Maternal Food Restriction: Effects on Offspring Behavior and Development

DONALD R. OTTINGER GILFRED TANABE

Department of Psychology Purdue Universit y Lafayette, Indiana

OTTINGER, DONALD R., and TANABE, GILFRED (1968). Maternal Food Restriction: Effects on Offspring Behavior and Development. DEVELOPMENTAL PSYCHOBIOLOGY, 2( 1): 7-9. Pregnant rats were placed on reduced food intake or remained on adequate diet during gestation and lactation. Offspring were cross-fostered to provide for inde- pendent experiences of prenatal and/or postnatal mother malnutrition. All offspring were placed on an ad lib diet at time of weaning. When evaluated in adulthood, offspring whose mother was food-deprived during the lactation period showed body weight deficits and increased errors on the Hebb-Williams maze as compared to controls. There were no observed effects of the prenatal deprivation.

early experience nutrition intelligence maternal nutrition

THE EFFECT OF INFANT nutritional deficiency on later physical development has received considerable at-

tention in the nutrition literature (Chow & Lee, 1964), but its effects on behavioral development have received only minimal attention (Barnes, 1967). In one study that was concerned with behavioral development, Barnes, Cunnold, Zimmerman, Simmons, MacLeod, and Krook (1966) manipulated offspring nutrition by increasing the number of pups per litter during lacta- tion and also by raising some of these pups on a low protein diet postweaning. The group receiving pre- weaning deprivation and a low protein diet after weaning had increased error scores on a visual dis- crimination task in a water Y maze. Cowley and Griesel (1963, 1964) reared females on a low protein diet prior to mating and throughout gestation and lactation of their offspring. After weaning, these off- spring were reared on a low protein diet. The experi- mental offspring were more emotional and made more errors in the Hebb-Williams maze than non-deprived controls.

Both of these experiments demonstrated that pro- longed early nutritional deficiency resulted in reduced performance in a learning task. However, it is not possible to determine from these data which stages of development (i.e., prenatal, postnatal, or postweaning) are most critical in producing this phenomenon. The

Received for publication 28 February 1969.

Developmental Psychobiology, Z(1): 7-9 (1968)

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present report is the first study in a programmatic investigation designed to isolate the periods of develop- ment during which nutritional deficiencies have their most profound effect on later intellectual and physical development.

The purpose of the present experiment was to deter- mine if a quantitative dietary restriction of the mother during gestation and/or lactation would differentially affect later problem-solving behavior and body weight in the offspring.

METHOD

SUBJECTS AND DIET

Preliminary research established mean daily ad lib food consumption for adult females during each day of gestation and lactation. Thirty-six Purdue Wistar female rats were bred at approximately 100 days of age and subsequently produced the 14 litters used in the experiment. Following 4 days of breeding, 16 females were retained on an ad lib diet in meal form and 20 were given 50y0 of the established ad lib diet, also in meal form. Wayne Lab-Blox was used as feed for all animals and was contained in glass feeding dishes placed within the cages. Water was available ad lib at all times. Later, obviously pregnant females from both groups were transferred to maternity cages containing a tray bottom partially filled with wood

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8 OTTINGER AND TANABE

shavings. Cages were checked each morning for new pups, and the birth date of the litter was recorded as the previous day unless it was apparent that the litter had been born quite recently.

All litters were randomly reduced to 8 pups at birth, weighed, and litters cross-fostered both within and between the 2 prenatal groups. For example, litters from mothers restricted during gestation were given to other restricted mothers or to mothers fed ad lib during gestation. Once a litter had been cross-fostered, the shavings in the cage were not changed.

During lactation, mothers remained on the same diet they had received during gestation: ad lib or 50% of an ad lib diet. Thus, 4 groups of offspring were generated: ( I ) pups whose mothers were on the 507' diet during gestation and lactation, (2) gestation only, (3) lactation only, and ( 4 ) control pups whose mothers were fed nd Eib throughout the experiment. All sub- jects were weaned, weighed, sexed, and ear punched at 21 days, placed on an ad lib diet, and reared there- after in small group cages with like-sexed littermates.

PROCEDURE

Sixty subjects were randomly selected for open-field testing and body weight, and 32 offspring were tested in the Hebb-Williams maze. The open-field behavior was used as a measure of emotionality (Denenberg, in press) and the Hebb-Williams maze was used to mea- sure intelligence (Rabinovitch & Rosvold, 1951).

Animals were weighed at weaning, 40, and 61 days of age. At 49 days of age, subjects were tested in the open field, The field consisted of a 45-in. square ply- wood base with walls 18 in. high. The complete unit was painted flat black except for white lines that di- vided the floor into 9-in. squares. Subjects were placed directly into one corner of the field and allowed to remain for 3 min during which time the number of squares entered with all 4 feet and number of boluses deposited were recorded. The subjects were tested individually once per day from days 49 to 52.

At 99 days of age, 16 rats (2 females and 2 males from each group) were tested using the Hebb-Williams maze, and similar testing was performed on the re- maining 16 males and females at 130 days of age. The subject's score was the total number of errors made on the sequence of 12 test problems. The age difference was not significant and the data for all subjects were pooled for analysis.

RESULTS

Preliminary tests for litter effect indicated that litter was not a source of variation on any of the measures except body weight. Thus, the data on ac-

tivity, defecation, and Hebb-Williams maze perform- ance were classified as a 2 x 2 x 2 factorial (prenatal treatment, postnatal treatment, and sex), and an analysis of variance was computed for each of these variables using subject as the experimental unit of analysis. The data on body weight were classified by pre- and postnatal conditions, sex, and age, and an analysis of variance was computed using the litter as the unit of analysis.

BODY WEIGHT

The birth weight of the offspring of the prenatally deprived mothers was significantly less (t=2.63, df=9, p < .05) than the prenatal control litters. Table 1 pre- sents the mean body weight data for the 8 groups from weaning to 61 days. A significant effect was found for maternal dietary restriction during lactation (F=15.63, df=1/10, p<.Ol), but the prenatal diet variable had no measurable effect. At all ages, sub- jects whose mothers were fed the 50% diet during lactation weighed less than those whose mothers were fed ad lib. There was a significant Postnatal Diet x Sex interaction (F=5.74, df= 1/10, pc.05): the body weight of male offspring was more affected by postnatal ma- ternal food restriction than was the body weight of female offspring. As expected, the Sex main effect and the Sex x Age interaction were both significant.

OPEN-FIELD BEHAVIOR

No significant main effects or interactions were found for activity or defecation in the open field.

HEBB-WILLIAMS MAZE

The mean error scores for the Hebb-Williams maze are presented in Table 2. A significant effect (F=6.73,

TABLE 1 . Mean Body Weight at Three Ages

Prenatal Postnatal Days Depriva- Depriva-

tion tion Sex 21 49 61

Male 19.88 158.42 226.19

Female 19.18 125.56 155.75

Male 60.52 238.12 304.37

Female 56.25 123.90 160.67

Yes

Yes

NO

Male 17.05 147.50 221.52

Female 17.12 123.90 160.67

Male 60.45 253.11 335.90

Female 58.51 171.30 195.02

Yes

No

No

MATERNAL FOOD RESTRICTION 9

TABLE 2. Mean Hebb-Williams Error Scores

Postnatal Deprivation

Prenatal Deprivation Yes No

Male 116.25 Male 87.50

Female 134.25 Female 95.25 No

Male 102.75 Male 82.00

Female 118.50 Female 111.00 Yes

df=1/24, f i < . O 5 ) was found for maternal dietary re- striction during lactation: subjects whose mothers were given the 50% diet during lactation made significantly more errors than subjects whose mothers were fed ad lib. No other effect was significant.

DISCUSSION

The purpose of this experiment was to determine if quantitative reduction of mother food intake during gestation and/or lactation would result in reduced offspring intelligence, body weight, and emotionality. The results demonstrated that maternal food restric- tion started during gestation did produce restricted litter birth weight, but this prenatal effect did not continue beyond birth. There were no other weight or behavioral differences due to the prenatal treatment.

Maternal food restriction during lactation affected

both weight and Hebb-Williams performance of the offspring. The weight differences were present at the time of weaning, and there was no recovery even after 40 days of ad tib feeding.

This experiment separated the prenatal and post- natal periods and demonstrated later behavioral and body weight effects for the postnatal period, but no lasting effects for the prenatal period. Previous re- search has not separated these periods in a factorial design, thus making it impossible to isolate the period of development during which the treatment had its effect. Using the present program of treatment, these data clearly point to the postnatal period as critical in determining the later intellectual deficit. However, the present experiment started prenatal food restric- tion within the first 4 days of gestation. Recent re- search has found DNA levels (considered an index of brain cell number) in neonatal offspring adversely affected by maintaining female breeder rats on a low protein diet started 1 month prior to mating (Zamen- hof, Marthens, & Margolis, 1968), but no behaviora1 correlate of this finding was determined. This sug- gests that in order to get a prenatal effect, it may be necessary to have pre-mating dietary restriction that would reduce maternal body reserves prior to gestation.

NOTES

Gilfred Tanabe’s present address is the Department of Psy-

Mailing address: Donald R. Ottinger, Department of Psy- chology, University of Hawaii, Honolulu, Hawaii, U.S.A.

chology, Purdue University, Lafayette, Indiana 47907, U.S.A.

REFERENCES

BARNES, R. H. (1966). Experimental animal approaches to the study of early malnutrition and mental development. Paper presented at the symposium on “Relationship of nutrition to control nervous system development and function.” Annual meeting of the Federation of American Societies for Experi- mental BioIogy, Atlantic City, New Jersey.

BARNES, R. H., CUNNOLD, SUSAN R., ZIMMERMAN, R. R., SIM- MONS, H., MACLEOD, R. B., and KROOK, L. (1966). Influence of nutritional deprivations in early life on learning behavior of rats as measured by performance in a water maze. J. Nutrition,

CHOW, B. F., and LEE, C. J. (1964). Effects of dietary restriction of pregnant rats on body weight gain of offspring. J. Nutrition, 82: 10-18.

89: 399-410.

COWLEY, J. J., and GRIESEL, R. D. (1963). The development of second-generation low protein rats. J. Cen. Psychol., 103: 233- 242.

COWLEY, J. J., and GRIESEL, R. D. (1964). Low protein diet and emotionality in the albino rat. J . Cen. Psychol., 104: 89-98.

DENENBERC, V. H. In press. Open-field behavior in the rat: What does it mean? Ann. N.Y. Acad. Sci.

RABINOVICH, M., and ROSVOLD, H. (1951). A closed-field intelli- gence test for rats. Canad. J . Psychol., 5: 122-128.

ZAMENHOF, S., VAN MARTHENS, EDITH, and MARGOLIS, F. L. (1968). DNA (cell number) and protein in neonatal brain: Alternation by maternal dietary protein restriction. Science, 160: 322-323.