RICHARD W. LUECKE ANDPAMELA J. FRAKER Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824 ABSTRACT The objectives of the present study were to determine the zinc requirement of two strains of young growing female mice. The strains tested were outbred Swiss mice and inbred A/J mice. In addition to using growth as a criteria of zinc adequacy, the response to immunization with sheep red blood cells (SRBC) was measured in each strain at various dietary zinc levels. The dietary levels of zinc fed in a biotin-fortified egg white diet were: 0.7, 3.3, 5.9, 8.2, 11.0 and 31.4 mg/kg. It was found during a 3-week experimental period that the outbred Swiss mice attained maxi mum growth and normal antibody-mediated response at a zinc level in the diet of 5.9 mg/kg. The inbred A/J mice in a 2-week experimental period were also able to attain maximum growth and normal antibody-mediated response at 5.9 mg Zn/kg. It is concluded that there were no differences in the zinc requirement for growth of the two strains of mice used and also that the zinc requirement for immunological competency as measured by the Jeme plaque assay using SRBC antigen were similar. The results indi cate that the mouse has a lower dietary requirement for zinc than the rat. J. Nutr. 109: 1373-1376, 1979. INDEXING KEY WORDS zinc requirement •immunity •mouse Although the mouse has been widely used as an experimental model, very little attention has been devoted to research on nutrient requirements of this species. It is frequently assumed that mouse requirements are similar to those of the rat. The zinc requirement of the growing rat has been found to approximate 12 mg/kg of diet (1, 2). Palluf and Kirchgessner (3) have found the minimum zinc requirement for growth to be 8 mg/kg of diet, but 12 mg Zn/kg diet was necessary for optimum zinc contents in serum and liver. In all of these studies, either casein or egg white served as the protein source. Although the zinc requirement of the rat for growth has been reasonably well established, we are not aware of a similar situation with reSpect ~
to the
14\ (t)
requirement
mouse.
The
National
Research
Hrw»« QOeS nnt not list USI aa minimum minimum
7\nr Zinc
tor this species. In an early
study of zinc deficiency in the young mouse, Day and Skidmore (5) reported that the feeding of a diet containing only 0.3 mg Zn/kg resulted in deficiency signs which included growth impairment and loss of hair; in general, the signs described were similar to those commonly observed in the zinc deficient rat. Accordingly, in view of our interest in the effects of zinc deficiency on the immune response of mice (6, 7), we considered it desirable to determine if the zinc requirement of this species for zinc was similar to that of the rat. Moreover, we wished to determine whether a dietary zinc level which was adequate for growth would also produce a _ Recelyedfor publlcatlonOctober10 1978 , supported
in part by the National
Institute
of
Health. Grant No. HD-10586 the Michigan cultural Experlment Station and as Journal Article AgrlNo.
3744. 1373
Downloaded from https://academic.oup.com/jn/article-abstract/109/8/1373/4770762 by East Carolina University Health Sciences Library user on 15 January 2019
The Effect of Varying Dietary Zinc Levels on Growth and Antibody-Mediated Response in Two Strains of Mice1
RICHARD W. LUECKE AND PAMELA J. FRAKER
1374
TABLE l
g/kg Glucose monohydrate Egg white solids (spray-dried)1 Corn oil Fiber1 Salt mix1 Vitamin mix1 Ethoxyquin4
590 220 100 30 40 10 10
1Cellulose-type fiber. Teklad Test Diets, Madi son. Wisconsin. *Bernhart, F. W. & Tommarelli, R. M. (1966) J.Nutr. 89,495, except that a U.S.P. grade of CaHPO«was used instead of reagent grade, and also zinc carbonate was omitted. *Composi tion similar to the AIN-76 mixture (1977) J.Nutr. 107, 1340,except that the biotin level was increased to provide an additional 4 mg/kg diet. *Santoquin, Monsanto Chemical Co., St. Louis, Missouri.
normal response to immunization with SRBC as previously observed (7). In our previously reported studies, young adult A/J female inbred mice 2 were used; how ever, since Reis and Evans (8) reported a relationship in the mouse between heredi tary background and nutritional zinc re quirement, the possibility existed that the requirement for zinc of the inbred A/J mouse was atypical of the species in gen eral. The objectives of the present study, therefore, were to compare the growth re sponse to varying levels of zinc of two strains of 21-day old female mice and, in addition, to measure the antibody-medi ated response of these two strains of mice to immunization with sheep red blood cells (SRBC).
METHODS Animals and diets. The two strains of 21-day old female mice used were an outbred strain of Swiss mice 3 and the inbred A/J mice.2 At the time of receipt, both groups of mice were placed in polycarbo nate mouse boxes, bedded with wood shavvings, and fed a commercial stock diet * for a period of 2 days. For the experimental period the mice were housed in hanging cages of stainless steel wire with free access to deionized water and were fed ad lib itum. Each of the six dietary treatment groups consisted of 12 mice with four ani mals housed per cage. Diet consumption was monitored daily; weight gain was de termined on the seventh day and every 3 days thereafter. The zinc-deficient diet used represented a modification of the one previously reported (9) and is shown in table 1. The principal modifications con sisted of an increase in the amount of egg white solids used, a change in the salt mix ture, and the use of an antioxidant in addi tion to a-tocopherol at a level of 50 mg/kg. A total of six diets were used, five of which contained supplementary zinc as zinc carbonate. All of the diets were as sayed in duplicate for zinc by atomic ab sorption spectrophotometry,5 and the sam ples were prepared for analysis by wet ash ing in a nitric-perchloric acid mixture ( 10). The results of the zinc analyses of the six - Jackson Laboratory, Bar Harbor, Maine. 3 Spartan Research Animals, Inc., Haslett, Michi gan. « Mouse Breeder Blox, Allied Mills, Inc., Chicago, Illinois. 5 VarÃ-anTectron Model 175, Sunnyvale, California.
TABLE 2 Experiment 1. The effect of dietary zinc level on growth, diet consumption, and certain immunological parameters of outbred Swiss mice for the 14 and HI days1 Dietary zinc (in mg/kg) 0.7
g21-day 14-day wt, gTotal wt, gJeme diet consumed, assay1(per plaque spleen)IgM (direct)IgG (indirect)11.5
±0.3«10.9 ±0.2«34.3 ±3.5«11,100
3.3
±0.6»17.3 ±0.7»51.1 ±1.3»69.000
5.0
8.2
11.0
31.4
±1.2«24.4±1.0
to the
14\ (t)
requirement
mouse.
The
National
Research
Hrw»« QOeS nnt not list USI aa minimum minimum
7\nr Zinc
tor this species. In an early
study of zinc deficiency in the young mouse, Day and Skidmore (5) reported that the feeding of a diet containing only 0.3 mg Zn/kg resulted in deficiency signs which included growth impairment and loss of hair; in general, the signs described were similar to those commonly observed in the zinc deficient rat. Accordingly, in view of our interest in the effects of zinc deficiency on the immune response of mice (6, 7), we considered it desirable to determine if the zinc requirement of this species for zinc was similar to that of the rat. Moreover, we wished to determine whether a dietary zinc level which was adequate for growth would also produce a _ Recelyedfor publlcatlonOctober10 1978 , supported
in part by the National
Institute
of
Health. Grant No. HD-10586 the Michigan cultural Experlment Station and as Journal Article AgrlNo.
3744. 1373
Downloaded from https://academic.oup.com/jn/article-abstract/109/8/1373/4770762 by East Carolina University Health Sciences Library user on 15 January 2019
The Effect of Varying Dietary Zinc Levels on Growth and Antibody-Mediated Response in Two Strains of Mice1
RICHARD W. LUECKE AND PAMELA J. FRAKER
1374
TABLE l
g/kg Glucose monohydrate Egg white solids (spray-dried)1 Corn oil Fiber1 Salt mix1 Vitamin mix1 Ethoxyquin4
590 220 100 30 40 10 10
1Cellulose-type fiber. Teklad Test Diets, Madi son. Wisconsin. *Bernhart, F. W. & Tommarelli, R. M. (1966) J.Nutr. 89,495, except that a U.S.P. grade of CaHPO«was used instead of reagent grade, and also zinc carbonate was omitted. *Composi tion similar to the AIN-76 mixture (1977) J.Nutr. 107, 1340,except that the biotin level was increased to provide an additional 4 mg/kg diet. *Santoquin, Monsanto Chemical Co., St. Louis, Missouri.
normal response to immunization with SRBC as previously observed (7). In our previously reported studies, young adult A/J female inbred mice 2 were used; how ever, since Reis and Evans (8) reported a relationship in the mouse between heredi tary background and nutritional zinc re quirement, the possibility existed that the requirement for zinc of the inbred A/J mouse was atypical of the species in gen eral. The objectives of the present study, therefore, were to compare the growth re sponse to varying levels of zinc of two strains of 21-day old female mice and, in addition, to measure the antibody-medi ated response of these two strains of mice to immunization with sheep red blood cells (SRBC).
METHODS Animals and diets. The two strains of 21-day old female mice used were an outbred strain of Swiss mice 3 and the inbred A/J mice.2 At the time of receipt, both groups of mice were placed in polycarbo nate mouse boxes, bedded with wood shavvings, and fed a commercial stock diet * for a period of 2 days. For the experimental period the mice were housed in hanging cages of stainless steel wire with free access to deionized water and were fed ad lib itum. Each of the six dietary treatment groups consisted of 12 mice with four ani mals housed per cage. Diet consumption was monitored daily; weight gain was de termined on the seventh day and every 3 days thereafter. The zinc-deficient diet used represented a modification of the one previously reported (9) and is shown in table 1. The principal modifications con sisted of an increase in the amount of egg white solids used, a change in the salt mix ture, and the use of an antioxidant in addi tion to a-tocopherol at a level of 50 mg/kg. A total of six diets were used, five of which contained supplementary zinc as zinc carbonate. All of the diets were as sayed in duplicate for zinc by atomic ab sorption spectrophotometry,5 and the sam ples were prepared for analysis by wet ash ing in a nitric-perchloric acid mixture ( 10). The results of the zinc analyses of the six - Jackson Laboratory, Bar Harbor, Maine. 3 Spartan Research Animals, Inc., Haslett, Michi gan. « Mouse Breeder Blox, Allied Mills, Inc., Chicago, Illinois. 5 VarÃ-anTectron Model 175, Sunnyvale, California.
TABLE 2 Experiment 1. The effect of dietary zinc level on growth, diet consumption, and certain immunological parameters of outbred Swiss mice for the 14 and HI days1 Dietary zinc (in mg/kg) 0.7
g21-day 14-day wt, gTotal wt, gJeme diet consumed, assay1(per plaque spleen)IgM (direct)IgG (indirect)11.5
±0.3«10.9 ±0.2«34.3 ±3.5«11,100
3.3
±0.6»17.3 ±0.7»51.1 ±1.3»69.000
5.0
8.2
11.0
31.4
±1.2«24.4±1.0
