Masters Theses

Date of Award

6-1977

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Science

Major Professor

Karl M. Barth

Committee Members

J.B. Jones, Eric W. Swanson, James B. McLaren

Abstract

A six-month experiment was conducted to study the reproductive response of 42 nu/+ female mice and 21 nu/nu thymus transplanted male mice of BALB/c background to three dietary protein levels. The mice were housed as breeding trios (one male and two females), and seven trios each were assigned to one of three rations—12, 18, or 24% crude protein. Data were collected on reproductive performance, weight of pups, hematological parameters and organ weights. Analysis of variance showed no significant differences among females with respect to reproductive performance. No significant differences were found in hematological parameters or organ weights when expressed as a percentage of bodyweight except among the nu/nu transplanted males, where the 24% protein males had significantly higher (P<.10) spleen weights. The pup weights showed no differences at birth but at weeks 1, 2, and 3 the 18 and 24% pup weights were higher (P<. 05) than the 12% pup weights. Gain for weeks 1 and 2 and total gain were significantly higher in the 18 and 24% pups, while gain for week 3 was significantly (P<.025) higher in the 12% pups.

Three rations differing in crude protein levels, 12, 18, and 24%, were fed to 128 nude females, 103 nude males, 126 nu/+ females and 102 nu/+ males for one month (28 days) from 21 days of age (weaning) to 49 days of age. The weanling mice were maintained on the same level of dietary crude protein that had been fed to their parents. The mice were weighed every four days and food consumption was calculated for four-day periods. At the end of 28 days, the mice were sacrificed, their organs weighed, and serum protein levels recorded.

The nu/+ female mice grew best on the 24% protein ration, while the nu/+ male mice grew best on the 18% protein ration. The nude mice, many of which succumbed to wasting disease (thought to be mouse hepatitis virus), gained best on the 12% ration (females) and on the 18% ration (males). These figures were obtained from averages which included those mice which ceased to grow, lost weight and became moribund. When these mice were removed from the data, the nude females grew best on 24% protein while the nude males still grew best on the 18% protein. The incidence of wasting disease, death, and necrotic liver lesions was lowest in the 12% protein nude females (5.6%). Twelve percent nude males had the next lowest incidence (23.8%) followed by 18% nude males (38.1%), 24% nude females (41.0%), 18% nude females (48.1%) and 24% nude males (51.2%).

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