Endocrinology of nutritional flushing in gilts

Abstract

As part of a nutritional flushing study, the endocrine status of gilts was compared to gain further knowledge of the mechanism(s) that mediate the restoration of ovulation rate. From a5.3 kg BW to puberty,42 grlts were fed 2.0 kg d-' (L) d'une fr6quence accrue des d6charges 6pisodiques de pLH. En outre, les truies HH accusaient des concentrations plasmatiques d'insuline sup6rieures (P < 0.05) )r celles des truies LL tout au long de la p6riode p6ri-oestrale, et leurs concentrations en IGF-I 6taient plus 6lev6es lors des pics de s6cr6tion de pLH. Ces r6sultats confortent I'hypothdse vouiant que I'accroissement de la teneur en insuline du plasma soit un indicateur m6tabolique important qui, soit ind6pendamment ou en synergie avec les gonadotropines et avec IGF-I, modulerait la rdponse ovulatoire ir la suralimentation.

Premating and gestational effects of maternal nutrition on secondary sex ratio in house mice

“…Meikle and Drickamer (1986) did not find that premating females had higher fertility or fecundity (litter size). Increased food availability is usually associated with greater fertility and fecundity (Bronson, 1989), but reduced food intake, followed by abundant food just before mating is often used to increase fertility and fecundity in the production of some domestic animals (Beltranena et al, 1991 (Labov et al, 1986). The relatively low mass of adult males born to food-deprived mothers reduces the probability that they will establish and maintain a territory (Vessey, 1967;Krackow, 1993), and they may therefore have rela¬ tively low reproductive potential (Wolff, 1985).…”

Influence of different planes of energy supply prior to the breeding season on blood metabolites in female mink (Mustela vison)

“…Previous studies with sheep [22] and mink [17] [34] and pigs [5]. Blood glucose is the primary energy substrate used at the cellular level, and reduced concentrations may influence body composition [26].…”

“…Flushing has shown positive effects on reproductive performance in different species (gilt: Flowers et al [18]; Beltranena et al [5]; ewe: Haresign [21] and mink: review by Tauson [29]), and because of responsiveness to nutritional changes, it has been hypothesized that some metabolic factors may provide the links between nutrition and reproduction [23].…”

“…Flushing is defined as a period of restricted feeding followed by refeeding, preceding the oestrous period or breeding season [13], and occurs over such a short period that there is usually not a significant change in female body composition [5,11]. Flushing has shown positive effects on reproductive performance in different species (gilt: Flowers et al [18]; Beltranena et al [5]; ewe: Haresign [21] and mink: review by Tauson [29]), and because of responsiveness to nutritional changes, it has been hypothesized that some metabolic factors may provide the links between nutrition and reproduction [23].…”

Recombinant porcine somatotropin effects on sexual development and metabolic status of gilts

“…Furthermore, Kirkwood et al (1989b) reported that, despite a30% depression in feed intake, pST-injected gilts (90 pg kg-'for 9 d) had ovulation rates comparable to those of vehicle-injected gilts. This observation is of interest because daily injections of insulin (Cox et al 1987) and shortterm increases in feeding level during the first estrous cycle (Beltranena et al 1991) have been shown to increase ovulation rate in gilts. However, the mechanism by which ovulation rate is sustained in pST-treated gilts, despite the depression in feed intake, has yet to be clarifred.…”