Molecular form identification of anterior pituitary gland-secreted prolactin in chicken.

Endocrine changes during bird reproduction are well documented. Prolactin (PRL) exhibits a strong relationship between incubation and broody behavior. The molecular forms of PRL in the anterior pituitary gland during the reproductive cycle have already been previously identified but not those in the secreted form. To identify the molecular forms of secreted PRL during the reproductive cycle, we thus monitored the physiological status and incubation behavior of 10 Silkie hens by a video recording system over 1-2 years. Nine out of ten mature hens exhibited incubation behavior multiple times during the experiment. Ten hens demonstrated two interesting features. In a typical clutch, hens spent 10-15 min in the nest to lay an egg. Once they spent over 1 h in the nest, the nest occupancy increased incrementally. This shift in the nest occupancy occurred 7-10 days before the incubation onset and was highly repeatable. Based on the behavior of the hens, we cultured the anterior pituitary gland during four stages (premature non-laying, laying, trans, and incubation) with physiological PRL-releasing factor, vasoactive intestinal peptide (VIP). Based on our two-dimensional protein analysis, glycosylated PRL (G-PRL) displayed several isoforms with varying isoelectric points (pI), whereas we could detect one primary signal for non-glycosylated PRL (NG-PRL). However, 3-4 NG-PRL isoforms were detected in the anterior pituitary gland. These results suggested that secreted PRL, especially from the trans and incubation stages, contains various isoforms and it is post-translationally glycosylated and phosphorylated.

Transcriptome and Proteome Analysis Revealed Key Pathways Regulating Final Stage of Oocyte Maturation of the Turkey (Meleagris gallopavo).

In birds, the zona pellucida (ZP) matrix that surrounds the ovulated oocyte-called the inner perivitelline layer-is involved in sperm-zona interaction and successful fertilization. To identify the important genes and proteins connected with the final step of egg development, next-generation sequencing and two-dimensional electrophoresis, combined with mass spectrometry, were used for the analysis of mature oocytes at the F1 developmental stage. A total of 8161 genes and 228 proteins were annotated. Six subfamilies of genes, with codes ZP, ZP1-4, ZPD, and ZPAX, were identified, with the dominant expression of ZPD. The main expression site for ZP1 was the liver; however, granulosa cells may also participate in local ZP1 secretion. A ubiquitination system was identified in mature oocytes, where ZP1 was found to be the main ubiquitinated protein. Analysis of transcripts classified in estrogen receptor (ESR) signaling indicated the presence of ESR1 and ESR2, as well as a set of estrogen-dependent genes involved in both genomic and nongenomic mechanisms for the regulation of gene expression by estrogen. Oxidative phosphorylation was found to be a possible source of adenosine triphosphate, and the nuclear factor erythroid 2-related factor 2 signaling pathway could be involved in the response against oxidative stress. Oocyte-granulosa cell communication by tight, adherens, and gap junctions seems to be essential for the final step of oocyte maturation.

The effects of varying concentrations of glutathione and trehalose in improving microscopic and oxidative stress parameters in Turkey semen during liquid storage at 5 °C.

Since turkey reproduction is mainly through artificial insemination, short-term preservation of turkey semen is one of the most important issues in turkey reproduction management. The present study investigates the effects of glutathione (GSH) and trehalose on lipid peroxidation degree and turkey semen quality while being stored at 5 °C for 72 h. To this end, semen samples were collected from 20 turkeys with a weekly frequency for 12 weeks. A glucose-based extender was used to dilute the pooled semen. It was divided into seven equal parts with varying levels of glutathione [0.5, 1 and 2 mM), trehalose [50, 75 and 100] and control [extender without antioxidant]. Subsequently, the divided semen samples were stored at 5 °C for 72 h. Several sperm parameters such as motility and motion parameters, plasma membrane integrity (PMI), plasma membrane functionality, DNA integrity, and oxidative parameters were assessed following storage for 0, 24, 48, and 72 h. The obtained results indicated an improvement in the plasma membrane functionality and DNA integrity, along with the percentages of PMI in GSH-2 mM group in comparison to the control group following storage at 5 °C for 72 h (P ≤ 0.05). It is also notable that the 2 and 1 mM concentrations of GSH increased the spermatozoa motility and motion parameters in comparison to the control group, respectively (P ≤ 0.05). The study results indicated that GSH-2, 1 mM and trehalose- 100 mM concentrations reduced lipid peroxidase levels and increased total antioxidant activity, catalase, superoxide dismutase, and glutathione peroxidase in comparison to the control group (P ≤ 0.05). Our study's data show that improvement of semen parameters and oxidative stress parameters of turkey semen can be improved by glutathione at 2 and 1 mM and trehalose at 75 mM while storing it 5 °C.

Characterization and biological role of cysteine-rich venom protein belonging to CRISPs from turkey seminal plasma†.

Turkey semen contains cysteine-rich secretory proteins (CRISPs) that belong to the dominant seminal plasma proteins. We aimed to isolate and characterize CRISP from turkey seminal plasma and evaluate its possible involvement in yellow semen syndrome (YSS). YSS, which is well characterized, causes reduced fertility and hatchability. The protein was purified using hydrophobic interaction, gel filtration, and reverse phase chromatography. It then was subjected to identification by mass spectrometry, analysis of physicochemical properties, and specific antibody production. The biological function of the isolated protein was tested and included its effects on sperm motility and migration and sperm-egg interactions. Sperm motility was measured with the CASA system using Hobson Sperm Tracker. The reproductive tract of turkey toms was analyzed for gene expression; immunohistochemistry was used for protein localization in the male reproductive tract, spermatozoa, and inner perivitelline layer. The isolated protein was identified as cysteine-rich venom protein-like isoform X2 (CRVP X2; XP_010706464.1) and contained feature motifs of CRISP family proteins. Turkey CRVP X2 was present in both spermatozoa and seminal plasma. The extensive secretion of CRVP X2 by the epithelial cells of the epididymis and ductus deferens suggests its involvement in post-testicular sperm maturation. The internally localized CRVP X2 in the proximal part of the sperm tail might be responsible for stimulation of sperm motility. CRVP X2 on the sperm head might be involved in several events prior to fusion and may also participate in gamete fusion itself. Although the mechanisms by which CRVP X2 mediates fertilization are still unknown, the involvement of complementary sites cannot be excluded. The disturbance of CRVP X2 expression can serve as an etiologic factor of YSS in the turkey. This study expands the understanding of the detailed mechanism of fertilization in birds by clarifying the specific role of CRVP X2.

Nutritional modulation of the antioxidant capacities in poultry: the case of selenium.

Natural antioxidants play important roles in maintaining chicken health, productive and reproductive performance of breeders, layers, rearing birds, and growing broilers. There is a wide range of antioxidant molecules in the body: vitamin E, carotenoids, selenium, ascorbic acid, coenzyme Q, carnitine, taurine, antioxidant enzymes, etc. In the body all antioxidants work together to create the antioxidant network called "antioxidant systems" with Se being the "chief-executive." Analysis of the current data on selenium roles in antioxidant defenses in poultry clearly showed its modulatory effect at the level of breeders, developing embryos, newly hatched chicks, and postnatal chickens. On the one hand, Se is involved in the expression and synthesis of 25 selenoproteins, including GSH-Px, TrxR, and SepP. On the other hand, Se affects non-enzymatic (vitamin E, CoQ, and GSH) and enzymatic (SOD) antioxidant defense mechanisms helping build strong antioxidant defenses. Se efficiency depends on the level of supplementation and form of dietary Se, organic Se sources being more effective modulators of the antioxidant systems in poultry than sodium selenite. Moreover, Se levels in eggs from some wild avian species are close to those found in chicken eggs after 0.3 ppm organic Se supplementation and a search for most effective dietary form of organic Se is a priority in poultry nutrition. Antioxidant/prooxidant (redox) balance of the gut and the role/interactions of Se and microbiota in maintaining gut health would be a priority for future poultry research.

Effects of extremely low frequency electromagnetic fields on turkeys.

Several studies have examined the potential biological effects of electromagnetic fields (EMF) on birds; however, little attention has been paid to the extremely low frequency (ELF; 0-300 Hz; 0-50 µT) radiation found in an urbanized environment. For monitoring the effects of ELF EMF, we used a turkey (Meleagris gallopavo) model, because the nucleated erythrocytes of turkeys contain ß-adrenoceptors, and norepinephrine- (NE-) activated ß-adrenoceptors have an important role in physiological and behavioral processes. Our aims were the following: 1) to investigate the intracellular mechanisms; 2) to compare the intracellular mechanisms in the treated and control groups over time, considering inter-individual differences and intra-subject correlations; 3) and to study the reversible nature of the response. The turkeys in the treatment group were treated in vivo with ELF EMF (50 Hz; 10 µT) for 3 wk after a 1-wk-long adaptation period. The animals were not exposed to ELF EMF during the regeneration period (5 wk following the exposure). The NE-activated ß-adrenoceptor function was detected by measuring the amount of 3΄5΄-cyclic-adenosine-monophosphate (cAMP), and the biochemical enzyme parameters were defined. Repeated measurements of cAMP levels were analyzed using marginal models and a piecewise linear mixed model to compare treatment and control groups over time. According to our results, NE-activated ß-adrenoceptor function was decreased in the treated birds in a time-dependent manner, while there were no differences between toxicological parameters in the serum, compared to the normal ranges. The decreased NE-dependent ß-adrenoceptor function could be compensated by the homeostatic complex during the 5-wk regeneration period. Extended experimental periods and more sophisticated analysis methods may help prevent harmful environmental effects on birds; furthermore, these findings could affect public health and the economy.

Modification of the lipid profile and antioxidant status of the blood plasma of turkey hens fed mixtures with raw or extruded linseed.

The aim of the study was to determine the most beneficial proportion of raw linseed in complete feed mixtures for turkey hens on the basis of lipid and redox indicators in the blood. In experiment 1, the turkey hens received the complete mixture with 2%, 4% or 6% linseed. On the basis of the results obtained in experiment 1, we selected the most effective proportion of linseed, which was given to the birds in the group receiving a 4% linseed additive. In experiment 2, the birds were fed mixtures with a 4% addition of raw or extruded linseed. The use of 4% raw linseed was found to improve production effects (improvement of weight gain, and lower feed conversion ratios), while extruded linseed in the diet of turkey hens did not affect growth performance. The use of linseed (4% and 6%) as a feed component for turkey hens led to an increase in indicators of antioxidant potential, that is the total antioxidant potential of the plasma, vitamins E and C, bilirubin and creatinine. A benefit resulting from the use of linseed, particularly in the amounts of 2% and 4% was a marked improvement in lipid indicators in the blood. The reduced percentage of unsaturated fatty acids (n-3) following the use of extruded linseed resulted in a decrease in lipid peroxidation (lower content of malondialdehyde, superoxide and vitamins C and E in the blood). The most effective dose and form of linseed in the diet of turkey hens is 4% raw linseed.

The effect of different dietary levels of dl-methionine and dl-methionine hydroxy analogue on the antioxidant and immune status of young turkeys.

The hypothesis postulating that the antioxidant and immunological effects of dietary methionine (Met) in young turkeys (1-8 weeks of age) can be differentiated by level and source of Met was investigated in this study. A total of 544 female Hybrid Converter turkeys were divided into four groups and fed diets in which Met content was tailored through supplementation with dl-methionine (dl-Met) or dl-methionine hydroxy analogue (MHA) to levels recommended by NRC (1994) (Groups dl-MetL and MHAL) and exceeding them by 50% (Groups dl-MetH and MHAH). Regardless of its source, the increased dietary Met content led to significantly higher body weight gains but had no effect on feed conversion rates. Moreover, an increased Met content lowered lipid peroxide concentrations in breast meat and increased selected indicators of the plasma antioxidant status like uric acid levels, activity of superoxide dismutase (SOD), glutathione (GSH) concentrations, the ferric-reducing ability of plasma (FRAP), increased immunoglobulin A (IgA) plasma levels and decreased interleukin 6 levels. In comparison with dl-Met, MHA decreased the activities of SOD and catalase, and GSH concentrations in plasma. A dosage by source interaction revealed that the lower MHA content was associated with the lowest plasma GSH concentrations, FRAP values and activities of SOD and catalase. The higher dietary MHA level resulted for most parameters similar values, except for a decrease in lipid peroxide concentrations and an increase in plasma IgA levels. It can be concluded that an increased dietary dl-Met and MHA content (about 150% of the recommendations given by NRC 1994) not only increased the growth rate of young turkeys but also improved their antioxidant status. MHA appears to be a less desirable source of dietary Met for young turkeys when the inclusion level of Met matches the current recommendations. Therefore, a further debate is needed to establish the dietary requirements for Met in poultry.

The effect of DL-, L-isomers and DL-hydroxy analog administered at 2 levels as dietary sources of methionine on the metabolic and antioxidant parameters and growth performance of turkeys.

A hypothesis was verified that dietary methionine (Met) improves the growth and antioxidant status of turkeys, and that its effects depend on dietary inclusion levels and sources. A total of 816 female Hybrid Converter turkeys was fed wheat-soybean meal-based diets supplemented with 3 sources of Met: DL-, L-isomers and DL-hydroxy analog (DLM, LM, and MHA, respectively). In 4 4-week periods (from one to 16 wk of age), dietary Met content corresponded to NRC (1994) recommendations or was increased by approximately 50% (in one to 8 wk by 44 to 46% and in 9 to 16 wk by 55 to 56% vs. the NRC guidelines) to match the recommendations of some breeding companies. Increased Met content resulted in higher final body weights of turkeys (P = 0.002), an improved feed conversion ratio (P = 0.049), increased total glutathione concentration and ferric reducing ability of plasma (FRAP) values, and decreased malondialdehyde (MDA) concentration (all P < 0.001) in the blood plasma of turkeys. In comparison with DLM, LM and MHA contributed to an increase in plasma glutathione concentration (P = 0.001), a decrease in plasma triacylglycerol (P = 0.003) and uric acid (P = 0.001) concentrations, and a decrease in liver MDA (P = 0.001) levels. A decrease in plasma MDA (vs. DLM) and lipid peroxides (LOOH) (vs. DLM and LM) concentrations as well as a decrease in plasma superoxide dismutase (SOD) activity (vs. DLM and LM) also were noted in the MHA treatment (P = 0.016, P = 0.001 and P = 0.011, respectively). In conclusion, the results of the study indicate that the antioxidant status of turkeys could be affected by dietary Met levels and sources. The dietary Met content increased by 50% relative to NRC recommendations, improved the growth performance of turkeys, and strengthened their antioxidant defense system. In comparison with DLM, LM and MHA could be considered positive nutritional factors as manifested by a beneficial decrease in plasma and hepatic MDA concentrations as well as an increase in plasma glutathione levels, and the effect of MHA was more pronounced.

Enhanced GABAergic inhibition in the premammillary nucleus of photorefractory turkey hens via GABAA receptor upregulation.

The premammillary nucleus (PMM) of the turkey mediobasal hypothalamus, where dopamine-melatonin (DA-Mel) neurons are localized, is a site for photoreception and photoperiodic time measurement, which is essential for the initiation of avian reproductive seasonality. In addition, this area could also be responsible for the onset and maintenance of photorefractoriness at the end of the breeding season due to the enhanced inhibitory effect of γ-aminobutyric acid (GABA). GABA is an inhibitory neurotransmitter in the central nervous system which interferes with the photosexual response in the turkey, a seasonally breeding bird. Here, we further characterized the GABAA receptor subunits in the PMM DA-Mel neurons related to reproductive seasonality and the onset of photorefractoriness. GABAA receptor subunits and GABA synthesis enzymes in the PMM of photosensitive and photorefractory turkey hens were identified using real-time qRT-PCR. The upregulation of GABAA receptor α1-3, ß2-3, γ1-3, ρ1-3, δ, and θ mRNA expression were observed in the PMM of photorefractory birds when compared to those of photosensitive ones while there is no change observed in the GABA synthesis enzymes, glutamate decarboxylase 1 and 2. Those upregulated GABAA receptor subunits were further examined using immunohistochemical staining and they appeared to be co-localized within the PMM DA-Mel neurons. The upregulation of GABAA receptor subunits observed in the PMM of photorefractory birds coincides with a lack of responsiveness to a light stimulus provided during the photosensitive phase. This is supported by the absence of c-fos induction and TH upregulation in the PMM and a subsequence inhibition of c-fos and GnRH-I expression in the nucleus commissurae pallii. The augmented GABAA receptor subunits expression may mediate an enhancement of inhibitory GABAergic neurotransmission and the subsequent interference with the photosexual response. This could contribute to the state of photorefractoriness and the termination of breeding activities in the turkey, a temperate zone bird.

Metronidazole pharmacokinetics during rapid growth in turkeys - relation to changes in haemodynamics and drug metabolism.

Whereas interspecies variation in pharmacokinetics is a commonly investigated issue, variations in drug kinetics within a species are less documented. The aim of the study was to assess the influence of age-related changes in haemodynamics on the pharmacokinetics of metronidazole (MTZ) and its hydroxy metabolite (MTZ-OH) in turkeys. MTZ was administered intravenously and orally at a dose of 25 mg/kg. Plasma drug and metabolite concentrations were assessed by high-performance liquid chromatography, and pharmacokinetic parameters were calculated by noncompartmental analysis. Haemodynamic parameters (heart rate, stroke volume, cardiac output) were assessed by echocardiography and extraction ratio for MTZ was calculated based on total body clearance (ClB ). Between the 5th and 15th week of age, ClB of MTZ decreased from 3.6 to 1.2 mL/min/kg causing a twofold increase in the mean residence time (MRT) and elimination half-life (T1/2el ). The MTZ-OH production decreased threefold and its MRT and T1/2el increased. Although heart rate significantly decreased with age, cardiac output increased. Extraction ratio was low in all age groups. It is concluded that significant age-dependent decrease in ClB of MTZ in turkeys resulted from decreased perfusion of the clearing organs and their reduced metabolic capacity. This phenomenon is probably species specific and may apply to other therapeutic agents.

Antioxidant status of turkey breast meat and blood after feeding a diet enriched with histidine.

The objective of this study was to investigate the effects of 1) spray dried blood cells rich in histidine and 2) pure histidine added to feed on the antioxidant status and concentration of carnosine related components in the blood and breast meat of female turkeys. The experiment was performed on 168 Big7 turkey females randomly assigned to 3 dietary treatments: control; control with the addition of 0.18% L-histidine (His); and control with the addition of spray dried blood cells (SDBC). Birds were raised for 103 d on a floor with sawdust litter, with drinking water and feed ad libitum. The antioxidant status of blood plasma and breast muscle was analyzed by ferric reducing ability (FRAP) and by 2,2-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging ability. The activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) was analyzed in the blood and breast meat, with the content of carnosine and anserine quantified by HPLC. Proximate analysis as well as amino acid profiling were carried out for the feed and breast muscles. Growth performance parameters also were calculated. Histidine supplementation of the turkey diet resulted in increased DPPH radical scavenging capacity in the breast muscles and blood, but did not result in higher histidine dipeptide concentrations. The enzymatic antioxidant system of turkey blood was affected by the diet with SDBC. In the plasma, the SDBC addition increased both SOD and GPx activity, and decreased GPx activity in the erythrocytes. Feeding turkeys with an SDBC containing diet increased BW and the content of isoleucine and valine in breast muscles.

Proteomic analysis of white and yellow seminal plasma in turkeys (Meleagris gallopavo).

Yellow semen syndrome (YSS) is endemic within domestic turkey populations. Yellow semen is of lower quality and, when used for insemination, results in reduced fertility and hatchability. Little is known about the etiology of YSS. The aim of this study was to compare the proteome of white and yellow seminal plasma of turkeys using 1) 2-dimensional difference gel electrophoresis (2D-DIGE) to quantify seminal plasma proteins and 2) matrix-assisted laser desorption/ionization mass spectrometry to identify the proteins that are differentially abundant in white and yellow seminal plasma. A total of 49 protein spots (30 upregulated and 19 downregulated) were differentially expressed in yellow seminal plasma compared with white seminal plasma. Transthyretin and serum albumin-like showed a 3-fold increase in seminal plasma from males with YSS, and the latter was validated using Western blot analysis. A 3-fold increase was observed for hemopexin-like and immunoglobulin light chain V-J-C region. Pantetheinase-like showed a 1.3-fold increase. Ovotransferrin, hepatocyte growth factor activator, cysteine-rich secretory protein 3-like, and ferritin heavy chain-like showed a significant decrease (at least a 1.3-fold decrease) in yellow semen. Further studies are necessary to evaluate the precise function of the above-mentioned proteins in YSS and to establish quality markers of turkey semen to predict the reproductive potential of individual turkeys.

Concentrations of the adrenocorticotropic hormone, corticosterone and sex steroid hormones and the expression of the androgen receptor in the pituitary and adrenal glands of male turkeys (Meleagris gallopavo) during growth and development.

Androgens take part in the regulation of puberty and promote growth and development. They play their biological role by binding to a specific androgen receptor (AR). The aim of this study was to evaluate the expression of AR mRNA and protein in the pituitary and adrenal glands, to localize AR protein in luteinizing hormone (LH)-producing pituitary and adrenocortical cells, to determine plasma concentrations of adrenocorticotropic hormone (ACTH) and corticosterone and the concentrations of corticosterone, testosterone (T), androstenedione (A4) and oestradiol (E2) in the adrenal glands of male turkeys at the age of 4, 8, 12, 16, 20, 24 and 28weeks. The concentrations of hormones and the expression of AR varied during development. The expression of AR mRNA and protein in pituitary increased during the growth. The increase of AR mRNA levels in pituitary occurred earlier than increase of AR protein. The percentage of pituitary cells expressing ARs in the population of LH-secreting cells increased in week 20. It suggests that AR expression in LH-producing pituitary cells is determined by the phase of development. The drop in adrenal AR mRNA and protein expression was accompanied by an increase in the concentrations of adrenal androgens. Those results could point to the presence of a compensatory mechanism that enables turkeys to avoid the potentially detrimental effects of high androgen concentrations. Our results will expand our knowledge of the role of steroids in the development of the reproductive system of turkeys from the first month of age until maturity.

Expression of the androgen receptor in the testes and the concentrations of gonadotropins and sex steroid hormones in male turkeys (Meleagris gallopavo) during growth and development.

Androgens, including testosterone (T) and androstenedione (A4), are essential for puberty, fertility and sexual functions. The biological activity of those hormones is mediated via the androgen receptor (AR). The regulation of androgen action in birds is poorly understood. Therefore, the present study analysed mRNA and protein expression of AR in the testes, plasma concentrations of the luteinizing hormone (LH), follicle-stimulating hormone (FSH), T, A4 and oestradiol (E2), as well as the levels of T, A4 and E2 in testicular homogenates of male turkeys (Meleagris gallopavo) at the age of 4, 8, 12, 16, 20, 24 and 28weeks. Plasma concentrations of LH and FSH, as well as plasma and testicular levels of T and A4 began to increase at 20weeks of age. The lowest plasma levels of E2 were noted at 20weeks relative to other growth stages. The 20th week of life seems to be the key phase in the development of the reproductive system of turkeys. The AR protein was found in the nuclei of testicular cells in all examined growth stages. Higher expression of AR protein in the testes beginning at 20weeks of age was accompanied by high plasma concentrations of LH and high plasma and testicular levels of androgens. This relationship seems to be necessary to regulate male sexual function.

Kink characterization and modeling in transmembrane protein structures.

Kinks have been observed to provide important functional and structural features for membrane proteins. Despite their ubiquity in membrane proteins, and their perceived importance, no protein modeling methods explicitly considers kinks. In spite of the limited data for transmembrane proteins, we were able to develop a knowledge-based modeling method for introducing kinks, which we demonstrate can be exploited in modeling approaches to improve the quality of models. The work entailed a thorough analysis of the available high resolution membrane protein structures, concomitantly demonstrating the complexity of the structural considerations for kink prediction. Furthermore, our results indicate that there are systematic and significant differences in the sequence as well as the structural environment between kinked and nonkinked transmembrane helices. To the best of our knowledge, we are reporting a method for modeling kinks for the first time.

Heterologous expression and functional characterization of avian mu-class glutathione S-transferases.

Hepatic glutathione S-transferases (GSTs: EC2.5.1.1.8) catalyze the detoxification of reactive electrophilic compounds, many of which are toxic and carcinogenic intermediates, via conjugation with the endogenous tripeptide glutathione (GSH). Glutathione S-transferase (GST)-mediated detoxification is a critical determinant of species susceptibility to the toxic and carcinogenic mycotoxin aflatoxin B1 (AFB1), which in resistant animals efficiently detoxifies the toxic intermediate produced by hepatic cytochrome P450 bioactivation, the exo-AFB1-8,9-epoxide (AFBO). Domestic turkeys (Meleagris gallopavo) are one of the most sensitive animals known to AFB1, a condition associated with a deficiency of hepatic GST-mediated detoxification of AFBO. We have recently shown that unlike their domestic counterparts, wild turkeys (Meleagris gallopavo silvestris), which are relatively resistant, express hepatic GST-mediated detoxification activity toward AFBO. Because of the importance of GSTs in species susceptibility, and to explore possible GST classes involved in AFB1 detoxification, we amplified, cloned, expressed and functionally characterized the hepatic mu-class GSTs tGSTM3 (GenBank accession no. JF340152), tGSTM4 (JF340153) from domestic turkeys, and a GSTM4 variant (ewGSTM4, JF340154) from Eastern wild turkeys. Predicted molecular masses of tGSTM3 and two tGSTM4 variants were 25.6 and 25.8kDa, respectively. Multiple sequence comparisons revealed four GSTM motifs and the mu-loop in both proteins. tGSTM4 has 89% amino acid sequence identity to chicken GSTM2, while tGSTM3 has 73% sequence identity to human GSTM3 (hGSTM3). Specific activities of Escherichia coli-expressed tGSTM3 toward 1-chloro-2,4-dinitrobenzene (CDNB) and peroxidase activity toward cumene hydroperoxide were five-fold greater than tGSTM4 while tGSTM4 possessed more than three-fold greater activity toward 1,2-dichloro-4-nitrobenzene (DCNB). The two enzymes displayed equal activity toward ethacrynic acid (ECA). However, none of the GSTM proteins had AFBO detoxification capability, in contrast to recombinant alpha-class GSTs shown in our recent study to possess this important activity. In total, our data indicate that although turkey hepatic GSTMs may contribute to xenobiotic detoxification, they probably play no role in detoxification of AFBO in the liver.

Volatile gas concentrations in turkey houses estimated by Fourier Transform Infrared Spectroscopy (FTIR).

1. The aim of the present study was to estimate gas concentrations in commercial turkey houses by Fourier Transform Infrared Spectroscopy (FTIR). 2. The experiment was conducted in 5 buildings of a commercial turkey farm. The measurements of gases were carried out every 3 weeks of the growth cycle. 3. The results demonstrate that ammonia and carbon dioxide are the prevalent gases released during the entire production cycle in turkey houses. The mean concentrations of the above compounds ranged between 4-31 ppm and 220-2058 ppm, respectively. Thiols, nitriles, amines, aldehydes, hydrocarbons and other organic and inorganic compounds also occurred in turkey houses, but they were emitted periodically and their mean concentrations were significantly lower in comparison with CO2 and NH3. 4. Lower ventilation ratio and higher moisture of excreta in the first half of the growth period accelerated the release of some gases, whereas gradual faeces and urine accumulation contributed to an increase in the concentration of selected organic compounds. 5. A portable FTIR analyser is a useful device for measuring gas concentrations in commercial turkey farms, and it supports determinations of tolerable emission limits in turkey production.

Effects of 17ß-estradiol on turkey myogenic satellite cell proliferation, differentiation, and expression of glypican-1, MyoD and myogenin.

The hypothesis of this study was that 17ß-estradiol (estradiol) stimulates turkey skeletal muscle growth by influencing myogenic satellite cell proliferation, differentiation, and the gene expression of selected proteins important in regulating growth and development. Increasing levels of estradiol were administered in basal medium containing additional nutrients. Female-derived pectoralis major (PM) satellite cell proliferation was stimulated by estradiol at a level of 10(-9)M following 4days of treatment. Male PM and biceps femoris (BF) satellite cell proliferation was increased at 10(-12)M estradiol. Turkey embryonic myoblast proliferation, however, decreased with 10(-9)M and 10(-5)M estradiol following 3days under these conditions. Estradiol had no effect on the differentiation of any of the 4 groups of cells. Likewise, glypican-1 expression was unaffected by estradiol treatment. MyoD expression decreased in male PM but not BF cells. MyoD expression in female PM cells and embryonic myoblasts were also unaffected by estradiol administration. Estradiol decreased myogenin expression in male satellite cells, but had no effect on female cells. There was a slight decrease in myogenin expression in embryonic myoblasts. The results demonstrate a direct effect of estradiol on avian satellite cell proliferation independent of glypican-1, and decreased expression of MyoD and myogenin in some myogenic cells, coinciding with increased cellular proliferation.

Molecular cloning and tissue-specific expression of Toll-like receptor 5 gene from turkeys.

Toll-like receptors (TLRs), a family of transmembrane and cytosolic proteins, detect microbial patterns, initiating innate immune responses in various organisms. Although they are abundant, genetic characterization and functional differences of TLRs in economically important avian species such as chickens and turkeys have not been investigated in detail. In this study, the putative TLR5 coding region from turkey genome was sequenced, and its homology to other vertebrate species was analyzed. Secondary structure analysis revealed protein motifs typical of the chicken TLR5 protein structure, with 97% amino acid identity between them. mRNA expression profiling in adult turkeys revealed abundant TLR5 expression in a broad range of tissues. Stimulation with the TLR5 ligand flagellin resulted in the production of the inflammatory mediators interleukin (IL)-1beta, IL-6, and nitric oxide in peripheral blood mononuclear cells. To our knowledge, this is the first complete turkey TLR5 coding DNA sequence reported in sequence databases.