L. B. Carew

Dietary Carbohydrate and Fat Do Not Alter the Thyroid Response to Protein Deficiency in Chicks

Abstract Consumption of low-protein diets consistently causes elevations in circulating levels of triiodothyronine (T3) in several species of animals. In chicks this is often accompanied by lower levels of circulating thyroxine (T4). Since low-protein diets are usually formulated by replacing the deleted protein with carbohydrate, the question arises as to whether the changes in thyroid hormones are a result of the lower protein or higher amounts of carbohydrate in such diets. Male broiler chicks, 13-26 days of age, were fed experimental diets that contained either an adequate level of protein (24%) or levels that were slightly (17%) or moderately (10%) deficient in protein. The deleted protein was replaced, isocalorically, with either glucose, soybean oil, or hydrogenated coconut fat. Though the level of protein and source of energy differed among diets, all diets contained identical amounts of all nutrients and energy, and were of similar weight densities. Circulating levels of thyroid hormones were measured from blood samples taken at the end of the study. Plasma T3 was elevated to a similar degree in all protein-deficient animals compared with control. Plasma TV4 decreased in all protein-deficient chicks and was lowest with 10% dietary protein. Changes in circulating levels of thyroid hormones occurred independently of the source of dietary energy. Therefore, it is concluded that alterations in circulating levels of thyroid hormones that occur in chicks fed low-protein diets are a specific effect of the protein deficit and are not a related to the amounts of carbohydrate or fat present in the diet.

Evaluation of a Computer-Assisted Instructional Component in a College-Level Nutrition Course

Abstract The effectiveness of computer-assisted instruction (CAI) in nutrition education was evaluated by determining if a CAI program designed to reinforce class lectures and available on disks and the university network was associated with higher cognitive achievement test scores. Students’ opinions concerning the helpfulness, advantages, and disadvantages of such a program were also assessed. Our CAI program was available to 243 students in four sections of an introductory nutrition course. Students could use the CAI program for any amount of time. There were 160 users and 83 nonusers. A valid and reliable cognitive pretest–post-test, an attitude assessment, and a demographic and opinion questionnaire were used. Differences in pretest–post-test scores were analyzed by two-way analysis of variance. Internal consistency of the attitude assessment instrument was determined using Cronbachs alpha test. Users of the CAI program had higher pretest–post-test gain scores than nonusers. Eighty-seven percent of the students thought that the program was useful or very useful; 78% thought that it improved their grades. Students’ attitudes were positive toward use of computers and, generally, improved with use of the program. We concluded that class material in a computerized format available on disks and a network is useful for improving performance of students in a college-level, introductory nutrition course.

Surgical Removal of the Pineal Gland in 3—5-Day-Old Chicks

Summary A quick, reliable procedure for the surgical removal of the pineal gland from 3 to 5-day-old chicks is presented. This procedure for pinealectomy was satisfactory as judged by low mortality and high success of the operation as verified at autopsy. The entire procedure requires approximately 5 min/chick. Nembutal, Equi-Thesin, and ether were evaluated as anesthetic agents for use in pinealectomy. Ether was the most suitable drug because of its ease of administration, rapid induction, short recovery period, and low mortality experienced with its use.