Nutrient restriction in late foetal life permanently alters lambs’ metabolic priorities
Take Home Message: Nutrient restriction in late pregnancy improves the ability of lambs to convert feed into growth, but due to the reduced milk production of the ewe lamb liveweight is lower throughout the finishing period.
A 50% reduction of maternal nutrient supply in the final six weeks of gestation reduces lambs’ birth weight and pre-weaning growth due to lower milk intake. Just two of the findings of a trial, carried out by scientists in Denmark and Australia, to investigate the effects of maternal nutrient restriction in late gestation on offspring’s postnatal metabolism and performance.
“Postnatal growth rates were determined by current level of nutrition, being reduced in low-nutrition lambs pre-weaning due to lower milk production by the dam, but restored to normal when an adequate post-weaning diet was provided,” said the University of Copenhagen’s Malin Tygesen.
“We found that prenatal undernutrition lowered plasma insulin in postnatal life, resulting in an improved capacity to convert ingested feed into lean rather than fat growth.
“And we think that the differences observed in fractional growth rates, feed conversion ratios and growth pattern are likely to be expressions of a metabolic programming induced in low-nutrition lambs by nutrient restriction in late foetal life. This is a programming that has permanently altered the metabolic priorities and endocrine function of the body,” he added.
His team also found that prenatal undernutrition may programme postnatal metabolism and the glucose–insulin axis differentially depending on sire genotype, thus affecting the ability of the ad-lib fed lamb to exhibit compensatory growth and achieve a given body weight by a certain age.
Forty purebred Shropshire twin lambs born to ewes fed either a high-nutrition diet or a low-nutrition diet during the final six weeks of gestation were studied from birth until 145 days of age. Post partum all ewes were fed the same diet.
Lambs born to low-nutrition ewes had significantly lower birth weights and pre-weaning growth rates. Low-nutrition lambs converted milk to live weight with an increased efficiency in week three of life. Their glucose concentrations and growth rates were both increased. Plasma glucose concentrations in low-nutrition lambs became similar to those observed in high-nutrition lambs post-weaning.
But low-nutrition lambs continued to be lighter than the other groups throughout the experimental period and were unable to compensate for the reduced weight at birth despite having the highest daily fractional growth rates.
“Growth rates can be restored when an adequate post-weaning diet is provided, but the
prenatal nutrition may programme postnatal metabolism differentially depending on genotype, thus affecting the ability of the ad-lib fed lamb to achieve a given body weight by a certain age,” added Dr Tygesen.
Full paper.pdf
Full details: Tygesen MP, Tauson AH, Blache D, Husted SM and Nielsen MO: “Late foetal life nutrient restriction and sire genotype affect postnatal performance of lambs.” Animal 2: 574-581.
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