Browsing by Subject "Hypothalamus"
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Compared to casein, bovine lactoferrin reduces plasma leptin and corticosterone and affects hypothalamic gene expression without altering weight gain or fat mass in high fat diet fed C57/BL6J mice(Biomed Central, 2015-12-08)Background Several studies in both humans and rodents have examined the use of lactoferrin as a dietary solution to weight gain and visceral fat accretion and have shown promising results in the short term (up to 7 weeks). This study examined the effects of giving lactoferrin over a longer period of time. Methods For 13 weeks, male C57/BL6J mice were given a diet containing 10 % kJ fat and 20 % kJ casein (LFD) or a diet with 45 % kJ fat and either 20 % kJ casein (HFD) or 20 % kJ lactoferrin (HFD + Lac). Physiological, metabolic, and biochemical parameters were investigated. Gene expression was investigated by Real-Time PCR and microarray. All data was assessed using t-test, ANOVA or ANCOVA. Gene Set Enrichment Analysis was used to interpret microarray data and assess the impact on gene sets with common biological roles. Results By the end of the trial, HFD + Lac fed mice did not alter energy balance, body composition, bodyweight, or weight gain when compared to the HFD group. Notably, there were no changes in subcutaneous or epididymal adipose leptin mRNA levels between high fat diet groups, however plasma leptin was significantly reduced in the HFD + Lac compared to HFD group (P < 0.05) suggesting reduced leptin secretion. Global microarray analysis of the hypothalamus indicate an overall reduction in gene sets associated with feeding behaviour (P < 0.01) and an up-regulation of gene sets associated with retinol metabolism in the HFD + Lac group compared to the HFD group (P < 0.01). Genes in the latter catergory have been shown to impact on the hypothalamic-pituitary-adrenal axis. Notably, plasma corticosterone levels in the HFD + Lac group were reduced compared to the HFD fed mice (P < 0.05). Conclusions The data suggests that prolonged feeding of full-length dietary lactoferrin, as part of a high fat diet, does not have a beneficial impact on weight gain when compared to casein. However, its impact on leptin secretion and accompanying changes in hypothalamic gene expression may underlie how this dietary protein alters plasma corticosterone. The lactoferrin fed mouse model could be used to identify leptin and corticosterone regulated genes in the hypothalamus without the confounding effects of body weight change.
Effect of short term diet restriction on gene expression in the bovine hypothalamus using next generation RNA sequencing technology(Biomed Central, 2017-11-09)Background Negative energy balance (NEB) is an imbalance between energy intake and energy requirements for lactation and body maintenance affecting high-yielding dairy cows and is of considerable economic importance due to its negative impact on fertility and health in dairy herds. It is anticipated that the cow hypothalamus experiences extensive biochemical changes during the early post partum period in an effort to re-establish metabolic homeostasis. However, there is variation in the tolerance to NEB between individual cows. In order to understand the genomic regulation of ovulation in hypothalamic tissue during NEB, mRNA transcriptional patterns between tolerant and sensitive animals were examined. A short term dietary restriction heifer model was developed which induced abrupt onset of anoestrus in some animals (Restricted Anovulatory; RA) while others maintained oestrous cyclicity (Restricted Ovulatory; RO). A third control group (C) received a higher level of normal feeding. Results A total of 15,295 genes were expressed in hypothalamic tissue. Between RA and C groups 137 genes were differentially expressed, whereas between RO and C, 32 genes were differentially expressed. Differentially expressed genes were involved in the immune response and cellular motility in RA and RO groups, respectively, compared to C group. The largest difference between groups was observed in the comparison between RA and RO heifers, with 1094 genes shown to be significantly differentially expressed (SDE). Pathway analysis showed that these SDE genes were associated with 6 canonical pathways (P < 0.01), of which neuroactive ligand-receptor interaction was the most significant. Within the comparisons the main over-represented pathway functions were immune response including neuroprotection (CXCL10, Q1KLR3, IFIH1, IL1 and IL8; RA v C and RA v RO); energy homeostasis (AgRP and NPY; RA v RO); cell motility (CADH1, DSP and TSP4; RO v C) and prevention of GnRH release (NTSR1 IL1α, IL1β, NPY and PACA; RA v RO). Conclusions This information will assist in understanding the genomic factors regulating the influence of diet restriction on fertility and may assist in optimising nutritional and management systems for the improvement in reproductive performance.