In both experiments maximum egg production was obtained from the birds fed the high‐energy diet ad libitum. Restriction of the concentrated diet caused a significant reduction of body weight gain and a statistically insignificant fall in the total weight of egg product and in percentage production in both experiments.
Restriction of the concentrated diet caused improvements of 22 and 18 per cent in the efficiency of utilisation of metabolisable energy in experiments 1 and 2 respectively.
The data are discussed in relation to the relevant literature and the current cost of concentrated sources of energy. 相似文献
2. The inclusion of AA improved egg production, food intake and efficiency of utilisation, and decreased the cost of food per kg egg. The addition of 400 mg AA/kg diet gave the most efficient performance.
3. Palm oil inclusion reduced the effect of heat stress and increased egg production, egg weight, food intake and efficiency of utilisation.
4. When 200 mg AA and 50 g palm oil/kg were used, additive responses were obtained with further improvements in egg production, food cost and efficiency.
5. Ascorbic acid and palm oil when fed alone or in combination reduced the incidence of cracked eggs.
6. Thus, 400 mg ascorbic acid/kg of diet, 50 g palm oil or 200 mg AA plus 50 g palm oil/kg diet ameliorated the effects of heat stress in laying hens. 相似文献
2. There were significant interactions between crude fat and xylanase supplementation on the faecal digestibility of crude fat and crude protein. Fat digestibility was improved by xylanase in both fat type groups but to a greater extent for the tallow diets. However, the effects were found to be significant only for oleic, linoleic and linolenic acids. Similarly, protein digestibility and AMEn values were significantly improved by xylanase, but only for the tallow diet.
3. Heal digestibility of nitrogen and amino acids also were affected by enzyme for both fat type diets, the effect generally being more pronounced for the tallow diet.
4. The deposition of the fat soluble vitamins A and E in livers was significantly increased by xylanase supplementation and was also better for soya oil than for tallow.
5. Xylanase supplementation increased the digestibility of insoluble pentosans whereas for the soluble pentosans the opposite effect was noted.
6. Without xylanase supplementation the tallow‐based diet caused high mortality. Liveweight gain and the efficiency of food utilisation were greatest in the soya oil‐based, xylanase‐supplemented diet, followed by the unsupplemented soya oil‐, supplemented tallow‐ and unsupplemented tallow‐based diets. 相似文献
Only the growing ration containing 1.83 per cent magnesium significantly reduced growth, percentage bone ash and food utilisation during the growing phase (9–20 weeks). In the laying phase (20–40 weeks) significantly greater gains in body weight and percentage bone ash were produced by the birds which had received the growing ration containing 1.83 per cent magnesium.
The magnesium content of the growing rations had no effect on rate of lay, egg weight or egg shell thickness.
Hens fed the laying ration containing 1.96 per cent magnesium gained less body weight, laid fewer and lighter eggs and utilised their food less efficiently than those fed other levels of magnesium.
Egg production and food required per dozen eggs were poorer with the ration containing 1.20 per cent magnesium, but were not statistically different from the rations containing 0.48 or 0.70 per cent magnesium.
Eggs with thinner shells were produced by hens fed the 1.96 per cent magnesium ration at 34 weeks of age than were produced by those fed the 0.48 or 0.70 per cent magnesium rations. 相似文献
2. Replacing groundnut oil cake (GNC) by Niger oil cake (NC) on an isonitrogenous basis, did not affect egg production, egg weight or the amount of food required per dozen eggs.
3. The percentage retention of nitrogen from diets containing 30% GNC or 30% NC was similar.
4. The ME value of NC used was 3025 kcal/kg.
5. It is concluded that NC can replace GNC in layers’ diets. 相似文献
In the first experiment a basal soyabean meal diet (14.3 per cent crude protein) was supplemented with L‐lysine and DL‐methionine, singly and together. Supplementation of the basal soyabean diet with the amino acids caused no significant effects on egg production, mean and total egg weight or food conversion efficiency. None of the soyabean diets proved as satisfactory for egg production or food conversion efficiency as a fish meal control diet (16.9 per cent crude protein).
In the second experiment the effect of adding 0.1 per cent each of L‐lysine and DL‐methionine or 0.2 per cent each of l‐lysine and DL‐methionine to a low fish meal diet (2.5 per cent fish meal) was examined. The addition of 0.2 per cent of each amino acid caused an increase in egg production.
Mean egg weight was improved by the addition of amino acids at both levels although this effect was not statistically significant. Comparison of the low fish meal diets with a fishmeal control diet (10 per cent fishmeal) showed that at the 0.2 per cent addition of amino acids, egg production, total egg weight and food conversion efficiency were better than on the 10 per cent fish meal control diet.
Two breeds, light and medium hybrids were used in both experiments.
The results are discussed with reference to their practical significance. 相似文献
2. In a larger‐scale experiment, isoenergetic and isonitrogenous diets containing 10, 20, 40 or 60 g/kg supplemental maize oil, tallow, coconut oil or fish oil were fed for 5 weeks.
3. Egg weights showed very different responses to the different fats. The responses could be described by quadratic functions that all gave optimum responses with supplemental dietary fat concentrations of about 40 g/kg. Egg weight increased the most with maize oil and was decreased with fish oil at the highest inclusion rate.
4. Measurements of egg components showed a relatively larger increase in albumen weights with maize oil than with other fats.
5. Across treatments, mean plasma oestradiol concentrations were very highly correlated (r = 0.96) with the changes in egg weights over the experimental period.
6. It is concluded that oestrogen is important in controlling egg weight and that the effect of dietary fats in influencing egg weight is mediated by an effect of the fats on oestrogen metabolism. 相似文献
2. The yolk: albumen ratio of the goose egg was higher.
3. The fat concentration in the egg yolk and the protein concentration in the egg albumen were lower.
4. Deposition of dry matter in the embryo and energy expenditure during incubation were similar. In both species, the nitrogen in the embryo exceeded the nitrogen in the egg contents. This is probably due to the utilisation of egg‐shell membrane proteins.
5. Lysine concentration in the goose egg proteins was lower, which was reflected in the hatched gosling proteins.
6. There were high correlations in amino acid concentrations between chicken and goose eggs and between the efficiencies of amino acid utilisation by their embryos, implying that similar metabolic processes are involved in these two species. 相似文献
2. There was no significant difference between the diets in the regression equations relating ME intake and energy retention. There was a slight increase in partial efficiency with increasing ME intake, from 82% at the mean daily intake of 1 874 kJkg W 0.75 to 85% at the highest intake of 2 300 kJ/kg W0.75.
3. Energy retention was greatest at the highest concentration of tallow (140 g/kg) in the diet; there was an indication that availability of ME may be greater for tallow than for oil at a similar ME inclusion rate when compared at the mean daily intake of ME. Without any lipid in the diet, partial efficiency was 77% and energy retention was lower than on the diets with added oil or fat. 相似文献
2. As ME intake increased from 167 to 293 kJ egg production increased.
3. Quadratic relationships between ME intake and egg production, ME intake and egg weight, and ME intake and egg mass (g egg/ bird d) were derived and used to determine the energy required for an acceptable production rate.
4. To maintain a production of 8.3 g egg/bird d (90 eggs/100 bird d with a mean weight of 9.3 g) required 260 kJ ME/bird d. 相似文献
It was found that the best performance was obtained with hens fed the control diet. Gross energetic efficiency of egg production was slightly lower in the birds fed the diets containing arachis or sucrose. It appeared that the lower efficiency was due to the higher mean body weight of birds on these diets. Egg size was significantly increased by feeding the diet containing arachis oil.
Performance of hens given diets containing tallow was unsatisfactory. For each diet egg production was significantly less than that recorded for the control diet and the gross energetic efficiency of egg production was much lower than that on the control diet. 相似文献
2. Live‐weight gains, from 8 to 63 d, were depressed when the diet contained 150 g RSM/kg and there was a highly significant negative correlation between weight gain and inclusion rate of RSM over this period.
3. The efficiency of food utilisation was worse when the diet included 150 g solvent RSM/kg than when it contained no RSM: food efficiency was consistently poorer whenever RSM was included in the diet but the difference was significant only when the diet contained 10 g tallow/kg.
4. Carcasses from birds fed on diets containing 10 g tallow/kg had a better appearance than those from birds on diets containing 30 g tallow/kg, while the flavour of meat from birds fed on a diet containing 150 g solvent RSM/kg treatment was adversely affected. However, up to 100 g solvent RSM/kg may be included in broiler diets without affecting appearance, taste, texture or acceptability of the meat.
5. Inclusion of 50 g or more, solvent RSM/kg reduced growth rate and worsened food efficiency. 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. 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. Significance was achieved for linear regression but not for quadratic regression in both variables; neither rate of inclusion nor age of birds (except for tallow acid oil at 25 d) significantly affected the AMEn or ME of fat. Metabolisable energy of fat (on a dry matter basis) calculated from combined linear regression equations was 19–14 MJ/kg for sunflower acid oil, 18–09 MJ/kg for tallow acid oil and 27–94 Mj/ kg for soyabean acid oil. Differences between sunflower and soyabean acid oils were attributed to variations in unsaponifiable and non‐eluted material of both fats.
3. Abdominal fat pad weight and its relationship to carcase weight were also studied with birds slaughtered at 67 d of age. Chicks given tallow acid oil deposited larger amounts of abdominal fat, and this deposition was directly related to the rate of inclusion of acid oil in the diet. 相似文献
2. Expressed per unit body weight, food and metabolisable energy (ME) intake and weight gain decreased between 2 and 3 weeks of age, but remained constant thereafter.
3. No differences were observed between sexes for any variable measured. Efficiency of utilisation of ME for energy retention was only 0.33. This was mainly because the majority of energy was retained as protein tissue.
4. Nitrogen (N) retention (g/d) increased with increasing dietary N intake but when expressed as a proportion of N intake, declined from 0.46 at 2 weeks to 0.33 at 4 weeks. Fat retention increased substantially during week 4.
5. Carcass analyses showed that fat, protein and ash were higher for quail at 5 weeks than at 2 weeks of age. At 5 weeks carcass fat was only 60 g/kg. 相似文献
2. Increases in food consumption were accompanied by increases in egg production.
3. The food required per dozen eggs was improved by up to 100 g dietary DPM/kg and variation in the sizes of eggs laid depended on the hybrid.
4. Concentrations of DPM up to 100 g/kg did not affect the water‐soluble nitrogen content of the egg but the crude albumen nitrogen content was depressed at concentrations of 80 g/kg or above.
5. Feeding DPM to laying pullets depressed body weight. 相似文献
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
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. 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