不同光周期对肉仔鸡采食行为、生长性能及血液指标的影响

本试验旨在探讨4种光周期对肉仔鸡采食行为、生长性能及血液指标的影响,为提高肉仔鸡的生长性能与福利水平提供理论参考依据。试验选择体况相近、健康的14日龄WOD168肉仔鸡96只,随机分为4个处理,每个处理4个重复,每个重复6只鸡。4个处理的光周期分别为23L∶1D(处理1)、16L∶8D(处理2)、8L∶4D∶8L∶4D(处理3)、8L∶16D(处理4),均采用LED白光灯照明,其他饲养管理条件一致。预试期7 d,正试期3周。结果表明:在整个试验期,处理3的采食时间百分比显著高于处理4(P0.05);处理2的采食频次显著高于处理1(P0.05),但处理1的最小采食时间显著高于处理2、3(P0.05)。在明期,处理2、3、4肉仔鸡的采食时间百分比、采食频次均显著高于处理1(P0.05);处理1的最小采食时间显著高于处理2、4(P0.05)。在暗期,处理4的采食时间百分比、采食频次、最大采食时间显著高于处理1、2、3(P0.05);处理4的最小采食时间显著高于处理1、3(P0.05)。此外,处理4的料重比(F/G)显著低于处理1(P0.05);处理1的血液白细胞数量显著高于处理4(P0.05),总胆固醇含量显著高于处理2(P0.05)。由此可见,为提高采食行为的表达、降低鸡只生理应激,建议在生产中采用8L∶4D∶8L∶4D的光周期。     

肉鸡饲养管理注意事项

1注意自由采食肉仔鸡原则上是让其采食充足,摄入足够的料量。饲喂方法是不断料,自由采食。肉仔鸡夜间必须喂料,28日龄后     

柑桔皮粉+金霉素作肉仔鸡饲料添加剂的试验

选用21日龄的京黄肉仔鸡180只，随机分成3组，2种试验日粮分别添加1．5％柑桔皮粉和1．5％柑桔皮粉＋30ppm金霉素。试期38天，自由采食和饮水。结果，肉仔鸡体增重、饲料利用率均以添加1．5％柑桔皮粉＋30ppm金霉素组最高，分别比对照组提高14．83％、13．52％。     

保加利亚乳杆菌及其代谢产物对肉仔鸡生长性能的影响

将5 00只1日龄的肉仔鸡随机分成5组,1个对照组和4个试验组,每组5个重复,每个重复20只鸡.对照组肉仔鸡采食基础日粮,试验1组肉仔鸡饮水中添加保加利亚乳杆菌代谢产物,试验2组肉仔鸡基础日粮中添加保加利亚乳杆菌活菌体,试验3组肉仔鸡采食基础日粮添加保加利亚乳杆菌菌体及其代谢产物,试验4组肉仔鸡采食某市售微生态制剂,试验期6周.结果表明,相对对照组及其他试验组,日粮中添加保加利亚乳杆菌及其代谢产物能够提高肉仔鸡成活率、体重增长、降低肉仔鸡腹泻率,但对肉仔鸡新城疫免疫效果影响不大.     

报刊集锦

环境温度对 21日龄肉仔鸡 生长与饲料转化率的影响 　　　　生长期间，环境温度是影响肉仔鸡生产效率的主要因素。本研究测定 5种施温措施到 21日龄时，对肉仔鸡生长情况、饲料转化率及死亡率的影响，从而为肉仔鸡的生产选择最优环境提供参考信息。在 10个禽舍中， 5个禽舍养公雏， 5个禽舍养母雏。公、母雏舍的初始温度分别设置为 28℃、 29℃、 30℃、 31℃和 32℃，随后各组温度均每天降低 0.3℃。整个实验期间露点设定为 15.7℃，持续光照，自由采食与饮水。在 7、 14和 21日龄时，分别统计各组的增重、饲料转换，另外对整个期间的死亡…     

富集型笼具对肉仔鸡行为与福利的影响

为探讨富集型笼具对肉仔鸡行为的影响,本研究采用单因子四水平试验设计,选择健康、体重相近的21日龄肉仔鸡128只,随机分为4个组,每组32只,公母各半,1组作对照,笼内不设置富集物体;2、3、4作试验组,分别在笼内设置栖木、垫料与同时设置栖木、垫料等富集物体,观察分析4～6周龄肉仔鸡的各种行为.结果表明:采食频次和时间2、3、4组显著高于1组(P＜0.05);梳羽频次和时间1组显著高于4组(P＜0.05).饮水、趴卧、行走、站立、伸展等行为的发生频次和时间各组间无显著差异(P＞0.05),但趴卧频次和时间1组比2、3、4组有增加的趋势;啄物、争斗等异常行为发生频次和时间1、2组显著高于3、4组(P＜0.05),同时,1组比2组也呈增加的趋势.探究、抖身等舒适行为发生时间4个组分别为1.89％、2.28％、2.53％和5.49％.因此,富集型笼具使肉仔鸡的采食更为频发,使啄物、争斗等异常行为减少,并利于其种属内的抖身、探究等舒适行为的表达,提高了其福利水平.     

乳杆菌培养物对肉鸡肠道菌群及形态的影响

将1 500只从肉仔鸡随机分成5组,每组6个重复,1个对照组和4个试验组,对照组肉仔鸡采食基础日粮.试验1组肉仔鸡采食添加0.2%的高产共轭亚油酸(CLA)乳酸菌日粮,试验2组肉仔鸡采食添加0.3%的高产CLA乳酸菌日粮,试验3组肉仔鸡采食添加含0.5%的高产CLA乳酸菌日粮,试验4组肉仔鸡采食添加0.6%的高产CLA乳酸菌日粮,试验期4周.结果表明,试验组可显著降低肠道中大肠杆菌和厌氧菌数量,增加肠道乳酸杆菌的数量;试验组鸡的小肠肠腺和绒毛长度均长于对照组(P<0.01或P<0.05).     

补饲青绿饲料对不同性别肉仔鸡皮肤色泽的影响

研究了在饲喂全价配合日粮基础上补饲青绿饲料对不同性别肉仔鸡全身不同部位皮肤色泽的影响。各组自由采食玉米-豆粕型基础日粮,分别于第1、15、29天开始补饲青绿饲料,比较分析42日龄时的全身各部位皮肤的色泽(L、a、b值)。结果表明,不同性别肉仔鸡各部位皮肤色泽间存在一定的差异性;补饲青绿饲料对肉仔鸡皮肤色泽的影响效应,以黄度最强和亮度最弱;补饲青绿饲料的时间越早,对肉仔鸡皮肤色泽的影响越明显;补饲青绿饲料对母肉仔鸡皮肤色泽的影响比对公肉仔鸡更显著。     

玉米型饲粮和小麦型饲粮对肉仔鸡生长性能、肉品质、血浆生化指标和脂质代谢的影响

本试验旨在研究玉米型饲粮和小麦型饲粮对肉仔鸡生长性能、肉品质、血浆生化指标和脂质代谢的影响。选取健康的1日龄爱拔益加肉仔鸡公雏180只,随机分成2个组,分别采食玉米型饲粮和小麦型饲粮,每组6个重复,每个重复15只鸡。试验期42 d。结果表明:与玉米型饲粮相比,饲喂小麦型饲粮的肉仔鸡,1)生长前期(1~21日龄)和全期(1~42日龄)平均日增重(ADG)显著增加(P0.05),生长前期死亡率显著降低(P0.05);2)42日龄的腹脂率显著降低(P0.05);3)42日龄胸肌肌肉的红度(a*)45 m in和a*24 h值显著降低(P0.05),亮度(L*)45 m in值增加(P=0.096);4)21和42日龄血浆总胆红素含量显著降低(P0.05);21日龄血浆总蛋白和白蛋白含量显著增加(P0.05),21日龄血浆谷氨酸氨基转移酶活性显著降低(P0.05);42日龄血浆尿酸含量显著增加(P0.05);5)21和42日龄血浆甘油三酯含量显著降低(P0.05);42日龄血浆总胆固醇含量显著降低(P0.05)。由此可见,本试验条件下,与玉米型饲粮相比,小麦型饲粮改善了肉仔鸡的生长性能、脂质代谢和健康状态,降低了腹脂率。     

鸡饲料中氨基酸消化率检测方法的比较

在2个试验中,利用肉仔鸡(7日龄和21日龄)标准回肠氨基酸消化率测定法和"定量饲喂"去盲肠成年公鸡氨基酸真消化率测定法,对数种鸡饲料原料的氨基酸消化率进行比较研究。试验1分别以豆粕、棉籽粕、禽类副产品粉和鱼粉作为试验日粮的唯一蛋白质源,试验2则分别以玉米、小麦、豆粕、禽类副产品粉、羽毛粉和鱼粉为试验日粮唯一的蛋白质源。以硅藻土(celite)为不可消化的标记物,按1.5%的浓度加入试验日粮。试验肉仔鸡在0～7日龄(试验1)和4～7日龄及17～21日龄(试验2)期间自由采食试验日粮,分别于7日龄(试验1、试验2)和21日龄(试验2)对试验鸡实施安乐死,同时收集回肠消化糜样本。另外,选择21周龄单冠白来航成年公鸡作嗉囊插管手术,以进行试验日粮氨基酸真消化率测定。检测结果表明,试验1中用7日龄肉仔鸡测得的日粮氨基酸消化率显著低于用去盲肠成年公鸡测得的结果,试验2中用7日龄和21日龄肉仔鸡测得的试验日粮中大部分必需氨基酸的消化率没有显著差异。但是,用7日龄和21日龄肉仔鸡测得的部分氨基酸消化率显著低于用去盲肠成年公鸡测得的结果。本研究表明,利用肉仔鸡和成年公鸡测得的氨基酸消化率存在着一定的差异,这些差异可能与所用测定鸡的日龄或两种测定法所采用方法上的差异造成的。     

Circadian variation in heat production and respiratory quotient in growing broilers maintained at different food intakes and ambient temperatures.

1. Circadian variations in heat production (HP) rate and respiratory quotient (RQ) were measured in growing broilers maintained at 5 ambient temperatures (14 degrees, 17 degrees, 22 degrees, 27 degrees and 32 degrees C) and at 5 rates of feeding [ad libitum intake and 75%, 50%, 25% and 0% (fasting) of ad libitum intake]. 2. In most cases, the HP rate decreased from 10.30 h just after food was given) until 00.30 h (the 1-h dark period), showed an overshoot just after the 1-h dark period and then changed little. 3. Circadian variation in RQ, except in the fasted group, showed a similar pattern, which consisted of increase, decrease and constant phases. 4. Food intake affected the pattern of circadian variation in RQ, although ambient temperature had little effect. Possible effects of food intake on the pattern of circadian variation in HP rate were discussed.     

Welfare assessment of modified rearing programmes for broiler breeders

1. Female broiler breeders were fed ad libitum or a restricted quantity of food to achieve either a recommended body weight curve or a modified (linear) growth curve that allowed more generous feeding between 6 and 15 weeks of age. The birds were fed a ration containing either a normal or low concentration of crude protein. The welfare of the birds was assessed using a profile of indices of welfare at 6, 12, 18 and 24 weeks of age. 2. The low-protein ration decreased the body weight of birds fed ad libitum and restricted birds were fed substantially more of the low-protein ration to meet target body weights from 3 to 14 weeks of age. 3. The modified restricted rearing programme did not have an effect on indices of welfare. 4. Water intakes and plasma corticosterone concentrations were lower in restricted birds fed the low-protein ration and they spent more time resting, and less time spot-pecking, than birds fed the high-protein ration. 5. Birds fed ad libitum on both rations spent more time resting and less time foraging, drinking and spot-pecking than food restricted birds and were more fearful than restricted birds at 6, 12 and 18 weeks of age. 6. The heterophil:lymphocyte ratio in restricted birds was higher at 6 weeks and lower at 24 weeks compared with birds fed ad libitum. Humoral immunity was lower at 6 weeks of age in birds fed ad libitum and was similar at other ages. Cell-mediated immunity was similar among all treatments. 7. Plasma corticosterone concentrations were higher in restricted birds compared with birds fed ad libitum. Plasma creatine kinase activity was higher in birds fed ad libitum at 6, 12 and 18 weeks of age. Alkaline phosphatase and lactate dehydrogenase activity were higher whereas AST was lower in restricted birds compared with those fed ad libitum. 8. There was no evidence to support the use of low protein rations or linear growth curves to improve welfare in restricted broiler breeder females.     

Effects of ambient temperature on heat increment of feeding and energy retention in growing broilers maintained at different food intakes

Zero-activity heat production (HP), body temperature (Tb) and energy retention were measured in growing broilers maintained at 5 ambient temperatures (Ta) (14 degrees , 17 degrees , 22 degrees , 27 degrees and 32 degrees C) and at 5 feeding rates (ad libitum intake and 75%, 50%, 25% and 0% (fasting) of ad libitum). Zero-activity HP increased with decreasing Ta and increasing food intake. However, at 14 degrees C, zero-activity HP in birds fed ad libitum and 75% did not show further increase, but those in birds fed less than 75% of ad libitum increased rapidly. Results of the regression of zero-activity HP on Ta ranging from 32 degrees to 17 degrees C indicated that the slope was affected little by food intake, but the intercept decreased with decreasing food intake. Tb increased significantly with increasing food intake. There was little variation with Ta but, at and above 27 degrees C, a slightly increased Tb was observed only in birds fed ad libitum. Overall effects of Ta and food intake on HIF (% TME intake) were not found, but HIF tended to increase with decreasing food intake at 14 degrees C. Total energy retention and energy retention as fat decreased with decreasing Ta and food intake, although energy retention as protein decreased only with decreasing food intake. Results obtained here suggest that availability of TME is affected little by Ta ranging from 32 degrees to 17 degrees C and that HIF is utilised, in part, to maintain Tb at any Ta.     

Plasma oestrogen and triglyceride concentrations and reproductive characteristics of broiler chickens after ten generations of selection at seven weeks of age for high or low plasma very low density lipoprotein concentration.

1. Day old female chicks from two lines of broilers, selected for high or low plasma concentrations of very low density lipoproteins, were fed ad libitum or restricted until point of lay. All birds were fed ad libitum after laying an egg, and aspects of growth and reproduction were measured to 40 weeks of age. 2. Compared with lean line birds the growth rate of fat line females fed ad libitum declined from 16 weeks of age. 3. Mortality from apparently stress-related causes in ad libitum fed fat line females increased from 16 weeks of age and was 71% overall, compared with 26% in ad libitum fed lean line females. Mortality in the corresponding restricted birds was 20% and 7%, respectively. 4. Few fat line females fed ad libitum commenced lay and those which were restricted during rearing stopped laying after the initiation of ad libitum feeding. Egg productions in lean line birds fed ad libitum or restricted were similar. 5. Fat line females fed ad libitum had few yellow follicles and a high rate of atresia at first egg and between 37 and 39 weeks, as did restricted fat line birds between 37 and 39 weeks of age after being fed ad libitum. 6. Plasma concentrations of oestradiol-17 beta were 5-fold higher in fat compared with lean line females at 35 weeks of age. There was a similar large difference in concentrations of plasma triglyceride which reached 59 mg/ml in fat line females fed ad libitum.     

Effects of low dietary protein and different allocations of food during rearing and restricted feeding after peak rate of lay on egg production,fertility and hatchability in female broiler breeders

1. A 3x2x2 factorial experiment was conducted with boiler breeder females to determine the effects of body weight gain (three levels) and conventional or lower crude protein concentrations in the rations during rearing, and restricted or ad libitum feeding after the peak rate of lay on egg production, fertility, hatchability, mortality and food consumption. 2. Compared with ad libitum feeding, conventional food restriction resulted in a decrease in average daily food consumption of 0.6 during rearing, 0.2 during early lay and an increase of 0.4 after the peak rate of egg production. Mortality was decreased by more than half. 3. Restricted birds had higher total and settable egg production, fewer defective or damaged eggshells and higher fertility and hatchability than those fed ad libitum. The modified (more generous) rearing programme resulted in lower rates of egg production and higher rates of mortality compared with the conventional food restriction programme. 4. Low-protein rearing rations were associated with higher rates of food intake, higher mortalities and lower rates of egg production than the conventional protein rations. There were no differences in the fertility or hatchability of eggs between birds fed on the two concentrations of dietary crude protein. 5. Ad libitum feeding post-peak was associated with higher rates of mortality to 60 weeks of age. Post-peak feeding had little effect on the rate of lay or egg weight in conventionally restricted birds fed high protein rations or in birds fed ad libitum. Restricted feeding post-peak decreased the rate of lay and egg weight in birds on the modified restriction programme and in conventionally restricted birds fed on the low protein rations. There was no effect of post-peak feeding on fertility or hatchability of eggs. 6. The total numbers of saleable chicks per kg food consumed were 1.83, 1.72 and 0.52 for conventional, modified and ad libitum feeding during rearing; 1.56 and 1.15 for restricted and ad libitum feeding post-peak: there were no differences associated with protein concentrations of rations fed during rearing.     

Interaction of age,strain, sex and food restriction on plasma creatine kinase activity in turkeys

1. Plasma creatine kinase activity was determined at 4, 8, 12, 16, 20, 24, 28, 38 and 48 weeks of age in male and female traditional turkeys fed ad libitum , in male and female turkeys of a sire-line fed ad libitum or restricted to 0.5 during rearing and subsequently to 0.8 of sex-specific ad libitum -fed body weight, and in sire-line males fed ad libitum to 18 weeks and 0.8 of ad libitum body weight thereafter. 2. Plasma creatine kinase activity was low in traditional turkeys and increased rapidly after 12 weeks of age in males and females of the sire-line of turkeys. 3. Food restriction decreased the activity of plasma creatine kinase. 4. There was no difference in plasma creatine kinase activity between the sexes during rearing. After the onset of lay, the activity in plasma from females decreased at 38 weeks of age and rose dramatically in restricted females at 48 weeks when the birds had ceased laying. 5. The changes in plasma creatine kinase activity in females were associated with concomitant changes in ovarian activity as reflected in altered plasma triglyceride concentrations.     

Comparison of behavior, physical condition and performance of laying hens in four molting methods

The objective of the present study was to evaluate the welfare level of hens in four molting methods by comparing their behavior, physical condition and performance. In total, 96 White Leghorn layers (72 weeks of age) were used. The four molting methods consisted of 10 days of feeding and the first 3 days of water withdrawal WFW); 10 day feed withdrawal (WF) followed by ad libitum access to a layer diet from day 11, 28 days of restricted feeding (RF) and 28 days without withdrawing their feed (NW). The RF and NW hens were fed a low energy diet. The WFW and WF hens showed two clear phases of behavior during the 10‐day fasting period. Explorative and stereotyped behavior increased for WFW and WF hens just after their fast. Standing‐resting then increased for WFW and WF hens while lying‐resting decreased. In contrast, RF and NW hens did not show clear behavioral changes during the 28‐day molt period. The weight loss of the NW hens was more gradual compared with the other three methods. No significant differences were seen in any productive trait among the four methods during the postmolt period. In conclusion, the welfare level of RF and NW, especially NW, was higher compared with WFW and WF.     

Welfare assessment of broiler breeders that are food restricted after peak rate of lay

1. Broiler breeder females were reared on one of three growth curves (ad libitum, conventional or modified restriction) and given rations containing a high or low concentration of crude protein. After the peak rate of lay they were fed ad libitum or a decreasing quantity of food in response to declining egg production. The welfare of the birds was assessed by determining the changes in indices of welfare at 36, 48 and 60 weeks of age. 2. Body weight increased rapidly in restricted birds fed ad libitum post-peak and water intake declined. 3. Post-peak food restriction was associated with a decrease in resting and increased drinking and spot-pecking activities. Birds that were food restricted during rearing spent more time foraging and spot-pecking at 36 and 48 but not 60 weeks of age. 4. Immune function increased with age but was not affected by the experimental treatments. The heterophil-lymphocyte ratio in birds fed ad libitum during rearing was numerically lower at 36 and higher at 48 and 60 weeks of age compared with restricted birds. 5. There was no effect of treatment on plasma corticosterone concentration. Creatine kinase activity was high at 60 weeks in treatments that were characterised by poor reproductive status and the activities of other enzymes reflected differences in reproductive status and mortality. 6. There was no long-term welfare or production advantage from feeding low protein rations or more generous feeding during the rearing period compared with conventional food restriction programmes.     

Reproductive performance of dwarf broiler breeders given different allowances of food during the rearing and breeding periods and two lighting patterns

1. Dwarf broiler breeders were either fed ad libitum or restricted to allow growth to mean body weights of 1.4 or 1.8 kg at 20 weeks of age. During the breeding period these birds were fed ad libitum, or food was restricted to different degrees and the birds subjected to two different incremental lighting patterns. 2. Egg production of birds fed ad libitum during the breeding period increased with the degree of food restriction during rearing. 3. Food restriction during the breeding period increased the egg production of birds weighing 1.8 kg at 20 weeks but decreased that of birds weighing only 1.4 kg. 4. Fertility was relatively low and inversely related to body fatness of females. 5. The differences in lighting pattern did not influence performance. 6. For optimum reproductive performance during the rearing period dwarfs should not be restricted so severely as conventional breeders. Best chick production was obtained from birds with a bodyweight of 1.8 kg at 20 weeks of age, which were subjected to a 10% restriction of food during the breeding period.     

Circadian variation in heart rate, blood pressure, body temperature and EEG of immature broiler breeder chickens in restricted-fed and ad libitum-fed states

1. Heart rate, intra-aortic blood pressure, deep body temperature and telencephalic EEG were monitored by radiotelemetry in 6 freely moving immature broiler breeders (three in each of two years), during routine food restriction and then ad libitum feeding, over two 24-h periods in each feeding state.2. Heart rate, blood pressure and body temperature were all higher during ad libitum than restricted feeding, and heart rate and body temperature were higher by day (12 h) than at night (12 h). The decreases in heart rate and body temperature at night were greater during restricted than ad libitum feeding. Blood pressure tended to be higher at night, except in year 2 during restricted feeding. Body temperature and ambient temperature were higher in year 2 than year 1.3. During restricted feeding, marked peaks in heart rate, blood pressure and body temperature in the 15 min after provision of the daily food ration at 09:00 h, when birds were eating, were equivalent to corresponding values seen during ad libitum feeding.4. Relative powers in delta (1 to 4 Hz) and theta (4 to 8 Hz) frequency bands of the EEG power spectrum were higher at night in year 2 only, while power in the alpha (8 to 12 Hz) band was higher at night in both years.5. It is concluded that most of the variation in heart rate, blood pressure and body temperature between feeding states and times of day/night can be accounted for in terms of variation in food intake and energy expenditure. The greater slow wave (delta, theta) EEG activity seen after lights-off in year 2 may reflect non-paradoxical sleep at that time.