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1.
1. Male ducklings were fed for 14, 21 or 28 d on diets containing 180, 200, 220 or 240 g of protein and 10.88 or 12.55 MJ of metabolisable energy (ME) per kg, followed by a common finisher diet until 56 d of age.

2. Birds given starter diets with 220 or 240 g of protein per kg were significantly heavier at 14 d than those given diets with 180 or 200 g protein per kg.

3. There was no significant benefit in feeding diets with protein levels greater than 180 g/kg for more than 14 d.

4. Diets with only 10.88 MJ of ME per kg produced significantly lighter birds at 28 and 56 d of age and significantly reduced food conversion efficiency up to 14 d.  相似文献   


2.
1. The effect of three metabolisable energy (ME) concentrations 12.2, 11.3 and 10.5 MJ ME/kg and two forms of diet (mash and pellet) on egg production in summer and winter were studied. The different ME values were obtained by diluting the 12.2 MJ ME/kg diet with sugar beet pulp of 2.88 MJ/kg DM. In a 3rd summer experiment the water intake of hens on these diets was examined. Data were analysed by factorial analysis of variance, and the relationship between performance and dietary energy concentration was examined by regression analysis.

2. The use of low energy diets (10.5 to 11.3 MJ ME/kg) decreased egg production in both seasons, but pelleting diets improved egg production and egg weight in summer. Egg weight was not affected by energy density in winter, but decreased in the summer when energy density increased.

3. In winter, food consumption was not affected by the dietary ME, while in summer food consumption increased when the dietary ME increased. Therefore, energy intake was not the same at all energy densities, but tended to increase as the energy density increased.

4. In summer, pelleting improved food efficiency and egg production and increased water consumption and the ratio of water to food intake. Water intake and water: food ratio decreased with increasing dietary energy concentration.  相似文献   


3.
1. Twenty one diets were formulated to contain three levels of energy (11.7, 12.5 and 13.4 MJ ME/kg), 4 levels of protein (starter 200, 220, 230 and 250 g, grower 180, 200, 220 and 240 g, and finisher 160, 180, 190 and 210 g/kg) and two concentrations of limiting amino acids (proportion of diet and proportion of protein) in each phase of growth, 0 to 3, 3 to 6 and 6 to 8 weeks of age. Each diet was fed to two pens of 15 broilers.

2. The house temperature ranged from 45°C to 51°C as maximum and 17°C to 22°C as minimum; the relative humidity ranged from 19 to 65.

3. Birds fed low energy (11.7 MJ/kg) and high protein (250, 240, 210 g/kg) diets with the National Research Council (1977) inclusion rates of lysine and sulphur amino acids in starting, growing and finishing phases of growth, attained significantly higher weight gains.

4. High energy, high protein (13.4 MJ/kg, 250, 240, 210 g/kg) diets gave greater efficiencies of food utilisation than low energy, low protein (11.7 MJ/kg, 200, 180, 160 g/kg) diets.  相似文献   


4.
Groups of 10 male, 10 female and 10 unsexed broiler chickens were given eight diets with energy concentrations ranging from 2.3 to 3.6 Mcal ME/kg in two experiments. Diets with a metabolisable energy concentration of about 3.1 Mcal/kg were found to be optimal for growth to a specified live‐weight. Carcass analysis gave much smaller values for nitrogen retention than did estimates from food intake and excreta. Retention measured by the latter method was influenced by the energy concentration of the diets.

Body composition was influenced by both dietary energy concentration and sex. In general, the energy and fat content of the carcass increased with increasing dietary energy concentration although there were overall differences in fat content between male and female chickens, and also between birds in experiment 1 and experiment 2.

Tritiated water was used to predict body water space enabling body composition to be estimated. Comparisons between determined body water content and tritiated water space showed that the former was overestimated, on average, by 18%. Residual standard deviation of prediction equations based on 240 chickens was 52.6 g for water space, 21.4 g for protein and 34.6 g for fat.  相似文献   


5.
1. Two environmentally‐controlled houses, one set at constant 21°C (low temperature, LT) and the other set at diurnally cycling 21°C to 30°C (high temperature, HT), and two dietary energy concentrations of 13 MJ ME/kg (low energy, LE) and 13.8 MJ ME/kg (high energy, HE) were used to study nitrogen and energy retention in the edible carcase of male and female broilers slaughtered at 34 and 54 days.

2. Carcase nitrogen was higher in males than in females, and in birds reared at LT than in those reared at HT.

3. Birds at LT and on HE diet, regardless of sex, retained more energy as fat in their carcases than those at HT and on LE diet respectively.

4. Maintenance energy requirement averaged 6.70, 7.67, 7.43 and 9.01 kJ per g metabolic body size (kJ/gW 0.66) for broilers at HT and LT up to 34 d and at HT and LT up to 54 d, respectively.

5. There was a similar increase with age in the energy requirement for growth but with requirements of broilers at LT consistently lower than for those at HT.  相似文献   


6.
1. A total of 2560 male and female Ross broilers were raised to 42 days of age in a 2 × 2 treatment factorial arrangement experiment to investigate the influence of different degrees of physical activity and dietary energy on broiler performance, abdominal fat content, carcase yield and sensory quality.

2. Vertical fans were used to force the treatment birds to walk 3 to 4 times as far as the normal activity birds; birds were fed a normal and a high energy diet (12.55 compared with 13.81 MJ ME/kg) with the same energy/protein, energy/lysine and energy/methionine + cystine ratios.

3. High activity birds had greater body weight ( + 4.1%), food intake ( + 5.1%) and ME intake ( + 5.1%) than normal activity birds. Birds receiving high energy diet had a lower food conversion and food intake than birds receiving normal energy diet. There were no significant differences in body weight or ME intake between birds with different diets.

4. Slaughter yields, both absolute and relative to live body weight, were affected by activity or dietary energy to varying degrees. Breast meat was increased with more activity. The absolute weight of abdominal fat was independent of activity and in males the relative weight of abdominal fat was decreased in high activity birds.

5. Different degrees of activity and dietary energy had only minor influences on broilers' sensory quality.  相似文献   


7.
Eight diets with metabolisable energy (ME) concentrations ranging from 9–1 to 15–3 MJ/kg were given to groups of five chickens kept in respiration calorimeters for 3 to 4 d. Availability of ME ranged from 57% to 79%. One diet differed from the others, but for those groups of chickens on the other seven diets availability of ME was 80% when energy balance was negative and only 60% when positive.

Protein synthesis appeared to continue when chickens were in negative energy balance and fat was frequently catabolised when birds were in positive energy balance, apparently to support protein synthesis.  相似文献   


8.
1. The metabolisable energy (ME) contents of dried brewers grains and of dried brewers grains with yeast were 5.51 +0.69 and 7.20 ±0.69 MJ/kg dry matter or 0.25 + 0.03 and 0.34 + 0.03 of their respective gross energy contents.

2. In these respective ingredients, the apparent digestibility coefficients of protein were, 0.66 + 0.08 and 0.69 + 0.08; of fat, 0.49 + 0.16 and 0.64 + 0.16; of dry matter 0.14 + 0.05 and 0.24 + 0.05, while fibre and nitrogen‐free extract (NFE) were not digested.

3. In balanced low‐protein diets formed by adding glucose to a high‐protein diet, the ME content of glucose was 15.12 + 0.44 MJ/kg dry matter or 0.97 ± 0.03 of its gross energy content, while the apparent digestibility coefficient of its NFE was 0–99 + 0–02, and that of its dry matter was 1.02 + 0.04.

4. Imbalancing diets greatly by removing or adding glucose to a balanced diet did not affect the nutrient digestibility or the ME of glucose, indicating that the basic assumption of linearity of these measurements with dietary content of the test ingredient was valid.  相似文献   


9.
1. A diet containing 110 g crude protein/kg caused smaller losses in egg weight, numbers and body weight in Babcock B300 layers than diets containing 90 g protein/kg, 6.56 MJ ME/kg or 7.90 MJ/kg.

2. The sequence of repletion of depleted birds was body weight, egg weight and egg number. For the first alone more than 420 kJ/d was required, for body weight and egg weight more than 630 kJ/d and for all three more than 1170 kJ/d.  相似文献   


10.
1. An experiment was conducted to study the effects of feeding graded concentrations of metabolisable energy (ME) and crude protein (CP) on the performance of layers. Nine diets with three concentrations each of ME (10.04, 10.67 and 11.30 MJ/kg) and CP (150, 165 and 180 g/kg) in a 3 × 3 factorial arrangement of treatments were formulated.

2. A total of 5544 White Leghorn (WL) pullets (20 weeks of age) were housed in 4-bird colony cages and 22 adjacent cages constituted a replicate. Each diet was fed ad libitum to 7 replicates from 21 to 72 weeks of age. Production variables were recorded in 13 laying periods of 28 d each, and the data were pooled into three production phases, namely initial (21–32 weeks), peak (33–52 weeks) and post-peak (53–72 weeks).

3. No interaction was observed between ME and CP for egg production (EP), food intake (FI), food efficiency (FE), egg weight (EW), egg mass (EM) and body weight gain.

4. The EP, EW and EM during the initial phase of production were not affected by dietary ME concentrations, while the EW and EM improved with increasing concentrations of dietary CP from 150 to 165 g/kg.

5. During the peak production phase, improvements in EP (ME and CP), FI (ME), FE (ME, CP), EW (ME) and EM (ME, CP) were observed with increasing concentrations of energy and protein to 11.30 and 180 g/kg diet, respectively.

6. EP, EW and EM were unaffected by dietary variation in concentrations of ME and CP during post-peak production phase, but the FE improved and FI reduced with increasing dietary concentrations of these nutrients.

7. It is concluded that the optimum concentrations of ME for WL layers during the 21–32, 33–52 and 53–72 weeks of age are 11.30, 11.30 and 10.04 MJ/kg diet, respectively. The corresponding values for CP in diets are 180, 180 and 150 g/kg.  相似文献   


11.
1. An experiment was conducted to determine the effect of different dietary protein contents on the performance of naked neck (Na/na) and normally feathered (na/na) broilers.

2. Chicks from the two genotypes were reared in wire‐floored cages and divided at random into 3 groups. Birds were fed on high protein (HP, 12.99 MJ ME, 238 g crude protein/kg and 12.94 MJ ME, 216 g crude protein/kg from 0 to 3 and 3 to 7 weeks, respectively), medium protein (MP, 12.99 MJ ME, 219 g crude protein/kg and 12.87 MJ ME, 201 g crude protein/kg from 0 to 3 and 3 to 7 weeks), and low protein (LP, 12.94 MJ ME, 205 g crude protein/kg and 12.75 MJ ME, 184 g protein/kg from 0 to 3 and 3 to 7 weeks) diets.

3. The LP diets resulted in a significantly lower daily body weight gain of males from 0 to 3 weeks. Dietary protein content had no effect on body weight gain from 3 to 7 weeks, body weight at 7 weeks, and the food intake of birds. Carcase composition of birds from both genotypes was unaffected by dietary protein.

4. Naked neck birds had significandy higher body weights at 7 weeks. Yields of carcase and breast of Na/na males were significantly higher than those of na/na males. There were no significant differences between females from the two genotypes as regards carcase yield.

5. It was concluded that the dietary protein requirements of naked neck birds were similar to those for normally feathered birds.  相似文献   


12.
1. A total of 720 1-d-old broilers were used in a 28 d experiment to determine the effects of probiotic supplementation in diets with different dietary nutrient densities.

2. Birds were randomly allotted to one of the 4 treatments in a 2 × 2 factorial arrangement (12 replicateswith 15 broilers per replicate) with two levels of nutrient density [high nutrient density (metabolisable energy (ME) 12.7 MJ/kg and crude protein (CP) 230.3 g/kg for 1–7 d; ME 13.2 MJ/kg and CP 220.3 g/kg for 8–28 d) or low nutrient density (ME 12.1 MJ/kg and CP 220.2 g/kg for 0–7 d; ME 12.6 MJ/kg and CP 209.8 g/kg for 8–28 d)] and 0 or 2 g/kg probiotics (1.0 × 1010 viable spores/g of Bacillus subtilis endospores and 1.0 × 109 viable spores/g of Clostridium butyricum).

3. The high-nutrient-density diet increased body weight gain (BWG), feed conversion ratio (FCR), serum cholesterol and triglyceride concentration relative to the low-nutrient-density diet. High-nutrient-density diet reduced water loss ratio of breast muscle, liver and fat relative to body weight compared to low-nutrient density-diet. The inclusion of probiotics increased BWG and feed intake throughout the experiment. Dietary probiotics increased the percentage of blood lymphocytes and relative weight of spleen and bursa of Fabricius when compared to the non-probiotic treatment. The inclusion of probiotics decreased serum cholesterol and triglyceride concentrations and lightness (L*) value of breast meat compared to the non-probiotic-supplemented diet.

4. In conclusion, high dietary nutrient density increased growth performance and serum cholesterol and triglyceride concentrations in broiler chickens. The inclusion of probiotics increased growth performance but reduced serum cholesterol and triglyceride concentrations. The positive effect of probiotic supplementation on growth performance was reduced by the high-nutrient-density diet during the first week of life.  相似文献   


13.
1. Individually caged Single Comb White Leghorn hens simultaneously received two diets which allowed selection of certain nutrients: these “ split‐diets “, essentially provided concentrated sources of either protein and energy (191 g crude protein, 12.82 MJ ME and 4.7 g Ca/kg diet), or calcium (107 g CP, 7.28 MJ ME and 131 g Ca/kg).

2. During four, 28‐d periods of lay, birds offered these split‐diets consumed some 7% less food in total than did control birds receiving a conventional diet ad libitum.

3. Calculation of nutrient intakes showed that birds on the split‐diets consumed significantly less protein, energy and calcium than the control birds.

4. Giving split‐diets also resulted in superior shell quality; treatment differences were also noted in the timing of oviposition.

5. It is suggested that the voluntary reduction in food intake noted for birds offered split‐diets is associated with an appetite for calcium.  相似文献   


14.
1. This study was conducted to investigate the effects of two lipotropic factors (choline and carnitine) on growth performance, oxidative stability of leg and breast muscles and carcass characteristics in broiler chickens fed diets differing in metabolisable energy (ME) levels.

2. A total of 540 one-d-old Ross 308 broiler chicks were allotted to 9 experimental diets, including three ME levels (control, or 0.42 or 0.84 MJ/kg higher ME) and three types of supplemental lipotropic factors (control, 1000 mg/kg of choline or 100 mg/kg of carnitine) as a 3 × 3 factorial arrangement of treatments. Average daily feed intake (ADFI), average daily gain (ADG) and feed conversion ratio (FCR) were recorded during the starter (1–14 d of age), grower (15–28 d of age) and finisher (29–42 d of age) periods.

3. Results showed that the increase in dietary ME level had no impact on ADFI during the starter and grower periods. In the finisher period, increasing dietary ME decreased (P < 0.001) ADFI. Raising dietary ME level by 0.84 MJ/kg resulted in the greater ADG during the grower (P < 0.05) and finisher (P < 0.001) periods. Moreover, an improvement in FCR was observed with feeding the +0.84 MJ/kg diet. Dietary supplementation of lipotropic factors improved FCR values in birds fed the control and +0.84 MJ/kg diets during the grower and finisher periods (P < 0.01).

4. Dietary supplementation of both choline and carnitine increased (P < 0.05) moisture content of leg muscle, although malondialdehyde content of leg muscle was decreased (P < 0.01) in the presence of both lipotropic factors. Dietary supplementation of carnitine decreased (P < 0.01) leg fat content, and this effect was more obvious with higher ME levels, giving a significant ME × lipotrope interaction (P < 0.05). Higher dietary ME level (+0.84 MJ/kg) reduced (P < 0.05) protein content of breast muscle, but this factor was increased (P < 0.05) by dietary supplementation of choline.

5. Although dietary ME level had no marked effect on carcass yield and internal organ weight, supplemental choline increased (P < 0.01) carcass yield.

6. The results from this trial indicated that dietary supplementation with lipotropic factors can improve feed efficiency in high energy diets. In addition, oxidative stability of leg/breast muscles was improved as a result of dietary supplementation with choline or carnitine.  相似文献   


15.
1. Crude glycerol from biodiesel production was offered ad libitum to broiler chickens in a 21-d feeding and digestibility trial. The study was designed as a 3*2?+?1 factorial design with 3 concentrations (33, 67, 100?g/kg) of glycerol from 2 sources, A and B (PRS Environmental Ltd and John Thompson and Sons Ltd) and a control diet. The diets were formulated to contain apparent metabolisable energy (AME) of 12·95?MJ/kg (assuming 14·6?MJ/kg for glycerol).

2. No significant interactions occurred, so only the main effects were discussed. At 7–14?d, feed conversion ratio (FCR) showed a significant linear response with increased glycerol inclusion. However quadratic responses on FCR were observed for the 21–28?d period and 7–28?d.

3. Glycerol digestibility was significantly greater with birds offered the 67?g/kg and 100?g/kg glycerol-based diets in contrast to the digestibility of 33?g/kg glycerol-based diets.

4. Glycerol inclusion level also had an effect on AME, which increased linearly with increasing glycerol inclusion. Birds offered the diets containing glycerol also required less energy per unit gain in contrast to birds offered the control diet.

5. When examining the effect of source of glycerol, source A glycerol resulted in the highest AME (15·20 vs. 14·72?MJ/kg). There was no significant effect of glycerol source on the other performance parameters.

6. Glycerol digestibility was significantly greater with glycerol from source B (John Thompson and Sons, Ltd) with a mean value of 0·848 in contrast to source A (PRS Environmental), which had a somewhat lower mean glycerol digestibility of 0·757.

7. In conclusion, glycerol source did not affect performance and increasing level of glycerol improved FCR, with 67?g/kg inclusion resulting in the most efficient conversion of feed to gain without any negative effects upon nutrient digestibility.  相似文献   


16.
1. The ‘extra caloric’ effect of added soyabean oil, as reflected in improved body weight gain, food utilisation, metabolisable energy or net energy deposition in the body was determined.

2. Two diets were formulated to contain 12.1 MJ/kg, one with no added fat and the second with 30 g/kg soyabean oil. Addition of oil improved body weight gain by 6.9% (P< 0.05). Two other diets were formulated to contain 13.0 MJ/kg, one with 30 and one with 60 g/kg added soyabean oil bringing the total fat in the high energy, high fat diet to 84 g/kg. Addition of oil in this case improved weight gain by only 3.4% (ns). Addition of soyabean oil increased the apparent digestibility of total dietary fat and reduced that of starch.

3. The effect of soyabean oil supplementation on mash diets at both energy concentrations or to the pelleted diet (formulated to contain 12.1MJ) on AMEn was consistently positive although not significant. Addition of soyabean oil improved net energy deposition in the body by 17% within the 12.1 MJ/kg diets, (30 g/kg soyabean oil addition) (P< 0.05), but was reduced by 2% (ns) within the 13.0 MJ/kg diets (60 g/kg soyabean oil addition).

4. Supplementing a pelleted diet formulated to contain 12.1 MJ/kg, with 30 g/kg soyabean oil, improved food utilisation (P< 0.05). The ‘extra caloric’ effect of added soyabean oil, defined as the beneficial effect of the oil above that predicted from its energy value, varied according to the parameter chosen to express this effect and was influenced by the concentration of added soyabean oil and the dietary energy.  相似文献   


17.
1. Dry rabbit excreta were found to contain 188.1 g crude protein, 6.6 g non‐protein nitrogen, 0.3 g ammonia, 89.8 g moisture, 8.0 g ether extractives, 135.2 g crude fibre, 266.9 g ash and 19.18 MJ gross energy/kg. Methionine and lysine contents were 3.95 and 4.29 g/100 g protein, respectively.

2. In one experiment, 0, 50, 100 or 200 g rabbit excreta/kg were substituted for maize in a broiler diet. Chickens receiving the diet containing 200 g rabbit excreta/kg gained significantly less weight to 8 weeks of age than those receiving other diets.

3. In a second experiment, 0, 100, 150 or 200 g rabbit excreta/kg were substituted primarily for maize in a broiler diet to provide equal energy and protein contents. Weight gains to 8 weeks of birds receiving these diets did not differ significantly. The uncorrected metabolisable energy content of the excreta was 9.15 MJ/kg.

4. There were no gross pathological changes in the birds fed on the experimental diets.  相似文献   


18.
1. The effects of post‐brooding temperature (15 to 27 °C), age (42 to 56 d) and dietary nutrient and concentration energy (11.7 to 13.3 MJ/kg for the finisher diet) on the cumulative food intake and body weight responses of broilers were combined in a predictive simulation model, using multiple regression techniques.

2. An economic model of these responses was developed in which the temperature and age at slaughter are optimised, given food and live body weight prices.

3. If a finisher diet of 13.3 MJ ME and 199 g protein/kg costing 150 £/tonne is fed, and provided the grower diet contains 13.5 MJ and 221 g protein/kg, the optimum temperature is 21 to 22 °C for male and female broilers slaughtered at 61 and 54 d respectively with a live body weight value of £0.50/kg.  相似文献   


19.
Two trials were conducted with unsexed broilers to compare a net energy (NE) system and a metabolisable energy (ME) system on least‐cost broiler diet formulation, broiler performance and economic efficiency. Both energy systems were compared in the range of 3000 (2161) to 3400 kcal ME/kg (2560 kcal NE/kg) using rations with increasing energy concentration of about 100 kcal/kg food.

The two different energetic evaluation systems had considerable effect on dietary composition, the penalty cost of rejected ingredients, the marginal profit of some limiting constraints and the position of the least‐cost nutrient concentration. The starter and finisher rations, based on NE values, were on average 4.77 and 2.43 BF2/100 kg cheaper, respectively than those based on ME values. For equal NE contents, they contained 50 to 70 kcal less ME/kg and 1% less crude protein.

The broiler performances were on average better on the NE‐diets. The mean difference of 20 to 30 g in body weight was significant at 4 and 6 weeks (P < 0.01 and P < 0.05).

Regression analysis indicated no significant effect of rising energy concentration on food intake with the ME‐diets, but a significant (P < 0.05) linear decrease with the NE‐diets of 1.16 ± 0.34 and 1.72 ± 0.37 g/chick d at 6 and 8 weeks respectively for every 100 kcal/kg rise in the NE content of the ration. As a result body weight at 6 weeks improved linearly per increment of 100 kcal NE/kg with 37.2 ± 3.2 g (P < 0.05) on the ME‐diets and with 18.8 ± 6.8 g (P = 0.08) on the NE‐diets.

The efficiency of food utilisation, although slightly better on the NE‐diets, was not significantly affected by the energy systems. As expected, linear improvements (P < 0.001) of respectively 58 ± 6 and 62 ± 11 g food/kg weight gain at 6 and 8 weeks were noted for every increment of 100 kcal NE/kg diet.

Returns over food costs were for the whole energy range higher on the NE‐diets (average 0.66 BF/chick, variation 1.01 to 0.23 BF/chick). Gross profit increased with rising nutrient density from 16.33 to 17.97 BF/chick on the ME‐diets and from 17.34 to 18.23 BF/chick on the NE‐diets. The data illustrate that the economical efficiency of broiler production can be considerably improved by taking into account the effect of both energy content and energy system.  相似文献   


20.
1. Salseed meal contains 98 g crude protein, 22 g ether extractives, 450 g available carbohydrate and 117 g tannins per kg.

2. From the chemical analysis the metabolisable energy (ME) content of salseed meal would be expected to be 11.22 MJ/kg. In vivo assay with chicks yielded values considerably less than this, 7.1 MJ/kg being found at an inclusion rate of 150 g/kg diet.

3. As the inclusion rate of salseed meal was increased to 300 g/kg, dietary ME and the digestion and retention of dietary protein decreased.

4. More than 50 g salseed meal/kg in the diet of chicks resulted in poor growth rate and food conversion.  相似文献   


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