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Keratinase is capable of distinctive degradation of keratin, which provides an eco-friendly approach for keratin waste management towards sustainable development. In this study, the recombinant keratinase (KERBP) from Brevibacillus parabrevis was successfully expressed in Escherichia coli. The purified KERBP had the specific activity of 6005.3 U/mg. It showed remarkable tolerance to various surfactants and also no collagenolytic activity. However, the moderate thermal stability limited its further application. Thus, protein engineering was further adopted to improve its stability. The variants of T218S, S236C and N181D were constructed by site-directed mutagenesis and combinatorial mutagenesis. Compared with the wild type, the t 1/2 at 60 °C for the variants T218S, S236C and N181D were 3.05-, 1.18- and 1-fold increase, respectively. Moreover, the double variants N181D-T218S and N181D-S236C significantly improved thermostability with 5.1 and 2.9 °C increase of T 50 , and prolonging t 1/2 at 60 °C with 4.09 and 1.54-fold, respectively. And the catalytic efficiency of the T218S and N181D-T218S variants was also significantly improved. Furthermore, the keratinase displayed favorable ability to dehair wool from skin within 7 h, which showed potential in leather dehairing. Our work contributes to a further insight into the thermostability of keratinase and offers a promising alternative for industrial leather application., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The focus of this work is to extract a natural dye for colouring camel wool as a substitute for synthetic dyes used in the Sadu House of Kuwait. Their target is to keep the tradition of tent and rug production natural in all its manifestations. Therefore, our task was to find an abundant source that provides a colour preferably red to purple. Hibiscus rosa sinensis (HRS) is an abundantly available plant in Kuwait that was explored for extraction of the red dye to colour camel wool permanently. The powdered petals of red flowers of HRS was extracted with 5% acetic acid which yielded a deep red colour that showed a great potential for woollen fibre dyeing. The use of mordants like alum and some metal salts manifested a wide range of fixed colours which intensified at 85 °C. The colours produced had excellent fastness and was accepted by the Sadu House.

The correlations between growth and wool traits in response to canola and flaxseed oil supplementation were evaluated in Australian prime lambs. Sixty dual-purpose prime lambs including purebred Merino and crossbred lambs were allocated to one of five treatments of lucerne hay basal diet supplemented with isocaloric and isonitrogenous wheat-based pellets. Treatments were: no oil inclusion (Control); 2.5% canola oil; 5% canola oil; 2.5% flaxseed oil and 5% flaxseed oil, with lamb groups balanced by breed and gender. Each lamb was daily supplemented with 1kg of pellets and had free access to lucerne hay and water throughout the 7-week feeding trial, after a 3-week adaptation. Individual animal basal and supplementary pellet feed intakes were recorded daily, while body conformation traits, body condition scores and liveweights were measured on days 0, 21, 35 and 49. The lambs were dye-banded on the mid-side and shorn before commencing the feeding trial and mid-side wool samples were collected from the same dye-banded area of each lamb at the end of the experiment. Correlations between wool quality traits and lamb performance were non-significant (P>0.05). Oil supplementation had no detrimental effect on lamb growth and wool quality traits (P > 0.05). Gender significantly affected wither height gain and fibre diameter. There were significant interactions between oil supplementation and lamb breed on chest girth. The correlations between clean fleece yield (CFY) and other wool quality traits were moderate ranging from 0.29 to 0.55. Moderate to high correlations between fibre diameter (FD) and other wool quality traits were detected (0.46-0.99) with the strongest relationship between FD and wool spinning fineness (SF). The relationship between CFY and wool comfort factor (CF) were positive, while negative relationships between CFY and the others were observed. A combination of 5% oil supplementation and genetics is an effective and strategic management tool for enhancing feed efficiency and growth performance without negative effects on wool quality in dual-purpose lamb production. This is a good outcome for dual-purpose sheep farmers. It essentially means the absorbed nutrients in supplemented lambs yielded good growth performance without any detrimental impact on wool quality; a win-win case of nutrient partitioning into the synthesis of muscle and wool without compromising either traits., Competing Interests: The authors have declared that no competing interests exist.

The keratin macromolecule in wool fiber may be found in α-helix or β-sheet conformations besides a disordered portion. The physical and chemical treatments may cause transformations between α-helix and β-sheet conformations. The aim of this study was to investigate the influence of lecithin treatment on the wool fiber using the micro-Raman spectroscopy and Fourier transform infrared spectroscopy. Characteristic bands found in the FTIR spectra of wool fibers including the amide A, amide B and amide I-III, which are assigned to the peptide bonds of wool keratin and arise from the amide bonds that link the amino acids. The lecithin treatment didn't affect the peak position of amide bands and only slightly influenced their intensity. It means that the lecithin treatment didn't change the chemical structure of wool fibers. The amide I and III regions, CC skeletal vibration region, and SS bonds vibration regions were analyzed with the Raman microscope. The results indicated the peak area of α-conformation increased gradually by lecithin treatment of the wool fiber, while the peak area of β-conformation decreased. Therefore, it seems that lecithin treatment of the wool fiber resulted in transformation of β-sheet to α-helix., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Novel naphthalimide-poly(amidoamine) dendrimer fluorescent dyes were synthesized, and their structures were identified and confirmed using different characterization methods such as Fourier transform infrared, (1) H NMR, (13) C NMR, differential scanning calorimetry, elemental analysis and UV-vis spectroscopy. The spectrophotometric studies demonstrated absorption maxima (λmax ) and extinction coefficient (εmax ) values in the ranges of 429-438 nm and 25,635-88,618 L/mol/cm, respectively. The dyeing, fastness and antimicrobial properties of dyed wool fibers were examined. Colorimetric measurements demonstrated a greenish-yellow hue with remarkable fluorescence intensity on dyed wool. Although the fastness properties of naphthalimide dye on wool fibers were poor/moderate, color fastness was appreciably improved through modification of the dye using dendrimers. The results revealed that the newly synthesized dyes are potent antimicrobial agents on wool fibers. Overall, it was deduced that poly(amidoamine) (PAMAM) dendrimers could be exploited as a promising tool in tailoring the different properties of naphthalimide dyes, being suitable for dyeing and antimicrobial finishing agents for wool fibers. Copyright © 2015 John Wiley & Sons, Ltd., (Copyright © 2015 John Wiley & Sons, Ltd.)

Biocompatible keratin-based hydrogels prepared by electron beam irradiation (EBI) were examined in wound healing. As the EBI dose increased to 60 kGy, the tensile strength of the hydrogels increased, while the percentage of elongation of the hydrogels decreased. After 7 days, the dehydrated wool-based hydrogels show the highest mechanical properties (the % elongation of 1341 and the tensile strength of 6030 g/cm(2) at an EBI dose of 30 kGy). Excision wound models were used to evaluate the effects of human hair-based hydrogels and wool-based hydrogels on various phases of healing. On post-wounding days 7 and 14, wounds treated with either human hair-based or wool-based hydrogels were greatly reduced in size compared to wounds that received other treatments, although the hydrocolloid wound dressing-treated wound also showed a pronounced reduction in size compared to an open wound as measured by a histological assay. On the 14th postoperative day, the cellular appearances were similar in the hydrocolloid wound dressing and wool-based hydrogel-treated wounds, and collagen fibers were substituted with fibroblasts and mixed with fibroblasts in the dermis. Furthermore, the wound treated with a human hair-based hydrogel showed almost complete epithelial regeneration, with the maturation of immature connective tissue and hair follicles and formation of a sebaceous gland., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Silver nanoparticles are being used increasingly in various applications because of their antibacterial properties. It is necessary to lower their direct contact with the skin by embedding in a polymer reducing their side effects. In this study, silver nanoparticles were synthesized inside the wool fibers acted as a polyfunctional ligands. Lecithin as a biological lipid was used to enhance the diffusion of silver ions and nanoparticles into the wool fibers reducing cytotoxicity effects of the nano silver loaded wool. The highest loading efficiency and inhibition zone was observed on the wool with the highest lecithin concentration. Presence of lecithin reduced the rate of nano silver release which results in decreasing the specific coefficient of lethality. Also, the extracted solution of the synthesized silver nanoparticles on the wool has not altered the morphology of L929 fibroblast cells., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Trans-glutaminases is known as a cross-linking enzyme for proteins. Wool is a proteinous fiber conventionally is treated through several processes to obtain the desirable characteristics. Bleaching is also one of the most important processes usually carried out by using an oxidizing agent in a conventional method. The tensile strength of wool yarns was reduced as a consequence of oxidative bleaching. Here, with the help of microbial trans-glutaminases (m-TGases), a novel bleaching process was disclosed in a way to obtain a bleached wool yarn with no significant reduction in the tensile strength. The results confirmed that the bleached wool yarns with H(2)O(2) could be modified by m-TGases post-treatment. The m-TGases treatment on the bleached wool yarns improved the tensile strength and whiteness along with the higher alkali resistance.

In this study an effective nanocomposite antimicrobial agent for wool fabric was introduced. The silver loaded nano TiO(2) as a nanocomposite was prepared through UV irradiation in an ultrasonic bath. The nanocomposite was stabilized on the wool fabric surface by using citric acid as a friendly cross-linking agent. The treated wool fabrics indicated an antimicrobial activity against both Staphylococcus aureus and Escherichia coli bacteria. Increasing the concentration of Ag/TiO(2) nanocomposite led to an improvement in antibacterial activities of the treated fabrics. Also increasing the amount of citric acid improved the adsorption of Ag/TiO(2) on the wool fabric surface leading to enhance antibacterial activity. The EDS spectrum, SEM images, and XRD patterns was studied to confirm the presence of existence of nanocomposite on the fabric surface. The role of both cross-linking agent and nanocomposite concentrations on the results was investigated using response surface methodology (RSM)., (2011 Elsevier B.V. All rights reserved.)

This research has explored the effect of laccase (Denilite II S) on the physical properties of the wool fabric and confirms the anti-felting of wool. In the experiment, laccase was applied to a wool fabric and different characteristics including weight loss, strength, alkali solubility, felting shrinkage, water drop absorption, and dye ability with madder were studied. The surface morphology of the wool fabrics was also observed by scanning electron microscope. The results indicated that the wool fabric treated with laccase has a higher water drop absorption, lower felting shrinkage, and lower values of a* and b*. Treatment of a wool fabric with 10% or lower percentage of laccase reduced the fabric weight but increased the tensile strength. However, using higher concentration of laccase reduced fabric weight and tensile strength. The dyeing of laccase pre-treated wool fabric with madder indicated a lower lightness.

In this study ultrasonic energy is applied for improving wet wool chlorination treatment one of the most well-established methods for reducing wool shrinking related to the felting. Sodium hypochlorite used for providing active chlorine in chlorination bath and samples chlorinated in the presence and absence of ultrasonic irradiation with equal processing parameters. The concentration of active chlorine during the treatment, shrinkage percentage, friction and some mechanical properties of treated samples determined and compared. Scanning Electron Microscope used for investigating the effects of different treatments on removal of wool scales. According to the results it was concluded that applying ultrasonic energy causes desirable mechanical and chemical effects in chlorination process. Cavitation phenomena causes more abrasion on wool surface especially on sharp places i.e., scales and the formation of hydrogen peroxide in ultrasonic bath managing the aggressive reaction of active chlorine on cuticle.

To evaluate the prophylactic and therapeutic effects of an ivermectin controlled-release capsule (IVM-CRC) on the productivity of growing sheep infested with Psoroptes ovis 24 male and 24 female Merino landrace lambs, 5-6 months old and weighing 21.2-35.0 kg, were used. Sixteen replicates of three animals were formed based on sex and Day 0 body weight. Within each replicate animals were randomly allocated to one of three groups: untreated control; IVM-CRC on Day 0; IVM-CRC on Day 84. For treatment an IVM-CRC for sheep weighing 20-45 kg was used which is designed to deliver ivermectin at a minimum dose of 20 microg/kg/day for 100 days. The lambs were infested with 50-60 P. ovis mites each on days 14 and 21. The animals were shorn on Day 126. After slaughter on Day 127 the quality of the leather produced from their skins was evaluated. The IVM-CRC treatment on Day 0 prevented the establishment of P. ovis. All untreated lambs became infested. The lambs treated with an IVM-CRC on Day 84 became mite-free from Day 112 onwards. The lambs which were treated on Day 0 had significantly (p<0.05) greater clean fleece weight (1.5 kg) and fleece yield (52.1%) than the untreated controls (0.9 kg and 34.1%, respectively) or than lambs treated on Day 84 (1.0 kg and 47.8%, respectively). Clean fleece weight and fleece yield were in the tendency (p=0.055) or significantly (p<0. 001) greater, respectively, for lambs treated on Day 84 than for the untreated controls. The chrome tanned dried crust leather of all untreated controls and six of the 16 lambs treated on Day 84 showed grain surface defects such as discolourations, indurations and coarse, pitted grain. The useful (defect-free) leather size was significantly (p<0.01) higher for the lambs treated on Day 0 (100%) than for the lambs treated on Day 84 (82.7%) and the untreated controls (7.8%). The physical testing revealed that the leather of sheep treated on Day 0 had significantly (p<0.05) higher thickness, elongation break and tear resistance than the leather of both untreated controls and sheep treated on Day 84. There were no significant differences in the physical characteristics of the leather of the untreated controls and the sheep treated on Day 84.

Methionine (Met) is usually the first limiting amino acid for sheep and supplements of Met may increase production of wool and meat. The wool response may be due to an increased supply of cysteine (Cys) from transsulfuration (TS) of Met. Met is catabolized through homocysteine to form Cys when the S from Met is transferred to serine (Ser). We hypothesized that providing additional Met would create a deficiency of Ser and that by simultaneously providing Met and Ser, TS and wool growth could be increased more than by providing Met alone. The effects of i.v. infusions of Met and Ser to young Merino lambs on TS, fractional synthesis rate (FSR) of protein in skin, follicle mRNA and wool growth were examined. Following 4 d of constant i.v. infusion of 3 g Met/d, or 10 g Ser/d or both, the isotope tracers: L-[3-(13)C]Cys, L-[ring-d5]phenylalanine (Phe) and L-[2,3,3-d3]Ser were infused over 8 h to allow for measurements of irreversible loss rate (ILR), and TS in whole body and skin. Skin biopsies were taken for measurement of FSR. Wool growth rate was measured using autoradiography. An infusion of Met significantly (P < 0.05) improved wool growth rate and increased skin FSR, Cys supply from TS and enhanced levels of follicle mRNA (from the K2.10 intermediate filament gene and three gene families encoding keratin associated proteins KAP1, KAP4 and KAP12). The extra Met lowered Ser ILR. The infusion of Ser doubled Ser ILR in the body and increased skin FSR calculated using the Cys tracer in plasma (P < 0.05). However, there were no significant (P > 0.05) changes in TS, skin FSR calculated using the Phe and Ser tracers, follicle mRNA or wool growth rate as a result of Ser infusion. While there were trends towards increased TS and FSR with Ser infusion, the overall lack of significant changes indicates a high capacity for the de novo synthesis of Ser.

Fourteen Angora does (35+/-2 kg), each with a single kid and in the first month of lactation, were used to determine ongoing (Period 1) and residual (Period 2) effects of chronic bovine somatotropin (bST) treatment. Specifically, we sought to determine whether chronic bST treatment was capable of improving milk yield, and thus kid growth, and mohair production of nursing does. The experiment consisted of a 2-wk pretreatment period, 5 wk of weekly subcutaneous treatment of slow-release bST (n = 7; Period 1), and a 4-wk posttreatment period (Period 2). The weekly dose of bST was calculated to release 100 microg/(kg BW.d(-1)). To estimate milk production, kids were separated from the does daily for 5 h, and their BW was recorded before and after suckling. The difference in BW was taken as milk production for 5 h. Fiber growth was measured by shearing does at the start of the experiment and at the end of Periods 1 and 2. Dry matter intake and BW of does were not affected by bST (P>.05). Average daily gain of kids that were suckling bST-treated does was higher (P<.05) than for kids of untreated does during Period 1 (184 vs. 139 g/d) but not during Period 2 (140 vs. 136 g/d; P>.10). Treatment with bST did not affect (P>.10) milk composition or clean fleece production in either period. Injection of bST did not affect (P>.10) plasma concentrations of glucose (mean = 49.5 mg/dL), urea N (mean = 19 mg/dL), total protein (mean = 72.5 g/d), or NEFA (mean = 122 microEq/L). During the period of bST treatment, plasma concentrations of somatotropin and IGF-I were increased (P<.05), concentrations of thyroxine and cortisol were decreased (P<.10), and plasma insulin levels were unchanged (P>.10) by bST. In conclusion, treatment of Angora dams with bST did not change DMI or mohair growth, but it improved growth of their kids.

The effects of fibroblast growth factor-1 (FGF-1) and FGF-2 on fibre growth and follicle function were examined using a previously described procedure to culture wool follicles. Because the FGFs bind to glycosaminoglycan components of the extra-cellular matrix, we also investigated interactions between FGF-1 and FGF-2 with heparin on wool fibre growth. Individual follicles were microdissected from Merino sheepskin and transferred to culture. Follicles increased in length for 6 days, and in all groups, no significant differences in follicle length were observed. Increase in follicle length was associated with fibre growth, follicles maintained normal anagen morphology and incorporated [3H]thymidine into the bulb and outer root sheath cells. Follicles in all treatments continued to produce fibre keratins, as detected by immunohistochemistry. However, the patterns of fibre and cytoskeletal proteins incorporating [35S]methionine in control and treated follicles were significantly different. We found a considerable decrease in the intermediate filament keratins or low sulphur proteins in follicles cultured in the presence of FGF-1 and FGF-2 compared to controls. The majority of proteins detected in these samples were acidic high sulphur proteins. These studies provide evidence for a specific role for the fibroblast growth factors in the regulation of fibre differentiation.

A serum-free culture system allowed the continued growth of fibre from follicles for 8-10 days. Fibre growth was responsive to changes in the level of calcium, glucose and amino acids in the culture medium, and was stimulated by the inclusion of insulin (10 micrograms/mL) in the medium. Culture of follicles in the presence of conditioned media from dermal papilla cells or of mitomycin-treated dermal papilla cells had no effect on fibre growth. Neither thyroid hormones nor hydrocortisone altered fibre growth. The progressive decline in fibre growth during follicle culture was accompanied by morphological changes in the follicle bulb. Oxidative damage did not appear to be the cause of these changes as there was no increase in fibre growth rate or longevity when antioxidants were used. This model provides a useful system to study the direct effects of various hormonal, nutritional and growth factors of fibre growth and follicle metabolism.

Adult sheep were administered 12 mg thiocyanate (SCN-)/kg body weight orally twice a year in altogether 16 respectively 41 single doses under conventional keeping during the period of stabling (winter) in two consecutive years. Fattening lambs got an analogous SCN- dosage with altogether 4 respectively 34 single doses under intensive keeping. Aided by this temporarily obtained balance of an alimentary SCN- deficiency the following effects were reached during conventional keeping: Significant increase of the wool mass in the greasy state and a tendency to better breading performance. During intensive fattening an increase of the wool mass and of the staple cross-section was proven statistically in the mean for all the test animals, but for the increase of the staple length it could be shown only by comparison of twins.

The development of a procedure to culture wool follicles from Merino sheep in serum-free conditions has enabled us to investigate the actions of epidermal growth factor (EGF) and transforming growth factor alpha (TGF alpha) on follicle function, including fibre growth. Follicles grown in the absence of growth factors maintained their anagen morphology for 6 days as determined by light microscopy. During this time they incorporated [3H]thymidine into the DNA of the bulb matrix and outer root sheath (ORS) cells and produced fibre keratins as detected by immunohistochemistry. In the presence of EGF and TGF alpha, fibre production ceased after 4 days, as it does following the administration of EGF in vivo. Cessation of fibre growth was not accompanied by regression of the follicle bulb which occurs in vivo. Follicle length growth did not differ significantly from controls and cells in the bulb continued to proliferate. Usually, the structure of the dermal papillae resembled that in control follicles, which was also in marked contrast to changes reported in vivo. In EGF- and TGF alpha-treated follicles, [3H]thymidine continued to be incorporated into DNA of the ORS and bulb after fibre growth ceased. Although wool keratin synthesis ceased, cytokeratins of the epidermis and ORS continued to be produced in the bulb as detected by immunochemistry. These bulb cells were also positive for the periodic acid-Schiff (PAS) reaction indicating the presence of glycogen, a normal component of ORS cells. The observations that cell proliferation continued in the bulb, that glycogen was present and that soft keratins were expressed in these cells suggest that the bulb cell population was induced to differentiate into an ORS phenotype by EGF and TGF alpha.

Castrate yearling male sheep were treated for 8 weeks with either 50 micrograms/kg body wt/8 hourly sc insulin-like growth factor-I (IGF-I) (n = 10) or with saline (n = 9). IGF-I treatment increased plasma IGF-I from 235 +/- 17 to 347 +/- 16 ng/ml (P less than 0.001). There was a gradual divergence in body wt (P less than 0.10) between treatment groups. Food intake did not change significantly. The weight of the spleen corrected for body wt increased by 40% (P less than 0.001) and there was a marginal increase in adjusted kidney wt (P less than 0.1). There was no effect of IGF-I on carcass weight or dimensions, or on long bone length, although the weight per unit length of the tibia (P less than 0.05) and femur (P less than 0.10) were increased. There was no effect on wool growth. Plasma IGF binding proteins (IGFBPs) were quantified by ligand blot analysis. In the IGF-I treated group, IGFBP-1 showed a transient increase (P less than 0.05) at day 3 but was similar in both groups at day 55 of treatment. IGFBP-2 was suppressed (P less than 0.05) by day 55 and IGFBP-3 and 4 did not change. Plasma glucose was elevated (P less than 0.05) and plasma insulin was suppressed (P less than 0.01) from 280 +/- 32 pg/ml to 124 +/- 30.4 pg/ml, plasma urea (P less than 0.01) and creatinine (P less than 0.05) were reduced in the IGF-I treated group. The somatogenic effect of IGF-I in this study was minimal suggesting that in the well fed animal with an intact somatotropic axis IGF-I treatment at doses which double plasma IGF-I does not enhance somatic growth performance. However, the marked splenomegaly shows the sensitivity of splenic growth to systemic IGF-I. The suppression of insulin with chronic IGF-I treatment was accompanied by hyperglycaemia--this may explain in part the lack of a significant anabolic response and may limit the utility of IGF-I therapy unless higher doses with insulin-like effects are used.

Oxygen and air low-temperature plasma treatment leads to significant changes in fibre cuticle cell membrane (skin flakes). Both lipids and proteins were destroyed. The processes of intensive lipid oxidation resulted from low-temperature plasma action. This factor seems to change critical surface tension, wetting and increasing penetration of dyes through the cuticle.

Twenty Rambouillet wether lambs were given ad libitum access to a diet with (BAA, n = 10) or without (control, n = 10) 1 ppm of the beta-adrenergic agonist L644,969. Lambs were fed to a constant slaughter weight end point of 54.5 kg. Carcasses were fabricated to yield bone-in and boneless cuts that were trimmed progressively to 1.27, .64, .32, and .00 cm of s.c. fat remaining. Addition of BAA did not affect growth traits. Actual and adjusted fat thickness, body wall thickness, and percentage of kidney-pelvic fat did not differ between control and BAA lambs. However, BAA increased longissimus muscle area, longissimus muscle depth, and leg score while decreasing USDA yield grade. The BAA increased carcass conformation scores and decreased flank lean color scores. No other carcass quality measurements were affected by BAA. Addition of BAA did not affect overall carcass yields of bone-in retail cuts. However, BAA increased overall carcass yields of boneless retail cuts regardless of fat trim level. The BAA increased bone-in leg yield. Yield of boneless sirloin, bone-in loin and boneless loin were not affected by BAA. For these cuts, the percentage change from the control was highly dependent on fat trim level. There was no difference in short-cut, shank-off, semiboneless leg yield between control and BAA. Addition of BAA did not affect yield of bone-in rack regardless of fat trim level. However, BAA greatly increased yield of boneless ribeye. The BAA did not affect yield of bone-in or boneless shoulder.(ABSTRACT TRUNCATED AT 250 WORDS)

Four experiments were conducted to determine whether leucine's alpha-ketoacid, alpha-ketoisocaproate (KIC), would influence lamb growth, feed conversion, and carcass composition. In the first experiment, lambs were injected intraperitoneally with 3.5 g of Na-KIC per day. In the second experiment, KIC unprotected from rumen degradation was fed at a rate of 15 g per animal daily. In a third experiment, KIC, leucine, and isovalerate (IVA), protected from rumen degradation, were fed to growing lambs at a rate of 1 g per animal per day. Finally, a fourth experiment was conducted in which ruminally protected KIC was fed to growing lambs at a rate of 1 g per animal per day. Ketoisocaproate tended to increase ADG and decrease fat deposition in all four experiments. Ketoisocaproate increased ADG by 11 (P less than .09), 10 (P less than .05), 9, and 13% in 1 through 4, respectively, and feed efficiency improved 5, 9 (P less than .02), 5, and 5%, respectively. Fat thickness over the 12th rib decreased 28 (P less than .06), 11, 17 (P less than .04), and 5% in Exp. 1 through 4, and the perirenal fat depot also decreased 13, 5, 18, and 3%, respectively. In contrast, neither ruminally protected leucine nor IVA affected the growth of young lambs. Together these studies indicate that administration of KIC to growing lambs can increase weight gain and muscle growth while decreasing fat deposition.

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)

A human growth hormone-releasing factor analogue, [DesNH2Tyr1,D-Ala2,Ala15]hGRF(1-29)NH2 (GRF-A), was infused s.c. into lambs for 28 d to determine its effects on growth performance and carcass composition. Twenty crossbred wethers weighing 47.0 +/- .5 kg were implanted with 7-d osmotic minipumps at weekly intervals. Minipumps contained either vehicle (dimethyl sulfoxide:H2O, 1:1) or GRF-A, released at a rate of 208 pmol (or .7 micrograms).h-1.kg-1. During the infusion period, plasma GH levels were increased (P less than .01) in GRF-A-treated wethers compared with control wethers (15.0 vs 9.3 ng/ml) and were higher on days that closely followed minipump implantation. Plasma IGF-I and hepatic IGF-I RNA concentrations were similar in lambs of both groups. Analogue treatment improved feed conversion (4.9 vs 5.8 kg dry matter/kg gain, P less than .05), increased average daily gain (.35 vs .30 kg, P = .05) and had no effect on feed intake, wool growth and body, carcass, selected organ and pituitary weights. Carcasses from GRF-A-infused lambs had less adjusted fat depth, a lower percentage of fat and a higher percentage of protein (P less than .05) than carcasses from control lambs. Magnitude of most effects of GRF-A on carcass measurements were correlated with the mean GH level that a lamb had during the infusion period. In conclusion, s.c. infusion of GRF-A improved feed utilization and altered carcass composition of feeder lambs in a relatively short period of time (28 d).

In wheat-fed sheep, supplemented abomasally with 1.5-6.0 g methionine per day, poor formation and improper keratinization of the wool fibres were evident 4 days after the start of the methionine supplementation. This led to kinking of the fibres. Subsequently severe distortion of the fibres, accompanied by gross thickening of the outer root sheaths, occurred in the distal (upper) halves of most follicles. Within this thickened region partial degradation of the distorted fibres occurred before emergence from the skin surface, causing a marked reduction in the tensile strength of the wool. It is postulated that kinking of the fibres stimulated the accumulation of outer root sheath cells, which led to hyperactivity of the process that normally degrades the inner root sheath, so that the poorly keratinized fibres were also partly degraded. Thickening of the epidermis and cellular infiltration of the upper dermis sometimes occurred during the infusions of methionine, whereas there were negligible effects on the sebaceous and sweat glands. Disappearance of the excess accumulation of outer root sheath cells after cessation of the methionine supplementation occurred gradually following improvement in keratinization and elimination of kinking of the fibres.

Varying amounts of DL-, L- or D-ethionine were administered intravenously to sheep, either as a continuous infusion, usually over 2 days, or as a single injection. Groups of sucking mice and rats, in their first cycle of hair growth, were given subcutaneous injections of DL-ethionine at several dose rates. Ethionine was a potent inhibitor of wool growth in sheep; the L- and D-isomers appeared equally effective. An infusion of 20 mg/kg DL-ethionine (c. 50 mg/kg0.75) given at a daily rate of 10 mg/kg for 2 days, or an injection of 40 mg/kg DL-ethionine (c. 100 mg/kg0.75), were sufficient to cause the growth of very weak wool and allow the fleece to be readily removed by hand within 3 weeks after dosing. The inhibition of wool growth was usually associated with a concentration of ethionine in blood plasma, during intravenous infusion, of 10 mumol/l or higher. An infusion of DL-ethionine at a daily rate of 1 mg/kg for 12 days caused the growth of weak fibres and substantially reduced both length growth rate and diameter of fibres. The toxicity of ethionine to sheep was dependent on the total dose and the duration of administration. An infusion of 40 mg/kg (20 mg/kg daily for 2 days) produced severe effects, but the sheep recovered; a dose of 14 mg/kg (2 mg/kg daily for 7 days) was lethal. The effects of ethionine on wool growth were reduced or prevented by the concurrent infusion of methionine (10-15 mol/mol ethionine). Doses of DL-ethionine as high as 460 mg/kg0.75 failed to cause hair loss in sucking mice. While body growth was severely retarded at this dose, no deaths occurred. Likewise, DL-ethionine failed to cause hair loss in sucking rats, but was lethal to some rats at a dose of 360 mg/kg0.75.

Plasma concentrations of dexamethasone have been measured in sheep during an 8-day infusion of dexamethasone-21 phosphate. The dexamethasone concentration profiles generally revealed a reproducible pattern with three phases--a peak during the first 48 h infusion which was followed by falling concentrations during the next 5 days, and a small increase in dexamethasone concentration during the final 24 h infusion was not uncommon. The pattern of dexamethasone concentrations was retained when dosage was arranged in such a way as to infuse increasing quantities of hormonal analogue as infusion progressed. Aspects of the metabolism of the analogue are discussed. Endogenous thyroxine and cortisol were significantly depressed during infusion. In these experiments wool was completely shed in three out of four animals dosed at a rate of 8.5 mg dexamethasone/kg0.75. The recovery of wool growth to its pretreatment values occurred by about one month after infusion. The consumption of food and body weight increases were satisfactory during the post-infusion period.

After sheep were defleeced with mimosine, cyclophosphamide or N-[5-(4-aminophenoxy)pentyl]-phthalimide, the first samples of the new growth of wool differed markedly in composition from the pretreatment samples, there being substantial reductions in the high-tyrosine proteins and increases in the high-sulfur proteins. Similar results were obtained with mice dehaired with mimosine and with sheep treated with low levels of mimosine which resulted in weakened wool rather than depilation. The composition of later samples of the regrowth wool showed progressive changes with time. The high-tyrosine proteins tended to approach the pretreatment levels, although this may take up to 12 weeks to occur, whereas the levels of high-sulfur proteins, after the initial increase, often fell below normal. In experiments involving defleecing with cyclophosphamide, the level of the latter proteins was still below normal after 3 months. The possibility that this altered protein composition of keratin fibres is characteristic of that portion of fibre first produced by a new or regenerating follicle was investigated in sheep and mice. It was found that wool follicles regenerating after plucking, and newly operating follicles in young sheep and mice, also produced wool and hair with a reduced content of high-tyrosine proteins. It is suggested, therefore, that the apparent long-term inhibition of the high-tyrosine proteins may not be the direct consequence of the administration of the chemical but rather be characteristic of normal wool and hair regrowth. Infusion of an amino acid mixture lacking methionine into the abomasum of sheep caused the growth of weak wool but did not suppress the synthesis of the high-tyrosine proteins. This is in contrast with previous findings that treatments which weaken wool also suppress high-tyrosine proteins.

A 5 X 5 Latin square design was used to study the effects on nitrogen balance, wool growth and plasma amino acids of infusing methionine and (or) glucose into the abomasum of growing wethers fed formaldehyde-treated Coastal bermudagrass (F-CBG) or untreated Coastal bermudagrass hay. Daily treatments were: (1) CBG; (2) F-CBG + 3 g methionine (met); (4) F-CBG + 96 g glucose and (5) F-CBG + 3 met + 96 g glucose. Glucose infusion decreased (P < .005) moles/100 g of total essential amino acids in plasma; moles/100 g of lysine, valine, leucine and isoleucine were also reduced (P < .005). Moles/100 g of methionine in plasma were increased significantly by methionine infusion, but nitrogen retention was not affected (P > .10). The grams digestible protein to megacalorie digestible energy (DE) ratio was 36.6, 35.9 and 32.4 for CBG, F-CBG and F-CBG + glucose, respectively. The decrease (36.6 to 32.4) resulted in increased nitrogen retained (P < .05), increased percentage nitrogen intake retained (P < .05) and increased percentage digested nitrogen retained (P < .01). Urinary nitrogen excretion was lower (P < .01) in wethers receiving the F-CBG + glucose treatment than in those receiving the F-CBG treatment (3.60 vs 5.09 g/day). Effects of formaldehyde treatment of CBG and rumen infusion of monensin on quantities of various crude protein (CP) components reaching the abomasum were also determined in a 4 X 4 Latin square design experiment. Total CP reaching the abomasum increased (P < .01) with formaldehyde treatment and resulted in increased quantities of amino acids reaching the abomasum (P < .05). Monensin had no effect on these two parameters, and no interaction between monensin and formaldehyde was observed. Dietary CP reaching the abomasum increased with formaldehyde treatment (P < .005) and with infusion of monensin (P < .025). Total microbial protein (MP) and MP reaching the abomasum per 100 g dry matter digested were not influenced by either formaldehyde or monensin.

An 8-wk growth trial was conducted to assess the effects of ovine growth hormone (oGH; 7 mg/d, sc) on growth performance and carcass composition of normal, growing wether lambs. Diethylstilbestrol (DES; .1 mg/d, sc) and control lambs were included for comparisons. Plasma oGH levels at 8 wk were 1.9, 5.5 (P less than .05) and 138.1 ng/ml (P less than .001) for controls, DES and oGH lambs, respectively. Diethylstilbestrol did not increase plasma oGH until the fourth week. The oGH improved feed conversion 7.4% (FC; P less than .05), but did not alter average daily gain (ADG) or feed intake (ADF). Diethylstilbestrol increased ADG 15.3% (P less than .05) and improved FC 16.1% (P less than .01), with no effect on ADF. The primary effect of oGH on carcass composition was to decrease the quantity of fat 8.9% (P less than .05). In addition, oGH may have increased protein 6.5% (P less than .10) and moisture 4.0% (not significant). Diethylstilbestrol increased the quantity of carcass protein 10% (P less than .01) and moisture 8.7% (P less than .05), with no effect on fat. In these studies, the primary effect of exogenous oGH on normal, growing lambs was to reduce carcass fat, which may account for the observed improvement in FC. Diethylstilbestrol, at 1/70th of the oGH dose, was superior to oGH for improving FC (P less than .05) and ADG (P less than .10). Improvements in body weight of the lambs given DES were observed 2 wk before an increase in plasma oGH. In addition, DES, unlike exogenous oGH, did not alter the quantity of carcass fat. These observations do not support the concept that the mode of action of DES is through increased GH secretion.

Seasonal cycles in the size of the testes, blood plasma concentration of testosterone, FSH and prolactin, intensity of the sexual skin flush, timing of rutting behaviour and moulting of the body coat were recorded in Soay rams after s.c. implantation of melatonin contained in a Silastic envelope which increased the circulating blood levels of melatonin to 200-600 pg/ml for many months. Two groups of 8 adult rams were held under alternating periods of short days (8L:16D) and long days (16L:8D) to drive the seasonal cycles and the treatments with melatonin were initiated during the long or short days, and one group of 8 ram lambs was kept out of doors and given implants during the long days of summer (4 melatonin-implanted and 4 control (empty implants) rams per group). The treatments demonstrated that melatonin implants during exposure to long days resulted in a rapid 'switch on' of reproductive redevelopment similar to that produced by exposure to short days melatonin implants prevented the rams from showing the normal responses to changes in the prevailing photoperiod rendering them nonphotoperiodic; and long-term cyclic changes in testicular activity, prolactin secretion and other characteristics occurred in the melatonin-implanted rams; the pattern was similar to that previously observed in rams exposed to prolonged periods of short days. The overall results are consistent with the view that melatonin is the physiological hormone that relays the effects of changing photoperiod on reproduction and other seasonal features, and that continuous exogenous melatonin from an implant interferes with the normal 'signal' and produces an over-riding short-day response.

During the i.v. infusion of a depilatory dose (100 micrograms/kg bodyweight) of mouse epidermal growth factor (EGF) into ovariectomized Merino ewes the frequency of pulsatile LH release was significantly reduced. However, the amplitude of pulses of LH secretion, either those naturally occurring or those induced by LHRH injection, was unchanged or only slightly reduced. Similar infusions of mouse EGF were made in progestagen-treated anoestrous Merino ewes in which LH secretion was maintained by injections of LHRH. These ewes did not experience oestrus or ovulate in response to PMSG injected 1 day after mouse EGF treatment (2 days before progestagen withdrawal); both responses occurred in controls. The EGF-treated ewes experienced oestrus and ovulated following progestagen-PMSG treatment 6 weeks later. These results suggest that mouse EGF inhibits the hypothalamic pulse generator responsible for LH release in the ewe but has little if any effect on pituitary sensitivity to LHRH; and mouse EGF apparently has a direct effect on the ovaries, temporarily impairing their ability to ovulate in response to exogenous gonadotrophin.

Mimosine was administered orally to Merino sheep once daily for periods of 1-3 days, either as the isolated compound or in the foliage of Leucaena leucocephala. A single daily dose of mimosine of 450 or 600 mg/kg body weight was effective for defleecing sheep. A daily dose rate of 300 mg/kg was effective for defleecing sheep if given on two successive days. The effectiveness of a treatment for defleecing sheep was related to the concentration of mimosine in plasma following dosing; defleecing ensued when the concentration of mimosine in plasma was maintained above 0-1 mmol/l for at least 30 h. The main products excreted in urine were mimosine and 3,4-dihydroxypyridine (DHP); small amounts of mimosinamine were also excreted. During the first day following dosing, the major excretory product was mimosine; DHP was an important component during the second and third days. In the three days following the start of dosing, between 32 and 53% of the mimosine given was accounted for as mimosine in the urine. Following an intravenous infusion of mimosine, no DHP was detected in urine; most of the mimosine was excreted intact but a small amount (c. 9%) was excreted as mimosinamine.

The present study investigates the effects of dosage and different modes of delivery of mouse epidermal growth factor (EGF) on the production of breaks in the fleece and on wool growth in Merino wethers. Subcutaneous infusions of EGF of greater than or equal to 0 . 25 mg kg-0.75 for 7-28 h resulted in a dose-dependent total or partial inhibition of wool production 2-4 weeks later. A complete break appeared in the fleece that was shed. Lower doses had lesser inhibitory effects on wool growth: the fleece was not shed but bore a zone of weakness, termed an incomplete break. Inclusion of the glucocorticoid analogue dexamethasone in the infusate did not alter the action of EGF on the fleece. Although a higher plane of nutrition increased the rate of fibre production, it did not alter the extent of inhibition of wool growth by EGF. Infusion of a peptide from EGF, which lacked eight of the C-terminal amino acids (EGF1-45), was as effective as the parent molecule in inhibiting wool growth. EGF administered as a single subcutaneous injection was less reliable as a method for producing breaks in the fleece. Of seven wethers that received EGF at a dose level between 0 . 27 and 0 . 32 mg kg-0.75, only three shed their fleeces. The remainder either developed incomplete breaks in the wool or were not affected. Administration of EGF at a dose level of 0 . 56 mg kg-0.75 via a rumen tube to one sheep had no discernible inhibitory effect on wool growth.

Pregnant ewes at 57, 75 and greater than or equal to 101 days of gestation were infused with approximately 3 mg of epidermal growth factor (EGF) for a period of 24-28 h. The strength of attachment of the wool fibres to the skin became progressively reduced during the week following treatment. After 3 weeks, the mean forces required to pluck staples had declined to between 10 and 30% of the pre-infusion measurements and the fleeces were able to be removed easily by hand. Increases in growth hormone and placental lactogen occurred in plasma of ewes during EGF treatment. Prolactin was not affected by EGF but circulating levels of thyroxine declined. The concentrations of these hormones returned to approximate pretreatment values within 24 h of the end of infusion. EGF treatment at the dose levels used did not appear to significantly affect the development or viability of the foetus.

Lys-beta-urogastrone, an analogue of human beta-urogastrone with an additional N-terminal lysine, was shown to have similar effects in mice and sheep to mouse epidermal growth factor (mEGF). Lys-beta-urogastrone in doses of 0.18-3.24 micrograms g-1 body weight caused both precocious separation of eyelids and eruption of incisors in neonatal mice. In 17 sheep, intravenous infusion of the urogastrone analogue over c. 24 h led, towards the end of infusion, to erythema of the muzzle, caused reductions in voluntary food intake (with doses greater than or equal to 50 micrograms kg-1) and generally easier manual harvesting of the fleece (with infusions greater than or equal to 81 micrograms kg-1), with spontaneous shedding of the fleece (c. 14 days after infusions of greater than or equal to 116 micrograms kg-1). In five sheep infusions of 25, 38, 50, 83 and 118 micrograms kg-1 fleece-free body weight, plasma concentrations of lys-beta-urogastrone were near maximal 20 h after the infusions started and were, respectively, 1.1, 1.7, 5.5, 18 and 79 micrograms l-1 plasma. Plasma concentrations of gastrin, somatostatin and pancreatic polypeptide were determined in these five sheep. Plasma gastrin rose sixfold by the end of infusions of 25 micrograms kg-1 of the urogastrone analogue, and tenfold with the higher doses of infusion. Although plasma somatostatin concentrations were variable, a consistent trend was observed; lower levels were apparent during the lys-beta-urogastrone infusions. There was no discernible trend in pancreatic polypeptide concentrations.

Two groups of three Merino wethers were infused intravenously with either 0.12 mg mouse epidermal growth factor (mEGF)/kg fleece-free body weight or 0.9% (w/v) NaCl over 24 h. Sheep treated with mEGF rejected food during treatment but feed intake was kept equal for both groups. Wool growth and plasma concentrations of mEGF were measured during the experiment. Pieces of skin taken from the wool-growing regions of the body were incubated with radioactive thymidine in order to measure its rate of incorporation into DNA. The skin was then divided at about the level of the sebaceous glands into sections that contained the upper dermis and epidermis (E sections) and those containing the generative wool-follicle bulbs (D sections). No mEGF was detected in the controls whereas mean levels of about 35 micrograms mEGF/1 plasma were detected during the last 4 h of infusion in the protein-treated group. After infusion, wool growth was reduced by about 20% of the mean pretreatment level in the controls and no shedding of wool fibre was evident. In the mEGF-treated sheep, on the other hand, wool growth was depressed by 75-95% of the mean pretreatment level and the fleeces were almost completely cast in all three of the animals, leaving them nude on the wool-growing regions of the body. Wool growth was restored to its pretreatment level in this group about 1 month after infusion. The D sections of skin contributed 50-60% of skin wet weight in controls throughout the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

The defleecing effects of the long-acting derivatives of prednisolone, triamcinolone and dexamethasone were compared with those of betamethasone alcohol when these steroids were administered at the rate of 3.3 mg/kg liveweight in three equal intramuscular injections of 1.1 mg to Merino wethers. Prednisolone showed no defleecing activity whereas the other steroids produced positive but variable responses. Prolonged depression of wool growth was evident following treatment with dexamethasone esters. Betamethasone alcohol injected intramuscularly at 1.1 mg/kg daily for 3 days produced a similar defleecing response to intravenous infusion of 3.3 mg/kg betamethasone phosphate over 8 days. A range of dose rates (0.3-3.3 mg/kg) of betamethasone as multiple and single intramuscular injections indicated that the minimum effective defleecing dose was approximately 2.1 mg/kg. The response to simultaneous administration of betamethasone and insulin or chlorpropamide (to increase glucose utilization) and glucose or xylazine (to increase hyperglycaemia) suggested that the gluconeogenic role of this steroid had little effect on fibre shedding. Thyroxine (300 micrograms per sheep) administered on the first day with an injection of betamethasone (0.9 mg/kg), and alone daily for 20 days thereafter, did not influence the changes in wool production resulting from betamethasone treatment. These results are discussed in relation to the molecular structure and physiological characteristics of a potentially specific defleecing steroid.

The effect on wool growth of thyroidectomy with subsequent thyroxine replacement at subnormal and supranormal levels has been investigated in Merino rams fed a restricted basal diet. Thyroidectomy without thyroxine replacement caused a greater than 60% reduction in wool growth. Provision of 30% of normal plasma thyroxine concentrations was sufficient to return wool growth to normal. Similarly, complete replacement of plasma thyroxine levels gave normal wool growth while increasing thyroxine concentrations to three times normal increased wool growth to levels slightly above normal. These results provide a possible explanation for the inability of other workers to correlate seasonal thyroxine patterns and annual wool growth variations.

A trial was carried out to determine whether selenium responsive unthriftiness existed on a property in the Strathbogie ranges of Central Victoria where unthriftiness of young sheep has been a problem for 10 to 20 years. White muscle disease had been diagnosed on the property in the previous year and on other properties in the area. Eighty Merino ewes and lambs were allotted to one of 4 groups in a 2 x 2 factorial designed trial in which sodium selenite (0.1 mg/kg) was given orally to ewes and/or lambs at marking time and to treated lambs at 3 monthly intervals thereafter. Selenium treatment of the ewes had no significant effect on subsequent lamb performance. Selenium treatment of the lambs produced significant responses: mortality in treated groups was 0% compared with 17.5% in untreated groups; body weight gains were 1.9 kg higher at both weaning and one year of age in treated than in untreated lambs; mean fleece weight was 14.4% higher in treated lambs and they produced 39% more wool than the surviving untreated lambs.