In vitro and in vivo anti-cancer effects of hibernating common carp (Cyprinus carpio) plasma on metastatic triple-negative breast cancer

Uncontrollable proliferation is a hallmark of cancer cells. Cell proliferation and migration are significantly depressed during hibernation state. Many studies believe some factors in the plasma of hibernating animals cause these effects. This study aimed to assess the anti-cancer effects of hibernating common carp (Cyprinus carpio) plasma on 4T1 cancer cells in vitro and in vivo. The effect of hibernating plasma on cell viability, morphology, migration, apoptosis rate, and cell cycle distribution of 4T1 cells was investigated in vitro and in vivo. Hibernating plasma at a concentration of 16 mg/ml significantly reduced the viability of 4T1 cancer cells, without any toxicity on L929 normal fibroblast cells. It could change the morphology of cancer cells, induced apoptosis and cell cycle arrest at the G2/M phase, and inhibited migration. Furthermore, intratumoral injection of hibernating plasma (200 µl, 16 mg/ml) in the tumor-bearing mice caused a significant inhibition of 4T1 breast tumors volume (46.9%) and weight (58.8%) compared with controls. A significant decrease in the number of metastatic colonies at the lungs (80%) and liver (52.8%) of hibernating plasma-treated animals was detected which increased the survival time (21.9%) compared to the control groups. Immunohistochemical analysis revealed a considerable reduction in the Ki-67-positive cells in the tumor section of the hibernating plasma-treated animals compared with controls. Taken together, the SDS-PAGE and mass spectrometry analysis indicated the alpha-2-macroglobulin level in the hibernating fish plasma was significantly increased. It could exert an anti-cancer effect on breast cancer cells and suggested as a novel cancer treatment strategy.

A multifunctional nanocomposite spray dressing of Kappa-carrageenan-polydopamine modified ZnO/L-glutamic acid for diabetic wounds

Sprayable bioadhesives with exceptional properties were developed for application in wound healing. In this study, a visible light-crosslinkable nanocomposite bioadhesive hydrogel with multifunctional properties was proposed. While methacrylated Kappa-carrageenan (KaMA), mimicking the natural glycosaminoglycan was applied as the hydrogel matrix, various concentrations of polydopamine modified ZnO (ZnO/PD) nanoparticles (0, 0.5, 1 and 2 wt%) was loaded in it to improve its mechanical, antibacterial and cellular properties. Moreover, L-glutamic acid was incorporated in the nanocomposite hydrogel network to accelerate wound healing. The nanocomposite hydrogels revealed significant mechanical property and recovery ability, comparable elasticity with human skin and great adhesiveness. For instance, the tensile strength of KaMA hydrogel enhanced from 64.1 ± 10 to 80.3 ± 8 kPa and elongation jumped from 20 ± 4% to 61 ± 5% after incorporation of 1 wt% ZnO/PD nanoparticles. The nanocomposite hydrogels demonstrated effectual blood clotting ability and biocompatibility, >95% cell viability after 3 days of incubation. In vivo experiments also suggested that L-glutamic acid loaded nanocomposite hydrogel considerably accelerated wound healing with superior granulation tissue thickness than control in a full-thickness skin defect model. Taken together, this visible-light crosslinking nanocomposite hydrogel with significant properties could be used to spray on a wound area to eliminate wound infection and accelerate wound healing process.

Spirulina extract enriched for Braun-type lipoprotein (Immulina®) for inhibition of 4T1 breast tumors' growth and metastasis

Spirulina platensis extracts have exhibited considerable anti-cancer effects. To investigate the efficacy of the Spirulina extract enriched for Braun-type lipoprotein (Immulina®) for breast cancer treatment, 4T1 breast tumor-bearing mice were treated with 40 mg/kg Immulina® daily and the tumors' growth and metastasis were assessed. Also, CD4, CD8, and CD56 staining were performed to investigate the Immulina® effect on the immune cells' recruitment to the tumors by immunohistochemistry. Immulina® could significantly (P < 0.001) inhibit 4T1 breast tumors' growth. Immulina®-treated group exhibited a 63% decrease in the tumors' volume in comparison with control (P < 0.001). Also, Immulina® could significantly (P < 0.001) decrease metastatic burden at the vital organs as 68% and 61% decrease in the liver and lungs metastatic colonies were observed, respectively. Also, Immulina® could increase mean survival time of the tumor-bearing mice for 29 days. The Spirulina-treated mice tumors contained significantly more infiltrated NK, CD4+, and CD8+ T lymphocytes in comparison with control. Taking together, Immulina® can be a safe anti-cancer supplement with the ability to cause direct apoptosis to the cancer cells and activate the immune system against tumor. This supplement with natural origin seems to have bright future to help breast cancer patients.

Induction of Tyrosine Hydroxylase Gene Expression in Embryonal Carcinoma Stem Cells Using a Natural Tissue-Specific Inducer

A large number of studies have focused on the generation of dopaminergic neurons from pluripotent cells. Differentiation of stem cells into distinct cell types is influenced by tissue-specific microenvironment. Since, central nervous system undergoes further development during postnatal life, in the present study neonatal rat brain tissue extract (NRBE) was applied to direct the differentiation of embryonal carcinoma stem cell line, P19 into dopaminergic (DA) phenotypes. Additionally, a neuroprotective drug, deprenyl was used alone or in combination with the extract. Results from morphological, immunofluorescence, and qPCR analyses showed that during a period of one to three weeks, a large percentage of stem cells were differentiated into neural cells. The results also indicated the greater effect of NRBE on the differentiation of the cells into tyrosine hydroxylase-expressing cells. MS analysis of NRBE showed the enrichment of gene ontology terms related to cell differentiation and neurogenesis. Network analysis of the studied genes and some DA markers resulted in the suggestion of potential regulatory candidates such as AVP, ACHE, LHFPL5, and DLK1 genes. In conclusion, NRBE as a natural native inducer was apparently able to simulate the brain microenvironment and support neural differentiation of P19 cells.

The combined effects of three-dimensional cell culture and natural tissue extract on neural differentiation of P19 embryonal carcinoma stem cells

Tissue engineering, as a novel transplantation therapy, aims to create biomaterial scaffolds resembling the extracellular matrix in order to regenerate the damaged tissues. Adding bioactive factors to the scaffold would improve cell-tissue interactions. In this study, the effect of chitosan polyvinyl alcohol nanofibres containing carbon nanotube scaffold with or without active bioglass (BG⁺ /BG^- ), in combination with neonatal rat brain extract on cell viability, proliferation, and neural differentiation of P19 embryonic carcinoma stem cells was investigated. To induce differentiation, the cells were cultured in α-MEM supplemented with neonatal rat brain extract on the scaffolds. The expression of undifferentiated stem cell markers as well as neuroepithelial and neural-specific markers was evaluated and confirmed by real-time Reverse transcription polymerase chain reaction (RT-PCR) and immunofluorescence procedures. Finally, the three-dimensional (3D) cultured cells were implanted into the damaged neural tubes of chick embryos, and their fates were followed in ovo. Based on the histological and immunofluorescence observations, the transplanted cells were able to survive, migrate, and penetrate into the host embryonic tissues. Gene network analysis suggested the possible involvement of neurotransmitters as a downstream target of synaptophysin and tyrosine hydroxylase. Overall, the results of this study indicated that combining the effects of 3D cell culture and natural brain tissue extract can accelerate the differentiation of P19 embryonic carcinoma cells into neuronal phenotype cells.

Wound healing properties of PVA/starch/chitosan hydrogel membranes with nano Zinc oxide as antibacterial wound dressing material

In this work, hydrogel membranes were developed based on poly vinyl alcohol (PVA), starch (St), and chitosan (Cs) hydrogels with nano Zinc oxide (nZnO). PVA/St/Cs/nZnO hydrogel membranes were prepared by freezing-thawing cycles, and the aqueous PVA/St solutions were prepared by dissolving PVA in distilled water. After the dissolution of PVA, starch was mixed, and the mixture was stirred. Then, chitosan powder was added into acetic acid, and the mixture was stirred to form a chitosan solution. Subsequently, Cs, St and PVA solutions were blended together to form a homogeneous PVA/St/Cs ternary blend solution. Measurement of Equilibrium Swelling Ratio (ESR), Water Vapor Transmission Test (WVTR), mechanical properties, scanning electron microscopy (SEM), MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide] assay, antibacterial studies, in vivo wound healing effect and histopathology of the hydrogel membranes were then performed. The examination revealed that the hydrogel membranes were more effective as a wound dressing in the early stages of wound healing and that the gel could be used in topic applications requiring a large spectrum of antibacterial activity; namely, as a bandage for wound dressing.

Effects of A 4-Week Aerobic Exercise on Lipid Profile and Expression of LXRα in Rat Liver

Objective

Liver X receptors (LXRs) are ligand-activated transcription factors of the nuclear hormonal receptor superfamily which modulate the expression of genes involved in cholesterol homeostasis. Hence, further unraveling of the molecular function of this gene may be helpful in preventing cardiovascular diseases.

Materials and Methods

This experimental intervention study included twelve adult Wistar male rats (12-14 weeks old, 200-220 g) which were divided into the control (n=6) and training (n=6) groups. The training group received exercise on a motor-driven treadmill at 28 meters/minute (0% grade) for 60 minutes a day, 5 days a week for 4 weeks. Rats were sacrificed 24 hours after the last session of exercise. A portion of the liver was excised, immediately washed in ice-cold saline and frozen in liquid nitrogen for extraction of total RNA. Plasma was collected for high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC) and triglycerides (TG) measurements. All variables were compared by independent t test.

Results

A significant increase in LXRα transcript level was observed in trained rats (P<0.01). Plasma HDL-C concentration was also significantly higher (P<0.01) in trained rats. There was a significant decrease in the concentrations of LDL-C (P<0.01) and TC (P<0.02), and the ratios of TC/HDL-C (P<0.001) and LDL/HDL-C (P<0.002) in trained rats. However, the TG concentration was unchanged (P>0.05).

Conclusion

We found that endurance training induces significant elevation in LXRα gene expression and plasma HDL-C concentration resulting in depletion of the cellular cholesterol. Therefore, it seems that a contributor to the positive effects of exercise in cardiovascular disease prevention is through the expression of LXRα, which is a key step in reverse cholesterol transport.

Overexpression of SORCIN is a Prognostic Biomarker for Multidrug-Resistant Pediatric Acute Lymphoblastic Leukemia and Correlates with Upregulated MDR1/P-gp

BACKGROUND

Multidrug resistance is one of the major causes of treatment failure in pediatric acute lymphoblastic leukemia (ALL), and SORCIN is an intracellular calcium modulator protein. The current study was designed to investigate the in vitro and in vivo relationships between the expression levels of SORCIN: in tumor cell lines and children with ALL; its possible correlation with MDR1/P-glycoprotein (P-gp), a multidrug resistance-related gene; and response to therapy.

MATERIALS AND METHODS

Childhood T-lymphoblastic leukemia (CCRF-CEM) cell lines resistant to methotrexate (MTX) were developed. Patient studies were performed by including 30 children with ALL at diagnosis, 3 children with bone marrow relapse, and 15 children with no symptoms of cancer. The mRNA expression profiles of SORCIN and MDR1/P-gp was assessed using quantitative polymerase chain reaction (qPCR). Minimal residual disease (MRD) was measured in the patient population, a year following the initial therapy using qPCR.

RESULTS

Cell line data analyses showed a positive correlation between SORCIN mRNA levels and resistance to MTX. The difference between patient and control groups for SORCIN expression levels was not significant. However, patients with a negative response to therapy showed an increase in SORCIN mRNA levels (up to 6.8-fold) compared with those with negative MRD. In addition, the results demonstrated a significant positive correlation between SORCIN and MDR1/P-gp gene expression levels.

CONCLUSION

The current study introduces, for the first time, a possible prognostic value of SORCIN in childhood ALL, which may be correlated with MDR1/P-gp gene expression in these patients.

Effect of Nanosilver Particles on Procaspase-3 Expression in Newborn Rat Brain

Objective

Nanotechnology focuses on materials having at least one dimension of less than 100 nanometers. Nanomaterials such as Nanosilver (NS) have unique physical and chemical properties such as size, shape, surface charge. NS particles are thought to in- duce neuronal degeneration and necrosis in the brain. It has been reported that NS parti- cles generate free radicals and oxidative stress which alters gene expression and induces apoptosis. This study was designed to evaluate whether the detrimental effect of NS parti- cles is through the activation of Procaspase-3 during fetal neural development.

Materials and Methods

In this experimental study, thirty Wistar female rats at day one of pregnancy were semi-randomly distributed into three groups of ten. Group 1, the control group, had no treatment. From day 1 to the end of pregnancy, groups 2 and 3 received 1 and 10 ppm NS respectively via drinking water. Newborn rats were sacrificed immediately after birth and their brains were dissected and kept frozen. Total RNA, extracted from brain homogenates, was reverse transcribed to cDNA. Quantitative real-time polymerase chain reaction (PCR) analysis was undertaken to estimate the expression level of Procaspase-3.

Results

Developmental exposure to NS induced neurotoxicity and apoptosis. This corre- lated with a significant increase in Procaspase-3 expression level especially at 10 ppm NS.

Conclusion

The pro-apoptotic activity of NS in cells is likely to due to the dysregula- tion of Procaspase-3.

Impacts of fresh lime juice and peel on atherosclerosis progression in an animal model

BACKGROUND

The main protective role of antioxidants in the progression of atherosclerosis has been shown in some studies. Therefore, this project evaluated the effects of Citrus aurantifolia (Christm) juice and peel on antioxidant activity and atherosclerosis progression in rabbits receiving a hypercholesterolemic diet.

METHODS

Forty white New Zealand male rabbits were randomly allocated to four groups. All groups were on hypercholesterolemic diet for two months. While the first group was considered as the hypercholesterolemic control, groups 2 and 3 (intervention groups) received 5 ml/day lime juice and 1 g/day dried lime peel powder, respectively. Group 4 was fed a normal diet (normal control). Before and after the study, weight was measured and a fasting blood specimen was taken from the rabbits. Serum lipids analyses and antioxidant activity evaluations were then performed. The rabbits' aorta and coronary arteries were separated and the presence of fatty streaks was studied.

RESULTS

Comparing to the hypercholesterolemic control group (-25.2 ± 7.0), only the plasma total antioxidant capacity change was significantly more in rabbits supplemented with lime juice (16.3 ± 14.7) and peel (8.6 ± 7.1) (P = 0.008). The presence of fatty streaks in coronary arteries and aorta of the intervention groups [juice (0.2 ± 0.01); peel (0.0 ± 0.00)] was significantly decreased compared to the hypercholesterolemic control group (1.2 ± 0.4) (P < 0.001).

CONCLUSION

Based on our findings, Citrus aurantifolia peel and juice increase plasma antioxidant capacity in rabbits, and can thus prevent or decelerate the process of atherogenesis. However, lime peel is more effective than lime juice.

mRNA expression profile of multidrug-resistant genes in acute lymphoblastic leukemia of children, a prognostic value for ABCA3 and ABCA2

Multidrug resistance (MDR) is an important cause of treatment failure in acute lymphoblastic leukemia (ALL). The ABC family of membrane transporters is proposed, albeit with controversy, to be involved in this process. The present study aims to investigate the mRNA expression profile of several genes of this family, including ABCA2, ABCA3, ABCB1/MDR1, MRP1/ABCC1, MRP3/ABCC3, ABCG2/BCRP, and the intracellular transporter MVP/LRP, in childhood ALL, and to evaluate their association with response to therapy. Some genes in the present research are being studied for the first time in Iran. Using quantitative real-time PCR, we evaluated 27 children with ALL at diagnosis and 15 children with normal bone marrow. The status of response to therapy was assessed one year after the onset of therapy through investigating the IgH/TCRγ gene rearrangements. Our findings indicate a considerable and direct relationship between mRNA expression levels of ABCA2, ABCA3, MDR1, and MRP1 genes and positive minimal residual disease (MRD) measured after one year of treatment. Statistical analysis revealed that expression of these genes higher than the cutoff point will raise the risk of MRD by 15-, 6.25-, 12-, and 9-fold, respectively. No relationship was found between of MVP/LRP, MRP3 and ABCG2 genes expression and ALL prognoses. Considering the direct and significant relationship between the increased expression of ABCA2, ABCA3, MDR1, and MRP1 genes and positive risk of MRD in children with ALL, evaluating the expression profile of these genes on diagnosis may identify high risk individuals and help plan a more efficient treatment strategy.

Endurance training enhances LXRα gene expression in Wistar male rats

Liver X receptor α (LXRα) is a member of the ligand-activated transcription factor of nuclear hormonal receptor superfamily, whose activation leads to modulation in the expression of genes involved in cholesterol homeostasis including ATP-binding cassette transporter A1 (ABCA1), which plays a crucial role in plasma high-density lipoprotein cholesterol (HDL-C) remodeling. The purpose of this study was to investigate whether endurance training enhanced the expression level of liver LXRα gene. Twelve adult male Wistar rats (200-220 g) were divided into control and training groups. Training group received exercise on a motor-driven treadmill at 28 m/min (0 % grade) for 60 min/day, 5 days/week for 8 weeks. Twenty-four hours after the last exercise session, the rats were killed and blood was taken from the right ventricle of each rat. Plasma was collected for HDL-C, low-density lipoprotein cholesterol (LDL-C), TC and TG measurements. Furthermore, a portion of the liver of each rat was excised and washed in ice-cold saline and frozen in liquid nitrogen for assessment of LXRα and ABCA1 mRNA levels. Data indicated significant increase in both LXRα and ABCA1 mRNA levels in trained rats, compared to control rats. Plasma HDL-C concentration was significantly higher (P < 0.001) in trained rats at the end of treadmill exercise. However, there was a significant decrease in LDL-C (P < 0.003), TG, TC concentration, TC/HDL-C and LDL/HDL-C ratios in trained rats compared with those in the control group (P < 0.001). In conclusion, we found that endurance training induced significant elevation in LXRα gene expression, which correlated with enhanced levels of ABCA1 mRNA and plasma HDL-C concentration.

Quantitative expression of phospholipase C zeta, as an index to assess fertilization potential of a semen sample

BACKGROUND

Failed fertilization post-ICSI has been mainly attributed to the sperm's inability to induce oocyte activation. Phospholipase C zeta (PLCζ) is considered to be one of the factors for the induction of oocyte activation. The aim of this study was to quantitatively assess the expression of PLCζ in globozoospermic men or those with previously low or failed fertilization in comparison with fertile men or those with high fertilization potential. In addition, the relationship between expression of PLCζ and that of other sperm markers was evaluated.

METHODS

Real-time PCR was carried out to evaluate relative expression of PLCζ mRNA. Chromatin maturity and acrosin activity were assessed by CMA3 staining and a colorimetric method.

RESULTS

The expression of PLCζ was significantly lower in globozoospermic men (P< 0.01, n= 8) or individuals with previously low or failed fertilization (P< 0.01, n= 36) in comparison to fertile men (n= 24). In addition, a significant difference was observed between globozoospermic (P< 0.01) and individuals with previously low or failed fertilization (P= 0.003) in comparison to high fertilization individuals (n= 17). Expression of PLCζ was not correlated with either chromatin maturity or acrosin activity. However, a significant correlation was observed between the percentage of fertilization and relative expression of PLCζ (r= 0.4, P< 0.01).

CONCLUSION

In this study, for the first time, we have shown that assessment of relative expression of PLCζ may provide a useful marker for the ability of sperm to induce oocyte activation after ICSI.

Effects of alfalfa on lipoproteins and fatty streak formation in hypercholesterolemic rabbits

Alfalfa (Medicago sativa) is a leguminous plant with high contents of phytoestrogen and saponin which are both useful in preventing cardiovascular disorders. This study was designed to evaluate the preventive effect of dietary alfalfa on the development and the progression of atherosclerosis in hyperlipidemic rabbits. Twenty male rabbits were obtained and kept under standard conditions. After 2 weeks of accommodation to the new place, the animals were semi-randomly distributed into four groups of five each. Animals in Group 1 received basic diet and the ones in Group 2 received the same diet to which 1% cholesterol was added. Groups 3 and 4 received similar diets as Groups 1 and 2 respectively, but supplemented with alfalfa. Each of the four groups was fed with its respected diet for a period of 12 weeks. Fasting blood samples were collected from all animals at the beginning and at the end of the study and blood factors were measured. At the end of the study samples from the right and the left coronary arteries as well as the aorta were collected from all animals for pathological evaluations. Though dietary alfalfa decreased total cholesterol, LDL and triglyceride and this effect was not significant, but dietary alfalfa significantly increased HDL. The formation of fatty streaks in the aorta, the right and the left coronary arteries were significantly reduced under the influence of dietary alfalfa. The indication that dietary alfalfa may have preventive effects on the progression of fatty streak formation calls for more studies to clarify the mechanisms of the effect.

Effects of dietary red clover on blood factors and cardiovascular fatty streak formation in hypercholesterolemic rabbits

Phytoestrogens with a biological activity like estradiol are naturally found in many plants. This study was designed to investigate the effect of red clover, a phytoestrogen-rich member of the legume family (Trifolium pratense) on the development of atherosclerosis in male hyperlipidemic rabbits. Twenty rabbits were semi-randomly distributed into four groups of five each. Two groups received either normal diet or normal diet supplemented with red clover. Two other groups received similar diets to both of which 1% cholesterol was added. Dietary use of red clover (RC) in hyperlipidemic rabbits significantly decreased C-reactive protein (CRP), triglyceride (TG), total cholesterol and LDL-cholesterol (LDL-C) whereas, HDL-cholesterol (HDL-C) was significantly increased in those animals (p < 0.05). Fatty streak formation was also significantly lower in aorta and left and right coronary arteries in the same animals due to use of dietary RC supplementation. These findings suggest that dietary RC may reduce cardiovascular risk factors.

Effects of gestational and lactational exposure to TCDD or coplanar PCBs on spatial learning

Recently we reported that in utero and lactational exposure to specific ortho-substituted polychlorinated biphenyl (PCB) congeners resulted in a learning deficit on a delayed spatial alternation (DSA) task in female rats. In this study, spatial learning and memory was assessed following in utero and lactational exposure to coplanar PCBs or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Time-mated Sprague-Dawley rats were dosed with PCB 77 (3,3',4,4'-tetrachlorobiphenyl), 2 or 8 mg/kg/day; PCB 126 (3,3',4,4',5-pentachlorobiphenyl), 0.25 or 1.0 micrograms/kg/day; TCDD, 0.025 or 0.1 micrograms/kg/day; or corn oil vehicle via gavage on gestation days 10-16. Litters were culled to eight on day 2 and weaned on day 21. Beginning on day 80, one male and one female from each litter were tested on an eight-arm radial maze working memory task. The TCDD-exposed rats displayed pronounced decreases in errors relative to controls. PCB 77- and PCB 126-exposed rats showed similar, but less pronounced, decreases in errors. The same animals were later tested on a T-maze DSA task, but no differences among groups were observed. In conclusion, perinatal exposure to low doses of TCDD or structurally related coplanar PCBs appeared to facilitate acquisition of a working memory task on the radial arm maze. This effect was very different from that previously observed in rats exposed to ortho-substituted PCB congeners. The rats exposed to ortho-substituted PCBs did not differ from controls on the radial arm maze and were impaired on the T-maze DSA task. Together these findings suggest that coplanar and ortho-substituted PCBs may have different mechanisms of action on the CNS.

Spatial learning deficits in adult rats exposed to ortho-substituted PCB congeners during gestation and lactation

Spatial learning and memory was assessed in rats following gestational and lactational exposure to specific ortho-substituted PCBs. Time-mated Sprague-Dawley rats were exposed to PCB 28 (2,4,4'-trichlorobiphenyl), 8 or 32 mg/kg/day, PCB 118 (2,3',4,4',5-pentachlorobiphenyl), 4 or 16 mg/kg/day, PCB 153 (2,2',4,4',5,5'-hexachlorobiphenyl), 16 or 64 mg/kg/day, or corn oil vehicle via gavage on Gestation Days 10-16. Litters were culled to eight on Day 2 and weaned on Day 21. Beginning on Day 90, one male and one female from each litter were tested on a working/reference memory task on an eight-arm maze. For each rat, the same four arms were baited throughout training. Animals were tested Monday-Friday, for seven consecutive weeks. No differences in working or reference memory errors were observed. The same animals were later tested on a T-maze delayed spatial alternation task. On each trial, the reinforcer was placed in the arm opposite that chosen by the rat on the previous trial. Intertrial delays of 15, 25, or 40 sec appeared in counterbalanced order. Rats were tested Monday-Friday for three consecutive weeks. The higher doses of all three congeners resulted in slower acquisition by female rats. Males were not affected. PCB-exposed females were impaired at all delays and were not differentially more impaired at longer delays, suggesting a learning or attentional deficit, rather than a mnemonic deficit. These findings demonstrate that perinatal exposure to ortho-substituted PCBs can result in long-lasting deficits in learning and suggest that the effects of PCBs on learning may be sex specific.

Effects of perinatal exposure to specific PCB congeners on thyroid hormone concentrations and thyroid histology in the rat

Time-mated Sprague-Dawley rats were exposed to PCB 28 (2,4,4'-trichlorobiphenyl), 8 or 32 mg/kg/day; PCB 118 (2,3',4,4',5-pentachlorobiphenyl), 4 or 16 mg/kg/day; or PCB 153 (2,2',4,4',5,5'-hexachlorobiphenyl), 16 or 64 mg/kg/day. At weaning, serum thyroxine (T4) was markedly depressed in pups, but not dams, exposed to PCB 118 or 153. Triiodothyronine (T3) was unchanged in pups and dams. In a histological evaluation of thyroids, the PCB 118 pups revealed changes suggestive of sustained TSH stimulation, including increased follicular cell vacuolization and height, increased nuclear vesiculation, and decreased colloid area. Decreases in body and brain weights and increases in liver weights were observed in some groups, with the high dose PCB 118 pups showing the greatest effect.

Effect of duration of fasting on postmolt laying hen performance

Two experiments were conducted to examine the effects of varying length of feed withdrawal on postmolt laying hen performance. Commercial laying hens (65 wk of age) were fed continuously or fasted for 4 or 10 days in Experiment 1 and fed continuously or fasted for 4, 7, or 14 days in Experiment 2. Egg production performance was evaluated for 35 wk of production following initiation of fasting. Hen-day egg production (Weeks 1 to 35) and egg weight (Weeks 5 to 35) did not differ between treatments in Experiment 1; however, in Experiment 2, egg production was depressed for the 14-day fasted hens compared with the fed hens. Lower egg weight also occurred for the 14-day fasted hens compared with the fed, 4-, or 7-day fasted hens in Experiment 2. Egg yield (grams of egg per hen per day) for Weeks 5 to 35 was lower for fed hens versus the 4- or 10-day fasted groups in Experiment 1, but no treatment differences occurred in Experiment 2. Feed efficiency (grams of egg per gram of feed) for Weeks 5 to 13 was not affected by length of fasting in Experiment 1, but feed efficiency of hens fasted for 14 days was lower (P less than .05) than that of hens on other treatments in Experiment 2. Egg specific gravity was highest for hens fasted for 10 or 14 days and was lowest for fed hens, with egg specific gravity for hens fasted for 4 or 7 days being intermediate (P less than or equal to .05). The results indicated that fasting periods of less than 10 days may yield satisfactory egg production and egg weight but that eggshell quality may be enhanced by using fasting periods of 10 days or longer.

Effect of protein and methionine levels in molt diets on postmolt performance of laying hens

Three experiments were conducted to evaluate the effects of feeding molt diets varying in protein content and supplemental Met on postmolt layer performance. Laying hens (70, 65, or 96 wk of age) were induced to molt by fasting (feed only) until 26 to 28% body weight loss occurred. Six molt diets consisting of 16, 13, or 10% CP with or without .15% supplemental Met were then fed until egg production reached approximately 10%, at which time all hens received a 16% CP layer diet for 30 wk in Experiments 1 and 2 and for 4 wk in Experiment 3. In Experiment 1 (summer), hens regained body weight more rapidly, returned to production faster, and had larger egg weights (Weeks 1 to 4) when fed the 16 or 13% CP molt diets than when fed the 10% CP molt diet. Long-term egg production, egg yield (grams of egg per hen per day) (Weeks 1 to 30), and feed efficiency (Weeks 1 to 8) were greater for hens fed the 16 or 13% CP molt diets compared with those fed the 10% CP molt diet. The Met supplementation had no effect on postmolt performance. In Experiment 2 (winter), the only significant treatment effect was that Met supplementation increased egg weight (Weeks 1 to 30). Molt diet treatments had no consistent effect on egg specific gravity during the last 4 wk of the postmolt production period in Experiments 1 or 2. The effects of the dietary treatments on early postmolt performance in Experiment 3 (early fall) were similar to those observed in Experiment 1. The present study indicated that protein content, but not Met supplementation, in molt diets influenced postmolt performance of hens during the summer and early fall experiments, but not in the winter experiment.

Effect of sodium aluminosilicate on phosphorus utilization by chicks and laying hens

Three experiments were conducted to evaluate the effects of sodium aluminosilicate (SAS) on performance of chicks and laying hens fed diets varying in nonphytate P (NPP), phytate, and fiber content. In two chick growth experiments a corn and soybean meal diet and a phytate and fiber-free casein-dextrose diet were used. These diets contained .1% NPP and 1.1% Ca and were fortified with 0, .05, or .10% P from KH2PO4 and 0 or .5% SAS. A 3 x 2 factorial arrangement of treatments was used. Sodium aluminosilicate supplementation significantly (P less than .05) depressed growth of chicks fed the corn and soybean meal diets containing 0 or .05% supplemental AP. Sodium aluminosilicate addition decreased (P less than .05) tibia ash and total tibia P (tibia weight x P concentration) in both chick experiments, with the effect being greater for chicks fed the corn and soybean meal diet. In the laying hen experiment, birds were fed corn and soybean meal diets containing NPP levels of .1, .45, or 1.8% and SAS levels of 0 or 1.0%. Egg production and egg yield were depressed (P less than .05) by feeding diets containing .1 or 1.8% NPP, and egg specific gravity was decreased (P less than .05) by feeding 1.8% NPP. Addition of SAS to the .1% NPP diet caused a large reduction (P less than .05) in egg production, egg weight, and feed efficiency, whereas SAS supplementation of the 1.8% NPP diet had no significant effect. Sodium aluminosilicate supplementation increased (P less than .05) egg specific gravity for hens fed the .1 and 1.8% NPP diets.(ABSTRACT TRUNCATED AT 250 WORDS)