Differences in dietary energy caused significant differences in egg production and weight in two of the experiments. Increasing ME of the diet caused significant decreases in food intake in two experiments and significant improvements in the efficiency of food conversion in all experiments. Dietary energy was found to affect body weight gains significantly in only one experiment. Energy intake during the summer was 10 to 15% lower than during the winter or spring.
It is concluded from this study that hens of the strain used, laying at a rate of 70 to 75% and weighing about 1·65 kg in a semi‐arid continental climate, require approximately 300 kcal (1·25 MJ) per bird‐days. This requirement varies with the season, being approximately 20 kcal (84 kJ) higher during the winter and 20 kcal lower during the summer. 相似文献
The mean fasting heat production (±SE) was 92.3 (±5.0) kcal/kg d or 113.4 (±5.7) kcal/kg3/4 d. The relationship between energy balance (T) and ME intake (X) was calculated to be Y = 0.851X—92.9 indicating that the maintenance ME requirement was 109.1 kcal/kg d and that the net availability of the ME was 85.1 per cent. The efficiency of energy utilisation in relation to plane of nutrition and to the amount of protein and fat deposited is discussed. 相似文献
2. The average values of nitrogen lost, endogenous energy losses (EEL) and endogenous energy losses corrected to zero‐nitrogen balance (EELn) were found to be 1.18 g, 62.13 kJ and 21.51 kJ/bird/48h, respectively, from adult cockerels given an energy supply as 50 g glucose during starvation.
3. The nitrogen‐corrected apparent metabolisable energy (AMEn) values for feed‐grade lentil, lentil bran and wild vetch seed, respectively, were 6.84, 3.05 and 14.31 kJ/g dry matter. The nitrogen‐corrected true metabolisable energy (TMEn) values for the respective feedingstuffs were 7.44, 3.65 and 14.90 kJ/g dry matter. 相似文献
2. Substituting triticale for maize, weight for weight, but not on a iso‐nitrogenous basis, in a groundnut oil cake (GNC) starter diet improved weight gain (P < 0.05) when the substitution exceeded 75% without affecting the protein efficiency ratio (PER).
3. A similar substitution in a soybean oil meal diet, improved weight gain (P < 0.05) at 50% or more but PER declined (P < 0.05).
4. The net protein utilisation and protein retention efficiency values of the diets in which maize protein was replaced by triticale protein were significantly reduced.
5. The maize‐GNC diet was equally limiting in methionine and lysine while the triticale‐GNC diet was not.
6. The growth and food efficiency obtained with a triticale‐GNC diet was higher (P < 0.01) than with the maize‐GNC diet but not with a maize‐GNC supplemented with fish meal and methionine.
7. It is concluded that triticale could quantitatively substitute maize in the starter diets. 相似文献
2. In the first experiment female broiler chicks were fed on 11 experimental diets. Two iso‐energetic basal diets (diets 1 and 2) were prepared with 200 and 160 g CP/kg and 7·6 and 6·0 g threonine/kg respectively. Both diets contained 11·5 g lysine and 8·7 g sulphur‐containing amino acids/kg. Diet 3 was composed of diet 2, supplemented with all essential and non‐essential amino acids (EAA and NEAA, respectively) except threonine, to the concentrations of the amino acids in diet 1. The NEAA were added as a combination of glutamic acid and glycine. Diets 4 to 11 had the same compositions as diet 3, but contained increasing amounts of threonine.
3. For birds fed on diet 2, gain was significantly lower and food/gain ratio was significantly higher than for birds fed on diet 1. Supplementation with EAA, NEAA and threonine to the same concentrations in diet 1 resulted in a performance similar to that found on diet 1.
4. In experiment 2, male and female broiler chicks both received 10 experimental diets. Diet 1 contained 220 g CP/kg and 8.5 g threonine/kg, diet 2 contained 160 g CP/kg from natural raw materials and 6 g threonine/kg. Both diets contained 12·4 g lysine and 9·3 g sulphur‐containing amino acids/kg. Basal diet 2 was supplemented with all EAA and NEAA to the concentrations of basal diet 1, except for threonine. Diets 3 to 10 had the same compositions as the supplemented diet 2, but contained increasing amounts of threonine.
5. For male and female chicks on diet 2, gain was significantly lower and food/gain ratio significantly higher than those on diet 1. Diet 10 (160 g CP/kg plus all EAA, including threonine, and NEAA supplemented to the concentrations of diet 1) resulted in the same performance as diet 1.
6. The results indicate that, when low protein maize‐soyabean meal diets supplemented with EAA and NEAA with 13·31 MJ ME/kg were fed to male and female broiler chicks until 21 d of age, improvements in gain and food/gain ratio were obtained when the dietary threonine content was increased to 7·25 g/kg. When female chicks were fed threonine‐supplemented diets to 28 d of age, improvement in gain and food/gain ratio was obtained when the threonine concentrations were increased to 6·32 g/kg diet.
7. Curves have been fitted to the data, from which a cost‐benefit analyses can be made and an optimum threonine dose calculated, using local prices. 相似文献
The turkeys obtained 3.2 and 1.7% more metabolisable energy than chicks from the diets used when assessed on a classical ME and N‐corrected ME basis respectively. The difference was smaller when maize formed a major part of the diet than for the other cereals. Higher ME values were also obtained in the older birds but the effect was not reproducible. 相似文献
2. Force‐feeding significantly increased the weight and area of the crop, the weight of the proventriculus, the length and area of the jejunum and ileum, but decreased the weight of the gizzard and the thickness of its caudodorsal thick muscle. Feeding a barley‐based diet also decreased the thickness of caudodorsal thick muscle of gizzard.
3. Force‐feeding enhanced the absorption rates (μmol/cm2) of glucose and L‐methionine in both jejunum and ileum. Ducks fed on a maize‐based diet showed a slightly higher absorption rate of glucose compared to those fed on a barley‐based diet.
4. Force‐feeding caused a significant increase of endogenous non‐protein nitrogen (μg/cm2/h) in both jejunum and ileum and a slight increase of endogenous protein nitrogen in the jejunum. 相似文献
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
2. Ad libitum fed birds laid more and heavier eggs than any of those restricted. A decrease in daily egg output of about 5 g was associated with each 100 kJ decrease in daily intake of metabolisable energy.
3. For the same energy intake, egg output of birds fed on the low‐energy diet was markedly greater than that associated with the medium‐energy diet.
4. The mortality of birds receiving restricted quantities of the medium‐energy diet was two to three times greater than that associated with similar rationing of the low‐energy diet. 相似文献
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
High energy diets of about 1350 k cal./lb. containing 13, 15 and 17 per cent protein and medium energy diets of 13 and 17 per cent protein were fed to colostomised pullets to determine their digestibility, biological value and net protein value. In a further experiment a maize‐fishmeal diet of 1370 k cal. ME/lb. and 17 per cent protein, a soyabean‐maize diet of 1330 k cal. ME/lb. and 14 per cent protein and the latter diet supplemented with methionine and/or lysine were also examined. The mean BV and NPV values of the diets considered in Experiment 1 were 60 and 52 respectively.
Addition of methionine to the maize‐soyabean diet increased the BV from 43.9 to 61.6, the addition of lysine to 43.0 and the addition of both to 67.1.
A factorial method of calculating the daily protein requirement of the pullet based on the data for MFN and EUN and the NPV of each diet is presented. The estimate of 13.3 g. protein per day for the hybrid pullet is compared with other estimates in the literature. 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. Food intake, heat production and maintenance energy requirement all increased linearly with decreasing temperature. Metabolisability of the diet was only 13.8 kJ/g at 35 °C, compared with a mean value for all treatments of 14.1 kJ/g.
3. Energy retention and nitrogen (N) retention (g/d, or % dietary N) were maximal at 22 and 16 °C, however the amount of energy deposited as protein remained relatively constant below 30 °C.
4. Net availability of metabolisable energy was calculated in two ways: by calculating the increase in heat production of fed birds above their starvation values giving a mean value of 0.82; this was similar to the mean regression coefficient which included starvation data, and related ME intake and energy retention; but without these data availabilities ranged from 0.45 at 35 °C to 1.0 in the cold.
5. Acclimation or alternating of temperature had very few significant effects, however there were temperature x acclimation effects on N retention and heat production. Similarly alternating temperature significantly increased food intake and heat production at high temperatures, but decreased metabolisability of the diet to 13.7 kJ/g at 35 °C from an overall mean of 14.1 kJ/g. 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