Acute nutrient treatment causes alterations in intra-follicular antioxidation and AKT signaling.

This study aimed to determine if short-term nutrient alteration affects (1) ovarian morphology, (2) plasma and ovarian antioxidant capability and (3) cell apoptosis and AKT signaling within the ovary. After estrus synchronization, 24 Hu sheep were assigned to three groups based on the nutrient requirement recommended for maintenance (M): 1 × M (Control), 1.5 × M (S) and 0.5 × M (R) during days 7-14 of their estrous cycle. The results indicated that undernourishment significantly increased the counts and volume of follicles <2.5 mm and decreased the counts and volume of follicles ≥2.5 mm (P < 0.05). Feed restriction altered the plasma and follicular redox balance within follicles ≥2.5 mm by inhibiting total antioxidant capacity, increasing malondialdehyde concentration (P < 0.05) and reducing the mRNA expression levels of superoxide dismutase 2 (SOD2) and glutathione peroxidase (GSH-PX), as well as the activities of total SOD and GSH-PX. Feed restriction also attenuated B-cell lymphoma-2 (BCL2) but enhanced Bcl-2-associated X protein (BAX) and BAX/BCL2 transcription and translation levels in granulosa cells (P < 0.05). Uniform staining intensities of AKT and P-AKT-Ser473 were observed in each follicle stage, whereas weaker P-AKT-Thr308 staining in the antral follicle than in the pre-antral follicle suggested possible involvement of P-AKT-Thr308 during the beginning of follicle development. P-AKT-Ser473 levels in follicles ≥2.5 mm was significantly reduced in the R group (P < 0.05). The results presented in this study demonstrate that suppressed folliculogenesis caused by feed restriction might be associated with attenuated AKT signaling, reduced follicular antioxidant capacity and enhanced granulosa cells apoptosis.

Carcass traits, meat quality, antioxidant status and antioxidant gene expression in muscle and liver of Hu lambs fed perilla seed.

The effects of perilla (Perilla frutescens L.) seed on carcass traits, meat quality, antioxidant status and antioxidant gene expression in the liver and muscle of Hu lambs were investigated in this study. Sixty Hu lambs (23.02 ± 1.36 kg) were randomly divided into four experimental groups receiving diets containing 0%, 5%, 10% or 15% perilla seed (CD, 5%PFSD, 10%PFSD and 15%PFSD, respectively). The addition of perilla seed had no significant impacts on carcass traits (p > .05). There were no differences in pH, meat colour, drip loss, cooking loss or shear force among the four treatments (p > .05). Addition of perilla seed increased (p < .05) deposition of intramuscular lipids but had no effect on other chemical components in the longissimus dorsi (LD) (p > .05). The 15%PFSD diet decreased the total antioxidant capacity (T-AOC) and malondialdehyde (MDA) content in the liver (p < .05 for both) but increased the activity of these antioxidant enzymes in LD (p < .05 for both). Compared to CD, addition of perilla seed increased superoxide dismutase (SOD) and glutathione peroxidase (GPX) expression in the liver and LD (p < .05 for all). These results indicate that perilla seed supplementation in lambs' diets can increase deposition of intramuscular lipids and improve muscular oxidative status and meat quality.

Effect of Age on Energy Requirement for Maintenance and Growth of Dorper and Hu Crossbred F1 Ewes Weighing 20 to 50 kg.

This research aimed to define the energy requirement of Dorper and Hu Hybrid F1 ewes 20 to 50 kg of body weight, furthermore to study energy requirement changes with age and evaluate the effect of age on energy requirement parameters. In comparative slaughter trial, thirty animals were divided into three dry matter intake treatments (ad libitum, n = 18; low restricted, n = 6; high restricted, n = 6), and were all slaughtered as baseline, intermediate, and final slaughter groups, to calculate body chemical components and energy retained. In digestibility trial, twelve ewes were housed in individual metabolic cages and randomly assigned to three feeding treatments in accordance with the design of a comparative slaughter trial, to evaluate dietary energetic values at different feed intake levels. The combined data indicated that, with increasing age, the net energy requirement for maintenance (NEm) decreased from 260.62±13.21 to 250.61±11.79 kJ/kg(0.75) of shrunk body weight (SBW)/d, and metabolizable energy requirement for maintenance (MEm) decreased from 401.99±20.31 to 371.23±17.47 kJ/kg(0.75) of SBW/d. Partial efficiency of ME utilization for maintenance (km, 0.65 vs 0.68) and growth (kg, 0.42 vs 0.41) did not differ (p>0.05) due to age; At the similar condition of average daily gain, net energy requirements for growth (NEg) and metabolizable energy requirements for growth (MEg) for ewes during late fattening period were 23% and 25% greater than corresponding values of ewes during early fattening period. In conclusion, the effect of age upon energy requirement parameters in the present study were similar in tendency with previous recommendations, values of energy requirement for growth (NEg and MEg) for Dorper and Hu crossbred female lambs ranged between the NRC (2007) recommendation for early and later maturating growing sheep.

Trace element concentrations and distributions in the main body tissues and the net requirements for maintenance and growth of Dorper × Hu lambs.

A comparative slaughter trial was conducted to estimate the trace element concentrations and distributions in the main body tissues and the net requirements for maintenance and growth of Dorper × Hu crossbred lambs. Thirty-five lambs of each gender (19.2 ± 0.36 kg initial BW) were used. Seven lambs of each gender were randomly chosen and slaughtered at approximately 20 kg BW as the baseline group for measuring initial body composition. Another 7 lambs of each gender were also randomly chosen and offered a pelleted mixed diet for ad libitum intake and slaughtered at approximately 28 kg BW. The remaining 21 sheep of each gender were randomly divided into 3 groups with 7 sheep each and assigned to ad libitum or 40 or 70% of ad libitum intake of a pelleted mixed diet (42:58 concentrate:roughage, DM basis). The 3 groups of each gender were slaughtered when the sheep fed ad libitum reached approximately 35 kg BW. Empty body (head + feet, hide, viscera + blood, and carcass) trace element contents were determined after slaughter. The results showed that the trace elements were mainly distributed in viscera (blood included), except for Zn, which was mainly distributed in the muscle and bone tissues. The net requirements were calculated using the comparative slaughter technique. For males and females, the daily net trace element requirements for maintenance were 356.1 and 164.1 µg Fe, 4.3 and 3.4 µg Mn, 42.0 and 29.8 µg Cu, and 83.5 and 102.0 µg Zn per kilogram empty body weight (EBW), respectively. Net requirements for growth decreased from 65.67 to 57.27 mg Fe, 0.35 to 0.25 mg Mn, and 3.45 to 2.82 mg Cu and increased from 26.36 to 26.65 mg Zn per kilogram EBW gain (EBWG) for males. Net requirements for growth decreased from 30.66 to 22.14 mg Fe, 0.43 to 0.32 mg Mn, 2.86 to 2.18 mg Cu, and 27.71 to 25.83 mg Zn per kilogram EBWG for females from 20 to 35 kg BW. This study indicated that the net trace element requirements for Dorper × Hu crossbred lambs may be different from those of purebred or other genotypes, and more data are needed for sheep in general.

Effects of different dietary intake on mRNA levels of MSTN, IGF-I, and IGF-II in the skeletal muscle of Dorper and Hu sheep hybrid F1 rams.

MSTN, IGF-І(insulin-like growth factor-І) and IGF-II (insulin-like growth factor-II) regulate skeletal muscle growth. This study investigated the effects of different dietary intake levels on skeletal muscles. Sheep was randomly assigned to 3 feeding groups: 1) the maintenance diet (M), 2) 1.4 x the maintenance diet (1.4M), and 3) 2.15 x the maintenance diet (2.15M). Before slaughtering the animals, blood samples were collected to measure plasma urea, growth hormone, and insulin concentrations. After slaughtering, the longissimus dorsi, semitendinosus, semimembranosus, gastrocnemius, soleus, and chest muscle were removed to record various parameters, including the mRNA expression levels of MSTN and IGFs, in addition to skeletal muscle fiber diameter and cross-sectional area. The result showed that as dietary intake improved, the mRNA expression levels of MSTN and IGF-II decreased, whereas IGF-Іexpression increased. The mRNA expression levels of MSTN and IGFs were significantly different in the same skeletal muscle under different dietary intake. The skeletal muscle fiber diameter and cross-sectional area increased with greater dietary intake, as observed for the mRNA expression of IGF-І; however, it contrasted to that observed for the mRNA expression of MSTN and IGF-II. In conclusion, dietary intake levels have a certain influence on MSTN and IGFs mRNA expression levels, in addition to skeletal muscle fiber diameter and cross-sectional area. This study contributes valuable information for enhancing the molecular-based breeding of sheep.

Amplified fragment length polymorphism analysis to assess crossover interference and homozygosity in gynogenetic diploid Pacific abalone (Haliotis discus hannai).

Recombination analysis in gynogenetic diploids is a powerful tool for assessing the degree of inbreeding, investigating crossover events and understanding chiasma interference during meiosis. To estimate the marker-centromere recombination rate, the inheritance pattern of 654 amplified fragment length polymorphism (AFLP) markers was examined in the 72-h veliger larvae of two meiogynogenetic diploid families in the Pacific abalone (Haliotis discus hannai). The second-division segregation frequency (y) of the AFLP loci ranged from 0.00 to 0.96, with 23.9% of loci showing y-values higher than 0.67, evidencing the existence of interference. The average recombination frequency across the 654 AFLP loci was 0.45, allowing estimation of the fixation index of 0.55, indicating that meiotic gynogenesis could provide an effective means of rapid inbreeding in the Pacific abalone. The AFLP loci have a small proportion (4.4%) of y-values greater than 0.90, suggesting that a relatively low or intermediate degree of chiasma interference occurred in the abalone chromosomes. The information obtained in this study will enhance our understanding of the abalone genome and will be useful for genetic studies in the species.