A Mother’s Carnitine Boost Shapes Newborn Rabbits’ Metabolism, Study Finds

What a mother eats during pregnancy and nursing may quietly program the metabolism of her offspring long before they can eat a single meal on their own. That is the central message of a new study on New Zealand White rabbits, published in the journal Archives Animal Breeding, which found that supplementing pregnant and lactating does with L-carnitine, a vitamin-like compound central to cellular energy production, produced measurably healthier, faster-growing babies. The work, led by Shahzada Khurram Adrian Shah and Rifat Ullah Khan of The University of Agriculture in Peshawar, together with collaborators in Türkiye, Saudi Arabia, Italy and the United States, offers some of the most detailed evidence yet that maternal nutrition can leave a metabolic fingerprint on newborn animals.

The research team worked with 160 five-month-old, first-time pregnant does, each weighing around 2.84 kilograms on average. The animals were randomly divided into four groups: one received plain drinking water, while the other three received L-carnitine dissolved in their water at concentrations of 100, 200 or 300 milligrams per liter. Crucially, the supplementation began as soon as pregnancy was confirmed, roughly ten to twelve days after mating, and continued through the entire gestation and lactation periods. This design allowed the researchers to capture what they call carry-over effects, meaning benefits passed from mother to offspring through the placenta before birth and through milk afterward, rather than effects of the compound fed directly to the young.

L-carnitine is a naturally occurring molecule with a very specific job inside the body: it shuttles long-chain fatty acids across the inner mitochondrial membrane so they can be burned for energy through a process called beta-oxidation. Without enough of it, cells struggle to convert fat into usable fuel. It also plays supporting roles in glucose metabolism, helping activate the enzyme pyruvate dehydrogenase so that sugar breakdown products can enter the energy-generating Krebs cycle, and it can spare the amino acids lysine and methionine for protein synthesis. Because fetal and newborn animals synthesize very little carnitine on their own, they depend almost entirely on what their mothers supply through the placenta and, later, through milk.

The results were striking, particularly at the highest dose. Newborn kits whose mothers received 300 milligrams of L-carnitine per liter of water showed the highest individual body weights at 21 days of age and the greatest average daily gain over the first three weeks of life, outperforming both the unsupplemented control group and the lower-dose groups. Litter sizes also trended upward in the supplemented groups, with the mid-dose group showing the largest litters at weaning age. In practical terms, the offspring of supplemented mothers were simply growing faster, a sign that energy was flowing more efficiently from mother’s milk into growing tissue.

Blood analyses of the neonates, conducted during weeks one, two and three of life, revealed what was happening beneath the surface. Serum glucose concentrations were significantly elevated in the highest-dose group across all three weeks, which the authors interpret not as a warning sign but as evidence of improved energy availability and metabolic flexibility. When growth is accelerating and thyroid activity is rising, higher circulating glucose more likely reflects better nutrient delivery and more efficient carbohydrate oxidation than any metabolic dysfunction. Cholesterol and triglyceride levels, by contrast, were largely unaffected, suggesting the compound was fine-tuning energy use without disrupting lipid handling.

Two liver enzymes, aspartate aminotransferase and alanine aminotransferase, told an equally encouraging story. These enzymes leak into the bloodstream when liver cells are stressed or damaged, so lower levels generally indicate a healthier liver. In the highest-dose group, both enzymes dropped significantly during the later weeks of the study compared with controls. The researchers attribute this hepatoprotective effect to L-carnitine’s ability to keep mitochondrial fat burning running smoothly, preventing fat from accumulating inside liver cells and reducing the production of reactive oxygen species that can destabilize cell membranes.

Perhaps the most telling hormonal shift involved the thyroid. Triiodothyronine, or T3, the biologically active thyroid hormone that drives oxygen consumption, thermogenesis and protein synthesis, was consistently highest in the neonates of the 300-milligram group throughout all three weeks. Thyroxine, or T4, was also elevated in the higher-dose groups by the second and third weeks. Since thyroid hormones stimulate mitochondrial biogenesis and cellular energy production, their rise dovetails neatly with the faster growth observed. The authors suggest that improved mitochondrial function may have boosted the conversion of T4 into the more active T3, creating a feedback loop in which better energy metabolism and stronger endocrine signaling reinforce each other.

Not every measured parameter moved, and those null results matter too. Cortisol, the primary stress hormone, remained unchanged across all groups, indicating that the supplementation did not disturb the animals’ baseline stress physiology. Malondialdehyde, a standard marker of oxidative damage to fats, also showed no significant differences, which the team reads as evidence that lipid peroxidation was already well controlled and that the enhanced energy metabolism came without oxidative costs. In other words, the metabolic boost did not come at the price of cellular wear and tear, a balance that is essential for any intervention intended to improve health rather than merely accelerate growth.

The findings fit into a growing body of research on what scientists call nutritional programming, the idea that the nutritional environment experienced in early life, even before birth, can shape metabolism, endocrine function and health trajectories later on. Most previous studies of L-carnitine in livestock focused on feeding it directly to growing animals or on its effects on the reproductive performance of breeding females. By tracking a full panel of biochemical, hormonal and oxidative markers in newborns whose mothers alone were supplemented, this study fills an important gap and suggests that the maternal supply line, from placenta to milk, is a powerful lever for shaping offspring development.

For commercial rabbit farming, an industry valued for its high reproductive efficiency and rapid production of lean protein, the practical implications are tempting. Supplementation via drinking water at 300 milligrams per liter was well tolerated, produced no adverse effects on liver integrity, stress hormones or oxidative status, and delivered heavier, faster-growing kits. The authors caution, however, that adoption should await cost-benefit analyses under real commercial conditions, and that future work should include a broader panel of antioxidant enzymes, such as glutathione peroxidase and superoxide dismutase, to fully map how maternal carnitine reshapes the antioxidant defenses of the next generation. If those results hold up, a simple addition to a mother’s water may prove to be one of the cheapest ways to give newborn animals a stronger metabolic start in life.

Subject of Research: Maternal L-carnitine supplementation during gestation and lactation and its carry-over metabolic effects on neonatal rabbits

Article Title: Carry-over influence of maternal L-carnitine during gestation and lactation on metabolic response of New Zealand neonatal rabbits

Article References: Shah, S. K. A., Khan, H., Ülger, İ., Alonaizan, R., Naz, S., Alomar, S., Tashkandi, N. A., Abudabos, A., Rossi, L., & Khan, R. U. (2026). Carry-over influence of maternal L-carnitine during gestation and lactation on metabolic response of New Zealand neonatal rabbits. Archives Animal Breeding, 69(4), 585-594. https://doi.org/10.5194/aab-69-585-2026

Image Credits: AI Generated

DOI: 10.5194/aab-69-585-2026

Keywords: L-carnitine, maternal nutrition, nutritional programming, neonatal rabbits, metabolism, thyroid hormones, mitochondria, animal science, liver enzymes, oxidative stress, rabbit farming, gestation