143 research outputs found
Use of high-density SNP data to identify patterns of diversity and signatures of selection in broiler chickens
The development of broiler chickens over the last 70 years has been accompanied by large phenotypic changes, so that the resulting genomic signatures of selection should be detectable by current statistical techniques with sufficiently dense genetic markers. Using two approaches, this study analysed high‐density SNP data from a broiler chicken line to detect low‐diversity genomic regions characteristic of past selection. Seven regions with zero diversity were identified across the genome. Most of these were very small and did not contain many genes. In addition, fifteen regions were identified with diversity increasing asymptotically from a low level. These regions were larger and thus generally included more genes. Several candidate genes for broiler traits were found within these ‘regression regions’, including IGF1,GPD2 and MTNR1AI. The results suggest that the identification of zero‐diversity regions is too restrictive for characterizing regions under selection, but that regions showing patterns of diversity along the chromosome that are consistent with selective sweeps contain a number of genes that are functional candidates for involvement in broiler development. Many regions identified in this study overlap or are close to regions identified in layer chicken populations, possibly due to their shared precommercialization history or to shared selection pressures between broilers and layers
Urinary C-Peptide Measurement as a Marker of Nutritional Status in Macaques
Studies of the nutritional status of wild animals are important in a wide range of research areas such as ecology, behavioural ecology and reproductive biology. However, they have so far been strongly limited by the indirect nature of the available non-invasive tools for the measurement of individual energetic status. The measurement of urinary C-peptide (UCP), which in humans and great apes shows a close link to individual nutritional status, may be a more direct, non-invasive tool for such studies in other primates as well and possibly even in non-primate mammals. Here, we test the suitability of UCPs as markers of nutritional status in non-hominid primates, investigating relationships between UCPs and body-mass-index (BMI), skinfold fatness, and plasma C-peptide levels in captive and free-ranging macaques. We also conducted a food reduction experiment, with daily monitoring of body weight and UCP levels. UCP levels showed significant positive correlations with BMI and skinfold fatness in both captive and free-ranging animals and with plasma C-peptide levels in captive ones. In the feeding experiment, UCP levels were positively correlated with changes in body mass and were significantly lower during food reduction than during re-feeding and the pre-experimental control condition. We conclude that UCPs may be used as reliable biomarkers of body condition and nutritional status in studies of free-ranging catarrhines. Our results open exciting opportunities for energetic studies on free-ranging primates and possibly also other mammals
The association of body size in early to mid-life with adult urinary 6-sulfatoxymelatonin levels among night shift health care workers
Melatonin improves non-alcoholic fatty liver disease via MAPK-JNK/P38 signaling in high-fat-diet-induced obese mice
Daily Melatonin Administration to Middle-Aged Male Rats Suppresses Body Weight, Intraabdominal Adiposity, and Plasma Leptin and Insulin Independent of Food Intake and Total Body Fat
Assessment of Murine Exercise Endurance Without the Use of a Shock Grid: An Alternative to Forced Exercise
Blunted hypothalamic neuropeptide gene expression in response to fasting, but preservation of feeding responses to AgRP in aging male Brown Norway rats
Daily Melatonin Administration to Middle-Aged Male Rats Suppresses Body Weight, Intraabdominal Adiposity, and Plasma Leptin and Insulin Independent of Food Intake and Total Body Fat
Pineal melatonin secretion declines with aging, whereas visceral
fat, plasma insulin, and plasma leptin tend to increase. We have
previously demonstrated that daily melatonin administration at middle
age suppressed male rat intraabdominal visceral fat, plasma leptin,
and plasma insulin to youthful levels; the current study was
designed to begin investigating mechanisms that mediate these responses.
Melatonin (0.4 mg/ml) or vehicle was administered in the
drinking water of 10-month-old male Sprague Dawley rats (18/treatment)
for 12 weeks. Half (9/treatment) were then killed, and the other
half were submitted to cross-over treatment for an additional 12
weeks. Twelve weeks of melatonin treatment decreased (P , 0.05)
body weight (BW; by 7% relative to controls), relative intraabdominal
adiposity (by 16%), plasma leptin (by 33%), and plasma insulin (by
25%) while increasing (P , 0.05) locomotor activity (by 19%), core
body temperature (by 0.5 C), and morning plasma corticosterone (by
154%), restoring each of these parameters toward more youthful
levels. Food intake and total body fat were not changed by melatonin
treatment. Melatonin-treated rats that were then crossed over to
control treatment for a further 12 weeks gained BW, whereas control
rats that were crossed to melatonin treatment lost BW, but food
intake did not change in either group. Feed efficiency (grams of BW
change per g cumulative food intake), a measure of metabolic function,
was negative in melatonin-treated rats and positive in control
rats before cross-over (P,0.001); this relationship was reversed after
cross-over (P , 0.001). Thus, melatonin treatment in middle age
decreased BW, intraabdominal adiposity, plasma insulin, and plasma
leptin, without altering food intake or total adiposity. These results
suggest that the decrease in endogenous melatonin with aging may
alter metabolism and physical activity, resulting in increased BW,
visceral adiposity, and associated detrimental metabolic consequences.
(Endocrinology 141: 487–497, 2000
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