title: Placental restriction in multi-fetal pregnancies and between-twin differences in size at birth alter neonatal feeding behaviour in the sheep.
abstract: Most individuals whose growth was restricted before birth undergo accelerated or catch-up neonatal growth. This is an independent risk factor for later metabolic disease, but the underlying mechanisms are poorly understood. This study aimed to test the hypothesis that natural and experimentally induced in utero growth restriction increase neonatal appetite and milk intake. Control (CON) and placentally restricted (PR) ewes carrying multiple fetuses delivered naturally at term. Outcomes were compared between CON (n=14) and PR (n=12) progeny and within twin lamb pairs. Lamb milk intake and feeding behaviour and ewe milk composition were determined using a modified weigh-suckle-weigh procedure on days 15 and 23. PR lambs tended to have lower birth weights than CON (-15%, P=0.052). Neonatal growth rates were similar in CON and PR, whilst heavier twins grew faster in absolute but not fractional terms than their co-twins. At day 23, milk protein content was higher in PR than CON ewes (P=0.038). At day 15, PR lambs had fewer suckling bouts than CON lambs and in females light twins had more suckling attempts than their heavier co-twins. Birth weight differences between twins positively predicted differences in milk intakes. Lactational constraint and natural prenatal growth restriction in twins may explain the similar milk intakes in CON and PR. Within twin comparisons support the hypothesis that prenatal constraint increases lamb appetite, although this did not increase milk intake. We suggest that future mechanistic studies of catch-up growth be performed in singletons and be powered to assess effects in each sex.
authors.affiliation: 1Department of Food and Wine Science,School of Agriculture, Food and Wine,FOODplus Research Centre,The University of Adelaide,Adelaide,SA,Australia.
authors.forename: R F
authors.initials: RF
authors.lastname: Peter
authors.affiliation: 1Department of Food and Wine Science,School of Agriculture, Food and Wine,FOODplus Research Centre,The University of Adelaide,Adelaide,SA,Australia.
authors.forename: J
authors.initials: J
authors.lastname: Gugusheff
authors.affiliation: 2Discipline of Obstetrics and Gynaecology,Adelaide Medical School,Adelaide,SA,Australia.
authors.forename: A L
authors.identifier: http://orcid.org/0000-0002-2914-7693
authors.initials: AL
authors.lastname: Wooldridge
authors.affiliation: 2Discipline of Obstetrics and Gynaecology,Adelaide Medical School,Adelaide,SA,Australia.
authors.forename: K L
authors.identifier: http://orcid.org/0000-0002-2823-3004
authors.initials: KL
authors.lastname: Gatford
authors.affiliation: 1Department of Food and Wine Science,School of Agriculture, Food and Wine,FOODplus Research Centre,The University of Adelaide,Adelaide,SA,Australia.
authors.forename: B S
authors.initials: BS
authors.lastname: Muhlhausler
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000833:Animals, Suckling / Q000502:physiology*; D001724:Birth Weight / Q000502:physiology*; D049628:Body Size / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D005317:Fetal Growth Retardation / Q000378:metabolism*; D008098:Litter Size / Q000502:physiology*; D008297:Male; D008892:Milk / Q000502:physiology; D010920:Placenta / Q000502:physiology*; D011247:Pregnancy; D012756:Sheep
keywords: catch-up growth; fetal growth restriction; milk composition; milk intake; newborn