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. 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. Weight gain, rate of lay, mean egg weight, egg output, shell thickness and total food intake were unaffected by the treatments in either stock.
3. The mean intake of the complete diet was 825 and 845 g/kg of total intake with standard deviations between individuals of 73 and 61 g/kg respectively in the two stocks.
4. In birds given a choice of diet the one selected was related to output (P < 0.01). 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. 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
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. A total of 144 dwarf hens (38 weeks of age) from the same hatch were randomly divided into 12 groups of 12 birds (4 dietary treatments × 3 replicates).
3. A 2 × 4 factorial design was used to study the effect of 2 lines (Factor A) and substitution of soybean meal (SBM) with 4 concentrations (0, 10, 15 and 20%) of sunflower meal (SFM) [Factor B] on egg quality traits of dwarf dam line hens.
4. All the diets were designed to be isocaloric (11?3 MJ ME/kg) and isonitrogenous (180 g/kg crude protein) The duration of the experiment was 12 weeks.
5. Analysis of variance indicated a highly significant line effect. There were non-significant effects of substitution of soybean meal with different concentrations of sunflower meal on egg quality traits except for Haugh unit.
6. White plumaged dwarf broiler breeder dam line produced significantly fewer, but larger, eggs than coloured dwarf dam line hens. 相似文献
2. By regression analysis of absorption on intake, the true digestibilities of the crude protein, using colostomised birds, were calculated to be 85.2 and 72.0%, those of the crude fat 94.4 and 89.7% and those of the carbohydrate 82.0 and 75.5% for triticale and rye respectively.
3. The classical metabolisable energy values of the triticale and rye samples were found to be 14.08 and 12.51 MJ/kg (3.36 and 2.99 Mcal/kg) respectively.
4. It is concluded that triticale is a better food source for the chicken than either wheat or rye. 相似文献
2. Daily intramuscular injections of 2 and 4 mg/kg of CORT for a 5‐d period in both 2‐ and 5‐week‐old chickens resulted in increases in total food, protein and energy intakes. This led to a decrease in protein accretion in older but not younger chicks, an increase in total lipid contents of the carcase at both ages, and produced changes in internal organs.
3. CORT significantly reduced body weight gain of young but not old chickens, suggesting that mature birds respond better than young ones to the physiological changes caused by treatment, by making subsequent appropriate food choices.
4. Administration of CORT in young chicks increased wheat intake at 2 and 4 h after injection, while in older birds a similar increase was maintained up to 24 h after injection. Intake of HP food was decreased by both doses of CORT in young chicks but there was no significant effect in older chickens.
5. Changes in energy: protein ratio in the chosen diet appeared at 4 h after treatment in old chickens and at 24 h in younger chicks.
6. The results suggest that birds are able to detect metabolic changes caused by CORT administration and attempt to redress them by modifying their food pattern. The time course of the response of birds to these changes is age related. However, the food selection pattern did not completely compensate for the physiological defects. 相似文献
2. The proportions of ingredients eaten by the chickens given a free choice varied widely during the first 56 h of the trial. Thereafter, the proportions did not vary widely and birds given the free choice ate approximately ½ of their intake as whole wheat, ? of their intake as concentrate (high protein meals plus vitamin and mineral premixes), and 1/7 of their intake as whole sorghum each week for the three‐week trial period.
3. The nutrient composition of the free‐choice diet selected by the birds over the trial period averaged 12.09 MJ ME/kg feed, 210 g/kg crude protein, 14 g/kg calcium and 7 g/kg phosphorus.
4. At the end of the trial the average live body weights of the birds differed significantly according to method of feeding, in the descending order of pellets > mash > free choice.
5. The empty gizzard weight of birds differed significantly according to the method of feeding, in the descending order of free choice > mash > pellets.
6. The plucked empty bodies of birds given the free choice had a significantly lower concentration of crude protein than the plucked empty bodies of birds fed on mash or pellets. There were no significant differences between the treatments in the plucked empty body concentrations of fat, calcium or phosphorus.
7. Financial analysis indicated that free‐choice feeding was more profitable than feeding mash or pelleted diets to broiler chickens by 3.6% and 33.4% respectively. 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. The decrease in hatchability that occurred on the high protein (27.0 g CP), low energy (1.52 MJ AME) allowance from 26 to 36 weeks of age was due to an increase in the percentage of dead embryos in the second week of incubation and an increase in the number of “pipped” eggs at the end of incubation.
3. The low hatchability of eggs from birds on the 1.88 MJ AME allowance from 37 to 64 weeks could be related to the incidence of deaths in the first 5 d of the incubation period.
4. Malformations and malpositions of the embryo were not affected by maternal energy or protein allowance. 相似文献
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
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
2. Replacing up to 344.3 g maize/kg with sweet potato did not significantly affect body weight, food intake, food conversion, nitrogen retention, mortality and relative weights of body parts at 10 weeks of age.
3. Whereas crude protein contents of liver, gizzard, heart, lung and breast were not significantly affected by the diets, fat contents were significantly decreased by the replacement of 344–3 g maize/kg with sweet potato. 相似文献
2. Six diets varying in protein from 160 to 300 g/kg and containing approximately 11–72 MJ/kg ME were fed for 5 weeks and analysed for dry matter, protein, fat and ash.
3. Treatments affected carcase weight, dry matter, protein, ether extract and ash
4. The water content of the carcases decreased with increasing dietary protein concentrations, while the carcase protein content increased with higher dietary protein. The carcases with the highest fat content were obtained from quail receiving the low protein diet. 相似文献
2. A SAA requirement of about 750 mg/hen d, of which about 425 mg was methionine, was found to be adequate for birds producing on average 51 g egg mass per hen d over 52 weeks. The SAA requirement was found to be higher for maximum efficiency of food utilisation than for maximum egg yield.
3. A diet containing 140 g protein/kg adequately supplemented with methionine and lysine, could sustain laying performance almost identical to that achieved on a diet containing 167 g protein/kg.
4. In diets with 140 g protein/kg the addition of 0.5 to 3.5 g dl‐methionine/kg diet in excess of the requirement did not affect egg production adversely, but food conversion efficiency was decreased. 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
The mean body weight was similar in both breeds at 1 d of age, while at 8 weeks the Italian breed was slightly heavier than the Landes. The weekly percentage weight gain for the two breeds were similar, however.
The efficiency of food conversion was higher in the first 4 weeks than in the second 4 weeks in both breeds. The daily food consumption and the efficiency of food conversion of the Italian goslings were lower than those of the Landes throughout the period of the study. 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