title: Hyperinsulinaemia, supplemental protein and branched-chain amino acids when combined can increase milk protein yield in lactating sows.
abstract: The aim of this study was to determine whether dietary supplementation with branched-chain amino acids, and the infusion of insulin and dextrose, would increase milk protein secretion in the sow. The experiment involved sixteen lactating sows fed either a normal lactation diet (162 g/kg crude protein, n 8) or a high-protein diet (230 g/kg crude protein, n 8) supplemented with branched-chain amino acids (valine, isoleucine and leucine). Sows were either infused with insulin and dextrose or not infused at all during mid (day 5-10) and late (day 17-22) lactation in a single reversal design. Blood samples were analysed for glucose, and the dextrose infusion rate was adjusted to maintain the blood glucose level within 15 % of pre-infusion levels. Milk (10.1 v. 11.1 kg/d; P=0.014) and lactose (628 v. 727 g/d; P=0.002) yield increased with insulin infusion, whereas milk protein content (5.0 % v. 5.5 %; P=0.007) was increased in diets supplemented with protein and branched-chain amino acids. Piglet growth was increased by feeding the higher-protein diet (237 v. 273 g/d; P=0.05) but not significantly increased by insulin infusion (245 v. 265 g/d; P=0.11). These effects were additive such that the combined treatment resulted in a 24 % (56 g/d; P<0.05) increase in piglet growth rate. These data demonstrate that increasing the dietary protein/branched-chain amino acid content can increase milk protein secretion but not milk yield. The infusion of insulin and dextrose increased milk and milk lactose yields, and tended to increase milk protein yield but not milk protein content. These effects are additive and translate to increased protein yield and piglet growth.
authors.affiliation: Department of Animal Science, Cornell University, Ithaca, NY14853, USA. Frank.Dunshea@dpi.vic.gov.au
authors.forename: Frank R
authors.initials: FR
authors.lastname: Dunshea
authors.forename: Dale E
authors.initials: DE
authors.lastname: Bauman
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Nugent
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Kerton
authors.forename: Raymond H
authors.initials: RH
authors.lastname: King
authors.forename: Ian
authors.initials: I
authors.lastname: McCauley
mesh_terms: D000597:Amino Acids, Branched-Chain / Q000494:pharmacology*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology; D019587:Dietary Supplements; D005260:Female; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D007774:Lactation / Q000187:drug effects; D007785:Lactose / Q000378:metabolism; D008894:Milk Proteins / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D013552:Swine / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000597:Amino Acids, Branched-Chain; D001786:Blood Glucose; D004044:Dietary Proteins; D007328:Insulin; D008894:Milk Proteins; D005947:Glucose; D007785:Lactose