Browsing by Author "Loor, J. J."
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- Effects of dietary cis 9, trans 11-18 : 2, trans 10, cis 12-18 : 2 or vaccenic acid (trans 11-18 : 1) during lactation on body composition, tissue fatty acid profiles, and litter growth in miceLoor, J. J.; Lin, X. B.; Herbein, J. H. (Cambridge University Press, 2003-12)Cis 9, trans 11 (c9, t11)-18:2 and trans 10, cis 12 (t10, c12)-18:2 are the major conjugated linoleic acid (CLA) isomers in dietary supplements which reduce milk fat content in nursing women. The present study evaluated the effects of each CLA isomer or vaccenic acid on body composition and tissue fatty acids during lactation in mice. Dams were fed 30 g rapeseed oil (control)/kg diet or 20 g control plus 10 g 18: 0, trans 11-18: 1 (t11-18 : 1), c 9, t1 1-18: 2, or t10, c12-18: 2. Dietary t10, c12-18: 2 reduced food intake by 18 % and carcass fat weight of the dams by 49 % compared with the other treatments. Milk fat percentage ranked by treatment was 18: 0 > t1 1-18: 1 = c 9, t11-18:2 > t10, c12-18:2. The sum of saturated 12:0 to 16:0 in milk fat was lower when c9, t11-18:2 was fed compared with the control, 18:0, or t11-18: 1 treatments. Dietary t10, c12-18:2 caused further reductions in milk fat 12:0 to 16:0. The proportion of CLA isomers was 3-fold greater in milk fat than in the carcasses of the dams. The pups nursing from the dams fed t10, c12-18:2 had the lowest body weights and carcass fat, protein, and ash contents. Nursing from the dams fed c9, t1 l-18:2 also resulted in lower carcass fat compared with the 18:0 or t1 l-18 : 1 treatments. The ratios of cis 9-16: 1:16:0 or cis 9-18: 1:18:0, proxies for Delta(9)-desaturase activity, were markedly lower in the carcasses of the dams and pups fed t10, c12-18: 2. The ratio of 20: 4n-6:18: 2n-6, a proxy for Delta(6)- and Delta(5)-desaturase and elongase activity, in the liver of the dams and pups fed t10, c12-18: 2 also was lower. Dietary t1 l-18 : 1 enhanced the content of c9, t1 l-18 : 2 in milk fat and carcasses. As in previous studies, the reduction in food intake by t10, c12-18: 2 could not entirely account for the marked decrease in carcass fat content and milk fat concentration. T10, c12-18: 2 probably had a negative effect on Delta(9)-desaturase and mammary de novo fatty acid synthesis. Although these effects need to be confirmed in lactating women, the results suggest that the consumption of supplements containing t10, c12-18: 2 should be avoided during the nursing period.
- Higher plane of nutrition pre-weaning enhances Holstein calf mammary gland development through alterations in the parenchyma and fat pad transcriptomeVailati-Riboni, M.; Bucktrout, R. E.; Zhan, S.; Geiger, A.; McCann, J. C.; Akers, Robert Michael; Loor, J. J. (2018-12-11)Background To reduce costs of rearing replacement heifers, researchers have focused on decreasing age at breeding and first calving. To increase returns upon initiation of lactation the focus has been on increasing mammary development prior to onset of first lactation. Enhanced plane of nutrition pre-weaning may benefit the entire replacement heifer operation by promoting mammary gland development and greater future production. Methods Twelve Holstein heifer calves (< 1 week old) were reared on 1 of 2 dietary treatments (n = 6/group) for 8 weeks: a control group fed a restricted milk replacer at 0.45 kg/d (R, 20% crude protein, 20% fat), or an accelerated group fed an enhanced milk replacer at 1.13 kg/d (EH, 28% crude protein, 25% fat). At weaning (8 weeks), calves were euthanized and sub-samples of mammary parenchyma (PAR) and mammary fat pad (MFP) were harvested upon removal from the body. Total RNA from both tissues was extracted and sequenced using the Illumina HiSeq2500 platform. The Dynamic Impact Approach (DIA) and Ingenuity Pathway Analysis (IPA) were used for pathway analysis and functions, gene networks, and cross-talk analyses of the two tissues. Results When comparing EH vs R 1561 genes (895 upregulated, 666 downregulated) and 970 genes (506 upregulated, 464 downregulated) were differentially expressed in PAR and MFP, respectively. DIA and IPA results highlight a greater proliferation and differentiation activity in both PAR and MFP, supported by an increased metabolic activity. When calves were fed EH, the PAR displayed transcriptional signs of greater overall organ development, with higher ductal growth and branching, together with a supportive blood vessel and nerve network. These activities were mediated by intracellular cascades, such as AKT, SHH, MAPK, and Wnt, probably activated by hormones, growth factors, and endogenous molecules. The analysis also revealed strong communication between MFP and PAR. Conclusions The transcriptomics and bioinformatics approach highlighted key mechanisms that mediate the mammary gland response to a higher plane of nutrition in the pre-weaning period.