Differences in aromatase expression and steroid hormone concentrations in the reproductive tissues of male domestic turkeys (Meleagris gallopavo) with white and yellow semen

ABSTRACT

1. To show hormonal differences between male turkeys with yellow semen syndrome (YSS) and white, normal semen (WNS), the expression of aromatase, oestrogen receptor α (ERα), and oestrogen receptor β (ERβ) as well as testosterone and oestradiol concentrations in YSS and WNS testes, epididymis, and ductus deferens were examined.

2. To measure gene expression levels of aromatase and oestrogen receptors (ERs), three complementary techniques (real-time PCR, Western blot, and immunohistochemistry) were used, whereas steroid hormone levels were determined radio-immunologically.

3. Upregulation of aromatase and ERα mRNAs in YSS testes (P < 0.05; P < 0.01), epididymis (P < 0.001; P < 0.001), and ductus deferens (P < 0.05; P < 0.01) compared to those of WNS tissues was detected. Significant increases in the levels of aromatase and ERα proteins were detected in YSS testes (P < 0.001; P < 0.05), epididymis (P < 0.001; P < 0.001), and ductus deferens (P < 0.001; P < 0.05). The expression of ERβ mRNA and protein level was upregulated in the testes (P < 0.05; P < 0.01) and epididymis (P < 0.001; P < 0.01) but not in ductus deferens where it was downregulated (P < 0.01; P < 0.01). Increased intensity of immunoreactive proteins in YSS versus WNS reproductive tissues corroborated gene expression results.

4. Testosterone concentration diminished in YSS epididymis (P < 0.05) and ductus deferens (P < 0.05), but not in the testes, remaining at high level (P < 0.05) compared to WNS values. Concomitantly, increased oestradiol concentration was found in YSS testes (P < 0.05) and epididymis (P < 0.05) but decreased in the ductus deferens (P < 0.05).

5. From the published literature, this study is the first to demonstrate the ability for androgen aromatisation in the turkey reproductive tissues and to show the cellular targets for locally produced oestrogens. The data suggested that the androgen/oestrogen ratio is a mechanistic basis for amplification of differences between turkeys with white and yellow semen and that these results can have a relevance in applied sciences to widen the knowledge on domestic bird reproduction.     

Morphology and chemical composition of turkey eggs

The objective of this study was to evaluate selected morphological characteristics and the chemical composition of turkey eggs of different weight classes. The percentage of eggs weighing ≥100 g increased to 46.66% in wk 23. Eggs weighing 95 and 110 g had lower yolk content (3.05 and 4.86%) and higher albumen content (by 3.16 and 5.21%) compared with eggs weighing 80 g. The total protein content of the albumen increased (from 9.93 to 10.71%) and the water content of the albumen decreased (from 88.30 to 87.59%) with an increase in egg weight. Albumen weight per gram of yolk increased from 1.87 to between 2.18 and 2.42 g in larger eggs. The energy density of the egg decreased from 5.68 to 4.90 kJ/g with an increase in egg weight, and the energy density of the yolk remained at a similar level in all egg weight classes. The other analyzed yolk and shell parameters were not affected by egg weight. The highest energy and total protein content of the yolk was observed in wk 14 of the laying season. No correlations were found between the progress of the laying cycle and eggshell percentage and the water content of the yolk. The values of the remaining egg parameters varied over the laying season.     

The effect of crate height on the behavior of female turkeys during commercial pre‐slaughter transportation

Limited information is available on suitable height of transport crates for turkeys. We compared behaviors and physiological indicators of four groups of 10 female turkeys each confined in either conventional (38.5 cm height) or experimental (77 cm height) crates during six commercial pre‐slaughter transportations for 86 km (76 ± 4 min) along two tracts with one‐lane streets, crossroads, bends, roundabouts (S1 and S2) and a highway tract (H) between S1 and S2. Only 36% of birds in the higher crates maintained a standing position. In conventional versus experimental crates, the frequency of rising attempts was five/bird/hour versus less than one/bird/hour, while wing flapping was seven/bird/hour versus 20/bird/hour, and balance loss was one versus four/bird/hour. The behaviors of both groups differed significantly according to the route tract, with a lower frequency of stress‐related behaviors at H. No scratches, fractures or hematomas were detected in any birds after transportation. Crate height had no significant effect on hemato‐biochemical markers. These results suggest that crates enabling a standing position may increase potentially dangerous behaviors. Moreover, busy and curvy routes should be avoided, as they may contribute to increasing the frequency of stress‐related behaviors.     

火鸡传染性鼻气管炎病毒对鸡致病性的研究

作者对火鸡传染性鼻气管炎病毒（ARTV）对鸡致病性进行了初步的研究，发现大肠杆菌在本病的发生过程中起着重要的协同作用。首先对鸡的肝、肾进行攻毒，然后分离病毒，经鸡胚多次传代后，鸡胚出现矮小，头部出血，有时全身出血。取鸡胚尿囊液，经负染，在电子显微镜下观察发现有密集的呈球形的病毒颗粒。     

鸡马立克火鸡疱疹病毒(Fc-126株)的标准化研究 VI.HVT克隆株的稳定性、保存期测定及田间试验效果

对ＨＶＴ克隆株进行了稳定性测定，结果表明克隆株稀释后室温存放１小时，病毒滴度损失不超过３０％，符合有关规定。在－７０℃和－２０℃下保存，克隆株保存期分别至少可达到３年和２．５年。用克隆株试制的３批产品在野外使用效果良好，无任何不良反应。     

饲粮能量和蛋白质水平对21~56日龄青铜火鸡生长性能 和血清生化指标的影响

为研究饲粮能量和蛋白质水平对21 ~ 56日龄青铜火鸡雏鸡生长性能和血清生化指标的影响，试验采用2 × 3双因子试验设计，分别为2个能量水平（12.13 和12.53 MJ·kg^-1）和3个蛋白质水平（22%、24%和26%）；选体重相近的青铜火鸡雏鸡180只，随机分为6组，每组5个重复，每个重复6只；常规饲养至20日龄，21日龄正式开始试验，为期35 d。结果表明：（1）饲粮蛋白质水平显著影响56 d火鸡体重、平均日增重（ADG）和料重比（F/G），蛋白质水平为26%组56 d火鸡体重和ADG显著高于22%组(P < 0.05)，蛋白质水平为26%组火鸡F/G显著低于22%组（P < 0.05）；饲粮能量和蛋白质水平对56 d火鸡体重和ADG有显著的交互作用（P < 0.05)。（2）饲粮蛋白质水平对血清尿素（UA）和总胆固醇（TC）含量有显著性影响，26%组雏火鸡血清中UA含量显著高于22%和24%组（P < 0.05），蛋白质水平为22%组血清TC含量显著高于26%组（P < 0.05）。饲粮能量和蛋白质水平对血清中球蛋白（GLB）含量有显著的交互作用（P < 0.05）。（3）饲粮能量水平对血清中类胰岛素生长因子1（IGF-1）的含量有显著性影响(P < 0.01)，能量水平为12.53 MJ·kg^-1组血清中IGF-1的含量显著高于12.13 MJ·kg^-1组；饲粮蛋白质水平极显著地影响血清中生长激素（GH）含量，蛋白质水平为22%组血清中GH含量显著高于24%和26%组(P < 0.01)；饲粮能量和蛋白质水平对血清中GH含量有显著的交互作用(P < 0.05)。（4）饲粮能量水平为12.13 MJ·kg^-1，蛋白质水平为26%时，火鸡的经济效益最好。综上所述，本试验条件下，21 ~ 56日龄青铜火鸡最适宜的饲粮能量水平为12.13 MJ·kg^-1，蛋白质水平为26%。