Anatomical and histologic pathology induced by cervical dislocation following blunt head trauma for on-farm euthanasia of poultry

The selection of an optimal method for on-farm euthanasia of poultry in cases of emergency killing is still under debate. The preferred approach would spare pain and suffering and would ensure proper stunning as well as rapid death. Here, the effects and pathological lesions induced by blunt trauma to the head followed by cervical dislocation were studied in chickens and turkeys of different weight groups of up to 20 kg. To allow for feasible on-farm execution, including birds heavier than 3 kg, a percussive blow to the head with subsequent manual or mechanical cervical dislocation using a nonpenetrating forceps was employed. Systematic macroscopic, radiographic, and histopathologic examinations were performed with special attention to anatomical structures essential for consciousness and vital functions. The 2 traumatic impacts resulted not only in massive subdural hematomas, cortical brain damage, dissecting vertebral bone fractures, and a disruption of the cervical spinal cord, but also severe lacerations of the medulla oblongata area of the brain stem. The lesions were suggestive of immediate loss of consciousness and indicative of immediate and irreversible loss of central regulation of breathing and heart function. Moreover, the results were largely independent of the weight class examined, indicating that from a pathology perspective the methods used may be suitable for humane euthanasia of poultry of up to 20 kg in live weight.     

The effect of maternal vitamin D source on broiler hatching egg quality,hatchability, and progeny bone mineral density and performance

Vitamin D is involved in calcium metabolism as well as bone and shell quality, and is therefore important to broiler breeders. In this research we investigated the effects of maternal dietary 25-OH vitamin D₃ on broiler breeder egg quality and hatchability, as well as on progeny bone mineral density and performance. In a field study, all hens were fed 3,000 IU of vitamin D₃ (D) per kilogram of complete feed; in addition half of the hens also received 34.5 µg of 25-OH vitamin D₃ per liter in the drinking water (25OHD). Eggs from each treatment group were incubated and hatched; chicks were fed a common diet and grown to 41 d of age. Eggs from hens in the 25OHD treatment had a nearly 30% reduction in early embryo mortality. However, a larger egg size resulted in greater chick BW for the D chicks, although this did not affect broiler production performance. Broilers from the maternal 25OHD treatment had a lower FCR during the grower phase. Unexpectedly, chick plasma 25-OH vitamin D₃ was only greater for the maternal 25OHD treatment at 4 d of age, but not at hatch, 2, 6, 8, 10, 12, or 14 d of age. Maternal vitamin D₃ source did not affect progeny 41-d bone mineral density. Maternal 25-OH vitamin D₃ had a protective effect on the growing embryo, reducing early embryonic mortality, with minimal effects on progeny performance and bone mineral density to processing at 41 d of age. The previously reported effects of 25-OH vitamin D₃ on increasing broiler performance and breast yield seem to be dependent on supplementation of the broiler diet; a carry-over effect of maternal supplementation is insufficient to achieve these effects.     

AA父母代肉鸡产蛋曲线的数学模型分析

根据AA父母代肉鸡第25~65周龄的群体产蛋记录,用伍德模型、杨宁模型和分室模型拟合了入舍母鸡的单周、双周产蛋曲线。三种模型拟合的R2值分别为:伍德模型0.807 14(单周),0.862 31(双周);杨宁模型0.995 33(单周),0.979 41(双周);分室模型0.995 53(单周),0.99205(双周)。分室模型最适于肉种鸡群产蛋曲线的拟合。     

Influences of breeder age and fasting after hatching on the performance of broilers

In this trial, we assessed the effects of 2 different ages of breeders and of 2 periods of fasting posthatching on the performance of broilers up to 42 d of age. Male broilers from breeders of different ages (30 and 60 wk) were subjected to an experimental design with 4 treatments: 1) T1, chicks not subjected to fasting, from 30-wk-old breeders; 2) T2, chicks not subjected to fasting, from 60-wk-old breeders; 3) T3, chicks subjected to a 12-h fast, from 30-wk-old breeders; and 4) T4, chicks subjected to a 12-h fast, from 60-wk-old breeders. At the end of the trial, feed intake was greater for the chicks from older breeders. Fasting had a negative influence on feed intake in the period from 0 to 10 d of age. The birds from older breeders had a greater BW gain from 21 to 35 d of age when they were not subjected to a fasting period, but when birds were subjected to a fasting period, no differences between broiler breeder ages were observed on BW gain. Fasting did not exert a significant effect on the BW of the birds. Feed conversion was not influenced by the age of the breeders or by fasting.     

Suitability of poultry litter ash as a feed supplement for broiler chickens

An experiment was conducted to evaluate poultry litter ash (PLA) at graded levels (0, 25, 50, 75, and 100%) as a dietary substitute for dicalcium phosphate (dicalP) for broiler chickens, where PLA was substituted for dicalP on a wt/wt basis. A decreased BW gain was observed at 21 d from PLA at the 100% substitution rate when compared with the 25% substitution rate. No effects on BW gain, feed consumption, or FCR were incurred by study termination at 41 d, and the 100% substitution rate of dicalP did not cause any detrimental effects on the live performance in market age broilers. Although femur ash percentages decreased with increasing levels of PLA, bone integrity was not compromised by the addition of PLA to the diet. Dry matter digestibility of dietary Ca (26.32–58.65%) and P (30.23–42.68%) increased with increasing levels of PLA (0–100%), respectively, inferring that the Ca and P component of the diet was more efficiently used as the level of PLA increased. In conclusion, PLA resulting from the combustion of poultry litter can be used as a P and Ca source for broilers.     

Effect of vitamins,protein level and probiotics on immune response of moulted male broiler breeders

This study was planned to investigate the comparative effect of vitamins C (L‐ascorbic acid), E (DL‐α‐tocopherol acetate), probiotics, lower than normal protein level (14%) and combination of these treatments on immune response of male broiler breeders after zinc‐induced moulting. One hundred and eighty birds at the age of 65 weeks were induced to moult by mixing zinc oxide (ZnO) in feed at the rate 3000 IU/kg of feed. Upon completion of moulting, birds were divided into six groups (five replicates per group) in a completely randomized design and were fed vitamin C (500 IU/kg), vitamin E (100 IU/kg), lower protein level, probiotics (50 mg/l), and a combination of these components, while one group was kept as control. After completion of moulting phase (5 weeks), the treatment effects were tested as in vitro macrophages engulfment percentage, nitric oxide (NO) production, serum antibody titres against Newcastle disease (ND) and infectious bronchitis (IB). The results showed that in vitro macrophage engulfment percentage in unopsonized conditions was significantly higher in vitamin E‐supplemented group. In addition, in opsonized condition, the macrophage engulfment percentage was significantly higher in both vitamin E‐ and C‐supplemented groups. The NO (opsonized and unopsonized) production and antibody titre against ND and IB were significantly higher in vitamin E‐supplemented group. It was concluded that vitamin E is a better option for enhanced immune response in broiler breeders after zinc‐induced moulting.     

脱氢表雄酮对AA肉种鸡生产性能和肌纤维发育的影响

为探讨母源性添加DHEA对子生理机能影响的母体效应机制,本试验选用100羽16周龄AA种母鸡随机分成对照组、低剂量试验组、中剂量试验组和高剂量试验组,每组25只。于34周龄开始在饲料中添加DHEA,剂量分别为0、25、50和100 mg.kg-1,连续饲喂7周,期间记录每天的产蛋数并称重。在试验的第49天禁饲12 h,宰杀各组鸡。采集血液、腹脂、左侧胸肌和腿肌,计算产蛋率、平均蛋重、腹脂率、相对胸肌重和相对腿肌重。测定血清中尿酸(UA)和肌酐(Cr)含量。取腿肌和胸肌制作冰冻组织切片,测定肌纤维直径和密度。结果表明,与对照组相比,低剂量组母鸡产蛋率极显著升高(P0.01),中剂量组和高剂量组则极显著降低(P0.01);试验组平均蛋重差异不显著(P0.05);高剂量组母鸡的相对腿肌重显著升高(P0.05),而低剂量组和中剂量组差异不显著(P0.05);试验组腹脂率和相对胸肌重量差异不显著(P0.05);低剂量组血清UA含量极显著升高(P0.01),中剂量组有升高趋势,高剂量组显著升高(P0.05);中剂量组和高剂量组血清Cr含量没有显著变化(P0.05),低剂量组极显著升高(P0.01);3个剂量组AA肉种鸡胸肌肌纤维直径和密度均没有显著变化(P0.05);低剂量组腿肌肌纤维直径没有显著变化(P0.05),中剂量组显著减小(P0.05),高剂量组极显著减小(P0.01);低剂量组腿肌肌纤维密度没有显著变化(P0.05),中剂量组显著增大(P0.05),高剂量组极显著增大(P0.01)。     

三黄种鸡产蛋期的生长模型的建立与分析

为了解三黄鸡产蛋期的生长发育规律,运用Logistic、Gompertz和von Bertalanffy 3种曲线模型分别对5～16月龄的三黄鸡体重数据进行拟合和分析。结果表明:3种模型均能很好地模拟三黄鸡产蛋期的生长情况,以Logistic模型拟合效果最佳。应用3种模型对三黄鸡产蛋期进行生长曲线拟合和分析是可行的。