Effect of Galanin Infusion into the Third Ventricle on Plasma Concentrations of Metabolic Parameters in Goats Fed Diets of Different Energy Content

Khazali, H.,Towhidi, A.,Moravej, H.,Parhizkar, A. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.6

The goal of this study was to determine whether galanin affects the mean plasma concentrations of metabolic parameters such as thyroxine (T4), triiodothyronine (T3), growth hormone (GH), insulin, glucagon, glucose, fatty acid and urea in goats fed diets differing in energy content. Sixteen goats were randomly divided into 4 groups. Animals in groups 1 and 2 were fed 100% and animals in groups 3 and 4 were fed 50% energy content in the diet for 20 days. After 20 days, animals in groups 1 and 3 received a daily infusion of $1{\mu}g$ galanin and groups 2 and 4 received a daily infusion of $2{\mu}g$ galanin into their third ventricle for 5 days. Blood samples were collected daily from the jugular vein before infusion on day 4 until 4 days after the last infusion of galanin. Samples were assayed for plasma T3, T4, GH, insulin and glucagon concentrations by double-antibody RIA. Glucose, fatty acid and urea concentrations were also measured. Lower dietary energy intake and infusions of 1 and $2{\mu}g$ galanin significantly (p<0.01) decreased the mean plasma concentrations of T3, T4, insulin and glucose and significantly (p<0.01) increased the mean plasma concentrations of GH, glucagon, fatty acid and urea of the animals in groups 3 and 4. Different dosages of the galanin infusions did not change the plasma concentrations of the metabolic parameters in the animals fed a normal dietary energy content. The results of this experiment indicated that galanin may negatively affect T3, T4, insulin and glucose and increase GH, glucagon, fatty acid and urea in goats with negative energy balance, but not in those with positive energy balance.

Intravenous Orexin Reduces LH Secretion in Castrated Camelus Dromedaries Fed a Sub-maintenance Diet

Khazali, Homayoun Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.1

It has been shown that orexin has an inhibitory effect on gonadotropin secretions in non-ruminant animals. The goal of this study was to determine whether orexin affects LH, and FSH secretions in the camel, as a pseudo-ruminant animal, under different dietary energy content. Sixteen castrated camels were randomly divided into 4 groups. Animals in groups 1 and 2 were fed 100% and animals in groups 3 and 4 were fed 50% energy content in their diet for 20 days. After 20 days, animals in groups 1 and 3 received infusions of 1 $\mu{g}$ orexin and groups 2 and 4 received infusions of 2 $\mu{g}$ orexin into their jugular vein. Blood samples were collected from the jugular vein every 20 minutes from 4 h before the first infusion of orexin until 4 h after the last orexin infusion. Lower dietary energy intake and infusions of 2 $\mu{g}$ but not 1 $\mu{g}$ orexin significantly (p<0.01) decreased the mean plasma concentrations and pulse amplitudes of LH of the animals. Infusion of 1 and 2 $\mu{g}$ orexin did not change the secretions of LH of the animals fed NE. Different energy dietary intake and infusion of 1 and 2 $\mu{g}$ orexin did not change the mean plasma concentrations of FSH of the animals in all groups. Infusions of 1 and 2 $\mu{g}$ orexin significantly (p<0.01) decreased the glucose levels of animals fed LE but not in NE fed animals. Additionally, plasma glucose levels of the LE-fed animals in groups 3 and 4 were significantly (p<0.01) lower than those of the animals in groups 1 and 2 fed NE diet. The results of this experiment indicated that orexin may negatively affect LH and FSH in camels with negative energy balance, but not in those with positive energy balance.

Random Walk and Martingale Difference Hypotheses for Pacific Basin Foreign Exchange Markets

Osamah M. Al-Khazali,Chong Soo Pyun 한국재무학회 2009 한국재무학회 학술대회 Vol.2009 No.05

This paper examines the random walk (RW) and the martingale difference sequence (MDS) processes for the Australian dollar and seven Asian currencies relative to three benchmark currencies between 1993 and 2008. We use Wright’s (2000) non-parametric variance ratio test for the RW and Kuan and Lee’s (2004) test for the MDS. The results show that (i) the hypotheses of RW and MDS are rejected for all eight currencies for the entire study period as well as for the sub-period leading up to the Asian financial crisis in 1997; (ii) for the sub-period following the Asian crisis, only the Australian dollar and Korean won behave as weak-form efficient while the six other Asian emerging currencies show no discernible improvement toward market efficiency; (iii) on balance, the rejection of random walk is more robust by Kuan and Lee’s martingale test as compared to that by Wright’s sign and rank variance ratio test.

Leptin Is a Metabolic Signal for GnRH-LH/FSH Axis in Feed-restricted Ewes

Towhidi, A.,Khazali, H.,Zhandi, M. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.7

Two experiments were conducted to determine whether leptin is a metabolic signal for gonadotropin secretion in ewes. In the first experiment, twenty-eight cyclic Chal ewes were assigned randomly to an energy restricted, no leptin group (ERNL) (60% of maintenance; n = 14) and an energy normal, no leptin group (ENNL) (100% of maintenance; n = 14) for 71 days (6 estrous cycles). Estrus was synchronized with seven consecutive injections of $PGF_{2{\alpha}}$ Biweekly, body weight (BW) and body condition score (BCS) were determined and blood samples were collected to measure plasma leptin concentration. Blood samples were also taken to determine plasma progesterone concentration twice weekly. After each PG injection from the second injection to the end of experiment, four ewes were selected and blood samples were collected at 20 minutes and at hourly intervals for 3 h to detect plasma LH and FSH concentration. In the second experiment, after the ceasing of the estrous cycle caused by energy restriction, six acyclic ewes were selected and randomly allotted to two groups (n = 3) and received the following treatment for four days. Ewes in an energy restricted, leptin group (ERL) were fed with a ration which provided 60% of maintenance energy requirements and intravenously injected with $4{\mu}g$ leptin/kg BW daily. Ewes in an energy excess, no leptin group (EENL) were fed with a ration that provided 180% (120%+60%) of maintenance energy requirements and intravenously injected with 1 ml saline daily. In both groups, blood samples were collected at 20 minutes and at hourly intervals for 3 h before feeding on d 0 and d 5, and for 3 h before and after injections as above on d 2 and d 4 to detect plasma LH and FSH concentration. In the first experiment, BW and BCS from the $2^{nd}$ estrous cycle, and leptin from the $3^{rd}$ estrous cycle to the end of the experiment significantly (p<0.05) decreased. In ERNL ewes, mean plasma concentrations of FSH significantly (p<0.01) decreased from the $4^{th}$ estrous cycle to d 71 and LH pulsatile secretion was suppressed on d 71, so that, mean plasma concentrations of LH (p<0.05), LH pulse frequency (p<0.01) and LH pulse amplitude (p<0.05) significantly decreased. In the second experiment, injection of leptin significantly increased mean circulating concentrations of LH (p<0.05), LH pulse frequency (p<0.01), LH pulse amplitude (p<0.05) and mean circulating concentrations of FSH (p<0.01) and leptin (p<0.01). High energy intake significantly (p<0.05) stimulated pulsatile secretion of LH and leptin secretion (p<0.01), but non-significantly increased plasma FSH concentration. The results of this study indicate that leptin is a metabolic signal for the GnRH-LH/FSH axis in feed-restricted fat-tailed ewes.

Momentum Effect in the Oman Stock Market Over the Period of 2005-2018

GHARAIBEH, Omar Khlaif,AL-KHAZALI, Ahmad,AL-QURAN, Ali Zkariya Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.2

The purpose of this paper is to investigate the profitability of the momentum effects on the Oman Stock Market (OSM). This study uses the monthly returns of all stocks listed on the OSM, with a total of 107 companies used in the study for the period from 2005 to 2018. According to the methodology developed by Jegadeesh and Titman (1993), this study builds momentum portfolios based on various sizes. Moreover, the January effect is also examined to recognize if this effect is related to the momentum effect. The results find that there is evidence of momentum returns and these returns are statistically and economically significant. The sub-periods confirmed the profitability of the momentum strategy. This paper shows that momentum returns are evident at different sizes; big, medium, and small-sized portfolios. Besides, the result shows that the classic January effect does not play an important role in the momentum returns. Thus, the implication is that the momentum should not take into account the annual, seasonal, and size returns. The capital asset pricing model (CAPM) or the three-factor model cannot explain momentum returns generated by individual stocks in the Oman Stock Market. These results are useful to academia and investors alike.

Effect of Permanent Hypoinsulinemia on Appetite, Performance, Carcass Composition, Blood Metabolites and Leptin Concentrations in Lambs

Moslemipur, F.,Torbatinejad, N.M.,Khazali, H.,Hassani, S.,Ghoorchi, T. Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.6

Insulin has crucial roles in energy metabolism in all mammals but has been less studied in ruminants. An experiment was conducted to investigate the effects of hypoinsulinemia induction on appetite, performance, carcass composition and blood metabolite levels in sheep. Treatments were intravenous injection of four doses of streptozotocin; 0, 25, 50 and 75 mg/kg BW named C, L, M and H, respectively. Twenty male lambs were divided into four treatment groups. Animals in group H could not continue the experiment because of abnormalities. The duration of the experiment was eight consecutive weeks, and injection was performed at the end of week 3. Feed and water intakes were measured weekly and weight changes of animals were recorded and used for calculation of other growth parameters. Blood samples were collected weekly via venipuncture at fasting and 2.5 h post-prandial and analyzed for hormones and blood metabolites. Results showed a marked hypoinsulinemia in group M with significant decrease in fasted and postprandial insulin concentrations and also fasted leptin concentrations vs. the control group C (p<0.05). Group M showed significant increases in blood glucose, triglycerides, cholesterol, total protein, blood urea nitrogen and ketone body levels vs. group C (p<0.05). After injection, animals in group M showed diabetic hyperphagia and enhanced water intake as compared to group C (p<0.05) but, despite increased feed intake, they did not gain more weight than controls (p<0.05), and consequently, their feed conversion ratio was greater. Protein and fat contents of meat and liver were not significantly different among groups (p>0.05). In conclusion, the results suggested a regulatory role of insulin in energy metabolism of ruminants by exerting two opposing effects; central catabolic and peripheral anabolic.

New Nonparametric Tests for the Efficiency in Foreign Exchange Markets

Jae H. Kim,Chong Soo Pyun,Osamah M. Al-Khazali 한국재무학회 2010 한국재무학회 학술대회 Vol.2010 No.05

Using Kim’s (2009) wild bootstrapped automatic variance ratio (AVR) test and Kuan and Lee’s (2004) martingale difference sequence (MDS) test, we investigate the random walk (RW) and the martingale hypotheses for the Australian dollar and seven Asian currencies between 1993 and 2008. Our findings are that (i) the hypotheses of RW and MDS are rejected for all eight currencies for the entire study period as well as for the sub-period leading up to the Asian financial crisis in 1997; (ii) for the post-Asian crisis period, only the Australian dollar, Malaysian ringgit, and Korean won behave as weak-form efficient while the rest of five Asian currencies show no discernible improvement toward market efficiency. Our findings have broad policy implications - investors can exploit time-varying movements of the returns of the five currencies which can be identified by technical trading rules for profitable trading.