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. Egg production and egg mass output were higher with the 190 g protein/kg diets.
3. Lower‐energy diets gave better egg production, while higher‐energy diets containing 190 g protein/kg improved food conversion efficiency.
4. Separation of protein and calcium constituents tended to give better egg production, food conversion efficiency, shell thickness and egg mass output. 相似文献
2. Cumulative food consumption and body weight at 42, 49 and 56 d decreased with increasing temperature.
3. There were no interactions between temperature and dietary nutrient concentration. 相似文献
2. Irrespective of the Neepawa wheat used or lysine added, maximum growth was not obtained with diets containing 220 g protein/kg.
3. There was no response to lysine added to diets of 280 g protein/kg containing the 145 g protein/kg Neepawa wheat, but there was such a response in such diets containing the 210 g protein/kg wheat.
4. It is concluded that the Neepawa wheat containing 210 g protein/ kg, when supplemented with lysine, can replace soyabean meal in diets for young turkey poults. 相似文献
2. All diets were formulated to contain 10.6 MJ ME/kg.
3. Three pens of birds receiving the diet containing 23 g calcium/kg were also offered grit free choice containing 280 g calcium/kg.
4. There were no effects of treatment on food consumption or reproductive performance. 相似文献
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
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
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
2. In diets of 160 g protein/kg without added lysine, high‐protein wheats caused lower rates of production and egg size than conventional wheats in White Leghorns. Lysine supplementation of the former diets eliminated these differences.
3. The improvements in egg production and egg weight were significant with 1 g additional lysine/kg and egg production tended to improve further with 2 g additional lysine/kg, as did egg weight with all subsequent additions, but not significantly so.
4. With diets containing high‐protein wheats supplemented with lysine, high egg production and egg weight could be obtained without a protein supplement (e.g. soyabean meal).
5. In broiler‐breeders egg production was lower and food conversion poorer with high‐protein wheat despite added lysine. 相似文献
2. Slaughtering at 54 d instead of 34 d produced broilers with breast and leg weights of 277 and 308 instead of 284 and 319 g/kg carcase respectively, and a higher cutting loss (31 versus 6 g/kg carcass).
3. Males had lower proportions of breast, breast meat and fat, but higher proportions of leg, leg bone, and total meat to fat ratio than females.
4. Cycling high temperature resulted in higher breast, and lower leg proportions than constant low temperature.
5. High dietary energy content increased cutting loss, proportion of breast fat and lowered meat to fat ratio when compared to low energy, but did not affect the flavour of the meat, which was improved by age and high environmental temperature. 相似文献
2. Body weight and feed efficiency were measured weekly from hatch to 56 d of age at which time oesophagus, abdominal fat pad, heart, liver and lungs were removed and weighed. At 35 d of age chicks were inoculated with sheep erythrocytes (SRBC) and antibody titre was measured 6 d later.
3. Chicks fed diet E were heavier than those fed diet A. HH chicks were heavier dian LL chicks wim HL and LH chicks intermediate to the parental lines. LH chicks were heavier than HL ones reflecting large maternal effects.
4. Food efficiencies among stocks and diets were consistent with those for body weight, with HH > LH > HL > LL and E > A. Relative differences between diets were similar across ages and heterosis for food efficiency was about 15%.
5. Relative to body weight, oesophagus and liver weights were heavier in chickens fed diet A than fed diet E. The pattern reversed for abdominal fat pad.
6. Antibody to SRBC antigen was greater in the crosses than in line HH and in cross HL than line LL, with heterosis of 70%. 相似文献
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
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
2. In experiment 1, the SAA requirement for body weight gain increased as dietary protein content increased. Regression analysis indicated a requirement of 38 g SAA/kg protein.
3. In experiment 2 in which lysine supplementation provided a minimum of 10 g/kg, the requirement for SAA per unit of diet increased only slightly as protein concentration increased indicating that below 200 g protein/kg of diet, the SAA requirement increases per unit of protein with supplementation of the second‐limiting amino acid.
4. Abdominal fat percentage declined in a linear manner with each increment of SAA added to diets containing 160 to 200 g protein/kg. Adding methionine to diets containing 240 or 280 g protein/kg did not affect abdominal fat content. A lower limit of abdominal fat was achieved with a protein concentration of 240 g/kg.
5. It is concluded that the requirement for SAA of finishing broiler chickens is directly related to protein content at concentrations of 200 or more g protein/kg but increases per unit of protein at lower protein concentrations when a minimum lysine concentration is specified. Abdominal fat content reaches a minimum between 200 and 240 g protein/kg of a maize‐soyabean meal diet regardless of SAA content. 相似文献
2. Classical metabolisable energy values for the spray‐dried product, at relatively low inclusion rates, ranged from 9.55 to 10.92 MJ/kg dry‐matter (DM) and nitrogen‐corrected values ranged from 8.95 to 10.16 MJ/kg DM.
3. Inclusion of 96 g/kg flash‐dried methanol‐grown bacteria in unpelleted semi‐purified diets marginally increased growth rates, efficiency of food conversion and nitrogen utilisation of chicks, but higher inclusions of up to 290 g/kg caused adverse effects. 相似文献
2. Pullets receiving these two diets displayed a slower, but more uniform growth rate than did birds offered a single conventional diet. Up to 11 weeks of age, control birds consumed significantly more protein while the converse was true from 11 to 20 weeks. These differences are discussed in relation to the stage of sexual maturity.
3. Broilers offered the split‐diets grew more slowly and had an inferior food conversion ratio compared with control birds fed on a two‐stage rearing programme.
4. Among the broilers offered split‐diets, the usual sex differences were not observed for weight gain or carcass fat content. 相似文献
2. The results indicate a requirement for a diet with 240 g crude protein/kg, 9 g methionine plus cystine/kg and 12.97 MJ metabolisable energy/kg for maximum growth and food efficiency up to 8 weeks of age.
3. Though the imported commercial‐strain ducklings grew faster and utilised food more efficiently than the local strain, the general pattern of response indicated that optimum concentrations of nutrients were similar in the two strains.
4. The indicated nutrient contents are different from the recommended concentrations for ducklings in the temperate environment. 相似文献
2. Food intake was measured daily for 21 d. Body composition was determined at 42 d and gains in body mass, protein, fat and gross energy calculated by comparison with a group analysed at 21 d. Heat production was calculated by difference between AME intake and energy gain.
3. Decrease of food mass intake with increased dietary AME concentration limited the increase in AME intake to about 25%, despite the near 2‐fold range of AME concentrations.
4. There was no effect of CP concentration on food mass intake. CP intake was directly related to CP: AME ratio.
5. When body weight differences were taken into account, heat production was independent of dietary AME concentration, but increased by about 8% on the higher‐protein diets.
6. There were strong linear correlations between dietary CP:AME ratio and carcase protein: energy ratio, carcase fat content and carcase protein content.
7. It was concluded that the growing fowl responded to dietary nutrient: energy ratio, and the associated differences in nutrient and energy intakes, by varying the rate of energy deposition as fat, without regulatory variation of energy dissipation as heat. 相似文献
2. The use of SFM resulted in an increase in the height and width of intestinal villi, and a linear decrease in crypt depth. Dry matter digestibility and energy metabolisability decreased in groups fed diets with a moderate (140?g/kg) and high (210?g/kg) SFM content.
3. A decrease in dry matter digestibility and energy metabolisability was most likely the reason for a reduction in body weights of 8-week-old turkeys fed on diets containing 140?g/kg (from 4·17 to 4·01?kg) and 210?g/kg (from 4·17 to 3·93?kg) of SFM.
4. The addition of enzyme resulted in a slight increase in villus height, a significant increase in the number of goblet cells and an increase in digestibility coefficients for crude fat.
5. The results of this study demonstrate that turkey diets can be effectively supplemented with high-quality sunflower meal at a concentration of approximately 70?g/kg. It should be noted, however, that at 8 weeks of age the body weight of turkeys fed on diets containing 140 and 210?g/kg of SFM could be lower by 4 and 6%, respectively, than in those receiving the soyabean meal-based diets. 相似文献
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