The effect of daily photoperiod on the wool growth of Merino rams subjected to unrestricted and restricted feeding regimes

1964 ◽  
Vol 4 (13) ◽  
pp. 124 ◽  
Author(s):  
AJ Williams
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Seasonal Changes ◽  
Period Variation ◽  
Day Length ◽  
Growth Responses ◽  
Significant Treatment ◽  
Significant Period ◽  
Wool Growth ◽  
Daily Food

Twelve adult Merino rams were divided into two groups matched for body weight and previous fleece weights. One group was subjected to a reversed and accentuated rhythm of seasonal changes in day length. The second group received normal seasonal changes in day length (latitude 32�s). There was no temperature control for either group. For eighteen months, these rams were fed a constant ration ad lib. Daily food intakes and wool growth from a tattooed mid-side patch were recorded. Although the periodic differences in wool growth were very highly significant (P<0.001), no well defined rhythm of wool growth was expressed. There was a highly significant treatment x period interaction (P<0.001). Examination of daily food intake values revealed very highly significant period interaction ; due to a positive relation between day length and food intake during part of the eighteen months. In each treatment group, 75 per cent of the period variation in wool growth could be accounted for by variations in food intake. During a further period of fifteen months, when all rams received the same quantity of a constant diet, there was a progressive loss of body weight which amounted to 18 per cent of the initial weight in each group. The wool growth responses of the two groups were similar, and there was no significant interaction term. The very highly significant period variation in wool growth was confined largely to the first three months following the decreased intake. It appears that temperature and day length have little direct effort on wool growth of Merino sheep. However, day length may influence wool growth indirectly through its effect on voluntary food intake.

Growth in sheep. II. Efficiency of energy and nitrogen utilization from birth to 2 years

1972 ◽  
Vol 79 (3) ◽  
pp. 383-389 ◽  
Author(s):  
N. McC. Graham ◽  
T. W. Searle
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Metabolizable Energy ◽  
Wool Growth ◽  
Daily Food ◽  
Restricted Group ◽  
Ad Libitum ◽  
Energy Gains ◽  
Age Range ◽  
Milk Feeding

SUMMARYThirty sheep were pen-fed from age 2 days to nearly 2 years. Fifteen were fed ad libitum and the others were restricted to half that rate, age for age; daily food intakes were recorded. Sequential estimates of body composition were made on each sheep so that protein and energy gains could be obtained for specified age ranges.In the sheep fed ad libitum, food intake increased several fold in the first few months of life but was relatively constant from 4 months despite large increases in body weight. Thus intake per kg¾ declined progressively as the sheep grew.The data for the well fed and restricted groups were combined within each age range and linear regression was used to relate body growth (protein and energy) to food intake, variates being expressed as multiples of body weight (kg¾). Energy gain was zero when intake was 250–590 kJ metabolizable energy/day kg¾, depending on age. Wool growth per unit food intake was constant for each sheep throughout the experiment but was twice as great in some sheep as in others and was higher in the restricted group.Efficiency of energy and protein utilization declined at weaning but otherwise did not vary much with stage of growth. Approximately 40% of energy storage was in protein during milk feeding; after weaning, the fraction declined from 25 to 10% (30 to 20% including wool protein) as the sheep grew.

Regulation of metabolic rate in Svalbard and Norwegian reindeer

1984 ◽  
Vol 247 (5) ◽  
pp. R837-R841 ◽  
Author(s):  
K. J. Nilssen ◽  
J. A. Sundsfjord ◽  
A. S. Blix
Keyword(s):  
Body Weight ◽  
Critical Temperature ◽  
Food Intake ◽  
Metabolic Rate ◽  
Seasonal Changes ◽  
Serum Levels ◽  
Physiological Adaptation ◽  
Conservation Of Energy ◽  
Winter Food ◽  
Lower Critical Temperature

Food intake, body weight, serum levels of triiodothyronine (T3) and free thyroxine (FT4), and metabolic rate were measured at intervals in Svalbard (SR) and Norwegian (NR) reindeer. From summer to winter food intake decreased 57 (SR) and 55% (NR), while body weight decreased 8.6 (SR) and 3.8% (NR). In SR T3 and FT4 changed seasonally, whereas this was only evident for T3 in NR. Resting (standing) metabolic rate (RMR) in winter was 1.55 (SR) and 2.05 W X kg-1 (NR), lower critical temperature (TLC) being -50 (SR) and -30 degrees C (NR). RMR in summer was 2.15 (SR) and 2.95 W X kg-1 (NR), TLC being -15 (SR) and 0 degrees C (NR). Seasonal changes in T3 and FT4 did not coincide with changes in food intake or RMR in either SR or NR. RMR did, however, correlate with food intake. This indicates that seasonal changes in RMR are due to the thermic effects of feeding and represent no physiological adaptation aimed at conservation of energy during winter.

Chronic treatment with long-acting bromocriptine does not affect duration of the breeding season, voluntary food intake, body weight, or wool growth in the Scottish blackface ewe

1991 ◽  
Vol 3 (1) ◽  
pp. 25 ◽  
Author(s):  
JD Curlewis ◽  
AM Sibbald ◽  
JA Milne ◽  
AS McNeilly
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Chronic Treatment ◽  
Vehicle Group ◽  
Plasma Prolactin ◽  
Wool Growth ◽  
Long Acting ◽  
Group B ◽  
Group D ◽  
Voluntary Food Intake

The aim of this study was to determine whether suppression of the seasonal increase in prolactin concentrations by chronic treatment with the dopamine agonist bromocriptine would affect onset of anoestrus, voluntary food intake, body weight, and wool growth in a seasonal breed of sheep. Groups of eight Scottish Blackface ewes were injected i.m. each week with either the vehicle (Group A) or 2.0 mg (Group B), 6.0 mg (Group C), or 18.0 mg (Group D) of bromocriptine in a long-acting formulation, commencing on 18 January and terminating on 25 July (midwinter to midsummer in the northern hemisphere). Immediately before the bromocriptine injection, blood samples were taken for progesterone and prolactin determination. Voluntary food intakes were measured daily, and body weights were recorded every fortnight. Estimates of wool growth were made by weighing wool clipped from a measured area of skin once a month. Treatment had no effect on onset of anoestrus, voluntary food intake, body weight, or wool growth. Plasma prolactin concentrations increased significantly in all groups during the treatment period. From January to April, all doses of bromocriptine significantly reduced prolactin concentrations but later in the study (May and June) prolactin was significantly suppressed in Group D only, although even in this group prolactin concentrations increased between March and June. Pituitary prolactin content, measured at the end of the study in July, was also suppressed by bromocriptine. The gradual increase in prolactin concentrations in ewes receiving chronic bromocriptine was further investigated by treating a fifth group of ewes (Group E) with 18.0 mg of long-acting bromocriptine each week, commencing on 20 June.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of intermittent intraperitoneal infusion of salmon calcitonin on food intake and adiposity in obese rats

2007 ◽  
Vol 293 (5) ◽  
pp. R1798-R1808 ◽  
Author(s):  
Prasanth K. Chelikani ◽  
Alvin C. Haver ◽  
Roger D. Reidelberger
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Salmon Calcitonin ◽  
Chronic Administration ◽  
Inhibitory Effect ◽  
Free Access ◽  
Daily Food Intake ◽  
Intraperitoneal Infusion ◽  
Daily Food ◽  
Obese Rats

Chronic administration of anorexigenic substances to experimental animals by injections or continuous infusion typically produces no effect or a transient reduction in daily food intake and body weight. Our aim was to identify an intermittent dosing strategy for intraperitoneal infusion of salmon calcitonin (sCT), a homolog of amylin that produces a sustained 25–35% reduction in daily food intake and adiposity in diet-induced obese rats. Rats (649 ± 10 g body wt, 27 ± 1% body fat), with intraperitoneal catheters tethered to infusion swivels, had free access to a 45% fat diet. Food intake, body weight, and adiposity during the 7-wk test period were relatively stable in the vehicle-treated rats ( n = 16). None of 10 sCT dosing regimens administered in succession to a second group of rats ( n = 18) produced a sustained 25–35% reduction in daily food intake for >5 days, although body weight and adiposity were reduced by 9% (587 ± 12 vs. 651 ± 14 g) and 22% (20.6 ± 1.2 vs. 26.5 ± 1.1%), respectively, across the 7-wk period. The declining inhibitory effect of sCT on daily food intake with the 6-h interinfusion interval appeared to be due in part to an increase in food intake between infusions. The declining inhibitory effect of sCT on daily food intake with the 2- to 3-h interinfusion interval suggested possible receptor downregulation and tolerance to frequent sCT administration; however, food intake increased dramatically when sCT was discontinued for 1 day after apparent loss of treatment efficacy. Together, these results demonstrate the activation of a potent homeostatic response to increase food intake when sCT reduces food intake and energy reserves in diet-induced obese rats.

Intermittent intraperitoneal infusion of peptide YY(3-36) reduces daily food intake and adiposity in obese rats

2007 ◽  
Vol 293 (1) ◽  
pp. R39-R46 ◽  
Author(s):  
Prasanth K. Chelikani ◽  
Alvin C. Haver ◽  
Roger D. Reidelberger
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Peptide Yy ◽  
Caloric Intake ◽  
Daily Food Intake ◽  
Daily Caloric Intake ◽  
Intraperitoneal Infusion ◽  
Daily Food ◽  
Sustained Reduction ◽  
Obese Rats

Peptide YY(3-36) [PYY(3-36)] is a gut-brain peptide that decreases food intake when administered by intravenous infusion to lean and obese humans and rats. However, chronic administration of PYY(3-36) by osmotic minipump to lean and obese rodents produces only a transient reduction in daily food intake and weight gain. It has recently been shown that 1-h intravenous infusions of PYY(3-36) every other hour for 10 days produced a sustained reduction in daily food intake, body weight, and adiposity in lean rats. Here, we determined whether intermittent delivery of PYY(3-36) can produce a similar response in diet-induced obese rats. During a 21-day period, obese rats (body fat >25%) received twice daily intraperitoneal infusion of vehicle ( n = 18) or PYY(3-36) ( n = 24) during hours 1–3 and 7–9 of the dark period. Rats had free access to both a 45% fat solid diet and a 29% fat liquid diet; intakes were determined from continuous computer recording of changes in food container weights. To sustain a 15–25% reduction in daily caloric intake, the initial PYY(3-36) dose of 30 pmol·kg−1·min−1 was reduced to 10 pmol·kg−1·min−1 on day 10 and then increased to 17 pmol·kg−1·min−1 on day 13. This dosing strategy produced a sustained reduction in daily caloric intake of 11–32% and prevented body weight gain (8 ± 6 vs. 51 ± 11 g) and fat deposition (4.4 ± 7.6 vs. 41.0 ± 12.8 g). These results indicate that intermittent intraperitoneal infusion of PYY(3-36) can produce a sustained reduction in food intake and adiposity in diet-induced obese rodents consuming palatable high-fat foods.

scholarly journals Daily, intermittent intravenous infusion of peptide YY(3-36) reduces daily food intake and adiposity in rats

2006 ◽  
Vol 290 (2) ◽  
pp. R298-R305 ◽  
Author(s):  
Prasanth K. Chelikani ◽  
Alvin C. Haver ◽  
Joseph R. Reeve ◽  
David A. Keire ◽  
Roger D. Reidelberger
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Intravenous Infusion ◽  
Peptide Yy ◽  
Subcutaneous Administration ◽  
Chronic Administration ◽  
Daily Food Intake ◽  
Daily Food ◽  
Sustained Reduction ◽  
Gut Hormone

The gut hormone peptide YY(3-36) [PYY(3-36)] decreases food intake when administered by intravenous infusion to lean and obese humans and rats. Whether chronic administration of PYY(3-36) produces a sustained reduction in food intake and adiposity is the subject of intense debate. Batterham et al. (R. L. Batterham, M. A. Cowley, C. J. Small, H. Herzog, M. A. Cohen, C. L. Dakin, A. M. Wren, A. E. Brynes, M. J. Low, M. A. Ghatei, R. D. Cone, and S. R. Bloom. Nature 418: 650–654, 2002) first reported that PYY(3-36) reduces food intake and weight gain in rats when injected into the peritoneal cavity twice daily for 7 days. Numerous laboratories have failed to confirm that daily injections of PYY(3-36) decrease body weight. Continuous subcutaneous administration of PYY(3-36) by osmotic minipump has been reported to reduce daily food intake in rodents but only during the first 3–4 days of administration. Here we show the effects of different daily patterns of intravenous infusion of PYY(3-36) on food intake, body weight, and adiposity in rats tethered via infusion swivels to computer-controlled pumps. Measurement of food bowl weight recorded by computer every 20 s permitted daily assessment of the instantaneous effects of PYY(3-36) administration on food intake and meal patterns. One-hour intravenous infusions of PYY(3-36) at 30 pmol·kg−1·min−1 every other hour for 10 days produced a sustained reduction in daily food intake of ∼20% and decreased body weight and adiposity by 7 and 35%, respectively. Thus dosage pattern is critical for producing a sustained effect of PYY(3-36) on food intake and adiposity.

Changes in the food intake and body weight of protein-malnourished rats infected with Nippostrongylus brasiliensis (Nematoda)

Parasitology ◽  
1981 ◽  
Vol 82 (1) ◽  
pp. 23-38 ◽  
Author(s):  
D. W. T. Crompton ◽  
D. E. Walters ◽  
Susan Arnold
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Infected Group ◽  
Nippostrongylus Brasiliensis ◽  
Initial Weight ◽  
Daily Food Intake ◽  
Young Rats ◽  
Daily Food ◽  
Long Duration ◽  
Ad Libitum

SUMMARYThe daily food intake and related changes in body weight were measured in young rats which were fed on synthetic diets containing 1% (3 experiments), 2% (4 experiments) and 20% (1 experiment) casein respectively. Some rats were infected with Nippostrongylus brasiliensis and allowed to feed ad libitum, some remained uninfected and were allowed to feed ad libitum while others, which were matched by initial weight with rats from the infected group, remained uninfected and were given only the same amount of food as that consumed during the previous 24 h by their infected partners. No significant differences were detected between the rats before the start of the infection. Thereafter, the food intake of the infected undernourished rats was usually found to be significantly lower and the loss of body weight significantly greater than those of the uninfected rats. In infection periods of relatively long duration, the pair-fed uninfected rats did not lose as much weight as their infected partners even though their food intake (1% and 2% casein) was the same. Although the food intake, and consequently the weight, of infected rats fed on the diet containing 20% casein were significantly less than in their uninfected partners, no significant differences were observed between the weights of the infected and pair-fed rats fed on this diet.

scholarly journals Effects of different intermittent peptide YY (3-36) dosing strategies on food intake, body weight, and adiposity in diet-induced obese rats

2008 ◽  
Vol 295 (2) ◽  
pp. R449-R458 ◽  
Author(s):  
Roger D. Reidelberger ◽  
Alvin C. Haver ◽  
Prasanth K. Chelikani ◽  
James L. Buescher
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Peptide Yy ◽  
Chronic Administration ◽  
Inhibitory Effect ◽  
Free Access ◽  
Daily Food Intake ◽  
Daily Food ◽  
Obese Rats ◽  
Dosing Regimens

Chronic administration of anorexigenic substances to experimental animals by injections or continuous infusion typically produces either no effect or a transient reduction in food intake and body weight. Our aim here was to identify an intermittent dosing strategy for intraperitoneal infusion of peptide YY(3-36) [PYY(3-36)] that produces a sustained reduction in daily food intake and adiposity in diet-induced obese rats. Rats (665 ± 10 g body wt, 166 ± 7 g body fat) with intraperitoneal catheters tethered to infusion swivels had free access to a high-fat diet. Vehicle-treated rats ( n = 23) had relatively stable food intake, body weight, and adiposity during the 9-wk test period. None of 15 PYY(3-36) dosing regimens administered in succession to a second group of rats ( n = 22) produced a sustained 15–25% reduction in daily food intake for >5 days, although body weight and adiposity were reduced across the 9-wk period by 12% (594 ± 15 vs. 672 ± 15 g) and 43% (96 ± 7 vs. 169 ± 9 g), respectively. The declining inhibitory effect of PYY(3-36) on daily food intake when the interinfusion interval was ≥3 h appeared to be due in part to an increase in food intake between infusions. The declining inhibitory effect of PYY(3-36) on daily food intake when the interinfusion interval was < 3 h suggested possible receptor downregulation and tolerance to frequent PYY(3-36) administration; however, food intake significantly increased when PYY(3-36) treatments were discontinued for 1 day following apparent loss in treatment efficacies. Together, these results demonstrate the development of a potent homeostatic response to increase food intake when PYY(3-36) reduces food intake and energy reserves in diet-induced obese rats.

Increased short-term food satiation and sensitivity to cholecystokinin in neurotrophin-4 knock-in mice

2004 ◽  
Vol 287 (5) ◽  
pp. R1044-R1053 ◽  
Author(s):  
Michael M. Chi ◽  
Guoping Fan ◽  
Edward A. Fox
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Knockout Mice ◽  
Meal Frequency ◽  
Short Term ◽  
Daily Food Intake ◽  
Food Satiation ◽  
Daily Food ◽  
Solid Diet

Neurotrophin-4 (NT-4) knockout mice exhibited decreased innervation of the small intestine by vagal intraganglionic laminar endings (IGLEs) and reduced food satiation. Recent findings suggested this innervation was increased in NT-4 knock-in (NT-4KI) mice. Therefore, to further investigate the relationship between intestinal IGLEs and satiation, meal patterns were characterized using solid and liquid diets, and cholecystokinin (CCK) effects on 30-min solid diet intake were examined in NT-4KI and wild-type mice. NT-4KI mice consuming the solid diet exhibited reduced meal size, suggesting increased satiation. However, compensation occurred through increased meal frequency, maintaining daily food intake and body weight gain similar to controls. Mutants fed the liquid diet displayed a decrease in intake rate, again implying increased satiation, but meal duration increased, which led to an increase in meal size. This was compensated for by decreased meal frequency, resulting in similar daily food intake and weight gain as controls. Importantly, these alterations in NT-4KI mice were opposite, or different, from those of NT-4 knockout mice, further supporting the hypothesis that they are specific to vagal afferent signaling. CCK suppressed short-term intake in mutants and controls, but the mutants exhibited larger suppressions at lower doses, implying they were more sensitive to CCK. Moreover, devazepide prevented this suppression, indicating this increased sensitivity was mediated by CCK-1 receptors. These results suggest that the NT-4 gene knock-in, probably involving increased intestinal IGLE innervation, altered short-term feeding, in particular by enhancing satiation and sensitivity to CCK, whereas long-term control of daily intake and body weight was unaffected.

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