Seasonal changes in plasma steroid levels in relation to ovarian steroidogenic ultrastructural features and progesterone receptors in the house gecko, Hemidactylus flaviviridis, in Oman.

A comprehensive study of the annual ovarian cycle in the house gecko, Hemidactylus flaviviridis, was conducted in Oman. Circulating estradiol (E(2)), progesterone (P), and testosterone (T) were measured during the active and inactive phases of the cycle. The steroid levels were related to the steroidogenic ultrastructural features such as the abundance of smooth endoplasmic reticulum (SER), the presence of cisternal whorls, and close association of lipid droplets with swollen vesiculated mitochondria and SER. The steroids were measured using a sensitive detection technique HPLC-MS/MS. E(2) levels began to rise in January at the onset of vitellogenesis and continued to rise between February and May relative to ovulation, postovulation, gravidity and oviposition. Afterwards, E(2) remained low during the inactive phase (June-December). P levels increased significantly in March and peaked in April, which coincided with luteinization. P levels began to decline relative to luteolysis (May-June). Afterwards, it remained low throughout the inactive phase. T levels rose significantly in March-April coinciding with vitellogenesis, but decreased rapidly and significantly in May and remained low during the inactive phase. Progesterone receptors (PR), identified using immunohistochemistry, were strongly expressed during the breeding period, but were absent during the non-breeding period. The appearance of the steroidogenic ultrastructural features in the preovulatory and lutein granulosa cells was correlated with the significant rise in the three steroid levels and the PR. As the steroid levels declined, the granulosa cells underwent a general degeneration and disruption of the associated steroidogenic features.

Effects of electrical stimulation on histochemical muscle fiber staining, quality, and composition of camel and cattle Longissimus thoracis muscles.

The effects of electrical stimulation on muscle fiber type, meat quality, and composition of Longissimus thoracis muscles from one-humped camels and Dofari Omani cattle of a comparable age range were investigated. A low-voltage electrical stimulation with 90 V, 14 Hz (pulse of 7.5-millisecond duration every 70 milliseconds) 20 min postmortem was applied. Samples from the left muscle were collected from 20 (2 to 3 y) camels and 24 cattle (1 to 3 y). For chemical composition, muscle samples were dried in a freeze dryer, and then ground to determine moisture, protein, fat, and ash. Macro- and micro-minerals were determined using an Inductively Coupled Plasma Emission Spectrometer. Quality characteristics of the meat were evaluated using shear force value, pH, sarcomere, myofibrillar fragmentation index, expressed juice, cooking loss percent, and CIE L*, a*, b* color values. Electrical stimulation resulted in a significantly (P < 0.05) more rapid pH fall in the muscle during the first 24 h after slaughter in both species. Muscles from electrically stimulated carcasses had significantly (P < 0.05) lower ultimate pH, longer sarcomere, and lower shear force values than those from nonstimulated carcasses. Lightness (L*), myofibrillar fragmentation, and expressed juice were significantly (P < 0.05) higher for stimulated than for nonstimulated muscles. Muscles of camels had significantly (P < 0.05) higher expressed juice, cooking loss percent, redness color (a*), and lower fat, Mg, K, and P than those from cattle. Electrical stimulation improved quality characteristics of meat from both species. This indicates that meat quality of local camel and cattle can be improved by electrical stimulation and consequently improves their acceptability to consumers and better marketability.

Ultrastructural features and elemental distribution in eggshell during pre and post hatching periods in the green turtle, Chelonia mydas at Ras Al-Hadd, Oman.

Eggshells were randomly collected from turtle nests immediately after oviposition and at the end of incubation to examine the ultrastructural features using scanning JSM-5600LV microscopy. Three layers were recognized; an outer calcareous, a middle multistrata and an inner membrane. The calcareous layer had loose nodular units varying in shape and size without interlocking attachments. In freshly laid eggs, each nodular unit had spicules arranged in folded stacks. The spicules became unfolded during incubation, to form radiating configurations. Elemental composition and mapping of the layers were analyzed using energy dispersive spectroscopy (EDS). The elements were unevenly distributed throughout the eggshell and Ca(2+) decreased significantly after hatching. X-ray diffraction was used to identify the crystals of the eggshells. It revealed that nodular units of the calcareous were made up of CaCO(3), as aragonite (91%), calcite (6%) and vaterite (3%). The middle layer consisted of organic amorphous material with aragonite (89%) and calcite (11%). The shell membrane consisted of reticular fibers with crystals predominantly of NaCl halite. Thermogravimetry analysis of the calcareous layer indicated a complete evaporation of bonded H(2)O at 480 degrees C and CO(2) at 830 degrees C. Using the differential thermal analysis (DTA), aragonite was transformed to stable calcite at 425 degrees C.

Effect of low voltage electrical stimulation on biochemical and quality characteristics of Longissimus thoracis muscle from one-humped Camel (Camelus dromedaries).

The effects of electrical stimulation (90V) 20min post mortem on meat quality and muscle fibre types of four age group camels (1-3, 4-6, 7-9, 10-12 years) camels were assessed. Quality of the Longissimus thoracis at 1 and 7 days post mortem ageing was evaluated using shear force, pH, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss and L(∗), a(∗), b(∗) colour values. Age of camel and electrical stimulation had a significant effect on meat quality of L. thoracis. Electrical stimulation resulted in a significantly (P<0.05) more rapid pH fall in muscle during the first 24h after slaughter. Muscles from electrically-stimulated carcasses had significantly (P<0.05) lower pH values, longer sarcomeres, lower shear force value, higher expressed juice and myofibrillar fragmentation index than those from non-stimulated ones. Electrically-stimulated meat was significantly (P<0.05) lighter in colour than non-stimulated based on L(∗) value. Muscles of 1-3 year camels had a significantly (P<0.05) lower shear force value, and pH, but longer sarcomere, and higher myofibrillar fragmentation index, expressed juice, and lightness colour (L(∗)) than those of the 10-12 years camels. The proportions of Type I, Type IIA and Type IIB were 25.0, 41.1 and 33.6%, respectively were found in camel meat. Muscle samples from 1-3 year camels had significantly (P<0.05) higher Type I and lower Type IIB fibres compared to those from 10-12 year camel samples. These results indicated that age and ES had a significant effect on camel meat quality.