Impact of Diet Deprivation and Subsequent Over-Allowance during Prepuberty on Growth Performance, Metabolite Status and Mammary Gland Development in Gilts

November 2, 2011 — 

The impact of diet deprivation and subsequent over-allowance on the metabolite status, mammary development, and mammary gene expression in prepubertal gilts was determined. Forty-seven gilts were reared under a conventional (control, CTL; n = 23) or an experimental (treatment, TRT; n = 24) dietary regimen. The later regimen (consisting of diet deprivation and subsequent over-allowance) provided 70 (restricting diet, R) 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 BW as follows: 3 wk R, 3 wk OVER, 4 wk R, and 4 wk OVER. At each diet change, weights and individual feed intakes were measured, and blood samples for metabolite and IGF-I assays were obtained. Some gilts (11 CTL and 12 TRT) were slaughtered on d 235 (after reaching puberty) to collect mammary tissue for compositional analyses and measures of gene expression. Weight gain (P < 0.01) and G:F (P < 0.05) of gilts were reduced during each period with the R diet; however, there was no compensatory growth during the periods when the OVER diet was fed periods. Feeding the R diet reduced concentrations of urea and IGF-I (P < 0.01) and feeding the OVER diet increased FFA (P < 0.01) and glucose (P < 0.10) in TRT gilts compared with CTL gilts. The TRT gilts had less parenchymal tissue (P < 0.05) and tended to have less total parenchymal fat and protein (P < 0.1) than CTL gilts. The mammary mRNA relative abundance of the signal transducers and activators of transduction 5B was lower in TRT than CTL gilts (P < 0.05). In conclusion, the diet deprivation and over-allowance regimen used in the growing-finishing period did not have beneficial effects on mammary development after puberty. In fact, a detrimental effect was observed.

Farmer C, Palin MF, Martel-Kennes Y. Agriculture and Agri-Food Canada, Dairy and Swine R & D Centre, 2000 College St., Sherbrooke, Québec J1M 0C8, Canada. J Anim Sci. 2011 Oct 14. [Epub ahead of print] http://www.ncbi.nlm.nih.gov/pubmed/22003231