Impact of diet deprivation and subsequent over-allowance during prepuberty. Part 2. Effects on mammary gland development and lactation performance of sows1

Abstract

The impact of diet deprivation and subsequent over-allowance in prepubertal gilts on their mammary development and mammary gene expression at the end of gestation and their lactation performance over 2 parities was determined. Seventy-seven gilts were reared under a conventional (control, CTL; n = 41) or an experimental (treatment, TRT; n = 36) dietary regimen. The experimental regimen provided 70 (restriction diet, RES) and 115% (over-allowance diet, OVER) of the protein and DE contents provided by the CTL diet. Experimental diets were fed ad libitum starting at 27.7 ± 3.4 kg of BW as follows: 3 wk RES, 3 wk OVER, 4 wk RES, and 4 wk OVER. All gilts were bred, and 34 were slaughtered on d 110 of gestation (18 CTL and 16 TRT) to collect mammary tissue for compositional analyses and gene expression measurements. Remaining gilts (23 CTL and 20 TRT) were maintained for 2 parities, and litter performance data were obtained. Blood samples for hormonal and metabolite assays were obtained on d 110 of gestation from all sows slaughtered at that time and from 14 sows per treatment on d 2 and 17 of lactation in the first parity. Milk samples were obtained from these same sows on d 17 of lactation in both parities. There was a tendency for mammary parenchymal tissue to contain less protein in TRT than CTL sows (P < 0.10), and relative mRNA abundance of the signal transducer and activator of transduction 5B gene was increased in parenchyma from TRT sows (P < 0.05). Circulating prolactin (P < 0.05) and milk lactose concentrations (P < 0.01) were less, whereas milk protein content was greater (P < 0.05) in TRT sows than CTL sows on d 17 of lactation. Nevertheless, growth rate of suckling piglets over the first 2 parities was unaffected by treatment. In conclusion, the use of a diet deprivation and over-allowance regimen in the growing-finishing period did not have beneficial effects on mammary gene expression or on sow and piglet performance.

Impact of diet deprivation and subsequent overallowance during gestation on mammary gland development and lactation performance1

“…The current results demonstrate that diet deprivation followed by overallowance during the gestation period only (using a dietary regimen similar to that of Crenshaw et al [1989]) does not improve mammary development at the end of gestation or lactation and does not improve piglet growth rate (i.e., milk yield). It was previously shown that such a dietary regimen in only the growing-finishing period has no beneficial effect on mammary development at the end of gestation (Farmer et al, 2012b), and one would therefore expect that the positive effects observed by Crenshaw et al (1989) were most likely due to a gestation effect. Yet the current results do not support that theory.…”

“…Milk samples (200 μL) were centrifuged at 5000 × g for 15 min at room temperature, and the aqueous phase (skim milk) was collected and conserved at -20°C until used for protein quantification. Casein β and whey acidic protein (WAP) protein quantifications were performed using dot blot analyses as previously described (Farmer et al, 2012b).…”

“…In swine, Crenshaw et al (1989) reported that diet deprivation followed by overallowance during the growing, finishing, and gestation phases increased sow milk yield and stimulated the relative expression of CSN2 in mammary tissue. It was recently demonstrated that using the same feeding regimen only in the growing-finishing period had no beneficial effect on mammary development at puberty (Lyvers-Peffer and Rozeboom, 2001;Farmer et al, 2012a) or at the end of gestation (Farmer et al, 2012b). This indicates that the gestation period could be the most sensitive physiological state to stimulate mammogenesis.…”

Epigenetics and developmental programming of welfare and production traits in farm animals

“…There is evidence of both positive (Crenshaw et al 1989) and negative (Farmer et al 2012a) effects of 'stair-step' feeding on mammary gland development, but with little effect on piglet performance (Farmer et al 2012b). It is difficult to reconcile these mixed results in pigs with the more clear-cut findings in cattle, other than to observe that in the studies cited above there was no evidence of compensatory growth in restricted-overfed gilts, which, at the end of the experimental periods, were lighter than matched control-fed gilts.…”

Nutritional impact on mammary development in pigs: a review

“…In fact, this feeding regime led to a decrease in parenchymal tissue mass (Farmer et al, 2012a). This same nutritional treatment also did not affect parenchymal mass at the end of gestation but led to a tendency for reduced percent protein in mammary parenchyma (Farmer et al, 2012b). It is important to note that in those 2 studies by Farmer et al (2012a,b), no compensatory growth was observed in gilts at the end of the finishing period.…”