title: Effects of pre-weaning energy substitutions on post-weaning follicle development, steroid hormones and subsequent litter size in primiparous sows.
abstract: The present study investigated the effects of pre-weaning energy substitutions on follicular development, endocrine characteristics and subsequent litter size in primiparous sows. Sows were fed a standard lactation diet (14.1 DE MJ/kg) and then allocated to a Control (C, n = 24), Fat (F, n = 23), Sugar (S, n = 23) or post-weaning Regumate (positive control; R, n = 22) treatment at 9 days before weaning of the C, F and S treatments. During the treatment period (8 days), 1 kg of the lactation diet was substituted with 1 kg of a fat-rich (F, 23.85 DE MJ/kg) or sugar-rich (S, 15.75 DE MJ/kg) substitution for F and S sows, respectively. For the R treatment, sows were weaned 8 days earlier than other treatments and fed a lactation diet at 3.5 kg with two doses of altrenogest as topdressing from 1 day before weaning until the day on which the other sows were weaned. The F treatment aimed to increase energy intake, and the S treatment aimed to elevate post-prandial glucose and insulin concentrations. Weaning-to-ovulation interval tended to be reduced in the S treatment compared with C (p = 0.06) and F (p = 0.08) treatments. Body weight (BW) loss during the treatment period, post-weaning follicle development, plasma oestradiol and pre-weaning leptin did not differ among C, F and S sows, although BW loss was lower and leptin was higher in the R treatment. Post-ovulatory progesterone concentration in the S treatment was higher (p < 0.05). Sows in the S and R treatments had a greater proportion of litters with larger litter sizes (p < 0.05). The outcome suggests that increasing circulating insulin and glucose concentrations during late lactation or a week of metabolic recovery positively improves subsequent litter size in primiparous sows.
authors.affiliation: School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia. edgecty@gmail.com
authors.forename: T Y
authors.initials: TY
authors.lastname: Chen
authors.forename: P
authors.initials: P
authors.lastname: Stott
authors.forename: E G
authors.initials: EG
authors.lastname: Bouwman
authors.forename: P
authors.initials: P
authors.lastname: Langendijk
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001724:Birth Weight; D004032:Diet / Q000662:veterinary*; D004041:Dietary Fats / Q000494:pharmacology*; D004734:Energy Metabolism; D004971:Estrus; D005260:Female; D008098:Litter Size; D006080:Ovarian Follicle / Q000502:physiology*; D010060:Ovulation; D010298:Parity; D011247:Pregnancy; D013256:Steroids / Q000097:blood / Q000378:metabolism*; D013552:Swine / Q000502:physiology*; D014886:Weaning
chemical_list: D004041:Dietary Fats; D013256:Steroids