The effects of intradermal injections of spermidine on the growth rate of fibres and mitosis of wool follicles in Merino lambs

2002 ◽  
Vol 75 (1) ◽  
pp. 33-40 ◽  
Author(s):  
S. M. Liu ◽  
A. Murray ◽  
A. C. Schlink ◽  
G. Mata ◽  
D. G. Masters
Keyword(s):  
Growth Rate ◽  
Cell Proliferation ◽  
Cell Division ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Optimal Growth ◽  
Contralateral Side ◽  
Length Growth ◽  
Local Supply ◽  
High Doses

AbstractPolyamines (putrescine, spermidine and spermine) are required for optimal growth in all cells, and are essential for cell proliferation and growth of cultured wool follicles, with an optimal concentration of spermidine required for the fibre elongation. The effects of a local supply of exogenous spermidine on the rate of cell division in the wool follicles, the length growth rate and diameter of fibres were therefore examined in Merino lambs. Three groups of eight lambs (40 kg) were given food at 1·2 ✕ maintenance. Spermidine was injected intradermally into a small patch (3 ✕ 3 cm) on the left flank three times per day for 7 days at one of three concentrations: 1·38, 2·75 or 4·58 џmol in 0·8 ml volume. The same volume of saline was injected into the contralateral side as a control. The concentration of spermidine in the skin patch 3 h after injection on day 7 increased by proportionately 018, 0·33 or 0·41 (P < 0001) respectively. The rates of cell division in the follicle bulb 3 h after the spermidine injection were proportionately 0104, 0184 and 0·283 higher compared with the contralateral side (P = 0078 overall) for the low, medium and high doses of spermidine respectively and differed between the three doses (P < 005). The fibre length growth rate, as measured using autoradiography, was proportionately 0099, 0117 and 0156 higher than that of the contralateral side (P < 0001 overall) for the low, medium and high doses of spermidine respectively, but differences between doses were not significant (P > 005). Spermidine injection did not result in a significant change in fibre diameter during the treatment period. The ratio of fibre length growth rate to fibre diameter was increased by the injection of spermidine (P < 0001). The results suggest that injecting extra spermidine into the skin altered spermidine homeostasis in the skin, stimulated cell proliferation and resulted in increased fibre growth.

The influence of abomasal supplements of methionine on wool growth of wheat-fed sheep

1974 ◽  
Vol 25 (6) ◽  
pp. 919 ◽  
Author(s):  
PJ Reis ◽  
DA Tunks
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Blood Plasma ◽  
Fibre Diameter ◽  
Length Growth ◽  
Wool Growth ◽  
Abomasal Infusion ◽  
Mineral Mixture ◽  
In Blood Plasma

Sheep receiving a diet consisting solely of wheat (500 g/day), supplemented with a mineral mixture, were given abomasal infusions of varying amounts of DL-methionine (1.5–6.0 g/day) or of L-cystine (5 g/day). Other sheep received DL-methionine as a supplement to a roughage diet. All levels of methionine infused caused a decrease in the mass of wool grown by sheep consuming the wheat diet. This effect was greatest with 6 g methionine and was due mainly to a considerable depression of fibre diameter. Smaller amounts of methionine decreased fibre diameter and increased length growth rate. The infusion of methionine caused a considerable weakening of the wool grown by most of the sheep, with the result that a 'break' was observed in the fleece after about 1 week of methionine administration. This effect occurred with all levels of methionine but was more pronounced with 6 g/day. The abomasal infusion of cystine (5 g/day) caused little change in the mass of wool grown, but fibre diameter was decreased slightly. There were no appreciable effects on the strength of wool fibres and no wool was shed. Supplementation of the roughage diet (400 g/day) with methionine at 2 g/day stimulated wool growth, whereas with 6 or 10 g/day the mass of wool grown was unchanged but fibre diameter was markedly reduced. The strength of wool fibres was not markedly influenced by methionine infusions on this diet. The levels of amino acids in blood plasma and in abomasal digesta indicated that the mixture of amino acids absorbed was similar with both the roughage and the wheat diets.

Seasonal variation in fibre diameter and length in wool of grazing Merino sheep with low or high staple strength

1999 ◽  
Vol 39 (5) ◽  
pp. 507 ◽  
Author(s):  
A. C. Schlink ◽  
G. Mata ◽  
J. M. Lea ◽  
A. J. M. Ritchie
Keyword(s):  
Fibre Diameter ◽  
Fibre Length ◽  
Subterranean Clover ◽  
Experimental Period ◽  
Strength Group ◽  
Pooled Data ◽  
Length Growth ◽  
Fibre Growth ◽  
Staple Strength ◽  
Highly Correlated

The associations between fibre growth characteristics and wool staple strength were investigated in groups (n = 10) of Merino wethers with either low or high staple strength. Sheep grazed together on pastures based on subterranean clover and annual rye grass for about 13 months. The sheep were weighed and injected intradermally with [35 S]-cysteine at about 14-day intervals. Mid-side patches were harvested and dye bands placed in the wool at about 28-day intervals. Patch clean wool growth, pasture digestible dry matter/ha and pasture crude protein/ha had similar seasonal amplitudes of production (287, 286 and 267% of respective minimum). These were significantly higher than the seasonal amplitude in liveweight (24.5%). The seasonal amplitude in fibre diameter was significantly greater than that for rate of fibre elongation (71.4 and 41.4% respectively). This seasonality in fibre length and diameter resulted in statistically significant seasonal fluctuations in the ratio of fibre length growth to fibre diameter. Fortnightly variability in fibre diameter was not significantly related to variability in fibre length growth rate between sheep for individual time periods. However, for the pooled data over the experimental period a statistically significant relationship (R2 = 0.13, P<0.01) was improved with the addition of parameters for sampling time and staple strength group. Staple strengths for the low and high staple strength groups were 25.6 and 32.8 N/ktex respectively (P = 0.057). There were no significant differences between the staple strength groups in seasonal change in liveweight, wool production or fibre parameters measured in this study but the low staple strength group had longer fibres. Staple strength was most highly correlated with mid-side fibre diameter coefficient of variation (R2 = 0.50) followed by seasonal amplitude in liveweight.

STUDIES ON THE RELATION OF GROWTH RATE TO WOOD QUALITY IN POPULUS HYBRIDS

1942 ◽  
Vol 20c (1) ◽  
pp. 28-40 ◽  
Author(s):  
L. P. V. Johnson
Keyword(s):  
Growth Rate ◽  
Wood Quality ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Fast Growth ◽  
Annual Rings ◽  
Annual Increment ◽  
Soda Pulp ◽  
Individual Trees ◽  
Slow Growing

Experiments were conducted on the relation of growth rate to wood quality in a series of 43 hybrid and parental trees, which involved Populus alba, P. grandidentata, and P. tremuloides.Fibres in fast growth annual rings were longer on the average than those in slow growth rings from the same tree. In single annual rings, fibres of early wood were shorter and thicker than those of late wood.Average fibre diameter of individual trees was significantly correlated in a positive manner with growth rate, but the correlation between fibre length and growth rate was well below the level of significance.Short, thick habit of growth was significantly correlated with high density of wood, but correlations between growth rate (in terms of annual increment in volume) and wood density were insignificant.Experimental pulp and paper tests did not reveal any very striking differences in quality between fast growing hybrid and slow growing parental trees, although there remains some doubt as to the suitability of abnormally fast growth hybrid wood for some of the higher grades of soda pulp paper.The general, and tentative, conclusion is that the investigation revealed nothing to indicate that rapid growth is seriously detrimental to wood quality.

Environmental responsiveness of fibre diameter in grazing fine wool Merino sheep

2005 ◽  
Vol 56 (7) ◽  
pp. 673 ◽  
Author(s):  
D. J. Brown ◽  
B. J. Crook
Keyword(s):  
Seasonal Variation ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Skin Thickness ◽  
Merino Sheep ◽  
Length Growth ◽  
Environmental Responsiveness ◽  
Diameter Fibre ◽  
Staple Strength ◽  
Profile Characteristics

Fibre diameter, fibre length, and the ratio of fibre length growth to mean fibre diameter (L/D), fibre diameter profile characteristics, and staple strength were examined in 16 fine wool Merino wethers in a 12-month field experiment. Variations in fibre diameter, fibre length, and L/D were shown to be associated with fibre diameter profile characteristics and staple strength. At constant fibre diameter, L/D was significantly positively related to variation in fibre diameter along the staple. A positive correlation between seasonal variation in L/D and variation in diameter between fibres was also observed. Staple length was significantly positively correlated with along-staple variation in fibre diameter and negatively correlated with variation in fibre diameter among fibres. Among-fibre variation in fibre diameter was not significantly correlated with along-staple variation in fibre diameter. Seasonal variation in fibre length growth, fibre diameter, and the ratio of length to diameter throughout the year was associated with increased variation in fibre diameter along the fibre diameter profile and reduced staple strength in grazing sheep. Seasonal variation in fibre diameter was mostly related to mean fibre diameter, L/D, and seasonal variation in fibre length growth rate. Changes in fibre diameter throughout the year were also related to seasonal changes in body weight, fat depth, and skin thickness.

Cell proliferation in the wool follicles of fleeceweight selected and control Romney rams

1993 ◽  
Vol 44 (2) ◽  
pp. 239 ◽  
Author(s):  
KE Kelly ◽  
PM Haris ◽  
MJ Birtles ◽  
DW Dellow ◽  
AJ Hall
Keyword(s):  
Cell Proliferation ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Cell Movement ◽  
The Other ◽  
Three Dimensions ◽  
Circumflex Artery ◽  
Low Levels ◽  
And Control ◽  
Infusion Period

Two year old Romney rams from the Massey University fleeceweight-selected (FW) and control (C) lines, five from each line, were given arterial catheters into a branch of the deep circumflex artery on each side of the sheep, to permit local infusion into patches of skin on each lateral abdominal flank. One side of each sheep was infused with saline to give a direct FW v. C comparison, while the other side was infused with low levels of either growth hormone, thyroxine, prolactin or insulin for 4 days. At the end of the infusion period, biopsy samples were taken from each flank for measurement of follicle activity, particularly bulb cell proliferation using intracutaneous injections of 5-bromo-2'-deoxyuridine (BrDU). After a period of recovery, the saline and treated sides were reversed and another series of infusions were performed and biopsies undertaken. Wool from the FW sheep had greater fibre length growth rate and fibre diameter than the C wool (P < 0.05). This was associated with larger follicle bulbs (P < 0.05) and greater numbers of BrDU labelled cells (P < 0.05) in the bulbs of the FW skin. In a restricted number of samples from two sheep, where BrDU was successfully given as repeated intracutaneous injections into the same site (one at 72 h and one at 6 h prior to biopsy), 55-60% of the numbers of BrDU cells in a section of bulb appeared in a section of the shaft of the same follicle. When converted to three dimensions, the efficiency of labelled bulb cell movement into the shaft was 30-40%. Hormonal infusions showed few significant effects with the restricted numbers of animals in each treatment. Thyroxine reduced the size of follicle bulbs (P <0.05) and the numbers of labelled bulb cells in skin from the infused area.

Effects of shearing time and time of lambing on wool growth and processing characteristics

1984 ◽  
Vol 24 (126) ◽  
pp. 337 ◽  
Author(s):  
GW Arnold ◽  
AJ Charlick ◽  
JR Eley
Keyword(s):  
Growth Rate ◽  
Seasonal Pattern ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Lower Percentage ◽  
Dominant Factor ◽  
Lower Yield ◽  
Merino Sheep ◽  
Wool Growth ◽  
Fleece Weight

Wool growth rate, seasonal pattern of fibre diameter, clean fleece weight, quality and the processing characteristics of wool were measured on medium-wool Merino sheep shorn in March (autumn) or October (spring) coupled with March or June lambing. These four management systems were compared under two nutritional regimes in the medium rainfall area of Western Australia. The sheep grazed annual pastures only, or had lupin grain and stubble during summer in addition to the pasture. The study ran for two shearing periods. Time of shearing was the dominant factor. Sheep shorn in March produced 14% more clean wool and fewer tender fleeces than sheep shorn in October. The autumn wool had a lower yield, higher fibre diameter and when processed had a higher card loss, lower percentage noil and lower top and noil yield. However, mean fibre length in the top was substantially higher and the variation in fibre length lower. Vegetable matter was higher in autumn shorn wools. There were some interacting effects of lambing time and type of feed regime. Sheep fed lupins had lower yielding wool but this effect was more pronounced in June lambings and was reflected in differences in top and noil yield. From measurements of wool growth rate, it was found that the extra wool was produced in autumn after shearing, due possibly to stimulated appetite that cannot occur after spring shearing because the sheep are too fat.

Intake and long-term cysteine supplementation change wool characteristics of Romney sheep

2001 ◽  
Vol 52 (1) ◽  
pp. 29 ◽  
Author(s):  
R. G. Sherlock ◽  
P. M. Harris ◽  
J. Lee ◽  
G. A. Wickham ◽  
J. L. Woods ◽  
...  
Keyword(s):  
Growth Rate ◽  
Treatment Period ◽  
Fibre Diameter ◽  
Wool Fibre ◽  
Amino Acid Supplementation ◽  
Sulfur Concentration ◽  
Treatment Groups ◽  
Length Growth ◽  
Wool Growth ◽  
Pre Treatment

Sulfur amino acid supplementation increases wool production in sheep at low planes of nutrition but it is unclear whether there is any benefit of supplementation at planes of nutrition above maintenance and what implications this might have for wool quality characteristics. This experiment directly investigated the interaction between sulfur supplementation and plane of nutrition in terms of wool growth and fibre characteristics. Twenty-four Romney ewes, acclimatised in individual metabolism units over a 7-week pre-treatment period, were allocated to 1 of 4 treatment groups based on a 22 factorial arrangement. Groups were low (L) or high (H) intake (0.8 or 1.3 maintenance, respectively) with continuous intravenous infusion of either saline (–Cys) or cysteine (+Cys, 2 g/day). During the 3-month treatment period, measurements were obtained for liveweight, plasma cysteine concentration, wool sulfur concentration and output, clean wool growth, mean fibre diameter (MFD), length growth rate (LGR), colour, loose wool bulk, handle, and crimp frequency and character. Clean wool growth response (P < 0.05) to cysteine supplementation was greater for the L sheep (6.06 v. 4.31 g/100 cm2) than the H sheep (7.20 v. 6.13 g/100 cm2). The response to supplementation in LGR (P < 0.01) was similar in both H (14%) and L (20%) sheep. There was no response in MFD due to sulfur supplementation, although fibre diameter measurements made along the fibres suggest that there was a response in L but not H sheep (P < 0.1). Wool sulfur concentration and output increased as a result of cysteine supplementation but concentration increased more in L (30.6 v. 24.5 mg S/g; P < 0.01) than in H sheep (28.4 v. 26.2 mg S/g). Qualitative electrophoresis analyses suggested that the increase in wool sulfur was achieved primarily by an increase in ultra-high-sulfur proteins. Crimp frequency and character were both significantly (P < 0.01) enhanced by cysteine supplementation. It is concluded that cysteine supplementation, at feed intakes that commonly occur in the commercial situation, can produce a useful increase in wool growth. This growth increase is primarily accomplished by increasing length growth rate rather than fibre diameter, which should also improve the value of the wool fibre produced.

A study of some wool traits in two coarse wool breeds and their reciprocal crosses

1978 ◽  
Vol 90 (3) ◽  
pp. 495-501 ◽  
Author(s):  
R. A. Guirgis ◽  
N. T. Kazzal ◽  
M. S. Haddadine ◽  
R. K. Abdallah
Keyword(s):  
Growth Rate ◽  
Environmental Factors ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Bimodal Distribution ◽  
The Other ◽  
Maternal Influence ◽  
Reciprocal Crosses ◽  
Diameter Fibre ◽  
The Mean

SummaryIn a study of two coarse wool breeds (Awassi and Karadi) and their reciprocal crosses, data were obtained on the mean fibre length, mean fibre diameter, fibre type ratio, medullation and on the effect of some environmental factors on these traits. Reciprocal crosses showed intermediate values, in growth rate of fibres, percentages of fibre types and medullation, between those of the parental breeds. Sex exhibited a significant effect at weaning only, on fibre length. Heterosis in fibre length, at the two ages, was small and negative. Maternal influence on fibre length was small and not significant. Fibre length in Karadi sheep showed the highest frequency of bimodal distribution whereas Awassi showed the lowest. Awassi × Karadi was closer to Karadi and Karadi × Awassi had greater affinity to Awassi in the frequency of samples showing bimodal distribution.Reciprocal crosses had larger diameter, at weaning, than those of the parental breeds. At 1 year of age they assumed an intermediate position between the pure bred parents.At weaning, the two reciprocal crosses showed a highly significant heterosis in fibre diameter; its value decreased with advancing age and it showed no significant effect at 1 year of age.Maternal influence on fibre diameter was very small and not significant.Karadi × Awassi and Karadi samples had the highest percentage of samples showing bimodal distribution of fibre diameter.Samples with bimodal distribution of both length and diameter, indicating two coats, had the highest frequency in Karadi followed by Karadi × Awassi; Awassi showed the lowest value.Percentages of fine, coarse and kemp fibres were significantly affected by breed and age of dam. Type of birth showed a significant effect only on percentage of coarse fibres.Karadi wool might be more suitable for carpet manufacturing. It excelled the other groups in the bimodal distribution of both length and diameter as well as in medullation. Cross-breeding increased the bimodality of fibre distribution.

The influence of abomasal supplements of zein and some amino acids on wool growth rate and plasma amino acids

1976 ◽  
Vol 86 (3) ◽  
pp. 475-482 ◽  
Author(s):  
P. J. Reis ◽  
D. A. Tunks
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Volume Growth ◽  
Fibre Diameter ◽  
Essential Amino Acids ◽  
Fibre Volume ◽  
Plasma Amino Acids ◽  
Leucine Supplementation ◽  
Length Growth ◽  
Wool Growth

SummaryMerino sheep were given abomasal infusions of (i) zein (80 g/day), (ii) zein (80 g/day) supplemented with L-lysine (6 g/day), L-tryptophan (1 g/day) or lysine and tryptophan together, or (iii) L-leucine (20 g/day). Effects on wool growth (length growth rate, fibre diameter, fibre volume growth rate and mass of wool grown) and on plasma amino acids were measured.Zein increased length growth rate and decreased fibre diameter; on average the volume growth rate and mass of wool grown were not significantly altered. The addition of tryptophan to the infusion of zein did not significantly alter wool growth, whereas the addition of lysine significantly increased all aspects of wool growth. The responses to these treatments were rapid and were adequately assessed during 12-day infusion periods. The infusion of leucine did not cause any appreciable changes in wool growth.Leucine supplementation increased the concentration of leucine in blood plasma about six-fold. Zein decreased the concentration of lysine and ornithine in plasma and increased the concentration of several essential amino acids; leucine was increased about seven-fold. The addition of tryptophan to zein had no effects on plasma amino acids, whereas lysine decreased the concentration of several amino acids in plasma and markedly increased lysine.

Effects of experimentally produced local subdermal temperature changes on skin temperature and wool growth in the sheep

1970 ◽  
Vol 74 (1) ◽  
pp. 83-90 ◽  
Author(s):  
A. G. Lyne ◽  
M. Jolly ◽  
D. E. Hollis
Keyword(s):  
Growth Rate ◽  
Fibre Diameter ◽  
Slight Reduction ◽  
Environmental Disturbances ◽  
Temperature Changes ◽  
Merino Sheep ◽  
Cooling Period ◽  
Length Growth ◽  
Wool Growth ◽  
Change In Mean

SUMMARYA heat-exchange chamber made of perspex was inserted beneath the skin of a Merino sheep. By passing water at predetermined temperatures through the chamber, the normal subdermal temperature of 37°C was raised approximately 4°C for 4 days, then lowered approximately 5°C for 4 days.In response to heating, the animal's temperature regulating mechanism was able to maintain a fairly constant subdermal temperature. However, it was unable to maintain as constant a subdermal temperature in response to cooling. There was, during the cooling period, an obvious nervous response to environmental disturbances manifested by sudden transient decreases in subdermal temperature over the chamber.During the cooling period there was a decrease of 12% in mean length growth rate of wool over the chamber but mean fibre diameter was unchanged. Heating produced a small decrease in mean fibre diameter, but no change in mean length growth rate. Heating appeared to produce a slight reduction in pigmentation of some fibres but neither heating nor cooling produced demonstrable changes in crimping.

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