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Protein deficiency during pregnancy affects fetal development. The critical period, when the fetus is most susceptible to maternal protein deficiency and its effect on neonatal growth, is unknown. Therefore, we studied the effect of a protein-restricted diet during early and late pregnancy and throughout pregnancy on growth of pigs from birth to market weight. Sows were fed a control (13% protein) or protein-restricted (0.5% protein) diet throughout pregnancy or protein-restricted diet from d 1 to 44, then control diet to term or control diet from d 1 to 81, then the protein-restricted diet to term. In Experiment 1, birth weights were measured, and 12 pigs/diet group were weaned at 4 wk and raised to market weight. Feeding the protein-restricted diet throughout pregnancy reduced birth and slaughter weights, whereas the control followed by protein-restricted and protein-restricted followed by control diets reduced only birth weight relative to controls. Indices of carcass lean were reduced in the protein-restricted piglets, with carcass fat not affected. In Experiment 2, control and control-protein-restricted litters were reduced to six piglets and 3/litter cross-fostered to a sow of the other treatment group. After weaning at 4 wk, 4 piglets/group were individually fed to 8 wk. The control and control followed by protein-restricted diet fed piglets had similar weights at birth, but piglets raised by a control-protein-restricted sow tended to weight less at weaning than their littermates raised by a control sow. After weaning, these piglets had greater feed intakes relative to other groups and there were no weight differences by 8 wk.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary protein restriction during pregnancy has an adverse effect on progeny development, although the importance of the time at which the nutritional insult occurs is unclear. The objective in our study was to test the hypothesis that severe protein restriction during the first trimester of swine pregnancy has a greater detrimental effect on fetal development than restriction in late pregnancy. On the day of mating, primiparous swine were assigned to control (C, 13% protein) or protein-restricted (PR, 0.5% protein) diets and fed in 4 regimens: 1) C diet throughout pregnancy (114 +/- 2 days) (n = 5), 2) PR diet to day 44, C diet to parturition (n = 6), 3) C diet to day 80, PR diet to parturition (n = 8), and 4) PR diet throughout pregnancy (n = 6). In addition, 6 pigs fed C and 7 pigs fed PR diets were killed at day 44 to assess placental and fetal development. Maternal diet had no effect on placental or fetal weight, crown-rump length, or heart girth circumference in 44-day fetuses. Mean birth weight of newborn piglets was 1462, 1291, 1262, and 1064 g for C, PR:C, C:PR, and PR groups, respectively (C greater than PR:C = C:PR greater than PR, p less than 0.01). Plasma total protein and albumin were less (p less than 0.01) in PR than in PR:C and C:PR; all three groups were less than C (p less than 0.01). Liver weight and total liver protein, RNA, and DNA followed the same pattern (C greater than PR:C = C:PR greater than PR, p less than 0.05). Longissimus muscle total protein, RNA, and DNA were greater in group C than in all other groups (p less than 0.01). Maternal protein restriction during early pregnancy produced less developmental impairment than restriction throughout pregnancy, but the magnitude of impairment was similar to that produced by restriction during only the third trimester. The effects of early restriction were manifested at birth, even though none of the indices of stunting were observed at 44 days when the maternal protein restriction was ended. Whether the effects of early versus late restriction show the same mechanism of action has not been determined.

To test the hypothesis that maternal protein deprivation in early pregnancy retards body and organ growth of 63-d (midterm) pig fetuses, 16 primiparous domestic four-way crossbred swine were fed a diet adequate in protein (13% protein) (A) or a protein-restricted (0.7% protein) diet (PR) from d 1 to 63 of pregnancy or to parturition. Maternal body weight, plasma protein, hematocrit, and heart and spleen weights were reduced, and indices of body fatness were increased by the PR diet. Fetal body weights were reduced and fetal placental weights were increased at d 63 by protein restriction. Length from crown to rump and weights of liver, kidney, gastrointestinal tract, and cerebrum were lower in PR than in A fetuses. Concentrations of protein, RNA and DNA in liver, cerebrum and longissimus muscle were unaffected by maternal diet, but total amounts of all three constituents in liver and cerebrum were lower in PR than in A. Relative organ weights were similar in A and PR fetuses except that kidneys and gastrointestinal tract were greater in A fetuses. Newborn body weights and absolute organ weights were generally lower in PR than in A, but relative weights were similar. The observed reduction in body and organ weights and amounts of protein, RNA and DNA in 63-d fetuses and newborn progeny of PR swine establishes that the stunting effect of maternal protein restriction can be initiated by midterm, preceding the period of most rapid accretion of body tissues during prenatal life in the pig.

The objective was to determine the effects of maternal gestation diet on mature body and organ size and composition of progeny. Female progeny of swine fed daily 1.8 kg (6,000 kcal DE) of a semipurified diet containing less than 0.5% protein (PR), 1.8 kg (6,000 kcal) of a standard maize-soybean meal-based gestation diet (C) or 0.6 kg (2,000 kcal DE) of C diet to d 70 of gestation and 1.8 kg (6,000 kcal DE) from d 71 to parturition (R) were used. They were fed ad libitum a standard maize-soybean meal-based growing diet to age 25 wk, then continued on limited feed intake to age 62 wk, then returned to ad libitum intake to age 119 wk. Body weight and ultrasonically determined subcutaneous backfat depth were recorded at 62, 79, 97, 105 and 119 wk of age and indices of body composition and organ weights were recorded on carcasses of animals killed at age 119 wk. Progeny of PR dams were permanently stunted in mature body weight and in weights of eviscerated carcass, heart, liver, kidneys, stomach and small intestine, but not in cerebrum, cerebellum weights or RNA and DNA content. It is concluded that severe protein restriction during gestation in swine resulted in permanent whole body weight stunting of progeny but that weights and total protein, RNA and DNA content of cerebrum, cerebellum and RNA and DNA concentration of longissimus muscle were unaffected.

Crossbred (Chester White X Landrace X Large White X Yorkshire) primiparous gilts were fed a standard gestation diet at 6,000 or 2,000 kcal calculated digestible energy (DE; 1.8 or .6 kg feed) daily for 84 or 108 (106 to 112) d after mating. Nonpregnant littermates were matched by body weight and assigned to the same diet treatments. Body weight and ultrasonic backfat measurements were made at 3-wk intervals. At 77 and 100 d, eight pregnant gilts (four control and four restricted) were fitted with indwelling jugular cannulas for frequent blood sampling (33 times over an 8-h period) to determine plasma glucose and growth hormone concentrations. At 84 and 108 d all gilts (eight pregnant and eight nonpregnant at d 84 and nine pregnant and nine nonpregnant at d 108 for each diet) were slaughtered and internal organs and reproductive tracts were removed and weighed. Fetal body and organ weights were recorded and an umbilical artery blood sample was removed from fetuses for plasma glucose, growth hormone, total protein and albumin measurements. The results demonstrated the ability of the primiparous gilt to maintain pregnancy through 106 to 112 d of gestation while consuming one-third (2,000 kcal DE daily) of recommended daily feed. Fetal weight at 84 and 108 d was reduced by about 13% without affecting litter size in gilts fed severely restricted intakes. Absolute and relative weights of maternal organs were affected by severe feed restriction, and backfat was reduced but there was no evidence of "pregnancy anabolism" in either adequately fed or restricted gilts. Fetal liver, kidney and gastrointestinal tract weights were reduced by maternal feed restriction; relative kidney weights were reduced while relative brain cortex weight was increased by maternal restriction. Maternal plasma glucose was unchanged by pregnancy or feed intake while plasma growth hormone peak amplitude, but not mean concentration or number of peaks, was increased by feed restriction. Fetal plasma glucose increased with time and in response to severe maternal feed restriction while plasma total protein and albumin decreased. Plasma growth hormone declined with time and was negatively correlated with fetal body weight.

Genetically obese (O) or lean (L) primiparous gilts were assigned on the day of mating to an adequate [control (C) or restricted (R)] intake of feed. Body weight and ultrasonically estimated backfat depth were recorded at wk 0 (mating), 4, 8, 12 and 16 of pregnancy, and at d 2-3, 21 and 28 of lactation. Number of pigs born, survival rate to 28 d of age and piglet body weight at 0, 14, 21 and 28 d of age were recorded. Four male and four female progeny from each diet group of each genetic strain were slaughtered at 6 mo of age for carcass and organ weight measurements. OR and LR gilts responded similarly to feed restriction in body weight change, backfat depth and plasma traits. Body weight increased throughout gestation in OC and LC gilts but decreased about 6 kg in OR and LR gilts. Backfat remained relatively constant throughout gestation in OC and LC gilts but declined steadily in LR and OR gilts. There were no genetic group x diet interactions for any trait measured. Litter size and piglet survival were not affected by diet or genetic group, but piglet birth weight and daily gain to d 28 and to wk 25 were lower in both R groups. Backfat accretion and other indices of carcass fatness were reduced in progeny of R dams.(ABSTRACT TRUNCATED AT 250 WORDS)

Crossbred (Chester White x Landrace x Large White x Yorkshire) primiparous gilts were fed daily a corn-soybean meal-based gestation diet at 1.8 kg (C) or 0.6 kg (R) (6000 or 2000 kcal calculated digestible energy, DE) or a high-protein diet (RCal) at 0.6 kg (2000 kcal calculated DE) from day of mating to slaughter at 100 to 106 days of gestation. The RCal diet contained three times the concentrations of protein and of mineral and vitamin supplement present in the C diet. Body weight and ultrasonically estimated backfat depth were recorded at 0, 4, 8, and 12 weeks postcoitum. The results showed differential effects of form of diet restriction (R vs RCal) on body weight, backfat depth, relative and absolute uterine weight, and on relative kidney, stomach, and trimmed wholesale cut weights of the dam. Maternal and fetal plasma glucose and urea-N concentrations were higher in RCal than in R groups. Total uterus plus gastrointestinal tract relative weight, with or without fetuses, was lower in RCal than in R and C gilts. The ratio of uterus (with or without fetuses) weight to gastrointestinal tract weight was greater in R than in C or RCal gilts. The data are interpreted to indicate that restriction of carbohydrate-fat calories only compared with restriction of a standard diet throughout gestation in swine had a negative effect on uterine growth associated with repartitioning of nutrients to visceral organ and lean tissue growth at the expense of maternal uterine tissue and body fat conservation.

Rats and swine were restricted in feed during pregnancy to determine the effect on postnatal growth and development of the progeny. Restriction of rats to 50% of preconception feed intake during the first 2 wk of gestation was associated with higher body weight of the progeny at 21 wk postpartum than was ad libitum feeding throughout gestation. However, maternal intake during gestation had no effect on perirenal and gonadal fat weight or adipocyte size in male and female offspring at 160 d of age. Restriction of swine to one-third of recommended feed intake during the first 10 wk of pregnancy was associated in the progeny with less perirenal and subcutaneous backfat and smaller adipocytes in depot fat compared with progeny of adequately fed swine. It is concluded that feed restriction of pregnant rats to one-half of preconception intake for the first two-thirds of pregnancy results in increased weight gain in the resulting progeny while restriction of swine to one-third of the recommended feed allowance during the first two-thirds of pregnancy results in reduced postweaning weight gain and decreased fat accretion during young adulthood.

Second-parity swine were assigned at breeding and continued through two reproduction-lactation cycles (second and third parities, phases one and two) on four dietary treatments as follows: Control (C), 1.8 kg of a standard gestation diet daily (6000 kcal DE daily) to parturition; "Protein-free" (PF), 1.8 kg of a semipurified diet containing less than .5% protein (6000 kcal DE daily) to parturition; Restricted control (R), 0.6 kg of a maize-soybean meal-based gestation diet (C) daily (2000 kcal DE daily) to d 70 of gestation and 1.8 kg daily (6000 kcal DE daily), from d 71 to parturition; Restricted nonprotein calories (RCal), 0.6 kg daily (2000 kcal DE daily) of a diet containing three times the concentrations of protein, vitamins and minerals present in the C diet to d 70 of gestation and 1.8 kg daily (6000 kcal DE daily) of the C diet to parturition. All sows were fed a 16% protein diet ad libitum from parturition to d 28 postpartum. Number of piglets born/litter was unaffected by gestation diet, but individual birth weight was less (P less than .01) in PF than in other progeny in both parities. Postweaning daily weight gain was less (P less than .01) in PF progeny than in other progeny and daily feed intake was less in PF than in C progeny (P less than .05) but intake of PF, R and RCal progeny did not differ. Body weight, chilled carcass weight, carcass length, and weights of trimmed wholesale cuts were less in PF than in other progeny at slaughter. It is concluded that severe protein restriction throughout pregnancy reduces postweaning weight gain of progeny, and that restricting nutrients other than protein and nonprotein calories to one-third of intake recommended by the National Research Council during the first two-thirds of pregnancy does not affect postweaning body weight gain of progeny of swine whose response to the nutritional insult does not result in reduced piglet birth weight.

Pregnant Sprague-Dawley rats were used to determine the effects of the addition of 200 ppm of Cd (as CdCl2) to the diet factorially with two levels of dietary Ca (0.07% and 0.96%) on reproductive performance, concentrations of Cd, Cu, Fe, Zn, Ca and Mg in dam liver and kidney and in newborn progeny. High Cd significantly increased liver and kidney Cd, Zn and Ca and decreased liver Fe. High dietary Ca partially protected against accumulation of Cd in liver and kidney but had no effect on concentration of other elements. Number of live or stillborn pups per litter was not significantly affected by diet but high Cd significantly reduced pup birth weight. No grossly abnormal pups were noted. Concentration of Cd in bodies of newborn pups was increased approximately 8.6-fold by high Cd in the diet of dams fed the 0.07% Ca-diet and 3.8-fold by high-Cd in the diet of dams fed the 0.96% Ca diet. Pup, Zn, Cu and Fe contents were significantly decreased and Ca was significantly increased by high-Cd in the maternal diet whereas pup Mg content was unchanged. Maternal Ca intake had no effect on concentration of Zn, Cu, Fe or Ca in newborn pups. The biological importance of the alteration in maternal and fetal tissue concentration of Zn, Cu and Fe by high-Cd maternal diets is unknown.

Genetically obese (O), and lean (L) and contemporary (C) primiparous swine were assigned from day 30 to 40 of pregnancy to parturition to one of two dietary treatments: 1) 1.8 kg daily (6000 kcal DE) digestible energy, and 2) 0.6 kg daily (2000 kcal DE) of a standard corn-soybean meal-based diet. O gilts weighed less and were fatter at week 16 than L or C gilts. L and C gilts fed the low diet intake maintained constant body weight throughout pregnancy while O gilts gained approximately 10 kg. All gilts fed adequate energy gained weight. Plasma free fatty acids were higher and triglycerides were lower in pregnant gilts fed restricted energy. Plasma cholesterol and blood glucose appeared to be unaffected by genetic background, suggesting that genetic propensity to obesity is not necessarily associated with hypercholesterolemia or hyperglycemia. Pig birth weight was reduced by maternal feed restriction only in O and C pigs; survival was higher in progeny of O dams than in those of L and C dams. Maternal energy restriction had no effect on survival in L, C, or O pigs. Preweaning growth of C but not of L or O progeny was adversely affected by maternal feed restriction. The data illustrate the significance of genetic X gestation energy interactions in dam and progeny traits and suggest that a consideration of genetic background is essential in evaluating response criteria related to feed restriction during pregnancy.

Eighty-eight multiparous sows of four breeds -British Landrace (BL), Chester White (CW), Large White (LW) and Yorkshire(Y)-were mated to boars of their own breed or another breed-BL, Hampshire (H) or Y-to form eight breed groups. All sows were fed daily 1,8 kg of a standard 14% protein gestation diet based on corn-soybean meal through day 100 of pregnancy (6,000 kcal digestible energy/day). From day 100 of gestation to parturition, each sow received either the basal diet (6,000 kcal digestible energy/day) or the basal diet plus 1.82 kg corn starch (12,000 kcal digestible energy/day). All sows were fed a 16% protein corn-soybean meal-based diet ad libitum from day 1 to day 28 of lactation. Energy intake during gestation had no effect on individual pig birth weight, percentage survival or 28-day body weight. There were differences among breeds in pig birth weight (P less than .01) and 28-day weight (P less than .01), and a breed X gestation energy level interaction (P less than .05) was found, but the biological significance is questionable because of the small sample size. Pigs that nursed before blood samples were taken had lower (P less than .01) hematocrit than pigs not allowed to nurse before blood sampling. Energy intake of the dam had no effect on the magnitude of the difference between nursed and nonnursed pigs. We conclude than the normal pregnant dam maintains blood glucose homeostasis during hyperalimentation, thereby rendering ineffective this approach to increasing neonatal growth and survival.

Data on ewe body weights and on lamb birth and weaning weights and survival rates were recorded on a total of 557 multiparous Rambouillet, Hampshire X Suffolk and Synthetic I (composite of Finnish Landrace, Rambouillet and Polled Dorset) ewes in two experiments started after the first trimester of gestation. In Exp. 1, a 2 X 2 factorial arrangement of treatments included all combinations of low (.24% in gestation and .48% in lactation), or high (.80%) dietary Ca and low (20 ppm) or high (74 ppm) dietary Zn. No effect of dietary Ca or Zn level and no Ca X Zn interaction with respect to number of lambs born or weaned, birth weight, weaning weight or survival rate of the lambs or body weight of the ewes was shown. Mean number of lambs born was 1.63 +/- .71 with a survival rate of 85.0 +/- .3% and a weaning weight (59 d) of 19.4 +/- 4.4 kg. Experiment 2 was a repeat of Exp. 1 except that two intramuscular injections of vitamins A, D and E (d 65 and 93 of experiment) were given to one-half of the ewes in each diet group. There was no effect of dietary Ca or Zn level or of vitamin administration on ewe body weight changes, number of lambs born (1.89 +/- .55), survival rate (86.6 +/- .3%), lamb birth weight 4.6 +/- 1.5 kg) or lamb weaning weight (23.2 +/- 7.2 kg). Blood plasma Ca, inorganic P and Mg concentrations of ewes in late pregnancy were unaffected by diet or vitamin injections.(ABSTRACT TRUNCATED AT 250 WORDS)