共查询到20条相似文献，搜索用时 34 毫秒
1.
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. 相似文献
2.
1. The welfare of male and female male-line turkeys fed ad libitum or food-restricted was determined at 4, 8, 12, 16, 20, 24, 28, 36(38) and 46(48) weeks of age using behavioural and physiological indices of well-being. Traditional turkeys fed ad libitum were kept as a control treatment. Restricted male and female male-line turkeys were fed to 0-5 during rearing and subsequently to 0-8 of sex-specific ad libitum-fed body weight. In another treatment, male-line males were fed ad libitum to 18 weeks and 0.8 of ad libitum thereafter. 2. Traditional turkeys and restricted male-line turkeys were more active than ad libitum-fed birds of both sexes. Restricted turkeys showed a high incidence of wall pecking. In the breeding period, about 0.4 of the observations of male-line males were of strutting behaviour whereas traditional male turkeys showed no strutting behaviour at the end of the breeding period. 3. The heterophil lymphocyte ratio (HLR) and the proportion of basophils were not increased in food-restricted turkeys. The HLR was relatively low in traditional birds, compared with male-line turkeys during the rearing period. 4. Plasma corticosterone concentrations were increased by food restriction during the rearing period. Corticosterone concentrations were relatively high in traditional turkeys at 4 and 8 weeks of age only. 5. Plasma lactate dehydrogenase (LIDH) activity was higher from 12 to 24 weeks of age in ad libitum-fed male-line turkeys and was consistent with mortality from cardiovascular disease in this group of turkeys. The pattern of activity of aspartate transaminase was similar, and alkaline phosphatase was inversely related to that of LDH. 6. It was concluded that turkeys may be better able to adjust physiologically to the demands of food restriction than broiler breeders and that there were few deleterious consequences of restricting male turkeys after 18 weeks of age. Male-line turkeys were less active than traditional turkeys. 相似文献
3.
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. 相似文献
4.
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
5.
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. 相似文献
6.
1. Ovarian function was assessed at first egg and at 44 and 54 weeks of age in traditional turkeys and in a male-line fed ad libitum or restricted to 0.5 of ad libitum during rearing. Egg production was recorded daily and fertility and hatchability were determined at 2 ages. 2. Age at sexual maturity did not differ between the 3 treatments. 3. The number of follicles at first egg in the male line averaged 16.3 compared with 8.9 in traditional turkeys. Food restriction in the male line decreased the number of yellow follicles to 14.6 at first egg and restricted birds were largely in a non-reproductive state from 44 to 54 weeks of age. 4. The total number of recorded ovipositions to 54 weeks of age in male line fed ad libitum or restricted and traditional turkeys respectively were 40.1, 25.2 and 70.7; comparable productions of normal shelled eggs were 28, 20 and 66.3. 5. There were no differences between treatments in fertility after a single insemination at 2 different ages. Hatch of fertiles after the first inseminations were 71.4, 45.5 and 90.3 respectively for male line fed ad libitum or restricted and traditional turkeys. 相似文献
7.
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. 相似文献
8.
Production responses of laying hens to food restriction during rearing were measured in two trials. Food was restricted by two methods: time restriction (TR, food continuously available for 24 to 30 h each 72 h) and proportion restriction (PR, daily allocations of about 60 to 70% of that consumed by ad libitum fed birds (F]. The rearing treatments were applied from 42 to 162 d and from 56 to 168 d of age in experiments 1 and 2 respectively. All birds were fed ad libitum in the laying period to 437 d and 476 d of age in experiments 1 and 2 respectively. Body weight was reduced significantly in both experiments by both methods of restriction, but more so by TR. Marked compensatory growth accompanied the high food intake following the end of food restriction. There was a significant increase in average egg weight concommitant with a change in the relationship between egg weight and age. Possibly this is due to an altered pattern of food intake at onset of lay. 相似文献
9.
10.
Effects of ambient temperature and restricted feeding on the growth of feathers in growing turkeys 总被引：2，自引：0，他引：2
1. Male turkeys were reared to 6 weeks of age at 15 degrees C and 26 degrees C and fed ad libitum or restricted to 0.5 of the body weight of birds fed ad libitum. Basal metabolic rate was determined by indirect calorimetry at an ambient temperature of 20 degrees C. 2. Turkeys at 15 degrees C were lighter than those kept at 26 degrees C. Feather lengths and weight were similar in both groups. Fasting heat production corrected for both metabolic body size and activity was greater in turkeys reared at 15 degrees C than those at 26 degrees C. 3. Cranial breast feathers were significantly longer in restricted birds than in those fed ad libitum in contrast to a proportional decrease in the lengths of other feathers of 0.1 to 0.3. Feather weight as a proportion of body weight was 0.072 in restricted turkeys compared with 0.046 in birds fed ad libitum. There was no difference in basal metabolic rate between ad libitum and restricted turkeys. 4. It was concluded that feather growth was maintained in preference to body and muscle growth and that rearing birds at 15 degrees C did not improve breast feather cover. It is suggested that the growth of breast feathers in turkeys fed ad libitum is impaired. 相似文献
11.
1. Females from a medium body weight strain of turkeys were fed ad libitum or restricted to 0.6 of ad libitum-fed body weight at sexual maturity and were photostimulated at 18, 24 or 30 weeks of age. Ovarian follicular structure was assessed in 8 birds from both rearing treatments at photostimulation, after photostimulation for 6 or 12 weeks and at 55 weeks of age. 2. The patterns of small white follicles and of larger yellow follicles were similar in restricted and in ad libitum-fed turkeys for birds in lay at the same age, regardless of the time elapsed since photostimulation. 3. Among birds in lay the number of normal yellow follicles and the proportion of multiple yellow follicles declined with age. A relatively low proportion of restricted birds photostimulated at 18 and 24 weeks were in lay after 12 weeks of photostimulation. 4. For birds in lay the number of white follicles 1.4 to less than 1.8 mm in diameter increased and the number greater than 1.8 mm declined with age. There was a corresponding increase in the rates of atresia in follicles 1.8 to less than 5.0 mm in diameter. 相似文献
12.
1. A total of 4000 Ross broiler breeders were reared to a 20-week target body weight of 1.55, 2.16 (standard), 2.50 or 2.84 kg, using either a convex or concave growth curve. Each treatment group was either exposed to a conventional broiler breeder lighting regimen, with a series of weekly one-hour increments in photoperiod from 8h at 19 weeks to a 16-h maximum, or maintained from 4d on a 17-h photoperiod. 2. Each 100 g increment in body weight at 20 weeks was associated with a significant increase of 0.55 kg in cumulative food intake, and a 1.5-d advance in sexual maturity. However, leaner body weights at 20 weeks resulted in smaller body weight gains between 20 and 60 weeks (-2.4 g/d/kg body weight at 20 weeks), and an increased production of double-yolked eggs. Neither egg production nor mean egg weight was affected by 20-week body weight. 3. Birds fed to produce more rapid early growth had higher feed intakes to 20 weeks, but reached sexual maturity 7 d later than birds permitted accelerated growth from 15 weeks. Growth curve did not influence body weight gain in lay, egg production or mean egg weight. 4. Birds maintained on 17-h photoperiods reached sexual maturity 27 d later, produced 7 fewer eggs to 60 weeks, and had a mean egg weight 1.2 g heavier than birds photostimulated at 19 weeks. Lighting treatment did not affect food intake to 20 weeks, the proportion of double-yolked eggs or body weight gain between 20 and 60 weeks. 5. Birds fed to have a faster growth early in the rearing phase and maintained on 17-h photoperiods produced 11 fewer eggs than those fed to have accelerated growth at the end of the rearing phase, yet there was only one egg difference between the growth-curve groups for the conventionally lighted birds, which was not significant. 6. The earlier sexual maturity of the conventionally lighted birds compared with those maintained on 17-h photoperiods either indicates that broiler breeders require an increment in photoperiod to stimulate rapid gonadal development or that broiler breeders exhibit juvenile photorefractoriness that takes longer to be dissipated when birds are not given a period of short days. 7. The findings suggest that a nutritional stimulus late in rearing is only necessary for satisfactory egg production if birds have not received a concurrent increment in photoperiod. 相似文献
13.
P M Hocking 《British poultry science》1992,33(2):253-269
1. Turkey females were fed ad libitum or restricted from 6 weeks of age to achieve mean body weights of 0.6 of ad libitum fed birds on photostimulation at 18, 24 or 30 weeks of age. Body weight, food intake, egg production and hatchability were recorded to 54 weeks of age. 2. Restricted turkeys were fed ad libitum after first egg or 36 weeks of age. Food intake after 30 weeks of age averaged 170 g/bird/d and was similar for all treatments. At 54 weeks of age, restricted turkeys photostimulated at 24 and 30 weeks were not as heavy as turkeys photostimulated at 18 weeks and ad libitum fed turkeys. 3. A large proportion of restricted turkeys photostimulated at 18 weeks of age did not commence lay until 30 to 40 weeks and a significant number of restricted birds photostimulated at 24 weeks had short laying cycles. Restricted birds photostimulated at 30 weeks came into lay and showed similar persistency of lay to ad libitum fed turkeys. 4. Ad libitum fed turkeys laid 115.0, 122.0 and 101.0 and restricted turkeys 92.4, 99.5 and 103.4 eggs when photostimulated at 18, 24 and 30 weeks, respectively. The number of non-settable eggs was lower in restricted compared with ad libitum fed turkeys and declined with age at photostimulation. 5. Egg size at the end of the experiment was similar for ad libitum fed turkeys and restricted birds photostimulated at 18 weeks but was 2.3 g lower for restricted birds photostimulated at 24 and 30 weeks of age. 6. Hatchability was higher, and the proportion of second quality poults was lower with eggs from restricted turkeys. The mean numbers of poults hatched were 59.9, 75.1 and 66.0 for ad libitum fed and 71.7, 65.7 and 79.4 for restricted turkeys photostimulated at 18, 24 and 30 weeks of age. 相似文献
14.
Effects of food intake regulation on the energy metabolism of hens and cockerels of a layer strain 总被引：1，自引：0，他引：1
1. Indirect calorimetry was used to study the effects on the energy metabolism of cockerels and hens after peak lay of a hybrid layer strain of regulating food or energy intake to 80% of ad libitum for an extended period of time. 2. Regulation of food intake decreased fasting and fed heat productions per bird and per unit metabolic body weight (kg0.75). 3. Maintenance energy requirements (per kg0.75) of both sexes were reduced about 20% by regulation; maintenance requirements of cockerels were about 30% lower per kg0.75 than hens on the same treatments. 4. Reducing the intake of all nutrients by 20% had the same effect on the energy metabolism of cockerels as restricting energy alone by the same amount. 5. Gross efficiency of egg production, in terms of both mass and energy, was higher when intake was regulated. During weeks 21 to 52 of restriction, daily egg mass output was significantly higher in hens fed ad libitum. 6. After 52 weeks of food regulation, restricted hens weighed 20% less and their total carcass energy was 36% less than hens fed ad libitum; similar effects were found in the cockerels. 相似文献
15.
P. M. Hocking 《British poultry science》1996,37(4):841-851
1. The role of body weight during rearing and food allocation after photostimulation on ovarian function in broiler breeder females was examined in two experiments. In experiment 1 birds were fed ad libitum, or to grow to 0.7 or 0.4 of ad libitum‐fed body weight at 20 weeks of age. After photostimulation at 16, 19 and 22 weeks respectively they were fed ad libitum, 145 g/d or 115 g/d in a factorial design. The ovary of each bird was examined after it had laid an egg. In experiment 2, restricted birds (0.4 of ad libitum‐fed body weight) were fed 125 g/d after laying an egg or ad libitum and a third group were given 125 g/d for 3 to 4 weeks and then fed ad libitum. The ovaries of these birds were examined 6 to 7 weeks after their first egg.
2. Food restriction after photostimulation had little effect on ovarian function in birds fed ad libitum during rearing. These birds had 2 to 3 hierarchies of yellow follicles of similar size. Restricted birds fed ad libitum after photostimulation had a large increase in the numbers of yellow follicles (1.7 to 2.0 hierarchies) compared with birds fed 145 g/d or 115 g/d which had 1.2 to 1.6 hierarchies of yellow follicles.
3. Age at first egg was largely a function of rearing treatment but feeding 115 g/d to the 0.4 treatment birds delayed the onset of lay compared with the other treatments.
4. Ad libitum feeding in restricted birds after the onset of lay resulted in a similar increase in the number of yellow follicles as the response to ad libitum feeding after photostimulation.
5. The prevalence of birds with atretic follicles was relatively high in birds fed ad libitum during rearing and in restricted birds fed ad libitum after photostimulation.
6. Yolk weight increased with age at photostimulation and food restriction decreased yolk weight by about 1 g compared with ad libitum feeding after photostimulation. 相似文献
16.
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
17.
P M Hocking 《British poultry science》1991,32(1):211-218
1. The consequences of limiting body weight gain during rearing on subsequent semen production and quality of Large White turkey males were assessed in a factorial experiment comparing ad libitum or restricted feeding in two periods (6 to 18 and 19 to 54 weeks of age). 2. The proportion of males giving semen, semen yields and concentrations of spermatozoa, and the incidence of unstable hock joints, were lower in males severely restricted from 6 to 18 weeks of age. 3. The best performance was from males that were reared on ad libitum feeding and fed 0.85 of ad libitum food consumption from 19 to 54 weeks of age. 相似文献
18.
Heck A Onagbesan O Tona K Metayer S Putterflam J Jego Y Trevidy JJ Decuypere E Williams J Picard M Bruggeman V 《British poultry science》2004,45(5):695-703
(1) Tolerance to ad libitum feeding was compared in three genotypes of broiler breeder hens: a standard broiler breeder fed ad libitum (SA) or restricted (SR), a slow growing 'label' broiler breeder (L) and an experimental dwarf heavy broiler breeder (E). Two similar experiments were conducted in two distinct research centres. (2) Feed intake and body weight were measured every 3 weeks from hatch to 40 to 49 weeks of age. Egg production and egg abnormalities were recorded. The number of yellow follicles in ovaries was counted at the age of 32 weeks. (3) Body weight was stabilised at 2.2, 3.7 and 5.4 kg after 24 weeks of age in L, E and SA hens, respectively. Growth of the SR hens was similar to that of L up to 20 weeks and stabilised at a similar level to that of E hens after 30 weeks of age. (4) Sexual maturity was delayed by 6 weeks in restricted breeders compared to ad libitum fed hens that started to lay at 20 weeks. SA hens had low egg production and a high proportion of defective eggs, which was largely compensated for by feed restriction. However, productivity of SR hens remained lower than that of L breeders. (5) Compared to the low viability and reproductive fitness observed with SA hens, the E dwarf broiler breeder tolerated ad libitum feeding and had better egg production, fewer egg abnormalities and yellow follicles per ovary and a higher egg production. However, laying rate was still lower than that of the SR and L groups. Energy conversion (kJ/g egg) from 32 to 40 weeks of age was much higher in the SA group than in the other three groups. 6. The feasibility of feeding a dwarf broiler breeder ad libitum calls for further research on implications of specific IGF and GH-receptor expression at the level of the ovary in dw chickens. 相似文献
19.
1. White blood cells and thrombocyte values were examined in normal domestic fowls of layer and broiler strains fed restricted or ad libitum diets. 2. Basophils were the only white blood cells to increase significantly in number after the period of food restriction. It is suggested that the increase may have been associated with stress. 3. There were more basophils in broilers than layers, in males than females and in younger than older birds. 4. In contrast, a decrease in the total number of white blood cells was seen in birds maintained on a restricted diet compared with those fed ad libitum. 5. Stress may also have been responsible for an increased thrombocyte count in the restricted birds as well as a slightly lowered eosinophil count. 6. Heterophil/lymphocyte ratios were not significantly altered by the restriction of food. 相似文献
20.
P. M. Hocking 《British poultry science》1988,29(3):531-544
1. Severe restriction of food from 6 to 54 weeks of age resulted in lower body weights and smaller testes weights in male turkeys.
2. As a proportion, mortality was 0.5 in turkeys fed ad libitum and 0.1 in those which were restricted. There were significantly fewer leg problems in the birds undergoing food restriction.
3. Sexual maturity was delayed 4 weeks by food restriction although semen quality was similar to that in ad libitum‐fed birds.
4. Individual semen production was lower after food restriction but, because mortality and food consumption were also lower, semen production per male housed and semen production per kg of food eaten were proportionally 0.30 and 0.32 greater in restricted‐compared with ad libitum‐fed turkeys.
5. Useable quantities of good quality semen were obtained from ad libitum‐fed turkeys at 23 weeks of age.
6. A short photoperiod (7L:17D) from 10 to 18 weeks of age in ad libitum‐fed turkeys produced more rapid development of normal semen production compared with turkeys given a longer photoperiod (14L:10D). 相似文献