eyeball which encircles the optic nerve. The secretion is rich in lipid and porphyrim. However, many possess a Hardenian gland where it assumes of the importance it has. During times of stress and even other sicknesses it will feel, its tears will brim and smear the face around the eyes and nose. When it is already dry, the pigment appears like a dried blood. It fluoresces under ultraviolet light and contains little or no blood at all.
Nutrition of Sprague Dawley rat
It should be fed by a commercial rodent diet and water ad lib. The food is nutritionally complete which no longer need any kind of supplementation for essential vitamins and minerals.
Its food intake is approximately 5 to 100 grams per day while water intake is about 10 to 12 milliliter per day.
Reproduction of Sprague Dawley rat
It will take about 65 to 100 days of age for breeding of both females and males. However, it is only after 35 days that the females have their first uterus. It is of polyestrous family so it ovulation is spontaneous and multiplies all year round. The span of the estrous cycle is between 4-5 days and lasts for 12 hours that appears in the evening.
Twenty- two days is the average gestation period. A fertile postpartum estrus appears within 48 hours of parturition where there is simultaneous lactation that prolongs for about 3 to 5 days due to delayed implantation.