首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
The inconsistent beneficial responses to dietary ascorbic acid (AsA) may be due to dietary factors that alter biosynthesis or tissue turnover of AsA. It has been suggested on the basis of altered tissue AsA that dietary fluoride is a determinant of biosynthesis in chickens. Fluoride may enter the food chain of poultry via industrial contamination, feed ingredients and drinking water. The goal of this study was to ascertain whether dietary fluoride at 300 mg/kg influences l-gulonolactone oxidase (GLO) activity in commercial meat-type chickens. The experimental diet was fed from day-old to 3 weeks and responses measured. Growth and feed conversion were not affected by fluoride in the diet. Dietary fluoride neither inhibited nor enhanced GLO activity nor did it increase or decrease AsA concentration in plasma, liver, kidney, adrenal gland and muscle (pectoralis major). Tissue AsA concentration in ascending order was adrenal > liver > kidney > pectoralis major > plasma. The results are consistent with that reported for the rat and calculations based on the results eliminate fluorine contamination for the inconsistent responses of immature chickens to dietary AsA.  相似文献   

2.
The consequences of chronic corticosterone-induced stress (CCIS) on ascorbic acid (AsA) metabolism in chickens, an animal that syntheses the vitamin, are not known. This study was conducted to determine whether CCIS alters AsA synthesis, as measured by l-gulonolactone oxidase (GLO) activity, tissue AsA, lipid peroxides and tissue total antioxidant capacity (TAC). Stress was induced by dietary administration of corticosterone from 2 to 4 weeks of age and measurements were made at 0, 7 and 14 days post-treatment. Ascorbic acid synthesis was not influenced by CCIS but hepatic, cardiac, renal, bursal and duodenal AsA concentrations were significantly decreased and plasma TAC and uric acid concentrations were significantly elevated. Stress caused significant hepatomegaly and hepatic lipidosis but hepatic peroxides were not elevated despite the slight decrease in hepatic TAC. Tissue TAC varied in different organs. It was markedly elevated in the kidney, reduced by 49% in the spleen, and changes were not detected in the heart and duodenum even though AsA concentration was significantly decreased in all tissues. We conclude that CCIS caused a significant reduction in tissue AsA concentration but did not inhibit GLO activity. The change in AsA concentration was associated with increase, decrease or no change in TAC in tissues examined. The findings suggest that CCIS may alter AsA recycling, influx or turnover in different tissues of chickens.  相似文献   

3.
本试验旨在研究饲粮铜添加水平对 １～２８日龄泰和乌骨鸡生产性能和组织黑色素含量的影响。选用 １日龄泰和乌骨鸡 ２７０只,随机分成 ６组,每组设 ３个重复,每个重复 １５只鸡。试验鸡分别饲喂在基础饲粮（铜含量为 ４．７５ｍｇ／ｋｇ）中添加 ０、５、１５、３０、６０、１２５ｍｇ／ｋｇ铜的饲粮,饲养至 ２８日龄。结果表明：饲粮铜不同添加水平对 １～２８日龄泰和乌骨鸡平均日增重、平均日采食量和料重比均无显著影响（Ｐ＞０．０５）,但适量添加可显著或极显著影响其血清、肝脏、肾脏、皮肤及肌肉的黑色素含量、酪氨酸酶活性（Ｐ＜０．０５或 Ｐ＜０．０１）,并呈现出随饲粮铜添加水平的提高先升后降的趋势。当饲粮铜添加水平为 ３０ｍｇ／ｋｇ时,泰和乌骨鸡血清和组织酪氨酸酶活性及黑色素含量达到峰值。由此可知,玉米 －豆粕型基础饲粮中添加铜可提高泰和乌骨鸡组织黑色素含量,其适宜添加水平为 ３０ｍｇ／ｋｇ。  相似文献   

4.
Japanese quail (Coturnix coturnix japonica) were fed on either a conventional diet (low-fibre) or the same diet diluted with 200 g oak sawdust/kg (high-fibre). The lengths of the colo-rectum, small intestine, two caeca combined and empty gizzard weight were measured at 10 and 20 weeks of age. Food intake and rate of passage were measured and an approximate measure of digestibility was also made. 2. There were separate effects of dietary fibre, sex and age on gut size. It was larger in birds fed on high-fibre diet, in females and in older birds. 3. Increased dietary fibre caused increased food intake, but had no obvious effect on the rate of passage. 4. When quail were fed on the low-fibre diet or the same diet diluted with 200 or 400 g cellulose powder/kg gut size at 20 weeks of age was greatest when the most fibrous diet was fed and decreased concomitantly with dietary fibre concentration. 5. It appeared that differences in gut size between dietary treatments were more a reflection of variations in food intake than of fibre per se, and that the effects of sex and age on gut size were probably similarly explained.  相似文献   

5.
Proprietary broiler diets, containing added copper (125 mg/kg) as sulphate, were fed to broilers in 4 trials (32 pens each) over a one year period without a change of litter. Mould counts in the litter of pens containing birds fed the standard diets decreased to 2 X 10(3) propagules per g in trial 4. Those in the pens with birds fed the diets containing supplemental copper decreased to 6 X 10(2) propagules per g. Litter bacterial counts (10(7) organisms/g) were not affected by dietary copper. Litter copper concentrations in pens where the birds were fed supplemented diets increased significantly to more than 600 mg/kg in trial 4. Dietary copper sulphate addition significantly increased broiler weight gains at 7 weeks in trials 3 and 4 (P less than 0.05) and the efficiency of food utilisation was significantly improved in trial 4. The copper content of the chicks' livers remained unchanged. It is suggested that broiler performance may be independent of dietary copper content. Litter copper concentrations and litter microbial alterations may be important factors.  相似文献   

6.
1. Plasma alkaline phosphatase (ALP) activity was determined in 4 laying strains (White Leghorn, New Hampshire, Native Brown and Native Barred) at 48 and 54 weeks of age. Birds were fed 1 of 2 isoenergetic diets with calculated crude protein contents of 152 and 181 g/kg. 2. No significant differences in plasma ALP activity were noted between the strains, although significant differences in laying performance between strains were evident. 3. There was no response in plasma ALP activity to the high dietary protein level in any strain. Depressed plasma ALP activity was associated with increasing age of birds. 4. The results failed to confirm the suggestion that ALP activity is related to egg production of the laying hen.  相似文献   

7.
本试验旨在研究饲粮叶酸(FA)添加水平对山麻鸭产蛋性能、蛋品质、生殖器官及血浆生殖激素指标的影响,以确定产蛋期(18~32周龄)山麻鸭FA的需要量。试验选用16周龄的山麻鸭360只,随机分成6个组,每个组5个重复,每个重复12只,单笼饲养。试验蛋鸭饲喂不添加FA的基础饲粮2周后,分别饲喂在基础饲粮中添加0、0.5、1.0、2.0、4.0、8.0 mg/kg FA的试验饲粮,试验期15周。结果表明:1)饲粮FA添加水平对产蛋初期、产蛋高峰期和试验全期的蛋鸭产蛋性能指标无显著影响(P0.05)。2)随着饲粮FA添加水平的提高,蛋壳相对重和蛋壳厚度先升高后下降,1.0 mg/kg FA添加组的蛋壳相对重显著高于其他组(P0.05)。3)随着饲粮FA添加水平的提高,优势卵泡重、优势卵泡重/卵巢重先升高后降低,饲粮FA添加水平对优势卵泡重和优势卵泡重/卵巢重有显著影响(P0.05),以4.0mg/kg FA添加组最高。4)随着饲粮FA添加水平的提高,血浆孕酮浓度先升高后下降,其中2.0 mg/kg FA添加组血浆孕酮浓度最高;8.0 mg/kg FA添加组血浆促黄体生成素浓度显著高于其他各组(P0.05)。由此可见,在玉米-豆粕型饲粮中添加FA在一定程度上有利于促进优势卵泡的发育,但未能显著影响山麻鸭的产蛋性能。仅考虑产蛋性能,玉米-豆粕型饲粮中不需添加FA;以蛋壳相对重和蛋壳厚度为评价指标,建议玉米-豆粕型饲粮FA适宜添加水平为1.0 mg/kg。  相似文献   

8.
A complete two by two by four factorial design was used to examine the main effects of dietary fat type (10% soya oil or 10% beef tallow), xylanase supplementation (with or without Avizyme 1300 at 1 g/kg diet) and pentosan level (7.7 g/kg, 11.0 g/kg, 14.3 g/kg and 17.6 g/kg soluble pentosans, respectively, by varying wheat/rye proportions) as well as their interactions on intestinal chyme conditions, nutrient digestibility and nutrient utilization in male broilers. Nutrient digestibilities for the total digestive tract and at various sites of small intestine were measured during the period from day 18 to 20 of age and at day 21 of age, respectively, using a marker technique. Jejunal and ileal supernatant viscosity increased in an exponential manner as dietary pentosan concentration was increased. This increase was more pronounced in tallow fed birds but was also found in enzyme treated groups albeit at a much lower level. Xylanase activity was still detectable in the ileum of birds fed enzyme supplemented diets but its activity was found to decrease as dietary pentosan content increased. Digestibility of crude protein and that of some amino acids at the terminal ileum was decreased as dietary pentosan content was increased and significantly improved by xylanase addition. No fat effect and no interactions were detected at this site. In contrast, measurements made over the whole gastrointestinal tract showed significantly lower protein and amino acid digestibility values for tallow fed birds, and significant higher enzyme effects especially in diets with higher pentosan concentrations. Nitrogen-corrected apparent metabolizable energy (AMEN) content and net protein utilization decreased with increasing dietary pentosan content and were significantly improved by xylanase addition and were lower in tallow fed birds. Again, xylanase effects were found to be more pronounced for tallow fed birds and at higher pentosan concentrations.  相似文献   

9.
1. One-day-old Taiwan Native Breeder female chicks were fed on maize/soybean growing diets without supplemental vitamin E from hatch to 17 weeks of age. After 17 weeks the birds (n = 300) were randomly assigned to 5 dietary treatments and fed on maize/soybean laying diets supplemented with 0, 40, 80, 120 and 160 mg/kg of vitamin E (dl-alpha-tocopherol acetate), respectively, until 46 weeks of age. The variates measured included: age at first egg, feed consumption (FC), feed efficiency (FE), egg production (EP), egg weight (EW), egg specific gravity (ESG), eggshell strength (ESS), fertility and hatchability. 2. The addition of 120mg/kg of vitamin E lowered the first EW (P<0.05); however, there was no significant difference in the age or body weight (BW) of pullets at first egg or mortality rate to 46 weeks of age among the treatments. FE and egg mass were improved (P<0.05) in pullets fed 80 mg/kg of supplemental vitamin E. A significant increase in EP was observed after peak EP in pullets given 80 mg/kg of supplemental vitamin E. However, this favourable effect decreased as supplemental vitamin E exceeded 80 mg/kg. 3. From 17 to 46 weeks of age, egg quality (ESG and ESS) decreased with age. However, there was no correlation between age and fertility or hatchability during the experimental period, suggesting that egg quality is more age-sensitive than reproductive performance for breeder pullets. 4. Compared with the control, fertility and hatchability of all eggs set for the treatment with 80 mg/kg supplemental vitamin E increased by 7.7 and 13.4%, respectively. There was no difference in the hatchability of fertile eggs. 5. These results suggest that using supplemental vitamin E during the laying period can improve the reproductive performance of breeder pullets. The addition of 80 mg/kg of vitamin E obtained the best performance in EP, egg mass, FE (feed/egg), hatchability and fertility.  相似文献   

10.
Lu L  Luo XG  Ji C  Liu B  Yu SX 《Journal of animal science》2007,85(3):812-822
An experiment was conducted using a total of 336 one-day-old, Arbor Acres commercial male broilers to investigate the effect of dietary Mn supplementation on carcass traits, meat quality, lipid oxidation, relative enzyme activities in abdominal fat and meat, and Mn-containing superoxide dismutase (MnSOD) mRNA level in meat. Broilers were randomly allotted by BW to 1 of 8 replicate cages (6 chicks per cage) for each of 7 treatments in a completely randomized design involving a 2 x 3 factorial + 1 arrangement of treatments. Dietary treatments included the corn-soybean meal-based diet (control) and the basal diet supplemented with 100 or 200 mg of Mn/kg as MnSO(4) x H(2)O, Mn AA A with a chelation strength of 26.3 formation quotient (8.34% Mn), or Mn AA B with a chelation strength of 45.3 formation quotient (6.48% Mn). Birds fed supplemental Mn had lower (P < 0.10) percentages of abdominal fat, lipoprotein lipase (LPL), and malate dehydrogenase activities and greater (P < 0.07) hormone-sensitive lipase activities in abdominal fat than birds fed a control diet. Birds fed supplemental Mn from Mn AA A or Mn AA B had lower (P < 0.05) LPL activities in abdominal fat than those fed supplemental MnSO(4) x H(2)O. Birds fed supplemental Mn had lower (P < 0.03) malondialdehyde content in leg muscle and greater (P < 0.02) MnSOD activities and MnSOD mRNA level in breast or leg muscle than those fed the control diet. Birds fed supplemental Mn from Mn AA A had a greater (P < 0.02) MnSOD mRNA level in leg muscle than those fed supplemental MnSO(4) x H(2)O. Results from this study indicated that organic Mn was more available than inorganic Mn for decreasing LPL activity in abdominal fat of broilers, and dietary Mn might reduce abdominal adipose deposition by decreasing LPL and malate dehydrogenase activities or increasing hormone-sensitive lipase activity in abdominal adipose tissue. The results also indicated that dietary Mn upregulated muscle MnSOD gene expression pretranslationally in association with increased MnSOD activity, which might explain the decrease of malondialdehyde content in leg muscle.  相似文献   

11.
1. The response of the reproductive system to photostimulation was investigated during the rearing period in dwarf broiler breeder females maintained from hatch on 8 h light/d. The effect of increased body fat on this response was investigated. Body fat was increased by diluting the diet with maize oil. 2. A significant increase in plasma luteinising hormone (LH) was observed 4 d after photostimulation with 20 h light/d at 3 and 15 weeks of age in birds fed the restricted diet alone and at 3, 7, 11, 15 and 19 weeks of age in birds fed the restricted diet diluted with maize oil. 3. Increases in ovarian weight were observed two weeks after photostimulation at 15 weeks of age in birds fed the restricted diet alone and at 7, 11 and 15 weeks of age in birds fed the restricted diet diluted with maize oil. Increases in oviduct weight were seen after photostimulation at 11, 15 and 19 weeks of age in both dietary treatment groups; however, a larger increase in oviduct weight was seen at 15 and 19 weeks of age in birds fed the restricted diet diluted with maize oil. 4. In a second experiment, the dilution of a diet fed ad libitum with maize oil significantly increased body fat content and the baseline concentration of LH but did not enhance the response of the reproductive system to photostimulation. 5. Baseline plasma LH concentrations were lower in birds fed ad libitum than in those fed a restricted diet. 6. It is concluded that the neuroendocrine pathways involved in the transmission of photoperiodic information are functional at 3 weeks of age. The function of the components of the hypothalamo-pituitary complex which control reproductive activity is enhanced when a restricted diet diluted with maize oil is fed.  相似文献   

12.
Background: Laying hens over 75 weeks of age commonly show great declines in immunity and production performance.It is unclear whether these declines can be relieved by supplementing with ascorbic acid(AA) in feed.Two trials were conducted to investigate the synthesis and metabolism of AA in layers of different ages and the effects of dietary supplemental AA on the performance and the immune and antioxidant statuses of 78 weeks old hens.Methods: In Exp.1,equal numbers(24 hens) of 35 weeks old(Young) and 75 weeks old(Old) layers were fed the same diet without AA supplementation for 4 weeks.In Exp.2,360 healthy 78 weeks old laying hens were randomly assigned to 4 treatments(basal diet supplemented with 0,0.25,0.5,or 1 g AA/kg diet) in an 8-week feeding trial.Results: The old hens tended to have decreased L-gulonolactone oxidase(GLO) synthase activity in the kidney and liver than that of the young hens(P = 0.07 and P = 0.05,respectively).Compared with the young hens,the old hens had lower hepatic antioxidant capacity allowing for the lower thioredoxin(TXN),thioredoxin reductase(TXNR) and cytochrome b5 reductase(CYB5 R) gene expression(P 0.05),whereas increased sodium-dependent vitamin C transporter(SVCT) 1 expression levels in the ileum and kidney and enhanced splenic and hepatic AA concentrations(P 0.05).Dietary supplementation with AA significantly decreased GLO enzyme activity but increased splenic AA concentration and anti-bovine serum albumin IgG levels(P 0.05) and tended to increase CD4+T lymphocyte numbers(P = 0.06) in serum.Supplementation of 0.25 g AA/kg diet significantly increased hepatic total antioxidant capacity(T-AOC,P 0.05) relative to the control group.Conclusions: Laying hens could synthesize AA in both the kidney and the liver,though the GLO enzyme activities were 100 times greater in kidneys than in livers.The old laying hens had greater absorption and reabsorption capacity and higher AA retention in some tissues that did the young hens.Dietary supplementation of AA can improve the health of old layers by enhancing immunity and antioxidant capacity.  相似文献   

13.
1. The effects of different dietary concentrations of vitamin E (alpha-tocopherol acetate) were investigated on laying hens exposed to chronic heat stress at 32 degrees C from 26 to 30 weeks of age. 2. Diets containing 5 dietary concentrations of vitamin E (a control diet containing 10 mg alpha-tocopherol/kg or this diet supplemented to contain 125, 250, 375 and 500 mg alpha-tocopherol/kg) were fed to 335 birds. Half of the birds received the supplemented diets for only 4 weeks before the heat stress period (short supplementation duration, SSD) and were fed on the control diet for a further 12 weeks. The remaining birds were fed on the supplemented diets throughout the experiment, 4 weeks before, 4 weeks during and 8 weeks after the heat stress period (long supplementation duration, LSD). 3. Egg production was significantly higher during (80-6 vs 68.9%, P<0.02) and after (75.3 vs 62.7%, P<0.02) the period of stress in the LSD group fed on the diet containing 250 mg vitamin E/kg compared with the group fed on the control diet. LSD birds given 375 and 500 mg vitamin E/kg also had higher egg production than control birds during heat stress but the differences failed to reach significance (74.6 vs 68.9% and 77.1 vs 68.9% respectively). In the SSD groups, mean egg production of the birds given the diets supplemented with 125 mg vitamin E/kg or more was significantly different from the control group after heat stress (70.3 vs 62.7%, P<0.05). Egg weight and food intake were similar in all the groups. 4. Plasma and liver vitamin E concentrations were proportional to the vitamin E intake before the stress period, dropped during heat stress in the SSD groups but were maintained at concentrations closer to those observed before heat stress in the LSD groups. 5. It is concluded that a dietary supplement of 250 mg vitamin E/kg provided before, during and after heat stress is optimum for alleviating, at least in part, the adverse effects of chronic heat stress in laying hens.  相似文献   

14.
本试验采用单因子试验设计,将144羽1日龄健康、体重均一的低脂系肉仔鸡随机分为两组,每组6个重复,每个重复12羽。对照组饲喂基础日粮,试验组饲喂添加0.125%五味子提取物组的基础日粮,试验期为8周,研究五味子提取物对低脂系肉仔鸡肉质的影响。结果表明:(1)与对照组相比,五味子提取物组肉仔鸡胸肌纤维密度显著提高,腿肌直径显著降低(P0.05),腿肌纤维密度有升高趋势,胸肌直径有降低趋势;(2)与对照组相比,五味子提取物组胸肌和腿肌的水分、蛋白质与脂肪含量无显著差异(P0.05);(3)五味子提取物显著降低了肉仔鸡胸肌和腿肌剪切力(P0.05),胸肌和腿肌pH、红度(a*)、黄度(b*)有升高趋势(P0.05),滴水损失和蒸煮损失有降低趋势(P0.05)。  相似文献   

15.
A feeding experiment was conducted to evaluate the effects of dietary sesame meal (SM) on growth performance and histological intestinal alterations of layer chickens. Thirty-two White Leghorn male chickens were divided into 4 groups of 8 birds. They were fed 0, 10, 20, or 30% dietary SM for 28 d. After the feeding experiment, average villus height, epithelial cell area, and crypt cell mitosis numbers were morphometrically compared with an image analyzer, and the results were analyzed with Duncan's multiple range test. The morphological changes of epithelial cells on the villus apical surface were observed morphologically using scanning electron microscope. The growth performance data revealed no significant differences in birds fed up to 20% dietary SM, significantly lower values were revealed in the 30% dietary SM group. At 10% dietary SM, growth performance tended to be improved. Most values of the intestinal villus height, epithelial cell area, and crypt cell mitosis numbers were not different among groups for each intestinal segment. Flat epithelial cells were on the intestinal villus apical surface in the group fed 0% dietary SM. Those cells developed into protuberated cells in the group fed 10% dietary SM, and these protuberated cells disappeared gradually with increasing dietary SM levels. Considerations for current growth performance and histological intestinal alterations suggest that the SM would have no detrimental effect on the growth performance with up to 20% dietary SM nor on the intestinal villi with up to 30% dietary SM, but hypertrophy was observed in the epithelial cells of bird fed up to 20% dietary SM. In conclusion, up to 20% SM could be incorporated into diets fed under commercial conditions to male birds of laying strains in the developer period.  相似文献   

16.
An experiment was conducted with White Leghorn pullets to study the effect on laying performance of dietary protein content and amino acid supplementation during the growing period. From 0 to 6 weeks of age birds fed on diets containing either 149 g protein/kg supplemented with methionine and lysine or 182 g protein/kg grew faster than those fed on a diet containing 149 g protein/kg alone. However, only those fed on the supplemented diet utilised their food more efficiently. From 7 to 20 weeks of age neither body weight gain nor food utilisation was affected by the dietary protein content. Pullets fed the low protein diet supplemented with 2 g methionine/kg and 2.5 g lysine/kg during the period of 0 to 6 weeks of age had significantly better egg production than birds fed the low protein diet alone. The dietary protein content during 7 to 20 weeks of age did not influence subsequent egg production.  相似文献   

17.
1. The relationships between the numbers of ovarian yellow follicles and body weight was investigated in four strains of turkeys photostimulated at 24 or 30 weeks of age. The birds were fed ad libitum or control fed to reach 0.8 or 0.6 of the body weight of ad libitum-fed birds at 24 weeks of age. 2. There were more yellow follicles at 24 compared with 30 weeks of age. 3. The number of yellow follicles was higher in bigger strains. 4. Body weight control reduced the number and the proportion of similar sized yellow follicles. The effect decreased with increasing strain body weight. 5. There was a linear relationship of 0.633 between log yellow follicle number and log body weight. The intercept was higher in turkeys photostimulated at 24 compared with 30 weeks of age.  相似文献   

18.
C Riddell 《Avian diseases》1975,19(3):443-462
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.  相似文献   

19.
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.  相似文献   

20.
1. An experiment was performed to compare the welfare of three broiler breeder genotypes (Label Rouge (LA), experimental dwarf (ER) and standard (SR)) fed on a Control or high Fibre diet. The LA birds were fed ad libitum and the other groups were reared to their recommended body weight targets. A group of standard broiler breeders was also fed a restricted amount of food, but to a lesser degree than SR, to achieve the same proportion of body weight (SE) as ER relative to ad libitum-fed dwarfs based on previous research. LA, ER, SR and SE are referred to as 'groups' in the text. 2. Welfare was assessed by comparing time budgets and heterophil-lymphocyte ratios (HL ratios) at 5, 10 and 15 weeks and immune responses at 15 weeks of age. In addition the weight and water content of the gastrointestinal tract at 4-h intervals at the end of the experiment were studied in LA and SR fed on both diets. 3. Body weights of LA, ER and SR fed on the Fibre diets were depressed and LA ate less of the Fibre than the Control diet. The coefficient of variation of body weight at 15 weeks was 7.9% in LA and similar (10.8 to 11.6%) in the other groups. 4. Drinking, litter-directed behaviour, resting and standing were affected by a group x age interaction with restricted birds showing increased drinking over time and less time spent resting compared to LA. The behaviour of ER birds was similar to SE. 5. HL ratios were within the normal biological range although all restricted-fed birds had an elevated HL ratio at 10 weeks of age relative to week 5 whereas LA birds had a reduced HL ratio at 15 weeks relative to 5 and 10 weeks of age. Immune responses were lower in ER and SE and the highest response was in SR. 6. No effects of diet were identified on behaviour, white blood cell counts or HL ratio. 7. With the exception of the crop, the dry weights of digesta in each section of the gut were similar in LA and SR birds. The results suggest that drinker-directed activity might be a substitute for foraging rather than an attempt to increase gut fill. 8. It is concluded that the replacement of standard with dwarf broiler breeders may improve the welfare of commercial flocks of broiler breeders by decreasing the degree of food restriction resulting in favourable changes in behaviour, for example, reduced 'drinker-directed' behaviour.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号