Undernourished poults ate more food at any given live‐weight between 6 and 14 weeks of age than did fully fed controls when they were at the same live‐weight. Food conversion was better in undernourished than in fully fed poults in the 6 to 14 week period even after a correction had been made for differences in the food required to maintain different body weights.
Taking the whole period from o to 14 weeks, there was a small improvement in the efficiency of food conversion and a large increase in the efficiency of protein conversion to body weight in favour of the poults which had been undernourished to 6 weeks of age. 相似文献
The percentage protein required for maximum growth in the 6 to 10‐week stage was similar whether turkeys had been fully fed or undernourished from 0 to 6 weeks. But the “ effective “ percentage of protein required in the 6 to 10‐week stage, defined as the level which subsequently allowed maximum body weight at 20 weeks of age, was less for initially fully fed birds. This was because they had smaller growth deficits at 10 weeks and consequently made faster recovery in the limited time allowed.
Turkeys fed 29 and 17 per cent protein or 20 and 22 per cent protein in starter and grower diets respectively reached the same live‐weight at 20 weeks as fully fed turkeys which received 29 per cent protein from o to 6 weeks and 24 per cent protein from 6 to 10 weeks. The compensating turkeys ate about the same total weight of food as fully fed groups, but had a 10 per cent lower total protein intake. 相似文献
The initial body weight of adequately‐fed turkeys bore little or no relationship to 6‐week body weight. Length of lower‐leg at 1 d gave a more reliable prediction of body weight ranking at 6 weeks. In contrast initial body weight was more reliable than initial bone length in predicting body weight ranking at 6 weeks when the low‐protein diet was fed. 相似文献
2. The relative weight of the carcass (body without feathers, skin or intestinal content) decreased from 0.83 of total body weight at hatching to 0.73 at 7 weeks. The skin relative weight increased from 0.12 at hatching to 0.17 at 2 weeks of age and subsequently remained constant. The weight of feathers increased from 0.034 of body weight at hatching to 0.08 at 7 weeks.
3. The fat of the carcass and skin increased during the 7‐week experimental period. The skin retained about half of the total body fat.
4. While amino acid compositions of feathers and skin proteins were quite similar to data reported for other birds, carcass proteins were lower in methionine and lysine. 相似文献
2. A starter diet was given, ad libitum, from 7 to 21 and a finisher diet from 21 to 42 d of age. Body weight, weight gain, food intake and food conversion (FC) were determined at 3 and 6 weeks of age. Abdominal fat deposition (AFD), carcase yield, carcase fat and protein and nitrogen retention were determined at 6 weeks of age. During the starter period chicks were given a 231 g/kg crude protein (CP) diet and a low protein diet supplemented with synthetic amino acid, a: to National Research Council recommendations, b: to the concentration of the control diet, and c: in agreement with the pattern of body composition. Glutamic acid and glycine were added to some diets as sources of non‐essential amino acids (NEAA). All diets contained 12.62 MJ metabolisable energy (AMEn)/kg. The diets administered between 3 and 6 weeks were comparable to the starter diets, except that they contained more AMEn (12.85 MJ/kg) and less protein.
3. Performance equal to that of high protein controls was obtained with birds fed a low protein diet supplemented with synthetic essential and NEAA to the amounts in the control diet or based on the amino acid profile of body protein. This was not achieved with low protein diets supplemented with synthetic amino acids to the amounts recommended by NRC.
4. Without altering performances, the efficiency of protein utilisation of birds fed on low protein diets was superior to that of birds fed on the commercial control diet and their nitrogen excretion was reduced by 26%. The percentage carcase yield and protein was unaffected by the dietary regimen but carcase fat content and AFD increased as the protein content of the diet decreased.
5. These results show that it is possible to obtain the same performances with low protein diets supplemented with synthetic amino acids, using an ideal amino acid balance. However, low protein diets result in a higher carcase fat content. 相似文献
Carcass finish and tissue fat deposition were influenced more strongly by the level of ADF than by varying the E : P. The pronounced influence of ADF on the skin and tissue fat of immature turkeys indicates the potential value of increased ADF in diets for early marketed small turkeys.
The yield of carcass components other than skin was not strongly influenced by either ADF or E : P. The percentage eviscerated carcass and edible meat yield increased with age. The percentage yield of wing segments and drumstick decreased with age. Skin yield and tissue fat content first decreased, then increased with age.
Equations were derived to express the relationship of fat content with protein, moisture and age in thigh and breast meat. 相似文献
2. The weight of Alabio ducks at 12 weeks of age was increased by 40 and 48% by crossing with Muscovy and Pekin respectively. Pekin crosses grew faster to 8 or 12 weeks of age than Muscovy crosses but after 17 weeks of age there was no significant difference in weight. Food utilisation for Muscovy crosses was generally better at all ages.
3. Both at a given age and per unit of carcass weight, Muscovy crosses contained less fat and as a consequence more protein and ash, and a higher proportion of breast meat than Pekin crosses. Proportion of fat in Muscovy × Tegal ducks increased only slightly with carcass weight, while it decreased in Muscovy × Alabio ducks. 相似文献
2. Liver fat, carcass fat, liver weight and body weight increased markedly at the onset of sexual maturity.
3. Within the liver, the protein to DNA ratio did not alter significantly during development; glycogen was not consistently depleted by egg production.
4. Liver fat content was significantly correlated with carcass fat, liver weight and DNA concentration, and plasma total lipid and cholesterol, independent of stage of development; with body weight, liver protein, moisture, and protein to DNA ratio, excluding the period prior to commencement of sexual maturation; and with plasma phospholipid during lay.
5. Obesity was a feature of faster growing fowls which matured earlier, consumed more, utilised food less efficiently for egg production and produced fewer saleable eggs. 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. Lower body weights and lower feed consumption were observed in 4-week-old poults given 10 and 20 g/kg of AT-402 compared to poults given 0 or 5 g/kg.
3. Floor-reared poults, given either 5 or 10 g/kg AT-402 to 4 weeks of age, were significantly heavier than controls (0 g/kg AT-402), and feed conversion ratios for AT-402 given poults were improved.
4. Xylose uptake in 5 g/kg AT-402-fed poults was significantly greater than in poults given AT-402 at 0 and 10 g/kg, reflecting increased body weights of 5 g/kg AT-402-fed poults.
5. Delayed access by poults to the AT-402 until 10 d of age also improved 4-week body weights, suggesting that the AT-402 might improve performance as soon as it is given.
6. AT-402 at 5 g/kg was most efficacious as demonstrated by improved body weights and feed conversions. 相似文献
2. A 20% reduction in energy allowance from 23 to 34 weeks was associated with reduced body‐weight gain, egg weight and carcass constituents except ash, but had no significant effect on egg production or hatchability.
3. Increases in nutrient intake after 34 weeks were associated with an increase in body‐weight gain and carcass fat.
4. Moderate decreases in energy intake after 34 weeks were associated with reduced body‐weight gain, and a 15% reduction in nutrient intake resulted in a decrease in body weight and egg weight.
5. It is suggested that a feeding allowance which controls body‐weight gain during early lay, and then allows for a gradual increase in body weight over the breeding period may be the most efficient way of feeding the broiler breeder hen. 相似文献
2. Body‐weight gain and carcass fat and water content increased and fertility decreased with increasing energy allowance. Maximum egg production occurred at an energy intake of 1.73 MJ AME/bird d.
3. Differences in egg weight and hatchability were related to differences in both energy and protein intake. The highest egg weight occurred at the highest allowance of energy and protein. Hatchability was depressed where the daily allowances of protein and energy were in a ratio of more than 15 g protein: 1 MJ AME.
4. Apart from egg size no significant effects on reproductive performance were observed when dietary protein intake was varied from 27 to 19.5 g/bird d.
5. Requirements of broiler breeder hens for protein during lay may be lower than previously thought. For the strain used a protein intake of 19.5 g/bird d appeared adequate provided essential amino acid concentrations were maintained.
6. The close relationships between body weight and energy allowance and the latter and egg production make body‐weight gain a useful guide to management. A body‐weight gain of about 1.1 kg from 21 to 36 weeks of age was associated with optimum performance in this study. 相似文献
2. The regression of food consumption on the linear effects of age, protein, energy and protein × energy interaction, and the quadratic effect of age accounted for 94% of the observed variation. The regression of food utilisation on the linear effects of protein, energy, and age and the quadratic effects of dietary protein and age accounted for 97% of the observed variation. Food consumption and efficiency were dependent on both dietary protein and energy, increasing with increases in either dietary protein or energy content.
3. The regression of fat in the dressed carcass on the linear effects of protein, energy and age accounted for 19% of the observed variation. Carcass fat increased with increasing age and dietary energy, and decreased with increasing dietary protein.
4. Although body weight, food consumption and utilisation were significantly different between trials, the proportion of carcass fat was not. 相似文献
2. Poults fed on diets with no supplementary riboflavin had poor gait scores, decreased times to sit and higher rates of culling compared to poults fed on the control diet (20 mg biotin and 0.3 mg riboflavin/kg diet). Histologically, riboflavin deficiency was associated with a peripheral neuropathy similar to that described previously in chicks and, unexpectedly, in growth plate abnormalities.
3. Tibiae of poults fed on the control diet were larger, more dense, stronger and stiffer than the diets with no supplementary riboflavin.
4. Increasing supplementary biotin in poults fed on diets with no supplementary riboflavin was associated with a decrease in tibia weight, density, strength and stiffness.
5. The results demonstrated that riboflavin deficiency in fast-growing turkey poults was associated with growth retardation, growth plate disturbance and peripheral nerve dysfunction leading to an inability to walk. 相似文献
2. Plasma VLDL plus LDL triglyceride concentrations were similar in males and females and only slightly higher in birds fed on the high‐fat diet. Concentrations at 3 weeks were similar to those at 7 weeks.
3. Body fat content was correlated more closely with plasma VLDL plus LDL triglyceride measured at 7 weeks than at 3 weeks.
4. Phenotypic correlations between body fat content and plasma VLDL plus LDL triglyceride concentrations at 7 weeks were 0.47 and 0.43 for males and females respectively fed on the high‐fat diet and 0.70 and 0.60 for males and females fed on the low‐fat diet.
5. Phenotypic correlations between body fat content and measurements with an abdominal caliper were 0.35 and 0.49 in birds fed on the high‐ and low‐fat diets respectively.
6. A possible procedure for selecting for leanness in broiler breeding programmes on the basis of measurements of plasma VLDL plus LDL triglycerides is discussed. 相似文献
2. Water intake was consistently higher in the 0.25, 0.40 and commercial restriction treatments.
3. There was a negative curvilinear relationship at each age between body weight and the heterophil‐lymphocyte ratio and plasma corticosterone concentration.
4. There was a positive relationship between the plasma concentration of creatine kinase and body weight at 12 and 18 weeks of age. The relationships between body weight and the plasma activity of alkaline phosphatase and aspartate transaminase changed with age and there were no differences between treatments for lactate dehydrogenase.
5. The time spent resting increased with body weight at each age. The relationship between time spent preening and body weight changed with age whereas that for oral activities was similar among restricted birds at 6, and among all treatments at 12 weeks of age. At 18 weeks there was an increase in oral activities with decreasing body weight.
6. Fearfulness was positively related to body weight. The response of the comb to phytohaemagglutinin injection was similar in all treatments and the antibody titre to injections of sheep red blood cells was curvilinear.
7. A principal components analysis of all measured traits at 6, 12 and 18 weeks of age was conducted. Most of the variables were redundant but at least one from each of the different classes of welfare indices was retained at 6 and 12 weeks of age.
8. It was concluded that a body weight during rearing in the range of 0.5 to 0.85 of ad libitum might provide for optimum welfare of broiler breeder females. 相似文献
2. Plasma VLDL concentrations were consistently higher at all ages in fat line hens but were not affected by dietary treatment.
3. Mature body weight did not differ between the lines in birds fed ad libitum but with food restriction throughout life, fat line birds were lighter at 34 weeks.
4. There was little difference between the lines in abdominal fatness of birds fed ad libitum up to 60 weeks. Fat line birds were always fatter than lean line counterparts under food restriction.
5. Egg production was higher in lean line birds fed ad libitum but food restriction improved egg production in both lines. Peak egg productions were similar in both lines but there was evidence that the optimal food allowances for egg production was higher in the lean compared with the fat line.
6. Ovarian yellow follicle numbers were highest at 34 weeks in ad libitum fed lean line birds and declined linearly with decreasing body weight caused by food restriction but there was no such relationship in fat line birds.
7. White follicle numbers were higher and follicular atresia was lower in the lean line.
8. It is concluded that poor reproduction in fat line birds was associated with inhibition of follicular development and atresia rather than by high plasma VLDL concentrations promoting excessive yolk formation. 相似文献
2. When a milled, unsupplemented diet based on rice and groundnut was fed, food utilisation, carcass fat content and serum aspartate amino transferase [EG 2.6.1.1] activity indicated the need for supplementation with at least 3 mg pyridoxine, or a total concentration of 8.8 mg/kg diet.
3. With a maize‐groundnut diet body‐weight gain, food intake and tissue aspartate aminotransferase activities suggested that dietary supplementation with pyridoxine was unnecessary, but food utilisation indicated a need for supplementation with 3 mg or a total intake of 9 mg pyridoxine/ kg diet.
4. A practical broiler chick starter diet was used to show that the total concentration of pyridoxine should be at least 7.2 mg/kg when maize‐groundnut diets are fed. 相似文献
2. At 8 weeks of age, selected chickens were different in glucose tolerance but similar in body weight, food conversion efficiency, carcass composition and glucose‐induced insulin release.
3. Therefore, variations in glucose regulation and insulin sensitivity which are detectable at an early age, do not appear to be related to body composition in 8‐week‐old broilers. 相似文献
2. Guinea fowls had higher body weight, hot carcass weight, cold dressed weight and breast weight than chickens.
3. Guinea fowls had more dry matter, protein and less fat than chickens. Ash content did not differ between guinea fowls and chickens. Protein and fat increased, whereas dry matter and ash decreased with age (P < 0.05)
4. Chicken meat was lighter, less red and more yellow than guinea fowl meat. Cooking loss was higher in guinea fowls, male and grower birds than chickens, females and adult birds, respectively. Shear force was affected by age, as mature birds had a higher value than growers.
5. Guinea fowl carcasses contained more meat that was leaner, higher in protein and redder compared with chicken meat. As age increased the meat increased in protein and fat content and shear force, whereas colour became darker, redder and yellower. 相似文献