肉鸡胫骨软骨发育不良研究进展

胫骨软骨发育不良(tibial dyschondroplasia,TD)是发生在多种禽类的一种发展迅速的疾病,而以快速生长的肉鸡最为普遍,给肉鸡生产带来严重的经济损失。该病以胫跗骨或跗趾骨近端生长板出现无血管的白色软骨楔为特征。本文结合国内外的最新研究成果,从临床症状、病因、病理变化、防治等方面对该病进行了综述。     

The development of tibial dyschondroplasia in broiler chickens.

Two strains of broiler chickens selected for a high and a low incidence of tibial dyschondroplasia were fed a standard broiler starter ration with and without added chloride. Development of tibial dyschondroplasia was studied by radiography and serial necropsies. Lesions of tibial dyschondroplasia were mild in the low-incidence strain, regardless of ratio. The defect was more severe in the high-incidence strain and most severe in those birds fed the high-chloride ration. An abnormal thickening of the growth plate was apparent in the high-incidence strain as early as 2 weeks of age and became progressively more severe with age. No significant differences were noted in serum calcium, phosphorus, alkaline phosphatase, pCO2, or bone ash between strains of birds or between birds of the same strain fed different rations. Birds fed the high-chloride ration had a higher serum chloride and a lower serum bicarbonate and blood pH than birds on the standard ration.     

肉鸡胫骨软骨发育不良分子机理的研究进展

对参与肉鸡胫骨软骨发育不良的酶、生长因子、维生素D及其受体，基因表达水平进行了综述，它们形成一个复杂的网络调控系统。阐述了它们在肉鸡胫骨软骨发育不良中所起的作用和变化。认为对参与干扰软骨细胞分化的各种基因的深入研究将为基因选择、消除机能紊乱、防治胫骨软骨发育不良的发生开辟新的途径。     

Footpad dermatitis in broiler chickens in Japan

The prevalence of footpad dermatitis (FPD) in broiler chickens in Japan was investigated. In the first examination at slaughterhouses, lesions were commonly observed on the footpads of a total of 8,985 broiler chickens from 45 flocks on 36 farms. In 3 flocks, all the birds examined had lesions. In the other 42 flocks, the incidence of FPD ranged from 31.9% (81/254) to 99.5% (1/222). The footpad lesions were classified into 4 categories according to the severity of dermatitis as follows; score 0, 1,181 birds (13.1%); score 1, 2,992 birds (33.3%); score 2, 3,000 birds (33.4%); and score 3, 1,812 birds (20.2%). The mean scores of the flocks varied widely from 0.31 to 2.69. Males had higher mean scores than females. No significant differences were found between the mean scores of birds reared in windowless houses and those in open-sided houses. On 4 farms, the investigation was carried out in different seasons, and 3 of them showed higher mean scores in winter than in summer. Next, observation of 2,255 birds from 15 flocks on 5 farms during a 4-week rearing period revealed that FPD was already produced at 7 days of age and worsened with age.     

The influence of dietary calcium and phosphorus on tibial dyschondroplasia in broiler chickens

The incidence and severity of tibial dyschondroplasia in broiler chickens were increased by feeding rations containing high levels of phosphorus relative to the level of calcium. Tibial dyschondroplasia was not eliminated by feeding a ration containing 1.5% calcium and 0.5% available phosphorus. Before typical dyschondroplasia developed, chickens fed a high level of phosphorus had uniformly thickened growth plates at 2 weeks of age. The majority of this thickening was due to an increase in the zone of proliferation, identical to that which occurs in calcium-deficiency rickets.     

Effect of casein phosphopeptide and 25-hydroxycholecalciferol on tibial dyschondroplasia in growing broiler chickens

1. An experiment was conducted to investigate the influence of dietary casein phosphopeptides and 25-hydroxycholecalciferol on the incidence of tibial dyschondroplasia (TD) in 14-d-old commercial broiler chickens. 2. Three hundred and twenty broiler chicks (one day old) were randomly allocated to one of 4 dietary treatments. A standard broiler diet was used as the control with the three experimental treatments receiving the control diet supplemented with 10 g casein phosphopeptide/kg, 14 g casein phosphopeptide/kg or 69 microg 25-hydroxycholecalciferol/kg. 3. Those birds fed the diets supplemented with 14g casein phosphopeptide/kg or 25-hydroxycholecalciferol had a lower incidence of TD than both the control and 10g casein phosphopeptide/kg treatments when assessed grossly. 4. The body weight of birds fed the 10 g casein phosphopeptide/kg diet or the 25-hydroxycholecalciferol diet was higher than birds fed the control diet. Although not significant, the body weight of birds fed the 14 g casein phosphopeptide/kg diet was also greater than the control birds. 5. The current experiment demonstrated that both casein phosphopeptide and 25-hydroxycholecalciferol can reduce the incidence of TD in the young broiler chicken. More research is required to explain the unexpected increase in body weight described above.     

Effect of dietary selenium on the development of Fusarium-induced tibial dyschondroplasia in broiler chickens

A trial was conducted to determine the effects of dietary level of selenium on the pathogenesis of Fusarium-induced tibial dyschondroplasia (FITD) in broiler chicks, and to assess the applicability of FITD as an animal model of Kashin-Beck disease of humans. Day-old female broilers were fed diets that were deficient in selenium (0.02 ppm Se), adequate in selenium (0.15 ppm Se), or generous in selenium (0.50 ppm Se). TDP-1, the toxic component of the fungus, was administered to 15 of 26 chicks in each dietary group starting at 1 week of age and continuing until the chicks were killed at 24-30 days of age. Plasma selenium levels and hepatic glutathione peroxidase activity were significantly lower in the selenium-deficient group than in other dietary groups; these parameters were not affected by treatment with TDP-1. The mortality rate of the TDP-1-treated selenium-generous group was significantly less than that in the other TDP-1-treated groups, but there were no differences in the incidence, severity, or character of the FITD lesions among the groups. Thus, the interaction of selenium and TDP-1 did not include an effect on FITD.     

Outbreaks of adenoviral gizzard erosion in slaughtered broiler chickens in Japan

Gizzard erosion in broiler chickens was investigated at 18 slaughterhouses in Japan. The condition was observed in 13 of them, and adenoviral gizzard erosion (AGE) was diagnosed histologically, immunohistochemically and virologically in the eroded gizzards from nine of these 13. The antigen-positive intranuclear inclusion body of group 1 fowl adenovirus was observed in the epithelial cells of the affected gizzards, and fowl adenoviruses were isolated from the lesions. In two of the slaughterhouses the total weights of the gizzards disposed of in three years were 3590 kg (0.40 per cent of the gizzards inspected) and 2880 kg (0.19 per cent). Sixteen of the 19 outbreaks of gizzard erosion on 15 farms that were confirmed in three of the slaughterhouses, including the previous two slaughterhouses, were diagnosed as AGE, and the condition was suspected in the other three outbreaks. Most of the adenoviruses isolated were identified as serotype-1 by PCR-restriction fragment length polymorphism. No apparent clinical signs were observed in any of the affected flocks.     

Morphogenesis of Fusarium sp-induced tibial dyschondroplasia in chickens

Tibial dyschondroplasia was induced in female broiler chicks by the incorporation of 2% Fusarium roseum "Alaska" culture into their starter ration. Chicks were placed on this diet at one day of age and maintained until they were killed at four days or one week. Proximal tibial physes were grossly thickened into cone-shaped masses of cartilage by one week of age. Microscopically, lesions were in both ages of treated chickens and were characterized by thickening of the transitional zone which was especially prominent in the center of the growth plate. This zone was unmineralized, avascular, and contained chondrocytes which were crenated and densely eosinophilic. The cartilage matrix was pale and contained some patchy eosinophilic foci. Four growth plates with tibial dyschondroplasia and four normal growth plates from each of the four-day and one-week-old age groups were evaluated based on the following parameters: number of metaphyseal vascular sprouts, distance between the proliferative/transitional junction and the tip of the metaphyseal vascular sprouts, width of the tips of the metaphyseal sprouts, distance between tips of adjacent metaphyseal vascular sprouts, and number of perforating vessels in the proliferative zone. The distance between the proliferative/transitional junction and the metaphyseal sprout tips was greatly increased (p less than 0.01) in the affected four-day and one-week-old chickens compared to age-matched controls.(ABSTRACT TRUNCATED AT 250 WORDS)     

Estimation of nutrient excretion factors of broiler and layer chickens in Japan

We estimated the nitrogen (N), phosphorus (P), potassium (K) and magnesium (Mg) excretion factors of broiler and layer chickens in Japan, using two approaches and the latest data available. In the top‐down approach, we determined the nutrient amounts in the feeds and those in the products (i.e. the liveweight gain, eggs), and the national nutrient excretions were determined as the difference between these amounts. We then calculated the nutrient excretion factors by dividing the national excretions by the number of animals. In the bottom‐up approach, we calculated the amounts of nutrients in the feed and product per head using productivity parameters (feed conversion ratio, etc.). The differences between these amounts were considered the nutrient excretion factors. The average nutrient excretion factors of broilers (g/day/head) estimated using the top‐down and bottom‐up approaches were: N, 1.40 and 1.87; P, 0.36, 0.50; K, 0.54, 0.77; Mg, 0.13, 0.18, respectively. The excretion factors obtained by the top‐down approach can be used to calculate the national/regional excretions. The two approaches resulted in almost the same excretion factors for layers, and the average nutrient excretion factors of layers (g/day/head) estimated were: N, 2.20; P, 0.55; K, 0.68; Mg, 0.23. The estimated excretion factors for N (only) are smaller than the reported factors.     

Characterization of a lentogenic Newcastle disease virus isolated from broiler chickens in Japan

Newcastle disease virus (NDV), named MET95, was isolated from a non-vaccinated broiler flock in Japan in 1995. The MET95 strain was determined to be a lentogenic NDV. The strain has the properties of eluting rapidly at 4 C and has low thermostability in hemagglutinating activity with chicken erythrocytes. In these studies, no difference could be found between the MET95 strain and the Hitcher B1 vaccine strain. However, the chickens inoculated with the MET95 strain, as well as chickens that they were in contact with, had a much higher hemagglutination-inhibition antibody response than those inoculated with the B1 strain. Accordingly, the MET95 strain is thought to be a promising candidate as a live ND vaccine strain. In Japan, this is the first report on the isolation of lentogenic NDV from chickens since the paper on the Ishii strain isolated in 1966.     

Swollen-head syndrome in broiler chickens

Swollen-head syndrome is a disease seen in broiler chickens between 4 and 6 weeks of age in Southern Africa. It appears to be caused by a mixed coronavirus and Escherichia coli infection. The coronavirus appears to be of a hitherto unrecorded serotype. The disease is controlled by an attenuated live-virus vaccine and antibacterial medication.     

Salt poisoning in broiler chickens

The clinical signs of salt poisoning in young chickens are thirst, diarrhoea and weakness. When 13 500 broilers are simultaneously affected, the deterioration that occurs in their physical condition and in the litter beneath their feet is dramatic. Two flocks of meat chickens on a small unit in North Otago were affected in this way.     

Campylobacter succession in broiler chickens

The competitive ability of Campylobacter coli OR12 over C. jejuni OR1 has been examined in experimental broiler chickens following the observation that C. coli replaced an established C. jejuni intestinal colonisation within commercial chicken flocks reared outdoors [El-Shibiny, A., Connerton, P.L., Connerton, I.F., 2005. Enumeration and diversity of campylobacters and bacteriophages isolated during the rearing cycles of free-range and organic chickens. Appl. Environ. Microbiol. 71, 1259-1266]. Co-cultures of C. coli OR12 with C. jejuni OR1, revealed that the two species were able to grow together at similar growth rates in exponential growth phase but if the disparity of the inoculum ratios were >log(10)4 in favour of C. coli OR12, C. jejuni OR1 was observed to prematurely enter decline phase. Chickens were pre-colonised with C. jejuni OR1 at 21-days-old to examine succession in vivo. The birds were inoculated between 2 and 12 days later with C. coli OR12, to determine if the second isolate could efficiently colonise and compete with an established C. jejuni strain. C. coli OR12 were able to co-colonise before replacing C. jejuni OR1 as the dominant species when the birds were more than 27 days of age at the time of administration over a 4-day period. If these criteria were met C. coli OR12 became the dominant isolate otherwise co-colonisation occurred until they were met. C. coli OR12 was also found to displace three alternative C. jejuni strains from pre-colonised chickens challenged with C. coli OR12 at 30 days of age and tested at 40 days. These data raise the possibility of manipulating populations of Campylobacter colonising chickens through competition.