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Updated: Aug 12, 2026
A Swine Model of Neonatal Asphyxia
Published on: October 11, 2011
Animal models for small-for-gestational-age (SGA) neonates and infants-at-risk (IAR)
Insights
Chronic protein deprivation in pregnant rats impacts pup development. Severe deficiency causes small for gestational age (SGA) deficits, while moderate deficiency leads to irreversible changes despite normal birth weight.
Area of Science:
- Nutrition Science
- Developmental Biology
- Animal Models
Background:
- Maternal nutrition significantly influences offspring development.
- Chronic protein deprivation can manifest in overt or hidden forms with distinct consequences.
- Understanding these forms is crucial for developmental health research.
Purpose of the Study:
- To examine body weight changes in rat dams and pups under chronic protein deprivation.
- To differentiate the effects of overt versus hidden protein deficiency on pup development.
- To investigate the long-term impact of early-life nutrition on growth and chemical profiles.
Main Methods:
- Utilized rat models with varying casein-diet percentages (6%, 8%, 25%) to induce protein deprivation.
- Assessed body and brain weights of dams and pups at birth and weaning.
- Conducted cross-fostering experiments to evaluate the reversibility of developmental deficits.
Main Results:
- Overt deprivation (6% casein) resulted in small for gestational age (SGA) pups with irreversible chemical changes.
- Hidden deprivation (8% casein) did not cause SGA but led to irreversible chemical profiles, classifying pups as IAR-neonates.
- Cross-fostering could not fully reverse growth deficits in SGA pups, but normalized weights in IAR-neonates.
Conclusions:
- The 8% casein diet in rats establishes an IAR (Irreversible Altered Response) model due to lasting chemical changes from birth.
- The 6% casein diet creates SGA pups with persistent growth deficits, even after nutritional support via cross-fostering.
- Early-life protein malnutrition has distinct, long-lasting effects on offspring development depending on its severity and form.
Abstract:
In this study, the body weight changes seen in rat dams and brain and body weights seen in pups as sequelae of either an overt or a hidden form of chronic protein deprivation have been examined. In the overt model, the 6% casein-diet pups showed SGA brain and body weight deficits and irreversible central and peripheral chemical changes at birth. In contrast, the hidden form of prenatal deprivation did not result in brain and body weight deficits in the 8% casein-diet pups at birth, but their SGA-like irreversible peripheral and central chemical profiles categorizes them as IAR-neonates. In cross-fostering experiments it was shown that pups from dams fed an 8% casein-diet cross-fostered onto 25% casein-diet dams at birth showed no significant differences in brain or body weight at weaning, whereas pups from 6% casein-diet dams cross-fostered onto 25% casein-diet dams at birth continued to show significantly lower brain and body weights at weaning. These studies show that the 8% casein-diet rat at birth is an IAR model because of its irreversible peripheral and central chemical changes dating form birth, even though the body and brain weights are essentially the same as the pups from 25% casein-diet dams. On the other hand, the pups from 6% casein-diet dams are SGA animals at birth and these brain and body weight deficits at birth cannot be completely reversed at weaning even when the pup is cross-fostered to a 25% casein-diet dam at birth.(ABSTRACT TRUNCATED AT 250 WORDS)
