Influence of sequence length on the response to ahemeral lighting late in lay

1. An experiment is described in which 96 individually‐caged SCWL hens in two rooms were used to investigate the response to changing to a 28‐h cycle using a reverse treatment design.

2. The application of the 28‐h cycle did not affect mean rate of lay but increased mean egg weight and egg output.

3. Grouping the birds according to their preliminary sequence length yielded an interesting outcome. In both rooms, birds with short sequences (≤ 6 eggs) produced significantly more eggs under the 28‐h cycle, while those with long sequences (> 6 eggs) produced marginally fewer eggs. The same trend was also evident with egg output.

4. Changing from 24‐h to 28‐h increased yolk and albumen weights as well as shell quality. However, relative to egg weight, no measurable effect was detected due to light cycle, age or sequence length on yolk and albumen weights.

5. The paper provides new evidence suggesting that long ahemeral cycles could be used to improve egg production as well as shell thickness in flocks with modest rates of lay.     

Comparison of artificial light sources and lighting programmes for laying hens on long ahemeral light cycles

Three lighting treatments were given to laying hens, for which the bright and dim light of 28-h ahemeral light cycles was provided by incandescent (tungsten filament) lamps only or by combinations of tubular fluorescent or compact gas-discharge lamps with incandescent lamps. There were no differences in entrainment (the proportion of eggs laid in 4, 6 or 8 h modal periods) between the three bright:dim treatments. A fourth ahemeral lighting treatment in which the dim lights were extinguished except during a designated work period (09.00 h to 12.00 h daily) was termed bright:dim:dark. Hens given the bright:dim:dark treatment showed an increased entrainment compared with the three bright:dim light treatments. There were no differences (P greater than 0.05) in egg numbers or mean egg weight between all 4 lighting treatments. Birds given the bright:dim:dark treatment tended to have a lower (P greater than 0.05) food intake compared to the three bright:dim treatments.     

The time factor in egg formation for hens exposed to ahemeral light-dark cycles

Three hundred and two White Leghorn pullets were killed at intervals 5 min to 7 h following oviposition. The reproductive tract was then examined and, from the position of the yolk, estimates were made of the mean time spent by the ovum in different parts of the oviduct. Half the birds examined had been kept under 24‐h cycles (14 h light : 10 h dark) and half under 27‐h cycles (14 h light : 13 h dark). Mean intervals from oviposition to ovulation were 24 min and 36 min for birds under 24‐h and 27‐h cycles respectively. The difference between these values can be associated with the different rates of lay of birds under the two treatments. Mean times spent in the upper oviduct and the shell gland were estimated as 5·15 h and 19·76 h for the 24‐h cycles and 5·41 h and 20–70 h for the 27‐h cycles. The increase in albumen weight which has been reported to follow from the use of 27‐h cycles can thus be associated with extra time spent in the magnum. The reported increase in shell weight of 10% is more than would be expected from a 5% increase in time spent in the shell gland.     

Genotypic and phenotypic diversity differences of presumptive commensal and avian pathogenic E. coli

1. The objective of the experiment was to characterise the genotypic and phenotypic differences between presumptive commensal E. coli and avian pathogenic E. coli (APEC) of poultry.

2. DNA was extracted from 65 confirmed APEC E. coli from chicken, 100 presumptive commensal E. coli from healthy turkey and 35 from healthy chicken. Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and virulence factors genotyping was performed to characterise genetic features.

3. Carbon source utilisation and antimicrobial susceptibility tests were performed to characterise phenotypic features of isolates.

4. The genetic divergence between E. coli strains tested by ERIC-PCR profiles and virulence-associated genes showed a clear genetic separation between E. coli APEC and turkey E. coli strains.

5. The carbon utilisation profile of turkey isolates was different from chicken and APEC strains; whereas antimicrobial susceptibility was highest for turkey isolates (53%), and lowest for APEC strains (33.8%).

6. The study showed a significant negative correlation between utilisation of arabitol and adonitol with different virulence determinants tested, which suggests that the ability to utilise some uncommon carbon sources may be used to discriminate between presumptive commensal E. coli and APEC.     

葎草幼苗对盐胁迫响应的性别差异

采用盆栽试验研究了葎草(Humulus scandens)幼苗对盐胁迫响应的生理生化性别差异,测定了不同盐(NaCl)浓度(0、100、200、300mmol·L~(-1))下雌雄植株的单叶面积、气体交换参数、叶水势、叶绿素荧光、叶绿素含量、过氧化氢酶(CAT)和丙二醛(MDA)含量等指标的变化。结果表明,NaCl胁迫后葎草雌雄幼苗的叶干重、净光合速率(P_n)、气孔导度(G_s)、胞间CO_2浓度(C_i)、蒸腾速率(T_r)、叶水势(ψ_w)和CAT均呈逐渐降低的趋势,而气孔限制值(L_s)和MDA逐渐上升,其单叶面积则先升后降。随着NaCl胁迫的递增,雌株的最小荧光(F_o)呈先升后降的变化,最大荧光(_Fm)、可变荧光(F_v)、PSⅡ潜在活性(F_v/F_o)和非光化学淬灭系数(qN)则逐渐递增,光化学淬灭系数(qP)和叶绿素含量却逐渐递减;从总体上看,雄株的表现光合电子传递速率(ETR)、Fm和Fv、最大光化学效率(F_v/F_m)和F_v/F_o也呈上升趋势,qN和qP却呈下降趋势,而叶绿素含量却先升后降。因此,NaCl胁迫影响了葎草雌雄幼苗的单叶面积、叶绿素含量、叶绿素荧光、气体交换、CAT和MDA含量等生理生化特征,但雌雄幼苗对NaCl胁迫的响应存在差异。与雄株相比,雌株对NaCl胁迫更耐受。     

温度对雌雄葎草生理代谢及保护酶系统影响的性别差异

以雌雄异株攀援草本植物葎草为材料,依据野生资源主要分布地域的平均温度,设置3个温度(15, 20, 25 ℃)为变量,通过测定光合指标、代谢指标、抗氧化酶活性指标和细胞膜完整性指标,分析温度对葎草光合作用、呼吸作用及抗逆性影响的生理变化,研究温度对雌雄葎草生理代谢及保护酶系统影响的性别差异。结果表明,温度显著影响葎草叶中的叶绿素含量,P_n和单株生物量随温度下降显著减小(P<0.05),♀株的潜在P_n显著大于♂株(P<0.05);♂株的糖代谢和呼吸作用显著高于♀株(P<0.05),氮代谢性别间无显著差异(P>0.05),温度对可溶性糖(SS)、丙酮酸(PA)含量和硝酸还原酶(NR)有显著影响(P<0.05),随温度下降SS含量逐步增加(P<0.05),NR活性逐步降低(P<0.05),温度对代谢速率影响远大于性别间的差异。温度对SOD和POD活性有极显著影响(P<0.01),对CAT活性有显著影响(P<0.05),随温度降低3种酶活性均不断增加,♀株中SOD和POD含量显著高于♂株(P<0.05),性别间CAT含量无差异。温度对细胞膜完整性物质含量的影响,远大于性别间差异,随温度降低葎草体内H₂O₂、丙二醛(MDA)、脯氨酸(Pro)和可溶性蛋白(SP)含量均显著增加,♂株中H₂O₂和SP含量显著高于♀株(P<0.05),♀株中MDA和Pro含量显著大于♂株。温度对光合作用、呼吸作用、抗氧化酶系统及细胞膜完整性的影响有显著的性别差异,♀株比♂株有更强的适应温度胁迫的生理基础。     

The physiological and biochemical response of standardbred horses to exercise of varying speed and duration

LINDHOLM, ARNE and BENGT SALTIN: The physiological and biochemical response of standardbred horses to exercise of varying speed and duration. Acta vet. scand. 1974, 15, 310–324. — Welltrained standardbred horses were studied to examine the metabolic response to excercise of various speeds and duration. Comparisons between interval (400, 700, 1,000 and 2,000 m) and continuous trotting (1 hr., 2 hrs.) and racing were made.Muscle and rectal temperatures were recorded before and immediately after each work bout. Heart rate was linearly related to trotting speed, and maximal heart rate (240 beats × min.⁻¹) was achieved when trotting at least 700 m at close to maximal speed (12.0–12.5 m×sec.⁻¹).Biopsy specimens from the gluteus medius muscle and venous blood were obtained before and after each work bout.Muscle and blood lactate values were markedly increased first at speeds close to maximal speed (11.4–12.5 m×sec.⁻¹). Trotting 6×700 m at 12.5 m×sec.⁻¹ produced as high muscle and blood lactate values as 23.7 and 19.0 mmol×kg⁻¹ wet weight and l⁻¹, respectively. Corresponding values after a race were about 15 mmol×kg⁻¹ (muscle) and l⁻¹ (blood).Glycogen utilization was related to work intensity and was most pronounced during the first work bouts. At a speed of 12 m×sec.⁻¹ and trotting 2000 m, there was a glycogen utilization of near 12 mmol glucose units × kg⁻¹ × min.⁻¹ wet muscle.It is concluded that interval training over a distance of 700–1000 m repeated 4–6 times with a trotting speed close to maximal speed (11.4–12.5 m×sec.⁻¹) appears to be optimal.ATP; CP; blood lactate; glycogen utilization; heart rate; horse skeletal muscle; muscle lactate; racing training.     

Time of lay in hens exposed to intermittent lighting

1. Two short-term trials are described in which laying hens were exposed to 8 h light followed by 8 one-min pulses of light at hourly intervals followed by 8 h darkness (8L:8i:8D). The effect of varying the intensity of illumination during the one-min pulses and the effect of placing the intermittent lighting before the 8 h photoperiod (8i:8L:8D), were studied. 2. Normal egg production was maintained by the 8L:8i:8D system when the light pulses were at 20 lux, but not at 5 lux. This suggests a minimum threshold for illumination with short light pulses higher than that needed for continuous lighting. 3. Time of lay under 8L:8i:8D was the same as with 8L:16D in relation to the beginning and ending of the 8 h main photoperiod, but with 8i:8L:8D mean time of lay was 2 to 3 h earlier. Thus the hourly pulses caused a phase advance when placed before the normal photoperiod but did not cause a phase delay when placed after the normal photoperiod.     

营养生长期雌雄葎草表观性状对水分胁迫响应的性别差异

通过设置4个水分梯度,对营养生长期的葎草进行干旱胁迫处理,于性别可识别时,测定雌雄单株的根、茎、叶等构件数量性状、鲜重干重及占生物量比例等指标。结果表明,葎草通过显著缩短营养生长持续期应对水分胁迫,雄株比雌株对水分缺乏更加敏感;根首先,叶次之,茎第三对胁迫做出响应;根通过降低自身含水量满足茎、叶对水分的需要,同时茎叶通过减少叶片数与茎分枝数,缩小单叶面积与茎长度,降低单株对水分的消耗;雄株的叶总面积,茎分枝、长度与体积,根长与体积显著低于雌株;水分对各构件鲜重、干重均存在极显著影响,但性别间仅根系生物量存在显著差异;雄株的总生物量显著低于雌株,但性别对构件生物量分配比例无显著影响。通过减少营养生长投入,快速转入生殖生长应对水分胁迫,为葎草种群繁衍与扩展奠定基础。     

Sex-related differences in immune response and survival rate of broiler chickens

In a comparison between male and female broiler chicks, the mortality rate of males was found to be significantly higher than that of females, starting from the second week of age until marketing at 7 or 8 weeks of age. The main causes of death during this period were various infectious diseases. This observation was explained by differences in the activity of humoral and cell-mediated immune responses between the sexes. In tests of antibody responses of young chicks to a variety of antigens (bacterial-E. coli, viral-Newcastle disease virus, and protein antigen-bovine serum albumin), females responded 24-72 h earlier than males and with higher peak antibody titers. In-vitro proliferation of T-lymphocytes to purified protein derivative and E. coli showed an earlier and greater response in females. The correlation between immune responsiveness and survival, as tested by challenging vaccinated chicks with pathogenic E. coli, showed a significantly higher mortality rate in vaccinated males, that was correlated with their lower antibody titer. We concluded, therefore, that sex-related differences in mortality rates of broiler chicks may result from a less efficient immune response in males.     

速度赛马粪便微生物种群差异的研究

为筛选提高赛马竞技成绩的有益微生物,试验比较现役纯血速度赛马粪便微生物群落多样性及丰度差异.选择休赛一周的现役纯血马9匹,按比赛成绩分为A (16.8 m/s)、B(16.4 m/s)、C(16.3m/s)3组.收集新鲜粪便样本,提取粪便样本菌群DNA,对微生物16S rDNA的V3～V4区序列Illumina测序.结...     

Host differences in response to trickle infection with Fasciola gigantica in buffalo, Ongole and Bali calves

Progressive weight gain, faecal egg counts, packed cell volume, percent eosinophils in blood, serum antibody and serum levels of glutamate dehydrogenase and gamma-glutamyl transpeptidase were recorded in seven swamp buffalo (Bubalis bubalis), 7 Ongole (Bos indicus) and four Bali calves (Bos sundiacus) which were infected orally with 15 metacercariae of Fasciola gigantica twice weekly for 32 weeks. Similar observations were made on four buffalo, 4 Ongole calves and 3 Bali calves maintained fluke-free as controls. Flukes were counted at slaughter 36 weeks after initial infection. Mean daily weight gains of infected Bali (228 ± 100 (SD) g/day) and infected Ongole calves (328 ± 57 (SD) g/day) were lower (p = 0.026 and 0.067, respectively) than those of control calves (405 ± 107 (SD) g/day), but infected buffalo calves (379 ± 78 (SD) g/day) had similar weight gains to those of the controls (p = 0.57). Throughout the trial, faecal Fasciola egg counts in buffaloes were about one-fifth of counts of Ongole calves, and counts in Bali calves were intermediate. Ongole calves had three times the number of flukes at slaughter in their liver compared to buffalo and Bali calves, which had similar numbers. However, there was evidence that Bali calves had acquired a degree of resistance about 24 weeks after infection commenced and may have lost adult flukes as a consequence.     

The effect of ahemeral light and dark cycles on patterns of food intake by the laying hen

1. Diurnal food intake rhythms of laying hens were studied under 21, 24 and 30‐h cycles, using either a constant 12‐h photoperiod or a 10‐h scotoperiod in each cycle. The feeding patterns essentially followed a circadian periodicity under all experimental situations. The peak in food intake which normally occurs before “sunset” in a 24‐h cycle was consistently observed to be timed from the onset of the previous dark period in each light and dark cycle, regardless of cycle length.

2. This study demonstrates that the laying fowl makes use of an endogenous biological rhythm to regulate its feeding behaviour. A light to dark transition in a light and dark cycle is the primary signal for phase‐setting the pattern of food intake.     

Low-dose ginseng (Panax quinquefolium) modulates the course and magnitude of the antibody response to vaccination against Equid herpesvirus 1 in horses

The purpose of this study was to determine if ginseng fed at low levels enhances a horse's antibody response to vaccination against Equid herpesvirus 1 (EHV-1). For 28 d, 5 horses received ground, powdered ginseng (35 mg/kg body weight, 1.7 mg/kg total ginsenosides) in molasses as a carrier, and 5 received molasses only. On day 14, each horse was vaccinated against EHV-1. The time course of the antibody response to vaccination was significantly altered in the horses receiving ginseng, a clinically relevant increase in antibody titer being observed by postvaccination day 2 compared with day 6 in the control horses. The horses receiving ginseng also had a significant decrease in serum levels of sodium and a significant increase in serum levels of potassium. No adverse effects of ginseng treatment were identified by hematologic and blood biochemistry profiles. Thus, low-dose dietary supplementation with ginseng in healthy horses may be a useful adjunct to vaccination.     

Noise output of hens subjected to interrupted lighting regimens

1. Noise output from domestic hens subjected to an interrupted lighting regimen began before dawn of the apparent day. 2. Noise output did not cease during the scotoperiod(s) which interrupted the apparent day. 3. Differential noise outputs during the 30 min. 4 h and 10 h scotoperiods of a 1L:7(30D:30L):4D:2L:10D regimen indicated that the hen's interpretation of darkness, even within the apparent day, was complex and probably dependent on several factors. 4. Noise output data suggested that the intense feeding behaviour at the end of the apparent day, effected by the interrupted lighting regimen, appeared to prevent the pre-dusk reduction in activity observed in conventionally lighted birds. 5. Noise output was negligible during the scotoperiod which the hen interpreted as night.     

不同温度下雌雄葎草营养生长期的生长特性

通过测定15、20、25 ℃培养条件下,雌雄葎草(Humulus scandens)单株营养生长期持续时间,根、茎、叶等构件数量性状及鲜质量、干质量和生物量分配等指标,分析温度对营养生长期雌雄葎草生长特性的影响。结果表明,温度对葎草营养生长持续期有极显著影响（P＜0.01）,雌株比雄株更易受影响;温度极显著影响根、茎、叶等构件数量性状及其鲜质量与干质量;温度极显著影响营养生长期雌、雄葎草单株的生物量总量及构成,雄株通过减少叶生物量、雌株通过增加根系生物量来为生殖生长提供物质基础。